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Sample records for abandoned carbonate reservoir

  1. REVIVING ABANDONED RESERVOIRS WITH HIGH-PRESSURE AIR INJECTION: APPLICATION IN A FRACTURED AND KARSTED DOLOMITE RESERVOIR

    SciTech Connect

    Robert Loucks; Steve Ruppel; Julia Gale; Jon Holder; Jon Olsen; Deanna Combs; Dhiraj Dembla; Leonel Gomez

    2003-06-01

    The Bureau of Economic Geology and Goldrus Producing Company have assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The characterization phase of the project is utilizing geoscientists and petroleum engineers from the bureau of Economic Geology and the Department of Petroleum Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. This model will be used to define a field deployment plant that Goldrus, a small independent oil company, will implement by drilling both vertical and horizontal wells during the demonstration phase of the project. Additional reservoir data are being gathered during the demonstration phase to improve the accuracy of the reservoir model. The results of the demonstration are being closely monitored to provide a basis for improving the design of the HPAI field deployment plan. The results of the reservoir characterization field demonstration and monitoring program will be documented and widely disseminated to facilitate adoption of this technology by oil operators in the Permian Basin and elsewhere in the US.

  2. Reviving Abandoned Reservoirs with High-Pressure Air Injection: Application in a Fractured and Karsted Dolomite Reservoir

    SciTech Connect

    Robert Loucks; Stephen C. Ruppel; Dembla Dhiraj; Julia Gale; Jon Holder; Jeff Kane; Jon Olson; John A. Jackson; Katherine G. Jackson

    2006-09-30

    Despite declining production rates, existing reservoirs in the United States contain vast volumes of remaining oil that is not being effectively recovered. This oil resource constitutes a huge target for the development and application of modern, cost-effective technologies for producing oil. Chief among the barriers to the recovery of this oil are the high costs of designing and implementing conventional advanced recovery technologies in these mature, in many cases pressure-depleted, reservoirs. An additional, increasingly significant barrier is the lack of vital technical expertise necessary for the application of these technologies. This lack of expertise is especially notable among the small operators and independents that operate many of these mature, yet oil-rich, reservoirs. We addressed these barriers to more effective oil recovery by developing, testing, applying, and documenting an innovative technology that can be used by even the smallest operator to significantly increase the flow of oil from mature U.S. reservoirs. The Bureau of Economic Geology and Goldrus Producing Company assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The Permian Basin, the largest oil-bearing basin in North America, contains more than 70 billion barrels of remaining oil in place and is an ideal venue to validate this technology. We have demonstrated the potential of HPAI for oil-recovery improvement in preliminary laboratory tests and a reservoir pilot project. To more completely test the technology, this project emphasized detailed characterization of reservoir properties, which were integrated to access the effectiveness and economics of HPAI. The characterization phase of the project utilized geoscientists and petroleum engineers from the Bureau of Economic Geology and the Department of Petroleum

  3. Carbonate petroleum reservoirs

    SciTech Connect

    Roehl, P.O.; Choquette, P.W.

    1985-01-01

    This book presents papers on the geology of petroleum deposits. Topics considered include diagenesis, porosity, dolomite reservoirs, deposition, reservoir rock, reefs, morphology, fracture-controlled production, Cenozoic reservoirs, Mesozoic reservoirs, and Paleozoic reservoirs.

  4. Tertiary carbonate reservoirs in Indonesia

    SciTech Connect

    Nayoan, G.A.S.; Arpandi; Siregar, M.

    1981-01-01

    Hydrocarbon production from Tertiary carbonate reservoirs accounted for ca. 10% of daily Indonesian production at the beginning of 1978. Environmentally, the reservoirs appear as parts of reef complexes and high-energy carbonate deposits within basinal areas situated mainly in the back arc of the archipelago. Good porosities of the reservoirs are represented by vugular/moldic and intergranular porosity types. The reservoirs are capable of producing prolific amounts of hydrocarbons: production tests in Salawati-Irian Jaya reaches maximum values of 32,000 bpd, and in Arun-North Sumatra tests recorded 200 MMCF gas/day. Significant hydrocarbon accumulations are related to good reservoir rocks in carbonates deposited as patch reefs, pinnacle reefs, and platform complexes. Exploration efforts expand continuously within carbonate formations which are extensive horizontally as well as vertically in the Tertiary stratigraphic column.

  5. Functional wettability in carbonate reservoirs

    DOE PAGES

    Brady, Patrick V.; Thyne, Geoffrey

    2016-10-11

    Oil adsorbs to carbonate reservoirs indirectly through a relatively thick separating water layer, and directly to the surface through a relatively thin intervening water layer. Whereas directly sorbed oil desorbs slowly and incompletely in response to changes in reservoir conditions, indirectly sorbed oil can be rapidly desorbed by changing the chemistry of the separating water layer. The additional recovery might be as much as 30% original oil in place (OOIP) above the ~30% OOIP recovered from carbonates through reservoir depressurization (primary production) and viscous displacement (waterflooding). Electrostatic adhesive forces are the dominant control over carbonate reservoir wettability. A surface complexationmore » model that quantifies electrostatic adhesion accurately predicts oil recovery trends for carbonates. Furthermore, the approach should therefore be useful for estimating initial wettability and designing fluids that improve oil recovery.« less

  6. Functional wettability in carbonate reservoirs

    SciTech Connect

    Brady, Patrick V.; Thyne, Geoffrey

    2016-10-11

    Oil adsorbs to carbonate reservoirs indirectly through a relatively thick separating water layer, and directly to the surface through a relatively thin intervening water layer. Whereas directly sorbed oil desorbs slowly and incompletely in response to changes in reservoir conditions, indirectly sorbed oil can be rapidly desorbed by changing the chemistry of the separating water layer. The additional recovery might be as much as 30% original oil in place (OOIP) above the ~30% OOIP recovered from carbonates through reservoir depressurization (primary production) and viscous displacement (waterflooding). Electrostatic adhesive forces are the dominant control over carbonate reservoir wettability. A surface complexation model that quantifies electrostatic adhesion accurately predicts oil recovery trends for carbonates. Furthermore, the approach should therefore be useful for estimating initial wettability and designing fluids that improve oil recovery.

  7. Functional wettability in carbonate reservoirs

    SciTech Connect

    Brady, Patrick V.; Thyne, Geoffrey

    2016-10-11

    Oil adsorbs to carbonate reservoirs indirectly through a relatively thick separating water layer, and directly to the surface through a relatively thin intervening water layer. Whereas directly sorbed oil desorbs slowly and incompletely in response to changes in reservoir conditions, indirectly sorbed oil can be rapidly desorbed by changing the chemistry of the separating water layer. The additional recovery might be as much as 30% original oil in place (OOIP) above the ~30% OOIP recovered from carbonates through reservoir depressurization (primary production) and viscous displacement (waterflooding). Electrostatic adhesive forces are the dominant control over carbonate reservoir wettability. A surface complexation model that quantifies electrostatic adhesion accurately predicts oil recovery trends for carbonates. Furthermore, the approach should therefore be useful for estimating initial wettability and designing fluids that improve oil recovery.

  8. REVIVING ABANDONED RESERVOIRS WITH HIGH-PRESSURE AIR INJECTION: APPLICATION IN A FRACTURED AND KARSTED DOLOMITE RESERVOIR

    SciTech Connect

    Robert Loucks; Steve Ruppel; Julia Gale; Jon Holder; Jon Olson; Deanna Combs; Dhiraj Dembla

    2004-06-01

    The Bureau of Economic Geology (BEG) and Goldrus Producing Company have assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The characterization phase of the project is utilizing geoscientists and petroleum engineers from the Bureau of Economic Geology (BEG) and the Department of Petroleum and Geosystems Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. This model will be used to define a field deployment plan that Goldrus, a small independent oil company, will implement by drilling both vertical and horizontal wells during the demonstration phase of the project. Additional reservoir data were to be generated during the demonstration phase to improve the accuracy of the reservoir model. The demonstration phase has been delayed by Goldrus because of funding problems. Since the first of the year, Goldrus has been active in searching for partners to help finance the project. To this end it has commissioned several small consulting studies to technically support its effort to secure a partner. After financial support is obtained, the demonstration phase of the project will proceed. Since just after the beginning of the year, BEG has curtailed project activities and spending of DOE funds except for the continued support of one engineering student. This student has now completed his work and has written a thesis describing his research (titled ''Stimulating enhanced oil recovery (EOR) by high-pressure air injection (HPAI) in west Texas light oil reservoir''). We plan to recommence our work on the project as soon as the operator obtains necessary funding to carry out the demonstration phase of the project. In order to complete all activities specified in the proposal, it will be necessary to request

  9. REVIVING ABANDONED RESERVOIRS WITH HIGH-PRESSURE AIR INJECTION: APPLICATION IN A FRACTURED AND KARSTED DOLOMITE RESERVOIR

    SciTech Connect

    Robert Loucks; Steve Ruppel; Julia Gale; Jon Holder; Jon Olson

    2005-01-01

    The Bureau of Economic Geology (BEG) and Goldrus Producing Company have assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The characterization phase of the project is utilizing geoscientists and petroleum engineers from the Bureau of Economic Geology (BEG) and the Department of Petroleum and Geosystems Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. This model will be used to define a field deployment plan that Goldrus, a small independent oil company, will implement by drilling both vertical and horizontal wells during the demonstration phase of the project. Additional reservoir data were to be generated during the demonstration phase to improve the accuracy of the reservoir model. The demonstration phase has been delayed by Goldrus because of funding problems. Since the first of the year, Goldrus has been active in searching for partners to help finance the project. After financial support is obtained, the demonstration phase of the project will proceed. Since just after the beginning of the year, BEG has curtailed project activities and spending of DOE funds except for the continued support of one engineering student. This student has now completed his work and his thesis was reported on in the last semi-annual report. We plan to recommence our work on the project as soon as the operator obtains necessary funding to carry out the demonstration phase of the project. In order to complete all activities specified in the proposal, we requested and received an extension of the project to September 30, 2005. We are confident that Goldrus will obtain the necessary funding to continue and that we can complete the project by the end of the extension data. We strongly believe that the results of

  10. Carbon content of sediments of small reservoirs

    SciTech Connect

    Ritchie, J.C. )

    1989-04-01

    Carbon content was measured in sediments deposited in 58 small reservoirs across the US. Reservoirs varied from 0.2 to 4,000 km{sup 2} in surface area. The carbon content of sediment ranged from 0.3 to 5.6 percent, with a mean of 1.9 {plus minus} 1.1 percent. No significant differences between the soil and sediment carbon content were found using a paired t-test or ANOVA. The carbon content of sediments in reservoirs was similar to the carbon content of surface soils in the watershed, except in watersheds with shrub or steppe (desert) vegetation. Based on the sediment accumulation rates measured in each reservoir, the calculated organic carbon accumulation rates among reservoirs ranged from 26 to 3,700 gC m{sup {minus}2} yr{sup {minus}1}, with a mean of 675 {plus minus} 739 gC m{sup {minus}2} yr{sup {minus}1}. The carbon content and accumulation rates were highest in sediments from grassland watersheds. High variability was found in carbon content, carbon accumulation, and sediment accumulation rates due to individual watershed and reservoir characteristics rather than to any broad physiographic patterns. The carbon accumulation rates in these reservoir sediments indicate that reservoir sediments could be a significant sink of organic carbon.

  11. Hydrogeological definition and applicability of abandoned coal mines as water reservoirs.

    PubMed

    Ordóñez, A; Jardón, S; Álvarez, R; Andrés, C; Pendás, F

    2012-08-01

    Hydrogeologically, the Central Coal Basin (Asturias, Spain) is characterized by predominantly low-permeability materials that make up a multilayer aquifer with very low porosity and permeability values, where the sandstones act as limited aquifers, and wackes, mudstones, shales and coal seams act as confining levels. Preferential groundwater flow paths are open fractures and zones of decompression associated with them, so the hydraulic behaviour of the system is more associated with fracturing than lithology. Thus, abandoned and flooded mines in the area acquire an important role in the management of water resources, setting up an artificial "pseudo-karst" aquifer. This paper evaluates the potential application of the abandoned mines as underground reservoirs, both for water supply and energetic use, mainly through heat pumps and small hydropower plants. In particular, the groundwater reservoir shaped by the connected shafts Barredo and Figaredo has been chosen, and a detailed and multifaceted study has been undertaken in the area. The exposed applications fit with an integrated management of water resources and contribute to improve economic and social conditions of a traditional mining area in gradual decline due to the cessation of such activity.

  12. Carbon emission from global hydroelectric reservoirs revisited.

    PubMed

    Li, Siyue; Zhang, Quanfa

    2014-12-01

    Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO2)/year and 18.7 Tg methane (CH4)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO2 and 67 % CH4 of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 5.7 g CH4/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO2eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs.

  13. Bioaccumulation of cesium-137 in yellow bullhead catfish (Ameiurus natalis) inhabiting an abandoned nuclear reactor reservoir

    SciTech Connect

    McCreedy, C.D.; Glickman, L.T.; Jagoe, C.H.; Brisbin, I.L. Jr.

    1997-02-01

    Bioaccumulation of {sup 137}Cs was investigated in yellow bullhead catfish (Ameiurus natalis) inhabiting an abandoned reactor reservoir, Pond B, Savannah River Site, Barnwell Co., South Carolina. The authors collected fish by trap-netting, and determined ages from pectoral spines. Muscle and other tissues were assayed for {sup 137}Cs by NaI-scintillation. Music {sup 137}Cs was unrelated to sex or mass of fish, but was related to age. Examination of least-squares means suggested that {sup 137}Cs in muscle increased up to about age 3, but did not increase with greater age. A modified Richards model showed equilibrium {sup 137}Cs concentration in muscle was acquired in approximately 2.4 years. Growth differed between sexes and the time to asymptotic body mass was longer than the time to attain equilibrium {sup 137}Cs concentration. Males attained an asymptotic mass of 577 g in approximately 6.3 years; females attained an asymptotic mass of 438 g in approximately 5.9 years. The cumulative {sup 137}Cs burden of the population was 4.9 {times} 10{sup 6} Bq, representing <0.001% of the {sup 137}Cs inventory of the reservoir. Concentration of {sup 137}Cs varied among tissues with gill and muscle the lowest and highest. Concentration of {sup 137}Cs in ovaries declined with increasing ovary mass. Until equilibrium is attained in these fish, {sup 137}Cs concentration is directly related to increasing age rather than size.

  14. Quantification of geologic descriptions for reservoir characterization in carbonate reservoirs

    SciTech Connect

    Lucia, F.J.; Vander Stoep, G.W. )

    1990-05-01

    Recognition that a large volume of oil remains in carbonate reservoirs at the end of primary depletion and waterflooding has prompted the reevaluation of the reserve-growth potential of many existing carbonate reservoirs. Types of numerical data required include porosity, absolute permeability, relative permeability, fluid saturation, and capillary pressure, all of which are related to the size and distribution of pore space. Rock fabrics control the size and distribution of pore space and define facies that best characterize carbonate reservoirs. Thus, the link between facies descriptions and numerical engineering data is the relationship between pore-size distribution and present carbonate rock fabric. The most effective way to convert facies descriptions into engineering parameters is by considering three basic rock-fabric categories. The first category is interparticle pore space (both intergranular and intercrystalline pore types) with pore-size distribution controlled primarily by the size and shape of grains or crystals. Grain or crystal size is the key geologic measurement and, along with porosity, provides the basis for converting geologic descriptions into values for permeability, saturation, and capillarity. The second category is separate-vug pore space, such as moldic or intraparticle pore space. Separate-vug pore space adds porosity but little permeability to the reservoir rock. The contribution to saturation and capillarity depends upon the size of the separate-vug pore space. For example, moldic separate vugs will be saturated with oil, whereas microporous grains will be saturated with water. The third category is touching-vug pore space, which is vuggy pore space that is interconnected on a reservoir scale. The engineering parameters for this category are related to three diagenetic and tectonic factors.

  15. Post-Soviet cropland abandonment and carbon sequestration in European Russia, Ukraine, and Belarus

    NASA Astrophysics Data System (ADS)

    Schierhorn, Florian; Müller, Daniel; Beringer, Tim; Prishchepov, Alexander V.; Kuemmerle, Tobias; Balmann, Alfons

    2013-12-01

    Widespread cropland abandonment occurred after the collapse of socialism across the former Soviet Union, but the rates and spatial patterns of abandoned lands are not well known. As a result, the potential of this region to contribute to global food production and estimates of the carbon sink developing on currently idle lands are highly uncertain. We developed a spatial allocation model that distributes yearly and subnational sown area statistics to the most agriculturally suitable plots. This approach resulted in new, high-resolution (1 km2) annual time series of cropland and abandoned lands in European Russia, Ukraine, and Belarus from 1990 to 2009. A quantitative validation of the cropland map confirms the reliability of this data set, especially for the most important agricultural areas of the study region. Overall, we found a total of 87 Mha of cropland and 31 Mha of abandoned cropland in European Russia, Ukraine, and Belarus combined, suggesting that abandonment has been severely underestimated in the past. The abandonment rates were highest in European Russia. Feeding our new map data set into the dynamic vegetation model LPJmL revealed that cropland abandonment resulted in a net carbon sink of 470 TgC for 1990 to 2009. Carbon sequestration was generally slow in the early years after abandonment, but carbon uptake increased significantly after approximately 10 years. Recultivation of older abandoned lands would be associated with high carbon emissions and lead to substantial amounts of carbon not being sequestered in vegetation formations currently developing on idle croplands. Our spatially and temporally explicit cropland abandonment data improve the estimation of trade-offs involved in reclaiming abandoned croplands and thus in increasing agricultural production in this globally important agricultural region.

  16. C02 Huff-n-Puff Process in a Light Oil Shallow Shelf Carbonate Reservoir

    SciTech Connect

    Mark Kovar; Scott Wehner

    1998-01-31

    The principal objective of this CO2 Huf-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the CO2 H-n-P process, coupled with reservoir characterization components are to be used to determine if this process is technically and economically feasible for field implementation. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan of increasing oil production and deferring abandonment of shallow shelf carbonate reservoirs.

  17. Design and Implementation of a CO2 Flood Utilizing Advanced Reservoir Characterization and Horizontal Injection Wells In a Shallow Shelf Carbonate Approaching Waterflood Depletion, Class II

    SciTech Connect

    Wier, Don R. Chimanhusky, John S.; Czirr, Kirk L.; Hallenbeck, Larry; Gerard, Matthew G.; Dollens, Kim B.; Owen, Rex; Gaddis, Maurice; Moshell, M.K.

    2002-11-18

    The purpose of this project was to economically design an optimum carbon dioxide (CO2) flood for a mature waterflood nearing its economic abandonment. The original project utilized advanced reservoir characterization and CO2 horizontal injection wells as the primary methods to redevelop the South Cowden Unit (SCU). The development plans; project implementation and reservoir management techniques were to be transferred to the public domain to assist in preventing premature abandonment of similar fields.

  18. Models for naturally fractured, carbonate reservoir simulations

    SciTech Connect

    Tuncay, K.; Park, A.; Ozkan, G.; Zhan, X.; Ortoleva, P.; Hoak, T.; Sundberg, K.

    1998-12-31

    This report outlines the need for new tools for the simulation of fractured carbonate reservoirs. Several problems are identified that call for the development of new reservoir simulation physical models and numerical techniques. These include: karst and vuggy media wherein Darcy`s and traditional multi-phase flow laws do not apply; the need for predicting the preproduction state of fracturing and stress so that the later response of effective stress-dependent reservoirs can be predicted; and methods for predicting the fracturing and collapse of vuggy and karst reservoirs in response to draw-down pressure created during production. Specific research directions for addressing each problem are outlined and preliminary results are noted.

  19. Fate of Organic Carbon Deposited in Reservoirs

    NASA Astrophysics Data System (ADS)

    Huntington, T. G.; Rhoton, F. E.; Bennett, S. J.; Hudnall, W. H.

    2002-05-01

    Sedimentation of soil organic carbon (SOC) eroded from uplands and deposited in reservoirs could be an important mechanism for carbon sequestration provided that it is conserved during transport and burial and that uplands are not experiencing net loss. There are uncertainties in both these assumptions and gaining a better understanding of these processes is a key objective of ongoing carbon-cycle investigations. The U.S. Geological Survey, the U. S. Department of Agriculture, and Louisiana State University Agricultural Center are collaborating on an investigation of soils and sediments in the Yalobusha River Basin in Mississippi. Sediment cores were collected from upland soils and from Grenada Lake, a flood control reservoir, in the basin. Suspended sediments have been collected from the Yalobusha River and one of its tributaries upstream of the lake. We are measuring carbon mineralization potential in conjunction with carbon and nitrogen concentrations, 13C, mineralogy, and texture on sediments and upland soils to determine whether eroding SOC is conserved or oxidized during transport and burial. Differences in mineralization potential and other chemical and physical properties are used to infer net changes in the original eroding SOC. Autochthonous production of SOC within reservoirs could replace labile SOC oxidized during transport and burial thereby masking losses due to oxidation. Autochthonous sources can be evaluated by chemical and physical characterization of the sediments. Stable carbon isotope (13C) geochemistry provides a tool for distinguishing the two primary sources of organic carbon incorporated in lake sediments because allochthonous SOC from the surrounding watershed is, in general, less depleted in stable 13C than autochthonous SOC produced in the lake by aquatic organisms such as macrophytes and phytoplankton. The integration of the 13C signature recorded in the organic fraction of the lake sediments with total organic carbon, C/N ratio

  20. Land abandonment, fire recurrence and soil carbon content in the Macizo del Caroig, Eastern Spain

    NASA Astrophysics Data System (ADS)

    Cerdá, A.; González Peñaloza, F.; Santín, C.; Doerr, S. H.

    2012-04-01

    During the last 50 years two main forces have driven the fate of Mediterranean landscapes: land abandonment and forest fires (MacDonald et al., 2000; Moreira et al., 2001). Due to the economical changes suffered by the of the Mediterranean countries after the Second World War, the population migrated from the rural to the urban areas, and from South to North Europe. The land abandonment allowed the vegetation to recover and, as a consequence, an increase in forest fire took place. The soils of the abandoned land recovered the vegetation and litter layers, and consequently changes in soil properties have being found. One of these changes is the increase of soil carbon content, which is due both to vegetation recovery and to fire occurrence that increases the ash and pyrogenic carbon content in soils. Twenty plots were selected in the Macizo del Caroig in Eastern Spain on soils developed on limestone. The period of abandonment and the forest fires that had affected each plot were determined by interviews with the owners, farmers and shepherds. In addition, six (three + three) plots were selected as forest (no plough) and cultivated control plots. Each plot was sampled (10 random samples) and the organic carbon content determined. The results show that the cultivated plots have organic matter contents of 1.02 %, and the forest (Quercus ilex sp.) plots reach the highest value: 14.98 %. Within those we found values that range from 2.34 %, in the recently abandoned plots (10 year abandonment), to values of 8.23 % in the 50 year old abandoned fields.The results demonstrate that there is a recovery of the organic carbon in abandoned soils and that the forest fires do no affect this trend. The increase of soil organic matter after abandonment is a result of the recovery of vegetation(Debussche et al., 2001), which is the consequence of the end of the disturbance of forest that have affected the Mediterranean for millennia (Barbero et al., 1990). The colonization of the

  1. Microbial enhancement of oil production from carbonate reservoirs

    SciTech Connect

    Tanner, R.S.; Knapp, R.M.; McInerney, M.J.; Udegbunam, E.O.

    1991-01-01

    The goal of this work is to evaluate the potential for Microbial Enhanced Oil Recovery (MEOR) in carbonate reservoirs. Specific objectives include: review of the literature pertinent to MEOR in carbonate reservoirs, a study of the microbial ecology of carbonate reservoirs, isolation of microorganisms and their end-products of metabolism on carbonate pore structure, the recovery of residual oil from carbonates in model core systems, and development of models to examine and predict MEOR processes in carbonate reservoirs. 1 ref., 3 figs., 1 tab.

  2. Post-Soviet farmland abandonment, forest recovery, and carbon storage potential in Ukraine

    NASA Astrophysics Data System (ADS)

    Olofsson, P.; Kuemmerle, T.; Baumann, M.; Radeloff, V. C.; Woodcock, C. E.; Hostert, P.

    2010-12-01

    Land use is a critical factor in the global carbon cycle, but land use effects on carbon fluxes are poorly understood in many regions. One such region is the former Eastern Bloc, where land use intensity decreased substantially after the collapse of the Soviet Union, resulting in widespread farmland abandonment and forest regrowth. The aim of this study was to examine how land use trends altered net carbon fluxes in Western Ukraine (57,000 km2) for the communist (1945-1991) and the post-communist period (1991-2007), and to assess the regions’ future carbon sequestration potential. Forest disturbance and farmland abandonment between 1988 to 2007 was estimated from Landsat imagery in former study. Historical land use change rates were obtained from forest inventories to reconstruct forest trends back to the mid-1800s. Using a carbon book-keeping model, we quantified net carbon fluxes from land use change and assessed potential future carbon fluxes for a range of reforestation and logging scenarios. Our results suggest that the low-point in forest cover occurred in the 1920s. Forest expansion in the second half of the 20th century turned the region from a carbon source to a sink, despite heavy logging during Soviet times. The current land-use related sink strength is about 1.5 Tg of carbon per year. Sequestration potential on abandoned farmland is enormous, even when assuming that only a minor fraction of the currently abandoned land will revert to forests. Beyond our study area, farmland abandonment has been widespread throughout Eastern Europe and the former Soviet Union, suggesting that a substantial proportion of the regions’ industrial carbon emissions may be offset by reforesting farmland.

  3. Advances in carbonate exploration and reservoir analysis

    USGS Publications Warehouse

    Garland, J.; Neilson, J.; Laubach, S.E.; Whidden, Katherine J.

    2012-01-01

    The development of innovative techniques and concepts, and the emergence of new plays in carbonate rocks are creating a resurgence of oil and gas discoveries worldwide. The maturity of a basin and the application of exploration concepts have a fundamental influence on exploration strategies. Exploration success often occurs in underexplored basins by applying existing established geological concepts. This approach is commonly undertaken when new basins ‘open up’ owing to previous political upheavals. The strategy of using new techniques in a proven mature area is particularly appropriate when dealing with unconventional resources (heavy oil, bitumen, stranded gas), while the application of new play concepts (such as lacustrine carbonates) to new areas (i.e. ultra-deep South Atlantic basins) epitomizes frontier exploration. Many low-matrix-porosity hydrocarbon reservoirs are productive because permeability is controlled by fractures and faults. Understanding basic fracture properties is critical in reducing geological risk and therefore reducing well costs and increasing well recovery. The advent of resource plays in carbonate rocks, and the long-standing recognition of naturally fractured carbonate reservoirs means that new fracture and fault analysis and prediction techniques and concepts are essential.

  4. Agricultural land abandonment in Mediterranean environment provides ecosystem services via soil carbon sequestration.

    PubMed

    Novara, Agata; Gristina, Luciano; Sala, Giovanna; Galati, Antonino; Crescimanno, Maria; Cerdà, Artemi; Badalamenti, Emilio; La Mantia, Tommaso

    2017-01-15

    Abandonment of agricultural land leads to several consequences for ecosystem functions. Agricultural abandonment may be a significant and low cost strategy for carbon sequestration and mitigation of anthropogenic CO2 emissions due to the vegetation recovery and increase in soil organic matter. The aim of this study was to: (i) estimate the influence of different Soil Regions (areas characterized by a typical climate and parent material association) and Bioclimates (zones with homogeneous climatic regions and thermotype indices) on soil organic carbon (SOC) dynamics after agricultural land abandonment; and (ii) to analyse the efficiency of the agri-environment policy (agri-environment measures) suggested by the European Commission in relation to potential SOC stock ability in the Sicilian Region (Italy). In order to quantify the effects of agricultural abandonment on SOC, a dataset with original data that was sampled in Sicily and existing data from the literature were analysed according to the IPCC (Intergovernmental Panel on Climate Change) methodology. Results showed that abandonment of cropland soils increased SOC stock by 9.03MgCha(-1) on average, ranging from 5.4MgCha(-1) to 26.7MgCha(-1) in relation to the Soil Region and Bioclimate. The estimation of SOC change after agricultural use permitted calculation of the payments for ecosystem service (PES) of C sequestration after agricultural land abandonment in relation to environmental benefits, increasing in this way the efficiency of PES. Considering the 14,337ha of abandoned lands in Sicily, the CO2 emission as a whole was reduced by 887,745Mg CO2. Therefore, it could be concluded that abandoned agricultural fields represents a valid opportunity to mitigate agriculture sector emissions in Sicily. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Chemical and mineral control of soil carbon turnover in abandoned tropical pastures.

    Treesearch

    Erika Marín-Spiotta; Christopher W. Swanston; Margaret S. Torn; Whendee L. Silver; Sarah D. Burton

    2007-01-01

    We investigated changes in soil carbon (C) cycling with reforestation across a long-term, replicated chronosequence of tropical secondary forests regrowing on abandoned pastures. We applied CP MAS 13C NMR spectroscopy and radiocarbon modeling to soil density fractions from the top 10 cm to track changes in C chemistry and turnover during secondary forest establishment...

  6. Chemical and mineral control of soil carbon turnover in abandoned tropical pastures

    Treesearch

    Erika Marin-Spiotta; Christopher W. Swanston; Margaret S. Torn; Whendee L. Silver; Sarah D. Burton

    2008-01-01

    We investigated changes in soil carbon (C) cycling with reforestation across a long-term, replicated chronosequence of tropical secondary forests regrowing on abandoned pastures. We applied CP MAS 13C NMR spectroscopy and radiocarbon modeling to soil density fractions from the top 10 cm to track changes in C chemistry and turnover during...

  7. Diagenetic capping of carbonate reservoir facies

    SciTech Connect

    Lighty, R.G.

    1984-04-01

    The diagenetic model proposed involves the effect of submarine cementation on previously lithified carbonates, such as submerged relict shelf-margin buildups (e.g., drowned reefs, ooid shoals) or previously subaerially exposed formations (e.g., dune ridges) that were submerged by later sea level rise. These deposits generally have pronounced topographic relief (visible on seismic), good reservoir geometries, and high internal porosity of either primary or secondary origin. Petrologic studies on examples of both of these situations, a submerged early Holocene barrier reef off Florida and a 175-km (110-m) long submerged Pleistocene eolian ridge in the Bahamas, show that their exposed surface and uppermost facies (0.1 m, or 0.3 ft, below top) are further infilled and cemented, creating an extensively lithified, low porosity/low permeability zone or diagenetic cap rock. Quantitative mineralogic studies of occluding cements reveal an exponential reduction in porosity while moving upward into the seal zone. Submarine cements effectively infill and form a surficial permeability barrier that acts to impede further diagenesis and porosity reduction within underlying potential reservoir facies. To form this diagenetic seal only requires that the original carbonate buildup be resubmerged for some brief period of time prior to subsequent burial by sediments. If buildup accumulation later resumes without intermediate sediment burial, a common stratigraphic situation, the diagenetic seal would represent a disconformity separating two similar facies. The early formation of a diagenetic cap rock lends support to models of early hydrocarbon migration and emplacement. Prediction and recognition of submarine diagenetic seals will aid in exploration and development of obvious buildup reservoirs as well as subtle intraformational traps.

  8. Litter contribution to soil organic carbon in the agriculture abandons processes

    NASA Astrophysics Data System (ADS)

    Novara, A.; Rühl, J.; La Mantia, T.; Gristina, L.; La Bella, S.; Tuttolomondo, T.

    2015-02-01

    Mechanisms of litter decomposition, translocation and stabilization into soil layers are fundamental processes in ecosystem functioning as it regulates the cycle of soil organic matter (SOM), CO2 emission into the atmosphere, carbon sequestration into the soil. In this study, it was investigated the contribution of litters of different stages of Mediterranean secondary succession on Carbon sequestration, analyzing the role of earthworms on translocation of SOM into soil profile. For this purpose δ13C difference between meadow C4-Csoil and C3-Clitter were used in a field experiment. Four undisturbed litters of different stages of succession were collected (45, 70, 100 and 120 since agriculture abandon) and placed on the top of isolated soil cores. The litter contribution to C stock was affected by plant species and increased with the age of the stage of secondary succession. The soil organic carbon after 1 year since litter position increased up to 40% in comparison to no litter treatment in soil with litter of 120 years since abandon. The new carbon derived from C3-litter was decomposed and transferred into soil profile thanks to earthworms and dissolved organic carbon leaching. After 1 years the carbon increase attributed to earthworm activity ranged from 6 to 13% in soil under litter in field abandoned since 120 and 45 years, respectively.

  9. Litter contribution to soil organic carbon in the agriculture abandons processes

    NASA Astrophysics Data System (ADS)

    Novara, Agata; Francaviglia, Dario; La Mantia, tommaso; Gristina, Luciano; La Bella, Salvatore; Tuttolomondo, Teresa

    2015-04-01

    Mechanisms of litter decomposition, translocation and stabilization into soil layers are fundamental processes in ecosystem functioning as it regulates the cycle of soil organic matter (SOM), CO2 emission into the atmosphere, carbon sequestration into the soil. In this study, it was investigated the contribution of litters of different stages of Mediterranean secondary succession on Carbon sequestration, analyzing the role of earthworms on translocation of SOM into soil profile. For this purpose δ13C difference between meadow C4-C soil and C3-C litter were used in a field experiment. Four undisturbed litters of different stages of succession were collected (45, 70, 100 and 120 since agriculture abandon) and placed on the top of isolated soil cores. The litter contribution to C stock was affected by plant species and increased with the age of the stage of secondary succession. The soil organic carbon after 1 year since litter position increased up to 40% in comparison to no litter treatment in soil with litter of 120 years since abandon. The new carbon derived from C3-litter was decomposed and transferred into soil profile thanks to earthworms and dissolved organic carbon leaching. After 1 years the carbon increase attributed to earthworm activity ranged from 6% to 13% in soil under litter in field abandoned since 120 and 45 years, respectively.

  10. C02 Huff-n-Puff Process in a Light Oil shallow Shelf Carbonate Reservoir

    SciTech Connect

    Kovar, Mark; Wehner, Scott

    1997-06-30

    The principal objective of this CO2 Huff-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the CO2 H-n-P process, coupled with the Central Vacuum Unit (CVU) reservoir characterization components will be used to determine if this process is technically and economically feasible for field implementation. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of Energy's (DOE) objective of increasing domestic oil production and deferring the abandonment of shallow shelf carbonate (SSC) reservoirs. Tasks associated with this objective are carried out in what is considered a timely effort for near-term goals.

  11. Soil, vegetation and total organic carbon stock development in self-restoring abandoned vineyards

    NASA Astrophysics Data System (ADS)

    József Novák, Tibor; Incze, József; Spohn, Marie; Giani, Luise

    2016-04-01

    Abandoned vineyard's soil and vegetation development was studied on Tokaj Nagy-Hill, which is one of the traditional wine-producing regions of Hungary, it is declared as UNESCO World Heritage site as cultural landscape. Spatial distribution and pattern of vineyards were changing during the last several hundreds of years, therefore significant part of abandoned vineyards were subjected to long-term spontaneous secondary succession of vegetation and self-restoration of soils in absence of later cultivation. Two chronosequences of spontaneously regenerating vineyard abandonments, one on south (S-sequence) and one on southwest (SW-sequence) slope with differing times since their abandonment (193, 142, 101, 63, 39 and 14 years), were compiled and studied. The S-sequence was 25-35% sloped and strongly eroded, and the SW-sequence was 17-25% sloped and moderately eroded. The sites were investigated in respect of vegetation characteristics, soil physico-chemical characteristics, total organic carbon stocks (TOC stocks), accumulation rates of total organic carbon (TOC accumulation rates), and soil profiles, which were classified according to the World Reference Base (WRB) 2014. Vegetation development resulted in shrub-grassland mosaics, supplemented frequently by protected forb species and forest development at the earliest abandonment in S-sequence, and predominantly to forest vegetation in SW-sequence, where trees were only absent at the 63 and 14 years old abandonment sites. In all sites soils on level of reference groups according to WRB were classified, and Cambisols, Regosols, Calcisols, Leptosols, Chernozems and Phaeozems were found. Soils of the S-sequence show shallow remnants of loess cover with colluvic and redeposited soil materials containing 15-65% skeletal volcanic rock of weathering products coated by secondary calcium carbonates. The SW-sequence profiles are developed on deep loess or loess derivatives. The calcium-carbonate content was higher in profiles of

  12. REVIVING ABANDONED RESERVOIRS WITH HIGH-PRESSURE AIR INJECTION: APPLICATION IN A FRACTURED AND KARSTED DOLOMITE RESERVOIR

    SciTech Connect

    Robert Loucks; Stephen C. Ruppel

    2006-02-01

    The field operator, Goldrus Producing Company, has been unable to secure funding needed to continue the field demonstration phase of the project. Accordingly, we have temporarily halted all project activities until necessary funding is obtained. Goldrus felt confident that funds could be acquired by third quarter 2005 at which time it would have been necessary to request a project extension to complete the originally designed study. A project extension was granted but it appears Goldrus will have difficulty securing funds. We Bureau of Economic Geology are investigating a new approach on how to fulfill our initial objectives of promoting high-pressure air injection of Ellenburger reservoirs.

  13. Litter contribution to soil organic carbon in the processes of agriculture abandon

    NASA Astrophysics Data System (ADS)

    Novara, A.; Rühl, J.; La Mantia, T.; Gristina, L.; La Bella, S.; Tuttolomondo, T.

    2015-04-01

    The mechanisms of litter decomposition, translocation and stabilization into soil layers are fundamental processes in the functioning of the ecosystem, as they regulate the cycle of soil organic matter (SOM) and CO2 emission into the atmosphere. In this study the contribution of litters of different stages of Mediterranean secondary succession on carbon sequestration was investigated, analyzing the role of earthworms in the translocation of SOM into the soil profile. For this purpose the δ13C difference between meadow C4-C soil and C3-C litter was used in a field experiment. Four undisturbed litters of different stages of succession (45, 70, 100 and 120 since agriculture abandon) were collected and placed on the top of isolated C4 soil cores. The litter contribution to C stock was affected by plant species and it increased with the age of the stage of secondary succession. One year after the litter position, the soil organic carbon increased up to 40% in comparison to soils not treated with litter after 120 years of abandon. The new carbon derived from C3 litter was decomposed and transferred into soil profile thanks to earthworms and the leaching of dissolved organic carbon. After 1 year the carbon increase attributed to earthworm activity was 6 and 13% in the soils under litter of fields abandoned for 120 and 45 years, respectively.

  14. Pennsylvanian carbonate buildups, Paradox basin: Increasing reserves in heterogeneous, shallow-shelf reservoirs

    USGS Publications Warehouse

    Montgomery, S.L.; Chidsey, T.C.; Eby, D.E.; Lorenz, D.M.; Culham, W.E.

    1999-01-01

    Productive carbonate buildups of Pennsylvanian age in the southern Paradox basin, Utah, contain up to 200 million bbl remaining oil potentially recoverable by enhanced recovery methods. These buildups comprise over 100 satellite fields to the giant Greater Aneth field, where secondary recovery operations thus far have been concentrated. Several types of satellite buildups exist and produce oil from the Desert Creek zone of the Paradox Formation. Many of the relevant fields have undergone early abandonment; wells in Desert Creek carbonate mounds commonly produce at very high initial rates (>1000 bbl/day) and then suffer precipitous declines. An important new study focused on the detailed characterization of five separate reservoirs has resulted in significant information relevant to their future redevelopment. Completed assessment of Anasazi field suggests that phylloid algal mounds, the major productive buildup type in this area, consist of ten separate lithotypes and can be described in terms of a two-level reservoir system with an underlying high-permeability mound-core interval overlain by a lower permeability but volumetrically larger supramound (mound capping) interval. Reservoir simulations and related performance predictions indicate that CO2 flooding of these reservoirs should have considerable success in recovering remaining oil reserves.Productive carbonate buildups of Pennsylvanian age in the southern Paradox basin, Utah, contain up to 200 million bbl remaining oil potentially recoverable by enhanced recovery methods. These buildups comprise over 100 satellite fields to the giant Greater Aneth field, where secondary recovery operations thus far have been concentrated. Several types of satellite buildups exist and produce oil from the Desert Creek zone of the Paradox Formation. Many of the relevant fields have undergone early abandonment; wells in Desert Creek carbonate mounds commonly produce at very high initial rates (>1000 bbl/day) and then suffer

  15. How do soil properties and soil carbon stocks change after land abandonment in Mediterranean mountain areas?

    NASA Astrophysics Data System (ADS)

    Nadal Romero, Estela; Cammeraat, Erik; Pérez Cardiel, Estela; Lasanta, Teodoro

    2016-04-01

    Land abandonment and subsequent revegetation processes (due to secondary succession and afforestation practices) are global issues with important implications in Mediterranean mountain areas. Moreover, the effects of land use changes on soil carbon stocks are a matter of concern stated in international policy agendas on the mitigation of greenhouse emissions, and afforestation practices are increasingly viewed as an environmental restorative land use change prescription and are considered one of the most efficient carbon sequestration strategies currently available. The MED-AFFOREST project aims to gain more insight into the discussion by exploring the following central research questions: (i) what is the impact of land abandonment on soil properties? and (ii) how do soil organic carbon change after land abandonment? The main objective of this study is to assess the effects of land abandonment, land use change and afforestation practices on soil properties and soil organic carbon (SOC) dynamics. For this aim, five different land covers (bare soil, meadows, secondary succession, Pinus sylvestris (PS) and Pinus nigra (PN) afforestation), in the Central Spanish Pyrenees were analysed. Results showed that changes in soil properties after land abandonment were limited, even if afforestation practices were carried out and no differences were observed between natural succession and afforestation. The results on SOC dynamics showed that: (i) SOC contents were higher in the PN sites in the topsoil (10 cm), (ii) when all the profile was considered no significant differences were observed between meadows and PN, (iii) SOC accumulation under secondary succession is a slow process, and (iv) meadows should also be considered due to the relative importance in SOC stocks. The first step of SOC stabilization after afforestation is the formation of macro-aggregates promoted by large inputs of SOC, with a high contribution of labile organic matter. However, our respiration

  16. Reservoirs as hotspots of fluvial carbon cycling in peatland catchments.

    PubMed

    Stimson, A G; Allott, T E H; Boult, S; Evans, M G

    2017-02-15

    Inland water bodies are recognised as dynamic sites of carbon processing, and lakes and reservoirs draining peatland soils are particularly important, due to the potential for high carbon inputs combined with long water residence times. A carbon budget is presented here for a water supply reservoir (catchment area~9km(2)) draining an area of heavily eroded upland peat in the South Pennines, UK. It encompasses a two year dataset and quantifies reservoir dissolved organic carbon (DOC), particulate organic carbon (POC) and aqueous carbon dioxide (CO2(aq)) inputs and outputs. The budget shows the reservoir to be a hotspot of fluvial carbon cycling, as with high levels of POC influx it acts as a net sink of fluvial carbon and has the potential for significant gaseous carbon export. The reservoir alternates between acting as a producer and consumer of DOC (a pattern linked to rainfall and temperature) which provides evidence for transformations between different carbon species. In particular, the budget data accompanied by (14)C (radiocarbon) analyses provide evidence that POC-DOC transformations are a key process, occurring at rates which could represent at least ~10% of the fluvial carbon sink. To enable informed catchment management further research is needed to produce carbon cycle models more applicable to these environments, and on the implications of high POC levels for DOC composition. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Stratigraphy of Carbon Preservation in Reservoir Sediments, Elwha River, Washington

    NASA Astrophysics Data System (ADS)

    Stratton, L. E.; Wing, S.; Ritchie, A.; Grant, G.

    2015-12-01

    Dam removal revealed the facies architecture and distribution of detrital carbon in the sediments of two former large reservoirs, providing an unparalleled opportunity to develop a stratigraphic framework for understanding processing and storage of organic carbon in reservoir sediments. Incision following the 2011-2014 removal of Elwha (34 m high; Lake Aldwell reservoir) and Glines Canyon (64 m; Lake Mills reservoir) Dams on the Elwha River in Washington State exposed 85+ years accumulation of reservoir sediment in cross section, creating the first known opportunity to characterize post-impoundment sediments of a large reservoir in situ. In Lake Mills, the upstream reservoir, the Elwha River deposited an estimated 1.56x106 m3 sediment primarily in a steep-fronted, Gilbert-style delta, while deposition in downstream Lake Aldwell comprised only ~3.0x106 m3 sediment, deposited broadly in an elongate, low-angle delta. Allochthonous carbon is primarily preserved in delta foresets and complexly-bedded prodelta sands, with secondary lenses of coarse-grained organics deposited as channel-lag in migrating topset channels. Organic units tend to be coarse-grained, open-framework lenses and beds consisting of well-preserved branches, cones, and needles in the topset and foreset beds, while prodelta sands consist of well-sorted, well-preserved needles and leaves associated with fine sands and silts. Compared to Lake Mills, Lake Aldwell's delta deposits are lower angle and have finer, more organic-rich topset beds. Lacustrine beds in the main body of the reservoir are dominated by mineral sediments. Taking the average total organic carbon (TOC) content and geometry of individual facies provides a first-order estimate of the total organic carbon load in the reservoir sediments, and provides insight into the spatial variability of carbon deposition, a key challenge in understanding the carbon footprint of large water reservoirs.

  18. Quantification of functional soil organic carbon pools in a chronosequence of land abandonment in southern Spain.

    NASA Astrophysics Data System (ADS)

    Trigalet, Sylvain; Gabarrón-Galeote, Miguel A.; Van Oost, Kristof; van Wesemael, Bas

    2015-04-01

    Land abandonment is the dominant land use change in the Mediterranean, and determines the soil organic carbon (SOC) as the vegetation recovers during secondary succession. The rate of SOC recovery is influenced by environmental factors such as precipitation, soil properties or other local factors. Using aerial photographs taken in 1956, 1977, 1984, 1998, 2001 and 2009, a chronosequence of crop land abandonment was designed and topsoil samples were taken at each stage of recovery in a region North of Málaga. As SOC is a mixture of functional pools, it is important to isolate organic carbon with distinct functional properties to better understand the overall dynamic over decades. Using fractionation scheme introduced by Zimmermann et al. (2007), five fractions were isolated based on particle size, density and resistance: particulate organic matter (POM), dissolved organic carbon (DOC), SOC linked to silt and clay (s & c), SOC attached to sand particles or occluded in aggregates (S+A) and a chemically resistant fraction obtained by NaOCl oxidation (rSOC). Although there were no significant changes in particle-size distribution between the recovery stages (except for the croplands), there was a significant increase of S+A fraction over time (16 to 38%) at the expense of the s & c fraction (84 to 58%), indicating aggregation processes. Carbon concentrations within fractions S+A or rSOC did not change over time. Rather, carbon associated with silt and clay particles (s &c) was significantly affected after a few decades of abandonment. It increased from 5.7 gC.kg-1 in croplands to 10.3 gC.kg-1 in semi-natural plots. The chronosequence showed that carbon can be stored in more stable fractions. Taking into account active carbon (DOC + POM) and intermediate carbon (s & c, S+A) as indicators for carbon dynamics, we showed that the proportion of active carbon increased from 11% to 34% within the chronosequence. On the other hand, the proportion of slow cycling carbon

  19. Soil organic carbon accumulation in afforested/abandoned arable fields in Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Yi-Han; Cheng, Chih-Hsin; Huang, Yu-Hsuan

    2016-04-01

    Afforestation or abandonment of arable fields has been proposed as a way to increase terrestrial carbon storage and mitigate anthropogenic carbon emissions. When the arable fields are afforested or abandoned, the accumulation in soil organic carbon (SOC) is a key pool to sequestrate carbon. However, high uncertainties still exist in the tropics and subtropics because of fast SOC turnover rates and variable land use managements in these areas. In this study, a total of eleven sites with afforested/abandoned age over 15 years and elevation ranging from 16 to 2,056 m were investigated. We examined the increments of SOC by comparing with the adjacent tilled (e.g. croplands) and non-tilled (e.g. tea plantation or orchards) fields in two sampling layers, 0 - 10 and 10 - 20 cm in depth. In addition, density fractionation of SOC was also conducted in order to differentiate SOC into light fraction, intra-aggregate fraction, and heavy fraction to gain more information about the mechanism of SOC sequestration. Our results indicated that the increments of SOC concentration and stock varied with elevation, land use management, and soil depth. For the sites with elevation below 500 m, the SOC concentration and stock in the abandoned fields were 14.3 ± 0.9 mg C g-1 and 14.6 ± 4.6 Mg C ha-1 higher than the adjacent tilled fields, and 10.2 ± 6.3 mg C g-1and 6.4 ± 6.2 Mg C ha-1 higher than the adjacent non-tilled fields for surface 0-10 cm. For the sites with elevation above 500 m, the SOC concentration in the abandoned arable fields were 22.8 ± 12.8 mg C g-1 higher than the adjacent tilled fields, but the SOC stock might not be different due to high stone content in abandoned field. Moreover, the SOC concentration and stock in abandoned field were not different or even less than non-tilled fields where organic amendments were frequently applied. The increments of SOC for 10-20 cm soils were less evident than those for surface 0-10 cm soils, and the differences were only

  20. [Effects of land use and abandonment on soil labile organic carbon in the Karst region of southwest China].

    PubMed

    Liao, Hong-Kai; Li, Juan; Long, Jian; Zhang, Wen-Juan; Liu, Ling-Fei

    2014-01-01

    Effects of land use and land abandonment on labile organic carbon (LOC) in whole soils and different aggregate sizes were studied by sampling analysis of the soils in some typical land uses of the Karst region, southwest China. Results showed that the content and degree of dispersion of labile organic carbon decreased with soil depth, and the content of LOC was highly significant (P < 0.01) in 0-10 cm than in 10-20 cm and 20-30 cm. In the 0-10 cm soil layer, the content of LOC distribution in different aggregates was higher in the < 0.25 mm size, while no obvious changes of LOC among aggregates were found in the 10-20 cm and 20-30 cm depths. In different land use patterns, the LOC was the highest in paddy whether in whole soils or aggregates, followed by shrub, and the lowest in abandoned 3 years grassland. Within-between principal component analysis showed that the accumulation characters between land use and LOC were in the order of paddy > shrub > abandoned 15 years grassland = dry land > abandoned 3 years grassland, the content of LOC increased by 20.3% as compared to dryland, and had reached 80% of the content of shrub in abandoned 15 years grassland at the 0-10 cm depth, indicating that at the early stage of land abandonment, the natural recovery of carbon is relatively slow, while with the abandonment time increase, the carbon sink effect gradually appear.

  1. Pennsylvanian carbonate buildups, Paradox basin: Increasing reserves in heterogeneous, shallow-shelf reservoirs

    SciTech Connect

    Montgomery, S.L.; Chidsey, T.C. Jr.; Eby, D.E.; Lorenz, D.M.; Culham, W.E.

    1999-02-01

    Productive carbonate buildups of Pennsylvanian age in the southern Paradox basin, Utah, contain up to 200 million bbl remaining oil potentially recoverable by enhanced recovery methods. These buildups comprise over 100 satellite fields to the giant Greater Aneth field, where secondary recovery operations thus far have been concentrated. Several types of satellite buildups exist and produce oil from the Desert Creek zone of the Paradox Formation. Many of the relevant fields have undergone early abandonment; wells in Desert Creek carbonate mounds commonly produce at very high initial rates (>1000 bbl/day) and then suffer precipitous declines. An important new study focused on the detailed characterization of five separate reservoirs has resulted in significant information relevant to their future redevelopment. Completed assessment of Anasazi field suggests that phylloid algal mounts, the major productive buildup type in this area, consist of ten separate lithotypes and can be described in terms of a two-level reservoir system with an underlying high-permeability mound-core interval overlain by a lower permeability but volumetrically larger supramound (mound capping) interval. Reservoir simulations and related performance predictions indicate that CO{sub 2} flooding of these reservoirs should have considerable success in recovering remaining oil reserves.

  2. Changes in organic carbon pools and C sequestration potential in abandoned Chernozems

    NASA Astrophysics Data System (ADS)

    Lopes de Gerenyu, V.; Kurganova, I.; Kuzyakov, Y.

    2009-04-01

    Land use system in Russia has been significantly changed since 1990. More than quarter of croplands (about 34 M ha) including soils of southern regions (Chernozems. Kastanozems) was abandoned. The abandonment of cultivated lands and successive establishment of natural vegetation led to carbon (C) accumulation in soil, qualitative changes in organic C pools and microbial community. This study was aimed (1) to quantify the different C organic pools (total, labile, recalcitrant, and microbial) in the former arable Chernozems depending on the abandonment period and (2) to estimate C sequestration potential of soils after land use change from crops to natural vegetation. Our investigations were carried out on arable soil under winter wheat and soils abandoned 5, 11, 21 and 77 years ago after land use change from crops to permanent grassland (Haplic Chernozems, Rostov region, Russia, 47o27'N, 39o35'E). The total soil organic C (Ctotal, dichromate oxidation method), labile and recalcitrant C (after 7 week incubation at 20 oC and 60% of water holding capacity) were determined in the former plough-layer (0-20 cm). A first order two-component model was used for the analysis of cumulative CO2-C evolution, calculation of mineralization rate constants for labile and recalcitrant C-pools, and estimation of their mean residence time (MRT). Carbon immobilized in microbial biomass (Cmic) was estimated by fumigation-extraction method before and after 10 weeks of incubation without and following addition of glucose at rate of 730 μg/g of soil. Carbon sequestration potential of soils (CSP, %) was calculated using the ratio between extra C-CO2 release induced by glucose addition and amount of C applied to soil. Our results showed that the establishment of perennial vegetation after land use change from arable Chernozems to permanent grassland resulted in the significant C-accumulation in soils. The SOC-content (0-20 cm layer) increased from 2.08±0.03 to 2.24±0.04% for the first 5

  3. Estimation of Carbon Dioxide Storage Capacity for Depleted Gas Reservoirs

    NASA Astrophysics Data System (ADS)

    Lai, Yen Ting; Shen, Chien-Hao; Tseng, Chi-Chung; Fan, Chen-Hui; Hsieh, Bieng-Zih

    2015-04-01

    A depleted gas reservoir is one of the best options for CO2 storage for many reasons. First of all, the storage safety or the caprock integrity has been proven because the natural gas was trapped in the formation for a very long period of time. Also the formation properties and fluid flow characteristics for the reservoir have been well studied since the discovery of the gas reservoir. Finally the surface constructions and facilities are very useful and relatively easy to convert for the use of CO2 storage. The purpose of this study was to apply an analytical approach to estimate CO2 storage capacity in a depleted gas reservoir. The analytical method we used is the material balance equation (MBE), which have been widely used in natural gas storage. We proposed a modified MBE for CO2 storage in a depleted gas reservoir by introducing the z-factors of gas, CO2 and the mixture of the two. The MBE can be derived to a linear relationship between the ratio of pressure to gas z-factor (p/z) and the cumulative term (Gp-Ginj, where Gp is the cumulative gas production and Ginj is the cumulative CO2 injection). The CO2 storage capacity can be calculated when constraints of reservoir recovery pressure are adopted. The numerical simulation was also used for the validation of the theoretical estimation of CO2 storage capacity from the MBE. We found that the quantity of CO2 stored is more than that of gas produced when the reservoir pressure is recovered from the abandon pressure to the initial pressure. This result was basically from the fact that the gas- CO2 mixture z-factors are lower than the natural gas z-factors in reservoir conditions. We also established a useful p/z plot to easily observe the pressure behavior of CO2 storage and efficiently calculate the CO2 storage capacity. The application of the MBE we proposed was demonstrated by a case study of a depleted gas reservoir in northwestern Taiwan. The estimated CO2 storage capacities from conducting reservoir simulation

  4. Carbon Storage in Biologic and Oceanic Reservoirs: Issues and Opportunities

    NASA Astrophysics Data System (ADS)

    Caldeira, K.

    2007-12-01

    Most discussion of carbon capture and storage have focused on geologic reservoirs because these are the reservoirs most likely to provide for long-term storage with a minimum of adverse environmental consequences. Nevertheless, there is interest in storage in other reservoirs such as the biosphere or the oceans. Storage in biological reservoirs such as forests or agricultural soils may in many cases be relatively inexpensive. Because this biological storage involves carbon dioxide removal from the atmosphere, it can potentially offset emissions from the transportation sector. Biological storage can be politically popular because it can be deployed with simple technologies, can be deployed in developing countries, and in many cases involves other environmental co-benefits. However, total capacity is limited. Furthermore, biological storage is temporary unless the store is actively maintained forever. Such temporary storage can be valuable, although it is clearly not as valuable as the quasi-permanent storage offered by good geologic storage reservoirs Ocean storage options fall into two main classes. The first involves conventional separation and compression of carbon dioxide from large point sources which would then be piped into the deep ocean and released either into the water or as a lake on the sea floor. In either case, the carbon dioxide would eventually interact with the atmosphere and contribute to ocean acidification. However, there is potential for the development of long-term engineered containment of carbon dioxide on or in the sea floor. The second main ocean storage option involves increasing ocean alkalinity, probably by dissolving carbonate minerals. This approach may offer safe, quasi- permanent, and cost-effective storage in settings where coastal carbon dioxide point sources are co-located with carbonate mineral deposits. Not every location or carbon dioxide source is suitable for geologic storage of carbon dioxide. At this early stage, it is

  5. CO2 Huff-n-Puff Process in a Light Oil Shallow Shelf Carbonate Reservoir

    SciTech Connect

    John Prieditis; Mark Kovar; Roger Cole; Scott Wehner

    1998-02-02

    The principal objective of the Sundown Slaughter Unit (SSU) CO2 Huff- n- Puff (H- n- P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. Sundown Slaughter Unit is the second demonstration site associated with this project, following the unsuccessful test at Central Vacuum Unit. The ultimate goal will be to develop guidelines based on commonly available data that other operators in the industry can use to investigate the applicability of the process within other fields. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of Energy's (DOE) objective of increasing domestic oil production and deferring the abandonment of shallow shelf carbonate (SSC) reservoirs. Tasks associated with this objective are carried out in what is a timely effort for near- term goals. The goal of this Sundown Slaughter Unit Project is to demonstrate the CO2 Huff- n- Puff process in a waterflooded, light oil, shallow shelf carbonate reservoir within the Permian Basin. The CO2 Huff- n- Puff process is a proven enhanced oil recovery technology for Louisiana- Texas gulf coast sandstone reservoirs. The reader is referred to three Society of Petroleum Engineer (SPE) papers, No. 15502, No. 16720 & No. 20208 for a review of the theory, mechanics of the process, and several case histories. The process has even been shown to be moderately effective in conjunction with steam on heavy California crude oils. Although the technology is proven in gulf coast sandstones, it continues to be a very underutilized enhanced recovery option for carbonates. The goal of this technology demonstration is to gain an overall understanding of the reservoir qualities that influence CO2 Huff- n- Puff production responses within a heterogeneous reservoir such as the shallow shelf carbonate environment of the Sundown Slaughter Unit. A generalized

  6. Organic carbon burial efficiency in a subtropical hydroelectric reservoir

    NASA Astrophysics Data System (ADS)

    Mendonça, Raquel; Kosten, Sarian; Sobek, Sebastian; Jaqueline Cardoso, Simone; Figueiredo-Barros, Marcos Paulo; Henrique Duque Estrada, Carlos; Roland, Fábio

    2016-06-01

    Hydroelectric reservoirs bury significant amounts of organic carbon (OC) in their sediments. Many reservoirs are characterized by high sedimentation rates, low oxygen concentrations in bottom water and a high share of terrestrially derived OC, and all of these factors have been linked to a high efficiency of OC burial. However, investigations of OC burial efficiency (OCBE, i.e., the ratio between buried and deposited OC) in reservoirs are limited to a few studies, none of which include spatially resolved analyses. In this study we determined the spatial variation in OCBE in a large subtropical reservoir and related it to sediment characteristics. Our results show that the sediment accumulation rate explains up to 92 % of the spatial variability in OCBE, outweighing the effect of other variables, such as OC source and oxygen exposure time. OCBE at the pelagic sites varied from 48 to 86 % (mean 67 %) and decreased towards the dam. At the margins, OCBE was lower (9-17 %) due to the low sediment accumulation in shallow areas. Our data show that the variability in OCBE both along the rivers-dam and the margin-pelagic axes must be considered in whole-reservoir assessments. Combining these results with a spatially resolved assessment of sediment accumulation and OC burial in the studied reservoir, we estimated a spatially resolved mean OC burial efficiency of 57 %. Being the first assessment of OCBE with such a high spatial resolution in a reservoir, these results suggest that reservoirs may bury OC more efficiently than natural lakes.

  7. Soil carbon sequestration due to post-Soviet cropland abandonment: estimates from a large-scale soil organic carbon field inventory.

    PubMed

    Wertebach, Tim-Martin; Hölzel, Norbert; Kämpf, Immo; Yurtaev, Andrey; Tupitsin, Sergey; Kiehl, Kathrin; Kamp, Johannes; Kleinebecker, Till

    2017-02-04

    The break-up of the Soviet Union in 1991 triggered cropland abandonment on a continental scale, which in turn led to carbon accumulation on abandoned land across Eurasia. Previous studies have estimated carbon accumulation rates across Russia based on large-scale modelling. Studies that assess carbon sequestration on abandoned land based on robust field sampling are rare. We investigated soil organic carbon (SOC) stocks using a randomized sampling design along a climatic gradient from forest steppe to Sub-Taiga in Western Siberia (Tyumen Province). In total, SOC contents were sampled on 470 plots across different soil and land-use types. The effect of land use on changes in SOC stock was evaluated, and carbon sequestration rates were calculated for different age stages of abandoned cropland. While land-use type had an effect on carbon accumulation in the topsoil (0-5 cm), no independent land-use effects were found for deeper SOC stocks. Topsoil carbon stocks of grasslands and forests were significantly higher than those of soils managed for crops and under abandoned cropland. SOC increased significantly with time since abandonment. The average carbon sequestration rate for soils of abandoned cropland was 0.66 Mg C ha(-1)  yr(-1) (1-20 years old, 0-5 cm soil depth), which is at the lower end of published estimates for Russia and Siberia. There was a tendency towards SOC saturation on abandoned land as sequestration rates were much higher for recently abandoned (1-10 years old, 1.04 Mg C ha(-1)  yr(-1) ) compared to earlier abandoned crop fields (11-20 years old, 0.26 Mg C ha(-1)  yr(-1) ). Our study confirms the global significance of abandoned cropland in Russia for carbon sequestration. Our findings also suggest that robust regional surveys based on a large number of samples advance model-based continent-wide SOC prediction.

  8. Carbon dioxide concentration dictates alternative methanogenic pathways in oil reservoirs.

    PubMed

    Mayumi, Daisuke; Dolfing, Jan; Sakata, Susumu; Maeda, Haruo; Miyagawa, Yoshihiro; Ikarashi, Masayuki; Tamaki, Hideyuki; Takeuchi, Mio; Nakatsu, Cindy H; Kamagata, Yoichi

    2013-01-01

    Deep subsurface formations (for example, high-temperature oil reservoirs) are candidate sites for carbon capture and storage technology. However, very little is known about how the subsurface microbial community would respond to an increase in CO2 pressure resulting from carbon capture and storage. Here we construct microcosms mimicking reservoir conditions (55 °C, 5 MPa) using high-temperature oil reservoir samples. Methanogenesis occurs under both high and low CO2 conditions in the microcosms. However, the increase in CO2 pressure accelerates the rate of methanogenesis to more than twice than that under low CO2 conditions. Isotope tracer and molecular analyses show that high CO2 conditions invoke acetoclastic methanogenesis in place of syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis that typically occurs in this environment (low CO2 conditions). Our results present a possibility of carbon capture and storage for enhanced microbial energy production in deep subsurface environments that can mitigate global warming and energy depletion.

  9. How do soil organic carbon stocks change after cropland abandonment in Mediterranean humid mountain areas?

    PubMed

    Nadal-Romero, E; Cammeraat, E; Pérez-Cardiel, E; Lasanta, T

    2016-10-01

    The effects of land use changes on soil carbon stocks are a matter of concern stated in international policy agendas on the mitigation of greenhouse emissions. Afforestation is increasingly viewed as an environmental restorative land use change prescription and is considered one of the most efficient carbon sequestration strategies currently available. Given the large quantity of CO2 that soils release annually, it is important to understand disturbances in vegetation and soil resulting from land use changes. The main objective of this study is to assess the effects of land abandonment, land use change and afforestation practices on soil organic carbon (SOC) dynamics. For this aim, five different land covers (bare soil, permanent pastureland, secondary succession, Pinus sylvestris (PS) and Pinus nigra (PN) afforestation), in the Central Spanish Pyrenees, were analysed. SOC dynamics have been studied in the bulk soil, and in the fractions separated according to two methodologies: (i) aggregate size distribution, and (ii) density fractionation, and rates of carbon mineralization have been determined by measuring CO2 evolution using an automated respirometer. The results showed that: (i) SOC contents were higher in the PN sites in the topsoil (10cm), (ii) when all the profiles were considered no significant differences were observed between pastureland and PN, (iii) SOC accumulation under secondary succession is a slow process, and (iv) pastureland should also be considered due to the relative importance in SOC stocks. The first step of SOC stabilization after afforestation is the formation of macro-aggregates promoted by large inputs of SOC, with a high contribution of labile organic matter. However, our respiration experiments did not show evidence of SOC stabilization. SOC mineralization was higher in the top layers and values decreased with depth. These results gain insights into which type of land management is most appropriate after land abandonment for SOC.

  10. CARVE: The Carbon in Arctic Reservoirs Vulnerability Experiment

    NASA Technical Reports Server (NTRS)

    Miller, Charles E.; Dinardo, Steven J.

    2012-01-01

    The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) is a NASA Earth Ventures (EV-1) investigation designed to quantify correlations between atmospheric and surface state variables for the Alaskan terrestrial ecosystems through intensive seasonal aircraft campaigns, ground-based observations, and analysis sustained over a 5-year mission. CARVE bridges critical gaps in our knowledge and understanding of Arctic ecosystems, linkages between the Arctic hydrologic and terrestrial carbon cycles, and the feedbacks from fires and thawing permafrost. CARVE's objectives are to: (1) Directly test hypotheses attributing the mobilization of vulnerable Arctic carbon reservoirs to climate warming; (2) Deliver the first direct measurements and detailed maps of CO2 and CH4 sources on regional scales in the Alaskan Arctic; and (3) Demonstrate new remote sensing and modeling capabilities to quantify feedbacks between carbon fluxes and carbon cycle-climate processes in the Arctic (Figure 1). We describe the investigation design and results from 2011 test flights in Alaska.

  11. CARVE: The Carbon in Arctic Reservoirs Vulnerability Experiment

    NASA Technical Reports Server (NTRS)

    Miller, Charles E.; Dinardo, Steven J.

    2012-01-01

    The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) is a NASA Earth Ventures (EV-1) investigation designed to quantify correlations between atmospheric and surface state variables for the Alaskan terrestrial ecosystems through intensive seasonal aircraft campaigns, ground-based observations, and analysis sustained over a 5-year mission. CARVE bridges critical gaps in our knowledge and understanding of Arctic ecosystems, linkages between the Arctic hydrologic and terrestrial carbon cycles, and the feedbacks from fires and thawing permafrost. CARVE's objectives are to: (1) Directly test hypotheses attributing the mobilization of vulnerable Arctic carbon reservoirs to climate warming; (2) Deliver the first direct measurements and detailed maps of CO2 and CH4 sources on regional scales in the Alaskan Arctic; and (3) Demonstrate new remote sensing and modeling capabilities to quantify feedbacks between carbon fluxes and carbon cycle-climate processes in the Arctic (Figure 1). We describe the investigation design and results from 2011 test flights in Alaska.

  12. Effect of land abandonment on soil organic carbon fractions along a precipitation gradient in Mediterranean conditions

    NASA Astrophysics Data System (ADS)

    Gabarron-Galeote, Miguel A.; Trigalet, Sylvain; van Wesemael, Bas

    2015-04-01

    Land abandonment has been the main land use change in rural European Mediterranean areas over the last decades. The secondary succession process following land abandonment is strongly affected by precipitation, which in consequence determines the parallel change of soil organic carbon (SOC) and other soil properties. SOC is usually assumed to increase due to the intensification of plant residues inputs to soil, above as well below ground. However, SOC is composed of different fractions with contrasting resistance to decomposition that can have different responses to land abandonment. The objectives of this study are: i) to determine the net effect of land abandonment on the different soil organic carbon fractions; ii) to assess the relation between vegetation evolution and SOC fractions; iii) to establish the conditions with the greater potential to store stable SOC along a precipitation gradient. Three field sites with contrasting annual precipitation (GAU: 1080.5 mm yr-1- ALM: 650 mm yr-1- GER: 350 mm yr-1) were selected. On each site Fields abandoned in different periods, as verified on aerial photographs taken in 1956, 1977, 1984, 1998, 2001, 2004 and 2009, were selected using a chronosequence approach. The fractionation protocol implemented was based on the separation of different soil particle sizes, which are associated to SOC pools with different degree of stability. Samples of the first 10 cm of soil were added to a sodium-hexametaphosphate (HMP) solution (40 g L-1) and shaken horizontally for 1h (150 r.p.m.). The soil solution was then sieved consecutively through two meshes of 250 µm and 50 µm, obtaining the following fractions: i) >250 µm (coarse fraction), it contains coarse particles (coarse sand) and plant residues (particulate organic matter, POM), easily decomposable, that constitute the more labile SOC pool; ii) 50 - 250 µm (mid fraction), it contains fine sand, fine POM easily decomposable and stable microaggregates, that contains SOC

  13. Dynamics of soil organic carbon and nitrogen following agricultural abandonment in a karst region

    NASA Astrophysics Data System (ADS)

    Li, Dejun; Wen, Li; Yang, Liqiong; Luo, Pan; Xiao, Kongcao; Chen, Hao; Zhang, Wei; He, Xunyang; Chen, Hongsong; Wang, Kelin

    2017-01-01

    Agricultural abandonment is regarded as a major driver of soil organic carbon (C) dynamics, but the mechanisms underlying the direction and magnitude of soil C dynamics following agricultural abandonment are poorly understood. Here dynamics of soil C and N contents during postagricultural succession were investigated in areas underlain by dolomite or limestone by using a space-for-time substitution approach in a karst region, southwest China. One hundred twenty-five sites from cropland, grassland, shrubland, and secondary forest were selected to represent different succession stages. Overall, soil C and N contents were greater (P < 0.05) over limestone than over dolomite mainly due to significantly greater contents of soil C and N in the cropland and grassland underlain by limestone. Both soil C and N contents were lowest in the cropland while highest in the forest. Further analysis indicated that the patterns of soil C and N dynamics differed between the two lithology types. Soil C and N contents increased significantly from cropland to forest over dolomite, while varied insignificantly among succession stages over limestone. Exchangeable calcium explained most of soil C and N variance. We proposed that higher dissolution rate of limestone could replenish the lost calcium so that the calcium levels, and in turn soil C and N contents, were stable from the cropland to the forest. Nevertheless, due to relatively low dissolution rate for dolomite, the calcium level was depleted in the cropland. Following agricultural abandonment, calcium level recovered due to decreased loss, which in turn resulted in recovery of soil C and N.

  14. Electrolyte reservoir for carbonate fuel cells

    DOEpatents

    Iacovangelo, C.D.; Shores, D.A.

    1984-05-23

    An electrode for a carbonate fuel cell and method of making same are described wherein a substantially uniform mixture of an electrode-active powder and porous ceramic particles suitable for a carbonate fuel cell are formed into an electrode with the porous ceramic particles having pores in the range of from about 1 micron to about 3 microns, and a carbonate electrolyte is in the pores of the ceramic particles.

  15. Electrolyte reservoir for carbonate fuel cells

    DOEpatents

    Iacovangelo, Charles D.; Shores, David A.

    1985-01-01

    An electrode for a carbonate fuel cell and method of making same wherein a substantially uniform mixture of an electrode-active powder and porous ceramic particles suitable for a carbonate fuel cell are formed into an electrode with the porous ceramic particles having pores in the range of from about 1 micron to about 3 microns, and a carbonate electrolyte is in the pores of the ceramic particles.

  16. Carbonate reservoir plays in the South Atlantic and worldwide analogs

    NASA Astrophysics Data System (ADS)

    Mohriak, Webster

    2015-04-01

    This work presents a summary of the geological, geophysical and petrophysical challenges for interpretation of post-salt and presalt carbonate rocks that constitute one of the main reservoirs in the hydrocarbon accumulations in the South Atlantic, particularly in the Campos and Santos basins offshore Brazil and in the Angola -Gabon conjugate margins. Carbonate rocks associated with salt tectonics constitute one of the main exploratory plays in several basins worldwide, and recently have yielded large petroleum discoveries in the southeastern Brazilian continental margin (Santos Basin) and also in Angola (Kwanza Basin) . The presalt microbialite reservoirs are sealed by evaporites and the origin of these rocks is still controversial. One current of interpretation assumes they are associated with reefs and carbonate buildups formed during periods of sea-level rises in a desiccating basin. Other currents of interpretation assume that these rocks might be associated with hydrothermal fluids and chemical precipitation of carbonates in a basin affected by volcanic episodes, resulting in travertine deposits with secondary biogenic growth. We present examples of post-salt oil fields involving Albian carbonates in the South Atlantic, and also discuss the presalt plays recently drilled in ultradeep waters. The presalt carbonate reservoirs are compared with possible microbialite analogs in the sedimentary basins of Brazil dating from Neoproterozoic to Recent, and their similarities and differences in terms of depositional setting and petrophysical parameters from the Late Aptian presalt carbonate rocks that have been sampled in the Santos and Kwanza basins.

  17. Calculation of petrophysical properties for Mishrif carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Kadhim, Fadhil Sarhan; Samsuri, Ariffin; Idris, Ahmad Kamal

    2014-10-01

    The accurate calculations of petrophysical properties in carbonate reservoirs are the most challenging aspects of well log analysis. Many equations have been developed over the years based on known physical principles or on empirically derived relationships, which are used to calculate carbonate rock petrophysical properties. Carbonate reservoirs in the Middle East are very heterogeneous in terms of rock types. Therefore the reservoir should be split into layers on the basis of the dominant rock type in order to define average values and trends of petrophysical parameters in the reservoir rock. The saturation exponent (n) and cementation exponent (m) are calculated from well log data using Pickett method. The study made across the Mishrif carbonate formation, which is the shallowest formation of the hydrocarbon bearing zone in the NS oil field in the Middle East. Results show that the average formation water resistivity (Rw= 0.0243), average mud filtrate resistivity (Rmf= 0.199), Irreducible Water Saturation (Swi=0. 18), and Archie's parameters (m=1. 78, n= 2, and a=1). While porosity, true resistivity, and water saturation values with depth of formation were calculated by using Interactive Petrophysics software (IP V3.5, 2008). The computer process interpretation (CPI) illustrates that the shale member splits the Mishrif formation into two parts; Upper and Lower Mishrif. This study is a step to investigate petrophysical properties, which used to calculate water saturation that should use to estimate original oil in place and detected the perforation zones.

  18. ENHANCEMENT OF TERRESTRIAL CARBON SINKS THROUGH RECLAMATION OF ABANDONED MINE LANDS IN THE APPALACHIAN REGION

    SciTech Connect

    Gary D. Kronrad

    2002-12-01

    The U.S.D.I. Office of Surface Mining (OSM) estimates that there are approximately 1 million acres of abandoned mine land (AML) in the Appalachian region. AML lands are classified as areas that were inadequately reclaimed or were left unreclaimed prior to the passage of the 1977 Surface Mining Control and Reclamation Act, and where no federal or state laws require any further reclamation responsibility to any company or individual. Reclamation and afforestation of these sites have the potential to provide landowners with cyclical timber revenues, generate environmental benefits to surrounding communities, and sequester carbon in the terrestrial ecosystem. Through a memorandum of understanding, the OSM and the U.S. Department of Energy (DOE) have decided to investigate reclaiming and afforesting these lands for the purpose of mitigating the negative effects of anthropogenic carbon dioxide in the atmosphere. This study determined the carbon sequestration potential of northern red oak (Quercus rubra L.), one of the major reclamation as well as commercial species, planted on West Virginia AML sites. Analyses were conducted to (1) calculate the total number of tons that can be stored, (2) determine the cost per ton to store carbon, and (3) calculate the profitability of managing these forests for timber production alone and for timber production and carbon storage together. The Forest Management Optimizer (FORMOP) was used to simulate growth data on diameter, height, and volume for northern red oak. Variables used in this study included site indices ranging from 40 to 80 (base age 50), thinning frequencies of 0, 1, and 2, thinning percentages of 20, 25, 30, 35, and 40, and a maximum rotation length of 100 years. Real alternative rates of return (ARR) ranging from 0.5% to 12.5% were chosen for the economic analyses. A total of 769,248 thinning and harvesting combinations, net present worths, and soil expectation values were calculated in this study. Results indicate that

  19. Distribution, origin and prediction of carbon dioxide in petroleum reservoirs

    SciTech Connect

    Thrasher, J.; Fleet, A.J.

    1995-08-01

    High concentrations of carbon dioxide (CO{sub 2}) in petroleum reservoirs can significantly reduce the value of the discovery, by diluting any hydrocarbons, and by increasing production costs because of the increased likelihood of corrosion and scale formation. Huge volumes of CO{sub 2} have been found, for example in the Indonesian Natuna d-Alpha structure (estimated 240 tcf gas, of which around 70% is CO{sub 2}). This study reviews the possible sources of CO{sub 2} in the petroleum system, and the geological and geochemical data from some CO{sub 2} {open_quotes}polluted{close_quotes} reservoirs, to improve future predictions of the exploration risk of finding significant CO{sub 2}. A number of case studies show that the most common geological circumstances for the occurrence of high concentrations of CO{sub 2} include: carbonates associated with post-trap igneous activity (e.g. Ibleo Platform, Sicily); reservoir close to hot basement (e.g. Cooper-Eromanga Basin, Australia) and deep faults close to traps (e.g. Gulf of Thailand). Less common circumstances for high proportions of CO{sub 2} in gas include: post-trap igneous activity and coals (e.g. Taranaki, New Zealand) and reservoirs associated with pre-oil window coaly kerogen (e.g. Malay Trough), although the volumes of CO{sub 2} generated from kerogen are usually low relative to volumes of hydrocarbons generated from kerogen.

  20. MULTIDISCIPLINARY IMAGING OF ROCK PROPERTIES IN CARBONATE RESERVOIRS FOR FLOW-UNIT TARGETING

    SciTech Connect

    Stephen C. Ruppel

    2005-02-01

    Despite declining production rates, existing reservoirs in the US contain large quantities of remaining oil and gas that constitute a huge target for improved diagnosis and imaging of reservoir properties. The resource target is especially large in carbonate reservoirs, where conventional data and methodologies are normally insufficient to resolve critical scales of reservoir heterogeneity. The objectives of the research described in this report were to develop and test such methodologies for improved imaging, measurement, modeling, and prediction of reservoir properties in carbonate hydrocarbon reservoirs. The focus of the study is the Permian-age Fullerton Clear Fork reservoir of the Permian Basin of West Texas. This reservoir is an especially appropriate choice considering (a) the Permian Basin is the largest oil-bearing basin in the US, and (b) as a play, Clear Fork reservoirs have exhibited the lowest recovery efficiencies of all carbonate reservoirs in the Permian Basin.

  1. Carbon dioxide concentration dictates alternative methanogenic pathways in oil reservoirs

    PubMed Central

    Mayumi, Daisuke; Dolfing, Jan; Sakata, Susumu; Maeda, Haruo; Miyagawa, Yoshihiro; Ikarashi, Masayuki; Tamaki, Hideyuki; Takeuchi, Mio; Nakatsu, Cindy H.; Kamagata, Yoichi

    2013-01-01

    Deep subsurface formations (for example, high-temperature oil reservoirs) are candidate sites for carbon capture and storage technology. However, very little is known about how the subsurface microbial community would respond to an increase in CO2 pressure resulting from carbon capture and storage. Here we construct microcosms mimicking reservoir conditions (55 °C, 5 MPa) using high-temperature oil reservoir samples. Methanogenesis occurs under both high and low CO2 conditions in the microcosms. However, the increase in CO2 pressure accelerates the rate of methanogenesis to more than twice than that under low CO2 conditions. Isotope tracer and molecular analyses show that high CO2 conditions invoke acetoclastic methanogenesis in place of syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis that typically occurs in this environment (low CO2 conditions). Our results present a possibility of carbon capture and storage for enhanced microbial energy production in deep subsurface environments that can mitigate global warming and energy depletion. PMID:23759740

  2. CO{sub 2} HUFF-n-PUFF process in a light oil shallow shelf carbonate reservoir. Quarterly technical progress report, [January 1, 1995--March 31, 1995

    SciTech Connect

    Cole, R.; Prieditis, J.; Vogt, J.; Wehner, S.

    1995-04-21

    The principal objective of the Central Vacuum Unit (CVU) CO{sub 2} Huff-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the CO{sub 2} H-n-P process, coupled with the CVU reservoir characterization components will determine if this process is technically and economically feasible for field implementation. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of Energy`s (DOE) objective of increasing domestic oil production and deferring the abandonment of shallow shelf carbonate (SSC) reservoirs. Technical progress is reported for geostatitical realizations; paramatric simulation; waterflood review; and reservoir characterization.

  3. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. Second quarterly technical progress report, [April 1995--June 1995

    SciTech Connect

    Cole, R.; Prieditis, J.; Vogt, J.; Wehner, S.

    1995-07-11

    The principal objective of the Central Vacuum Unit (CVU) CO{sub 2} Huff-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the CO{sub 2} H-n-P process, coupled with the CVU reservoir characterization components will determine if this process is technically and economically feasible for field implementation. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of Energy`s (DOE) objective of increasing domestic oil production and deferring the abandonment of shallow shelf carbonate (SSC) reservoirs. Tasks associated with this objective are carried out in what is considered a timely effort for near-term goals. Technical progress is summarized for; geostatistical realizations; site-specific simulation;waterflood review; and reservoir characterization.

  4. Carbon Sequestration in Unconventional Reservoirs: Geophysical, Geochemical and Geomechanical Considerations

    NASA Astrophysics Data System (ADS)

    Zakharova, Natalia V.

    In the face of the environmental challenges presented by the acceleration of global warming, carbon capture and storage, also called carbon sequestration, may provide a vital option to reduce anthropogenic carbon dioxide emissions, while meeting the world's energy demands. To operate on a global scale, carbon sequestration would require thousands of geologic repositories that could accommodate billions of tons of carbon dioxide per year. In order to reach such capacity, various types of geologic reservoirs should be considered, including unconventional reservoirs such as volcanic rocks, fractured formations, and moderate-permeability aquifers. Unconventional reservoirs, however, are characterized by complex pore structure, high heterogeneity, and intricate feedbacks between physical, chemical and mechanical processes, and their capacity to securely store carbon emissions needs to be confirmed. In this dissertation, I present my contribution toward the understanding of geophysical, geochemical, hydraulic, and geomechanical properties of continental basalts and fractured sedimentary formations in the context of their carbon storage capacity. The data come from two characterization projects, in the Columbia River Flood Basalt in Washington and the Newark Rift Basin in New York, funded by the U.S. Department of Energy through Big Sky Carbon Sequestration Partnerships and TriCarb Consortium for Carbon Sequestration. My work focuses on in situ analysis using borehole geophysical measurements that allow for detailed characterization of formation properties on the reservoir scale and under nearly unaltered subsurface conditions. The immobilization of injected CO2 by mineralization in basaltic rocks offers a critical advantage over sedimentary reservoirs for long-term CO2 storage. Continental flood basalts, such as the Columbia River Basalt Group, possess a suitable structure for CO2 storage, with extensive reservoirs in the interflow zones separated by massive impermeable

  5. Vertical stacking of reservoirs in Silurian carbonates of Appalachian basin

    SciTech Connect

    Smosna, R.; Conrad, J.M.; Maxwell, T.C.

    1988-08-01

    The distribution of modern reefs and oolites is controlled to a large degree by sea-floor topography. Likewise, paleotopographic highs in the Silurian Lockport Dolomite and underlying Keefer Sandstone provided optimum sites for the deposition of boundstone and grainstone reservoir facies. The Keefer Sandstone in western West Virginia was deposited as a series of subtidal sand waves with a relief of a few meters. During initial Lockport sedimentation, the turbulence, water chemistry, and light intensity were most favorable in shallow water over the Keefer sand waves, encouraging growth of coral-stromatoporoid patch reefs. Skeletal banks in the upper Lockport of eastern Kentucky also were established over topographic highs of earlier Lockport mounds. In a similar fashion, the upper Lockport of West Virginia was deposited as oolitic shoals that formed atop exposed mud mounds in the middle member. A slight rise of sea level created the agitated subtidal environment above the now-submerged mud mounds, and oolite bars developed. The reef, skeletal-bank, and oolite facies of the Lockport, and the Keefer Sandstone, are all petroleum reservoirs. Carbonate reservoirs can be identified in the subsurface by thicks on isopach maps, by their clean gamma-ray signature, and by a relatively high log porosity. Based on these criteria, seven potential fairways have been mapped in Kentucky. Because the distribution of buildups was greatly influenced by that of their predecessors, five of the fairways contain vertically stacked reservoir facies. These are particularly attractive because they can be drilled as multistory targets.

  6. Carbonate reservoirs at the Mesozoic-Tertiary unconformity, northeast Spain

    SciTech Connect

    Esteban, M.

    1988-08-01

    Carbonates at the Mesozoic-Tertiary unconformity in northeast Spain show four types/stages of evolution of reservoir properties: karstification, coastal reworking, Miocene organic buildups, and Pliocene burial. Subaerial exposure during Paleogene-early Miocene rifting developed a complex fracture-controlled paleokrast facies, showing up to three evolution levels with well-developed cavern and vuggy porosity (1). During the Miocene, the paleokrast profile was intensively reworked into a variety of breccias, conglomerates, and calcarenites in both alluvial and coastal depositional settings. Gravitational displacement of largely karstified hillsides was common. These reworked paleokarst deposits (2) present excellent reservoir properties. The Miocene formations onlap the karstified Mesozoic and the reworked facies; these formations include coral reefs and foramalgal buildups (3) with primary and secondary porosity. Finally, a late fracture event (attributed to the Pliocene) affected the buried and lithified paleokarst deposits and lower-middle Miocene formations (4). This fracture event is associated with vuggy corrosion, dolomitization, ore mineralization, and leaching of Mesozoic to middle Miocene carbonates. Several horizons with chalky microporosity are also tentatively related to this Pliocene event. These four phases of reservoir evolution are also recognized in northern Morocco and southern Italy.

  7. Wellbore stability analysis during the production of a carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Alves, J.-L.; Coehlo, L.; Baud, P.; Guevara Junior, N.

    2009-04-01

    Carbonate reservoirs represent a major part of the world oil and gas reserves. During production, the extraction of hydrocarbons reduces pore pressure and thus causes an increase in the effective stress and mechanical compaction in the reservoir. The compactive deformation and failure may be spatially extensive or localized to the vicinity of the wellbore, but in either case the consequences can be economically severe involving surface subsidence, well failure and various production problems. The analysis of wellbore stability and more generally of deformation and failure in carbonate environments hinges upon a relevant constitutive modeling of carbonate rocks over a wide range of porosities. In this study, we performed a wellbore stability analysis for a lateral wellbore junction in three dimensions. The complex geometry for the wellbore junction was modeled with tetrahedral finite elements considering a rate independent elastic-plastic isotropic material that presented linear behavior during elastic strain and associated flow rule. A finite element model simulating drilling and production phases were done for field conditions from a deep water reservoir in Campos basin, offshore Brazil. In this context, several scenarios were studied considering true 3D orientation for both in situ stresses and geometry of the wellbore junction itself. We discussed the impact of constitutive modeling on the wellbore stability, based on new experimental data on two micritic porous carbonates. Series of conventional triaxial experiments were performed at room temperature in dry and wet conditions on samples of Comiso and Tavel limestones of respective porosity 17 and 16%. The wet samples were deformed in drained conditions with 10 MPa pore pressure. The initial yield stresses were identified as the critical stresses at the onset of shear-enhanced compaction, subsequent yield stresses were considered to depend on hardening given by the plastic volumetric strain. For both limestones

  8. Characterization of diagenetically altered carbonate reservoirs, South Cowden Grayburg Reservoir, West Texas

    SciTech Connect

    Lucia, F.J.; Ruppel, S.C.

    1996-12-31

    Much of the difficulty in constructing carbonate reservoir models for fluid-flow simulation results from diagenetic overprinting of depositional permeability patterns. In the South Cowden field, diagenetic effects result in (1) low porosity and permeability in the western and northern areas due to reduction of porosity by means of dolomitization and post-dolomitization compaction, (2) elimination of the petrophysical effects of depositional texture resulting from changes in particle size due to dolomitization, and (3) creation of a touching-vug pore system due to anhydrite dissolution. The extent of anhydrite alteration can be mapped to show three distinct diagenetic areas: those dominated by unaltered, altered, or dissolved anhydrite. Each alteration type has a unique acoustic-porosity transform that can be used to map the diagenetic areas and to calculate porosity when only acoustic logs are available. A single porosity-permeability transform characterizes the areas having unaltered and altered anhydrite, and the depositional stratigraphy is useful in constructing a reservoir model. A more favorable transform characterizes the area of dissolved anhydrite, and depositional stratigraphy is not useful in constructing a reservoir model because of the large effect of the diagenetic overprint.

  9. Superimposed multiple orders of sequences predict reservoir migration and thickness in stratigraphy trapped Haynesville carbonate reservoirs

    SciTech Connect

    Neuhart, D.; Hwang, D. )

    1991-08-01

    The Upper Jurassic Haynesville Formation is part of the Louark group located on the east flank of the East Texas salt basin. Haynesville gas production is from ooid grainstones which formed on a gently dipping carbonate ramp. Hydrocarbon was sourced from the underlying Smackover Formation basinal deposits and trapped stratigraphically by multiple ooid shoal pinch-outs. Therefore, an essential tool in prospecting for Haynesville gas is an understanding of Haynesville stratigraphy. Toward that end, the authors placed the formation into a sequence stratigraphic framework. Haynesville stratal-stacking patterns and lithology distribution result from the superimposition of three orders of cyclicity. Evidence of second order, third order, and fourth order sequences are found within the Haynesville data. The entire Haynesville Formation lies within a second-order transgressive systems tract, which is expresses in facies as an overall deepening event. The superimposition of second-order extreme retrograde deposition during periods of in-phase second- and third- order transgression. The results were large shifts in deposition centers and additional reservoir thickness due to increased accommodation. Fourth -order sequences exerted the greatest control an ooid reservoir distribution due to shoal progradation. By superimposing the observed multiple orders of sequences into the Haynesville geologic model, the top of Haynesville becomes both a sequence boundary in the third order and a maximum flooding surface in the second order. Together, fourth-order flooding surface in the second order. Together, fourth-order and third order sequences indicate the direction of reservoir migration as well as areas of maximum reservoir thickness.

  10. Effect of trans-reservoir water supply on carbon and nitrogen stable isotope composition in hydrologically connected reservoirs in China

    NASA Astrophysics Data System (ADS)

    Zhang, Huajun; Peng, Liang; Gu, Binhe; Han, Bo-Ping

    2017-09-01

    Dajingshan, Fenghuangshan and Meixi reservoirs are located in Zhuhai, a coastal city in southern China, and they function to supply drinking water to Zhuhai and Macau. For effectively supplying waster, they are hydrologically connected and Dajingshan Reservoir first receives the water pumped from the river at Guangchang Pumping Station, and then feeds Fenghuangshan Reservoir, and the two well-connected reservoirs are mesotrophic. Meixi Reservoir is a small and oligotrophic water body and feeds Dajingshan Reservoir only in wet seasons when overflow occurs. Particulate organic matter (POM) was collected from three hydrologically connected water supply reservoirs, and seasonal variations of POM were ascertained from stable carbon and nitrogen isotopes in wet and dry seasons, and the effects of pumping water and reservoir connectivity on POM variations and composition were demonstrated by the relationships of the stable isotope ratios of POM. Seasonality and similarity of stable carbon and nitrogen isotopes of POM varied with hydrodynamics, connectivity and trophic states of the four studied water bodies. The two well-connected reservoirs displayed more similar seasonality for δ13CPOM than those between the river station and the two reservoirs. However, the opposite seasonality appeared for δ15NPOM between the above waters and indicates different processes affecting the stable carbon and nitrogen isotopes of POM. δ13CPOM and δ15NPOM changed little between wet and dry seasons in Meixi Reservoir-a low productive and rain-driven system, suggesting little POM response to environmental changes in that water system. As expected, connectivity enhanced the similarity of the stable isotope ratios of POM between the water bodies.

  11. Effect of trans-reservoir water supply on carbon and nitrogen stable isotope composition in hydrologically connected reservoirs in China

    NASA Astrophysics Data System (ADS)

    Zhang, Huajun; Peng, Liang; Gu, Binhe; Han, Bo-Ping

    2016-10-01

    Dajingshan, Fenghuangshan and Meixi reservoirs are located in Zhuhai, a coastal city in southern China, and they function to supply drinking water to Zhuhai and Macau. For effectively supplying waster, they are hydrologically connected and Dajingshan Reservoir first receives the water pumped from the river at Guangchang Pumping Station, and then feeds Fenghuangshan Reservoir, and the two well-connected reservoirs are mesotrophic. Meixi Reservoir is a small and oligotrophic water body and feeds Dajingshan Reservoir only in wet seasons when overflow occurs. Particulate organic matter (POM) was collected from three hydrologically connected water supply reservoirs, and seasonal variations of POM were ascertained from stable carbon and nitrogen isotopes in wet and dry seasons, and the effects of pumping water and reservoir connectivity on POM variations and composition were demonstrated by the relationships of the stable isotope ratios of POM. Seasonality and similarity of stable carbon and nitrogen isotopes of POM varied with hydrodynamics, connectivity and trophic states of the four studied water bodies. The two well-connected reservoirs displayed more similar seasonality for δ13CPOM than those between the river station and the two reservoirs. However, the opposite seasonality appeared for δ15NPOM between the above waters and indicates different processes affecting the stable carbon and nitrogen isotopes of POM. δ13CPOM and δ15NPOM changed little between wet and dry seasons in Meixi Reservoir-a low productive and rain-driven system, suggesting little POM response to environmental changes in that water system. As expected, connectivity enhanced the similarity of the stable isotope ratios of POM between the water bodies.

  12. The accumulation of organic carbon in mineral soils by afforestation of abandoned farmland.

    PubMed

    Wei, Xiaorong; Qiu, Liping; Shao, Mingan; Zhang, Xingchang; Gale, William J

    2012-01-01

    The afforestation of abandoned farmland significantly influences soil organic carbon (OC). However, the dynamics between OC inputs after afforestation and the original OC are not well understood. To learn more about soil OC dynamics after afforestation of farmland, we measured the soil OC content in paired forest and farmland plots in Shaanxi Province, China. The forest plots had been established on farmland 18, 24, 48, 100, and 200 yr previously. The natural (13)C abundance of soil organic matter was also analyzed to distinguish between crop- and forest-derived C in the afforested soils. We observed a nonlinear accumulation of total OC in the 0-80 cm depth of the mineral soil across time. Total soil OC accumulated more rapidly under forest stands aged 18 to 48 yr than under forest stands aged 100 or 200 yrs. The rate of OC accumulation was also greater in the 0-10 cm depth than in the 10-80 cm depth. Forest-derived OC in afforested soils also accumulated nonlinearly across time, with the greatest increase in the 0-20 cm depth. Forest-derived OC in afforest soils accounted for 52-86% of the total OC in the 0-10 cm depth, 36-61% of the total OC in the 10-20 cm depth, and 11-50% of the total OC in the 20-80 cm depth. Crop-derived OC concentrations in the 0-20 cm depth decreased slightly after afforestation, but there was no change in crop-derived OC concentrations in the 20-80 cm depth. The results of our study support the claim that afforestation of farmland can sequester atmospheric CO(2) by increasing soil OC stocks. Changes in the OC stocks of mineral soils after afforestation appear to be influenced mainly by the input of forest-derived C rather than by the loss of original OC.

  13. Improved Methodology for Estimating Recovery Factor of Carbonate Reservoirs Using Geological Parameters

    NASA Astrophysics Data System (ADS)

    Park, E.; Lee, M.; Keehm, Y.; Kwon, Y. K.

    2014-12-01

    Carbonate reservoirs are highly complicated and heterogeneous than typical sandstone reservoirs, because of their depositional and diagenetic complexity. Therefore estimating the prospectiveness in an early stage of reservoir development is not an easy task. Typically we use an empirical equation, which calculates recovery factor (RF) for this assessment. Since the equation was created with reservoir parameters (porosity, water saturation, permeability, viscosity, pressure, etc.) from sandstone reservoirs, the applicability to carbonate reservoirs is questionable. We compiled 97 carbonate reservoirs and created a database with reservoir properties, geological information, and production data. First, we applied the existing empirical equation to our data and the results were disappointing: the predicted RF's was far off from actual values and correlation was also poor. We then modified the equation by adding geological parameters, such as play type, reservoir age, reservoir type, porosity type, trap information. The new equation was modelled by determining the coefficient of each parameter using least-square minimizing scheme. The modified equation estimated the recovery factor much better and more reliably. We think that the additional geological information is essential for accurate assessment of carbonate reservoirs in early stage of development, since the carbonate reservoirs show high variability and complexity by depositional and diagenetic changes. Acknowledgements: This research was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources (KIGAM) funded by the Ministry of Trade, Industry and Energy of Korea (GP2012-029).

  14. Soil Inorganic Carbon in Deserts: Active Carbon Sink or Inert Reservoir?

    NASA Astrophysics Data System (ADS)

    Monger, H. C.; Cole, D. R.

    2011-12-01

    Soil inorganic carbon is the third largest C pool in the active global carbon cycle, containing at least 800 petagrams of carbon. Although carbonate dissolution-precipitation reactions have been understood for over a century, the role of soil inorganic carbon in carbon sequestration, and in particular pedogenic carbonate, is a deceptively complex process because it involves interdependent connections among climate, plants, microorganisms, silicate minerals, soil moisture, pH, and Ca supply via rain, dust, or in situ weathering. An understanding of soil inorganic carbon as a sink or reservoir also requires examination of the system at local to continental scales and at seasonal to millennial time scales. In desert soils studied in North America, carbon isotope ratios and radiocarbon dates were measured in combination with electron microscopy, lab and field experiments with biological calcite formation, and field measurements of carbon dioxide emissions. These investigations reveal that soil inorganic carbon is both an active sink and a inert reservoir depending on the spatial and temporal scale and source of calcium.

  15. Acid Fluid-Rock Interactions with Shales Comprising Unconventional Hydrocarbon Reservoirs and with Shale Capping Carbon Storage Reservoirs: Experimental Insights

    NASA Astrophysics Data System (ADS)

    Kaszuba, J. P.; Bratcher, J.; Marcon, V.; Herz-Thyhsen, R.

    2015-12-01

    Injection of HCl is often a first stage in the hydraulic fracturing process. These acidic fluids react with marls or shales in unconventional reservoirs, reactions generally comparable to reaction between shale caprocks and acidic, carbonated formation waters in a carbon storage reservoir. Hydrothermal experiments examine acid fluid-rock interaction with 1) an unconventional shale reservoir and 2) a model shale capping a carbon storage reservoir. In the former, unconventional reservoir rock and hydraulic fracturing fluid possessing a range of ionic strengths (I = 0.01, 0.15) and initial pH values (2.5 and 7.3) reacted at 115°C and 35 MPa for 28 days. In the latter, a model carbon storage reservoir (Fe-rich dolomite), shale caprock (illite), and shale-reservoir mixture each reacted with formation water (I = 0.1 and pH 6.3) at 160°C and 25 MPa for ~15 days. These three experiments were subsequently injected with sufficient CO2 to maintain CO2 saturation in the water and allowed to react for ~40 additional days. Acidic frac fluid was rapidly buffered (from pH 2.5 to 6.2 after 38 hrs) by reaction with reservoir rock whereas the pH of near-neutral frac fluid decreased (from 7.3 to 6.9) after 47 hrs. Carbonate dissolution released Ca and Sr into solution and feldspar dissolution released SiO2 and Li; the extent of reaction was greater in the experiment containing acidic frac fluid. All three carbon storage experiments displayed a similar pH decrease of 1.5 units after the addition of CO2. The pH remained low for the duration of the experiments because the immiscible supercritical CO2 phase provided an infinite reservoir of carbonic acid that could not be consumed by reaction with the rock. In all three experiments, Ca, Fe, Mg, Mn and SO4 increase with injection, but slowly decline through termination of the experiments. This trend suggests initial dissolution followed by re-precipitation of carbonates, which can be seen in modeling and SEM results. New clay minerals

  16. Changes in Soil Carbon and Nitrogen following Land Abandonment of Farmland on the Loess Plateau, China

    PubMed Central

    Deng, Lei; Shangguan, Zhou-Ping; Sweeney, Sandra

    2013-01-01

    The revegetation of abandoned farmland significantly influences soil organic C (SOC) and total N (TN). However, the dynamics of both soil OC and N storage following the abandonment of farmland are not well understood. To learn more about soil C and N storages dynamics 30 years after the conversion of farmland to grassland, we measured SOC and TN content in paired grassland and farmland sites in the Zhifanggou watershed on the Loess Plateau, China. The grassland sites were established on farmland abandoned for 1, 7, 13, 20, and 30 years. Top soil OC and TN were higher in older grassland, especially in the 0–5 cm soil depths; deeper soil OC and TN was lower in younger grasslands (<20 yr), and higher in older grasslands (30 yr). Soil OC and N storage (0–100 cm) was significantly lower in the younger grasslands (<20 yr), had increased in the older grasslands (30 yr), and at 30 years SOC had increased to pre-abandonment levels. For a thirty year period following abandonment the soil C/N value remained at 10. Our results indicate that soil C and TN were significantly and positively correlated, indicating that studies on the storage of soil OC and TN needs to focus on deeper soil and not be restricted to the uppermost (0–30 cm) soil levels. PMID:23940793

  17. Changes in soil carbon and nitrogen following land abandonment of farmland on the Loess Plateau, China.

    PubMed

    Deng, Lei; Shangguan, Zhou-Ping; Sweeney, Sandra

    2013-01-01

    The revegetation of abandoned farmland significantly influences soil organic C (SOC) and total N (TN). However, the dynamics of both soil OC and N storage following the abandonment of farmland are not well understood. To learn more about soil C and N storages dynamics 30 years after the conversion of farmland to grassland, we measured SOC and TN content in paired grassland and farmland sites in the Zhifanggou watershed on the Loess Plateau, China. The grassland sites were established on farmland abandoned for 1, 7, 13, 20, and 30 years. Top soil OC and TN were higher in older grassland, especially in the 0-5 cm soil depths; deeper soil OC and TN was lower in younger grasslands (<20 yr), and higher in older grasslands (30 yr). Soil OC and N storage (0-100 cm) was significantly lower in the younger grasslands (<20 yr), had increased in the older grasslands (30 yr), and at 30 years SOC had increased to pre-abandonment levels. For a thirty year period following abandonment the soil C/N value remained at 10. Our results indicate that soil C and TN were significantly and positively correlated, indicating that studies on the storage of soil OC and TN needs to focus on deeper soil and not be restricted to the uppermost (0-30 cm) soil levels.

  18. Reservoir sedimentology

    SciTech Connect

    Tillman, R.W.; Weber, K.J.

    1987-01-01

    Collection of papers focuses on sedimentology of siliclastic sandstone and carbonate reservoirs. Shows how detailed sedimentologic descriptions, when combined with engineering and other subsurface geologic techniques, yield reservoir models useful for reservoir management during field development and secondary and tertiary EOR. Sections cover marine sandstone and carbonate reservoirs; shoreline, deltaic, and fluvial reservoirs; and eolian reservoirs. References follow each paper.

  19. Wellbore stability analysis in carbonate reservoir considering anisotropic behaviour

    NASA Astrophysics Data System (ADS)

    Alves, José; Guevara, Nestor; Coelho, Lucia; Baud, Patrick

    2010-05-01

    Carbonate reservoirs represent a major part of the world oil and gas reserves. In particular, recent discoveries in the pre-salt offshore Brazil place big challenges to exploration and production under high temperatures and pressures (HTHP). During production, the extraction of hydrocarbons reduces pore pressure and thus causes an increase in the effective stress and mechanical compaction in the reservoir. The compactive deformation and failure may be spatially extensive or localized to the vicinity of the wellbore, but in either case the consequences can be economically severe involving surface subsidence, well failure and various production problems. The analysis of wellbore stability and more generally of deformation and failure in carbonate environments hinges upon a relevant constitutive modeling of carbonate rocks over a wide range of porosities, in particular, observed microstructure of samples suggests anisotropic behaviour. In this study, we performed a wellbore stability analysis for a lateral wellbore junction in three dimensions. The complex geometry for the wellbore junction was modeled with tetrahedral finite elements considering a rate independent elastic-plastic isotropic material that presented linear behavior during elastic strain and associated flow rule. A finite element model simulating drilling and production phases were done for field conditions from a deep water reservoir in Campos basin, offshore Brazil. In this context, several scenarios were studied considering true 3D orientation for both in situ stresses and geometry of the wellbore junction itself. We discussed the impact of constitutive modeling, considering anisotropic ductile damage and pressure sensitiveness on the wellbore stability. Parameter values for the analysis were based based on experimental data on two micritic porous carbonates. Series of conventional triaxial experiments were performed at room temperature in dry and wet conditions on samples of Comiso and Tavel

  20. An Integrated Approach to Predicting Carbon Dioxide Storage Capacity in Carbonate Reservoirs

    NASA Astrophysics Data System (ADS)

    Smith, M. M.; Hao, Y.; Mason, H. E.; Carroll, S.

    2015-12-01

    Carbonate reservoirs are widespread globally but pose unique challenges for geologic carbon dioxide (CO2) storage due to the reactive nature of carbonate minerals and the inherently heterogeneous pore structures of these rock types. Carbonate mineral dissolution resulting from CO2-acidified fluids may actually create new storage capacity, but predicting the extent and location of enhanced storage is complicated by the presence of pore size distributions spanning orders of magnitude as well as common microfractures. To address this issue, core samples spanning a wide range of depths and predicted permeabilities were procured from wells drilled into the Weyburn-Midale reservoir from the IEA GHG's CO2 Monitoring and Storage Project, Saskatchewan, Canada; and from the Arbuckle dolomite at the Kansas Geological Survey's South-central Kansas CO2 Project. Our approach integrated non-invasive characterization, complex core-flooding experiments, and 3-D reactive transport simulations to calibrate relevant CO2 storage relationships among fluid flow, porosity, permeability, and chemical reactivity. The resulting observations from this work permit us to constrain (and place uncertainty limits on) some of the model parameters needed for estimating evolving reservoir CO2 storage capacity. The challenge remains, however, as to how to best interpret and implement these observations at the actual reservoir scale. We present our key findings from these projects and recommendations for storage capacity predictions. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  1. Carbon pool and biomass dynamics associated with deforestation, land use, and agricultural abandonment in the neotropics.

    PubMed

    Kauffman, J Boone; Hughes, R Flint; Heider, Chris

    2009-07-01

    Current rates of deforestation and the resulting C emissions in the tropics exceed those of secondary forest regrowth and C sequestration. Changing land-use strategies that would maintain standing forests may be among the least expensive of climate change mitigation options. Further, secondary tropical forests have been suggested to have great value for their potential to sequester atmospheric C. These options require an understanding of and capability to quantify C dynamics at landscape scales. Because of the diversity of physical and biotic features of tropical forests as well as approaches and intensities of land uses within the neotropics, there are tremendous differences in the capacity of different landscapes to store and sequester C. Major gaps in our current knowledge include quantification of C pools, rates and patterns of biomass loss following land-cover change, and quantification of the C storage potential of secondary forests following abandonment. In this paper we present a synthesis and further analyses from recent studies that describe C pools, patterns of C decline associated with land use, and rates of C accumulation following secondary-forest establishment--all information necessary for climate-change mitigation options. Ecosystem C pools of Neotropical primary forests minimally range from approximately 141 to 571 Mg/ha, demonstrating tremendous differences in the capacity of different forests to store C. Most of the losses in C and nutrient pools associated with conversion occur when fires are set to remove the slashed forest to prepare sites for crop or pasture establishment. Fires burning slashed primary forests have been found to result in C losses of 62-80% of prefire aboveground pools in dry (deciduous) forest landscapes and 29-57% in wet (evergreen) forest landscapes. Carbon emissions equivalent to the aboveground primary-forest pool arise from repeated fires occurring in the first 4 to 10 years following conversion. Feedbacks of climate

  2. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. Topical report No. 1

    SciTech Connect

    Cole, R.; Prieditis, J.; Vogt, J.; Wehner, S.

    1995-10-01

    The principle objective of the Central Vacuum Unit (CVU) CO{sub 2} Huff-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the CO{sub 2} H-n-P process coupled with the CVU reservoir characterization components will determine if this process is technically and economic for field implementation. The ultimate goal will be to develop guidelines based on commonly available data that other operators in the industry can use to investigate the applicability of the process within other field. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of Energy`s objective to increasing domestic oil production and deferring the abandonment of shallow shelf carbonate reservoirs. Accomplishments to date are described in this report.

  3. CO[sub]2 huff-n-puff process in a light oil shallow shelf carbonate reservoir, quarterly technical progress report, January--March, 1997

    SciTech Connect

    Wehner, S.C., Kovar, M., Casteel, J.

    1997-03-31

    The principal objective of the Central Vacuum Unit (CVU) C0{sub 2} Huff-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the C0{sub 2} H-n-P process, coupled with the CVU reservoir characterization components will be used to determine if this process is technically and economically feasible for field implementation. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of Energy`s (DOE) objective of increasing domestic oil production and detecting the abandonment of shallow shelf carbonate (SSC) reservoirs. Tasks associated with this objective are carried out in what is considered a timely effort for near-term goals.

  4. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. Quarterly technical progress report, July--September, 1995

    SciTech Connect

    Cole, R.; Prieditis, J.; Vogt, J. Wehner, S.

    1995-10-15

    The principal objective of the Central Vacuum Unit (CVU) CO{sub 2} Huff-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the CO{sub 2} H-n-P process, coupled with the CVU reservoir characterization components will determine if this process is technically and economically feasible for field implementation. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of Energy`s (DOE) objective of increasing domestic oil production and deferring the abandonment of shallow shelf carbonate (SSC) reservoirs. Tasks associated with this objective are carried out in what is considered a timely effort for near-term goals.

  5. CO{sub 2} Hugg-n-Puff process in a light oil shallow shelf carbonate reservoir. Quarterly technical progress report, 2nd quarter 1996

    SciTech Connect

    1996-07-25

    The principal objective of the Central Vacuum Unit (CVU) CO{sub 2} Huff-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the CO{sub 2} H-n-P process, coupled with the CVU reservoir characterization components will determine if this process is technically and economically feasible for field implementation. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of Energy`s (DOE) objective of increasing domestic oil production and deferring the abandonment of shallow shelf carbonate (SSC) reservoirs. Tasks associated with this objective are carried out in what is considered a timely effort for near-term goals.

  6. Lawn soil carbon storage in abandoned residential properties: an examination of ecosystem structure and function following partial human-natural decoupling.

    PubMed

    Gough, Christopher M; Elliott, Hunter L

    2012-05-15

    Residential abandonment is on the rise in many urban areas, with unknown implications for ecosystem structure and function on land slated for partial or full restoration to native habitat. Partial decoupling of human and natural systems could reduce disturbance (e.g., trampling, recreational traffic) and modify vegetation structure in a way that alters soil carbon storage, an ecosystem function that many municipalities consider a management objective of growing importance. We quantified soil carbon percent and mass to 10 cm depth and examined vegetation structure in 50 vacant and 10 occupied residential lawns located in Richmond, VA, with the principal objective of determining whether occupancy status alters trajectories of soil carbon storage or its correspondence with household economic/demographic indicators and vegetation cover. Abandoned residential lawns supported significantly less grass cover, but these declines were largely offset by increases in emergent overstory (>1 m height) vegetation cover. Soil carbon percent and mass did not differ between lawns of occupied and abandoned residences, even though significant, but highly uncertain, increases in soil carbon mass occurred in the first decade following vacancy. Instead, all residential lawns exhibited similar significant increases in soil carbon percent and mass with increasing residence age and neighborhood affluence, the former indicating annual carbon accretion rates of 20 g m(-2). We conclude that in this early stage of vacancy, soil carbon storage is already subtly responding to declines in human intervention, with reduced soil disturbance and sustained vegetation cover in abandoned lawns playing likely roles in emerging soil carbon storage trajectories.

  7. Carbon sequestration in natural gas reservoirs: Enhanced gas recovery and natural gas storage

    SciTech Connect

    Oldenburg, Curtis M.

    2003-04-08

    Natural gas reservoirs are obvious targets for carbon sequestration by direct carbon dioxide (CO{sub 2}) injection by virtue of their proven record of gas production and integrity against gas escape. Carbon sequestration in depleted natural gas reservoirs can be coupled with enhanced gas production by injecting CO{sub 2} into the reservoir as it is being produced, a process called Carbon Sequestration with Enhanced Gas Recovery (CSEGR). In this process, supercritical CO{sub 2} is injected deep in the reservoir while methane (CH{sub 4}) is produced at wells some distance away. The active injection of CO{sub 2} causes repressurization and CH{sub 4} displacement to allow the control and enhancement of gas recovery relative to water-drive or depletion-drive reservoir operations. Carbon dioxide undergoes a large change in density as CO{sub 2} gas passes through the critical pressure at temperatures near the critical temperature. This feature makes CO{sub 2} a potentially effective cushion gas for gas storage reservoirs. Thus at the end of the CSEGR process when the reservoir is filled with CO{sub 2}, additional benefit of the reservoir may be obtained through its operation as a natural gas storage reservoir. In this paper, we present discussion and simulation results from TOUGH2/EOS7C of gas mixture property prediction, gas injection, repressurization, migration, and mixing processes that occur in gas reservoirs under active CO{sub 2} injection.

  8. Investigating physical controls on methane and carbon dioxide fluxes over reservoirs using the eddy covariance method

    EPA Science Inventory

    Reservoirs are a globally important source of carbon to the atmosphere. Several recent studies have found that both carbon dioxide (CO2) and methane (CH4) emissions from reservoirs are currently being underestimated by up to 50%. This underestimation is due to inadequate characte...

  9. Investigating physical controls on methane and carbon dioxide fluxes over reservoirs using the eddy covariance method

    EPA Science Inventory

    Reservoirs are a globally important source of carbon to the atmosphere. Several recent studies have found that both carbon dioxide (CO2) and methane (CH4) emissions from reservoirs are currently being underestimated by up to 50%. This underestimation is due to inadequate characte...

  10. Carbon reservoirs in temperate South American Nothofagus forests.

    PubMed

    Böswald, Klaus; Lencinas, José D; Loguercio, Gabriel

    2002-01-08

    Humans are influencing the global carbon (C) cycle due to the combustion of fossil fuels and due to changes in land use management. These activities are fostering the manmade greenhouse effect and thus global climate change. Negative effects for life on earth are accounted for. Among others the international climate debate focused attention on forests and forestry, knowing about their considerable influence on global climate change. Whilst the global C budget is described fairly well, there is a lack of regional data describing the C reservoirs and flows in detail. This has to be constituted especially for forests in developing countries. This paper presents an investigation at regional scale of the C reservoirs in a South American forest ecosystem. The investigation puts emphasis on the area and stand volume estimation and the development of expansion and reduction factors. Vegetation types are classified and stratified, determining the corresponding areas and estimating the stand volume. Converting factors are developed to calculate C in branches and roots as a percentage of standing wood measured by inventories.

  11. The formation of the ocean’s anthropogenic carbon reservoir

    PubMed Central

    Iudicone, Daniele; Rodgers, Keith B.; Plancherel, Yves; Aumont, Olivier; Ito, Takamitsu; Key, Robert M.; Madec, Gurvan; Ishii, Masao

    2016-01-01

    The shallow overturning circulation of the oceans transports heat from the tropics to the mid-latitudes. This overturning also influences the uptake and storage of anthropogenic carbon (Cant). We demonstrate this by quantifying the relative importance of ocean thermodynamics, circulation and biogeochemistry in a global biochemistry and circulation model. Almost 2/3 of the Cant ocean uptake enters via gas exchange in waters that are lighter than the base of the ventilated thermocline. However, almost 2/3 of the excess Cant is stored below the thermocline. Our analysis shows that subtropical waters are a dominant component in the formation of subpolar waters and that these water masses essentially form a common Cant reservoir. This new method developed and presented here is intrinsically Lagrangian, as it by construction only considers the velocity or transport of waters across isopycnals. More generally, our approach provides an integral framework for linking ocean thermodynamics with biogeochemistry. PMID:27808101

  12. The formation of the ocean’s anthropogenic carbon reservoir

    NASA Astrophysics Data System (ADS)

    Iudicone, Daniele; Rodgers, Keith B.; Plancherel, Yves; Aumont, Olivier; Ito, Takamitsu; Key, Robert M.; Madec, Gurvan; Ishii, Masao

    2016-11-01

    The shallow overturning circulation of the oceans transports heat from the tropics to the mid-latitudes. This overturning also influences the uptake and storage of anthropogenic carbon (Cant). We demonstrate this by quantifying the relative importance of ocean thermodynamics, circulation and biogeochemistry in a global biochemistry and circulation model. Almost 2/3 of the Cant ocean uptake enters via gas exchange in waters that are lighter than the base of the ventilated thermocline. However, almost 2/3 of the excess Cant is stored below the thermocline. Our analysis shows that subtropical waters are a dominant component in the formation of subpolar waters and that these water masses essentially form a common Cant reservoir. This new method developed and presented here is intrinsically Lagrangian, as it by construction only considers the velocity or transport of waters across isopycnals. More generally, our approach provides an integral framework for linking ocean thermodynamics with biogeochemistry.

  13. Toward Reservoir-on-a-Chip: Fabricating Reservoir Micromodels by in Situ Growing Calcium Carbonate Nanocrystals in Microfluidic Channels.

    PubMed

    Wang, Wei; Chang, Sehoon; Gizzatov, Ayrat

    2017-08-30

    We introduce a novel and simple method to fabricate calcium carbonate (CaCO3) micromodels by in situ growing a thin layer of CaCO3 nanocrystals with a thickness of 1-2 μm in microfluidic channels. This approach enables us to fabricate synthetic CaCO3 reservoir micromodels having surfaces fully covered with calcite, while the dimensions and geometries of the micromodels are controllable on the basis of the original microfluidic channels. We have tuned the wettability of the CaCO3-coated microchannels at simulated oil reservoir conditions without introducing any chemical additives to the system; thus the resulting oil-wet surface makes the micromodel more faithfully resemble a natural carbonate reservoir rock. With the advantage of its excellent optical transparency, the micromodel allows us to directly visualize the complex multiphase flows and geochemical fluid-calcite interactions by spectroscopic and microscopic imaging techniques. The CaCO3-coated microfluidic channels provide new capabilities as a micromodel system to mimic real carbonate reservoir properties, which would allow us to perform a water-oil displacement experiment in small-volume samples for the rapid screening of candidate fluids for enhanced oil recovery (EOR). The immiscible fluid displacement process within carbonate micromodels has been demonstrated showing the water-oil-carbonate interactions at pore-scale in real time by fluorescence microscopic imaging.

  14. Field Demonstration of Horizontal Infill Drilling Using Cost-effective Integrated Reservoir Modeling--Mississippian Carbonates, Central Kansas

    SciTech Connect

    Saibal Bhattacharya

    2005-08-31

    Mississippian carbonate reservoirs have produced in excess of 1 billion barrels of oil in Kansas accounting for over 16% of the state's production. With declining production from other age reservoirs, the contribution of Mississippian reservoirs to Kansas's oil production has risen to 43% as of 2004. However, solution-enhanced features such as vertical shale intervals extending from the karst erosional surface at the top introduce complexities/compartmentalizations in Mississippian carbonate reservoirs. Coupled with this, strong water drives charge many of these reservoirs resulting in limited drainage from vertical wells due to high water cuts after an initial period of low water production. Moreover, most of these fields are operated by small independent operators without access to the knowledge bank of modern research in field characterization and exploitation/development practices. Thus, despite increasing importance of Mississippian fields to Kansas production, these fields are beset with low recovery factors and high abandonment rates leaving significant resources in the ground. Worldwide, horizontal infill wells have been successful in draining compartmentalized reservoirs with limited pressure depletion. The intent of this project was to demonstrate the application of horizontal wells to successfully exploit the remaining potential in mature Mississippian fields of the mid-continent. However, it is of critical importance that for horizontal wells to be economically successful, they must be selectively targeted. This project demonstrated the application of initial and secondary screening methods, based on publicly available data, to quickly shortlist fields in a target area for detailed studies to evaluate their potential to infill horizontal well applications. Advanced decline curve analyses were used to estimate missing well-level production data and to verify if the well produced under unchanging bottom-hole conditions--two commonly occurring data

  15. Microbial potential for carbon and nutrient cycling in a geogenic supercritical carbon dioxide reservoir.

    PubMed

    Freedman, Adam J E; Tan, BoonFei; Thompson, Janelle R

    2017-06-01

    Microorganisms catalyze carbon cycling and biogeochemical reactions in the deep subsurface and thus may be expected to influence the fate of injected supercritical (sc) CO2 following geological carbon sequestration (GCS). We hypothesized that natural subsurface scCO2 reservoirs, which serve as analogs for the long-term fate of sequestered scCO2 , harbor a 'deep carbonated biosphere' with carbon cycling potential. We sampled subsurface fluids from scCO2 -water separators at a natural scCO2 reservoir at McElmo Dome, Colorado for analysis of 16S rRNA gene diversity and metagenome content. Sequence annotations indicated dominance of Sulfurospirillum, Rhizobium, Desulfovibrio and four members of the Clostridiales family. Genomes extracted from metagenomes using homology and compositional approaches revealed diverse mechanisms for growth and nutrient cycling, including pathways for CO2 and N2 fixation, anaerobic respiration, sulfur oxidation, fermentation and potential for metabolic syntrophy. Differences in biogeochemical potential between two production well communities were consistent with differences in fluid chemical profiles, suggesting a potential link between microbial activity and geochemistry. The existence of a microbial ecosystem associated with the McElmo Dome scCO2 reservoir indicates that potential impacts of the deep biosphere on CO2 fate and transport should be taken into consideration as a component of GCS planning and modelling. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  16. Microbial potential for carbon and nutrient cycling in a geogenic supercritical carbon dioxide reservoir

    PubMed Central

    Freedman, Adam J.E.; Tan, BoonFei

    2017-01-01

    Summary Microorganisms catalyze carbon cycling and biogeochemical reactions in the deep subsurface and thus may be expected to influence the fate of injected supercritical (sc) CO2 following geological carbon sequestration (GCS). We hypothesized that natural subsurface scCO2 reservoirs, which serve as analogs for the long‐term fate of sequestered scCO2, harbor a ‘deep carbonated biosphere’ with carbon cycling potential. We sampled subsurface fluids from scCO2‐water separators at a natural scCO2 reservoir at McElmo Dome, Colorado for analysis of 16S rRNA gene diversity and metagenome content. Sequence annotations indicated dominance of Sulfurospirillum, Rhizobium, Desulfovibrio and four members of the Clostridiales family. Genomes extracted from metagenomes using homology and compositional approaches revealed diverse mechanisms for growth and nutrient cycling, including pathways for CO2 and N2 fixation, anaerobic respiration, sulfur oxidation, fermentation and potential for metabolic syntrophy. Differences in biogeochemical potential between two production well communities were consistent with differences in fluid chemical profiles, suggesting a potential link between microbial activity and geochemistry. The existence of a microbial ecosystem associated with the McElmo Dome scCO2 reservoir indicates that potential impacts of the deep biosphere on CO2 fate and transport should be taken into consideration as a component of GCS planning and modelling. PMID:28229521

  17. Carbon implications of Virgin Lands Campaign cropland expansion and post-Soviet agricultural land abandonment in Russia and Kazakhstan

    NASA Astrophysics Data System (ADS)

    Prishchepov, A. V.; Kurganova, I.; Schierhorn, F.; Lopes de Gerenyu, V.; Müller, D.; Kuzyakov, Y.

    2015-12-01

    Political economy and institutional changes regarding land use play crucial role in shaping land cover worldwide. Among such events was the Soviet Virgin Lands Campaign, when 45.2 million ha of virgin steppes were ploughed up from 1954 to 1963 in northern Eurasia. We took opportunity to evaluate carbon (C) costs of this Campaign, particularly with the account of massive cropland abandonment in the former Campaign area after demise of the Soviet Union in 1991. Within cropland mask produced with remotely sensed data, we spatially disaggregated historical annual sown area statistics at the provincial level for Russia and Kazakhstan based on cropland suitability assessment. We also adjusted our cropland allocation model with the use of 1:3,000,000 map depicting cropland expansion in Northern Kazakhstan. We used C bookkeeping approach to assess C dynamics based on soil stratification and C field measurements. The Campaign resulted in huge C losses from soils, which accounted for 611±47 Mt C in Russia and 241±11 Mt C in Kazakhstan for upper 0-50 cm soil layer during the first 20 years of cultivation. Such C losses could be compared with C losses due to plowing up the prairies in the mid-1930s in USA. Despite the huge C losses from soils during the Campaign, the total C budget in soils of both countries at national level was positive after 1991 due to sequestered C on abandoned lands, albeit the patterns of C loss during the Campaign and C sink in post-Soviet period differed. The C sink from 1991 to 2010 on abandoned croplands in Russia (45.5Mha) comprised 976±108Mt C and Kazakhstan (12.9Mha) comprised 240±34Mt C. However, already ongoing recultivation of abandoned cropland in Kazakhstan and already planned such activities in Russia, can release stored C on abandoned lands. Our study highlights the importance of environmental evaluation of such governmental programs and their alternatives, particularly, since such programs are not rare events in modern land

  18. CO2 Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. Annual report, January 1, 1995--December 31, 1995

    SciTech Connect

    Wehner, S.C.; Boomer, R.J.; Cole, R.; Preiditus, J.; Vogt, J.

    1996-09-01

    The application of cyclic CO{sub 2}, often referred to as the CO{sub 2} Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO{sub 2} H-n-P process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital intensive miscible projects. Texaco Exploration & Production Inc. and the U.S. Department of Energy have teamed up in an attempt to develop the CO{sub 2} Huff-n-Puff process in the Grayburg/San Andres formation; a light oil, shallow shelf carbonate reservoir within the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir. A significant amount of oil reserves are located in carbonate reservoirs. Specifically, the carbonates deposited in shallow shelf (SSC) environments make up the largest percentage of known reservoirs within the Permian Basin of North America. Many of these known resources have been under waterflooding operations for decades and are at risk of abandonment if crude oil recoveries cannot be economically enhanced. The selected site for this demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico.

  19. Numerical simulation of carbon dioxide effects in geothermal reservoirs

    SciTech Connect

    Moya, S.L.; Iglesias, E.R.

    1995-03-01

    We developed and coded a new equation of state (EOS) for water-carbon dioxide mixtures and coupled it to the TOUGH numerical simulator. This EOS is valid up to 350{degrees}C and 500 bar. Unlike previous thermodynamical models, it rigorously considers the non-ideal behavior of both components in the gaseous mixture and formally includes the effect of the compressibility of the liquid phase. We refer to the coupling of this EOS with TOUGH as TOUGH-DIOX. To complement this enhancement of TOUGH, we added indexed output files for easy selection and interpretation of results. We validated TOUGH-DIOX against published results. Furthermore we used TOUGH-DIOX to explore and compare mass and energy inflow performance relationships of geothermal wells with/without carbon dioxide (CO{sub 2}). Our results include the effects of a broad range of fluid and formation properties, initial conditions and history of reservoir production. This work contributes with generalized dimensionless inflow performance relationships appropriate for geothermal use.

  20. Distinguishing Carbonate Reservoir Pore Facies with Nuclear Magnetic Resonance Measurements

    SciTech Connect

    Genty, Coralie; Jensen, Jerry L. Ahr, Wayne M.

    2007-03-15

    Characterization of carbonate rocks may involve identifying the important pore types which are present. In the past, this task has required detailed petrographic analysis of many core samples. Here, we describe a method which uses nuclear magnetic resonance (NMR) measurements to reduce the amount of petrographic analysis needed for porosity typing of carbonate reservoir rocks.For a rock sample which has been measured with NMR, our method decomposes the log(T{sub 2}) spectrum into at most three Gaussian-shaped components and gives a set of nine parameters. Two characteristic quantities having geological significance are extracted from the nine parameters. Values of the two quantities are compared with a reference set, established from samples having both NMR and petrographic evaluations of porosity types. We use a Bayesian approach to the classification of the dominant porosity type.Tests of our method on 103 samples show a correct prediction in 60 to 90 percent of the samples. The lower success rate was obtained for samples with five porosity types from three fields; the higher success rate obtained with samples with three porosity types from one well. The use of geologically significant quantities extracted from the decomposition gives comparable success rate to those obtained using a standard, non-geological approach such as canonical variates.

  1. Soil organic carbon response to land abandonment along a pluviometric gradient in Mediterranean conditions (South of Spain).

    NASA Astrophysics Data System (ADS)

    Gabarron-Galeote, Miguel A.; Trigalet, Sylvain; van Wesemael, Bas

    2014-05-01

    Land abandonment has been the most important land use change in Mediterranean region over the last decades. After this conversion, a secondary succession process begins, during which soil organic carbon (SOC) is usually assumed to increase. However, the rate of accumulation strongly depends on climatic conditions and the extent to which precipitation and temperature determine SOC dynamics is largely unknown. The objective of this study is the estimation of SOC dynamic after land abandonment along a pluviometric gradient (1085-650-350 mm y-1). Plots abandoned in different periods (chronosequence) were selected on each site. SOC was determined using a spectrometer and dry combustion, vegetation cover was described, and NDVI, used as indicator of organic matter input to soils, was calculated from LANDSAT images. SOC increased following a logistic model in the two wettest sites, with decreasing accumulation rates as SOC stock approached a plateau. Accumulation rates were proportional to precipitation, being 0.16 for the wettest and 0.03 kg C m-2 y-1 for the intermediate site until reaching the long-term state, in 8 and 49 years respectively. In the driest site no SOC accumulation was measured. SOC and NDVI followed parallel trends along the gradient, so SOC stocks were mainly driven by inputs from vegetation. In addition, on the driest extreme of the gradient, another chronosequence was sampled at high altitude and low temperature. In this case, NDVI evolved following a logistic function but values were not high enough and organic matter input to soil did not trigger SOC accumulation.

  2. Implications of a reservoir model for the evolution of deep carbon

    NASA Astrophysics Data System (ADS)

    Kellogg, L. H.; Weisfeiler, M.; Turcotte, D. L.

    2016-12-01

    We consider a reservoir model for the evolution of carbon in Earth's deep interior. We begin with the assumption that the mantle reservoir that interacts with the surface is well mixed. We hypothesize that the loss of carbon from the mantle reservoir occurs primarily at mid-ocean ridges and we take the flux of carbon to be 36 ± 24 GtC yr-1 (Dasgupta and Hirschmann, 2010). We infer that the mass concentration of carbon is 5.3 ± 1.8 × 10-5. Assuming that the mass of the mantle reservoir is 4.043×1024 kg, the mass of carbon in that reservoir is 2.1±0.7×108 GtC. We further hypothesize that the addition of carbon to the mantle reservoir occurs primarily at subduction zones and take the flux of carbon to be 36 ± 12 GtC yr-1 (Dasgupta and Hirschmann, 2010). Thus within estimated uncertainties there is a steady state balance between the fluxes into and out of the mantle reservoir. A basic question is where this carbon came from. The present mass of carbon in the atmosphere of Venus is 1.28 × 108 GtC, which scales to be equivalent to 1.57 × 108 GtC in the Earth's atmosphere. This is much greater than the current mass of cabron in Earth's atmosphere but is close to the mass of carbon in the mantle reservoir given above. One explanation for the loss of carbon from Earth's atmosphere to its mantle has been given by Sleep and Zahnle (2001), who suggest that after the moon-forming giant impact at about 4.4 Ga, the carbon in the Earth's atmosphere was transferred into the mantle reservoir. We further suggest that the volcanic flux of carbon out of the mantle was responsible for the carbon concentrations in the surficial reservoirs today. In this scenario, carbon accumulated in the deep ocean until the carbon flux into the mantle due to subduction balanced the carbon flux out of the mantle due to volcanism.

  3. Developing the aquatic-coupled reservoir model to simulate carbon dioxide emission from a young boreal hydroelectric reservoir

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Roulet, N. T.; Strachan, I. B.; Tremblay, A.

    2013-12-01

    We developed a process-based biogeochemical reservoir model, called AF-DNDC (Aquatic-coupled Forest-DNDC), to project carbon (C) flux from water surface of a recently created hydro-electric reservoir that flooded a boreal landscape. The basis of the reservoir model is Forest-DNDC, a biogeochemical model for C and nitrogen cycling in forests and wetlands. AF-DNDC was developed by coupling a lake C model to a flooded version of Forest-DNDC. AF-DNDC includes the C cycling through the aquatic carbon pools, such as DIC (dissolved inorganic C), DOC (dissolved organic C), and planktonic community as well as C exchange between air, water, and sediment. AF-DNDC was used to examine the net change in carbon dioxide (CO2) exchange between the surface and the atmosphere over the first seven years post flooding of the Eastmain-1 reservoir in northern Quebec. With present day climate and environmental conditions, simulated daily CO2 emissions from the flooded forest averaged 1.69 g C m-2 d-1 (range 0 to 20.49), and from the flooded peatland averaged 0.87 g C m-2 d-1 (range 0 to 6.86). Simulated CO2 emissions decreased with the age of reservoir. They were larger than eddy-covariance measured CO2 fluxes from the water surface over flooded forests, but compared well to the eddy-covariance fluxes during the open-water period. The simulated emissions were significantly correlated with the measured fluxes from the flooded forest (r2 = 0.33; p < 0.01) and flooded peatland (r2 = 0.41; p < 0.01). The patterns over the year were similar. AF-DNDC is suitable for use to assess the major changes in CO2 exchange due to the creation of reservoirs in boreal regions.

  4. Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf Carbonate Reservoir, Class II

    SciTech Connect

    Hickman, T. Scott; Justice, James J.; Egg, Rebecca

    2001-08-07

    The Oxy operated Class 2 Project at West Welch Project is designed to demonstrate how the use of advanced technology can improve the economics of miscible CO2 injection projects in lower quality Shallow Shelf Carbonate reservoirs. The research and design phase (Budget Period 1) primarily involved advanced reservoir demonstration characterization. The current demonstration phase (Budget Period 2) is the implementation of the reservoir management plan for an optimum miscible CO2 flood design based on the reservoir characterization.

  5. Temperature-pressure conditions in coalbed methane reservoirs of the Black Warrior basin: Implications for carbon sequestration and enhanced coalbed methane recovery

    USGS Publications Warehouse

    Pashin, J.C.; McIntyre, M.R.

    2003-01-01

    equilibrate toward a normal hydrostatic pressure gradient after abandonment. Coal can hold large quantities of carbon dioxide under supercritical conditions, and supercritical isotherms indicate non-Langmiur conditions under which some carbon dioxide may remain mobile in coal or may react with formation fluids or minerals. Hence, carbon sequestration and enhanced coalbed methane recovery show great promise in subcritical reservoirs, and additional research is required to assess the behavior of carbon dioxide in coal under supercritical conditions where additional sequestration capacity may exist. ?? 2003 Elsevier Science B.V. All rights reserved.

  6. High spatial variability of carbon dioxide and methane emission in three tropical reservoirs

    NASA Astrophysics Data System (ADS)

    Reinaldo Paranaiba, José; Barros, Nathan O.; Mendonça, Raquel F.; Linkhorst, Annika; Isidorova, Anastasija; Roland, Fabio; Sobek, Sebastian

    2017-04-01

    In the tropics, many new large hydropower dams are being built, in order to produce renewable energy for economic growth. Most inland waters, such as rivers, lakes and reservoirs, emit greenhouse gases to the atmosphere, and especially tropical reservoirs have been pointed out as strong sources of methane. However, present estimates of greenhouse gas emission from reservoirs are limited by the amount of available data. In particular, the spatial variability of greenhouse gas emission from reservoirs is insufficiently understood. In order to test the hypothesis that the diffusive emission of carbon dioxide (CO2) and methane (CH4) from tropical reservoirs is characterized by strong spatial variability and incorrectly represented by measurements at one site only, we studied three reservoirs situated in different tropical climates, during the dry period. We conducted spatially resolved measurements of surface water concentrations of dissolved carbon dioxide and methane using an on-line equilibration system, as well as of the gas exchange velocity using floating chambers. We found pronounced spatial variability of diffusive CO2 and CH4 emission in all three reservoirs. River inflow areas were more likely to have high concentrations of particularly CH4, but also CO2, than other areas in the reservoirs. Close to the dam, CH4 concentrations were comparatively low in each reservoir. The variability of CH4 concentration was linked to geographical position, which we ascribe to hot spots of methanogenesis at sites of high sediment deposition, such as river inflow areas. The variability of CO2 concentration seemed instead rather to be linked to in-situ metabolism. Also the gas exchange velocity varied pronouncedly in each reservoir, but without any detectable systematic patterns, calling for further studies. We conclude that accurate upscaling of reservoir greenhouse gas emissions requires accounting for within-reservoir spatial variability, and that the anthropogenic increase

  7. Comparison of Carbon Dioxide Solubility Models in Brine for Use in Carbon Sequestration Reservoir Estimates

    NASA Astrophysics Data System (ADS)

    Karamalidis, A.; Wang, Z.; Small, M.; Dilmore, R. M.; Goodman, A. L.

    2011-12-01

    Carbon sequestration into deep geological formations, such as saline formations and oil and gas fields, is a promising method to mitigate global warming. Estimating carbon dioxide solubility (TPX) in brine under carbon sequestration conditions with high temperature, pressure and salinity is crucial in choosing suitable carbon sequestration reservoirs and determining the carbon dioxide storage capacity of each. Multiple mathematical models are available for predicting the solubility of CO2 in brine. Although comparisons of each model with a particular experimental data set collected under certain TPX conditions have been published by the model developers, few studies have been done to compare these models using a comprehensive experimental data set and rigorous statistical methods. In this study, available CO2 solubility experimental data and nine mathematical models for the prediction of CO2 solubility in brine were collected. Five of these predictive models are empirical or semi-empirical and the remainders are based on different equations of state. Statistical criteria, such as the AIC and BIC were employed to determine the goodness of fit of each mathematical model with the CO2 solubility experimental data set. Results of this analysis determine the best mathematical predictive model for the calculation of carbon dioxide solubility under carbon sequestration conditions. Preliminary analysis shows that simplified models with fewer variables perform equally well with those having more. The study also presents a quantitative approach to determine the best CO2 solubility predictive model through use of a regression tree.

  8. Flood-related, organic-carbon anomalies as possible temporal markers in reservoir bottom sediments

    USGS Publications Warehouse

    Juracek, K.E.

    2004-01-01

    Results of a study of sediment cores from four reservoirs in the upper Mississippi River Basin, USA, indicated that anomalous organic carbon concentrations associated with flood deposits may provide detectable temporal markers in reservoir bottom sediments. Temporal markers are needed for reservoir sediment studies to date sediment layers deposited between the 1963-64 cesium-137 peak and the present. For two of four reservoirs studied, anomalously low organic carbon concentrations were measured for a sample interval in the upper part of a sediment core. The anomalous interval was interpreted to have been deposited during the July 1993 flood that affected a large area of the upper Mississippi River Basin. Potentially, the July 1993 flood deposit may be used as a temporal marker in reservoir bottom sediments in parts of the basin affected by the flood. Several uncertainties remain regarding the viability of organic carbon as a temporal marker including the combination of flood, basin, and reservoir characteristics required to produce a recognizable organic carbon marker in the bottom sediment and the optimal sampling strategy needed to detect the marker in a sediment core. It is proposed that flood duration and basin size may be important factors as to whether or not an anomalous and detectable organic carbon layer is deposited in a reservoir. ?? Copyright by the North American Lake Management Society 2004.

  9. Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf Carbonate Reservoir

    SciTech Connect

    Rebecca Egg

    2002-09-30

    The OXY-operated Class 2 Project at West Welch is designed to demonstrate how the use of advanced technology can improve the economics of miscible CO{sub 2} injection projects in lower quality Shallow Shelf Carbonate reservoirs. The research and design phase (Budget Period 1) primarily involved advanced reservoir characterization. The current demonstration phase (Budget Period 2) is the implementation of the reservoir management plan for an optimum miscible CO{sub 2} flood design based on the reservoir characterization. Although Budget Period 1 for the Project officially ended 12/31/96, reservoir characterization and simulation work continued during the Budget Period 2. During the fifth and sixth annual reporting periods (8/3/98-8/2/00) covered by this report, work continued on interpretation of the cross well seismic data to create porosity and permeability profiles which were distributed into the reservoir geostatistically. The initial interwell seismic CO{sub 2} monitor survey was conducted, the acquired data processed and interpretation started. Only limited well work and facility construction was conducted in the project area. The CO{sub 2} injection initiated in October 1997 was continued, although the operator had to modify the operating plan in response to low injection rates, well performance and changes in CO{sub 2} supply. CO{sub 2} injection was focused in a smaller area to increase the reservoir processing rate. By the end of the reporting period three producers had shown sustained oil rate increases and ten wells had experienced gas (CO{sub 2}) breakthrough.

  10. Enhancement of Terrestrial Carbon Sinks through the Reclamation of Abandoned Mined Lands

    SciTech Connect

    Gary Kronrad

    2004-10-31

    This project will determine the optimal forest management method to employ for each of the major commercial tree species so that profitability of timber production only or the combination of timber production and carbon sequestration is maximized. The goal of this project is to achieve DOE's long-term cost goal of sequestering carbon at $10 or less per ton. Because the potential of a forest ecosystem to sequester carbon depends on the species, site quality and management regimes utilized, this project will determine how to optimize carbon sequestration by determining how to optimally manage each species, given a range of site qualities and economic variables. This project also will determine the effects of a carbon credit market on the method and profitability of forest management, the cost of sequestering carbon, and the amount of carbon that can be sequestered. Information from this project will be used to produce user-friendly manuals which will contain economic and biological data for each of the species. These manuals will inform landowners and forest managers how to manage forests for timber and/or carbon credits, how to maximize financial returns, how much money can be earned, and how much carbon can be stored. Manuals will be disseminated through state and federal agricultural extension services and the forest service of each state, and will be published in forest landowner magazines.

  11. Enhancement of Terrestrial Carbon Sinks throught the Reclamation of Abandoned Mined Lands

    SciTech Connect

    Gary Kronrad

    2006-06-30

    This project will determine the optimal forest management method to employ for each of the major commercial tree species so that profitability of timber production only or the combination of timber production and carbon sequestration is maximized. The goal of this project is to achieve DOE's long-term cost goal of sequestering carbon at $10 or less per ton. Because the potential of a forest ecosystem to sequester carbon depends on the species, site quality and management regimes utilized, this project will determine how to optimize carbon sequestration by determining how to optimally manage each species, given a range of site qualities and economic variables. This project also will determine the effects of a carbon credit market on the method and profitability of forest management, the cost of sequestering carbon, and the amount of carbon that can be sequestered. Information from this project will be used to produce user-friendly manuals which will contain economic and biological data for each of the species. These manuals will inform landowners and forest managers how to manage forests for timber and/or carbon credits, how to maximize financial returns, how much money can be earned, and how much carbon can be stored. Manuals will be disseminated through state and federal agricultural extension services and the forest service of each state, and will be published in forest landowner magazines.

  12. Enhancement of Terrestrial Carbon Sinks through the Reclamation of Abandoned Mined Lands

    SciTech Connect

    Gary Kronrad

    2005-04-30

    This project will determine the optimal forest management method to employ for each of the major commercial tree species so that profitability of timber production only or the combination of timber production and carbon sequestration is maximized. The goal of this project is to achieve DOE's long-term cost goal of sequestering carbon at $10 or less per ton. Because the potential of a forest ecosystem to sequester carbon depends on the species, site quality and management regimes utilized, this project will determine how to optimize carbon sequestration by determining how to optimally manage each species, given a range of site qualities and economic variables. This project also will determine the effects of a carbon credit market on the method and profitability of forest management, the cost of sequestering carbon, and the amount of carbon that can be sequestered. Information from this project will be used to produce user-friendly manuals which will contain economic and biological data for each of the species. These manuals will inform landowners and forest managers how to manage forests for timber and/or carbon credits, how to maximize financial returns, how much money can be earned, and how much carbon can be stored. Manuals will be disseminated through state and federal agricultural extension services and the forest service of each state, and will be published in forest landowner magazines.

  13. Enhancement of Terrestrial Carbon Sinks through the Reclamation of Abandoned Mined Lands

    SciTech Connect

    Gary Kronrad

    2006-01-31

    This project will determine the optimal forest management method to employ for each of the major commercial tree species so that profitability of timber production only or the combination of timber production and carbon sequestration is maximized. The goal of this project is to achieve DOE's long-term cost goal of sequestering carbon at $10 or less per ton. Because the potential of a forest ecosystem to sequester carbon depends on the species, site quality and management regimes utilized, this project will determine how to optimize carbon sequestration by determining how to optimally manage each species, given a range of site qualities and economic variables. This project also will determine the effects of a carbon credit market on the method and profitability of forest management, the cost of sequestering carbon, and the amount of carbon that can be sequestered. Information from this project will be used to produce user-friendly manuals which will contain economic and biological data for each of the species. These manuals will inform landowners and forest managers how to manage forests for timber and/or carbon credits, how to maximize financial returns, how much money can be earned, and how much carbon can be stored. Manuals will be disseminated through state and federal agricultural extension services and the forest service of each state, and will be published in forest landowner magazines.

  14. CO2 Huff-n-Puff Process in a Light Oil Shallow Shelf Carbonate Reservoir

    SciTech Connect

    Kovar, Mark; Wehner, Scott

    1998-01-13

    The application of cyclic CO2, often referred to as the CO2 Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO2 Huff-n-Puff process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital-intensive miscible projects. Texaco Exploration & Production Inc. and the U. S. Department of Energy have teamed up in an attempt to develop the CO2 Huff-n-Puff process in the Grayburg and San Andres formations which are light oil, shallow shelf carbonate reservoirs that exist throughout the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir. A significant amount of oil reserves are located in carbonate reservoirs. Specifically, the carbonates deposited in shallow shelf (SSC) environments make up the largest percentage of known reservoirs within the Permian Basin of North America. Many of these known resources have been under waterflooding operations for decades and are at risk of abandonment if crude oil recoveries cannot be economically enhanced. The selected sites for this demonstration project are the Central Vacuum Unit waterflood in Lea County, New Mexico and the Sundown Slaughter Field in Hockley County, Texas. Miscible CO2 flooding is the process of choice for enhancing recovery of light oils and already accounts for over 12% of the Permian Basin's daily production. There are significant probable reserves associated with future miscible CO2 projects. However, many are marginally economic at current market conditions due to large up-front capital commitments for a peak response, which may be several years in the future. The resulting negative cash-flow is sometimes too much for an operator to absorb. The CO2 Huff-n-Puff process is being investigated as a near

  15. Carbon Dioxide Emissions from Reservoirs in the Lower Jordan Watershed

    PubMed Central

    Alshboul, Zeyad; Lorke, Andreas

    2015-01-01

    We have analyzed monthly hydrological, meteorological and water quality data from three irrigation and drinking water reservoirs in the lower Jordan River basin and estimated the atmospheric emission rates of CO2. The data were collected between 2006 and 2013 and show that the reservoirs, which differ in size and age, were net sources of CO2. The estimated surface fluxes were comparable in magnitude to those reported for hydroelectric reservoirs in the tropical and sub-tropical zones. Highest emission rates were observed for a newly established reservoir, which was initially filled during the sampling period. In the two older reservoirs, CO2 partial pressures and fluxes were significantly decreasing during the observation period, which could be related to simultaneously occurring temporal trends in water residence time and chemical composition of the water. The results indicate a strong influence of water and reservoir management (e.g. water consumption) on CO2 emission rates, which is affected by the increasing anthropogenic pressure on the limited water resources in the study area. The low wind speed and relatively high pH favored chemical enhancement of the CO2 gas exchange at the reservoir surfaces, which caused on average a four-fold enhancement of the fluxes. A sensitivity analysis indicates that the uncertainty of the estimated fluxes is, besides pH, mainly affected by the poorly resolved wind speed and resulting uncertainty of the chemical enhancement factor. PMID:26588241

  16. Carbon Dioxide Emissions from Reservoirs in the Lower Jordan Watershed.

    PubMed

    Alshboul, Zeyad; Lorke, Andreas

    2015-01-01

    We have analyzed monthly hydrological, meteorological and water quality data from three irrigation and drinking water reservoirs in the lower Jordan River basin and estimated the atmospheric emission rates of CO2. The data were collected between 2006 and 2013 and show that the reservoirs, which differ in size and age, were net sources of CO2. The estimated surface fluxes were comparable in magnitude to those reported for hydroelectric reservoirs in the tropical and sub-tropical zones. Highest emission rates were observed for a newly established reservoir, which was initially filled during the sampling period. In the two older reservoirs, CO2 partial pressures and fluxes were significantly decreasing during the observation period, which could be related to simultaneously occurring temporal trends in water residence time and chemical composition of the water. The results indicate a strong influence of water and reservoir management (e.g. water consumption) on CO2 emission rates, which is affected by the increasing anthropogenic pressure on the limited water resources in the study area. The low wind speed and relatively high pH favored chemical enhancement of the CO2 gas exchange at the reservoir surfaces, which caused on average a four-fold enhancement of the fluxes. A sensitivity analysis indicates that the uncertainty of the estimated fluxes is, besides pH, mainly affected by the poorly resolved wind speed and resulting uncertainty of the chemical enhancement factor.

  17. Calibration of NMR well logs from carbonate reservoirs with laboratory NMR measurements and μXRCT

    SciTech Connect

    Mason, Harris E.; Smith, Megan M.; Hao, Yue; Carroll, Susan A.

    2014-12-31

    The use of nuclear magnetic resonance (NMR) well log data has the potential to provide in-situ porosity, pore size distributions, and permeability of target carbonate CO₂ storage reservoirs. However, these methods which have been successfully applied to sandstones have yet to be completely validated for carbonate reservoirs. Here, we have taken an approach to validate NMR measurements of carbonate rock cores with independent measurements of permeability and pore surface area to volume (S/V) distributions using differential pressure measurements and micro X-ray computed tomography (μXRCT) imaging methods, respectively. We observe that using standard methods for determining permeability from NMR data incorrectly predicts these values by orders of magnitude. However, we do observe promise that NMR measurements provide reasonable estimates of pore S/V distributions, and with further independent measurements of the carbonate rock properties that universally applicable relationships between NMR measured properties may be developed for in-situ well logging applications of carbonate reservoirs.

  18. Carbon dioxide storage in unconventional reservoirs workshop: summary of recommendations

    USGS Publications Warehouse

    Jones, Kevin B.; Blondes, Madalyn S.

    2015-01-01

    The storage capacity for all unconventional reservoirs may be modeled using a volumetric equation starting with the extent of the rock unit and adjusted using these key factors and reaction terms. The ideas that were developed during this workshop can be used by USGS scientists to develop a methodology to assess the CO2 storage resource in unconventional reservoirs. This methodology could then be released for public comment and peer review. After completing this development process, the USGS could then use the methodology to assess the CO2 storage resource in unconventional reservoirs.

  19. Modelling Orthorhombic Anisotropic Effects for Reservoir Fracture Characterization of a Naturally Fractured Tight Carbonate Reservoir, Onshore Texas, USA

    NASA Astrophysics Data System (ADS)

    Osinowo, Olawale Olakunle; Chapman, Mark; Bell, Rebecca; Lynn, Heloise B.

    2017-09-01

    In this study we present a step-by-step theoretical modelling approach, using established seismic wave propagation theories in anisotropic media, to generate unique anisotropic reflection patterns observed from three-dimensional pure-mode pressure (3D-PP), full-azimuth and full-offset seismic reflection data acquired over a naturally fractured tight carbonate field, onshore Texas, USA. Our aim is to gain an insight into the internal structures of the carbonate reservoir responsible for the observed anisotropic reflection patterns. From the generated model we were able to establish that the observed field seismic reflection patterns indicate azimuthal anisotropy in the form of crack induced shear-wave splitting and variation in P-wave velocity with offset and azimuth. Amplitude variation with azimuth (AVAZ) analysis also confirmed multi-crack sets induced anisotropy which is characteristic of orthorhombic symmetry, evident as multiple bright and dim-amplitude azimuth directions as well as complete reversal of bright-amplitude to dim-amplitude azimuth direction as the angle of incidence increases from near (≤15°) to mid (≥30°) offsets. Finally, we fitted the generated P-wave velocity into an ellipse to determine the intensity and orientation (N26E) of the open crack set as well as the direction of the minimum in situ stress axis (N116E) within the reservoir. The derived information served as an aid for the design of horizontal well paths that would intercept open fractures and ensure production optimization of the carbonate reservoir, which was on production decline despite reservoir studies that indicate un-depleted reserves.

  20. How 3-D, 3-C seismic characterized a carbonate reservoir

    SciTech Connect

    Arestad, J.F.; Mattocks, B.W.; Davis, T.L.; Benson, R.D.

    1995-04-01

    The Reservoir Characterization Project (RCP) at the Colorado School of Mines has pioneered research into 3-D, 3-C (multicomponent) reflection seismology for nearly a decade utilizing both P-wave and S-wave sources. Multicomponent-seismic surveys provide significantly more information about petroleum reservoirs than compressional-wave surveys. Initial 3-D, 3-C surveys acquired by RCP were targeted at characterizing naturally fractured reservoirs. The current phase of the project is oriented towards utilizing shear waves to discriminate lithologic and diagenetic changes within stratigraphic reservoirs where compressional-seismic data has not be effective. The Joffre field, Nisku reservoir, is the site of RCP`s ongoing multidisciplinary research effort in Western Canada. The research team is directed by Colorado School of Mines faculty with graduate team members from geology, geophysics and petroleum engineering departments. While this study is still in progress, some key findings and directions of this research are reported here. The following topics will be discussed: Joffre field 3-D, 3-C survey; compressional wave 3-D technique; shear-wave 3-D technique; converted-wave 3-D technique; reservoir characterization, and future directions.

  1. Reservoir zonation in Silurian-Devonian carbonates of Wells field, Dawson County, Texas

    SciTech Connect

    Mazzullo, L.J. )

    1992-04-01

    Wells field in Dawson County, Texas, has produced over 7.5 million bbl since 1955 from Silurian-Devonian carbonates. Although originally classified as a Devonian field, production there actually is out of the Silurian Wristen and Fusselman formations. Wells field is an extremely complex system of structured and stratigraphic reservoirs not easily characterized by traditional subsurface mapping techniques. Detailed lithologic analyses of well cuttings from 29 wells in and around this field were done to evaluate reservoir zonation and potentials for either new field development wells, or recompletions from existing well bores. These analyses have shown that paleotopographic highs on the Fusselman unconformity across the field created optimum sites for Fusselman dolomite reservoir development, and collateral development of Wristen reservoirs. The Wristen reservoirs are in the form of porous carbonate mounds that grew adjacent to the paleotopographically high areas, or simple compactionally fractured cherty carbonates over these highs. The recognition of Fusselman paleotopography in most wells is implied by thickness and facies changes in the overlying Wristen section. A certain amount of structure and facies-induced reservoir separation has been documented. The results of this study have been used to identify several areas of the field where each of the three reservoirs could be exploited for underdeveloped reserves.

  2. The role of sequence stratigraphy in 3-D characterization of carbonate reservoirs

    SciTech Connect

    Tinker, S.W.; Brondos, M.D.; Brinton, L. )

    1996-01-01

    The product of 3-D reservoir characterization is a 3-D reservoir model. The integrity of the 3-D reservoir model is largely a function of the stratigraphic framework. Interpreting the correct stratigraphic framework for a subsurface reservoir is the most difficult and creative part of the 3-D modeling process. Sequence- and seismic-stratigraphic interpretation provide the best stratigraphic framework for 3-D reservoir modeling. Depositional sequences are comprised of many petrophysically-distinct lithofacies regions. If each lithofacies region was uniform and homogeneous, it would be reasonable to use a lithofacies ([open quote]layer-cake[close quote]) framework interpretation to distribute data in a 3-D model. However, lithofacies are typically time- transgressive, and often internally heterogeneous because geologic processes such as siliciclastic sediment deposition, sediment bypass, hardground formation, variable diagenesis, and facies shifts occur along depositional time surfaces on carbonate platforms. Therefore, a sequence stratigraphic framework interpretation, in which stratal geometries are honored, is better for controlling the distribution of petrophysical data in 3-D. The role that sequence stratigraphy plays in the 3-D characterization of carbonate reservoirs will be presented using two outcrop and four subsurface studies from the Paleozoic. The outcrop examples illustrate the important distinction between lithostratigraphic and sequence stratigraphic correlation, and the subsurface examples illustrate the process of quantification, integration, reduction, and analysis of geological, petrophysical, seismic, and engineering data. The concepts and techniques can be applied to carbonate reservoirs of any age.

  3. IMPACT OF FOREST HARVESTING ON RESERVOIRS AND LAKES: CARBON DYNAMICS AND MICROBIAL CYCLING

    NASA Astrophysics Data System (ADS)

    Ouellet, A.; Tremblay, L.; Lucotte, M. M.; Gelinas, Y.

    2009-12-01

    Boreal lakes and reservoirs are net heterotrophic systems. Differences in dissolved CO2 concentrations between man-made reservoirs and natural lakes suggest higher CO2 fluxes to the atmosphere from reservoirs than from lakes; human-induced perturbations such as deforestation also induce changes to the carbon cycle in aquatic systems. We used bulk analytical techniques to better characterize the impact of reservoir formation and deforestation on the processes controlling the cycling of organic carbon in boreal aquatic systems. The water column of natural and deforested lakes and reservoirs was analyzed for dissolved and particulate organic matter (DOM and POM, respectively), dissolved inorganic carbon (DIC), oxygen saturation and CO2. Atomic C:N ratios, δ13Corg, δ15Ntot and amino acids biomarkers analyses were also carried out on DOM and POM. Differences in carbon concentration, atomic C/N ratios and δ13Corg reflect the impact of deforestation on the quality and quantity of OM found in lakes and reservoirs. Water-column profiles of δ13C-DIC and δ13C-POM show large variability with perturbation indicating that there are differences in the biogeochemical processes that control carbon cycling in the different environments. These findings along with amino acids analyses show that inputs of terrestrial dissolved organic nitrogen and carbon better stimulates bacterial growth than algal activities, which results in increased aqueous CO2 concentrations and fluxes to the atmosphere. A statistical analysis of the biomarkers suggests contrasting DOM/POM sources and degradation pathways with wood harvesting and reservoir operation. Human-induced land use and hydrological modifications drive the carbon cycle of fresh water systems, which in turn modulates green house gas emissions to the atmosphere.

  4. Imaging and characterization of a carbonate hydrocarbon reservoir analogue using GPR attributes

    NASA Astrophysics Data System (ADS)

    Forte, E.; Pipan, M.; Casabianca, D.; Di Cuia, R.; Riva, A.

    2012-06-01

    We adapt and test seismic attributes techniques on a 2-D and 3-D multi-frequency GPR dataset recorded in an abandoned limestone quarry, analogous to a specific set of hydrocarbon reservoirs. Our main objective was to image the vertical and lateral lithological variations, the network of stratigraphic joints and fractures and to characterize the rock mass based on the radar response. We apply semi-automatic horizon mapping techniques using manually picked seeds (control points) on selected attributes, and automatic extrapolation both on in-line and cross-line, starting from seed positions. We also apply Principal Component Analysis (PCA) and cluster analysis on group data with similar multi-attribute response to reduce the total number of calculated attributes by minimizing the interpreter's bias. We compare and validate the results with direct outcrop measures, imaging a hydrocarbon reservoir analogue in 3-D to over 10 m beneath the topographic surface.

  5. IMPROVED OIL RECOVERY IN MISSISSIPPIAN CARBONATE RESERVOIRS OF KANSAS - NEAR TERM - CLASS 2

    SciTech Connect

    Timothy R. Carr; Don W. Green; G. Paul Willhite

    2000-04-30

    This annual report describes progress during the final year of the project entitled ''Improved Oil Recovery in Mississippian Carbonate Reservoirs in Kansas''. This project funded under the Department of Energy's Class 2 program targets improving the reservoir performance of mature oil fields located in shallow shelf carbonate reservoirs. The focus of the project was development and demonstration of cost-effective reservoir description and management technologies to extend the economic life of mature reservoirs in Kansas and the mid-continent. As part of the project, tools and techniques for reservoir description and management were developed, modified and demonstrated, including PfEFFER spreadsheet log analysis software. The world-wide-web was used to provide rapid and flexible dissemination of the project results through the Internet. A summary of demonstration phase at the Schaben and Ness City North sites demonstrates the effectiveness of the proposed reservoir management strategies and technologies. At the Schaben Field, a total of 22 additional locations were evaluated based on the reservoir characterization and simulation studies and resulted in a significant incremental production increase. At Ness City North Field, a horizontal infill well (Mull Ummel No.4H) was planned and drilled based on the results of reservoir characterization and simulation studies to optimize the location and length. The well produced excellent and predicted oil rates for the first two months. Unexpected presence of vertical shale intervals in the lateral resulted in loss of the hole. While the horizontal well was not economically successful, the technology was demonstrated to have potential to recover significant additional reserves in Kansas and the Midcontinent. Several low-cost approaches were developed to evaluate candidate reservoirs for potential horizontal well applications at the field scale, lease level, and well level, and enable the small independent producer to identify

  6. Jurassic carbonate reservoirs of the Amu Darya Basin, Uzbekistan and Turkmenistan

    SciTech Connect

    Shein, V.S.; Fortunatova, N.K.; Neilson, J.E.

    1995-08-01

    The Amu Darya Basin is a world class hydrocarbon province. Current reserves estimates are 220 TCF of gas and 800 MMbbl of oil and condensate, 50% of which is reservoired in Late Jurassic carbonates. Exploration opportunities still exist in large parts of the basin which are relatively undrilled. Within the 100-600m thick carbonate sequence, reservoir facies include reefs, shelf grainstones and turbidite fares. The major seal are Kimmeridgian - Tithonian evaporates which are up to 1600m thick in the basin centre. Stratigraphic trapping is common and often enhanced by structural modifications. The reservoirs are in communication with a major gas-prone Early-Middle Jurassic source rock. Oil-prone source rocks are thought to occur in basinal sediments which are coeval with the Late Jurassic reservoirs. Carbonate sedimentation commenced during the Late Jurassic with the development of a ramp complex. This evolved into a rimmed shelf with barrier and pinnacle reefs. Several cycles of relative sea-level change (largely eustatic?) influence the carbonate ramp/shelf systems and effect the distribution of reservoir facies. Numerous empirical observations by VNIGNI scientists on carbonate successions have enabled them to develop mathematically calculated indices for facies and reservoir prediction, which have been applied successfully in the Amu Darya Basin. Reservoir quality in the limestones is strongly controlled by primary facies. Reefs and shelf grainstones display the best reservoir characteristics. Whilst many facies have good total porosity, it is only the reef and grainstone belts where connected porosity (with pore throats greater than 10um) becomes effective. Burial cements are rare. Freshwater solution and cementation has often improved or preserved primary porosity.

  7. FOREST ECOSYSTEM CARBON AND NITROGEN ACCUMULATION DURING THE FIRST CENTURY AFTER AGRICULTURAL ABANDONMENT

    EPA Science Inventory

    Forests of the northeastern U.S. are expected to serve as a substantial sink for carbon (C) and nitrogen (N) as they recover from extensive clearing and agriculture. However, questions remain concerning the rate, distribution and duration of this potential sink. We used a chron...

  8. FOREST ECOSYSTEM CARBON AND NITROGEN ACCUMULATION DURING THE FIRST CENTURY AFTER AGRICULTURAL ABANDONMENT

    EPA Science Inventory

    Forests of the northeastern U.S. are expected to serve as a substantial sink for carbon (C) and nitrogen (N) as they recover from extensive clearing and agriculture. However, questions remain concerning the rate, distribution and duration of this potential sink. We used a chron...

  9. The lower Miocene Liuhua carbonate reservoir, Pearl River Mouth basin, offshore People's Republic of China

    SciTech Connect

    Turner, N.L. )

    1990-06-01

    Since the drilling in January 1987 of the Amoco Liuhua 11-1-1A discovery well located 220 km southeast of Hong Kong, five additional wells have drilled and tested this lower Miocene Zhujiang Formation carbonate reservoir. Deposition of upper Zhujiang carbonates in the Liuhua area took place in an isolated platform environment. Major facies are (1) a platform-rim reef composed of red algae and coral boundstones, (2) a back-reef lagoon of fine-grained carbonates, (3) a large interior platform bank dominated by red algae but with a red algal-coral fringe on the south and southwest sides, (4) platform grainrocks, and (5) platform to lagoonal mud-supported carbonates. A paleo-water table surface present in every well represents a time of regional exposure. The reservoir is subdivided into five diagenetic carbonate units that are correlated across the platform and that cross facies boundaries and inferred time lines. The uppermost unit is a thin, tightly cemented carbonate formed at the time of drowning of the platform. Two thick highly leached carbonate units with porosities and permeabilities as high as 30% and several darcys comprise most of the reservoir. They are separated by a thin (7 m) tighter interval that formed by cementation below the water table of an exposure surface. The less porous unit at the base of the reservoir formed as a result of interaction between oil and water causing calcite cementation. Leaching continued in the carbonate below the reservoir and biodegradation occurred after oil had filled the structure. Further drilling and testing will determine the limits of the diagenetic units and whether the reservoir has commercial potential.

  10. Modeling dolomitized carbonate-ramp reservoirs: A case study of the Seminole San Andres unit. Part 2 -- Seismic modeling, reservoir geostatistics, and reservoir simulation

    SciTech Connect

    Wang, F.P.; Dai, J.; Kerans, C.

    1998-11-01

    In part 1 of this paper, the authors discussed the rock-fabric/petrophysical classes for dolomitized carbonate-ramp rocks, the effects of rock fabric and pore type on petrophysical properties, petrophysical models for analyzing wireline logs, the critical scales for defining geologic framework, and 3-D geologic modeling. Part 2 focuses on geophysical and engineering characterizations, including seismic modeling, reservoir geostatistics, stochastic modeling, and reservoir simulation. Synthetic seismograms of 30 to 200 Hz were generated to study the level of seismic resolution required to capture the high-frequency geologic features in dolomitized carbonate-ramp reservoirs. Outcrop data were collected to investigate effects of sampling interval and scale-up of block size on geostatistical parameters. Semivariogram analysis of outcrop data showed that the sill of log permeability decreases and the correlation length increases with an increase of horizontal block size. Permeability models were generated using conventional linear interpolation, stochastic realizations without stratigraphic constraints, and stochastic realizations with stratigraphic constraints. Simulations of a fine-scale Lawyer Canyon outcrop model were used to study the factors affecting waterflooding performance. Simulation results show that waterflooding performance depends strongly on the geometry and stacking pattern of the rock-fabric units and on the location of production and injection wells.

  11. Major influencing factors of water flooding in abnormally high-pressure carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Qingying, Hou; Kaiyuan, Chen; Zifei, Fan; Libing, Fu; Yefei, Chen

    2017-01-01

    The higher pressure coefficient is the major characteristics of the abnormal high pressure carbonate reservoirs, which the pressure coefficient generally exceeds 1.2 and the initial formation pressure is higher than normal sandstone reservoirs. Due to the large pressure difference between initial formation and saturated pressure, oil wells are capable to production with high flow rate by the natural energy at early production stage. When the formation pressure drops to the saturation pressure, the water or gas is usually injected to stabilize the well productivity and sustain the formation pressure. Based on the characteristics of Kenkiak oilfield, a typical abnormal high pressure carbonate reservoir, a well group model is designed to simulate and analyze the influence factors on water flooding. The conclusion is that permeability, interlayer difference and reserve abundance are the main three factors on the water flooding development in these reservoirs.

  12. Calculation of hydrocarbon-in-place in gas and gas-condensate reservoirs - Carbon dioxide sequestration

    USGS Publications Warehouse

    Verma, Mahendra K.

    2012-01-01

    The Energy Independence and Security Act of 2007 (Public Law 110-140) authorized the U.S. Geological Survey (USGS) to conduct a national assessment of geologic storage resources for carbon dioxide (CO2), requiring estimation of hydrocarbon-in-place volumes and formation volume factors for all the oil, gas, and gas-condensate reservoirs within the U.S. sedimentary basins. The procedures to calculate in-place volumes for oil and gas reservoirs have already been presented by Verma and Bird (2005) to help with the USGS assessment of the undiscovered resources in the National Petroleum Reserve, Alaska, but there is no straightforward procedure available for calculating in-place volumes for gas-condensate reservoirs for the carbon sequestration project. The objective of the present study is to propose a simple procedure for calculating the hydrocarbon-in-place volume of a condensate reservoir to help estimate the hydrocarbon pore volume for potential CO2 sequestration.

  13. Seasonal Changes in Plankton Food Web Structure and Carbon Dioxide Flux from Southern California Reservoirs

    PubMed Central

    Adamczyk, Emily M.; Shurin, Jonathan B.

    2015-01-01

    Reservoirs around the world contribute to cycling of carbon dioxide (CO2) with the atmosphere, but there is little information on how ecosystem processes determine the absorption or emission of CO2. Reservoirs are the most prevalent freshwater systems in the arid southwest of North America, yet it is unclear whether they sequester or release CO2 and therefore how water impoundment impacts global carbon cycling. We sampled three reservoirs in San Diego, California, weekly for one year. We measured seasonal variation in the abundances of bacteria, phytoplankton, and zooplankton, as well as water chemistry (pH, nutrients, ions, dissolved organic carbon [DOC]), which were used to estimate partial pressure of CO2 (pCO2), and CO2 flux. We found that San Diego reservoirs are most often undersaturated with CO2 with respect to the atmosphere and are estimated to absorb on average 3.22 mmol C m-2 day-1. pCO2 was highest in the winter and lower in the summer, indicating seasonal shifts in the magnitudes of photosynthesis and respiration associated with day length, temperature and water inputs. Abundances of microbes (bacteria) peaked in the winter along with pCO2, while phytoplankton, nutrients, zooplankton and DOC were all unrelated to pCO2. Our data indicate that reservoirs of semi-arid environments may primarily function as carbon sinks, and that carbon flux varies seasonally but is unrelated to nutrient or DOC availability, or the abundances of phytoplankton or zooplankton. PMID:26473601

  14. Seasonal Changes in Plankton Food Web Structure and Carbon Dioxide Flux from Southern California Reservoirs.

    PubMed

    Adamczyk, Emily M; Shurin, Jonathan B

    2015-01-01

    Reservoirs around the world contribute to cycling of carbon dioxide (CO2) with the atmosphere, but there is little information on how ecosystem processes determine the absorption or emission of CO2. Reservoirs are the most prevalent freshwater systems in the arid southwest of North America, yet it is unclear whether they sequester or release CO2 and therefore how water impoundment impacts global carbon cycling. We sampled three reservoirs in San Diego, California, weekly for one year. We measured seasonal variation in the abundances of bacteria, phytoplankton, and zooplankton, as well as water chemistry (pH, nutrients, ions, dissolved organic carbon [DOC]), which were used to estimate partial pressure of CO2 (pCO2), and CO2 flux. We found that San Diego reservoirs are most often undersaturated with CO2 with respect to the atmosphere and are estimated to absorb on average 3.22 mmol C m(-2) day(-1). pCO2 was highest in the winter and lower in the summer, indicating seasonal shifts in the magnitudes of photosynthesis and respiration associated with day length, temperature and water inputs. Abundances of microbes (bacteria) peaked in the winter along with pCO2, while phytoplankton, nutrients, zooplankton and DOC were all unrelated to pCO2. Our data indicate that reservoirs of semi-arid environments may primarily function as carbon sinks, and that carbon flux varies seasonally but is unrelated to nutrient or DOC availability, or the abundances of phytoplankton or zooplankton.

  15. Forest gardening on abandoned terraces links local biomass carbon accumulation to international carbon markets, reverses land degradation, improves food diversity, and increases farmer income

    NASA Astrophysics Data System (ADS)

    Schmidt, Hans-Peter; Pandit, Bishnu Hari; Kammann, Claudia

    2017-04-01

    Despite chronic underproduction of food in Nepal, more and more agricultural land is abandoned especially in the remote middle hills and mountains. Male and young workers leave the villages for higher wages in the bigger cities or abroad. By now, most villages are mainly populated by women, children and elderly persons maintaining the gardens and fields close to the houses and leave the centenarian terraces fallow. Erosion, vanishing water resources, losses of soil organic carbon and the weakening of the local agro-economy become increasingly problematic. During the rainy season of 2015/16, 86 farmer families from four villages replanted their abandoned terraces with 25,000 mixed trees, mostly Cinnamon, Moringa, Mulberry, Lemon, Michelia, Paulownia, and various nuts. All trees were planted with a blend of organic biochar-based fertilizer and compost, since it was convincingly demonstrated by more than 20 field trials in this region that this was the most plant-growth promoting method. Mulching of the trees with rice straw or thatch grass was generalized. To let the young tries pass the critical seven months of dry season, water retention ponds with pipe irrigation were installed. Farmers were organized in groups of three families to mutually help and control the tree maintenance which led to an average tree survival rate of more than 80% after the first year compared to less than 50% in many country-wide forestation projects since the 1980s. Between the lower and upper lines of trees on the terraces, ginger, turmeric, black beans, onions, lentils and other secondary crops were cultivated using the same organic biochar based fertilizer and mulching techniques. What may seem a reasonable approach for many places, is in many of the poorest countries simply not possible to realize because village families do often not have the necessary initial investment for saplings and irrigation facilities at their disposal. Therefore, the Ithaka Institute linked the forest garden

  16. Karst-controlled reservoir heterogeneity in Ellenburger group carbonates of west Texas

    SciTech Connect

    Kerans, C.

    1988-10-01

    Petroleum production from restricted shelf carbonates of the Lower Ordovician Ellenburger group is commonly considered to have been a result of a pervasive, relatively homogeneous tectonic fracture system within the reservoir rock. However, regional facies and diagenetic (paleokarst) studies of Ellenburger strata, based on cores and wireline logs, have demonstrated that significant reservoir compartmentalization was caused by karst modification in the upper part of the unit. 19 figures.

  17. Probe imaging studies of magnetic susceptibility and permeability for sensitive characterisation of carbonate reservoir rocks

    NASA Astrophysics Data System (ADS)

    Ivakhnenko, Aleksandr; Bigaliyeva, Akmaral; Dubinin, Vladislav

    2016-04-01

    In this study were disclosed the main principals of identifying petrophysical properties of carbonate reservoirs such as porosity, permeability and magnetic susceptibility. While exploring and developing reservoir there are significant diversity of tasks that can be solved by appropriate knowledge of properties which are listed above. Behavior of fluid flow, distribution of hydrocarbons and other various industrial applications can be solved by measuring areal distribution of these petrophysical parameters. The results demonstrate how magnetic probe and hysteresis measurements correlate with petrophysical parameters in carbonate reservoirs. We made experimental measurements and theoretical calculations of how much magnetic susceptibility depends on the porosity of the rocks and analyzed data with graphics. In theoretical model of the carbonate rocks we considered calcite, dolomite, quartz and combinations of calcite and dolomite, calcite and Fe-dolomite, calcite and quartz, calcite and aragonite with increasing concentrations of the dolomite, Fe-dolomite, quartz and aragonite up to 50% with step of 5%. Here we defined dependence of magnetic susceptibility from the porosity: the higher porosity measurements, the less slope of magnetic susceptibility, consequently mass magnetization is higher for diamagnetic and lower for paramagnetic carbonate rocks, but in the both cases magnetic susceptibility tries to reach zero with increasing of the total porosity. Rock measurements demonstrate that reservoir zones of the low diamagnetic magnetic susceptibility are generally correlated with higher permeability and also porosity distribution. However for different carbonate reservoirs we establish different relationships depending on the complexity of their mineralogy and texture. Application of integral understanding in distribution of permeability, porosity and mineral content in heterogeneous carbonates represented by this approach can be useful tool for carbonate reservoir

  18. IMPROVED OIL RECOVERY IN MISSISSIPPIAN CARBONATE RESERVOIRS OF KANSAS--NEAR TERM--CLASS 2

    SciTech Connect

    Timothy R. Carr; Don W. Green; G. Paul Willhite

    1999-06-01

    This annual report describes progress during the third year of the project entitled ''Improved Oil Recovery in Mississippian Carbonate Reservoirs in Kansas''. This project funded under the Department of Energy's Class 2 program targets improving the reservoir performance of mature oil fields located in shallow shelf carbonate reservoirs. The focus of this project is development and demonstration of cost-effective reservoir description and management technologies to extend the economic life of mature reservoirs in Kansas and the mid-continent. The project introduced a number of potentially useful technologies, and demonstrated these technologies in actual oil field operations. Advanced technology was tailored specifically to the scale appropriate to the operations of Kansas producers. An extensive technology transfer effort is ongoing. Traditional technology transfer methods (e.g., publications and workshops) are supplemented with a public domain relational database and an online package of project results that is available through the Internet. The goal is to provide the independent complete access to project data, project results and project technology on their desktop. Included in this report is a summary of significant project results at the demonstration site (Schaben Field, Ness County, Kansas). The value of cost-effective techniques for reservoir characterization and simulation at Schaben Field were demonstrated to independent operators. All major operators at Schaben have used results of the reservoir management strategy to locate and drill additional infill locations. At the Schaben Demonstration Site, the additional locations resulted in incremental production increases of 200 BOPD from a smaller number of wells.

  19. Improved Oil Recovery in Mississippian Carbonate Reservoirs of Kansas -- Near-Term -- Class 2

    SciTech Connect

    Carr, Timothy R.; Green, Don W.; Willhite, G. Paul

    1999-07-08

    This report describes progress during the third year of the project entitled ''Improved Oil Recovery in Mississippian Carbonate Reservoirs in Kansas''. This project funded under the Department of Energy's Class 2 program targets improving the reservoir performance of mature oil fields located in shallow shelf carbonate reservoirs. The focus of this project is development and demonstration of cost-effective reservoir description and management technologies to extend the economic life of mature reservoirs in Kansas and mid-continent. The project introduced a number of potentially useful technologies, and demonstrated these technologies in actual oil field operations. Advanced technology was tailored specifically to the scale appropriate to the operations of Kansas producers. An extensive technology transfer effort is ongoing. Traditional technology transfer methods (e.g., publications and workshops) are supplemented with a public domain relational database and an online package of project results that is available through the Internet. The goal is to provide the independent complete access to project data, project results and project technology on their desktop. Included in this report is a summary of significant project results at the demonstration site (Schaben Field, Ness County, Kansas). The value of cost-effective techniques for reservoir characterization and simulation at Schaben Field were demonstrated to independent operators. All major operators at Schaben have used results of the reservoir management strategy to locate and drill additional infill locations. At the Schaben Demonstration Site, the additional locations resulted in incremental production increases of 200 BOPD from a smaller number of wells.

  20. The use of coiled tubing during matrix acidizing of carbonate reservoirs

    SciTech Connect

    Thomas, R.L.; Milne, A.

    1995-10-01

    A laboratory and field study directed at improved well performance of horizontal wells is discussed. During the study, several wells were matrix acidized using bullhead and coiled tubing placement techniques. The study performed in carbonate reservoirs indicates acid placed with coiled tubing diverted with foam provides excellent zone coverage and damage removal. Conventional bullhead techniques do not result in effective damage removal. The study emphasizes the evaluation of the treatment results and the development of improved acidizing techniques. Laboratory simulations of matrix acidizing indicate proper placement techniques are essential. This observation is supported by field data in oil wells completed in carbonate reservoirs. The key to successful damage removal is (1) the placement of acid via coiled tubing and (2) proper diversion. Production logging and well performance data support this claim. The proposed treatment is applicable in both horizontal and vertical wells completed in carbonate reservoirs.

  1. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. Quarterly technical progress report, 3rd quarter, 1994

    SciTech Connect

    Wehner, S.; Smith, V.; Cole, R.; Brugman, B.; Vogt, J.

    1994-10-18

    The principal objective of the Central Vacuum Unit (CVU) CO{sub 2} Huff-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the CO{sub 2} H-n-P process, coupled with the CVU reservoir characterization components will determine if this process is technically and economically feasible for field implementation. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of Energy`s (DOE) objective of increasing domestic oil production and deferring the abandonment of shallow shelf carbonate (SSC) reservoirs. Texaco Exploration and Production Inc`s. (TEPI) long-term plans are to implement a full-scale miscible CO{sub 2} project in the CVU. However, the current market precludes acceleration of such a capital intensive project. The DOE partnership provides some relief to the associated R and D risks, allowing TEPI to evaluate a proven Gulf-coast sandstone technology in a waterflooded carbonate environment. Technical progress is described on the following studies: Porosity and permeability relationships; Initial water saturation and oil-water contact; Geostatistical realization; and Parametric simulation.

  2. Facies dimensions within carbonate reservoirs - guidelines from satellite images of modern analogs

    SciTech Connect

    Harris, P.M.; Kowalik, W.S.

    1995-08-01

    Modern analogs illustrate the distribution of carbonate facies within an overall depositional setting and can be an integral part of a subsurface geologic model in indicating the dimensions, trend, and interrelationships of facies that might be related to reservoir and non-reservoir distribution. Satellite images from several modern carbonate areas depict the geologic characteristics that can be expected in ancient shallow-water settings. Isolated carbonate platforms- the Bahamas, Caicos Platform in the British West Indies, Chinchorro Bank offshore of Yucatan, and portions of the Belize area; Ramp-style shelf-to-basin transitions - Abu Dhabi and northern Yucatan; Rimmed shelf margins - South Florida, portions of Belize, and the Great Barrier Reef of Australia; Broad, deep shelf lagoons - the Great Barrier Reef and Belize; Reef variability - South Florida, the Bahamas, Caicos, Northern Yucatan, and Abu Dhabi; Shallow lagoon/tidal flat settings - South Florida, the Bahamas, Caicos, Northern Yucatan, Shark Bay in Western Australia, Abu Dhabi; Mixed carbonate and siliciclastic depostion - South Florida, Belize, the Great Barrier Reef, Shark Bay and Abu Dhabi. The geologic framework as illustrated by these areas is important at the development scale where lateral variation of porosity and permeability, i.e. reservoir quality, is commonly tied to facies changes and facies dimensions are required as input to reservoir models. The geologic framework is essential at the exploration scale for reservoir facies prediction and stratigraphic play concepts which are related directly to depositional facies patterns.

  3. Organic carbon isotope constraints on the dissolved organic carbon (DOC) reservoir at the Cryogenian-Ediacaran transition

    NASA Astrophysics Data System (ADS)

    Jiang, Ganqing; Wang, Xinqiang; Shi, Xiaoying; Zhang, Shihong; Xiao, Shuhai; Dong, Jin

    2010-10-01

    Prominent negative carbonate carbon isotope (δ 13C carb) anomalies from some Ediacaran successions are accompanied by invariant or decoupled organic carbon isotope (δ 13C org) values and have been interpreted as resulting from the remineralization of a large dissolved organic carbon (DOC) reservoir capable of buffering carbon isotopes of organic matter. This inferred oceanic DOC reservoir was thought to have initiated with the onset of Cryogenian glaciations (ca. 720 Ma) and lasted for millions of years until the late Ediacaran Period (< 560 Ma). Carbon isotope analyses of the basal Doushantuo Formation (ca. 635 Ma) in south China reveal that (1) the cap carbonate has δ 13C org around -26‰ (VPDB) and relatively low Δδ 13C (22 ± 2‰) and (2) the overlying organic-rich black shale and shaly dolostone have more negative δ 13C org (-28‰ to -35‰) and higher Δδ 13C (28‰-30‰). Both δ 13C carb and δ 13C org show a + 6‰ shift within a 4-m-thick interval overlying the Doushantuo cap carbonate. The δ 13C org values of the cap carbonate are associated with low TOC (mostly < 0.1%); their paleoceanographic significance requires further tests in other Ediacaran basins. The co-varying positive shift in δ 13C carb and δ 13C org following cap carbonate deposition is best interpreted as resulting from a rapid increase in organic carbon burial, which may have resulted in the rise of oxygen and heralded the first appearance of animals a few meters above the Doushantuo cap carbonate. The data suggest that a large oceanic DOC reservoir did not exist in the early Ediacaran ocean. Excess oceanic DOC required to explain the Ediacaran Shuram and upper Doushantuo δ 13C excursions, if it existed, had to be developed during the Ediacaran Period after cap carbonate deposition.

  4. Observational evidence for an active surface reservoir of solid carbon dioxide on Mars.

    PubMed

    Malin, M C; Caplinger, M A; Davis, S D

    2001-12-07

    High-resolution images of the south polar residual cap of Mars acquired in 1999 and 2001 show changes in the configuration of pits, intervening ridges, and isolated mounds. Escarpments have retreated 1 to 3 meters in 1 martian year, changes that are an order of magnitude larger than can be explained by the sublimation of water ice, but close to what is expected for sublimation of carbon dioxide ice. These observations support a 35-year-old conjecture that Mars has a large surface reservoir of solid carbon dioxide. The erosion implies that this reservoir is not in equilibrium with the present environment and that global climate change is occurring on Mars.

  5. Advanced Characterization of Fractured Reservoirs in Carbonate Rocks: The Michigan Basin

    SciTech Connect

    Wood, James R.; Harrison, William B.

    2000-10-24

    The main objective of this project is for a university-industry consortium to develop a comprehensive model for fracture carbonate reservoirs based on the ''data cube'' concept using the Michigan Basin as a prototype. This project combined traditional historical data with 2D and 3D seismic data as well as data from modern logging tools in a novel way to produce a new methodology for characterizing fractured reservoirs in carbonate rocks. Advanced visualization software was used to fuse the data and to image it on a variety of scales, ranging from basin-scale to well-scales.

  6. Advanced Characterization of Fractured Reservoirs in Carbonate Rocks: The Michigan Basin

    SciTech Connect

    Wood, J.R.; Harrison, W.B.

    2001-01-22

    The main objective of this project is for a university-industry consortium to develop a comprehensive model for fracture carbonate reservoirs based on the ''data cube'' concept using the Michigan Basin as a prototype. This project combined traditional historical data with 2D and 3D seismic data as well as data from modern logging tools in a novel way to produce a new methodology for characterizing fractured reservoirs in carbonate rocks. Advanced visualization software was used to fuse the data and to image it on a variety of scales, ranging from basin-scale to well-scales.

  7. Reservoir potential of carbonate rocks in the Kutai Basin region, East Kalimantan, Indonesia

    NASA Astrophysics Data System (ADS)

    Alam, H.; Paterson, D. W.; Syarifuddin, N.; Busono, I.; Corbin, S. G.

    1999-04-01

    Fifteen percent of the exploration wells drilled in the Kutai Basin region were targeted for stratigraphic play-types. Carbonate reservoirs comprise almost 70% of the objectives in these stratigraphic plays. There was need for a better understanding of the carbonate reservoir potential in the region. Accordingly, this study was carried out. The distribution, depositional environment as well as factors controlling the quality of carbonate reservoirs are reviewed and analyzed. Carbonate reservoirs in the study area can be found sparsely throughout the Kutai Basin. Carbonates range in age from Oligocene (Bebulu limestone) to Late Miocene (Dian limestone). The main constituents of these carbonate build-ups are platy-corals, encrusting red algae and larger benthonic foraminifera. Most of the carbonates were deposited in a shallow marine environment (inner to middle shelf) during rises in relative sea level. Highstand system tracts are characterized by well-developed carbonate facies-belts. The carbonate build-ups generally occur as isolated bedded mounds, from a few feet up to 1000 ft in thickness. The preservation of primary porosity is generally poor due to diagenetic processes during burial history, particularly the infilling of pores by non-ferroan calcite cement. The development of secondary porosity is limited, due to the retardation of subsurface fluid flow by non-permeable layers, and the absence of solution effects due to sub-aerial exposure and karstification. Preserved porosities are mainly present as vugs, best developed in coarse-grained shelf-margin facies, which may not have subsequently been completely filled by calcite cement. Early hydrocarbon migration may retard the diagenetic processes and preserve the primary carbonate porosity.

  8. Geological and reservoir characterization of shallow-shelf carbonate fields, Southern Paradox Basin, Utah

    SciTech Connect

    Chidsey, T.C. Jr.; Eby, D.E.

    1996-12-31

    The Paradox basin of Utah, Colorado, and Arizona contains nearly 100 small oil fields producing from carbonate mounds within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to three wells with primary per field production ranging from 700 MBO to 2 MMBO at a 15-20% recovery rate. Five fields (Anasazi, Mule, Blue Hogan, Heron North, and Runway) within the Navajo Nation of southeastern Utah have been evaluated for CO{sub 2}-flood projects based upon geological characterization and reservoir modeling. Conventional cores from the five fields show that three compositional reservoir types are present: (1) phylloid algal, (2) bioclastic calcarenite, and (3) bryozoan-dominated. Phylloid algal mounds are abundant in four of the five fields, and exhibit the best overall porosity and permeability. This mound type developed where shallow water depths and low energy allowed establishment of calcareous algal colonies possibly on paleohighs. The principal reservoir rock is algal bafflestone composed mostly of the phylloid Ivanovia and occasionally dolomitized. The Heron North field is a bioclastic calcarenite reservoir. It represents high-energy conditions resulting in carbonate beaches developed over foreshore carbonate rubble. The principal reservoir rocks are grainstones and rudstones having grain-selective dissolution and complete dolomitization. Bryozoan-dominated mounds present in Runway field developed in quiet, below wave-base settings that appear to be localized along Mississippian fault blocks trends. The principal reservoir rocks are bindstone and framestone with no dolomitization. The resulting model suggests that CO{sub 2} miscible flooding of these and other small carbonate reservoirs in the Paradox basin could significantly increase ultimate recovery of oil.

  9. Geological and reservoir characterization of shallow-shelf carbonate fields, Southern Paradox Basin, Utah

    SciTech Connect

    Chidsey, T.C. Jr. ); Eby, D.E. )

    1996-01-01

    The Paradox basin of Utah, Colorado, and Arizona contains nearly 100 small oil fields producing from carbonate mounds within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to three wells with primary per field production ranging from 700 MBO to 2 MMBO at a 15-20% recovery rate. Five fields (Anasazi, Mule, Blue Hogan, Heron North, and Runway) within the Navajo Nation of southeastern Utah have been evaluated for CO[sub 2]-flood projects based upon geological characterization and reservoir modeling. Conventional cores from the five fields show that three compositional reservoir types are present: (1) phylloid algal, (2) bioclastic calcarenite, and (3) bryozoan-dominated. Phylloid algal mounds are abundant in four of the five fields, and exhibit the best overall porosity and permeability. This mound type developed where shallow water depths and low energy allowed establishment of calcareous algal colonies possibly on paleohighs. The principal reservoir rock is algal bafflestone composed mostly of the phylloid Ivanovia and occasionally dolomitized. The Heron North field is a bioclastic calcarenite reservoir. It represents high-energy conditions resulting in carbonate beaches developed over foreshore carbonate rubble. The principal reservoir rocks are grainstones and rudstones having grain-selective dissolution and complete dolomitization. Bryozoan-dominated mounds present in Runway field developed in quiet, below wave-base settings that appear to be localized along Mississippian fault blocks trends. The principal reservoir rocks are bindstone and framestone with no dolomitization. The resulting model suggests that CO[sub 2] miscible flooding of these and other small carbonate reservoirs in the Paradox basin could significantly increase ultimate recovery of oil.

  10. A method for the assessment of long-term changes in carbon stock by construction of a hydropower reservoir.

    PubMed

    Bernardo, Julio Werner Yoshioka; Mannich, Michael; Hilgert, Stephan; Fernandes, Cristovão Vicente Scapulatempo; Bleninger, Tobias

    2017-09-01

    Sustainability of hydropower reservoirs has been questioned since the detection of their greenhouse gas (GHG) emissions which are mainly composed of carbon dioxide and methane. A method to assess the impact on the carbon cycle caused by the transition from a natural river system into a reservoir is presented and discussed. The method evaluates the long term changes in carbon stock instead of the current approach of monitoring and integrating continuous short term fluxes. A case study was conducted in a subtropical reservoir in Brazil, showing that the carbon content within the reservoir exceeds that of the previous landuse. The average carbon sequestration over 43 years since damming was 895 mg C m[Formula: see text] and found to be mainly due to storage of carbon in sediments. These results demonstrate that reservoirs have two opposite effects on the balance of GHGs. By storing organic C in sediments, reservoirs are an important carbon sink. On the other hand, reservoirs increase the flux of methane into the atmosphere. If the sediments of reservoirs could be used for long term C storage, reservoirs might have a positive effect on the balance of GHGs.

  11. Can We Make Use of Abandoned Land for Carbon Management and Ecosystem Restoration?

    NASA Astrophysics Data System (ADS)

    Yamagata, Y.; Shoyama, K.

    2014-12-01

    Potential conflicts between biodiversity conservation and climate-change mitigation can result in trade-offs in multiple-use land management. This study aimed to detect possible changes in land-use patterns in response to biodiversity conservation and climate-change mitigation measures and the effects on ecosystem services across a watershed. For that purpose, we have developed a new method to combine land-use change scenarios and ecosystem service assessments. We analyzed land-cover change based on past and future scenarios in the rural Kushiro watershed in northern Japan. The analysis showed that if no conservation measures were implemented and the timber and agricultural industry remained small until 2060, supporting and provisioning services would decline due to less land management. Although biodiversity conservation measures are predicted to improve three of the ecosystem services that we studied, carbon sequestration and timber production would be improved to a greater degree by climate-change mitigation measures. The greatest land-cover changes are likely to occur in the unprotected area around the middle reaches of the Kushiro River, and such changes could affect the provision of ecosystem services throughout the entire watershed. Thus, our findings indicate that land-use decisions for the middle reaches of the watershed are particularly important for managing the integrated ecosystem services of the entire watershed for the future.

  12. Seagrass meadows as a globally significant carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Mazarrasa, I.; Marbà, N.; Lovelock, C. E.; Serrano, O.; Lavery, P. S.; Fourqurean, J. W.; Kennedy, H.; Mateo, M. A.; Krause-Jensen, D.; Steven, A. D. L.; Duarte, C. M.

    2015-03-01

    There has been a growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the organic carbon (POC) stocks and accumulation rates and ignored the inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 402 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m sediments ranged between 3 and 1660 Mg PIC ha-1, with an average of 654 ± 24 Mg PIC ha-1, exceeding about 5 fold those of POC reported in previous studies. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of -8 ± 2 Mg PIC ha-1 degree-1 of latitude (GLM, p < 0.0003). Using PIC concentration and estimates of sediment accretion in seagrass meadows, mean PIC accumulation rates in seagrass sediments is 126.3 ± 0.7 g PIC m-2 y-1. Based on the global extent of seagrass meadows (177 000 to 600 000 km2), these ecosystems globally store between 11 and 39 Pg of PIC in the top meter of sediment and accumulate between 22 and 76 Tg PIC y-1, representing a significant contribution to the carbonate dynamics of coastal areas. Despite that these high rates of carbonate accumulation imply CO2 emissions from precipitation, seagrass meadows are still strong CO2 sinks as demonstrates the comparison of carbon (POC and POC) stocks between vegetated and adjacent un-vegetated sediments.

  13. Seismic estimation of porosity in the Permian San Andres carbonate reservoir, Welch Field, Dawson, County, Texas

    SciTech Connect

    Watts, G.P.; Hinterlong, G.D. )

    1996-01-01

    OXY and the DOE Are partners in a advanced technology demonstration project at OXY's West Welch Unit. Production is from a low permeability San Andres reservoir of Permian age similar to many shallow shelf carbonate reservoirs in the Permian Basin. The project involves the construction of a detailed geological model for numerical simulation to design and then conduct a CO[sub 2] flood of the reservoir. Depositional textures of the reservoir rock are highly variable from diagenesis, mostly anhydritic cementing, creating a highly complex pore system. Identification of the interwell reservoir continuity and flow units present the greatest challenge to the reservoir description. A 1993 vintage 3-D seismic survey with a bin spacing of 110[prime] by 165[prime] has been used to assist with the interwell reservoir description. The structure definition at the top and base of the reservoir have been accurately mapped with respect to the well data. Core and well log measurements of porosity, permeability and water saturation were computed and summed across the seismic reservoir interval. Measurements of amplitude, frequency and phase within the 3-D volume were summed across the reservoir interval. All seismic attributes were sampled to the wells and compared through scatterplots to the well log and core measurements. Excellent correlation between three seismic attributes and porosity has been documented. A deterministic method has been used to estimate porosity values at each seismic bin location. The method uses the seismic measurements to shape the geology between the wells while maintaining agreement with the well data at the well locations.

  14. Seismic estimation of porosity in the Permian San Andres carbonate reservoir, Welch Field, Dawson, County, Texas

    SciTech Connect

    Watts, G.P.; Hinterlong, G.D.

    1996-12-31

    OXY and the DOE Are partners in a advanced technology demonstration project at OXY`s West Welch Unit. Production is from a low permeability San Andres reservoir of Permian age similar to many shallow shelf carbonate reservoirs in the Permian Basin. The project involves the construction of a detailed geological model for numerical simulation to design and then conduct a CO{sub 2} flood of the reservoir. Depositional textures of the reservoir rock are highly variable from diagenesis, mostly anhydritic cementing, creating a highly complex pore system. Identification of the interwell reservoir continuity and flow units present the greatest challenge to the reservoir description. A 1993 vintage 3-D seismic survey with a bin spacing of 110{prime} by 165{prime} has been used to assist with the interwell reservoir description. The structure definition at the top and base of the reservoir have been accurately mapped with respect to the well data. Core and well log measurements of porosity, permeability and water saturation were computed and summed across the seismic reservoir interval. Measurements of amplitude, frequency and phase within the 3-D volume were summed across the reservoir interval. All seismic attributes were sampled to the wells and compared through scatterplots to the well log and core measurements. Excellent correlation between three seismic attributes and porosity has been documented. A deterministic method has been used to estimate porosity values at each seismic bin location. The method uses the seismic measurements to shape the geology between the wells while maintaining agreement with the well data at the well locations.

  15. Investigating physical controls on methane and carbon dioxide fluxes over reservoirs using the eddy covariance method-abstract

    EPA Science Inventory

    Reservoirs are a globally important source of carbon to the atmosphere. Several recent studies have found that both carbon dioxide (CO2) and methane (CH4) emissions from reservoirs are currently being underestimated by up to 50%. This underestimation is due to inadequate characte...

  16. Investigating physical controls on methane and carbon dioxide fluxes over reservoirs using the eddy covariance method-abstract

    EPA Science Inventory

    Reservoirs are a globally important source of carbon to the atmosphere. Several recent studies have found that both carbon dioxide (CO2) and methane (CH4) emissions from reservoirs are currently being underestimated by up to 50%. This underestimation is due to inadequate characte...

  17. Reservoir characters of the Ypresian carbonates, Western Libyan Offshore, Central Mediterranean Sea

    SciTech Connect

    Mriheel, I.Y.

    1995-08-01

    Significant hydrocarbon accumulations have been discovered in Western Libyan offshore in the Ypresian carbonate reservoirs of Jdeir Formation and Jirani Dolomite. The discoveries of hydrocarbons are mainly in structural traps where the Jdeir nummulitic facies and Jirani dolomitic facies B have been structured by salt domes or underlying positive fault blocks. This study investigates the relationship between environments of deposition, diagenesis and reservoir characters of the two main hydrocarbon producing units of the Jdeir and Jirani formations. Petrographic and petrophysical studies indicate that porosity in the Jirani Dolomite is related to diagenesis in meteoric environments, while in the Jdeir reservoir is the result of the environment of deposition and diagenesis. Excellent reservoir porosity of Jdeir nummulitic facies and Jirani dolomitic facies B is related to diagenesis in meteoric water during exposure to subaerial conditions which is considered to be due to lowering of sea level and possibly local uplifting.

  18. Greenhouse Gas Production From a Young Boreal Hydroelectric Reservoir (Eastern Canada): A Carbon Isotope Approach

    NASA Astrophysics Data System (ADS)

    Lalonde, A.; Helie, J.

    2007-12-01

    It is now accepted that boreal hydroelectric reservoirs and lakes produce greenhouse gases (GHG) mainly in the form of CO2. Much of the research has so far focused on old (> 20 year) reservoirs. However, the problems associated with a newly flooded reservoir are different because after flooding, salts and nutrients from the flooded soils are released into the water column (i.e. the reservoir's effect). It is anticipated that the CO2 fluxes should be higher in young reservoirs than in older ones, but little is known about their magnitude and their sources. The Eastmain-1 hydroelectric reservoir is a small reservoir of 603 km2 with a mean depth of 11.5m. Flooding began in November 2005 and ended in May 2006. The flooded area was covered with approximately 65% boreal forests, 21% rivers and lakes and 14% peatlands. Here, we make use stable carbon isotopes to constrain carbon sources and cycling in this disturbed environment. Ultimately, the study aims at estimating annual CO2 fluxes at the water-air interface of the reservoir. Sampling was performed four times (June 2006, August 2006, October 2006 and June 2007) to account for seasonality of the carbon cycle. Twelve sites were visited on the reservoir as well as a natural lake near the reservoir. Three sites were also sampled along a depth gradient. At each sampling site, in situ measurements included water and air temperatures, pH, alkalinity, wind speed, conductivity and dissolved oxygen content. Samples were collected for the analysis of dissolved organic and inorganic carbon (respectively DOC and DIC) and particulate organic carbon (POC) concentrations, for the analysis of the carbon isotopic compositions of DOC, DIC, POC and air CO2 at the water-air interface and finally for the C:N of DOM and POM. DOC concentrations are highest averaging 6.86±1.40 mg*l-1, DIC concentrations average 1.51±0.76 mg*l-1 and POC concentrations are up to 2 orders of magnitude lower averaging 0.036±0.018 mg*l-1. δ13C values of DOC

  19. Soil carbon sequestration or biofuel production: new land-use opportunities for mitigating climate over abandoned Soviet farmlands.

    PubMed

    Vuichard, Nicolas; Ciais, Philippe; Wolf, Adam

    2009-11-15

    Although the CO(2) mitigation potential of biofuels has been studied by extrapolation of small-scale studies, few estimates exist of the net regional-scale carbon balance implications of biofuel cultivations programs, either growing conventional biofuel crops or applying new advanced technologies. Here we used a spatially distributed process-driven model over the 20 Mha of recently abandoned agricultural lands of the Former Soviet Union to quantify the GHG mitigation by biofuel production from Low Input/High Diversity (LIHD) grass-legume prairies and to compare this GHG mitigation with the one of soil C sequestration as it currently occurs. LIHD has recently received a lot of attention as an emerging opportunity to produce biofuels over marginal lands leading to a good energy efficiency with minimal adverse consequences on food security and ecosystem services. We found that, depending on the time horizon over which one seeks to maximize the GHG benefit, the optimal time for implementing biofuel production shifts from "never" (short-term horizon) to "as soon as possible" (longer-term horizon). These results highlight the importance of reaching agreement a priori on the target time interval during which biofuels are expected to play a role within the global energy system, to avoid deploying biofuel technology over a time interval for which it has a detrimental impact on the GHG mitigation objective. The window of opportunity for growing LIHD also stresses the need to reduce uncertainties in soil C inputs, turnover, and soil organic matter stability under current and future climate and management practices.

  20. Characterization of a Miocene carbonate reservoir analog in Southern Mallorca (Balearic Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Vandeginste, V.; Camoin, G.; Eisenhauer, A.; Pézard, P.; Lapointe, P.

    2009-04-01

    Carbonate reservoirs contain more than half the world's oil reserves, including highly productive reservoirs in Cretaceous and Cenozoic carbonates from the Middle East and Southeastern Asia. They are usually characterized by the complexity both of their internal architecture and of the distribution of their diagenetic fabrics which hampers crosshole correlations at various scales, and predictions regarding flow paths and volumes of fluids. Reservoir analogs can have the advantage of easier accessibility and sampling and less severe diagenetic alteration. Their study often provides information complementary to the knowledge of hydrocarbon reservoirs and it leads to a better understanding of carbonate systems, important to make better predictions on other potential reservoirs. Significant advances can be made from joint research in natural laboratories integrating outcrops and shallow boreholes, with extensive control on geophysical, geological and petrophysical parameters. The southern part of the island of Mallorca appears as a natural laboratory where a direct comparison between outcrop and shallow subsurface datasets is the objective of the current study. This region is characterized both by spectacular outcrops, especially in the Cabo Blanco area, which were previously studied [e.g. 1], and by shallow holes, 100 m deep on average, that have been drilled especially at Can Roses, Ses Pastores and Ses Sitjoles, from west to east. This geographical extension of the study area provides the opportunity to better explore and understand the Miocene carbonate complex which comprises the Llucmajor platform. This study incorporates a wide range of analytical techniques to characterize the reservoir aspects, such as conventional microscopy of thin sections, XRD analysis, isotopic carbon and oxygen analysis, isotopic strontium dating analysis, petrophysical measurements, high-resolution borehole images and CT scan data. These techniques are used to unravel the sedimentology

  1. Seagrass meadows as a globally significant carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Mazarrasa, I.; Marbà, N.; Lovelock, C. E.; Serrano, O.; Lavery, P. S.; Fourqurean, J. W.; Kennedy, H.; Mateo, M. A.; Krause-Jensen, D.; Steven, A. D. L.; Duarte, C. M.

    2015-08-01

    There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 403 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m of sediment ranged between 3 and 1660 Mg PIC ha-1, with an average of 654 ± 24 Mg PIC ha-1, exceeding those of POC reported in previous studies by about a factor of 5. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of -8 ± 2 Mg PIC ha-1 per degree of latitude (general linear model, GLM; p < 0.0003). Using PIC concentrations and estimates of sediment accretion in seagrass meadows, the mean PIC accumulation rate in seagrass sediments is found to be 126.3 ± 31.05 g PIC m-2 yr-1. Based on the global extent of seagrass meadows (177 000 to 600 000 km2), these ecosystems globally store between 11 and 39 Pg of PIC in the top metre of sediment and accumulate between 22 and 75 Tg PIC yr-1, representing a significant contribution to the carbonate dynamics of coastal areas. Despite the fact that these high rates of carbonate accumulation imply CO2 emissions from precipitation, seagrass meadows are still strong CO2 sinks as demonstrated by the comparison of carbon (PIC

  2. Carbon stock estimation in the catchment of Kotli Bhel 1A hydroelectric reservoir, Uttarakhand, India.

    PubMed

    Kumar, Amit; Sharma, M P

    2016-12-01

    Constructions of dams/reservoirs all over the world are reported to emit significant amount of greenhouse gases (GHGs) and are considered as environmental polluters. Organic carbon is contributed by the forest in the catchment, part of soil organic carbon is transported through the runoffs to the reservoir and undergoes aerobic and anaerobic degradation with time to release GHGs to the atmosphere. Literature reveals that no work is available on the estimation of 'C' stock of trees of forest catchment for assessing/predicting the GHGs emissions from the reservoirs to atmosphere. To assess the GHGs emission potential of the reservoir, an attempt is made in the study to estimate the 'C' stock in the forest catchment of Kotli Bhel 1A hydroelectric reservoir located in Tehri Garhwal district of Uttarakhand, India. For this purpose, the selected area was categorized into the site-I, II and III along the Bhagirathi River based on type of forest available in the catchment. The total carbon density (TCD) of tree species of different forest types was calculated using diameter at breast height (dbh) and trees height. The results found that the TCD of forest catchment was found 76.96MgCha(-1) as the highest at the site-II and 29.93MgCha(-1) as lowest at site-I with mean of 51.50MgCha(-1). The estimated forest 'C' stock shall be used to know the amount of carbon present before and after construction of the dam and to predict net GHGs emissions. The results may be helpful to study the potential of a given reservoir to release GHG and its subsequent impacts on global warming/climate challenges. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Dam tailwaters compound the effects of reservoirs on the longitudinal transport of organic carbon in an arid river

    NASA Astrophysics Data System (ADS)

    Ulseth, A. J.; Hall, R. O., Jr.

    2015-04-01

    Reservoirs on rivers can disrupt organic carbon (OC) transport and transformation, but less is known how downstream river reaches directly below dams contribute to OC processing than reservoirs alone. We compared how reservoirs and their associated tailwaters affected OC quantity and quality by calculating particulate (P) OC and dissolved (D) OC fluxes, and measuring composition and bioavailability of DOC. We sampled the Yampa River near Maybell, Colorado, USA and the Green River above and below Fontenelle and Flaming Gorge reservoirs, and their respective tailwaters from early snowmelt to base flow hydrological conditions. In unregulated reaches (Yampa River, Green River above Fontenelle reservoir), DOC and POC concentrations increased with snowmelt discharge. POC and DOC concentrations also increased with stream discharge below Fontenelle reservoir, but there was no relationship between DOC and stream flow below Flaming Gorge reservoir. The annual load of POC was 3-fold lower below Fontenelle Reservoir and nearly 7-fold lower below Flaming Gorge reservoir, compared to their respective upstream sampling sites. DOC exported to downstream reaches from both reservoirs was less bioavailable, as measured with bioassays, than DOC upriver of the reservoirs. Lastly, tailwater reaches below the reservoirs generated OC, exporting 1.6-2.2 g C m-2 d-1 of OC to downstream ecosystems. Changes in total fluxes from upstream to downstream of reservoirs and their tailwaters do not represent the simultaneous transformation and production of OC, which may lead to the underestimation of the quantity of OC mineralized, transformed, or retained in coupled river-reservoir-tailwater ecosystems.

  4. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. Quarterly technical progress report, Fourth quarter 1995

    SciTech Connect

    Wehner, S.; Prieditis, J.

    1996-02-05

    The principle objective of the Central Vacuum Unit (CVU) CO{sub 2} Huff-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the CO{sub 2} H-n-P process, coupled with the CVU reservoir characterization components will determine if this process is technically and economically feasible for field implementation. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of Energy`s objective of increasing domestic oil production and deferring the abandonment of shallow shelf carbonate (SSC) reservoirs. Texaco Exploration and Production Inc`s. (TEPI) mid-term plans are to implement a full-scale miscible CO{sub 2} project in the CVU. TEPI has concluded all of the Tasks associated with the First Budget Period. The DOE approved the TEPI continuation application. Budget Period No. 2 is now in progress. Initial injection of CO{sub 2} began in November, and after a short shut-in period for the soak, the well was returned to production in late December, 1995.

  5. Application of Carbonate Reservoir using waveform inversion and reverse-time migration methods

    NASA Astrophysics Data System (ADS)

    Kim, W.; Kim, H.; Min, D.; Keehm, Y.

    2011-12-01

    Recent exploration targets of oil and gas resources are deeper and more complicated subsurface structures, and carbonate reservoirs have become one of the attractive and challenging targets in seismic exploration. To increase the rate of success in oil and gas exploration, it is required to delineate detailed subsurface structures. Accordingly, migration method is more important factor in seismic data processing for the delineation. Seismic migration method has a long history, and there have been developed lots of migration techniques. Among them, reverse-time migration is promising, because it can provide reliable images for the complicated model even in the case of significant velocity contrasts in the model. The reliability of seismic migration images is dependent on the subsurface velocity models, which can be extracted in several ways. These days, geophysicists try to obtain velocity models through seismic full waveform inversion. Since Lailly (1983) and Tarantola (1984) proposed that the adjoint state of wave equations can be used in waveform inversion, the back-propagation techniques used in reverse-time migration have been used in waveform inversion, which accelerated the development of waveform inversion. In this study, we applied acoustic waveform inversion and reverse-time migration methods to carbonate reservoir models with various reservoir thicknesses to examine the feasibility of the methods in delineating carbonate reservoir models. We first extracted subsurface material properties from acoustic waveform inversion, and then applied reverse-time migration using the inverted velocities as a background model. The waveform inversion in this study used back-propagation technique, and conjugate gradient method was used in optimization. The inversion was performed using the frequency-selection strategy. Finally waveform inversion results showed that carbonate reservoir models are clearly inverted by waveform inversion and migration images based on the

  6. CO{sub 2} huff-n-puff process in a light oil shallow carbonate reservoir. Annual report, January 1, 1996--December 31, 1996

    SciTech Connect

    Prieditis, J.; Wehner, S.

    1998-01-01

    The application of cyclic CO{sub 2}, often referred to as the CO{sub 2} Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO{sub 2} H-n-P process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital intensive miscible projects. Texaco Exploration & Production Inc. and the U.S. Department of Energy have teamed up in an attempt to develop the CO{sub 2} Huff-n-Puff process in the Grayburg and San Andres formations; a light oil, shallow shelf carbonate reservoir that exists throughout the Permian Basin. A significant amount of oil reserves are located in carbonate reservoirs. Specifically, the carbonates deposited in shallow shelf (SSC) environments make up the largest percentage of known reservoirs within the Permian Basin of North America. Many of these known resources have been under waterflooding operations for decades and are at risk of abandonment if crude oil recoveries cannot be economically enhanced. The selected site for this demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico. Miscible CO{sub 2} flooding is the process of choice for enhancing recovery of light oils and already accounts for over 12% of the Permian Basin`s daily production. There are significant probable reserves associated with future miscible CO{sub 2} projects. However, many are marginally economic at current market conditions due to large up-front capital commitments for a peak response which may be several years in the future. The resulting negative cash-flow is sometimes too much for an operator to absorb. The CO{sub 2} H-n-P process is being investigated as a near-term option to mitigate the negative cash-flow situation--allowing acceleration of inventoried miscible CO{sub 2} projects when coupled together.

  7. Dam tailwaters compound the effects of reservoirs on the longitudinal transport of organic carbon in an arid river

    NASA Astrophysics Data System (ADS)

    Ulseth, A. J.; Hall, R. O., Jr.

    2015-07-01

    Reservoirs on rivers can disrupt organic carbon (OC) transport and transformation, but less is known how river reaches directly below dams contribute to OC processing. We compared how reservoirs and their associated tailwaters affected OC quantity and quality by calculating particulate OC (POC) and dissolved OC (DOC) fluxes, and measuring composition and bioavailability of DOC. We sampled the Yampa River near Maybell, Colorado, USA, and the Green River above and below Fontenelle and Flaming Gorge reservoirs as well as their respective tailwaters from early snowmelt to base flow hydrological conditions. In unregulated reaches (Yampa River, Green River above Fontenelle reservoir), DOC and POC concentrations increased with snowmelt discharge. POC and DOC concentrations also increased with stream discharge below Fontenelle reservoir, but there was no relationship between DOC and stream flow below Flaming Gorge reservoir. The annual load of POC was 3-fold lower below Fontenelle Reservoir and nearly 7-fold lower below Flaming Gorge reservoir, compared to their respective upstream sampling sites. DOC exported to downstream reaches from both reservoirs was less bioavailable, as measured with bioassays, than DOC upriver of the reservoirs. Lastly, tailwater reaches below the reservoirs generated OC, exporting potentially 1.6-2.2 g C m-2 d-1 of OC to downstream ecosystems. Therefore, the effect of impounding rivers on C fluxes is greater than the impact of the reservoirs alone given the additive effect of tailwater reaches below dams, which may produce and export comparable amounts of likely autochthonous carbon to downstream reaches.

  8. Active CO2 Reservoir Management for Carbon Capture, Utilization, and Sequestration: Impact on Permitting, Monitoring, and Public Acceptance

    NASA Astrophysics Data System (ADS)

    Buscheck, T. A.; Chen, M.; Sun, Y.; Hao, Y.; Court, B.; Celia, M. A.; Wolery, T.; Aines, R. D.

    2011-12-01

    CO2 capture and sequestration (CCS) integrated with geothermal energy production in deep geological formations can play an important role in reducing CO2 emissions to the atmosphere and thereby mitigate global climate change. For industrial-scale CO2 injection in saline formations, pressure buildup can limit storage capacity and security. Active CO2 Reservoir Management (ACRM) combines brine production with CO2 injection to relieve pressure buildup, increase injectivity, manipulate CO2 migration, constrain brine leakage, and enable beneficial utilization of produced brine. Therefore, ACRM can be an enabler of carbon capture, utilization, and sequestration (CCUS). Useful products may include freshwater, cooling water, make-up water for pressure support in oil, gas, and geothermal reservoir operations, and geothermal energy production. Implementation barriers to industrial-scale CCS include concerns about (1) CO2 sequestration security and assurance, (2) pore-space competition with neighboring subsurface activities, (3) CO2 capture costs, and (4) water-use demands imposed by CCS operations, which is particularly important where water resources are already scarce. CCUS, enabled by ACRM, has the potential of addressing these barriers. Pressure relief from brine production can substantially reduce the driving force for potential CO2 and brine migration, as well as minimize interference with neighboring subsurface activities. Electricity generated from geothermal energy can offset a portion of the parasitic energy and financial costs of CCS. Produced brine can be used to generate freshwater by desalination technologies, such as RO, provide a source for saltwater cooling systems or be used as make-up water for oil, gas, or geothermal reservoir operations, reducing the consumption of valuable freshwater resources. We examine the impact of brine production on reducing CO2 and brine leakage. A volumetric balance between injected and produced fluids minimizes the spatial

  9. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SANANDRES RESERVOIR

    SciTech Connect

    Unknown

    2003-01-15

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO{sub 2}) stimulation treatments; (6) Hydraulic fracturing design and monitoring; (7) Mobility control agents.

  10. Tectonic control of the crustal organic carbon reservoir during the Precambrian

    NASA Technical Reports Server (NTRS)

    Des Marais, D. J.

    1994-01-01

    Carbon isotopic trends indicate that the crustal reservoir of reduced, organic carbon increased during the Proterozoic, particularly during periods of widespread continental rifting and orogeny. No long-term trends are apparent in the concentration of organic carbon in shales, cherts and carbonates. The age distribution of 261 sample site localities sampled for well-preserved sedimentary rocks revealed a 500-700-Ma periodicity which coincided with tectonic cycles. It is assumed that the numbers of sites are a proxy for mass of sediments. A substantial increase in the number of sites in the late Archean correlates with the first appearance between 2.9 and 2.5 Ga of extensive continental platforms and their associated sedimentation. It is proposed that the size of the Proterozoic crustal organic carbon reservoir has been modulated by tectonic control of the volume of sediments deposited in environments favorable for the burial and preservation of organic matter. Stepwise increases in this reservoir would have caused the oxidation state of the Proterozoic environment to increase in a stepwise fashion.

  11. Tectonic control of the crustal organic carbon reservoir during the Precambrian.

    PubMed

    Des Marais, D J

    1994-01-01

    Carbon isotopic trends indicate that the crustal reservoir of reduced, organic carbon increased during the Proterozoic, particularly during periods of widespread continental rifting and orogeny. No long-term trends are apparent in the concentration of organic carbon in shales, cherts and carbonates. The age distribution of 261 sample site localities sampled for well-preserved sedimentary rocks revealed a 500-700-Ma periodicity which coincided with tectonic cycles. It is assumed that the numbers of sites are a proxy for mass of sediments. A substantial increase in the number of sites in the late Archean correlates with the first appearance between 2.9 and 2.5 Ga of extensive continental platforms and their associated sedimentation. It is proposed that the size of the Proterozoic crustal organic carbon reservoir has been modulated by tectonic control of the volume of sediments deposited in environments favorable for the burial and preservation of organic matter. Stepwise increases in this reservoir would have caused the oxidation state of the Proterozoic environment to increase in a stepwise fashion.

  12. Tectonic control of the crustal organic carbon reservoir during the Precambrian

    NASA Technical Reports Server (NTRS)

    Des Marais, D. J.

    1994-01-01

    Carbon isotopic trends indicate that the crustal reservoir of reduced, organic carbon increased during the Proterozoic, particularly during periods of widespread continental rifting and orogeny. No long-term trends are apparent in the concentration of organic carbon in shales, cherts and carbonates. The age distribution of 261 sample site localities sampled for well-preserved sedimentary rocks revealed a 500-700-Ma periodicity which coincided with tectonic cycles. It is assumed that the numbers of sites are a proxy for mass of sediments. A substantial increase in the number of sites in the late Archean correlates with the first appearance between 2.9 and 2.5 Ga of extensive continental platforms and their associated sedimentation. It is proposed that the size of the Proterozoic crustal organic carbon reservoir has been modulated by tectonic control of the volume of sediments deposited in environments favorable for the burial and preservation of organic matter. Stepwise increases in this reservoir would have caused the oxidation state of the Proterozoic environment to increase in a stepwise fashion.

  13. Calibration of NMR well logs from carbonate reservoirs with laboratory NMR measurements and μXRCT

    DOE PAGES

    Mason, Harris E.; Smith, Megan M.; Hao, Yue; ...

    2014-12-31

    The use of nuclear magnetic resonance (NMR) well log data has the potential to provide in-situ porosity, pore size distributions, and permeability of target carbonate CO₂ storage reservoirs. However, these methods which have been successfully applied to sandstones have yet to be completely validated for carbonate reservoirs. Here, we have taken an approach to validate NMR measurements of carbonate rock cores with independent measurements of permeability and pore surface area to volume (S/V) distributions using differential pressure measurements and micro X-ray computed tomography (μXRCT) imaging methods, respectively. We observe that using standard methods for determining permeability from NMR data incorrectlymore » predicts these values by orders of magnitude. However, we do observe promise that NMR measurements provide reasonable estimates of pore S/V distributions, and with further independent measurements of the carbonate rock properties that universally applicable relationships between NMR measured properties may be developed for in-situ well logging applications of carbonate reservoirs.« less

  14. Adaptive neuro fuzzy inference system for compressional wave velocity prediction in a carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Zoveidavianpoor, Mansoor; Samsuri, Ariffin; Shadizadeh, Seyed Reza

    2013-02-01

    Compressional-wave (Vp) data are key information for estimation of rock physical properties and formation evaluation in hydrocarbon reservoirs. However, the absence of Vp will significantly delay the application of specific risk-assessment approaches for reservoir exploration and development procedures. Since Vp is affected by several factors such as lithology, porosity, density, and etc., it is difficult to model their non-linear relationships using conventional approaches. In addition, currently available techniques are not efficient for Vp prediction, especially in carbonates. There is a growing interest in incorporating advanced technologies for an accurate prediction of lacking data in wells. The objectives of this study, therefore, are to analyze and predict Vp as a function of some conventional well logs by two approaches; Adaptive Neuro-Fuzzy Inference System (ANFIS) and Multiple Linear Regression (MLR). Also, the significant impact of selected input parameters on response variable will be investigated. A total of 2156 data points from a giant Middle Eastern carbonate reservoir, derived from conventional well logs and Dipole Sonic Imager (DSI) log were utilized in this study. The quality of the prediction was quantified in terms of the mean squared error (MSE), correlation coefficient (R-square), and prediction efficiency error (PEE). Results show that the ANFIS outperforms MLR with MSE of 0.0552, R-square of 0.964, and PEE of 2%. It is posited that porosity has a significant impact in predicting Vp in the investigated carbonate reservoir.

  15. Research on carbonate reservoir interwell connectivity based on a modified diffusivity filter model

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Yao, Jun; Li, Yang; Lv, Aimin

    2017-05-01

    According to the solution of dual-porosity model, a diffusivity filter model of carbonate reservoir was established, which can effectively illustrate the injection signal attenuation and lag characteristic. The interwell dynamic connectivity inversion model combines a multivariate linear regression (MLR) analysis with a correction coefficient to eliminate the effect of fluctuating bottom-hole pressure (BHP). The modified MLR model was validated by synthetic field with fluctuating BHP. The method was applied to Tahe oilfield which showed that the inversion result was reliable. The interwell dynamic connectivity coefficients could reflect the real interwell connectivity of reservoir. The method is easy to use and proved to be effective in field applications.

  16. Injection of liquid carbon dioxide into a reservoir partially saturated with methane hydrate

    NASA Astrophysics Data System (ADS)

    Shagapov, V. Sh.; Khasanov, M. K.; Musakaev, N. R.

    2016-11-01

    A mathematical model is proposed to describe methane-carbon dioxide replacement in gas hydrate by injecting liquid carbon dioxide into a porous medium initially saturated with methane and its hydrate. Self-similar solutions of the axisymmetric problems are constructed that describe the distribution of the main parameters of the reservoir. It is shown that there exist solutions according to which the process can occur both with and without boiling of carbon dioxide. Diagrams of the existence of each type of solution are constructed.

  17. SCREENING METHODS FOR SELECTION OF SURFACTANT FORMULATIONS FOR IOR FROM FRACTURED CARBONATE RESERVOIRS

    SciTech Connect

    William A. Goddard III; Yongchun Tang; Patrick Shuler; Mario Blanco; Yongfu Wu; Seung Soon Jang

    2005-07-01

    This topical report presents details of the laboratory work performed to complete Task 1 of this project; developing rapid screening methods to assess surfactant performance for IOR (Improved Oil Recovery) from fractured carbonate reservoirs. The desired outcome is to identify surfactant formulations that increase the rate and amount of aqueous phase imbibition into oil-rich, oil-wet carbonate reservoir rock. Changing the wettability from oil-wet to water-wet is one key to enhancing this water-phase imbibition process that in turn recovers additional oil from the matrix portion of a carbonate reservoir. The common laboratory test to evaluate candidate surfactant formulations is to measure directly the aqueous imbibition rate and oil recovery from small outcrop or reservoir cores, but this procedure typically requires several weeks. Two methods are presented here for the rapid screening of candidate surfactant formulations for their potential IOR performance in carbonate reservoirs. One promising surfactant screening protocol is based on the ability of a surfactant solution to remove aged crude oil that coats a clear calcite crystal (Iceland Spar). Good surfactant candidate solutions remove the most oil the quickest from the chips, plus change the apparent contact angle of the remaining oil droplets on the surface that thereby indicate increased water-wetting. The other fast surfactant screening method is based on the flotation behavior of powdered calcite in water. In this test protocol, first the calcite power is pre-treated to make the surface oil-wet. The next step is to add the pre-treated powder to a test tube and add a candidate aqueous surfactant formulation; the greater the percentage of the calcite that now sinks to the bottom rather than floats, the more effective the surfactant is in changing the solids to become now preferentially water-wet. Results from the screening test generally are consistent with surfactant performance reported in the literature.

  18. Pore Type Classification on Carbonate Reservoir in Offshore Sarawak using Rock Physics Model and Rock Digital Images

    NASA Astrophysics Data System (ADS)

    Lubis, L. A.; Harith, Z. Z. T.

    2014-03-01

    It has been recognized that carbonate reservoirs are one of the biggest sources of hydrocarbon. Clearly, the evaluation of these reservoirs is important and critical. For rigorous reservoir characterization and performance prediction from geophysical measurements, the exact interpretation of geophysical response of different carbonate pore types is crucial. Yet, the characterization of carbonate reservoir rocks is difficult due to their complex pore systems. The significant diagenesis process and complex depositional environment makes pore systems in carbonates far more complicated than in clastics. Therefore, it is difficult to establish rock physics model for carbonate rock type. In this paper, we evaluate the possible rock physics model of 20 core plugs of a Miocene carbonate platform in Central Luconia, Sarawak. The published laboratory data of this area were used as an input to create the carbonate rock physics models. The elastic properties were analyzed to examine the validity of an existing analytical carbonate rock physics model. We integrate the Xu-Payne Differential Effective Medium (DEM) Model and the elastic modulus which was simulated from a digital carbonate rock image using Finite Element Modeling. The results of this integration matched well for the separation of carbonate pore types and sonic P-wave velocity obtained from laboratory measurement. Thus, the results of this study show that the integration of rock digital image and theoretical rock physics might improve the elastic properties prediction and useful for more advance geophysical techniques (e.g. Seismic Inversion) of carbonate reservoir in Sarawak.

  19. Amplitude map analysis using forward modeling in sandstone and carbonate reservoirs

    SciTech Connect

    Neff, D.B. )

    1993-10-01

    The extent to which seismic amplitude maps can contribute to the analysis of hydrocarbon reservoirs was investigated for clastic and carbonate reservoirs worldwide. By using a petrophysical-based, forward modeling process called incremental pay thickness (IPT) modeling, five lithology types were quantitatively analyzed for the interplay of seismic amplitude versus lithology, porosity, hydrocarbon pore fluid saturation, bedding geometries, and reservoir thickness. The studies identified three common tuning curve shapes (concave, convex, and bilinear) that were primarily dependent upon the lithology model type and the average net porosity therein. While the reliability of pay and porosity predictions from amplitude maps varied for each model type, all analyses showed a limited thickness range for which amplitude data could successfully predict net porosity thickness or hydrocarbon pore volume. The investigation showed that systematic forward modeling is required before amplitude maps can be properly interpreted.

  20. Val Verde Basin: Thrusted Strawn (Pennsylvanian) carbonate reservoirs, Pakenham Field area

    SciTech Connect

    Montgomery, S.L.

    1996-07-01

    An important target of recent exploration in the Val Verde basin of southwestern Texas has been thrusted Pennsylvanian (Desmoinesian) carbonates along the leading edge of the Ouachita front. These reservoirs produce gas and condensate at significant rates from fractured limestones, which were deposited in a variety of environments and later complexly juxtaposed during thrusting. Improvements in seismic imaging capabilities, particularly associated with the introduction of two-dimension (2-D) swath and three-dimensional (3-D) surveys, have allowed accurate mapping of the thrust front and have resulted in revised interpretations of basin structure and history. These data highlight the existence of multiple reservoirs at separate structural levels. Strawn reservoirs are discussed in relation to the Pakenham field area, northwestern Terrell County.

  1. Biogenic manganese oxides as reservoirs of organic carbon and proteins in terrestrial and marine environments.

    PubMed

    Estes, E R; Andeer, P F; Nordlund, D; Wankel, S D; Hansel, C M

    2017-01-01

    Manganese (Mn) oxides participate in a range of interactions with organic carbon (OC) that can lead to either carbon degradation or preservation. Here, we examine the abundance and composition of OC associated with biogenic and environmental Mn oxides to elucidate the role of Mn oxides as a reservoir for carbon and their potential for selective partitioning of particular carbon species. Mn oxides precipitated in natural brackish waters and by Mn(II)-oxidizing marine bacteria and terrestrial fungi harbor considerable levels of organic carbon (4.1-17.0 mol OC per kg mineral) compared to ferromanganese cave deposits which contain 1-2 orders of magnitude lower OC. Spectroscopic analyses indicate that the chemical composition of Mn oxide-associated OC from microbial cultures is homogeneous with bacterial Mn oxides hosting primarily proteinaceous carbon and fungal Mn oxides containing both protein- and lipopolysaccharide-like carbon. The bacterial Mn oxide-hosted proteins are involved in both Mn(II) oxidation and metal binding by these bacterial species and could be involved in the mineral nucleation process as well. By comparison, the composition of OC associated with Mn oxides formed in natural settings (brackish waters and particularly in cave ferromanganese rock coatings) is more spatially and chemically heterogeneous. Cave Mn oxide-associated organic material is enriched in aliphatic C, which together with the lower carbon concentrations, points to more extensive microbial or mineral processing of carbon in this system relative to the other systems examined in this study, and as would be expected in oligotrophic cave environments. This study highlights Mn oxides as a reservoir for carbon in varied environments. The presence and in some cases dominance of proteinaceous carbon within the biogenic and natural Mn oxides may contribute to preferential preservation of proteins in sediments and dominance of protein-dependent metabolisms in the subsurface biosphere.

  2. Exploration model for shallow Silurian (Kankakee) carbonate reservoirs in western Illinois

    SciTech Connect

    Crockett, J.E.; Seyler, B.J.; Whitaker, S.

    1987-09-01

    Reservoirs in shallow (600-650 ft deep) basal Silurian Kankakee carbonates at Buckhorn consolidated, Siloam, and Kellerville oil fields in western Illinois have produced nearly 2 million bbl of oil, but were developed essentially by random drilling. A new exploration model that combines lithologic studies and isopach mapping has been developed at the Illinois State Geological Survey. Isopach mapping of Silurian and Devonian rocks between an organic facies in the Mississippian-Devonian New Albany Shale and the top of the Ordovician Maquoketa Shale reveals thickened sequences that coincide with most of the oil fields. These thickened intervals apparently reflect subtle paleovalleys eroded into the Maquoketa shale during the Ordovician-Silurian hiatus. During the initial Silurian marine transgression, these paleovalleys at the base of the Kankakee were filled with carbonates to form the thickened sequences. Differential erosion at the top of the Kankakee does not satisfactorily explain the locally thickened sequences in the Kankakee. Lithologic studies suggest that subsurface fluid flows concentrated along these paleovalleys contributed to subsequent diagenesis of valleyfill carbonates. Diagenetic alteration of these carbonates resulted in development of basal Kankakee reservoirs within the paleovalleys. This concept of Kankakee reservoirs occurring within paleovalleys at the Ordovician-Silurian unconformity is a new exploration model that can aid in the search for similar traps in western Illinois.

  3. Intrashelf basins: A geologic model for source-bed and reservoir facies deposition within carbonate shelves

    SciTech Connect

    Grover, G. Jr. )

    1993-09-01

    Intrashelf basins (moats, inshore basins, shelf basins, differentiated shelf, and deep-water lagoons of others) are depressions of varying sizes and shapes that occur within tectonically passive and regionally extensive carbonate shelves. Intrashelf basins grade laterally and downdip (seaward) into shallow-water carbonates of the regional shelf, are separated from the open marine basin by the shelf margin, and are largely filled by fine-grained subtidal sediments having attributes of shallow- and deeper water sedimentation. These basins are commonly fringed or overlain by carbonate sands, reefs, or buildups. These facies may mimic those that occur along the regional shelf margin, and they can have trends that are at a high angle to that of the regional shelf. Intrashelf basins are not intracratonic basins. The history of most intrashelf basins is a few million to a few tens of million of years. Examples of intrashelf basins are known throughout the Phanerozoic; the southern portion of the Holocene Belize shelf is a modern example of an intrashelf basin. Two types of intrashelf basins are recognized. Coastal basins pass updip into coastal clastics of the craton with the basin primarily filled by fine clastics. Shelf basins occur on the outer part of the shelf, are surrounded by shallow-water carbonate facies, and are filled by peloidal lime mud, pelagics, and argillaceous carbonates. Intrashelf basins are commonly the site of organic-rich, source-bed deposition, resulting in the close proximity of source beds and reservoir facies that may fringe or overlie the basin. Examples of hydrocarbon-charged reservoirs that were sourced by an intrashelf basin include the Miocene Bombay High field, offshore India; the giant Jurassic (Arab-D) and Cretaceous (Shuaiba) reservoirs of the Arabian Shelf; the Lower Cretaceous Sunniland trend, South Florida basin; and the Permian-Pennsylvanian reservoirs surrounding the Tatum basin in southeastern New Mexico.

  4. Investigating Physical Controls on Methane and Carbon Dioxide Fluxes over Reservoirs Using the Eddy Covariance Method

    NASA Astrophysics Data System (ADS)

    Waldo, S.; Beaulieu, J. J.; Walker, J. T.

    2016-12-01

    Reservoirs are a globally important source of carbon to the atmosphere. Several recent studies have found that both carbon dioxide (CO2) and methane (CH4) emissions from reservoirs are currently being underestimated by up to 50%. This underestimation is due to inadequate characterization of both spatial variability (e.g. ebullition and CO2 surface water concentration hot spots) and temporal variability (e.g. diurnal patterns, seasonal differences, and pulses driven by weather events or other disturbances). Use of the eddy covariance technique to measure CO2 and CH4 fluxes over reservoirs can help address the issues of spatial and temporal coverage. Here we present results from two eddy covariance measurement campaigns monitoring CO2 and CH4 fluxes over reservoirs in southwestern Ohio, US. The first campaign examined the effects of water level drawdown on reservoir CH4 ebullition. The eddy covariance results showed a clear response of CH4 emissions to the change in water level, increasing from a baseline of 3440 mg CH4 m-2 d-1 to a maximum of 6740 mg CH4 m-2 d-1 during the drawdown. These results agreed well with the emission rates measured via bubble samplers deployed in the vicinity of the tower. Conversely, the CO2 fluxes did not show a strong response to the drawdown. The eddy covariance system was deployed for a longer period of time during a second campaign at a mid-sized (2.4 km2) lake. Analyses of diurnal patterns in CO2 and CH4 emissions as well as emission response to synoptic events will be presented. Our results contribute to the ongoing effort to better interpret and scale-up CH4 and CO2 emissions from reservoirs.

  5. Patterns of changes in oil properties in complex constructions for carbonate reservoirs

    NASA Astrophysics Data System (ADS)

    Morozov, Vladimir P.; Plotnikova, Irina N.; Nosova, Fidania F.; Pronin, Nikita V.; Nosova, Julia G.

    2014-05-01

    The objects of this research are carbonate reservoirs with non-uniform lithology and filtration-volumetric parameters. The oil under study is heavy ( 0.924 g/cm3). Our research methods include the following: studying of filtration-volumetric parameters in rock samples, performing the thermal and geochemical studies of fluids . Thermal and geochemical studies performed on core samples and on fluids extracted from sediments of Bashkirian sub-panel of a 1985 well in Akansky field showed that oil properties (namely its group composition) are not constant and uniform throughout the deposit but depend on the structure of the pore space, on the porosity, and the size of pore channels. In particular, we found out that oil that saturates large pores and cavities contains less oil fractions and more resins and asphaltenes. The fine pores of the rock matrix are saturated with lighter petroleum hydrocarbons, which predominantly have oils while the percentage of asphaltenes decreases. These patterns can be explained by the process of chromatography (separation) of oil during its migration and filtration through some porous environments while filling up the collector and forming deposits. Assuming that petroleum is a colloidal solution where light hydrocarbons serve as solvents, and resin- asphaltene colloidal particles are the dissolved part, the process of filling the pores can be represented as follows. Under the influence of external forces and as a result of spreading in a porous environment, oil, when entering the collector, is subjected chromatography - the lightest and easily movable hydrocarbons (solvents) penetrate into finer pore channels (including the thinnest pores and micro cracks of the rock matrix), while the resinous asphaltene part dissolved in oil remains in the large pores and cavities. Thus, the distribution of oil in carbonate reservoir of Bashkirian sub-panel is as follows: rock matrix and its low porosity layers are filled with lighter oil, while heavier

  6. Stable isotope mass balances versus concentration differences of dissolved inorganic carbon - implications for tracing carbon turnover in reservoirs.

    PubMed

    Barth, Johannes A C; Mader, Michael; Nenning, Franziska; van Geldern, Robert; Friese, Kurt

    2017-08-01

    The aim of this study was to identify sources of carbon turnover using stable isotope mass balances. For this purpose, two pre-reservoirs in the Harz Mountains (Germany) were investigated for their dissolved and particulate carbon contents (dissolved inorganic carbon (DIC), dissolved organic carbon, particulate organic carbon) together with their stable carbon isotope ratios. DIC concentration depth profiles from March 2012 had an average of 0.33 mmol L(-1). Increases in DIC concentrations later on in the year often corresponded with decreases in its carbon isotope composition (δ(13)CDIC) with the most negative value of -18.4 ‰ in September. This led to a carbon isotope mass balance with carbon isotope inputs of -28.5 ‰ from DOC and -23.4, -31.8 and -30.7 ‰ from algae, terrestrial and sedimentary matter, respectively. Best matches between calculated and measured DIC gains were achieved when using the isotope composition of algae. This shows that this type of organic material is most likely responsible for carbon additions to the DIC pool when its concentrations and δ(13)CDIC values correlate negatively. The presented isotope mass balance is transferable to other surface water and groundwater systems for quantification of organic matter turnover.

  7. High-Throughput Carbon Substrate Profiling of Mycobacterium ulcerans Suggests Potential Environmental Reservoirs

    PubMed Central

    Militello, Muriel; Drancourt, Michel

    2017-01-01

    Background Mycobacterium ulcerans is a close derivative of Mycobacterium marinum and the agent of Buruli ulcer in some tropical countries. Epidemiological and environmental studies pointed towards stagnant water ecosystems as potential sources of M. ulcerans, yet the ultimate reservoirs remain elusive. We hypothesized that carbon substrate determination may help elucidating the spectrum of potential reservoirs. Methodology/Principal findings In a first step, high-throughput phenotype microarray Biolog was used to profile carbon substrates in one M. marinum and five M. ulcerans strains. A total of 131/190 (69%) carbon substrates were metabolized by at least one M. ulcerans strain, including 28/190 (15%) carbon substrates metabolized by all five M. ulcerans strains of which 21 substrates were also metabolized by M. marinum. In a second step, 131 carbon substrates were investigated, through a bibliographical search, for their known environmental sources including plants, fruits and vegetables, bacteria, algae, fungi, nematodes, mollusks, mammals, insects and the inanimate environment. This analysis yielded significant association of M. ulcerans with bacteria (p = 0.000), fungi (p = 0.001), algae (p = 0.003) and mollusks (p = 0.007). In a third step, the Medline database was cross-searched for bacteria, fungi, mollusks and algae as potential sources of carbon substrates metabolized by all tested M. ulcerans; it indicated that 57% of M. ulcerans substrates were associated with bacteria, 18% with alga, 11% with mollusks and 7% with fungi. Conclusions This first report of high-throughput carbon substrate utilization by M. ulcerans would help designing media to isolate and grow this pathogen. Furthermore, the presented data suggest that potential M. ulcerans environmental reservoirs might be related to micro-habitats where bacteria, fungi, algae and mollusks are abundant. This should be followed by targeted investigations in Buruli ulcer endemic regions. PMID:28095422

  8. High-Throughput Carbon Substrate Profiling of Mycobacterium ulcerans Suggests Potential Environmental Reservoirs.

    PubMed

    Zingue, Dezemon; Bouam, Amar; Militello, Muriel; Drancourt, Michel

    2017-01-01

    Mycobacterium ulcerans is a close derivative of Mycobacterium marinum and the agent of Buruli ulcer in some tropical countries. Epidemiological and environmental studies pointed towards stagnant water ecosystems as potential sources of M. ulcerans, yet the ultimate reservoirs remain elusive. We hypothesized that carbon substrate determination may help elucidating the spectrum of potential reservoirs. In a first step, high-throughput phenotype microarray Biolog was used to profile carbon substrates in one M. marinum and five M. ulcerans strains. A total of 131/190 (69%) carbon substrates were metabolized by at least one M. ulcerans strain, including 28/190 (15%) carbon substrates metabolized by all five M. ulcerans strains of which 21 substrates were also metabolized by M. marinum. In a second step, 131 carbon substrates were investigated, through a bibliographical search, for their known environmental sources including plants, fruits and vegetables, bacteria, algae, fungi, nematodes, mollusks, mammals, insects and the inanimate environment. This analysis yielded significant association of M. ulcerans with bacteria (p = 0.000), fungi (p = 0.001), algae (p = 0.003) and mollusks (p = 0.007). In a third step, the Medline database was cross-searched for bacteria, fungi, mollusks and algae as potential sources of carbon substrates metabolized by all tested M. ulcerans; it indicated that 57% of M. ulcerans substrates were associated with bacteria, 18% with alga, 11% with mollusks and 7% with fungi. This first report of high-throughput carbon substrate utilization by M. ulcerans would help designing media to isolate and grow this pathogen. Furthermore, the presented data suggest that potential M. ulcerans environmental reservoirs might be related to micro-habitats where bacteria, fungi, algae and mollusks are abundant. This should be followed by targeted investigations in Buruli ulcer endemic regions.

  9. Oil Recovery Enhancement from Fractured, Low Permeability Reservoirs. [Carbonated Water

    DOE R&D Accomplishments Database

    Poston, S. W.

    1991-01-01

    The results of the investigative efforts for this jointly funded DOE-State of Texas research project achieved during the 1990-1991 year may be summarized as follows: Geological Characterization - Detailed maps of the development and hierarchical nature the fracture system exhibited by Austin Chalk outcrops were prepared. The results of these efforts were directly applied to the development of production decline type curves applicable to a dual-fracture-matrix flow system. Analysis of production records obtained from Austin Chalk operators illustrated the utility of these type curves to determine relative fracture/matrix contributions and extent. Well-log response in Austin Chalk wells has been shown to be a reliable indicator of organic maturity. Shear-wave splitting concepts were used to estimate fracture orientations from Vertical Seismic Profile, VSP data. Several programs were written to facilitate analysis of the data. The results of these efforts indicated fractures could be detected with VSP seismic methods. Development of the EOR Imbibition Process - Laboratory displacement as well as Magnetic Resonance Imaging, MRI and Computed Tomography, CT imaging studies have shown the carbonated water-imbibition displacement process significantly accelerates and increases recovery from oil saturated, low permeability rocks. Field Tests - Two operators amenable to conducting a carbonated water flood test on an Austin Chalk well have been identified. Feasibility studies are presently underway.

  10. Oil recovery enhancement from fractured, low permeability reservoirs. [Carbonated Water

    SciTech Connect

    Poston, S.W.

    1991-01-01

    The results of the investigative efforts for this jointly funded DOE-State of Texas research project achieved during the 1990-1991 year may be summarized as follows: Geological Characterization - Detailed maps of the development and hierarchical nature the fracture system exhibited by Austin Chalk outcrops were prepared. The results of these efforts were directly applied to the development of production decline type curves applicable to a dual-fracture-matrix flow system. Analysis of production records obtained from Austin Chalk operators illustrated the utility of these type curves to determine relative fracture/matrix contributions and extent. Well-log response in Austin Chalk wells has been shown to be a reliable indicator of organic maturity. Shear-wave splitting concepts were used to estimate fracture orientations from Vertical Seismic Profile, VSP data. Several programs were written to facilitate analysis of the data. The results of these efforts indicated fractures could be detected with VSP seismic methods.Development of the EOR Imbibition Process - Laboratory displacement as well as Magnetic Resonance Imaging, MRI and Computed Tomography, CT imaging studies have shown the carbonated water-imbibition displacement process significantly accelerates and increases recovery from oil saturated, low permeability rocks.Field Tests - Two operators amenable to conducting a carbonated water flood test on an Austin Chalk well have been identified. Feasibility studies are presently underway.

  11. Characterization of facies and permeability patterns in carbonate reservoirs based on outcrop analogs. Final report

    SciTech Connect

    Kerans, C.; Lucia, F.J.; Senger, R.K.; Fogg, G.E.; Nance, H.S.; Hovorka, S.D.

    1993-07-01

    The primary objective of this research is to develop methods for better describing the three-dimensional geometry of carbonate reservoir flow units as related to conventional or enhanced recovery of oil. San Andres and Grayburg reservoirs were selected for study because of the 13 Bbbl of remaining mobile oil and 17 Bbbl of residual oil in these reservoirs. The key data base is provided by detailed characterization of geologic facies and rock permeability in reservior-scale outcrops of the Permian San Andres Formation in the Guadalupe Mountains of New Mexico. Emphasis is placed on developing an outcrop analog for San Andres strata that can be used as (1) a guide to interpreting the regional and local geologic framework of the subsurface reservoirs (2) a data source illustrating the scales and patterns of variability of rock-fabric facies and petrophysical properties, particularly in lateral dimension, and on scales that cannot be studied during subsurface reservoir characterization. The research approach taken to achieve these objectives utilizes the integration of geologic description, geostatistical techniques, and reservoir flow simulation experiments. Results from this research show that the spatial distribution of facies relative to the waterflood direction can significantly affect how the reservoir produces. Bypassing of unswept oil occurs due to cross flow of injected water from high permeability zones into lower permeability zones were high permeability zones terminate. An area of unswept oil develops because of the slower advance of the water-injection front in the lower permeability zones. When the injection pattern is reversed, the cross-flow effect changes due to the different arrangements of rock-fabric flow units relative to the flow of injected water, and the sweep efficiency is significantly different. Flow across low-permeability mudstones occurs showing that these layers do not necessarily represent flow barriers.

  12. Carbon capture and storage reservoir properties from poroelastic inversion: A numerical evaluation

    NASA Astrophysics Data System (ADS)

    Lepore, Simone; Ghose, Ranajit

    2015-11-01

    We investigate the prospect of estimating carbon capture and storage (CCS) reservoir properties from P-wave intrinsic attenuation and velocity dispersion. Numerical analogues for two CCS reservoirs are examined: the Utsira saline formation at Sleipner (Norway) and the coal-bed methane basin at Atzbach-Schwanestadt (Austria). P-wave intrinsic dispersion curves in the field-seismic frequency band, obtained from theoretical studies based on simulation of oscillatory compressibility and shear tests upon representative rock samples, are considered as observed data. We carry out forward modelling using poroelasticity theories, making use of previously established empirical relations, pertinent to CCS reservoirs, to link pressure, temperature and CO2 saturation to other properties. To derive the reservoir properties, poroelastic inversions are performed through a global multiparameter optimization using simulated annealing. We find that the combination of attenuation and velocity dispersion in the error function helps significantly in eliminating the local minima and obtaining a stable result in inversion. This is because of the presence of convexity in the solution space when an integrated error function is minimized, which is governed by the underlying physics. The results show that, even in the presence of fairly large model discrepancies, the inversion provides reliable values for the reservoir properties, with the error being less than 10% for most of them. The estimated values of velocity and attenuation and their sensitivity to effective stress and CO2 saturation generally agree with the earlier experimental observation. Although developed and tested for numerical analogues of CCS reservoirs, the approach presented here can be adapted in order to predict key properties in a fluid-bearing porous reservoir, in general.

  13. Compaction controls on porosity in Thamama Group. Carbonate reservoirs in Abu Dhabi, U. A. E

    SciTech Connect

    Oswald, E.J.; Goff, D.F. Mueller, H.W.

    1996-01-01

    Thamama Gp. carbonate reservoirs display a pronounced decrease in porosity and reservoir thickness moving away from the crests of producing anticlines. Chemical compaction is the major process by which reservoir quality has been degraded, reducing porosities from 25% in crestal areas to 10% off structure. Lateral variations in reservoir quality are largely controlled by stylolite frequency and intensity, with no significant accompanying variations in depositional facies. This relationship can be accounted for with a [open quotes]closed-system[close quotes] chemical compaction model wherein all material dissolved at the stylolite is locally reprecipitated adjacent to stylolites. Porosity and reservoir thickness exhibit a non-linear decrease when plotted against subsea depth. The marked discontinuity of these plots suggests that differences in pore fluids during burial controlled the degree of chemical compaction, with stylolites preferentially forming in the water leg and inhibited in the oil leg. This discontinuity is more pronounced when subsea sections are re-datummed on the Halul Fm., and is interpreted to reflect a Santoniam-age [open quotes]paleo[close quote] oil-water contact during the major period of chemical compaction. Re-datumming seismic lines to reflect this Santonian structure demonstrates that stylolite-degraded porosity in the oil leg of the northern part of the field was actually in the water leg during compaction, and was only moved into the oil leg by later southward tilting of the reservoirs during the Campanian. Migration of hydrocarbons prior to stylolitization is consistent with calculated thermal histories for the field, and suggests the bulk of stylolitization commenced after 2000 ft of burial at temperatures of approximately 150[degrees]F. Delineating the [open quotes]paleo[close quotes] OWC allows for improved prediction of porosity and permeability. and accounts for almost all of the observed variation in reservoir quality.

  14. Compaction controls on porosity in Thamama Group. Carbonate reservoirs in Abu Dhabi, U.A.E.

    SciTech Connect

    Oswald, E.J.; Goff, D.F. Mueller, H.W.

    1996-12-31

    Thamama Gp. carbonate reservoirs display a pronounced decrease in porosity and reservoir thickness moving away from the crests of producing anticlines. Chemical compaction is the major process by which reservoir quality has been degraded, reducing porosities from 25% in crestal areas to 10% off structure. Lateral variations in reservoir quality are largely controlled by stylolite frequency and intensity, with no significant accompanying variations in depositional facies. This relationship can be accounted for with a {open_quotes}closed-system{close_quotes} chemical compaction model wherein all material dissolved at the stylolite is locally reprecipitated adjacent to stylolites. Porosity and reservoir thickness exhibit a non-linear decrease when plotted against subsea depth. The marked discontinuity of these plots suggests that differences in pore fluids during burial controlled the degree of chemical compaction, with stylolites preferentially forming in the water leg and inhibited in the oil leg. This discontinuity is more pronounced when subsea sections are re-datummed on the Halul Fm., and is interpreted to reflect a Santoniam-age {open_quotes}paleo{close_quote} oil-water contact during the major period of chemical compaction. Re-datumming seismic lines to reflect this Santonian structure demonstrates that stylolite-degraded porosity in the oil leg of the northern part of the field was actually in the water leg during compaction, and was only moved into the oil leg by later southward tilting of the reservoirs during the Campanian. Migration of hydrocarbons prior to stylolitization is consistent with calculated thermal histories for the field, and suggests the bulk of stylolitization commenced after 2000 ft of burial at temperatures of approximately 150{degrees}F. Delineating the {open_quotes}paleo{close_quotes} OWC allows for improved prediction of porosity and permeability. and accounts for almost all of the observed variation in reservoir quality.

  15. Recognition and significance of parasequences and parasequence sets in Leonard carbonate reservoirs, west Texas

    SciTech Connect

    Ruppel, S.C. )

    1991-03-01

    Although hydrocarbon production from reservoirs of Leonardian age is sizable (cumulative production from the Leonardian on the Central Basin Platform (CBP) alone totals 1.4 billion bbls), recovery efficiencies from these restricted, shallow-water platform carbonate deposits are among the lowest in west Texas, averaging only about 19%. Detailed examination of the Leonard section in the Dollarhide and Monahans fields on the CBP indicates that poor recovery from these reservoirs is a function of extreme vertical heterogeneity produced by high-order oscillations of relative sea level. The Leonard sequence is composed of thin (1- to 2-m thick), upward-shallowing parasequences, each of which is marked at its base by a prominent marine flooding surface. Parasequences are, in turn, packaged into 15- to 20-m parasequence set defined by variations in parasequence facies stacking patterns. Reservoir porosity is typically preferentially developed in very thin (less than 1 m) zones of grain-rich subtidal facies within parasequences, although porosity may also be encountered in capping tidal-flat deposits. Because these facies display distinct pore and permeability characteristics, with subtidal facies usually exhibiting the highest permeabilities, development of accurate reservoir models for simulation and exploitation depends on the ability to distinguish and map these deposits. Recognition and correlation of parasequences and parasequence stacking patterns in parasequence sets provide a powerful tool for more accurate mapping of facies and attendant porosity development and facilitate development of improved models necessary for efficient exploitation of these highly heterogeneous reservoirs.

  16. Modelling the effect of wettability distributions on oil recovery from microporous carbonate reservoirs

    NASA Astrophysics Data System (ADS)

    Kallel, W.; van Dijke, M. I. J.; Sorbie, K. S.; Wood, R.; Jiang, Z.; Harland, S.

    2016-09-01

    Carbonate-hosted hydrocarbon reservoirs are known to be weakly- to moderately oil-wet, but the pore-scale wettability distribution is poorly understood. Moreover, micropores, which often dominate in carbonate reservoirs, are usually assumed to be water-wet and their role in multi-phase flow is neglected. Modelling the wettability of carbonates using pore network models is challenging, because of our inability to attribute appropriate chemical characteristics to the pore surfaces and over-simplification of the pore shapes. Here, we implement a qualitatively plausible wettability alteration scenario in a two-phase flow network model that captures a diversity of pore shapes. The model qualitatively reproduces patterns of wettability alteration recently observed in microporous carbonates via high-resolution imaging. To assess the combined importance of pore-space structure and wettability on petrophysical properties, we consider a homogeneous Berea sandstone network and a heterogeneous microporous carbonate network, whose disconnected coarse-scale pores are connected through a sub-network of fine-scale pores. Results demonstrate that wettability effects are significantly more profound in the carbonate network, as the wettability state of the micropores controls the oil recovery.

  17. Carbon dioxide-water clathrate as a reservoir of CO2 on Mars

    NASA Technical Reports Server (NTRS)

    Dobrovolskis, A.; Ingersell, A. P.

    1975-01-01

    It has been suggested that the residual polar caps of Mars contain a resorvoir of permanently frozen carbon dioxide which is controlling the atmospheric pressure. However, observational data and models of the polar heat balance suggest that the temperatures of the Martian poles are too high for solid CO2 to survive permanently. On the other hand, the icelike compound carbon dioxide-water clathrate could function as a CO2 reservoir instead of solid CO2, because it is stable at higher temperatures. This paper shows that the permanent polar caps may contain several millibars of CO2 in the form of clathrate, and discusses the implications of this permanent clathrate reservoir for the present and past atmospheric pressure on Mars.

  18. Predicting phase behavior of mixtures of reservoir fluids with carbon dioxide

    SciTech Connect

    Grigg, R.B.; Lingane, P.J.

    1983-01-01

    The use of an equation of state to predict phase behavior during carbon dioxide flooding is well established. The characterization of the C/sub 7/ fraction and the selection of interaction parameters are the most important variables. Single-contact phase behavior is presented for mixtures of Ford Geraldine (Delaware), Maljamar (Grayburg), West Sussex (Shannon), and Reservoir D reservoir fluids, and of a synthetic oil with carbon dioxide. The phase behavior of these mixtures can be reproduced using 3 to 5 pseudo components and common interaction parameters. The critical properties of the pseudo components are calculated from detailed oil characterizations. Because the parameters are not further adjusted, this approach reduces the empiricism in fitting phase data and may result in a more accurate representation of the system as the composition of the oil changes during the approach to miscibility. 21 references.

  19. Carbon dioxide-water clathrate as a reservoir of CO2 on Mars

    NASA Technical Reports Server (NTRS)

    Dobrovolskis, A.; Ingersell, A. P.

    1975-01-01

    It has been suggested that the residual polar caps of Mars contain a resorvoir of permanently frozen carbon dioxide which is controlling the atmospheric pressure. However, observational data and models of the polar heat balance suggest that the temperatures of the Martian poles are too high for solid CO2 to survive permanently. On the other hand, the icelike compound carbon dioxide-water clathrate could function as a CO2 reservoir instead of solid CO2, because it is stable at higher temperatures. This paper shows that the permanent polar caps may contain several millibars of CO2 in the form of clathrate, and discusses the implications of this permanent clathrate reservoir for the present and past atmospheric pressure on Mars.

  20. Carbon storage reservoirs in watersheds support stream food webs via periphyton production.

    PubMed

    Ishikawa, Naoto F; Uchida, Masao; Shibata, Yasuyuki

    2014-05-01

    We measured the natural abundances of radiocarbon (delta14C) in macroinvertebrates, fishes, and their potential food sources, collected from the upper and lower reaches of six temperate streams in Lake Biwa basin (central Japan), three of which flow on limestone bedrock. Several carbon storage reservoirs in the watersheds show distinctive delta14C signatures (e.g., ancient carbonate rocks, -1000 per thousand; modern atmospheric CO2, +50 per thousand). Our analyses showed that the delta14C values for periphytic algae range from -361 per thousand to +21 per thousand, reflecting 14C-depleted signals from watershed storage reservoirs (carbonate rocks and/or soils). In contrast, the delta14C values for coarse particulate organic matter (CPOM) range from -6 per thousand to +62 per thousand, reflecting 14C-enriched signals from modern atmospheric CO2. The periphyton from streams on limestone bedrock was more 14C-depleted than that from streams in non-limestone areas, although the delta14C values for periphyton from the latter were less than modern atmospheric 14CO2 concentration. The delta14C values for most of the consumers were between those for periphyton and CPOM. Based on a delta14C two-source mixing models, the results suggested that the grazers rely on periphyton, while the carbon source for collectors and predators shifts from CPOM in the upper reaches of streams to periphyton in the lower reaches. The delta14C signature can trace carbon from watershed storage reservoirs to benthic production, which suggests that stream food webs are composed of mixtures of carbon originating from various sources of different ages.

  1. Integrated core-log petrofacies analysis in the construction of a reservoir geomodel: A case study of a mature Mississippian carbonate reservoir using limited data

    USGS Publications Warehouse

    Bhattacharya, S.; Doveton, J.H.; Carr, T.R.; Guy, W.R.; Gerlach, P.M.

    2005-01-01

    Small independent operators produce most of the Mississippian carbonate fields in the United States mid-continent, where a lack of integrated characterization studies precludes maximization of hydrocarbon recovery. This study uses integrative techniques to leverage extant data in an Osagian and Meramecian (Mississippian) cherty carbonate reservoir in Kansas. Available data include petrophysical logs of varying vintages, limited number of cores, and production histories from each well. A consistent set of assumptions were used to extract well-level porosity and initial saturations, from logs of different types and vintages, to build a geomodel. Lacking regularly recorded well shut-in pressures, an iterative technique, based on material balance formulations, was used to estimate average reservoir-pressure decline that matched available drillstem test data and validated log-analysis assumptions. Core plugs representing the principal reservoir petrofacies provide critical inputs for characterization and simulation studies. However, assigning plugs among multiple reservoir petrofacies is difficult in complex (carbonate) reservoirs. In a bottom-up approach, raw capillary pressure (Pc) data were plotted on the Super-Pickett plot, and log- and core-derived saturation-height distributions were reconciled to group plugs by facies, to identify core plugs representative of the principal reservoir facies, and to discriminate facies in the logged interval. Pc data from representative core plugs were used for effective pay evaluation to estimate water cut from completions, in infill and producing wells, and guide-selective perforations for economic exploitation of mature fields. The results from this study were used to drill 22 infill wells. Techniques demonstrated here can be applied in other fields and reservoirs. Copyright ?? 2005. The American Association of Petroleum Geologists. All rights reserved.

  2. Growth and activity of reservoir microorganisms under carbon capture and storage conditions

    NASA Astrophysics Data System (ADS)

    Rakoczy, Jana; Gniese, Claudia; Krüger, Martin

    2015-04-01

    Carbon capture and storage is a technology to decelerate global warming by reducing CO2 emissions into the atmosphere. To ensure safe long-term storage of CO2 in the underground a number of factors need to be considered. One of them is microbial activity in storage reservoirs, which can lead to the formation of acidic metabolites, H2S or carbonates which then might affect injectivity, permeability, pressure build-up and long-term operability. Our research focused on the effect of high CO2 concentrations on growth and activity of selected thermophilic fermenting and sulphate-reducing bacteria isolated from deep reservoirs. Experiments with supercritical carbon dioxide at 100 bar completely inhibited growth of freshly inoculated cultures and also caused a rapid decrease of growth of a pre-grown culture. This demonstrated that supercritical carbon dioxide had a certain sterilizing effect on cells. This effect was not observed in control cultures with 100 bar of hydrostatic pressure. However, when provided with a surface for attachment, CO2-inhibited cells restarted growth after CO2 release. The same was observed for organisms able to form spores. Further experiments will examine physiological and molecular properties of the model organism allowing for prediction of its sensitivity and/or adaptability to carbon dioxide in potential future storage sites.

  3. Kinetics of carbonate dissolution in CO2-saturated aqueous system at reservoir conditions

    NASA Astrophysics Data System (ADS)

    Peng, Cheng; Crawshaw, John P.; Maitland, Geoffrey; Trusler, J. P. Martin

    2014-05-01

    In recent years, carbon capture and storage (CCS) has emerged as a key technology for limiting anthropogenic CO2 emissions while allowing the continued utilisation of fossil fuels. The most promising geological storage sites are deep saline aquifers because the capacity, integrity and injection economics are most favourable, and the environmental impact can be minimal. Many rock-fluid chemical reactions are known to occur both during and after CO2 injection in saline aquifers. The importance of rock-fluid reactions in the (CO2 + H2O) system can be understood in terms of their impact on the integrity and stability of both the formation rocks and cap rocks. The chemical interactions between CO2-acidified brines and the reservoir minerals can influence the porosity and permeability of the formations, resulting in changes in the transport processes occurring during CO2 storage. Since carbonate minerals are abundant in sedimentary rocks, one of the requirements to safely implement CO2 storage in saline aquifers is to characterise the reactivity of carbonate minerals in aqueous solutions at reservoir conditions. In this work, we reported measurements of the intrinsic rate of carbonate dissolution in CO2-saturated water under high-temperature high-pressure reservoir conditions extending up to 373 K and 14 MPa. The rate of carbonate dissolution in CO2-free HCl(aq) was also measured at ambient pressure at temperatures up to 353 K. Various pure minerals and reservoir rocks were investigated in this study, including single-crystals of calcite and magnesite, and samples of dolomite, chalks and sandstones. A specially-designed batch reactor system, implementing the rotating disc technique, was used to obtain the intrinsic reaction rate at the solid/liquid interface, free of mass transfer effects. The effective area and mineralogy of the exposed surface was determined by a combination of surface characterisation techniques including XRD, SEM, EDX and optical microscopy. The

  4. Differential Effects of Legume Species on the Recovery of Soil Microbial Communities, and Carbon and Nitrogen Contents, in Abandoned Fields of the Loess Plateau, China

    NASA Astrophysics Data System (ADS)

    Li, Jin Hua; Jiao, Shu Mei; Gao, Rong Qing; Bardgett, Richard D.

    2012-12-01

    Plant-soil interactions are known to influence a wide range of ecosystem-level functions. Moreover, the recovery of these functions is of importance for the successful restoration of soils that have been degraded through intensive and/or inappropriate land use. Here, we assessed the effect of planting treatments commonly used to accelerate rates of grassland restoration, namely introduction of different legume species Medicago sativa, Astragalus adsurgens, Melilotus suaveolens, on the recovery of soil microbial communities and carbon and nitrogen contents in abandoned fields of the Loess Plateau, China. The results showed effects were species-specific, and either positive, neutral or negative depending on the measure and time-scale. All legumes increased basal respiration and metabolic quotient and had a positive effect on activity and functional diversity of the soil microbial community, measured using Biolog EcoPlate. However, soil under Astragalus adsurgens had the highest activity and functional diversity relative to the other treatments. Soil carbon and nitrogen content and microbial biomass were effectively restored in 3-5 years by introducing Medicago sativa and Astragalus adsurgens into early abandoned fields. Soil carbon and nitrogen content were retarded in 3-5 years and microbial biomass was retarded in the fifth year by introducing Melilotus suaveolens. Overall, the restoration practices of planting legumes can significantly affect soil carbon and nitrogen contents, and the biomass, activity, and functional diversity of soil microbial community. Therefore, we propose certain legume species could be used to accelerate ecological restoration of degraded soils, hence assist in the protection and preservation of the environment.

  5. Differential effects of legume species on the recovery of soil microbial communities, and carbon and nitrogen contents, in abandoned fields of the Loess Plateau, China.

    PubMed

    Li, Jin Hua; Jiao, Shu Mei; Gao, Rong Qing; Bardgett, Richard D

    2012-12-01

    Plant-soil interactions are known to influence a wide range of ecosystem-level functions. Moreover, the recovery of these functions is of importance for the successful restoration of soils that have been degraded through intensive and/or inappropriate land use. Here, we assessed the effect of planting treatments commonly used to accelerate rates of grassland restoration, namely introduction of different legume species Medicago sativa, Astragalus adsurgens, Melilotus suaveolens, on the recovery of soil microbial communities and carbon and nitrogen contents in abandoned fields of the Loess Plateau, China. The results showed effects were species-specific, and either positive, neutral or negative depending on the measure and time-scale. All legumes increased basal respiration and metabolic quotient and had a positive effect on activity and functional diversity of the soil microbial community, measured using Biolog EcoPlate. However, soil under Astragalus adsurgens had the highest activity and functional diversity relative to the other treatments. Soil carbon and nitrogen content and microbial biomass were effectively restored in 3-5 years by introducing Medicago sativa and Astragalus adsurgens into early abandoned fields. Soil carbon and nitrogen content were retarded in 3-5 years and microbial biomass was retarded in the fifth year by introducing Melilotus suaveolens. Overall, the restoration practices of planting legumes can significantly affect soil carbon and nitrogen contents, and the biomass, activity, and functional diversity of soil microbial community. Therefore, we propose certain legume species could be used to accelerate ecological restoration of degraded soils, hence assist in the protection and preservation of the environment.

  6. Thermal regime of the deep carbonate reservoir of the Po Plain (Italy)

    NASA Astrophysics Data System (ADS)

    Pasquale, V.; Chiozzi, P.; Verdoya, M.

    2012-04-01

    Italy is one of the most important countries in the world with regard to high-medium enthalpy geothermal resources, a large part of which is already extracted at relatively low cost. High temperatures at shallow to medium depth occur within a wide belt, several hundred kilometre long, west of the Apennines mountain chain. This belt, affected by recent lithosphere extension, includes several geothermal fields, which are largely exploited for electricity generation. Between the Alps and Apennines ranges, the deeper aquifer, occurring in carbonate rocks of the Po Plain, can host medium enthalpy fluids, which are exploited for district heating. Such a general picture of the available geothermal resources has been well established through several geophysical investigations and drillings. Nevertheless, additional studies are necessary to evaluate future developments, especially with reference to the deep carbonate aquifer of the Po Plain. In this paper, we focus on the eastern sector of the plain and try to gain a better understanding of the thermal regime by using synergically geothermal methodologies and geological information. The analysis of the temperatures recorded to about 6 km depth in hydrocarbon wells supplies basic constraints to outline the thermal regime of the sedimentary basin and to investigate the occurrence and importance of hydrothermal processes in the carbonate layer. After correction for drilling disturbance, temperatures were analysed, together with geological information, through an inversion technique based on a laterally constant thermal gradient model. The inferred thermal gradient changes with depth; it is quite low within the carbonate layer, while is larger in the overlying, practically impermeable formations. As the thermal conductivity variation does not justify such a thermal gradient difference, the vertical change can be interpreted as due to convective processes occurring in the carbonate layer, acting as thermal reservoir. The

  7. [Preliminary research on the feature of dissolved inorganic carbon in Wulixia Reservoir in summer, Guangxi, China].

    PubMed

    Liu, Wen; Pu, Jun-Bing; Yu, Shi; Zhang, Cheng; Au, Yik-Yu; Yuan, Dao-Xian; Yang, Hui; Tang, Wei

    2014-08-01

    To gain more knowledge on the transformation process of dissolved inorganic carbon in a karst reservoir, in situ monitoring, sampling and lab experiments of water columns were carried out at various sampling sites along the flow line in Wulixia Reservoir, Guangxi, China during early July, 2013. Results showed that: (1) The hydrochemical characteristics of study areas were controlled by the carbonate equilibrium system and the hydrochemical type of all water samples was HCO3-Ca + Mg. (2) The DIC concentration decreased gradually (DIC(Average) : from 1.03 to 0.78 mmol x L(-1)) and the delta13C(DIC) increased gradually (delta13C(DIC(Average) : from -10.21per thousand to -6.62 per thousand) from the reservoir end area to dam area. Meanwhile, with the depth increase in water column, the DIC concentration increased gradually (DIC(Average) : from 0.86 to 1.05 mmol x L(-1)) and the delta13C(DIC) decreased gradually (delta13C(DIC(Average) : from -7.88 per thousand to -13.39 per thousand) from the surface to the bottom of the reservoir. Possible reasons for these research results were found as follows: (1) Dissolution-precipitation process of carbonate substance could be inhibited by other processes such as biogeochemical processes, which played little role in delta13C(DIC) variations. (2) Thermal stratification existed in the study areas which could influence the distribution of DIC and delta13C(DIC) by affecting the distribution of plankton and its orientation and strength of metabolism process, and the extent of organic matter decomposition, and so on.

  8. Dual permeability flow behavior for modeling horizontal well production in fractured-vuggy carbonate reservoirs

    NASA Astrophysics Data System (ADS)

    Guo, Jian-Chun; Nie, Ren-Shi; Jia, Yong-Lu

    2012-09-01

    SummaryFractured-vuggy carbonate reservoirs are composed of by matrix, fracture, and vug systems. This paper is the first investigation into the dual permeability flow issue for horizontal well production in a fractured-vuggy carbonate reservoir. Considering dispersed vugs in carbonate reservoirs and treating media directly connected with horizontal wellbore as the matrix and fracture systems, a test analysis model of a horizontal well was created, and triple porosity and dual permeability flow behavior were modeled. Standard log-log type curves were drawn up by numerical simulation and flow behavior characteristics were thoroughly analyzed. Numerical simulations showed that type curves are dominated by external boundary conditions as well as the permeability ratio of the fracture system to the sum of fracture and matrix systems. The parameter κ is only relevant to the dual permeability model, and if κ is one, then the dual permeability model is equivalent to the single permeability model. There are seven main flow regimes with constant rate of horizontal well production and five flow regimes with constant wellbore pressure of horizontal well production; different flow regimes have different flow behavior characteristics. Early radial flow and linear flow regimes are typical characteristics of horizontal well production; duration of early radial flow regime is usually short because formation thickness is generally less than 100 m. Derivative curves are W-shaped, which is a reflection of inter-porosity flows between matrix, fracture, and vug systems. A distorted W-shape, which could be produced in certain situations, such as one involving an erroneously low time of inter-porosity flows, would handicap the recognition of a linear flow regime. A real case application was successfully implemented, and some useful reservoir parameters (e.g., permeability and inter-porosity flow factor) were obtained from well testing interpretation.

  9. Reservoir-Condition Pore-Scale Imaging of Reaction in Carbonates using Synchrotron Fast Tomography

    NASA Astrophysics Data System (ADS)

    Menke, H. P.; Andrew, M. G.; Bijeljic, B.; Blunt, M. J.

    2015-12-01

    Carbon capture and storage in carbonate reservoirs is essential for mitigating climate change. Supercritical CO2 mixed with host brine is acidic and can dissolve the surrounding pore structure and change flow dynamics. However, the type, speed, and magnitude of the dissolution are dependent on both the reactive transport properties of the pore-fluid and the intrinsic properties of the rock. Understanding how changes in the pore structure, chemistry, and flow properties affect dissolution is vital for successful predictive modelling both on the pore-scale and for up-scaled reservoir simulations. Reaction in carbonates has been studied at the pore-scale but has never been imaged dynamically in situ. We present an experimental method whereby both lab-based benchtop instruments and 'Pink Beam' synchrotron radiation are used in X-ray microtomography to investigate pore structure changes during supercritical CO2 injection at reservoir conditions. Three types of pure limestone rock with broadly varying rock topology were imaged under the same reservoir conditions. Flow-rate and brine acidity was varied in successive experiments by half an order of magnitude to gain insight into the impact of flow, transport, and physical heterogeneity. The images were binarized and the magnitude of dissolution was identified on a voxel-by-voxel basis to extract pore-by-pore dissolution data. The impact of dissolution on flow characteristics was studied by computing the evolution of the pore-scale velocity fields with a flow solver. We found that increasing rock heterogeneity increased channelized flow [Figure 1] through preferential pathways and that higher flow rate increased total dissolution. Additionally, decreasing reaction rate lowered overall reaction rate and made axial flow less uniform. Experimentally measured reaction rates in real rocks are at least an order of magnitude lower when compared to batch experiments. We provide evidence that this can be due to transport limitations

  10. Diagenetic overprint of original depositional architecture in a shallow water carbonate reservoir, Permian Basin, Texas

    SciTech Connect

    Ruppel, S.C.; Lucia, F.J.

    1996-12-31

    Permian shallow-water carbonate reservoirs are highly heterogeneous because of complex variations in depositional facies produced by high-frequency sea level rise and fall. Accordingly, establishment of a cycle stratigraphic framework is fundamental to defining reservoir heterogeneity. Because nearly all of these reservoirs have experienced multiple episodes of dolomitization and sulfate emplacement, however, permeability is a n of diagenetic overprint. The extent to which diagenesis can affect permeability development is dramatically displayed in the Grayburg Formation (middle Permian) at South Cowden field, Weit Texas. Three scales of cyclicity contribute to original depositional facies heterogeneity in the Grayburg; high-frequency cycles, averaging 3 meters in thickness, constitute the fundamental architectural element in the main reservoir interval. Despite original depositional heterogeneity due to this cyclicity, however, permeability development is substantially the result of two diagenetic events: (1) dolomite diagenesis in vertically burrowed wackestones and packstones and (2) late alteration and removal of anhydrite. Dolomite diagenesis in vertically burrowed wackestones and packstones has produced irregular vertical zones of higher permeability in mud-dominated bases of high-frequency cycles in leeward ramp-crest highstand successions. Because dolomite diagenesis is concentrated in burrowed highstand successions, the distribution of resultant permeability trends is partly constrained by patterns of longterm accommodation and high frequency cyclicity. Anhydrite diagenesis, which is characterized by conversion to gypsum or by complete removal of sulfate, is developed along basinward margins of the field and cross cuts original depositional framework.

  11. Diagenetic overprint of original depositional architecture in a shallow water carbonate reservoir, Permian Basin, Texas

    SciTech Connect

    Ruppel, S.C.; Lucia, F.J. )

    1996-01-01

    Permian shallow-water carbonate reservoirs are highly heterogeneous because of complex variations in depositional facies produced by high-frequency sea level rise and fall. Accordingly, establishment of a cycle stratigraphic framework is fundamental to defining reservoir heterogeneity. Because nearly all of these reservoirs have experienced multiple episodes of dolomitization and sulfate emplacement, however, permeability is a n of diagenetic overprint. The extent to which diagenesis can affect permeability development is dramatically displayed in the Grayburg Formation (middle Permian) at South Cowden field, Weit Texas. Three scales of cyclicity contribute to original depositional facies heterogeneity in the Grayburg; high-frequency cycles, averaging 3 meters in thickness, constitute the fundamental architectural element in the main reservoir interval. Despite original depositional heterogeneity due to this cyclicity, however, permeability development is substantially the result of two diagenetic events: (1) dolomite diagenesis in vertically burrowed wackestones and packstones and (2) late alteration and removal of anhydrite. Dolomite diagenesis in vertically burrowed wackestones and packstones has produced irregular vertical zones of higher permeability in mud-dominated bases of high-frequency cycles in leeward ramp-crest highstand successions. Because dolomite diagenesis is concentrated in burrowed highstand successions, the distribution of resultant permeability trends is partly constrained by patterns of longterm accommodation and high frequency cyclicity. Anhydrite diagenesis, which is characterized by conversion to gypsum or by complete removal of sulfate, is developed along basinward margins of the field and cross cuts original depositional framework.

  12. Solid hydrocarbon: a migration-of-fines problem in carbonate reservoirs

    SciTech Connect

    Lomando, A.J.

    1986-05-01

    The most familiar example of a migration-of-fines problem is authigenic kaolinite, which can detach, migrate through a pore system, and bridge pore throats, thus reducing permeability. under certain conditions, a similar problem is caused by solid hydrocarbon, independent of a mode of origin, which has precipitated in carbonate pore systems. Cores from several reservoirs in the Lower Cretaceous of east Texas were used as the data base in this study. Three morphotypes of solid hydrocarbon have been identified from thin-section and scanning electron microscope observations: droplets, peanut brittle, and carpets. Droplets are small, individual, rounded particles scattered on pore walls. Peanut brittle ranges from a continuous to discontinuous thin coating with random rounded lumps that probably have droplet precursors. Carpets are thick, continuous coatings and, at the extreme, can effectively occlude whole pores. Initially, solid hydrocarbon reduces permeability without necessarily decreasing porosity significantly. Likewise, solid hydrocarbon cannot be detected directly from wireline logs. Acidizing to enhance communication to the well bore is a common completion procedure in limestone and calcareous sandstone reservoirs. In reservoirs containing solid hydrocarbon, acid etches the substrate and releases solid hydrocarbon, which migrates in the pore system and bridges pore throats. Differential well-bore pressure also may cause solid hydrocarbon to migrate. Therefore, wettability, which controls hydrocarbon adhesion to the pore walls, and the dominant morphotype are important factors in the extent of reservoir damage.

  13. Capillarity and wetting of carbon dioxide and brine during drainage in Berea sandstone at reservoir conditions

    NASA Astrophysics Data System (ADS)

    Al-Menhali, Ali; Niu, Ben; Krevor, Samuel

    2015-10-01

    The wettability of CO2-brine-rock systems will have a major impact on the management of carbon sequestration in subsurface geological formations. Recent contact angle measurement studies have reported sensitivity in wetting behavior of this system to pressure, temperature, and brine salinity. We report observations of the impact of reservoir conditions on the capillary pressure characteristic curve and relative permeability of a single Berea sandstone during drainage—CO2 displacing brine—through effects on the wetting state. Eight reservoir condition drainage capillary pressure characteristic curves were measured using CO2 and brine in a single fired Berea sandstone at pressures (5-20 MPa), temperatures (25-50°C), and ionic strengths (0-5 mol kg-1 NaCl). A ninth measurement using a N2-water system provided a benchmark for capillarity with a strongly water wet system. The capillary pressure curves from each of the tests were found to be similar to the N2-water curve when scaled by the interfacial tension. Reservoir conditions were not found to have a significant impact on the capillary strength of the CO2-brine system during drainage through a variation in the wetting state. Two steady-state relative permeability measurements with CO2 and brine and one with N2 and brine similarly show little variation between conditions, consistent with the observation that the CO2-brine-sandstone system is water wetting and multiphase flow properties invariant across a wide range of reservoir conditions.

  14. Viral Regulation of Prokaryotic Carbon Metabolism in a Hypereutrophic Freshwater Reservoir Ecosystem (Villerest, France)

    PubMed Central

    Pradeep Ram, Angia Sriram; Colombet, Jonathan; Perriere, Fanny; Thouvenot, Antoine; Sime-Ngando, Télesphore

    2016-01-01

    The current consensus concerning the viral regulation of prokaryotic carbon metabolism is less well-studied, compared to substrate availability. We explored the seasonal and vertical distribution of viruses and its relative influence on prokaryotic carbon metabolism in a hypereutrophic reservoir, Lake Villerest (France). Flow cytometry and transmission electron microscopy (TEM) analyses to determine viral abundance (VA; range = 6.1–63.5 × 107 ml-1) and viral infection rates of prokaryotes (range = 5.3–32%) respectively suggested that both the parameters varied more significantly with depths than with seasons. Prokaryotic growth efficiency (PGE, considered as a proxy of prokaryotic carbon metabolism) calculated from prokaryotic production and respiration measurements (PGE = prokaryotic production/[prokaryotic production + prokaryotic respiration] × 100) varied from 14 to 80% across seasons and depths. Viruses through selective lyses had antagonistic impacts on PGE by regulating key prokaryotic metabolic processes (i.e., production and respiration). Higher viral lysis accompanied by higher respiration rates and lower PGE in the summer (mean = 22.9 ± 10.3%) than other seasons (mean = 59.1 ± 18.6%), led to significant loss of carbon through bacterial-viral loop and shifted the reservoir system to net heterotrophy. Our data therefore suggests that the putative adverse impact of viruses on the growth efficiency of the prokaryotic community can have strong implications on nutrient flux patterns and on the overall ecosystem metabolism in anthropogenic dominated aquatic systems such as Lake Villerest. PMID:26903963

  15. Viral Regulation of Prokaryotic Carbon Metabolism in a Hypereutrophic Freshwater Reservoir Ecosystem (Villerest, France).

    PubMed

    Pradeep Ram, Angia Sriram; Colombet, Jonathan; Perriere, Fanny; Thouvenot, Antoine; Sime-Ngando, Télesphore

    2016-01-01

    The current consensus concerning the viral regulation of prokaryotic carbon metabolism is less well-studied, compared to substrate availability. We explored the seasonal and vertical distribution of viruses and its relative influence on prokaryotic carbon metabolism in a hypereutrophic reservoir, Lake Villerest (France). Flow cytometry and transmission electron microscopy (TEM) analyses to determine viral abundance (VA; range = 6.1-63.5 × 10(7) ml(-1)) and viral infection rates of prokaryotes (range = 5.3-32%) respectively suggested that both the parameters varied more significantly with depths than with seasons. Prokaryotic growth efficiency (PGE, considered as a proxy of prokaryotic carbon metabolism) calculated from prokaryotic production and respiration measurements (PGE = prokaryotic production/[prokaryotic production + prokaryotic respiration] × 100) varied from 14 to 80% across seasons and depths. Viruses through selective lyses had antagonistic impacts on PGE by regulating key prokaryotic metabolic processes (i.e., production and respiration). Higher viral lysis accompanied by higher respiration rates and lower PGE in the summer (mean = 22.9 ± 10.3%) than other seasons (mean = 59.1 ± 18.6%), led to significant loss of carbon through bacterial-viral loop and shifted the reservoir system to net heterotrophy. Our data therefore suggests that the putative adverse impact of viruses on the growth efficiency of the prokaryotic community can have strong implications on nutrient flux patterns and on the overall ecosystem metabolism in anthropogenic dominated aquatic systems such as Lake Villerest.

  16. Sequence stratigraphic setting of Upper Smackover carbonate reservoirs in southwestern Alabama

    SciTech Connect

    Tew, B.H.; Mancini, E.A.; Mink, R.M. )

    1991-03-01

    The Upper Jurassic (Oxfordian) Smackover Formation is a regionally extensive, predominantly carbonate unit that includes significant hydrocarbon reservoirs in southwestern Alabama. Regional stratigraphic and sedimentologic data indicate that the most productive of these carbonate reservoirs occur within the lower part of the progradational, regressive highstand deposits of an unconformity-bounded, type-2 depositional sequence. This sequence, designated the LZAGC-4.1 sequence, is one of three unconformity-bounded units recognized for Jurassic strata in the eastern Gulf Coastal Plain. The LZAGC-4.1 sequence includes in ascending order, a basal type-2 unconformity, shelf margin deposits, transgressive deposits, condensed section deposits and progradational, regressive highstand deposits. A type-2 unconformity overlies the sequence. The LZAGC-4.1 sequence is interpreted to have been deposited in response to a transgressive-regressive cycle of relative sea-level change in the Oxfordian. Primary reservoir quality of these highstand deposits has been enhanced by favorable diagenetic alterations, which include dissolution and dolomitization. Diagenesis is, in part, related to subaerial exposure along the sequence boundary overlying the LZAGC-4.1 sequence. Establishment of a freshwater lens during exposure resulted in meteoric diagenesis, which includes leaching of unstable allochems and cements and mixing-zone dolomitization. These effects are particularly prevalent along the basin margin and around paleotopographic highs.

  17. Dynamic Pore-scale Reservoir-condition Imaging of Reaction in Carbonates Using Synchrotron Fast Tomography.

    PubMed

    Menke, Hannah P; Andrew, Matthew G; Vila-Comamala, Joan; Rau, Christoph; Blunt, Martin J; Bijeljic, Branko

    2017-02-21

    Underground storage permanence is a major concern for carbon capture and storage. Pumping CO2 into carbonate reservoirs has the potential to dissolve geologic seals and allow CO2 to escape. However, the dissolution processes at reservoir conditions are poorly understood. Thus, time-resolved experiments are needed to observe and predict the nature and rate of dissolution at the pore scale. Synchrotron fast tomography is a method of taking high-resolution time-resolved images of complex pore structures much more quickly than traditional µ-CT. The Diamond Lightsource Pink Beam was used to dynamically image dissolution of limestone in the presence of CO2-saturated brine at reservoir conditions. 100 scans were taken at a 6.1 µm resolution over a period of 2 hours. The images were segmented and the porosity and permeability were measured using image analysis and network extraction. Porosity increased uniformly along the length of the sample; however, the rate of increase of both porosity and permeability slowed at later times.

  18. INTEGRATED OUTCROP AND SUBSURFACE STUDIES OF THE INTERWELL ENVIRONMENT OF CARBONATE RESERVOIRS: CLEAR FORK (LEONARDIAN-AGE) RESERVOIRS, WEST TEXAS AND NEW MEXICO

    SciTech Connect

    F. Jerry Lucia

    2002-01-31

    This is the final report of the project ''Integrated Outcrop and Subsurface Studies of the Interwell Environment of Carbonate Reservoirs: Clear Fork (Leonardian-Age) Reservoirs, West Texas and New Mexico'', Department of Energy contract no. DE-AC26-98BC15105 and is the third in a series of similar projects funded jointly by the U.S. Department of Energy and The University of Texas at Austin, Bureau of Economic Geology, Reservoir Characterization Research Laboratory for Carbonates. All three projects focus on the integration of outcrop and subsurface data for the purpose of developing improved methods for modeling petrophysical properties in the interwell environment. The first project, funded by contract no. DE-AC22-89BC14470, was a study of San Andres outcrops in the Algerita Escarpment, Guadalupe Mountains, Texas and New Mexico, and the Seminole San Andres reservoir, Permian Basin. This study established the basic concepts for constructing a reservoir model using sequence-stratigraphic principles and rock-fabric, petrophysical relationships. The second project, funded by contract no. DE-AC22-93BC14895, was a study of Grayburg outcrops in the Brokeoff Mountains, New Mexico, and the South Cowden Grayburg reservoir, Permian Basin. This study developed a sequence-stratigraphic succession for the Grayburg and improved methods for locating remaining hydrocarbons in carbonate ramp reservoirs. The current study is of the Clear Fork Group in Apache Canyon, Sierra Diablo Mountains, West Texas, and the South Wasson Clear Fork reservoir, Permian Basin. The focus was on scales of heterogeneity, imaging high- and low-permeability layers, and the impact of fractures on reservoir performance. In this study (1) the Clear Fork cycle stratigraphy is defined, (2) important scales of petrophysical variability are confirmed, (3) a unique rock-fabric, petrophysical relationship is defined, (4) a porosity method for correlating high-frequency cycles and defining rock-fabric flow layers

  19. CO2 Huff-n-Puff Process in a Light Oil Shallow Shelf Carbonate Reservoir

    SciTech Connect

    Boomer, R.J.; Cole, R.; Kovar, M.; Prieditis, J.; Vogt, J.; Wehner, S.

    1999-02-24

    The application cyclic CO2, often referred to as the CO2 Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO2 Huff-n-Puff process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in capital-intensive miscible projects. Texaco Exploration and Production Inc. and the US Department of Energy have teamed up in a attempt to develop the CO2 Huff-n-Puff process in the Grayburg and San Andres formations which are light oil, shallow shelf carbonate reservoirs that exist throughout the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir.

  20. Karst-controlled reservoir heterogeneity in Ellenburger group carbonates of west Texas: Discussion

    SciTech Connect

    Mazzullo, S.J. )

    1990-07-01

    A discussion is presented on a paper by Charles Kerans (AAPG Bull. 1988). The paper dealt with karst-associated porosity and hydrocarbon reservoir heterogenity in Ellengurger (Lower Ordovician) carbonates in the Permian basin of west Texas. The purpose of this paper is not to dispute the model presented by Kerans, but instead to present some alternative models of reservoir occurrence that are not considered in his paper and that are also widely applicable to the Ellenburger and correlative strata in the Mid-Continent. The discussion is based on regional lithostratigraphy and subsurface mapping studies of the Ellenburger in the southern Midland basin, specifically in Irion, Reagan, Crockett, Schleicher, and Sterling counties (Texas).

  1. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    SciTech Connect

    T. Scott Hickman; James J. Justice

    2001-06-16

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO{sub 2}) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents.

  2. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    SciTech Connect

    T. Scott Hickman

    2003-01-17

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO{sub 2}) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents.

  3. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    SciTech Connect

    T. Scott Hickman; James J. Justice

    2001-12-11

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO{sub 2}) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents.

  4. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    SciTech Connect

    T. Scott Hickman; James J. Justice

    2001-08-10

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO{sub 2}) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents.

  5. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    SciTech Connect

    Raj Kumar; Keith Brown; T. Scott Hickman; James J. Justice

    2000-04-27

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO{sub 2}) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents.

  6. Geochemical modeling of scale formation, and formation damage during production from sulfate and carbonate mineral-bearing reservoirs

    SciTech Connect

    Macgowan, D.B.; Dunn, T.L.; Surdam, R.C. )

    1991-03-01

    The physical and chemical processes that affect reservoir fluids during production can be modeled by methodologies similar to those used for modeling clastic diagenesis. That these processes may result in formation damage and scale formation make them of interest to production geologists and engineers. Pathway modeling, based upon a series of critical divides, predicts which reactions are likely to occur between formation, production tubing, and reservoir fluids. Thermodynamic equilibria modeling calculates direction and magnitude of possible reactions. Integration of these approaches with observations of patterns of scale formation, production line, and formation damage yield a model capable of predicting the magnitude and direction of reactions that may produce negative impacts on reservoir production. Critical divides characterizing these processes in carbonate and sulfate mineral-bearing reservoirs include: (1) presence or absence of sulfate-bearing minerals within the production volume; (2) presence of iron within production line or formation; (3) ratio of concentration of bicarbonate to hydrogen sulfide; (4) capacity of aqueous and solid phases to buffer formation fluid pH; and (5) magnitude of pressure and temperature drops during production. The model qualitatively predicts: (1) likelihood of sulfide, sulfate, or carbonate mineral precipitation during production; (2) souring of the reservoir; and (3) corrosion of production tubing. The model has been developed from production histories for Weber Sandstone reservoirs, Colorado and Wyoming, and has been applied to examples of reservoir production from Tensleep and Minnelusa reservoirs in Wyoming.

  7. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. Quarterly technical progress report, October--December 1996

    SciTech Connect

    Wehner, S.; Prieditis, J.

    1996-12-31

    The principal objective of the Central Vacuum Unit (CVU) CO{sub 2} Huff-n-Puff (H-n-P) project is to determine the feasibility and practicality of the technology in a waterflooded shallow shelf carbonate environment. The results of parametric simulation of the CO{sub 2} H-n-P process, coupled with the CVU reservoir characterization components will be used to determine if this process is technically and economically feasible for field implementation. The technology transfer objective of the project is to disseminate the knowledge gained through an innovative plan in support of the Department of energy`s (DOE) objective of increasing domestic oil production and deferring the abandonment of shallow shelf carbonate reservoirs. Texaco Exploration and Production Inc`s. (TEPI) mid-term plans are to implement a full-scale miscible CO{sub 2} project in the CVU. TEPI concluded all of the tasks associated with the First Budget Period by October, 1995. The DOE approved the TEPI continuation application. Budget Period No. 2 is in progress. Initial injection of CO{sub 2} began in November, and after a short shut-in period for the soak, the well was returned to production in late December, 1995. This report, covers TEPI`s efforts at history matching the results of the field demonstration. Costs and economics of the work are presented. The majority of effort during the fourth quarter has revolved around the selection of a new project site and refinement of the demonstration design and well selection.

  8. A light carbon reservoir recorded in zircon-hosted diamond from the Jack Hills.

    PubMed

    Nemchin, Alexander A; Whitehouse, Martin J; Menneken, Martina; Geisler, Thorsten; Pidgeon, Robert T; Wilde, Simon A

    2008-07-03

    The recent discovery of diamond-graphite inclusions in the Earth's oldest zircon grains (formed up to 4,252 Myr ago) from the Jack Hills metasediments in Western Australia provides a unique opportunity to investigate Earth's earliest known carbon reservoir. Here we report ion microprobe analyses of the carbon isotope composition of these diamond-graphite inclusions. The observed delta(13)C(PDB) values (expressed using the PeeDee Belemnite standard) range between -5 per mil and -58 per mil with a median of -31 per mil. This extends beyond typical mantle values of around -6 per mil to values observed in metamorphic and some eclogitic diamonds that are interpreted to reflect deep subduction of low-delta(13)C(PDB) biogenic surface carbon. Low delta(13)C(PDB) values may also be produced by inorganic chemical reactions, and therefore are not unambiguous evidence for life on Earth as early as 4,250 Myr ago. Regardless, our results suggest that a low-delta(13)C(PDB) reservoir may have existed on the early Earth.

  9. Integrative analysis of a lacustrine carbonate reservoir, Kambala field, Cabinda, Angola

    SciTech Connect

    Lomando, A.J.; Griscom, M. )

    1993-09-01

    The presalt lacustrine rift basins of west Africa are the continued focus of exploration and development in this prolific petroleum province. Kambala field produces from the Barremian-Aptian lacustrine carbonates of the TOCA Formation. Source rocks are the rich lacustrine shales of the Bucomazi Formation. TOCA carbonates were deposited along major shorelines and around islands in large lake systems. Reservoir studies provide the necessary models and analogs to guide exploration and evaluation efforts. The TOCA reservoirs in Kambala field have been subdivided into two units. The lower TOCA is characterized by limestones and cherty dolomites, which range texturally from high-energy ooid and oncoid grainstones and packstones to lower energy ostracod wackestones and marls. The upper and lower TOCA are separated by a unit of middle Bucomazi shale. The upper TOCA is composed of thin beds of low-energy facies and thick porous carbonate units, which are pervasively dolomitized. Kambala field sits over a northwest-southeast-trending basement high. The field is bounded by intense faulting on the west and dips gently to the northeast. The faults on the eastern side are more widely spaced and have less throw than the ones on the west. Seismic amplitude maps on the upper TOCA show markedly higher amplitudes on the western and southern edges of the field. The high seismic amplitudes and intense faulting generally correlate with the zone of porous dolomite.

  10. The identification of multi-cave combinations in carbonate reservoirs based on sparsity constraint inverse spectral decomposition

    NASA Astrophysics Data System (ADS)

    Li, Qian; Di, Bangrang; Wei, Jianxin; Yuan, Sanyi; Si, Wenpeng

    2016-12-01

    Sparsity constraint inverse spectral decomposition (SCISD) is a time-frequency analysis method based on the convolution model, in which minimizing the l1 norm of the time-frequency spectrum of the seismic signal is adopted as a sparsity constraint term. The SCISD method has higher time-frequency resolution and more concentrated time-frequency distribution than the conventional spectral decomposition methods, such as short-time Fourier transformation (STFT), continuous-wavelet transform (CWT) and S-transform. Due to these good features, the SCISD method has gradually been used in low-frequency anomaly detection, horizon identification and random noise reduction for sandstone and shale reservoirs. However, it has not yet been used in carbonate reservoir prediction. The carbonate fractured-vuggy reservoir is the major hydrocarbon reservoir in the Halahatang area of the Tarim Basin, north-west China. If reasonable predictions for the type of multi-cave combinations are not made, it may lead to an incorrect explanation for seismic responses of the multi-cave combinations. Furthermore, it will result in large errors in reserves estimation of the carbonate reservoir. In this paper, the energy and phase spectra of the SCISD are applied to identify the multi-cave combinations in carbonate reservoirs. The examples of physical model data and real seismic data illustrate that the SCISD method can detect the combination types and the number of caves of multi-cave combinations and can provide a favourable basis for the subsequent reservoir prediction and quantitative estimation of the cave-type carbonate reservoir volume.

  11. FMS/FMI borehole imaging of carbonate gas reservoirs, Central Luconia Province, offshore Sarawak, Malaysia

    SciTech Connect

    Singh, U.; Van der Baan, D. )

    1994-07-01

    The Central Luconia Province, offshore Sarawak, is a significant gas province characterized by extensive development of late Miocene carbonate buildups. Some 200 carbonate structures have been seismically mapped of which 70 have been drilled. FMS/FMI borehole images were obtained from three appraisal wells drilled in the [open quotes]M[close quotes] cluster gas fields situated in the northwestern part of the province. The [open quotes]M[close quotes] cluster fields are currently part of an upstream gas development project to supply liquefied natural gas. Log facies recognition within these carbonate gas reservoirs is problematic due mainly to the large gas effect. This problem is being addressed by (1) application of neural network techniques and (2) using borehole imaging tools. Cores obtained from the M1, M3, and M4 gas fields were calibrated with the FMS/FMI images. Reservoir characterization was obtained at two different scales. The larger scale (i.e., 1:40 and 1:200) involved static normalized images where the vertical stacking pattern was observed based on recognition of bed boundaries. In addition, the greater vertical resolution of the FMS/FMI images allowed recognition of thin beds. For recognition of specific lithofacies, dynamically normalized images were used to highlight lithofacies-specific sedimentary features, e.g., clay seams/stylolites, vugs, and breccia zones. In general, the FMS/FMI images allowed (1) easier recognition of reservoir features, e.g., bed boundaries, and (2) distinction between lithofacies that are difficult to characterize on conventional wireline logs.

  12. Enhancing Caprock Integrity of Carbon Sequestration Reservoirs Using Colloidal Silica Gel

    NASA Astrophysics Data System (ADS)

    Roberts, S. K.; Ezzedine, S. M.; Bourcier, W.; Hunt, J. D.

    2013-12-01

    Silica gels are abundant in various subsurface applications. For example, it has been used in a) oil and gas industries as permeability reducer, b) geotechnical industry as a stabilizer and c) environmental industry as an isolator, and more recently in d) enhanced geothermal systems as a diverter agent; yet silica gels have not been evaluated for geological carbon sequestration. In the latter, several leakage pathways can compromise the integrity of the reservoir, thus the containment of the injected supercritical carbon dioxide. On one hand, interfacial dislocations around the injection well can lead leakage pathways compromising the well stability and integrity, and on the other, undetected preexisting fracture in the caprock can compromise the containment of the injected carbon dioxide. We propose to use silica gels as a sealing agent to seal fast pathways, minimize any leakages and enhance the overall integrity of the reservoir. Diverting and blocking agents currently used in the industry are often organic polymers that raise environmental concerns; whereas silicas are inorganic and environmentally friendly which underscore their suitability. In the current study we have developed a numerical model to simulate the flow mass and heat transport of silica gel in supercritical CO2 sequestration reservoirs. We illustrate the application of the model for minimizing CO2 leakages to the caprock by using the gel as sealing agent. Several 2D and 3D examples in porous and fractured network will be presented and design criteria for both applications will be discussed. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  13. The Role of the Permafrost Reservoir in the Global Carbon Budget

    NASA Astrophysics Data System (ADS)

    Zimov, S.; Davydov, S.; Zimova, G.; Davydova, A. I.; Zimov, N. S.; Chuprynin, V. I.; Molchanova, L. A.; Schuur, T.; Chapin, F. S.

    2004-12-01

    A high organic content is typical for all frozen sediments accumulated on permafrost, because these sediments are per se cryopreserved soils. The most interesting of these types of sediments is the frozen Pleistocene loess. It is the soil of the mammoth tundra-steppe. It covers about one million square kilometers of the north of Siberia. Carbon content of the soil is about 2%. Total carbon storage in the sediments is about 400 Gt. For many years, experiments and field measurements showed that the carbon is highly labile. The soils respire upon thawing at a rate of 3 to 20 mg C/kg/day. In the case of vast thawing of the sediments, CO2 emission connected with this will be comparable with anthropogenic emission. Field experiments and modeling showed that the thermal flux connected with Pleistocene soil respiration upon thawing (self-heating) may provide progressive permafrost melting. It is accepted that during the Pleistocene glaciation, carbon storage in terrestrial ecosystems was reduced to about 500 Gt (0 to 1350 Gt range) . But during that time, the permafrost zone occupied all the territory north of 40-45o N. By making an analogy with carbon content in preserved frozen sediments in Siberia and Alaska we can suppose that terrestrial carbon storage during glaciation was 1500 to 2000 Gt higher than present assessments. The value includes carbon storage in large-scale tundra-steppe biomes; in frozen loess of Europe and the southwest of Siberia; in solifluction sediments of slopes and in alluvium; in soil, loess and peat buried under glacial sheets. Thawing of permafrost and glaciers was accompanied by oxidation of the carbon and CO2 emission into the atmosphere. Data of the Pleistocene-Holocene dynamic of atmospheric CO2 and 14C corresponds to the permafrost reservoir dynamic. Budget of 13 CO2 corresponds to this dynamic only under conditions when the storage of organic carbon in the ocean during glaciation was significantly reduced.

  14. Layer definition and pressure buildup case histories in a carbonate reservoir

    SciTech Connect

    Vadgama, U.N.; Arifi, N.A.

    1981-01-01

    This paper presents case histories of pressure buildup analysis in a layered carbonate reservoir (Zella/Aswad Fields in the Socialist People's Libyan Arab Jamahiria). The productive formation consists of several dolomite and limestone layers separated by thin tight streaks. Lack of pressure communication between layers has been determined by pressure measurements in the individual layers using the Repeat Formation Tester (RFT). Results of the two-dimensional radial model simulated pressure buildup performance are compared to the actual measured pressure buildup data. 14 refs.

  15. Methane hydrate - A major reservoir of carbon in the shallow geosphere?

    USGS Publications Warehouse

    Kvenvolden, K.A.

    1988-01-01

    Methane hydrates are solids composed of rigid cages of water molecules that enclose methane. Sediment containing methane hydrates is found within specific pressure-temperature conditions that occur in regions of permafrost and beneath the sea in outer continental margins. Because methane hydrates are globally widespread and concentrate methane within the gas-hydrate structure, the potential amount of methane present in the shallow geosphere at subsurface depths of < ???2000 m is very large. However, estimates of the amount are speculative and range over about three orders of magnitude, from 2 ?? 103 to 4 ?? 106 Gt (gigatons = 1015 g) of carbon, depending on the assumptions made. The estimate I favor is ??? 1 ?? 104 Gt of carbon. The estimated amount of organic carbon in the methane-hydrate reservoir greatly exceeds that in many other reservoirs of the global carbon cycle - for example, the atmosphere (3.6 Gt); terrestrial biota (830 Gt); terrestrial soil, detritus and peat (1960 Gt); marine biota (3 Gt); and marine dissolved materials (980 Gt). In fact, the amount of carbon may exceed that in all fossil fuel deposits (5 ?? 103 Gt). Because methane hydrates contain so much methane and occur in the shallow geosphere, they are of interest as a potential resource of natural gas and as a possible source of atmospheric methane released by global warming. As a potential resource, methane hydrates pose both engineering and production problems. As a contributor to a changing global climate, destabilized methane hydrates, particularly those in shallow, nearshore regions of the Arctic Ocean, may have some effect, but this effect will probably be minimal, at least during the next 100 years. ?? 1988.

  16. A Constrained Differential Evolution Algorithm for Reservoir Management: Optimal Placement and Control of Wells for Geological Carbon Storage with Uncertainty in Reservoir Properties

    NASA Astrophysics Data System (ADS)

    Cihan, A.; Birkholzer, J. T.; Bianchi, M.

    2014-12-01

    Injection of large volume of CO2 into deep geological reservoirs for geologic carbon sequestration (GCS) is expected to cause significant pressure perturbations in subsurface. Large-scale pressure increases in injection reservoirs during GCS operations, if not controlled properly, may limit dynamic storage capacity and increase risk of environmental impacts. The high pressure may impact caprock integrity, induce fault slippage, and cause leakage of brine and/or CO2 into shallow fresh groundwater resources. Thus, monitoring and controlling pressure buildup are critically important for environmentally safe implementation of GCS projects. Extraction of native brine during GCS operations is a pressure management approach to reduce significant pressure buildup. Extracted brine can be transferred to the surface for utilization or re-injected into overlying/underlying saline aquifers. However, pumping, transportation, treatment and disposal of extracted brine can be challenging and costly. Therefore, minimizing volume of extracted brine, while maximizing CO2 storage, is an essential objective of the pressure management with brine extraction schemes. Selection of optimal well locations and extraction rates are critical for maximizing storage and minimizing brine extraction during GCS. However, placing of injection and extraction wells is not intuitive because of heterogeneity in reservoir properties and complex reservoir geometry. Efficient computerized algorithms combining reservoir models and optimization methods are needed to make proper decisions on well locations and control parameters. This study presents a global optimization methodology for pressure management during geologic CO2 sequestration. A constrained differential evolution (CDE) algorithm is introduced for solving optimization problems involving well placement and injection/extraction control. The CDE methodology is tested and applied for realistic CO2 storage scenarios with the presence of uncertainty in

  17. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity

    SciTech Connect

    Mancini, E.A.

    1990-01-01

    The objectives of this project are to augment the National Reservoir Database (TORIS database) and to increase our understanding of geologic heterogeneities that affect the recoveries of oil and gas from carbonate reservoirs in the State of Alabama and to identify those resources that are producible at moderate cost. These objectives will be achieved through detailed geological, engineering, and geostatistical characterization of typical Jurassic Smackover Formation hydrocarbon reservoirs in selected productive fields in the State of Alabama. The results of these studies will be used to develop and test mathematical models for prediction of the effects of reservoir heterogeneities in hydrocarbon production. Work to date has focused on the completion of Subtasks 1, 2, and 3. Subtask 1 included the survey and tabulation of available reservoir engineering and geological data relevant to the Smackover reservoir in southwestern Alabama. Subtask 2 comprises the geological and engineering characterization of Smackover reservoir lithofacies. This has been accomplished through detailed examination and analysis of geophysical well logs, core material, well cuttings, and well-test data from wells penetrating Smackover reservoirs in southwestern Alabama. From these data, reservoir heterogeneities, such as lateral and vertical changes in lithology, porosity, permeability, and diagenetic overprint, have been recognized and used to produce maps, cross sections, graphs, and other graphic representations to aid in interpretation of the geologic parameters that affect these reservoirs. Subtask 3 includes the geologic modeling of reservoir heterogeneities for Smackover reservoirs. This research has been based primarily on the evaluation of key geologic and engineering data from selected Smackover fields. 1 fig.

  18. From the pore scale to reservoir scale: Lithohydraulic flow unit characterization of a shallow shelf carbonate reservoir, North Robertson Unit, West Texas

    SciTech Connect

    Vessell, R.K.; Davies, D.K. )

    1996-01-01

    This paper presents the results of integrated geological-petrophysical reservoir characterization performed as part of the US Department of Energy Class II reservoir program. Petrographic image analysis, using a specially equipped SEM, allowed for the identification of 8 petrophysical rock types at the North Robertson Unit. Detailed log analysis resulted in the development of algorithms for the log-based identification of these rock types in 109 wells. Porosity was related to permeability for each Rock Type: thus permeability is determined from well log data. Evaluation of porosity, permeability, Sw and HPV distribution has allowed for the identification of 12 lithohydraulic flow units. These flow units have been mapped across the unit. The technique allows for the development of log-based reservoir models that are simulator-ready. The results of this study have application to all heterogeneous, shallow shelf carbonate reservoirs, they demonstrate that large fields can be successfully characterized using few cores and emphasize the importance of integrated geological-engineering analysis in reservoir characterization.

  19. From the pore scale to reservoir scale: Lithohydraulic flow unit characterization of a shallow shelf carbonate reservoir, North Robertson Unit, West Texas

    SciTech Connect

    Vessell, R.K.; Davies, D.K.

    1996-12-31

    This paper presents the results of integrated geological-petrophysical reservoir characterization performed as part of the US Department of Energy Class II reservoir program. Petrographic image analysis, using a specially equipped SEM, allowed for the identification of 8 petrophysical rock types at the North Robertson Unit. Detailed log analysis resulted in the development of algorithms for the log-based identification of these rock types in 109 wells. Porosity was related to permeability for each Rock Type: thus permeability is determined from well log data. Evaluation of porosity, permeability, Sw and HPV distribution has allowed for the identification of 12 lithohydraulic flow units. These flow units have been mapped across the unit. The technique allows for the development of log-based reservoir models that are simulator-ready. The results of this study have application to all heterogeneous, shallow shelf carbonate reservoirs, they demonstrate that large fields can be successfully characterized using few cores and emphasize the importance of integrated geological-engineering analysis in reservoir characterization.

  20. Role of sediments for dissolved organic carbon (DOC) in lakes and reservoirs

    NASA Astrophysics Data System (ADS)

    Dadi, Tallent; Wendt-Potthoff, Katrin; Friese, Kurt; Koschorreck, Matthias

    2016-04-01

    Increasing dissolved organic carbon (DOC) concentrations have been observed in many surface waters and the increasing trend is expected to continue in the future. This leads to higher water treatment costs to remove the DOC, and to potential formation of toxic, carcinogenic disinfection by-products like trihalomethanes. Ecological status can also be affected since DOC will alter the under water light regime. The sediment water interface is a potential hot spot of DOC turnover in aquatic systems. We investigated benthic DOC exchange for a complete year in two similar reservoirs (Hassel and Rappbode pre-dams, Germany) located in catchments with different land use patterns. We quantified seasonal DOC and other solute fluxes in both the riverine and lacustrine zones of the reservoirs by sediment incubation at in situ conditions. This allowed us to assess the effect of redox conditions and temperature on benthic matter fluxes. Redox conditions appeared to be the primary regulator of DOC exchange, with uptake of DOC under oxic conditions and release of DOC under anoxic conditions. Temperature effects were appararent by the increased DOC fluxes in summer, in the lacustrine zones. The benthic flux of DOC was closely linked to the fluxes of iron and phosphorus, suggesting that adsorption of DOC to Fe mineral surfaces was the major regulating mechanism behind the observed results. The DOC fluxes seem not to be influenced by the trophic state of the reservoirs which indicates that land use differences in the catchments have minimal effects on benthic DOC turnover.

  1. A microchip-based endothelium mimic utilizing open reservoirs for cell immobilization and integrated carbon ink microelectrodes for detection.

    PubMed

    Hulvey, Matthew K; Martin, R Scott

    2009-01-01

    This paper describes the fabrication and characterization of a microfluidic device that utilizes a reservoir-based approach for endothelial cell immobilization and integrated embedded carbon ink microelectrodes for the amperometric detection of extracellular nitric oxide (NO) release. The design utilizes a buffer channel to continuously introduce buffer or a plug of stimulant to the reservoir as well as a separate sampling channel that constantly withdraws buffer from the reservoir and over the microelectrode. A steel pin is used for both the fluidic connection to the sampling channel and to provide a quasi-reference electrode for the carbon ink microelectrode. Characterization of the device was performed using NO standards produced from a NONOate salt. Finally, NO release from a layer of immobilized endothelial cells was monitored and quantified using the system. This system holds promise as a means to electrochemically detect extracellular NO release from endothelial cells in either an array of reservoirs or concurrently with fluorescence-based intracellular NO measurements.

  2. Effects of Algal-Derived Carbon on Sediment Methane Production in a Eutrophic Ohio Reservoir

    NASA Astrophysics Data System (ADS)

    Berberich, M.; Buffam, I. D.; Beaulieu, J. J.; Hamilton, T. L.; Waldo, S.; Li, X.

    2016-12-01

    Nutrient loading is known to have adverse consequences for aquatic ecosystems, particularly in the form of algal blooms that may result. These blooms pose problems for humans and wildlife, including harmful toxin release, aquatic hypoxia and increased costs for water treatment. Another potential disservice resulting from algal blooms is the enhanced production of methane (CH4), a potent greenhouse gas, in aquatic sediments. Laboratory experiments have shown that algal biomass additions to sediment cores increase rates of CH4 production, but it is unclear whether or not this effect occurs at the ecosystem scale. The goal of this research was to explore the link between algal-derived carbon and methane production in the sediment of a eutrophic reservoir located in southwest Ohio, using a sampling design that capitalized on spatial and temporal gradients in autochthonous carbon input to sediments. Specifically, we aimed to determine if the within-reservoir gradient of sediment algal-derived organic matter and sediment CH4 production rates correlate. This was done by retrieving sediment cores from 15 sites within the reservoir along a known gradient of methane emission rates, at two separate time points in 2016: late spring before the sediments had received large amounts of algal input and mid-summer after algal blooms had been prevalent in the reservoir. Potential CH4 production rates, sediment organic matter source, and microbial community composition were characterized from each of the sites during both sampling periods. Sediment organic matter was characterized by source using a combination of C/N ratios, C and N stable isotopes, and excitation emission matrix spectroscopy (EEMs). Potential CH4 production rates were highest from sediments near the main reservoir tributary, with the four highest potential CH4 production rates corresponding to four sampling sites located near this main inlet. These high CH4 potential production rates also correspond to the highest

  3. Stratigraphic sections showing coal correlations within the lower coal zone of the Paleocene Fort Union Formation, Fillmore Ranch and Seaverson Reservoir quadrangles, Carbon County, Wyoming

    SciTech Connect

    Honey, J.G.; Hettinger, R.D.

    1989-01-01

    Stratigraphic sections showing coal correlations within the lower coal zone of the Paleocene Fort Union Formation, Fillmore Ranch and Seaverson Reservoir quadrangles, Carbon County, Wyoming are presented.

  4. Hydrothermal simulation of a fractured carbonate reservoir in southern Italy and automated detections of optimal positions for geothermal doublet installations

    NASA Astrophysics Data System (ADS)

    Niederau, Jan; Gomez, Sergio; Ebigbo, Anozie; Inversi, Barbara; Marquart, Gabriele; Scrocca, Davide

    2015-04-01

    In this work, we present the results of hydrothermal simulations for assessing the geothermal potential of a fractured carbonate reservoir in Campania (Guardia Lombardi). Local surface heat flows of up to 90 mW/m² suggest that this area is a potential medium-enthalpy geothermal reservoir. The targeted reservoir rocks are fractured shallow-water carbonates (Jurassic to Cretaceous) of the Apulia Platform. During the Apennine orogeny, those carbonates were affected by at least two tectonic phases: Thrust-related folding of the carbonate platform due to compression followed by extension which caused major normal faulting. Based on seismic interpretation, a discretized structural model is set up, comprising the reservoir unit and the overlying sedimentary cover. The model comprises an area of 42 km × 28 km and extends to a depth of about six kilometers. Results of calibrated hydrothermal reservoir simulations suggest that free convection occurs in some parts of the reservoir. For assessing optimal locations for potential hydrothermal doublet systems, a tool was developed which uses the results of the reservoir simulationsin combination with predefined constraints. Those constraints or minimum requirements consider: a) minimum temperature for operating the doublet system, b) minimum matrix permeability allowing for a pumping rate of 40 L/s, and c) social constraints (location of cities or conservation areas, where the construction of a potential geothermal energy plant would be problematic). The optimization tool ranks possible doublet system locations by evaluating an objective function for the minimum requirements. Those locations are further used to extract smaller models from the big reservoir model and simulate the operation of a hypothetical geothermal doublet system. By assessing the optimized results, an optimal location of a geothermal energy plant would produce water with a temperature of 163 °C from a depth of almost 4 km.

  5. Mobilization and Transport of Organic Compounds from Reservoir Rock and Caprock in Geological Carbon Sequestration Sites

    SciTech Connect

    Zhong, Lirong; Cantrell, Kirk J.; Mitroshkov, Alexandre V.; Shewell, Jesse L.

    2014-05-06

    Supercritical CO2 (scCO2) is an excellent solvent for organic compounds, including benzene, toluene, ethyl-benzene, and xylene (BTEX), phenols, and polycyclic aromatic hydrocarbons (PAHs). Monitoring results from geological carbon sequestration (GCS) field tests has shown that organic compounds are mobilized following CO2 injection. Such results have raised concerns regarding the potential for groundwater contamination by toxic organic compounds mobilized during GCS. Knowledge of the mobilization mechanism of organic compounds and their transport and fate in the subsurface is essential for assessing risks associated with GCS. Extraction tests using scCO2 and methylene chloride (CH2Cl2) were conducted to study the mobilization of volatile organic compounds (VOCs, including BTEX), the PAH naphthalene, and n-alkanes (n-C20 – n-C30) by scCO2 from representative reservoir rock and caprock obtained from depleted oil reservoirs and coal from an enhanced coal-bed methane recovery site. More VOCs and naphthalene were extractable by scCO2 compared to the CH2Cl2 extractions, while scCO2 extractable alkane concentrations were much lower than concentrations extractable by CH2Cl2. In addition, dry scCO2 was found to extract more VOCs than water saturated scCO2, but water saturated scCO2 mobilized more naphthalene than dry scCO2. In sand column experiments, moisture content was found to have an important influence on the transport of the organic compounds. In dry sand columns the majority of the compounds were retained in the column except benzene and toluene. In wet sand columns the mobility of the BTEX was much higher than that of naphthalene. Based upon results determined for the reservoir rock, caprock, and coal samples studied here, the risk to aquifers from contamination by organic compounds appears to be relatively low; however, further work is necessary to fully evaluate risks from depleted oil reservoirs.

  6. Reservoir uncertainty, Precambrian topography, and carbon sequestration in the Mt. Simon Sandstone, Illinois Basin

    USGS Publications Warehouse

    Leetaru, H.E.; McBride, J.H.

    2009-01-01

    Sequestration sites are evaluated by studying the local geological structure and confirming the presence of both a reservoir facies and an impermeable seal not breached by significant faulting. The Cambrian Mt. Simon Sandstone is a blanket sandstone that underlies large parts of Midwest United States and is this region's most significant carbon sequestration reservoir. An assessment of the geological structure of any Mt. Simon sequestration site must also include knowledge of the paleotopography prior to deposition. Understanding Precambrian paleotopography is critical in estimating reservoir thickness and quality. Regional outcrop and borehole mapping of the Mt. Simon in conjunction with mapping seismic reflection data can facilitate the prediction of basement highs. Any potential site must, at the minimum, have seismic reflection data, calibrated with drill-hole information, to evaluate the presence of Precambrian topography and alleviate some of the uncertainty surrounding the thickness or possible absence of the Mt. Simon at a particular sequestration site. The Mt. Simon is thought to commonly overlie Precambrian basement granitic or rhyolitic rocks. In places, at least about 549 m (1800 ft) of topographic relief on the top of the basement surface prior to Mt. Simon deposition was observed. The Mt. Simon reservoir sandstone is thin or not present where basement is topographically high, whereas the low areas can have thick Mt. Simon. The paleotopography on the basement and its correlation to Mt. Simon thickness have been observed at both outcrops and in the subsurface from the states of Illinois, Ohio, Wisconsin, and Missouri. ?? 2009. The American Association of Petroleum Geologists/Division of Environmental Geosciences. All rights reserved.

  7. The impact of reservoir conditions on the residual trapping of carbon dioxide in Berea sandstone

    NASA Astrophysics Data System (ADS)

    Niu, Ben; Al-Menhali, Ali; Krevor, Samuel C.

    2015-04-01

    The storage of carbon dioxide in deep brine-filled permeable rocks is an important tool for CO2 emissions mitigation on industrial scales. Residual trapping of CO2 through capillary forces within the pore space of the reservoir is one of the most significant mechanisms for storage security and is also a factor determining the ultimate extent of CO2 migration within the reservoir. In this study we have evaluated the impact of reservoir conditions of pressure, temperature, and brine salinity on the residual trapping characteristic curve of a fired Berea sandstone rock. The observations demonstrate that the initial-residual characteristic trapping curve is invariant across a wide range of pressure, temperature, and brine salinities and is also the same for CO2-brine systems as a N2-water system. The observations were made using a reservoir condition core-flooding laboratory that included high-precision pumps, temperature control, the ability to recirculate fluids for weeks at a time, and an X-ray CT scanner. Experimental conditions covered pressures of 5-20 MPa, temperatures of 25-50°C, and 0-5 mol/kg NaCl brine salinity. A novel coreflooding approach was developed, making use of the capillary end effect to create a large range in initial CO2 saturation (0.15-0.6) in a single coreflood. Upon subsequent flooding with CO2-equilibriated brine, the observation of residual saturation corresponded to the wide range of initial saturations before flooding resulting in a rapid construction of the initial-residual curve. For each condition we report the initial-residual curve and the resulting parameterization of the Land hysteresis models.

  8. Use of ``rock-typing`` to characterize carbonate reservoir heterogeneity. Final report

    SciTech Connect

    Ikwuakor, K.C.

    1994-03-01

    The objective of the project was to apply techniques of ``rock-typing`` and quantitative formation evaluation to borehole measurements in order to identify reservoir and non-reservoir rock-types and their properties within the ``C`` zone of the Ordovician Red River carbonates in the northeast Montana and northwest North Dakota areas of the Williston Basin. Rock-typing discriminates rock units according to their pore-size distribution. Formation evaluation estimates porosities and pore fluid saturation. Rock-types were discriminated using crossplots involving three rock-typing criteria: (1) linear relationship between bulk density and porosity, (2) linear relationship between acoustic interval transit-time and porosity, and (3) linear relationship between acoustic interval transit-time and bulk density. Each rock-type was quantitatively characterized by the slopes and intercepts established for different crossplots involving the above variables, as well as porosities and fluid saturations associated with the rock-types. All the existing production was confirmed through quantitative formation evaluation. Highly porous dolomites and anhydritic dolomites contribute most of the production, and constitute the best reservoir rock-types. The results of this study can be applied in field development and in-fill drilling. Potential targets would be areas of porosity pinchouts and those areas where highly porous zones are downdip from non-porous and tight dolomites. Such areas are abundant. In order to model reservoirs for enhanced oil recovery (EOR) operations, a more localized (e.g. field scale) study, expanded to involve other rock-typing criteria, is necessary.

  9. Controls on reservoir development in a shelf carbonate: Upper Jurassic smackover formation of Alabama

    SciTech Connect

    Kopaska-Merkel, D.C.; Mann, S.D.; Schmoker, J.W.

    1994-06-01

    Hydrocarbon reservoirs of the Upper Jurassic Smackover Formation in Alabama are predominately oolitic and pelletal dolostone. Pore systems are dominated by moldic and secondary intraparticle pores, intercrystalline pores, or mixtures of these pore types. All Smackover reservoirs in Alabama have been strongly affected by early cementation, dissolution of calcium-carbonate allochems, and dolomitization. Dolomitization of the Smackover in Alabama included penecontemporaneous, early burial, and late (deep) burial episodes. Fabric-selective dolomitization yielded reservoirs strongly influenced by both depositional fabric and diagenesis. Nonselective dolomitization yielded reservoirs with intercrystalline pore systems shaped primarily by diagenesis. Thermal exposure is inversely related to porosity, but the relationship is weak (r{sup 2} < 0.5). Fabric-selective dolostone is slightly more porous than nonselective dolostone when averaged over the entire study area (averages of 18.1% and 15.1%, respectively; p = 0.0001), but nonselective dolostone is more porous at a given level of equivalent vitrinite reflectance. Smackover fields on the north flank of the Wiggins arch are unusually porous given their level of thermal maturity, and are unusual in other ways as well. Local porosity variation was controlled by depositional fabric, early cementation, dissolution, and burial compaction and cementation. Regional permeability variation cannot be explained using existing data. Permeability is locally controlled by pore-throat size, the effects of dolomite crystal-size distribution, early cementation, fracturing, and burial compaction and cementation. Pore-throat size exhibits the strongest overall correlation with permeability (r{sup 2} = 0.54). Permeability and porosity are strongly correlated locally, but the regional correlation is weak.

  10. High Primary Production Contrasts with Intense Carbon Emission in a Eutrophic Tropical Reservoir

    PubMed Central

    Almeida, Rafael M.; Nóbrega, Gabriel N.; Junger, Pedro C.; Figueiredo, Aline V.; Andrade, Anízio S.; de Moura, Caroline G. B.; Tonetta, Denise; Oliveira, Ernandes S.; Araújo, Fabiana; Rust, Felipe; Piñeiro-Guerra, Juan M.; Mendonça, Jurandir R.; Medeiros, Leonardo R.; Pinheiro, Lorena; Miranda, Marcela; Costa, Mariana R. A.; Melo, Michaela L.; Nobre, Regina L. G.; Benevides, Thiago; Roland, Fábio; de Klein, Jeroen; Barros, Nathan O.; Mendonça, Raquel; Becker, Vanessa; Huszar, Vera L. M.; Kosten, Sarian

    2016-01-01

    Recent studies from temperate lakes indicate that eutrophic systems tend to emit less carbon dioxide (CO2) and bury more organic carbon (OC) than oligotrophic ones, rendering them CO2 sinks in some cases. However, the scarcity of data from tropical systems is critical for a complete understanding of the interplay between eutrophication and aquatic carbon (C) fluxes in warm waters. We test the hypothesis that a warm eutrophic system is a source of both CO2 and CH4 to the atmosphere, and that atmospheric emissions are larger than the burial of OC in sediments. This hypothesis was based on the following assumptions: (i) OC mineralization rates are high in warm water systems, so that water column CO2 production overrides the high C uptake by primary producers, and (ii) increasing trophic status creates favorable conditions for CH4 production. We measured water-air and sediment-water CO2 fluxes, CH4 diffusion, ebullition and oxidation, net ecosystem production (NEP) and sediment OC burial during the dry season in a eutrophic reservoir in the semiarid northeastern Brazil. The reservoir was stratified during daytime and mixed during nighttime. In spite of the high rates of primary production (4858 ± 934 mg C m-2 d-1), net heterotrophy was prevalent due to high ecosystem respiration (5209 ± 992 mg C m-2 d-1). Consequently, the reservoir was a source of atmospheric CO2 (518 ± 182 mg C m-2 d-1). In addition, the reservoir was a source of ebullitive (17 ± 10 mg C m-2 d-1) and diffusive CH4 (11 ± 6 mg C m-2 d-1). OC sedimentation was high (1162 mg C m-2 d-1), but our results suggest that the majority of it is mineralized to CO2 (722 ± 182 mg C m-2 d-1) rather than buried as OC (440 mg C m-2 d-1). Although temporally resolved data would render our findings more conclusive, our results suggest that despite being a primary production and OC burial hotspot, the tropical eutrophic system studied here was a stronger CO2 and CH4 source than a C sink, mainly because of high

  11. High Primary Production Contrasts with Intense Carbon Emission in a Eutrophic Tropical Reservoir.

    PubMed

    Almeida, Rafael M; Nóbrega, Gabriel N; Junger, Pedro C; Figueiredo, Aline V; Andrade, Anízio S; de Moura, Caroline G B; Tonetta, Denise; Oliveira, Ernandes S; Araújo, Fabiana; Rust, Felipe; Piñeiro-Guerra, Juan M; Mendonça, Jurandir R; Medeiros, Leonardo R; Pinheiro, Lorena; Miranda, Marcela; Costa, Mariana R A; Melo, Michaela L; Nobre, Regina L G; Benevides, Thiago; Roland, Fábio; de Klein, Jeroen; Barros, Nathan O; Mendonça, Raquel; Becker, Vanessa; Huszar, Vera L M; Kosten, Sarian

    2016-01-01

    Recent studies from temperate lakes indicate that eutrophic systems tend to emit less carbon dioxide (CO2) and bury more organic carbon (OC) than oligotrophic ones, rendering them CO2 sinks in some cases. However, the scarcity of data from tropical systems is critical for a complete understanding of the interplay between eutrophication and aquatic carbon (C) fluxes in warm waters. We test the hypothesis that a warm eutrophic system is a source of both CO2 and CH4 to the atmosphere, and that atmospheric emissions are larger than the burial of OC in sediments. This hypothesis was based on the following assumptions: (i) OC mineralization rates are high in warm water systems, so that water column CO2 production overrides the high C uptake by primary producers, and (ii) increasing trophic status creates favorable conditions for CH4 production. We measured water-air and sediment-water CO2 fluxes, CH4 diffusion, ebullition and oxidation, net ecosystem production (NEP) and sediment OC burial during the dry season in a eutrophic reservoir in the semiarid northeastern Brazil. The reservoir was stratified during daytime and mixed during nighttime. In spite of the high rates of primary production (4858 ± 934 mg C m(-2) d(-1)), net heterotrophy was prevalent due to high ecosystem respiration (5209 ± 992 mg C m(-2) d(-1)). Consequently, the reservoir was a source of atmospheric CO2 (518 ± 182 mg C m(-2) d(-1)). In addition, the reservoir was a source of ebullitive (17 ± 10 mg C m(-2) d(-1)) and diffusive CH4 (11 ± 6 mg C m(-2) d(-1)). OC sedimentation was high (1162 mg C m(-2) d(-1)), but our results suggest that the majority of it is mineralized to CO2 (722 ± 182 mg C m(-2) d(-1)) rather than buried as OC (440 mg C m(-2) d(-1)). Although temporally resolved data would render our findings more conclusive, our results suggest that despite being a primary production and OC burial hotspot, the tropical eutrophic system studied here was a stronger CO2 and CH4 source than a C

  12. Multicomponent geothermometry applied to a medium-low enthalpy carbonate-evaporite geothermal reservoir

    NASA Astrophysics Data System (ADS)

    Battistel, Maria; Barbieri, Maurizio; Hurwitz, Shaul; Eavans, William; Chiodini, Giovanni

    2014-05-01

    In order to improve the knowledge of the thermal state of medium to low-enthalpy thermal systems hosted in carbonate-evaporite rocks, a mineral-solution equilibrium model was compared to other theoretical geothermoters. We use the GeoT code (Spycher et al., 2014) which calculates reservoir temperatures based on a statistical evaluation of mineral saturation indices. The calculations were applied to study the medium and low enthalpy geothermal systems in the Tyrrhenian-Apennine area (central Italy). The study area is mainly characterized by Paleozoic metamorphic basement and a Mesozoic carbonate-evaporite sequence overlain by Oligocene-Mid Miocene flysch formations and Quaternary volcanic complexes associated with crustal extension in the Tyrrhenian area. A regional aquifer is hosted in the carbonate-evaporate formations, and smaller aquifers are hosted in the volcanic rocks. For reservoir temperature calculations the chemical composition of 58 springs and wells with a temperature between 22° and 65°C was taken into account. The waters are classified as Ca-HCO3 waters with low TDS, Ca-SO4 waters with high TDS and few HCO3-NaK type waters. The calculated reservoir temperatures of the medium-low enthalpy hydrothermal systems in Tyrrhenian-Apennine area range between 40 and 100°C. As expected, cation geothermometers provide unrealistic values of equilibrium temperature. Calculations based on the chalcedony geothermeter provide more realistic temperatures than the quartz geothermometers because silica solubility at temperatures <180°C is controlled by amorphous silica or chalcedony. GeoT simulation results show that all the considered mineral phases are either near saturation or oversaturated and the equilibrium temperatures range between 48° and 116°C. The statistical approach of "best clustering minerals", used in this model, solves the problems related to cation or single component geothermometers. For these cases, multicomponent geothermometry coupled with

  13. Global carbon burial in lakes, reservoirs and ponds; an alternative approach

    NASA Astrophysics Data System (ADS)

    Boyle, John; Hoffmann, Thomas

    2013-04-01

    It is widely stated that approximately 0.6 Pg of carbon are annually sequestered by lake, reservoir and pond sediments. The study from which this figure arises, Tranvik et al (2009), accepts: previously published values for natural lakes (0.03 to 0.07 Pg), rather higher than previously thought values for reservoirs (0.4 Pg C yr-1, based on 400,000 km2 at 1000 g C m-2, up from 0.16-0.20 Pg previously estimated), and and a previously omitted large contribution from "small eutrophic impoundments" (0.15 Pg yr-1, based on 75,000 km2 at 2000 g C m-2). As these estimates depend heavily on C burial data from 25 artificial water bodies in Iowa, we have undertaken a wider analysis to assess their global applicability. Reference: Tranvik, L.J., Downing, J.A., Cotner, J.B., Loiselle, S.A., Striegl, R.G., Ballatore, T.J., Dillon, P., Finlay, K., Fortino, K., Knoll, L.B., Kortelainen, P.L., Kutser, T., Larsen, S., Laurion, I., Leech, D.M., McCallister, S.L., McKnight, D.M., Melack, J.M., Overholt, E., Porter, J.A., Prairie, Y., Renwick, W.H., Roland, F., Sherman, B.S., Schindler, D.W., Sobek, S., Tremblay, A., Vanni, M.J., Verschoor, A.M., von Wachenfeldt, E. and Weyhenmeyer, G.A., 2009. Lakes and reservoirs as regulators of carbon cycling and climate. Limnology and Oceanography, 54(6): 2298-2314.

  14. Predicting phase behavior of mixtures of reservoir fluids with carbon dioxide

    SciTech Connect

    Grigg, R.B.; Lingane, P.J.

    1983-10-01

    The use of an equation of state to predict phase behavior during carbon dioxide flooding is well established. There is consensus that the characterization of the C fraction, the grouping of this fraction into ''pseudo components'', and the selection of interaction parameters are the most important variables. However, the literature is vague as to how to best select the pseudo components, especially when aiming for a few-component representation as for a field scale compositional simulation. Single-contact phase behavior is presented for mixtures of Ford Geraldine (Delaware), Maljamar (Grayburg), West Sussex (Shannon), and Reservoir D reservoir fluids, and of a synthetic oil C/C/C, with carbon dioxide. One can reproduce the phase behavior of these mixtures using 3-5 pseudo components and common interaction parameters. The critical properties of the pseudo components are calculated from detailed oil characterizations. Because the parameters are not further adjusted, this approach reduces the empiricism in fitting phase data and may result in a more accurate representation of the system as the composition of the oil changes during the approach to miscibility.

  15. Lagoa Feia Formation (Lower Cretaceous), Campos basin, offshore Brazil - Rift-Valley-Stage Lacustrine carbonate reservoirs

    SciTech Connect

    Bertani, R.; Petrobras, T.; Carozzi, A.V.

    1985-02-01

    The Lagoa Feia Formation, buried in excess of 3000 m, is the exploration frontier of the prolific Campos basin. It contains the source beds of all the basin's oil in addition to having its own potential carbonate reservoirs. The faulted margins of the basin fed a system of alluvial fans, sand flats, and mud flats. Alternating dry and rainy period regulated the size and nature of contemporaneous basinal alkaline lakes. Dry periods corresponded to contracted playa lakes with ostracod carbonates and euxinic shales; rainy periods corresponded to expanded pluvial lakes with pelecypod banks. Subaqueous intrusions of basaltic magma generated hyaloclastites with kerolitic ooids and hyalotuffs. Petrographic analysis reveals 5 diagenetic stages: (1) syndepositional alteration of lithoclasts to trioctahedral smectites; (2) early dolomitization, early silicification, and cementation by bladed-rim calcite and zeolites; (3) freshwater-vadose dissolution of bioclasts and lithoclasts, freshwater-phreatic sparite cementation, and neomorphism; (4) mixed saline-freshwater silicification; and (5) burial with compaction, late dolomitization, and partial conversion of smectites to illite. Pelecypod limestones with primary interparticle, secondary intraparticle, moldic, and moldic-enlarged porosities are the potential reservoirs. Ideal conditions for porosity generation and preservation were subaerial exposure followed by rapid lake expansion and burial.

  16. Mineral Dissolution and Precipitation due to Carbon Dioxide-Water-Rock Interactions: The Significance of Accessory Minerals in Carbonate Reservoirs (Invited)

    NASA Astrophysics Data System (ADS)

    Kaszuba, J. P.; Marcon, V.; Chopping, C.

    2013-12-01

    Accessory minerals in carbonate reservoirs, and in the caprocks that seal these reservoirs, can provide insight into multiphase fluid (CO2 + H2O)-rock interactions and the behavior of CO2 that resides in these water-rock systems. Our program integrates field data, hydrothermal experiments, and geochemical modeling to evaluate CO2-water-rock reactions and processes in a variety of carbonate reservoirs in the Rocky Mountain region of the US. These studies provide insights into a wide range of geologic environments, including natural CO2 reservoirs, geologic carbon sequestration, engineered geothermal systems, enhanced oil and gas recovery, and unconventional hydrocarbon resources. One suite of experiments evaluates the Madison Limestone on the Moxa Arch, Southwest Wyoming, a sulfur-rich natural CO2 reservoir. Mineral textures and geochemical features developed in the experiments suggest that carbonate minerals which constitute the natural reservoir will initially dissolve in response to emplacement of CO2. Euhedral, bladed anhydrite concomitantly precipitates in response to injected CO2. Analogous anhydrite is observed in drill core, suggesting that secondary anhydrite in the natural reservoir may be related to emplacement of CO2 into the Madison Limestone. Carbonate minerals ultimately re-precipitate, and anhydrite dissolves, as the rock buffers the acidity and reasserts geochemical control. Another suite of experiments emulates injection of CO2 for enhanced oil recovery in the Desert Creek Limestone (Paradox Formation), Paradox Basin, Southeast Utah. Euhedral iron oxyhydroxides (hematite) precipitate at pH 4.5 to 5 and low Eh (approximately -0.1 V) as a consequence of water-rock reaction. Injection of CO2 decreases pH to approximately 3.5 and increases Eh by approximately 0.1 V, yielding secondary mineralization of euhedral pyrite instead of iron oxyhydroxides. Carbonate minerals also dissolve and ultimately re-precipitate, as determined by experiments in the

  17. Holocene siliciclastic-carbonate facies mosaics, Northern Belize: Exploration analog to some midcontinent Pennsylvanian (Morrowan) reservoirs

    SciTech Connect

    Lowe, D.B.; Mazzullo, S.J.

    1995-09-01

    Midwinter Lagoon is a large, shallow coastal lagoon, bordered on its seaward side by a barrier, along the mainland coast of northern Belize. As much as 19 ft of Holocene sediments, deposited on karsted Tertiary limestones during the Flandrian transgression, consist of a complex mosaic of mixed siliciclastic and carbonate facies. Basal transgressive marine, intra-lagoonal facies are variously siliciclastic-rich carbonates to carbonate-rich siliciclastics, locally with layers of shoreline mangrove peat. These facies shallow-upward to either siliciclastic or carbonate-dominated sands or muds. Lagoonal facies were deposited within a broad topographic low, locally punctuated by bedrock highs, on the underlying limestone. The seaward edge of the barrier bar complex, which was deposited on a linear topographic high, consists mostly of quartz sands, whereas the lagoonal side is a mixture of quartzose and carbonate sediments (sands and muds). The barrier bar appears to have accreted southward in response to southerly longshore drift as a tidal inlet-spit complex; quartz sands are being transported into the lagoon from its seaward side. In terms of geometry, modern and buried, intra-lagoonal carbonate sands occur as lobes deposited proximal to extant and older tidal inlets. Either carbonate or siliciclastic sands variously occur as erratically distributed, anastomosing beach deposits around small mangrove islands and along the irregular mainland coast. In contrast, siliciclastic sands on the seaward side of the barrier define a narrow but areally persistent linear trend. Similar complex facies associations and geometries are typical of many Pennsylvanian (Morrowan) reservoirs in the midcontinent US.

  18. Facies analysis of an Upper Jurassic carbonate platform for geothermal reservoir characterization

    NASA Astrophysics Data System (ADS)

    von Hartmann, Hartwig; Buness, Hermann; Dussel, Michael

    2017-04-01

    The Upper Jurassic Carbonate platform in Southern Germany is an important aquifer for the production of geothermal energy. Several successful projects were realized during the last years. 3D-seismic surveying has been established as a standard method for reservoir analysis and the definition of well paths. A project funded by the federal ministry of economic affairs and energy (BMWi) started in 2015 is a milestone for an exclusively regenerative heat energy supply of Munich. A 3D-seismic survey of 170 square kilometer was acquired and a scientific program was established to analyze the facies distribution within the area (http://www.liag-hannover.de/en/fsp/ge/geoparamol.html). Targets are primarily fault zones where one expect higher flow rates than within the undisturbed carbonate sediments. However, since a dense net of geothermal plants and wells will not always find appropriate fault areas, the reservoir properties should be analyzed in more detail, e.g. changing the viewpoint to karst features and facies distribution. Actual facies interpretation concepts are based on the alternation of massif and layered carbonates. Because of successive erosion of the ancient land surfaces, the interpretation of reefs, being an important target, is often difficult. We found that seismic sequence stratigraphy can explain the distribution of seismic pattern and improves the analysis of different facies. We supported this method by applying wavelet transformation of seismic data. The splitting of the seismic signal into successive parts of different bandwidths, especially the frequency content of the seismic signal, changed by tuning or dispersion, is extracted. The combination of different frequencies reveals a partition of the platform laterally as well as vertically. A cluster analysis of the wavelet coefficients further improves this picture. The interpretation shows a division into ramp, inner platform and trough, which were shifted locally and overprinted in time by other

  19. Some open issues in the analysis of the storage and migration properties of fractured carbonate reservoirs

    NASA Astrophysics Data System (ADS)

    Agosta, Fabrizio

    2017-04-01

    Underground CO2 storage in depleted hydrocarbon reservoirs may become a common practice in the future to lower the concentration of greenhouse gases in the atmosphere. Results from the first experiments conducted in carbonate rocks, for instance the Lacq integrated CCS Pilot site, SW France, are quite exciting. All monitored parameters, such as the CO2 concentration at well sites, well pressures, cap rock integrity and environmental indicators show the long-term integrity of this type of geological reservoirs. Other positive news arise from the OXY-CFB-300 Compostilla Project, NW Spain, where most of the injected CO2 dissolved into the formation brines, suggesting the long-term security of this method. However, in both cases, the CO2- rich fluids partially dissolved the carbonate minerals during their migration through the fractured reservoir, modifying the overall pore volume and pressure regimes. These results support the growing need for a better understanding of the mechanical behavior of carbonate rocks over geological time of scales. In fact, it is well known that carbonates exhibit a variety of deformation mechanisms depending upon many intrinsic factors such as composition, texture, connected pore volume, and nature of the primary heterogeneities. Commonly, tight carbonates are prone to opening-mode and/or pressure solution deformation. The interplay between these two mechanisms likely affects the petrophysical properties of the fault damage zones, which form potential sites for CO2 storage due to their high values of both connected porosity and permeability. On the contrary, cataclastic deformation produces fault rocks that often form localized fluid barriers for cross-fault fluid flow. Nowadays, questions on the conditions of sealing/leakage of carbonate fault rocks are still open. In particular, the relative role played by bulk crushing, chipping, cementation, and pressure solution on connected porosity of carbonate fault rocks during structural

  20. Play-level distributions of estimates of recovery factors for a miscible carbon dioxide enhanced oil recovery method used in oil reservoirs in the conterminous United States

    USGS Publications Warehouse

    Attanasi, E.D.; Freeman, P.A.

    2016-03-02

    The retention factor is the percentage of injected CO2 that is naturally retained in the reservoir. Retention factors were also estimated in this study. For clastic reservoirs, 90 percent of the estimated retention factors were between 21.7 and 32.1 percent, and for carbonate reservoirs, 90 percent were between 23.7 and 38.2 percent. The respective median values were 22.9 for clastic reservoirs and 26.1 for carbonate reservoirs. Both distributions were right skewed. The recovery and retention factors that were calculated are consistent with the corresponding factors reported in the literature.

  1. Kinetics of carbonate mineral dissolution in CO2-acidified brines at storage reservoir conditions.

    PubMed

    Peng, Cheng; Anabaraonye, Benaiah U; Crawshaw, John P; Maitland, Geoffrey C; Trusler, J P Martin

    2016-10-20

    We report experimental measurements of the dissolution rate of several carbonate minerals in CO2-saturated water or brine at temperatures between 323 K and 373 K and at pressures up to 15 MPa. The dissolution kinetics of pure calcite were studied in CO2-saturated NaCl brines with molalities of up to 5 mol kg(-1). The results of these experiments were found to depend only weakly on the brine molality and to conform reasonably well with a kinetic model involving two parallel first-order reactions: one involving reactions with protons and the other involving reaction with carbonic acid. The dissolution rates of dolomite and magnesite were studied in both aqueous HCl solution and in CO2-saturated water. For these minerals, the dissolution rates could be explained by a simpler kinetic model involving only direct reaction between protons and the mineral surface. Finally, the rates of dissolution of two carbonate-reservoir analogue minerals (Ketton limestone and North-Sea chalk) in CO2-saturated water were found to follow the same kinetics as found for pure calcite. Vertical scanning interferometry was used to study the surface morphology of unreacted and reacted samples. The results of the present study may find application in reactive-flow simulations of CO2-injection into carbonate-mineral saline aquifers.

  2. Inorganic carbon loading as a primary driver of dissolved carbon dioxide concentrations in the lakes and reservoirs of the contiguous United States

    USGS Publications Warehouse

    McDonald, Cory P.; Stets, Edward; Striegl, Robert G.; Butman, David

    2013-01-01

    Accurate quantification of CO2 flux across the air-water interface and identification of the mechanisms driving CO2 concentrations in lakes and reservoirs is critical to integrating aquatic systems into large-scale carbon budgets, and to predicting the response of these systems to changes in climate or terrestrial carbon cycling. Large-scale estimates of the role of lakes and reservoirs in the carbon cycle, however, typically must rely on aggregation of spatially and temporally inconsistent data from disparate sources. We performed a spatially comprehensive analysis of CO2 concentration and air-water fluxes in lakes and reservoirs of the contiguous United States using large, consistent data sets, and modeled the relative contribution of inorganic and organic carbon loading to vertical CO2 fluxes. Approximately 70% of lakes and reservoirs are supersaturated with respect to the atmosphere during the summer (June–September). Although there is considerable interregional and intraregional variability, lakes and reservoirs represent a net source of CO2 to the atmosphere of approximately 40 Gg C d–1 during the summer. While in-lake CO2 concentrations correlate with indicators of in-lake net ecosystem productivity, virtually no relationship exists between dissolved organic carbon and pCO2,aq. Modeling suggests that hydrologic dissolved inorganic carbon supports pCO2,aq in most supersaturated systems (to the extent that 12% of supersaturated systems simultaneously exhibit positive net ecosystem productivity), and also supports primary production in most CO2-undersaturated systems. Dissolved inorganic carbon loading appears to be an important determinant of CO2concentrations and fluxes across the air-water interface in the majority of lakes and reservoirs in the contiguous United States.

  3. Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico - petrophysical characterization of the South Cowden Grayburg Reservoir, Ector County, Texas. Final report

    SciTech Connect

    Lucia, F.J.

    1997-06-01

    Reservoir performance of the South Cowden Grayburg field suggests that only 21 percent of the original oil in place has been recovered. The purpose of this study is to construct a realistic reservoir model to be used to predict the location of the remaining mobile oil. Construction of reservoir models for fluid-flow simulation of carbonate reservoirs is difficult because they typically have complicated and unpredictable permeability patterns. Much of the difficulty results from the degree to which diagenetic overprinting masks depositional textures and patterns. For example, the task of constructing a reservoir model of a limestone reservoir that has undergone only cementation and compaction is easier than constructing a model of a karsted reservoir that has undergone cavern formation and collapse as well as cementation and compaction. The Permian-age carbonate-ramp reservoirs in the Permian Basin, West Texas and New Mexico, are typically anhydritic dolomitized limestone. Because the dolomitization occurred soon after deposition, depositional fabrics and patterns are often retained, and a reservoir model can be constructed using depositional concepts. Recent studies of the San Andres outcrop in the Guadalupe Mountains and the Seminole San Andres reservoir in the Permian Basin illustrate how depositional fabrics and patterns can be used to construct a reservoir model when depositional features are retained.

  4. Characterization from borehole wall and X-ray scan images of heterogeneities in carbonate reservoirs

    NASA Astrophysics Data System (ADS)

    Hébert, V.; Pezard, P. A.; Garing, C.; Gouze, P.; Camoin, G.; Lapointe, P.

    2009-12-01

    Salt water intrusion in coastal reservoirs is highly influenced by geological and petrophysical structures. In particular, heterogeneities and anisotropy in porous media (karst, vug) control fluid transport and dispersion. To develop new strategies for the quantitative description and analysis of fluid flow and salt transport in coastal aquifers, a new experimental site was developed in SE Mallorca (Spain) in the context of the ALIANCE EC project (2002-2005). Multi-scalar quantitative and descriptive methods (from µm to m) are developed to identify and map microstructures, heterogeneities and their hydrogeological impact on the reservoir. The objective of this study is to better understand the link between geological and hydrogeological properties of heterogeneous reservoir. The Mallorcan site cuts the Miocene carbonate reef platform and is located 6 km inland, where a salt wedge transition is found from 60 to 80 m depth. The geological structure includes large multi-scale heterogeneities, often bound to lateral facies variations. This experimental site provides thus a unique laboratory to study saltwater intrusion processes and develop new downhole investigation methods. This study focuses on borehole geophysical measurements and images, and X-ray core scan images. New image analysis methods have been developed to better characterize heterogeneities in terms of size distribution, aspect ratio and porosity. Optical and acoustic borehole wall images offer a continuous insight into meso-scale porosity (such as karstic channels and megapores) from mm to 100 m scale. X-ray cores scans were obtained from a tomography scanner by TOTAL. These two methodologies from RX tomography scans and borehole wall images are compared and discussed. Petrophysical parameters were extracted from X-ray images with a dedicated 3D data analysis software. The scan images lead to the identification and quantification of the micro- and vuggy porosity. It is found that the distribution of

  5. Analytical solution of geological carbon sequestration under constant pressure injection into a horizontal radial reservoir

    NASA Astrophysics Data System (ADS)

    Jhang, R.; Liou, T.

    2013-12-01

    Carbon capture and sequestration (CCS) is believed to be an economically feasible technology to mitigate global warming by capturing carbon dioxide (CO2), the major component of greenhouse gases, from the atmosphere and injecting it into deep geological formations.Several mechanisms can help trap CO2 in the pore space of a geological reservoir, stratigraphic and structural trapping, hydrodynamic trapping, and geochemical trapping.Besides these trapping mechanisms, another important issue that deserves careful attention is the risk of CO2 leakage. The common ';constant injection rate' scenario may induce high pressure buildup that will endanger the mechanical integrity as well as the sealing capability of the cap rock. Instead of injecting CO2 at a constant mass rate, CO2 can be injected into the reservoir by fixing the pressure (usually the bottom-hole pressure) in the injection borehole. By doing so, the inevitable pressure buildup associated with the constant injection scheme can be completely eliminated in the constant pressure injection scheme. In this paper, a semi-analytical solution for CO2 injection with constant pressure was developed. For simplicity, structural and geochemical trapping mechanisms were not considered. Therefore, a horizontal reservoir with infinite radial extent was considered. Prior to injection, the reservoir is fully saturated with the formation brine. It is assumed that CO2 does not mix with brine such that a sharp interface is formed once CO2 invades the brine-saturated pores. Because of the density difference between CO2 and brine, CO2 resides above the interface. Additional assumptions were also made when building up the brine and CO2 mass balance equations: (1) both of the fluids and the geological formations are incompressible, (2) capillary pressure is neglected, (3)there is no fluid flow in the vertical direction, and the horizontal flow satisfies the Darcy's law.In order to solve for the height of brine-CO2 interface, the two

  6. Predicting the natural state of fractured carbonate reservoirs: An Andector Field, West Texas test of a 3-D RTM simulator

    SciTech Connect

    Tuncay, K.; Romer, S.; Ortoleva, P.; Hoak, T.; Sundberg, K.

    1998-12-31

    The power of the reaction, transport, mechanical (RTM) modeling approach is that it directly uses the laws of geochemistry and geophysics to extrapolate fracture and other characteristics from the borehole or surface to the reservoir interior. The objectives of this facet of the project were to refine and test the viability of the basin/reservoir forward modeling approach to address fractured reservoir in E and P problems. The study attempts to resolve the following issues: role of fracturing and timing on present day location and characteristics; clarifying the roles and interplay of flexure dynamics, changing rock rheological properties, fluid pressuring and tectonic/thermal histories on present day reservoir location and characteristics; and test the integrated RTM modeling/geological data approach on a carbonate reservoir. Sedimentary, thermal and tectonic data from Andector Field, West Texas, were used as input to the RTM basin/reservoir simulator to predict its preproduction state. The results were compared with data from producing reservoirs to test the RTM modeling approach. The effects of production on the state of the field are discussed in a companion report. The authors draw the following conclusions: RTM modeling is an important new tool in fractured reservoir E and P analysis; the strong coupling of RTM processes and the geometric and tensorial complexity of fluid flow and stresses require the type of fully coupled, 3-D RTM model for fracture analysis as pioneered in this project; flexure analysis cannot predict key aspects of fractured reservoir location and characteristics; fracture history over the lifetime of a basin is required to understand the timing of petroleum expulsion and migration and the retention properties of putative reservoirs.

  7. Integrated Sedimentological Approach to Assess Reservoir Quality and Architecture of Khuff Carbonates: Outcrop Analog, Central Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Osman, Mutsim; Abdullatif, Osman

    2017-04-01

    The Permian to Triassic Khuff carbonate reservoirs (and equivalents) in the Middle East are estimated to contain about 38.4% of the world's natural gas reserves. Excellent exposed outcrops in central Saudi Arabia provide good outcrop equivalents to subsurface Khuff reservoirs. This study conduct high resolution outcrop scale investigations on an analog reservoir for upper Khartam of Khuff Formation. The main objective is to reconstruct litho- and chemo- stratigraphic outcrop analog model that may serve to characterize reservoir high resolution (interwell) heterogeneity, continuity and architecture. Given the fact of the limitation of subsurface data and toolsin capturing interwell reservoir heterogeneity, which in turn increases the value of this study.The methods applied integrate sedimentological, stratigraphic petrographic, petrophysical data and chemical analyses for major, trace and rare earth elements. In addition, laser scanning survey (LIDAR) was also utilized in this study. The results of the stratigraphic investigations revealed that the lithofacies range from mudstone, wackestone, packestone and grainstone. These lithofacies represent environments ranging from supratidal, intertidal, subtidal and shoal complex. Several meter-scale and less high resolution sequences and composite sequences within 4th and 5th order cycles were also recognized in the outcrop analog. The lithofacies and architectural analysis revealed several vertically and laterally stacked sequences at the outcrop as revealed from the stratigraphic sections and the lidar scan. Chemostratigraphy is effective in identifying lithofacies and sequences within the outcrop analog. Moreover, different chemical signatures were also recognized and allowed establishing and correlating high resolution lithofacies, reservoir zones, layers and surfaces bounding reservoirs and non-reservoir zones at scale of meters or less. The results of this high resolution outcrop analog study might help to understand

  8. Cretaceous tide-dominated carbonate ramp: Comparison of reservoir hetergeneity in tide-versus wave-dominated carbonate ramp systems

    SciTech Connect

    Kerans, C.

    1995-08-01

    Cretaceous (upper Albian) carbonate ramp strata, Pecos River Canyon, Texas, provide a uniquely continuous exposure of a tide-dominated ramp reservoir analog. The continuous 100-km shelf-to-basin outcrop begins in inner ramp mud-rich facies that record both high-frequency (20-100 ky) and intermediate frequency (>200 ky) cyclicity. The ramp-crest is up to 40 km across depositional dip. Intermediate-scale cycles in the ramp crest include basal oyster and toucasid wackestones, chondrodontid-rudist packstones, rudist-skeletal grainstones, and caprinid biostromes. Ramp-crest grainstones are 4-23 m in thickness and extend more than 20 km in a shelf to basin direction. Rudist biostromes are 3-7 m in thickness and are up to several kilometers in dip continuity except in deeper outer ramp settings where 100-200 m wide mounds are more common. The ramp crest is dominated by grain-rich facies with moderate to high permeability. Toucasid wackestones and oyster marls are 1-5 m in thickness and extend tens of kilometers in a dip direction, representing potential fluid flow barriers. Wave-dominated ramp systems of the Permian of West Texas provide a contrast to the Cretaceous tide-dominated setting. Low-permeability high-frequency cycle base mudstones and high-permeability cycle-top grainstones are preserved in both inner ramp and ramp crest settings. Fluid-flow modeling of these Permian wave-dominated reservoir strata illustrates that the intercalation of thin high- and low-permeability layers result in crossflow trapping and thief zones controlling the position and amount of remaining oil saturation. The depositional homogeneity of the Cretaceous tide-dominated ramp indicates that diagenetic heterogeneities and gravitational effects are potentially dominant controls on reservoir performance for these strata.

  9. DESIGN AND IMPLEMENTATION OF A CO2 FLOOD UTILIZING ADVANCED RESERVOIR CHARACTERIZATION AND HORIZONTAL INJECTION WELLS IN A SHALLOW SHELF CARBONATE APPROACHING WATERFLOOD DEPLETION

    SciTech Connect

    K.J. Harpole; Ed G. Durrett; Susan Snow; J.S. Bles; Carlon Robertson; C.D. Caldwell; D.J. Harms; R.L. King; B.A. Baldwin; D. Wegener; M. Navarrette

    2002-09-01

    The purpose of this project was to economically design an optimum carbon dioxide (CO{sub 2}) flood for a mature waterflood nearing its economic abandonment. The original project utilized advanced reservoir characterization and CO{sub 2} horizontal injection wells as the primary methods to redevelop the South Cowden Unit (SCU). The development plans; project implementation and reservoir management techniques were to be transferred to the public domain to assist in preventing premature abandonment of similar fields. The Unit was a mature waterflood with water cut exceeding 95%. Oil must be mobilized through the use of a miscible or near-miscible fluid to recover significant additional reserves. Also, because the unit was relatively small, it did not have the benefit of economies of scale inherent in normal larger scale projects. Thus, new and innovative methods were required to reduce investment and operating costs. Two primary methods used to accomplish improved economics were use of reservoir characterization to restrict the flood to the higher quality rock in the unit and use of horizontal injection wells to cut investment and operating costs. The project consisted of two budget phases. Budget Phase I started in June 1994 and ended late June 1996. In this phase Reservoir Analysis, Characterization Tasks and Advanced Technology Definition Tasks were completed. Completion enabled the project to be designed, evaluated, and an Authority for Expenditure (AFE) for project implementation submitted to working interest owners for approval. Budget Phase II consisted of the implementation and execution of the project in the field. Phase II was completed in July 2001. Performance monitoring, during Phase II, by mid 1998 identified the majority of producing wells which under performed their anticipated withdrawal rates. Newly drilled and re-activated wells had lower offtake rates than originally forecasted. As a result of poor offtake, higher reservoir pressure was a concern

  10. Carbon Reservoir History of Mars Constrained by Atmospheric Isotopic Measurements and Carbonate Remote Sensing

    NASA Astrophysics Data System (ADS)

    Hu, R.; Kass, D. M.; Ehlmann, B. L.; Yung, Y. L.

    2015-12-01

    The evolution of the atmosphere on Mars is one of the most intriguing problems in the exploration of the Solar System, and the climate of Mars may have evolved from a warmer, wetter early state to the cold, dry current state. Because CO2 is the major constituent of Mars's atmosphere, its isotopic signatures offer a unique window to trace the evolution of climate on Mars. We derive new quantitative constraints on the amount of carbonate deposition and the atmospheric pressure of Mars through time, extending into the Noachian, ~3.8 Gyr before present. This determination is based on recent Mars Science Laboratory (MSL) isotopic measurements of Mars's atmosphere, recent orbiter, lander, and rover measurements of Mars's surface, and a newly identified mechanism (photodissociation of CO) that efficiently enriches the heavy carbon isotope. In particular, we find that escape via CO photodissociation on Mars has a fractionation factor of 0.6 and hence, photochemical escape processes can effectively enrich 13C in the Mars's atmosphere during the Amazonian. This enrichment is partially compensated by moderate carbonate precipitation during the late Noachian and/or Hesperian. The current atmospheric 13C/12C and rock and soil carbonate measurements indicate an early atmosphere with a surface pressure less than 1 bar. Only scenarios with large amounts of carbonate formation in open lakes permit higher values up to 1.8 bars. The evolutionary scenarios are fully testable with data from the MAVEN mission and further studies of the isotopic composition of carbonate in the Martian rock record through time.

  11. Baca geothermal demonstration project. Equation-of-state for water-carbon dioxide mixtures: implications for Baca reservoir

    SciTech Connect

    Pritchett, J.W.; Rice, M.H.; Riney, T.D.

    1981-02-01

    An equation-of-state package for water-carbon dioxide mixtures has been constructed from available thermodynamic data that covers the range of interest to the Baca reservoir system. The package has been used to examine the thermodynamic state of the Baca reservoir fluid for conditions of temperature, pressure and CO/sub 2/ content believed to bracket conditions existing at the production depth of the wells in the Redondo Creek area. It is shown that the reservoir fluid may be either all-liquid or two-phase at various well locations and depths, depending on the CO/sub 2/ content. It is also shown that the CO/sub 2/ content at reservoir conditions cannot be reliably inferred from pressure/temperature measurements made on flowing wells. The equation-of-state package has been incorporated into a general purpose geothermal reservoir simulator and a series of calculations made which show that the CO/sub 2/ content of the produced fluid may be less than or greater than that of the reservoir fluid. The characteristics of the produced fluid are sensitive to the CO/sub 2/ content in the reservoir.

  12. Design and Implementation of a CO2 Flood Utilizing Advanced Reservoir Characterization and Horizontal Injection Wells In a Shallow Shelf Carbonate Approaching Waterflood Depletion, Class II

    SciTech Connect

    Czirr, K.L.; Gaddis, M.P.; Moshell, M.K.

    2002-02-21

    The principle objective of this project is to demonstrate the economic viability and widespread applicability of an innovative reservoir management and carbon dioxide (CO2) flood project development approach for improving CO2 flood project economics in shallow shelf carbonate (SSC) reservoirs.

  13. INTEGRATED OUTCROP AND SUBSURFACE STUDIES OF THE INTERWELL ENVIRONMENT OF CARBONATE RESERVOIRS: CLEAR FORK (LEONARADIAN AGE) RESERVOIRS, WEST TEXAS AND NEW MEXICO

    SciTech Connect

    James W. Jennings, Jr.; F. Jerry Lucia

    2001-10-01

    Petrophysical heterogeneity in the South Wasson Clear Fork (SWCF) reservoir and other shallow-water platform carbonates in the Permian Basin and elsewhere is composed of a large-scale stratigraphically controlled component and a small-scale poorly correlated component. The large-scale variability exists as a flow-unit scale petrophysical layering that is laterally persistent at interwell scales and produces highly stratified reservoir behavior. Capturing the rate-enhancing effect of the small-scale variability requires carefully controlled averaging procedures at four levels of scaleup. Porosity can be easily scaled using arithmetic averaging procedures. Permeability, however, requires carefully controlled power-averaging procedures. Effective permeability is increased at every scaleup level.

  14. Seasonal patterns in carbon dioxide in 15 mid-continent (USA) reservoirs

    USGS Publications Warehouse

    Jones, John R.; Obrecht, Daniel V.; Graham, Jennifer; Balmer, Michelle B.; Filstrup, Christopher T.; Downing, John A.

    2016-01-01

    Evidence suggests that lakes are important sites for atmospheric CO2 exchange and so play a substantial role in the global carbon budget. Previous research has 2 weaknesses: (1) most data have been collected only during the open-water or summer seasons, and (2) data are concentrated principally on natural lakes in northern latitudes. Here, we report on the full annual cycle of atmospheric CO2 exchanges of 15 oligotrophic to eutrophic reservoirs in the Glacial Till Plains of the United States. With one exception, these reservoirs showed an overall loss of CO2 during the year, with most values within the lower range reported for temperate lakes. There was a strong cross-system seasonal pattern: an average of 70% of total annual CO2 efflux occurred by the end of spring mixis; some 20% of annual flux was reabsorbed during summer stratification; and the remaining 50% of efflux was lost during autumnal mixing. Net annual flux was negatively correlated with depth and positively correlated with both water residence time and DOC, with the smallest annual CO2 efflux measured in shallow fertile impoundments. Strong correlations yield relationships allowing regional up-scaling of CO2 evasion. Understanding lacustrine CO2 uptake and evasion requires seasonal analyses across the full range of lake trophic states and morphometric attributes.

  15. Experiments and modeling of variably permeable carbonate reservoir samples in contact with CO₂-acidified brines

    SciTech Connect

    Smith, Megan M.; Hao, Yue; Mason, Harris E.; Carroll, Susan A.

    2014-12-31

    Reactive experiments were performed to expose sample cores from the Arbuckle carbonate reservoir to CO₂-acidified brine under reservoir temperature and pressure conditions. The samples consisted of dolomite with varying quantities of calcite and silica/chert. The timescales of monitored pressure decline across each sample in response to CO₂ exposure, as well as the amount of and nature of dissolution features, varied widely among these three experiments. For all samples cores, the experimentally measured initial permeability was at least one order of magnitude or more lower than the values estimated from downhole methods. Nondestructive X-ray computed tomography (XRCT) imaging revealed dissolution features including “wormholes,” removal of fracture-filling crystals, and widening of pre-existing pore spaces. In the injection zone sample, multiple fractures may have contributed to the high initial permeability of this core and restricted the distribution of CO₂-induced mineral dissolution. In contrast, the pre-existing porosity of the baffle zone sample was much lower and less connected, leading to a lower initial permeability and contributing to the development of a single dissolution channel. While calcite may make up only a small percentage of the overall sample composition, its location and the effects of its dissolution have an outsized effect on permeability responses to CO₂ exposure. The XRCT data presented here are informative for building the model domain for numerical simulations of these experiments but require calibration by higher resolution means to confidently evaluate different porosity-permeability relationships.

  16. Geostatistical reservoir characterization of complex lateral and vertical sequences in a mixed carbonate platform

    SciTech Connect

    Norris, R.J.; Alabert, F.G.; Massonnat, G.J. )

    1994-07-01

    In recent years reservoir characterization through the use of geostatistics has become an almost routine part of production geology. Many techniques are available within the broad title of geostatistics, having been developed in response to many types of problem. One characteristic feature of almost all techniques (Stochastic Indicator Simulation, Boolean [open quotes]object[close quotes] Modeling, Gaussian [and Truncated Gaussian] methods and Optimized Markov-fields) is their reliance on the concept of quantifiable correlations, which reflect some aspect of the shape of [open quotes]objects.[close quotes] For example, almost any of the above noted techniques, and their variants, could be used to model fluvial, deltaic, or turbiditic reservoirs because in each case facies can be described in terms of geometries (channels, lobes, etc.). This study considers the complex lateral and vertical variations of a mixed carbonate platform environment, where facies cannot be easily characterized by simple geometries. The complex heterogeneities are a function of changes in sea level, representing fluctuations over several orders of cyclicity. Given facies have no characteristic form, being the product of the interplay between sediment supply and sea level change. This type of environment is, therefore, characterized by a good deal of information concerning trends in the data, while correlations and geometries are almost meaningless. Associated with the concepts of cyclicity, rules concerning the reappearance of facies, or otherwise, were developed. For example, minor recurrences of maximum flooding surfaces could be tolerated within individual units but other specified recurrences need to be excluded.

  17. Carbon dioxide-brine-rock interactions in a carbonate reservoir capped by shale: Experimental insights regarding the evolution of trace metals

    NASA Astrophysics Data System (ADS)

    Marcon, Virginia; Kaszuba, John P.

    2015-11-01

    Trace metal behavior provides important information regarding fluid-rock interactions in CO2-charged water-rock systems and constrains potential environmental impacts. Hydrothermal experiments evaluated mechanisms of release, evolution, and subsequent scavenging of trace metals at 160 °C and 25 MPa. Experiments were designed to simulate two theoretical locations within a CO2-charged reservoir: (1) at the contact between a shale caprock and carbonate reservoir and (2) deeper within a carbonate reservoir, away from the shale. CO2 injection into brine (ionic strength = 3.3 mol/kg) decreased the pH by 1-2 units; concomitant mineral dissolution elevated Ba, Co, Cu, Pb, and V concentrations in the brine at both simulated locations within the reservoir. Additionally, Fe, Ni, and Zn concentrations increased in the mixed shale-carbonate experiment; Ba and Cd concentrations increased in the carbonate-only experiment. However, concentrations of Fe, Ba, Cr, and Pb in the mixed shale-carbonate experiment and Cr, Pb, V, and Zn within the carbonate-only experiment subsequently decreased as a result of precipitation of sulfides (Fe and Co sulfides), oxides, and clays. At the conclusion of the experiments, Fe, Pb, and Cr exceeded U.S. Environmental Protection Agency maximum contaminant limits in both experiments. In addition, zinc exceeded the limits at the simulated shale-carbonate contact and Ba, Cu, and Cd exceeded the limits in the simulated carbonate reservoir. Experimentally observed trends of decreasing Fe and Pb concentrations suggest these trace metals become less of an environmental concern as CO2-water-rock reactions evolve with time. The shale caprock plays an active role in trace metal evolution. The shale is a large source of metals, but also provides metal sinks such as primary clays, secondary smectites, and other silicates that are not found deeper within the carbonate reservoir, away from the shale. This potential mechanism of self-healing mitigates, but does not

  18. Organic carbon burial in lakes and reservoirs of the conterminous United States

    USGS Publications Warehouse

    Clow, David W.; Stackpoole, Sarah M.; Verdin, Kristine L.; Butman, David E.; Zhu, Zhi-Liang; Krabbenhoft, David P.; Striegl, Robert G.

    2015-01-01

    Organic carbon (OC) burial in lacustrine sediments represents an important sink in the global carbon cycle; however, large-scale OC burial rates are poorly constrained, primarily because of the sparseness of available data sets. Here we present an analysis of OC burial rates in water bodies of the conterminous U.S. (CONUS) that takes advantage of recently developed national-scale data sets on reservoir sedimentation rates, sediment OC concentrations, lake OC burial rates, and water body distributions. We relate these data to basin characteristics and land use in a geostatistical analysis to develop an empirical model of OC burial in water bodies of the CONUS. Our results indicate that CONUS water bodies sequester 20.8 (95% CI: 9.4–65.8) Tg C yr–1, and spatial patterns in OC burial are strongly influenced by water body type, size, and abundance; land use; and soil and vegetation characteristics in surrounding areas. Carbon burial is greatest in the central and southeastern regions of the CONUS, where cultivation and an abundance of small water bodies enhance accumulation of sediment and OC in aquatic environments.

  19. Organic Carbon Burial in Lakes and Reservoirs of the Conterminous United States.

    PubMed

    Clow, David W; Stackpoole, Sarah M; Verdin, Kristine L; Butman, David E; Zhu, Zhiliang; Krabbenhoft, David P; Striegl, Robert G

    2015-07-07

    Organic carbon (OC) burial in lacustrine sediments represents an important sink in the global carbon cycle; however, large-scale OC burial rates are poorly constrained, primarily because of the sparseness of available data sets. Here we present an analysis of OC burial rates in water bodies of the conterminous U.S. (CONUS) that takes advantage of recently developed national-scale data sets on reservoir sedimentation rates, sediment OC concentrations, lake OC burial rates, and water body distributions. We relate these data to basin characteristics and land use in a geostatistical analysis to develop an empirical model of OC burial in water bodies of the CONUS. Our results indicate that CONUS water bodies sequester 20.8 (95% CI: 9.4-65.8) Tg C yr(-1), and spatial patterns in OC burial are strongly influenced by water body type, size, and abundance; land use; and soil and vegetation characteristics in surrounding areas. Carbon burial is greatest in the central and southeastern regions of the CONUS, where cultivation and an abundance of small water bodies enhance accumulation of sediment and OC in aquatic environments.

  20. Grassland fire effect on soil organic carbon reservoirs in semiarid environment

    NASA Astrophysics Data System (ADS)

    Novara, A.; Gristina, L.; Rühl, J.; Pasta, S.; D'Angelo, G.; La Mantia, T.; Pereira, P.

    2013-07-01

    The aim of this work was to investigate the effect of a experimental fire, used for grassland management, on soil organic carbon (SOC) reservoirs. The study was carried out on Hyparrhenia hirta (L.) Stapf (Hh) grassland and Ampelodesmos mauritanicus (Desf.) T. Durand and Schinz (Am) grasslands, located in the north of Sicily. Soil samples were collected at 0-5 cm before and after experimental fire and SOC was measured. During grassland fire soil surface temperature was monitored. Biomass of both grasses was analyzed in order to determine dry weight and its chemical composition. The results showed that SOC varied significantly with vegetation cover, while it is not affected in the short period by grassland fire. Am grassland stored more SOC compared with Hh grassland thanks to lower content in biomass of labile carbon pool. No significant difference was observed in SOC before and after fire which could be caused by several factors: first, in both grassland types the measured soil temperature during fire was low due to thin litter layers; second, in semiarid environment higher mineralization rate results in lower soil carbon labile pool; and third, the C stored in the finest soil fractions, physical protected, is not affected by fire.

  1. Development of a combined isotopic and mass-balance approach to determine dissolved organic carbon sources in eutrophic reservoirs.

    PubMed

    Pierson-Wickmann, Anne-Catherine; Gruau, Gérard; Jardé, Emilie; Gaury, Nicolas; Brient, Luc; Lengronne, Marion; Crocq, André; Helle, Daniel; Lambert, Thibault

    2011-04-01

    A combined mass-balance and stable isotope approach was set up to identify and quantify dissolved organic carbon (DOC) sources in a DOC-rich (9mgL(-1)) eutrophic reservoir located in Western France and used for drinking water supply (so-called Rophemel reservoir). The mass-balance approach consisted in measuring the flux of allochthonous DOC on a daily basis, and in comparing it with the effective (measured) DOC concentration of the reservoir. The isotopic approach consisted, for its part, in measuring the carbon isotope ratios (δ(13)C values) of both allochthonous and autochthonous DOC sources, and comparing these values with the δ(13)C values of the reservoir DOC. Results from both approaches were consistent pointing out for a DOC of 100% allochthonous origin. In particular, the δ(13)C values of the DOC recovered in the reservoir (-28.5±0.2‰; n=22) during the algal bloom season (May-September) showed no trace of an autochthonous contribution (δ(13)C in algae=-30.1±0.3‰; n=2) being indistinguishable from the δ(13)C values of allochthonous DOC from inflowing rivers (-28.6±0.1‰; n=8). These results demonstrate that eutrophication is not responsible for the high DOC concentrations observed in the Rophemel reservoir and that limiting eutrophication of this reservoir will not reduce the potential formation of disinfection by-products during water treatment. The methodology developed in this study based on a complementary isotopic and mass-balance approach provides a powerful tool, suitable to identify and quantify DOC sources in eutrophic, DOC-contaminated reservoirs.

  2. Modeling naturally fractured carbonate as potential CGS reservoir: a case study from Sulcis Basin.

    NASA Astrophysics Data System (ADS)

    Chiara Tartarello, Maria; Bigi, Sabina; Ruggiero, Livio

    2017-04-01

    The naturally fractured carbonates have a great potential for Carbon Geological Storage purpose because they could offer the possibility for storage in that areas where no sandstone are available. In Italy, we studied the Sulcis Basin, an area situated in SW Sardinia, where the "Miliolitico Fm." represents the potential reservoir. This Formation consists of well bedded, about 50 m thick, mudstones and grainstones with Miliolidae, deposited in a lagoon environment during the Early Eocene. This formation has a very low primary porosity and permeability, so it is essential to characterize the fracture network that characterize the reservoir's capacity. We performed a detailed fracture analysis at the outcrop, using scan lines and scan areas techniques. We measured the fractures spacing, aperture, length and connectivity both linearly and on a surface. These parameters were used to build several Discrete Fracture Model, using Move 2016 (Midland Valley). In particular DFN were constructed varying length and aperture values to evaluate their influence on the total secondary porosity. The same approach was also utilized in the Nuraxi Figus coal mine, where the Miliolitico crops out at a depth of -480 m b.s.l., in more confined pressure condition. Here we collected detailed scan lines. Major fractures/faults that cross the whole tunnel were also measured. These data were integrated with the previous ones for the DFN generation. A separate fracture model were generated to represent the fault network, to evaluate the different component of the brittle deformation (small fault and fractures). The fracture modeling was performed using Move 2016 and Petrel (Schlumberger); than the results were compared. The results show that most of the secondary permeability and porosity is due to faults, through which fluid circulate. Some fractures sometimes are affected by karst phenomena, that influence their aperture.

  3. Enhanced carbonate reservoir model for an old reservoir utilizing new techniques: The Schaben Field (Mississippian), Ness County, Kansas

    SciTech Connect

    Carr, T.P.; Guy, W.J.; Franseen, E.K.; Bhattacharya, S. )

    1996-01-01

    The Pennsylvanian-Mississippian unconformity is a major stratigraphic event in Kansas that truncates rocks ranging from Precambrian to Mississippian. Many of the 6,000 fields in Kansas are located immediately beneath this unconformity. One example, Schaben Field located in Ness County, Kansas, has produced approximately 9 million barrels since it was discovered in 1963. Production is from the Mississippian (Osagian) cherty dolomites beneath the inconformity. The field was initially developed on a regular forty-acre spacing, but recent drilling has demonstrated the potential for additional targeted infill drilling. To develop an enhanced reservoir model for the Schabin field modern core, log, and well data were integrated with the existing data. New techniques such as [open quotes]Pseudoseismic[close quotes] and the [open quotes]Super[close quotes] Pickett plot were used to leverage the existing data and provide tools for analysis and 3D visualization. The pseudoseismic approach uses well-logs within a standard 3D seismic visualization system to provide a detailed macroscale view of karst patterns. The petrophysical analyses using the [open quotes]Super[close quotes] Pickett plot were used to recognize subtle trends and patterns for each of multiple reservoir intervals. Visual and petrographic examination of core from the field confirms karst development and indicates multiple stages of fracturing, brecciation, and dissolution features that were important in controlling and modifying development of reservoirs. The understanding of the reservoir heterogeneities resulting from the paleokarst model at Schaben field emphasizes the importance of integrating available data with new techniques to provide a predictive tool for discovery of additional pay within existing subunconformity fields in Kansas.

  4. Enhanced carbonate reservoir model for an old reservoir utilizing new techniques: The Schaben Field (Mississippian), Ness County, Kansas

    SciTech Connect

    Carr, T.P.; Guy, W.J.; Franseen, E.K.; Bhattacharya, S.

    1996-12-31

    The Pennsylvanian-Mississippian unconformity is a major stratigraphic event in Kansas that truncates rocks ranging from Precambrian to Mississippian. Many of the 6,000 fields in Kansas are located immediately beneath this unconformity. One example, Schaben Field located in Ness County, Kansas, has produced approximately 9 million barrels since it was discovered in 1963. Production is from the Mississippian (Osagian) cherty dolomites beneath the inconformity. The field was initially developed on a regular forty-acre spacing, but recent drilling has demonstrated the potential for additional targeted infill drilling. To develop an enhanced reservoir model for the Schabin field modern core, log, and well data were integrated with the existing data. New techniques such as {open_quotes}Pseudoseismic{close_quotes} and the {open_quotes}Super{close_quotes} Pickett plot were used to leverage the existing data and provide tools for analysis and 3D visualization. The pseudoseismic approach uses well-logs within a standard 3D seismic visualization system to provide a detailed macroscale view of karst patterns. The petrophysical analyses using the {open_quotes}Super{close_quotes} Pickett plot were used to recognize subtle trends and patterns for each of multiple reservoir intervals. Visual and petrographic examination of core from the field confirms karst development and indicates multiple stages of fracturing, brecciation, and dissolution features that were important in controlling and modifying development of reservoirs. The understanding of the reservoir heterogeneities resulting from the paleokarst model at Schaben field emphasizes the importance of integrating available data with new techniques to provide a predictive tool for discovery of additional pay within existing subunconformity fields in Kansas.

  5. Ground-Penetrating Radar and Dielectric Characterization of Shallow Reservoir Analogs in Central Texas Carbonates

    NASA Astrophysics Data System (ADS)

    Mukherjee, Damayanti; Heggy, Essam; Khan, Shuhab D.; Sullivan, Charlotte E.

    2007-10-01

    Lake Georgetown Spillway near Georgetown (Williamson County) in Central Texas exposes Albian rudist communities and associated depositional facies of the Edwards Formation, Fredericksburg Group. Capped by younger dolostones of the same group, they form important analogs for highly productive fresh-water aquifers and hydrocarbon reservoirs in carbonate environments. A 2D ground-penetrating radar (GPR) survey was conducted using a 400 MHz antenna with the Subsurface Interface Radar (SIR-3000) System by GSSI and tied to GPS data. Data constituting a grid were processed and numerical simulation performed for 3D visualization using the software REFLEX. Dielectric measurements of field-collected rock samples were carried out initially under vacuum dried condition and then under controlled amounts of moisture content (considering 100% saturation of pores of each sample after 2 hours of water treatment). For each sample, penetration depths were calculated for antenna frequencies of 100 and 400 MHz assuming GPR signal penetration in a homogeneous layer. This was followed by porosity-permeability measurements along with petrographic and X-ray diffraction studies. Real (ɛ1) and imaginary parts (ɛ2) of the dielectric permittivity (ɛ), when plotted against moisture content, demonstrated a greater range of ɛ-values for more permeable samples. The depths of penetration varied inversely with the permeability of the samples. The processed 2D GPR data and 3D simulation revealed mound structures below the spillway floor, each with a diameter of ~15-20m and a thickness of ~5m. Petrographic studies showed the dominance of mouldic porosity in these carbonates while X-ray diffraction results confirmed calcite and dolomite as the dominant mineralogy, although present in varying proportions. Silica peaks were encountered that possibly represented chert replacements seen in the thin-sections. We thus conclude that different carbonate units can be differentiated in the field by the GPR

  6. Carbonate reservoir characterization with pore type inversion using differential effective medium (DEM) model at "X" field, East Java

    NASA Astrophysics Data System (ADS)

    Rosid, M. S.; Wahyuni, S. D.; Haidar, M. W.

    2017-07-01

    Pore system in the carbonate reservoirs is very complex than in clastic rocks. There are three types of classification of pore types in carbonate rocks: interparticle, stiff, and crack. The complexity of the pore types can cause changes in P-wave velocity by 40 %, as well as create a carbonate reservoir characterization becomes difficult when the S wave estimation is done only with the type of dominant pore (interparticle). Therefore, modeling the elastic moduli of rocks become essential to solve the problem of complexity of pore types in carbonate rocks. Differential Effective Medium (DEM) is a method of modeling the elastic moduli of rocks that takes into account the heterogeneity of types of pores in carbonate rocks by adding pore-type inclusions little by little into the parent material (host material) until the proportion of the material is reached. In addition, to the elastic moduli which have taken into account the heterogeneity of pore type. The inversion result shows that carbonate reservoir at "X" field is dominated by crack pore type and the relation between S wave and P wave is expressed by VS=-0.05 VP2+VP-1.1 and not in linear correlation.

  7. Chemical and physical characteristics of water and sediment in Scofield Reservoir, Carbon County, Utah

    USGS Publications Warehouse

    Waddell, Kidd M.; Darby, D.W.; Theobald, S.M.

    1985-01-01

    Evaluations based on the nutrient content of the inflow, outflow, water in storage, and the dissolved-oxygen depletion during the summer indicate that the trophic state of Scofield Reservoir is borderline between mesotrophic and eutrophic and may become highly eutrophic unless corrective measures are taken to limit nutrient inflow. Sediment deposition in Scofield Reservoir during 1943-79 is estimated to be 3,000 acre-feet, and has decreased the original storage capacity of the reservoir by 4 percent. The sediment contains some coal, and age dating of those sediments (based on the radioisotope lead-210) indicates that most of the coal was deposited prior to about 1950. Scofield Reservoir is dimictic, with turnovers occurring in the spring and autumn. Water in the reservoir circulates completely to the bottom during turnovers. The concentration of dissolved oxygen decreases with depth except during parts of the turnover periods. Below an altitude of about 7,590 feet, where 20 percent of the water is stored, the concentration of dissolved oxygen was less than 2 milligrams per liter during most of the year. During the summer stratification period, the depletion of dissolved oxygen in the deeper layers is coincident with supersaturated conditions in the shallow layers; this is attributed to plant photosynthesis and bacterial respiration in the reservoir. During October 1,1979-August 31, 1980, the discharge-weighted average concentrations of dissolved solids was 195 milligrams per liter in the combined inflow from Fish, Pondtown, and Mud Creeks, and was 175 milligrams per liter in the outflow (and to the Price River). The smaller concentration in the outflow was due primarily to precipitation of calcium carbonate in the reservoir--about 80 percent of the decrease can be accounted for through loss as calcium carbonate. The estimated discharge-weighted average concentration of total nitrogen (dissolved plus suspended) in the combined inflow of Fish, Pondtown, and Mud

  8. Carbon cycling and net ecosystem production at an early stage of secondary succession in an abandoned coppice forest.

    PubMed

    Ohtsuka, Toshiyuki; Shizu, Yoko; Nishiwaki, Ai; Yashiro, Yuichiro; Koizumi, Hiroshi

    2010-07-01

    Secondary mixed forests are one of the dominant forest cover types in human-dominated temperate regions. However, our understanding of how secondary succession affects carbon cycling and carbon sequestration in these ecosystems is limited. We studied carbon cycling and net ecosystem production (NEP) over 4 years (2004-2008) in a cool-temperate deciduous forest at an early stage of secondary succession (18 years after clear-cutting). Net primary production of the 18-year-old forest in this study was 5.2 tC ha(-1 )year(-1), including below-ground coarse roots; this was partitioned into 2.5 tC ha(-1 )year(-1) biomass increment, 1.6 tC ha(-1 )year(-1) foliage litter, and 1.0 tC ha(-1 )year(-1) other woody detritus. The total amount of annual soil surface CO(2) efflux was 6.8 tC ha(-1 )year(-1), which included root respiration (1.9 tC ha(-1 )year(-1)) and heterotrophic respiration (RH) from soils (4.9 tC ha(-1 )year(-1)). The 18-year forest at this study site exhibited a great increase in biomass pool as a result of considerable total tree growth and low mortality of tree stems. In contrast, the soil organic matter (SOM) pool decreased markedly (-1.6 tC ha(-1 )year(-1)), although further study of below-ground detritus production and RH of SOM decomposition is needed. This young 18-year forest was a weak carbon sink (0.9 tC ha(-1 )year(-1)) at this stage of secondary succession. The NEP of this 18-year forest is likely to increase gradually because biomass increases with tree growth and with the improvement of the SOM pool through increasing litter and dead wood production with stand development.

  9. The economics of carbon dioxide transport by pipeline and storage in saline aquifers and oil reservoirs

    NASA Astrophysics Data System (ADS)

    McCoy, Sean T.

    Large reductions in carbon dioxide (CO2) emissions are needed to mitigate the impacts of climate change. One method of achieving such reductions is CO2 capture and storage (CCS). CCS requires the capture of carbon dioxide (CO2) at a large industrial facility, such as a power plant, and its transport to a geological storage site where CO2 is sequestered, if implemented, CCS could allow fossil fuels to be used with little or no CO2 emissions until alternative energy sources are more widely deployed. Large volumes of CO2 are most efficiently transported by pipeline and stored either in deep saline aquifers or in oil reservoirs, where CO2 is used for enhanced oil recovery (EOR). This thesis describes a suite of models developed to estimate the project-specific cost of CO2 transport and storage. Engineering-economic models of pipeline CO2 transport, CO2flood EOR, and aquifer storage were developed for this purpose. The models incorporate a probabilistic analysis capability that is used to quantify the sensitivity of transport and storage cost to variability and uncertainty in the model input parameters. The cost of CO2 pipeline transport is shown to be sensitive to the region of construction, in addition to factors such as the length and design capacity of the pipeline. The cost of CO2 storage in saline aquifers is shown to be most sensitive to factors affecting site characterization cost. For EOR projects, CO2 storage has traditionally been a secondary effect of oil recovery; thus, a levelized cost of CO2 storage cannot be defined. Instead EOR projects were evaluated based on the breakeven price of CO2 (i.e., the price of CO2 at which the project net present value is zero). The breakeven CO2 price is shown to be most sensitive to oil prices, losses of CO2 outside the productive zone of the reservoir, and reservoir pressure. Future research should include collection and aggregation of more specific data characterizing possible sites for aquifer storage and applications

  10. the COS-Dwarfs survey: the carbon reservoir around sub-L* galaxies

    SciTech Connect

    Bordoloi, Rongmon; Tumlinson, Jason; Peeples, Molly S.; Fox, Andrew J.; Thom, Christopher; Werk, Jessica K.; Prochaska, J. Xavier; Tripp, Todd M.; Katz, Neal; Burchett, Joseph N.; Davé, Romeel; Ford, Amanda Brady; Weinberg, David H.; Kollmeier, Juna A.

    2014-12-01

    We report new observations of circumgalactic gas from the COS-Dwarfs survey, a systematic investigation of the gaseous halos around 43 low-mass z ≤ 0.1 galaxies using background QSOs observed with the Cosmic Origins Spectrograph. From the projected one-dimensional and two-dimensional distribution of C IV absorption, we find that C IV is detected out to ≈100 kpc (corresponding roughly to ≈0.5 R {sub vir}) of the host galaxies. The C IV absorption strength falls off radially as a power law, and beyond ≈0.5 R {sub vir}, no C IV absorption is detected above our sensitivity limit of ≈50-100 mÅ. We find a tentative correlation between detected C IV absorption strength and star formation, paralleling the strong correlation seen in highly ionized oxygen for L ∼ L* galaxies by the COS-Halos survey. The data imply a large carbon reservoir in the circumgalactic medium (CGM) of these galaxies, corresponding to a minimum carbon mass of ≳ 1.2 × 10{sup 6} M {sub ☉} out to ∼110 kpc. This mass is comparable to the carbon mass in the interstellar medium and exceeds the carbon mass currently in the stars of these galaxies. The C IV absorption seen around these sub-L* galaxies can account for almost two-thirds of all W{sub r} ≥ 100 mÅ C IV absorption detected at low z. Comparing the C IV covering fraction with hydrodynamical simulations, we find that an energy-driven wind model is consistent with the observations whereas a wind model of constant velocity fails to reproduce the CGM or the galaxy properties.

  11. What is below the support layer affects carbon nanotube growth: an iron catalyst reservoir yields taller nanotube carpets.

    PubMed

    Shawat, E; Mor, V; Oakes, L; Fleger, Y; Pint, C L; Nessim, G D

    2014-01-01

    Here we demonstrate an approach to enhance the growth of vertically aligned carbon nanotubes (CNTs) by including a catalyst reservoir underneath the thin-film alumina catalyst underlayer. This reservoir led to enhanced CNT growth due to the migration of catalytic material from below the underlayer up to the surface through alumina pinholes during processing. This led to the formation of large Fe particles, which in turn influenced the morphology evolution of the catalytic iron surface layer through Ostwald ripening. With inclusion of this catalyst reservoir, we observed CNT growth up to 100% taller than that observed without the catalyst reservoir consistently across a wide range of annealing and growth durations. Imaging studies of catalyst layers both for different annealing times and for different alumina support layer thicknesses demonstrate that the surface exposure of metal from the reservoir leads to an active population of smaller catalyst particles upon annealing as opposed to a bimodal catalyst size distribution that appears without inclusion of a reservoir. Overall, the mechanism for growth enhancement we present here demonstrates a new route to engineering efficient catalyst structures to overcome the limitations of CNT growth processes.

  12. Geochemical analysis of atlantic rim water, carbon county, wyoming: New applications for characterizing coalbed natural gas reservoirs

    USGS Publications Warehouse

    McLaughlin, J.F.; Frost, C.D.; Sharma, Shruti

    2011-01-01

    Coalbed natural gas (CBNG) production typically requires the extraction of large volumes of water from target formations, thereby influencing any associated reservoir systems. We describe isotopic tracers that provide immediate data on the presence or absence of biogenic natural gas and the identify methane-containing reservoirs are hydrologically confined. Isotopes of dissolved inorganic carbon and strontium, along with water quality data, were used to characterize the CBNG reservoirs and hydrogeologic systems of Wyoming's Atlantic Rim. Water was analyzed from a stream, springs, and CBNG wells. Strontium isotopic composition and major ion geochemistry identify two groups of surface water samples. Muddy Creek and Mesaverde Group spring samples are Ca-Mg-S04-type water with higher 87Sr/86Sr, reflecting relatively young groundwater recharged from precipitation in the Sierra Madre. Groundwaters emitted from the Lewis Shale springs are Na-HCO3-type waters with lower 87Sr/86Sr, reflecting sulfate reduction and more extensive water-rock interaction. To distinguish coalbed waters, methanogenically enriched ??13CDIC wasused from other natural waters. Enriched ??13CDIC, between -3.6 and +13.3???, identified spring water that likely originates from Mesaverde coalbed reservoirs. Strongly positive ??13CDIC, between +12.6 and +22.8???, identified those coalbed reservoirs that are confined, whereas lower ??13CDIC, between +0.0 and +9.9???, identified wells within unconfined reservoir systems. Copyright ?? 2011. The American Association of Petroleum Geologists. All rights reserved.

  13. Dynamic three-dimensional pore-scale imaging of reaction in a carbonate at reservoir conditions.

    PubMed

    Menke, Hannah P; Bijeljic, Branko; Andrew, Matthew G; Blunt, Martin J

    2015-04-07

    Quantifying CO2 transport and average effective reaction rates in the subsurface is essential to assess the risks associated with underground carbon capture and storage. We use X-ray microtomography to investigate dynamic pore structure evolution in situ at temperatures and pressures representative of underground reservoirs and aquifers. A 4 mm diameter Ketton carbonate core is injected with CO2-saturated brine at 50 °C and 10 MPa while tomographic images are taken at 15 min intervals with a 3.8 μm spatial resolution over a period of 2(1/2) h. An approximate doubling of porosity with only a 3.6% increase in surface area to volume ratio is measured from the images. Pore-scale direct simulation and network modeling on the images quantify an order of magnitude increase in permeability and an appreciable alteration of the velocity field. We study the uniform reaction regime, with dissolution throughout the core. However, at the pore scale, we see variations in the degree of dissolution with an overall reaction rate which is approximately 14 times lower than estimated from batch measurements. This work implies that in heterogeneous rocks, pore-scale transport of reactants limits dissolution and can reduce the average effective reaction rate by an order of magnitude.

  14. Geoscience/Engineering Characterization of the Interwell Environment in Carbonate Reservoirs Based on Outcrop Analogs, Permian Basin, West Texas and New Mexico.

    SciTech Connect

    Lucia, F.J.; Kerans, C.

    1997-05-29

    The objective of this project is to investigate styles of reservoir heterogeneity found in low permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study.

  15. Abandoned Channel Fill Sequences in Tidal Estuaries

    NASA Astrophysics Data System (ADS)

    Gray, A. B.; Pasternack, G. B.; Goni, M. A.; Watson, E. B.

    2014-12-01

    This study proposes a modification of the current model for abandoned channel fill stratigraphy produced in unidirectional flow river reaches to incorporate seasonal tidal deposition. Evidence supporting this concept came from a study of two consecutive channel abandonment sequences in Ropers Slough of the lower Eel River Estuary in northern California. Aerial photographs showed that Ropers Slough was abandoned around 1943, reoccupied after the 1964 flood, and abandoned again in 1974 with fill continuing to the present. Planform geomorphic characteristics derived from these images were used in conjunction with sub-cm resolution stratigraphic analyses to describe the depositional environment processes and their resultant sedimentary deposits. Results showed that both abandonment sequences recorded quasi-annual scale fluvial/tidal deposition couplets. In both cases tidal deposits contained very little sand, and were higher in organic and inorganic carbon content than the sandier fluvial through-flow deposits. However, the two abandonment fills differed significantly in terms of the temporal progression of channel narrowing and fluvial sediment deposition characteristics. The first abandonment sequence led to a more rapid narrowing of Ropers Slough and produced deposits with a positive relationship between grain size/deposit thickness and discharge. The second abandonment resulted in a much slower narrowing of Ropers Slough and generally thinner fluvial deposits with no clear relationship between grain size/deposit thickness and discharge. The δ13C values and organic nitrogen to organic carbon ratios of deposits from the first phase overlapped with Eel River suspended sediment characteristics found for low flows (1-5 times mean discharge), while those of the second phase were consistent suspended sediment from higher flows (7-10 times mean discharge). The abandoned channel fill sequences appeared to differ due to the topographic steering of bed sediment transport and

  16. Improved Oil Recovery in Mississippian Carbonate Reservoirs of Kansas - Near-Term, Class II

    SciTech Connect

    Carr, Timothy R.; Green, Don W.; Willhite, G. Paul

    2001-10-30

    The focus of this project was development and demonstration of cost-effective reservoir description and management technologies to extend the economic life of mature reservoirs in Kansas and the mid-continent.

  17. 3D modeling of gas/water distribution in water-bearing carbonate gas reservoirs: the Longwangmiao gas field, China

    NASA Astrophysics Data System (ADS)

    Ou, Chenghua; Li, ChaoChun; Ma, Zhonggao

    2016-10-01

    A water-bearing carbonate gas reservoir is an important natural gas resource being developed worldwide. Due to the long-term water/rock/gas interaction during geological evolution, complex gas/water distribution has formed under the superposed effect of sedimentary facies, reservoir space facies and gravity difference of fluid facies. In view of these challenges, on the basis of the conventional three-stage modeling method, this paper presents a modelling method controlled by four-stage facies to develop 3D model of a water-bearing carbonate gas reservoir. Key to this method is the reservoir property modelling controlled by two-stage facies, and the fluid property modelling controlled by another two-stage facies. The prerequisite of this method is a reliable database obtained from solid geological investigation. On the basis of illustrating the principles of the modelling method controlled by four-stage facies, this paper further implements systematically modeling of the heterogeneous gas/water distribution of the Longwangmiao carbonate formation in the Moxi-Gaoshiti area, Sichuan basin, China.

  18. Highly CO2-supersaturated melts in the Pannonian lithospheric mantle - A transient carbon reservoir?

    NASA Astrophysics Data System (ADS)

    Créon, Laura; Rouchon, Virgile; Youssef, Souhail; Rosenberg, Elisabeth; Delpech, Guillaume; Szabó, Csaba; Remusat, Laurent; Mostefaoui, Smail; Asimow, Paul D.; Antoshechkina, Paula M.; Ghiorso, Mark S.; Boller, Elodie; Guyot, François

    2017-08-01

    Subduction of carbonated crust is widely believed to generate a flux of carbon into the base of the continental lithospheric mantle, which in turn is the likely source of widespread volcanic and non-volcanic CO2 degassing in active tectonic intracontinental settings such as rifts, continental margin arcs and back-arc domains. However, the magnitude of the carbon flux through the lithosphere and the budget of stored carbon held within the lithospheric reservoir are both poorly known. We provide new constraints on the CO2 budget of the lithospheric mantle below the Pannonian Basin (Central Europe) through the study of a suite of xenoliths from the Bakony-Balaton Highland Volcanic Field. Trails of secondary fluid inclusions, silicate melt inclusions, networks of melt veins, and melt pockets with large and abundant vesicles provide numerous lines of evidence that mantle metasomatism affected the lithosphere beneath this region. We obtain a quantitative estimate of the CO2 budget of the mantle below the Pannonian Basin using a combination of innovative analytical and modeling approaches: (1) synchrotron X-ray microtomography, (2) NanoSIMS, Raman spectroscopy and microthermometry, and (3) thermodynamic models (Rhyolite-MELTS). The three-dimensional volumes reconstructed from synchrotron X-ray microtomography allow us to quantify the proportions of all petrographic phases in the samples and to visualize their textural relationships. The concentration of CO2 in glass veins and pockets ranges from 0.27 to 0.96 wt.%, higher than in typical arc magmas (0-0.25 wt.% CO2), whereas the H2O concentration ranges from 0.54 to 4.25 wt.%, on the low end for estimated primitive arc magmas (1.9-6.3 wt.% H2O). Trapping pressures for vesicles were determined by comparing CO2 concentrations in glass to CO2 saturation as a function of pressure in silicate melts, suggesting pressures between 0.69 to 1.78 GPa. These values are generally higher than trapping pressures for fluid inclusions

  19. Experiments and modeling of variably permeable carbonate reservoir samples in contact with CO₂-acidified brines

    DOE PAGES

    Smith, Megan M.; Hao, Yue; Mason, Harris E.; ...

    2014-12-31

    Reactive experiments were performed to expose sample cores from the Arbuckle carbonate reservoir to CO₂-acidified brine under reservoir temperature and pressure conditions. The samples consisted of dolomite with varying quantities of calcite and silica/chert. The timescales of monitored pressure decline across each sample in response to CO₂ exposure, as well as the amount of and nature of dissolution features, varied widely among these three experiments. For all samples cores, the experimentally measured initial permeability was at least one order of magnitude or more lower than the values estimated from downhole methods. Nondestructive X-ray computed tomography (XRCT) imaging revealed dissolution featuresmore » including “wormholes,” removal of fracture-filling crystals, and widening of pre-existing pore spaces. In the injection zone sample, multiple fractures may have contributed to the high initial permeability of this core and restricted the distribution of CO₂-induced mineral dissolution. In contrast, the pre-existing porosity of the baffle zone sample was much lower and less connected, leading to a lower initial permeability and contributing to the development of a single dissolution channel. While calcite may make up only a small percentage of the overall sample composition, its location and the effects of its dissolution have an outsized effect on permeability responses to CO₂ exposure. The XRCT data presented here are informative for building the model domain for numerical simulations of these experiments but require calibration by higher resolution means to confidently evaluate different porosity-permeability relationships.« less

  20. Hydrology of the Valley-fill and carbonate-rock reservoirs, Pahrump Valley, Nevada-California

    USGS Publications Warehouse

    Malmberg, Glenn T.

    1967-01-01

    This is the second appraisal of the water supply of Pahrump Valley, made 15 years after the first cooperative study. In the first report the average recharge was estimated to be 23,000 acre-feet per year, only 1,000 acre-feet more than the estimate made in this report. All this recharge was considered to be available for development. Because of the difficulty in salvaging the subsurface outflow from the deep carbonate-rock reservoir, this report concludes that the perennial yield may be only 25,000 acre-feet. In 1875, Bennetts and Manse Springs reportedly discharged a total of nearly 10,000 acre-feet of water from the valley-fill reservoir. After the construction of several flowing wells in 1910, the spring discharge began to decline. In the mid-1940's many irrigation wells were drilled, and large-capacity pumps were installed. During the 4-year period of this study (1959-62), the net pumping draft averaged about 25,000 acre-feet per year, or about twice the estimated yield. In 1962 Bennetts Spring was dry, and the discharge from Marse Spring was only 1,400 acre-feet. During the period February 1959-February 1962, pumping caused an estimated storage depletion of 45,000 acre-feet, or 15,000 acre-feet per year. If the overdraft is maintained, depletion of stored water will continue and pumping costs will increase. Water levels in the vicinity of the Pahrump, Manse, and Fowler Ranches declined more than ]0 feet in response to the pumping during this period, and they can be expected to continue to decline at ,the projected rate of more than 3 feet per year. The chemical quality of the pumped water has been satisfactory for irrigation and domestic use. Recycling of water pumped or irrigation, however, could result in deterioration of the water quality with time.

  1. Soil organic carbon in Apolobamba (Bolivia): Quantity and quality of the reservoir

    NASA Astrophysics Data System (ADS)

    Muñoz, M. Á.; Faz, A.

    2009-04-01

    soluble organic carbon (WSOC) were messure. In addition, 13C MNR technique was used in surface samples in each plot in order to determine the main carbonide groups: alkyl, O-alkyl, aromatic and carboxilic. Results were discussing through statistical analyses. Soil profile datas exhibited very low TOC in Ulla-Ulla zone including the surface horizon. Sampling plot results showed maximum TOC contents in Wakampata and Puyo-Puyo surface samples; on the other hand, Sucondori, Caballchiñuni and Ulla-Ulla presented minimum contents. Generally speaking, low and medium WSOC inputs were determined in surface and subsurface samples, respectively, in studied areas. Moreover, Wakampata and Japu zones presented high O-alkyl percentages; it could be related to highest polysacharide concentrations and the easiest SOM degradation, taking into account alkyl/O-alkyl ratios. On the contrary, Ulla-Ulla and Caballchiñuni exhibited highest carboxilic percentages pointing out a SOM oxidation increase. In conclusion, Apolobamba soils presented different SOC conditions. There were some zones which could be characterized as excellent carbon reservoirs due to high SOM quantity and quality; however, in other census places could be identify a certain soil exhaustion degree, as a consequence to the soil overexploitation due to the cattle camelid concentrations both the natural wind erosion in these zones. It should be carried out conservation actions in order to improve the carbon sink and to preserve the soil and the biodiversity in Apolobamba.

  2. The effects of land abandonment and long-term afforestation practices on the organic carbon and lignin content of a Mediteranean soil

    NASA Astrophysics Data System (ADS)

    Stijsiger, Romy; Nadal-Romero, Estela; Campo, Julian; Cammeraat, Erik

    2016-04-01

    Afforestation is an important strategy that can decrease atmospheric carbon in sequestering it in biomass and soils (Pérez-Crusado et al., 2014). In Spain an active afforestation program was adopted in the 1950s, when after wide spread land abandonment the soils were severely eroded (FAO, 2015). In this research the organic carbon and lignin content of the soils in the Araguás catchment area in the Spanish Pyrenees were examined. This research is part of a larger research examining the effect of afforestation over time (Med Afforest Project, PIEF-GA-2013-624974). The research area was afforested with both the P. sylvestris (Scotts Pine) and the P.nigra (Black Pine). Both sites were compared to bare soil (representing severely eroded soil), natural secondary succession (re-vegetation) and meadows. The method used to assess the lignin content is Curie-point pyrolysis with tetramethylammonium hydroxide (TMAH). The results showed a reducing trend for the soil organic carbon (SOC) content with depth. The highest SOC and lignin contents in the topsoil were found under P.nigra and secondary succession. This decline in lignin content corresponds with a high degradation rate (Ad/Al) in the top soil and lower degradation rates in depths of >20 cm. Meadows showed an increased SOC content in deeper horizons, which corresponds to high lignin content as well. In which the meadows showed an increase in lignin content for the soil depths of >20 cm that was unusual and could not be explained by the S/G and P/G ratios and the degradation ratio (Ad/Al). According to the results, P. nigra was the best afforestation practice for increasing the SOC and lignin contents in the soil. The P. sylvestris was considered but proved to be less successful than natural secondary succession. Acknowledgements This research was supported by a Marie Curie Intra-European Fellowship in the project "MED-AFFOREST" (PIEF-GA-2013-624974). JC also acknowledges the VALi+d postdoctoral contract (APOSTD/2014

  3. Regional-scale porosity and permeability variations in Upper Devonian Leduc buildups: Implications for reservoir development and prediction in carbonates

    SciTech Connect

    Amthor, J.E.; Mountjoy, E.W.; Machel, H.G.

    1994-10-01

    Upper Devonian carbonate rocks of the Rimbey-Meadowbrook reef trend in the subsurface of central Alberta are characterized by a wide range of porosity and permeability values. Dolostones show the highest values of absolute and average horizontal and vertical permeability. For all rock types, horizontal permeability averages tens of times to several hundred times the vertical permeability. If considered irrespective of burial depth, limestones and dolomitic limestones are more porous than dolostones. There is an overall decrease of porosity and permeability in Leduc Formation carbonates with increasing burial depth and thermal maturity along the reef trend. At relatively shallow burial depths (<2000 m), limestone and dolomitized buildups have comparable porosity values and distributions. Dolomitization has resulted mainly in redistribution of primary limestone porosity to secondary dolomite porosity types with a concomitant minor increase in permeability. At greater burial depths (>2000 m), dolostones are significantly more porous and permeable than limestones. The better porosity and permeability of dolostones relative to limestones at greater depths is of economic significance for exploration in Upper Devonian carbonates of the deep Alberta basin (and probably other carbonate areas), where reservoirs are mostly found in dolostones and where limestones have a low reservoir potential and pose a considerable exploration risk. The best reservoir potential in the Leduc Formation of the deep Alberta basin occurs in dolomitized buildups that were connected to a regional conduit system.

  4. Key factors for determining groundwater impacts due to leakage from geologic carbon sequestration reservoirs

    SciTech Connect

    Carroll, Susan A.; Keating, Elizabeth; Mansoor, Kayyum; Dai, Zhenxue; Sun, Yunwei; Trainor-Guitton, Whitney; Brown, Chris; Bacon, Diana

    2014-09-07

    The National Risk Assessment Partnership (NRAP) is developing a science-based toolset for the analysis of potential impacts to groundwater chemistry from CO2 injection (www.netldoe.gov/nrap). The toolset adopts a stochastic approach in which predictions address uncertainties in shallow groundwater and leakage scenarios. It is derived from detailed physics and chemistry simulation results that are used to train more computationally efficient models, referred to here as reduced-order models (ROMs), for each component system. In particular, these tools can be used to help regulators and operators understand the expected sizes and longevity of plumes in pH, TDS, and dissolved metals that could result from a leakage of brine and/or CO2 from a storage reservoir into aquifers. This information can inform, for example, decisions on monitoring strategies that are both effective and efficient. We have used this approach to develop predictive reduced-order models for two common types of reservoirs, but the approach could be used to develop a model for a specific aquifer or other common types of aquifers. In this paper we describe potential impacts to groundwater quality due to CO2 and brine leakage, discuss an approach to calculate thresholds under which no impact to groundwater occurs, describe the time scale for impact on groundwater, and discuss the probability of detecting a groundwater plume should leakage occur. To facilitate this, multi-phase flow and reactive transport simulations and emulations were developed for two classes of aquifers, considering uncertainty in leakage source terms and aquifer hydrogeology. We targeted an unconfined fractured carbonate aquifer based on the Edwards aquifer in Texas and a confined alluvium aquifer based on the High Plains Aquifer in Kansas, which share characteristics typical of many drinking water aquifers in the United States. The hypothetical leakage scenarios centered on the notion that wellbores

  5. Key factors for determining groundwater impacts due to leakage from geologic carbon sequestration reservoirs

    DOE PAGES

    Carroll, Susan A.; Keating, Elizabeth; Mansoor, Kayyum; ...

    2014-09-07

    The National Risk Assessment Partnership (NRAP) is developing a science-based toolset for the analysis of potential impacts to groundwater chemistry from CO2 injection (www.netldoe.gov/nrap). The toolset adopts a stochastic approach in which predictions address uncertainties in shallow groundwater and leakage scenarios. It is derived from detailed physics and chemistry simulation results that are used to train more computationally efficient models, referred to here as reduced-order models (ROMs), for each component system. In particular, these tools can be used to help regulators and operators understand the expected sizes and longevity of plumes in pH, TDS, and dissolved metals that could resultmore » from a leakage of brine and/or CO2 from a storage reservoir into aquifers. This information can inform, for example, decisions on monitoring strategies that are both effective and efficient. We have used this approach to develop predictive reduced-order models for two common types of reservoirs, but the approach could be used to develop a model for a specific aquifer or other common types of aquifers. In this paper we describe potential impacts to groundwater quality due to CO2 and brine leakage, discuss an approach to calculate thresholds under which no impact to groundwater occurs, describe the time scale for impact on groundwater, and discuss the probability of detecting a groundwater plume should leakage occur. To facilitate this, multi-phase flow and reactive transport simulations and emulations were developed for two classes of aquifers, considering uncertainty in leakage source terms and aquifer hydrogeology. We targeted an unconfined fractured carbonate aquifer based on the Edwards aquifer in Texas and a confined alluvium aquifer based on the High Plains Aquifer in Kansas, which share characteristics typical of many drinking water aquifers in the United States. The hypothetical leakage scenarios centered on the notion that wellbores are the most likely

  6. Carbonate mound reservoirs in the paradox formation: An outcrop analogue along the San Juan River, Southeastern Utah

    SciTech Connect

    Chidsey, T. C. Jr.; Morgan, C.D.; Eby, D.E.

    1996-06-01

    Carbonate mound reservoirs within the Pennsylvanian (Desmoinesian) Paradox Formation are major producers of oil and gas in the Paradox basin of Utah, Colorado, and Arizona. Outcrops of the Paradox Formation along the San Juan River of southeastern Utah provide small-scale analogues of reservoir heterogeneity, flow barriers and baffles, lithofacies, and geometry. These characteristics can be used in reservoir simulation models for secondary/tertiary recovery of oil from small fields in the basin. Exposures of the Paradox Formation Ismay zone in the Wild Horse Canyon area display lateral facies changes from phylloid algal mounds to off-mound detrital wedges or fans bounded at the top by a flooding surface. The phylloid mounds are composed of bafflestone, skeletal grainstone, packstone, and cementstone. Algal plates, brachiopods, bryozoans, and rugose corals are commonly found in the phylloid mounds. The mound wall is composed of rudstone, lumpstone, and cementstone. The detrital fan consists of transported algal material, grainstone, and mudstone with open-marine fossils. Within the mound complex is an inter-mound trough tentatively interpreted to be a tidal channel. The geometry and composition of the rocks in the trough significantly add to the overall heterogeneity of the mound. Reservoir models are being developed for possible water- and carbon-dioxide floods of small Paradox basin fields to determine the most effective secondary/tertiary recovery method. The models will include lithologic fabrics, flooding surfaces, and inter-mound troughs, based on the mound complex exposed at Wild Horse Canyon. This project may also provide reservoir information for simulation models in small Paleozoic carbonate mound fields in other basins worldwide.

  7. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir

    SciTech Connect

    1998-06-01

    The application of cyclic CO{sub 2}, often referred to as the CO{sub 2} Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO{sub 2} H-n-P process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital intensive miscible projects. Texaco Exploration and Production Inc. and the US Department of Energy have teamed up in an attempt to develop the CO{sub 2} Huff-n-Puff process in the Grayburg and San Andres formations, a light oil, shallow shelf carbonate reservoir that exists throughout the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir. The selected site for this demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico. The goals of the project are the development of guidelines for cost-effective selection of candidate reservoirs and wells, along with estimating recovery potential. This project has two defined budget periods. The first budget period primarily involves tasks associated with reservoir analysis and characterization, characterizing existing producibility problems, and reservoir simulation of the proposed technology. The final budget period covers the actual field demonstration of the proposed technology. Technology transfer spans the entire course of the project. This report covers the concluding tasks performed under the second budget period.

  8. A Microchip-based Endothelium Mimic Utilizing Open Reservoirs for Cell Immobilization and Integrated Carbon Ink Microelectrodes for Detection

    PubMed Central

    Hulvey, Matthew K; Martin, R. Scott

    2010-01-01

    This paper describes the fabrication and characterization of a microfluidic device that utilizes a reservoir-based approach for endothelial cell immobilization and integrated embedded carbon ink microelectrodes for the amperometric detection of extracellular nitric oxide (NO) release. The design utilizes a buffer channel to continuously introduce buffer or a plug of stimulant to the reservoir as well as a separate sampling channel that constantly withdraws buffer from the reservoir and over the microelectrode. A steel pin is used for both the fluidic connection to the sampling channel and to provide a quasi-reference electrode for the carbon ink microelectrode. Characterization of the device was performed using NO standards produced from a NONOate salt. Finally, NO release from a layer of immobilized endothelial cells was monitored and quantified using the system. This system holds promise as a means to electrochemically detect extracellular NO release from endothelial cells in either an array of reservoirs or concurrently with fluorescence-based intracellular NO measurements. PMID:18989663

  9. Determining Carbon and Oxygen Stable Isotope Systematics in Brines at Elevated p/T Conditions to Enhance Monitoring of CO2 Induced Processes in Carbon Storage Reservoirs

    NASA Astrophysics Data System (ADS)

    Becker, V.; Myrttinen, A.; Mayer, B.; Barth, J. A.

    2012-12-01

    Stable carbon isotope ratios (δ13C) are a powerful tool for inferring carbon sources and mixing ratios of injected and baseline CO2 in storage reservoirs. Furthermore, CO2 releasing and consuming processes can be deduced if the isotopic compositions of end-members are known. At low CO2 pressures (pCO2), oxygen isotope ratios (δ18O) of CO2 usually assume the δ18O of the water plus a temperature-dependent isotope fractionation factor. However, at very high CO2 pressures as they occur in CO2 storage reservoirs, the δ18O of the injected CO2 may in fact change the δ18O of the reservoir brine. Hence, changing δ18O of brine constitutes an additional tracer for reservoir-internal carbon dynamics and allows the determination of the amount of free phase CO2 present in the reservoir (Johnson et al. 2011). Further systematic research to quantify carbon and oxygen isotope fractionation between the involved inorganic carbon species (CO2, H2CO3, HCO3-, CO32-, carbonate minerals) and kinetic and equilibrium isotope effects during gas-water-rock interactions is necessary because p/T conditions and salinities in CO2 storage reservoirs may exceed the boundary conditions of typical environmental isotope applications, thereby limiting the accuracy of stable isotope monitoring approaches in deep saline formations (Becker et al. 2011). In doing so, it is crucial to compare isotopic patterns observed in laboratory experiments with artificial brines to similar experiments with original fluids from representative field sites to account for reactions of dissolved inorganic carbon (DIC) with minor brine components. In the CO2ISO-LABEL project, funded by the German Ministry for Education and Research, multiple series of laboratory experiments are conducted to determine the influence of pressure, temperature and brine composition on the δ13C of DIC and the δ18O of brines in water-CO2-rock reactions with special focus placed on kinetics and stable oxygen and carbon isotope fractionation

  10. Using Biosurfactants Produced from Agriculture Process Waste Streams to Improve Oil Recovery in Fractured Carbonate Reservoirs

    SciTech Connect

    Stephen Johnson; Mehdi Salehi; Karl Eisert; Sandra Fox

    2009-01-07

    This report describes the progress of our research during the first 30 months (10/01/2004 to 03/31/2007) of the original three-year project cycle. The project was terminated early due to DOE budget cuts. This was a joint project between the Tertiary Oil Recovery Project (TORP) at the University of Kansas and the Idaho National Laboratory (INL). The objective was to evaluate the use of low-cost biosurfactants produced from agriculture process waste streams to improve oil recovery in fractured carbonate reservoirs through wettability mediation. Biosurfactant for this project was produced using Bacillus subtilis 21332 and purified potato starch as the growth medium. The INL team produced the biosurfactant and characterized it as surfactin. INL supplied surfactin as required for the tests at KU as well as providing other microbiological services. Interfacial tension (IFT) between Soltrol 130 and both potential benchmark chemical surfactants and crude surfactin was measured over a range of concentrations. The performance of the crude surfactin preparation in reducing IFT was greater than any of the synthetic compounds throughout the concentration range studied but at low concentrations, sodium laureth sulfate (SLS) was closest to the surfactin, and was used as the benchmark in subsequent studies. Core characterization was carried out using both traditional flooding techniques to find porosity and permeability; and NMR/MRI to image cores and identify pore architecture and degree of heterogeneity. A cleaning regime was identified and developed to remove organic materials from cores and crushed carbonate rock. This allowed cores to be fully characterized and returned to a reproducible wettability state when coupled with a crude-oil aging regime. Rapid wettability assessments for crushed matrix material were developed, and used to inform slower Amott wettability tests. Initial static absorption experiments exposed limitations in the use of HPLC and TOC to determine

  11. Miocene carbonate reservoirs related to tectonic and thermal evolution of southeast Asian marginal basins

    SciTech Connect

    Fulthorpe, C.S.; Brodholt, J.P.; Jurdy, D.M.; Schlanger, S.O.

    1986-05-01

    The early Miocene global sea level rise and oceanic warming period allowed the tropical reef growth belt to expand and fostered the development of major carbonate buildups throughout southeast Asia. A regional paleogeographic reconstruction for 18 m.y. places reefal, shelf, and basinal facies in a tectonic setting of island arcs, subduction zones, and marginal basins. For typical basins, such as the Sulu, Celebes, and South China Sea basins, basin formation and sedimentation models have been developed based on ages inferred from identified marine magnetic anomalies and heat flow data. These basins have many of the attributes needed for hydrocarbon development and maturation. They accumulated sediment from pelagic sources and surrounding island arcs and landmasses fringed by reefs. During the early Miocene, limited water circulation in restricted basins, such as the Sulu and Celebes basins, may have induced dysaerobic conditions that enhanced organic carbon preservation. Models of marginal basin formation provide the basis for studying the time-dependent thermal histories of their sediment sequences. The authors models show that, for example, lower Miocene sediments deposited at a rate of 100 m/m.y. on 20-m.y.-old crust in a typical basin have just entered the oil-generation window. Lower sedimentation rates require deposition on younger crust in order for the sediments to reach an equivalent maturation stage. Estimates of the hydrocarbon potential of such marginal basins should be based on a sequential time-slice analysis of each basin in terms of sediment type, sedimentation rate, sea floor age and thermal regime, and the presence of reservoirs.

  12. CO2 wettability of seal and reservoir rocks and the implications for carbon geo-sequestration

    NASA Astrophysics Data System (ADS)

    Iglauer, Stefan; Pentland, C. H.; Busch, A.

    2015-01-01

    We review the literature data published on the topic of CO2 wettability of storage and seal rocks. We first introduce the concept of wettability and explain why it is important in the context of carbon geo-sequestration (CGS) projects, and review how it is measured. This is done to raise awareness of this parameter in the CGS community, which, as we show later on in this text, may have a dramatic impact on structural and residual trapping of CO2. These two trapping mechanisms would be severely and negatively affected in case of CO2-wet storage and/or seal rock. Overall, at the current state of the art, a substantial amount of work has been completed, and we find that: Sandstone and limestone, plus pure minerals such as quartz, calcite, feldspar, and mica are strongly water wet in a CO2-water system. Oil-wet limestone, oil-wet quartz, or coal is intermediate wet or CO2 wet in a CO2-water system. The contact angle alone is insufficient for predicting capillary pressures in reservoir or seal rocks. The current contact angle data have a large uncertainty. Solid theoretical understanding on a molecular level of rock-CO2-brine interactions is currently limited. In an ideal scenario, all seal and storage rocks in CGS formations are tested for their CO2 wettability. Achieving representative subsurface conditions (especially in terms of the rock surface) in the laboratory is of key importance but also very challenging.

  13. Transport of Organic Contaminants Mobilized from Coal through Sandstone Overlying a Geological Carbon Sequestration Reservoir

    SciTech Connect

    Zhong, Lirong; Cantrell, Kirk J.; Bacon, Diana H.; Shewell, Jesse L.

    2014-02-01

    Column experiments were conducted using a wetted sandstone rock installed in a tri-axial core holder to study the flow and transport of organic compounds mobilized by scCO2 under simulated geologic carbon storage (GCS) conditions. The sandstone rock was collected from a formation overlying a deep saline reservoir at a GCS demonstration site. Rock core effluent pressures were set at 0, 500, or 1000 psig and the core temperature was set at 20 or 50°C to simulate the transport to different subsurface depths. The concentrations of the organic compounds in the column effluent and their distribution within the sandstone core were monitored. Results indicate that the mobility though the core sample was much higher for BTEX compounds than for naphthalene. Retention of organic compounds from the vapor phase to the core appeared to be primarily controlled by partitioning from the vapor phase to the aqueous phase. Adsorption to the surfaces of the wetted sandstone was also significant for naphthalene. Reduced temperature and elevated pressure resulted in greater partitioning of the mobilized organic contaminants into the water phase.

  14. Finite Element Modeling of Water/Steam and Carbon Dioxide Heat and Fluid Transportation in Geothermal Reservoir

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Xing, H.; Zhang, H.

    2009-12-01

    Geothermal energy exploitation and carbon dioxide geosequestration are both attractive topics in renewable clean energy for an environmental society. The enhanced geothermal systems (EGS) have been raised both laboratorially and practically, which employ CO2 instead of water as a heat transmission medium. Our research focuses on numerical simulation of groundwater and carbon dioxide dominated geothermal reservoirs and gives a numerical procedure of coupled heat and fluid flow problems with phase changing by means of finite element method. A few of numerical models are carried out to simulate the drainage of a water/vapor dominated reservoir with CO2 injection. The phase changing of water and CO2 are both monitored as volume saturation or mass fraction, which gives a dynamic concept of the multiphase fluid circulation of CO2-EGS system.

  15. Determination of porosity and facies trends in a complex carbonate reservoir, by using 3-D seismic, borehole tools, and outcrop geology

    SciTech Connect

    Zacharakis, T.G. Jr.; Comet, J.N.; Murillo, A.A.

    1996-08-01

    Mesozoic carbonate reservoirs are found in the Mediterranean Sea, off the east coast of Spain. A wide variation of porosities are found in the core samples and logs: vuggy, breccia, fractures, and cavern porosity. In addition, complex Tertiary carbonate geometries include olistostromes, breccia bodies, and reef buildups, which are found on top of Mesozoic carbonates. Predicting the porosity trends within these oil productive reservoirs requires an understanding of how primary porosity was further enhanced by secondary processes, including fractures, karstification, and dolomitization in burial conditions. Through an extensive investigation of field histories, outcrop geology, and seismic data, a series of basic reservoir styles have been identified and characterized by well log signature and seismic response. The distribution pattern of the different reservoirs styles is highly heterogeneous, but by integrating subsurface data and outcrop analogs, it is possible to distinguish field-scale and local patterns of both vertical and local variations in reservoir properties. Finally, it is important to quantify these reservoir properties through the study of seismic attributes, such as amplitude variations, and log responses at the reservoir interval. By incorporating 3-D seismic data, through the use of seismic inversion, it is possible to predict porosity trends. Further, the use of geostatistics can lead to the prediction of reservoir development within the carbonate facies.

  16. Carbon dioxide emissions from Tucuruí reservoir (Amazon biome): New findings based on three-dimensional ecological model simulations.

    PubMed

    Curtarelli, Marcelo Pedroso; Ogashawara, Igor; de Araújo, Carlos Alberto Sampaio; Lorenzzetti, João Antônio; Leão, Joaquim Antônio Dionísio; Alcântara, Enner; Stech, José Luiz

    2016-05-01

    We used a three-dimensional model to assess the dynamics of diffusive carbon dioxide flux (F(CO2)) from a hydroelectric reservoir located at Amazon rainforest. Our results showed that for the studied periods (2013 summer/wet and winter/dry seasons) the surface averaged F(CO2) presented similar behaviors, with regular emissions peaks. The mean daily surface averaged F(CO2) showed no significant difference between the seasons (p>0.01), with values around -1338mg Cm-2day-1 (summer/wet) and -1395mg Cm-2day-1 (winter/dry). At diel scale, the F(CO2) was large during the night and morning and low during the afternoon in both seasons. Regarding its spatial distribution, the F(CO2) showed to be more heterogeneous during the summer/wet than during the winter/dry season. The highest F(CO2) were observed at transition zone (-300mg Cm-2h-1) during summer and at littoral zone (-55mg Cm-2h-1) during the winter. The total CO2 emitted by the reservoir along 2013 year was estimated to be 1.1Tg C year-1. By extrapolating our results we found that the total carbon emitted by all Amazonian reservoirs can be around 7Tg C year-1, which is 22% lower than the previous published estimate. This significant difference should not be neglected in the carbon inventories since the carbon emission is a key factor when comparing the environmental impacts of different sources of electricity generation and can influences decision makers in the selection of the more appropriate source of electricity and, in case of hydroelectricity, the geographical position of the reservoirs.

  17. Discontinuities Characteristics of the Upper Jurassic Arab-D Reservoir Equivalent Tight Carbonates Outcrops, Central Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Abdlmutalib, Ammar; Abdullatif, Osman

    2017-04-01

    Jurassic carbonates represent an important part of the Mesozoic petroleum system in the Arabian Peninsula in terms of source rocks, reservoirs, and seals. Jurassic Outcrop equivalents are well exposed in central Saudi Arabia and which allow examining and measuring different scales of geological heterogeneities that are difficult to collect from the subsurface due to limitations of data and techniques. Identifying carbonates Discontinuities characteristics at outcrops might help to understand and predict their properties and behavior in the subsurface. The main objective of this study is to identify the lithofacies and the discontinuities properties of the upper Jurassic carbonates of the Arab D member and the Jubaila Formation (Arab-D reservoir) based on their outcrop equivalent strata in central Saudi Arabia. The sedimentologic analysis revealed several lithofacies types that vary in their thickness, abundances, cyclicity and vertical and lateral stacking patterns. The carbonates lithofacies included mudstone, wackestone, packstone, and grainstone. These lithofacies indicate deposition within tidal flat, skeletal banks and shallow to deep lagoonal paleoenvironmental settings. Field investigations of the outcrops revealed two types of discontinuities within Arab D Member and Upper Jubaila. These are depositional discontinuities and tectonic fractures and which all vary in their orientation, intensity, spacing, aperture and displacements. It seems that both regional and local controls have affected the fracture development within these carbonate rocks. On the regional scale, the fractures seem to be structurally controlled by the Central Arabian Graben System, which affected central Saudi Arabia. While, locally, at the outcrop scale, stratigraphic, depositional and diagenetic controls appear to have influenced the fracture development and intensity. The fracture sets and orientations identified on outcrops show similarity to those fracture sets revealed in the upper

  18. Geochemical relationships of petroleum in Mesozoic reservoirs to carbonate source rocks of Jurassic Smackover Formation, southwestern Alabama

    SciTech Connect

    Claypool, G.E.; Mancini, E.A.

    1989-07-01

    Algal carbonate mudstones of the Jurassic Smackover Formation are the main source rocks for oil and condensate in Mesozoic reservoir rocks in southwestern Alabama. This interpretation is based on geochemical analyses of oils, condensates, and organic matter in selected samples of shale (Norphlet Formation, Haynesville Formation, Trinity Group, Tuscaloosa Group) and carbonate (Smackover Formation) rocks. Potential and probable oil source rocks are present in the Tuscaloosa Group and Smackover Formation, respectively. Extractable organic matter from Smackover carbonates has molecular and isotopic similarities to Jurassic oil. Although the Jurassic oils and condensates in southwestern Alabama have genetic similarities, they show significant compositional variations due to differences in thermal maturity and organic facies/lithofacies. Organic facies reflect different depositional conditions for source rocks in the various basins. The Mississippi Interior Salt basin was characterized by more continuous marine to hypersaline conditions, whereas the Manila and Conecuh embayments periodically had lower salnity and greater input of clastic debris and terrestrial organic matter. Petroleum and organic matter in Jurassic rocks of southwestern Alabama show a range of thermal transformations. The gas content of hydrocarbons in reservoirs increases with increasing depth and temperature. In some reservoirs where the temperature is above 266/degrees/F(130/degrees/C), gas-condensate is enriched in isotopically heavy sulfur, apparently derived from thermochemical reduction of Jurassic evaporite sulfate. This process also resulted in increase H/sub 2/S and CO in the gas, and depletion of saturated hydrocarbons in the condensate liquids.

  19. Modeling and optimizing the design of matrix treatments in carbonate reservoirs with self-diverting acid systems

    NASA Astrophysics Data System (ADS)

    Bulgakova, G. T.; Kharisov, R. Ya; Sharifullin, A. R.; Pestrikov, A. V.

    2015-01-01

    Application of a self-diverting-acid based on viscoelastic surfactant (SDVA) is a promising technology for improving the efficacy of acid treatment in oil and gas-bearing carbonate reservoirs. In this study, we present a mathematical model for assessing SDVA flow and reaction with carbonate rock using the SDVA rheological characteristics. The model calculates the technological parameters for acidizing operations and the prediction of well productivity after acid treatment, in addition to technical and economic optimization of the acidizing process by modeling different acid treatment options with varying volumes, injection rates, process fluids stages and initial economic scenarios.

  20. Carbon dioxide and helium emissions from a reservoir of magmatic gas beneath Mammoth Mountain, California

    USGS Publications Warehouse

    Sorey, M.L.; Evans, William C.; Kennedy, B.M.; Farrar, C.D.; Hainsworth, L.J.; Hausback, B.

    1998-01-01

    Carbon dioxide and helium with isotopic compositions indicative of a magmatic source (??13C = -4.5 to -5???, 3He/4He = 4.5 to 6.7 RA) are discharging at anomalous rates from Mammoth Mountain, on the southwestern rim of the Long Valley caldera in eastern California. The gas is released mainly as diffuse emissions from normal-temperature soils, but some gas issues from steam vents or leaves the mountain dissolved in cold groundwater. The rate of gas discharge increased significantly in 1989 following a 6-month period of persistent earthquake swarms and associated strain and ground deformation that has been attributed to dike emplacement beneath the mountain. An increase in the magmatic component of helium discharging in a steam vent on the north side of Mammoth Mountain, which also began in 1989, has persisted until the present time. Anomalous CO2 discharge from soils first occurred during the winter of 1990 and was followed by observations of several areas of tree kill and/or heavier than normal needlecast the following summer. Subsequent measurements have confirmed that the tree kills are associated with CO2 concentrations of 30-90% in soil gas and gas flow rates of up to 31,000 g m-2 d-1 at the soil surface. Each of the tree-kill areas and one area of CO2 discharge above tree line occurs in close proximity to one or more normal faults, which may provide conduits for gas flow from depth. We estimate that the total diffuse CO2 flux from the mountain is approximately 520 t/d, and that 30-50 t/d of CO2 are dissolved in cold groundwater flowing off the flanks of the mountain. Isotopic and chemical analyses of soil and fumarolic gas demonstrate a remarkable homogeneity in composition, suggesting that the CO2 and associated helium and excess nitrogen may be derived from a common gas reservoir whose source is associated with some combination of magmatic degassing and thermal metamorphism of metasedimentary rocks. Furthermore, N2/Ar ratios and nitrogen isotopic values

  1. Geochemical Impacts of Leaking CO2 from Subsurface Storage Reservoirs to an Unconfined Oxidizing Carbonate Aquifer

    SciTech Connect

    Wang, Guohui; Qafoku, Nikolla; Lawter, Amanda R.; Bowden, Mark E.; Harvey, Omar; Sullivan, E. C.; Brown, Christopher F.

    2015-07-15

    A series of batch and column experiments combined with solid phase characterization studies (i.e., quantitative x-ray diffraction and wet chemical extractions) were conducted to address a variety of scientific issues and evaluate the impacts of the potential leakage of carbon dioxide (CO2) from deep subsurface storage reservoirs. The main objective was to gain an understanding of how CO2 gas influences: 1) the aqueous phase pH; and 2) mobilization of major, minor, and trace elements from minerals present in an aquifer overlying potential CO2 sequestration subsurface repositories. Rocks and slightly weathered rocks representative of an unconfined, oxidizing carbonate aquifer within the continental US, i.e., the Edwards aquifer in Texas, were used in these studies. These materials were exposed to a CO2 gas stream or were leached with a CO2-saturated influent solution to simulate different CO2 gas leakage scenarios, and changes in aqueous phase pH and chemical composition were measured in the liquid samples collected at pre-determined experimental times (batch experiments) or continuously (column experiments). The results from the strong acid extraction tests confirmed that in addition to the usual elements present in most soils, rocks, and sediments, the Edward aquifer samples contain As, Cd, Pb, Cu, and occasionally Zn, which may potentially be mobilized from the solid to the aqueous phase during or after exposure to CO2. The results from the batch and column experiments confirmed the release of major chemical elements into the contacting aqueous phase (such as Ca, Mg, Ba, Sr, Si, Na, and K); the mobilization and possible rapid immobilization of minor elements (such as Fe, Al, and Mn), which are able to form highly reactive secondary phases; and sporadic mobilization of only low concentrations of trace elements (such as As, Cd, Pb, Cu, Zn, Mo, etc.). The results from this experimental research effort will help in developing a systematic understanding of how CO2

  2. Abandoned Texas oil fields

    SciTech Connect

    Not Available

    1980-12-01

    Data for Texas abandoned oil fields were primarily derived from two sources: (1) Texas Railroad Commission (TRRC), and (2) Dwight's ENERGYDATA. For purposes of this report, abandoned oil fields are defined as those fields that had no production during 1977. The TRRC OILMASTER computer tapes were used to identify these abandoned oil fields. The tapes also provided data on formation depth, gravity of oil production, location (both district and county), discovery date, and the cumulative production of the field since its discovery. In all, the computer tapes identified 9211 abandoned fields, most of which had less than 250,000 barrel cumulative production. This report focuses on the 676 abandoned onshore Texas oil fields that had cumulative production of over 250,000 barrels. The Dwight's ENERGYDATA computer tapes provided production histories for approximately two-thirds of the larger fields abandoned in 1966 and thereafter. Fields which ceased production prior to 1966 will show no production history nor abandonment date in this report. The Department of Energy hopes the general availability of these data will catalyze the private sector recovery of this unproduced resource.

  3. Design and implementation of a CO{sub 2} flood utilizing advanced reservoir characterization and horizontal injection wells in a shallow shelf carbonate approaching waterflood depletion

    SciTech Connect

    1996-08-09

    The first objective is to utilize reservoir characterization and advanced technologies to optimize the design of a carbon dioxide (CO{sub 2}) project for the South Cowden Unit (SCU) located in Ector County, Texas. The SCU is a mature, relatively small, shallow shelf carbonate unit nearing, waterflood depletion. The second objective is to demonstrate the performance and economic viability of the project in the field. This report includes work on the reservoir characterization and project design objective and the demonstration project objective.

  4. Quantifying porosity and permeability of fractured carbonates and fault rocks in natural groundwater reservoirs

    NASA Astrophysics Data System (ADS)

    Pirmoradi, Reza; Wolfmayr, Mariella; Bauer, Helene; Decker, Kurt

    2017-04-01

    This study presents porosity and permeability data for a suite of different carbonate rocks from two major groundwater reservoirs in eastern Austria that supply more than 60% of Vienna`s drinking water. Data includes a set of lithologically different, unfractured host rocks, fractured rocks with variable fracture intensities, and fault rocks such as dilation breccias, different cataclasites and dissolution-precipitation fault rocks. Fault rock properties are of particular importance, since fault zones play an important role in the hydrogeology of the reservoirs. The reservoir rocks are exposed at two major alpine karst plateaus in the Northern Calcareous Alps. They comprise of various Triassic calcareous strata of more than 2 km total thickness that reflect facies differentiation since Anisian times. Rocks are multiply deformed resulting in a partly dense network of fractures and faults. Faults differ in scale, fault rock content, and fault rock volumes. Methods used to quantify the porosity and permeability of samples include a standard industry procedure that uses the weight of water saturated samples under hydrostatic uplift and in air to determine the total effective (matrix and fracture) porosity of rocks, measurements on plugs with a fully automated gas porosity- and permeameter using N2 gas infiltrating plugs under a defined confining pressure (Coreval Poro 700 by Vinci technologies), and percolation tests. The latter were conducted in the field along well known fault zones in order to test the differences in fractured rock permeability in situ and on a representative volume, which is not ensured with plug measurements. To calculate hydraulic conductivity by the Darcy equation the measured elapsed time for infiltrating a standard volume of water into a small borehole has been used. In general, undisturbed host rock samples are all of low porosity (average around 1%). The open porosity of the undisturbed rocks belonging to diverse formations vary from 0

  5. Geoscience/Engineering Characterization of the Interwell Environment in Carbonate Reservoirs Based on Outcrop Analogs, Permian Basin, West Texas and New Mexico.

    SciTech Connect

    Lucia, F.J.; Kerans, C.

    1996-12-31

    The objective of this project is to investigate styles of reservoir heterogeneity found in low permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study.

  6. Cost Effective Surfactant Formulations for Improved Oil Recovery in Carbonate Reservoirs

    SciTech Connect

    William A. Goddard; Yongchun Tang; Patrick Shuler; Mario Blanco; Yongfu Wu

    2007-09-30

    This report summarizes work during the 30 month time period of this project. This was planned originally for 3-years duration, but due to its financial limitations, DOE halted funding after 2 years. The California Institute of Technology continued working on this project for an additional 6 months based on a no-cost extension granted by DOE. The objective of this project is to improve the performance of aqueous phase formulations that are designed to increase oil recovery from fractured, oil-wet carbonate reservoir rock. This process works by increasing the rate and extent of aqueous phase imbibition into the matrix blocks in the reservoir and thereby displacing crude oil normally not recovered in a conventional waterflood operation. The project had three major components: (1) developing methods for the rapid screening of surfactant formulations towards identifying candidates suitable for more detailed evaluation, (2) more fundamental studies to relate the chemical structure of acid components of an oil and surfactants in aqueous solution as relates to their tendency to wet a carbonate surface by oil or water, and (3) a more applied study where aqueous solutions of different commercial surfactants are examined for their ability to recover a West Texas crude oil from a limestone core via an imbibition process. The first item, regarding rapid screening methods for suitable surfactants has been summarized as a Topical Report. One promising surfactant screening protocol is based on the ability of a surfactant solution to remove aged crude oil that coats a clear calcite crystal (Iceland Spar). Good surfactant candidate solutions remove the most oil the quickest from the surface of these chips, plus change the apparent contact angle of the remaining oil droplets on the surface that thereby indicate increased water-wetting. The other fast surfactant screening method is based on the flotation behavior of powdered calcite in water. In this test protocol, first the calcite

  7. Co-assessment of biomass and soil organic carbon stocks in a future reservoir area located in Southeast Asia.

    PubMed

    Descloux, Stéphane; Chanudet, Vincent; Poilvé, Hervé; Grégoire, Alain

    2011-02-01

    An assessment of the organic carbon stock present in living or dead vegetation and in the soil on the 450 km2 of the future Nam Theun 2 hydroelectric reservoir in Lao People's Democratic Republic was made. Nine land cover types were defined on the studied area: dense, medium, light, degraded, and riparian forests; agricultural soil; swamps; water; and others (roads, construction sites, and so on). Their geographical distribution was assessed by remote sensing using two 2008 SPOT 5 images. The area is mainly covered by dense and light forests (59%), while agricultural soil and swamps account for 11% and 2%, respectively. For each of these cover types, except water, organic carbon density was measured in the five pools defined by the Intergovernmental Panel on Climate Change: aboveground biomass, litter, deadwood, belowground biomass, and soil organic carbon. The area-weighted mean carbon densities for these pools were estimated at 45.4, 2.0, 2.2, 3.4, and 62.2 tC/ha, respectively, i.e., a total of about 115±15 tC/ha for a soil thickness of 30 cm, corresponding to a total flooded organic carbon stock of 5.1±0.7 MtC. This value is much lower than the carbon density for some South American reservoirs for example where total organic carbon stocks range from 251 to 326 tC/ha. It can be mainly explained by (1) the higher biomass density of South American tropical primary rainforest than of forests in this study and (2) the high proportion of areas with low carbon density, such as agricultural or slash-and-burn zones, in the studied area.

  8. Karst-controlled reservoir heterogeneity in Ellenburger group carbonates of west Texas: Reply

    SciTech Connect

    Kerans, C. )

    1990-07-01

    A reply to a comment made on Kerans' paper (AAGP Bull. 1988) by S.J. Mazzullo is presented. The author takes exception that Mazzullo's contention that he left out important types of hydrocarbon reservoirs in the Permian basin of west Texas and points out that his original intention was to model karst-controlled reservoir rocks only.

  9. Sedimentary record of water column trophic conditions and sediment carbon fluxes in a tropical water reservoir (Valle de Bravo, Mexico).

    PubMed

    Carnero-Bravo, Vladislav; Merino-Ibarra, Martín; Ruiz-Fernández, Ana Carolina; Sanchez-Cabeza, Joan Albert; Ghaleb, Bassam

    2015-03-01

    Valle de Bravo (VB) is the main water reservoir of the Cutzamala hydraulic system, which provides 40% of the drinking water consumed in the Mexico City Metropolitan Area and exhibits symptoms of eutrophication. Nutrient (C, N and P) concentrations were determined in two sediment cores to reconstruct the water column trophic evolution of the reservoir and C fluxes since its creation in 1947. Radiometric methods ((210)Pb and (137)Cs) were used to obtain sediment chronologies, using the presence of pre-reservoir soil layers in one of the cores as an independent chronological marker. Mass accumulation rates ranged from 0.12 to 0.56 g cm(-2) year(-1) and total organic carbon (TOC) fluxes from 122 to 380 g m(-2) year(-1). Total N ranged 4.9-48 g m(-2) year(-1), and total P 0.6-4.2 g m(-2) year(-1). The sedimentary record shows that all three (C, N and P) fluxes increased significantly after 1991, in good agreement with the assessed trophic evolution of VB and with historic and recent real-time measurements. In the recent years (1992-2006), the TOC flux to the bottom of VB (average 250 g m(-2) year(-1), peaks 323 g m(-2) year(-1)) is similar to that found in highly eutrophic reservoirs and impoundments. Over 1/3 of the total C burial since dam construction, circa 70,000 t, has occurred in this recent period. These results highlight the usefulness of the reconstruction of carbon and nutrient fluxes from the sedimentary record to assess carbon burial and its temporal evolution in freshwater ecosystems.

  10. Diffusive emission of methane and carbon dioxide from two hydropower reservoirs in Brazil.

    PubMed

    Marcelino, A A; Santos, M A; Xavier, V L; Bezerra, C S; Silva, C R O; Amorim, M A; Rodrigues, R P; Rogerio, J P

    2015-05-01

    The role of greenhouse gas emissions from freshwater reservoirs and their contribution to increase greenhouse gas concentrations in the atmosphere is currently under discussion in many parts of the world. We studied CO2 and CH4 diffusive fluxes from two large neotropical hydropower reservoirs with different climate conditions. We used floating closed-chambers to estimate diffusive fluxes of these gaseous species. Sampling campaigns showed that the reservoirs studied were sources of greenhouse gases to the atmosphere. In the Serra da Mesa Reservoir, the CH4 emissions ranged from 0.530 to 396.96 mg.m(-2).d(-1) and CO2 emissions ranged from -1,738.33 to 11,166.61 mg.m(-2).d(-1) and in Três Marias Reservoir the CH4 fluxes ranged 0.720 to 2,578.03 mg.m(-2).d(-1) and CO2 emission ranged from -3,037.80 to 11,516.64 to mg.m(-2).d(-1). There were no statistically significant differences of CH4 fluxes between the reservoirs, but CO2 fluxes from the two reservoirs studied were significantly different. The CO2 emissions measured over the periods studied in Serra da Mesa showed some seasonality with distinctions between the wet and dry transition season. In Três Marias Reservoir the CO2 fluxes showed no seasonal variability. In both reservoirs, CH4 emissions showed a tendency to increase during the study periods but this was not statistically significant. These results contributed to increase knowledge about the magnitude of CO2 and CH4 emission in hydroelectric reservoirs, however due to natural variability of the data future sampling campaigns will be needed to better elucidate the seasonal influences on the fluxes of greenhouse gases.

  11. Subtask 1.17 - Measurement of Hydrocarbon Evolution from Coal and Petroleum Reservoirs Under Carbon Dioxide Floods

    SciTech Connect

    Steven B. Hawthorne

    2006-12-31

    The project developed, built, and tested three apparatuses for studying different interactions of carbon dioxide with geologic materials. In Year 1, an online instrument was constructed by coupling a high-pressure carbon dioxide extraction system with a flame ionization detector that can yield a real-time profile and quantitative measurements of hydrocarbons removed from materials such as coal and petroleum reservoir rock. In Years 2 and 3, one instrument was built to measure the excess sorption of carbon dioxide in geologic materials such as coal and showed that measurable uptake of carbon dioxide into the coal matrix is rapid. The final apparatus was built to expose geologic materials to carbon dioxide for long periods of time (weeks to months) under the range of pressures and temperatures relevant to carbon dioxide sequestration. The apparatus allows as many as twenty gram-sized samples of geologic materials to be exposed simultaneously and can also include exposures with geologic brines. The system was used to demonstrate complete conversion of magnesium silicate to magnesium carbonate in less than 4 weeks when exposed to clean water or brine, compared to no measurable conversion of dry magnesium carbonate.

  12. Abandoned Mine Lands

    EPA Pesticide Factsheets

    Abandoned Mine Lands are those lands, waters, and surrounding watersheds where extraction, beneficiation, or processing of ores and minerals (excluding coal) has occurred. These lands also include areas where mining or processing activity is inactive.

  13. Influence of the timing of HC injection on the preservation of petrophysical properties of carbonate reservoirs at great depth

    NASA Astrophysics Data System (ADS)

    Neveux, Lucille; Grgic, Dragan; Pironon, Jacques; Carpentier, Cédric; Girard, Jean-Pierre

    2013-04-01

    In the oil industry, the preservation of petrophysical properties at great depth may lead to the existence of a deeply buried reservoir (DBR), a favoured target in the field of petroleum exploration and exploitation. The accurate prediction of reservoir quality requires an understanding of the key controlling diagenetic processes. Pressure solution is one of the main processes happening during diagenesis and being responsible for the evolution of porosity and permeability in many reservoirs. However, others processes may potentially act upon carbonate rocks during diagenesis: the timing of oil arrival is one of these processes. The aim of this study is to investigate experimentally the influence of oil injection and timing of this injection on the pressure solution process and thus on carbonate petrophysical properties. The experiments were performed using a subsurface consolidated carbonate rock and a specifically designed experimental apparatus, enabling the simulation of in situ conditions (pressure/stresses and temperature) of deeply buried reservoirs. Three experiments were realised with different fluids and injection conditions, namely meteoric fluid as the interstitial fluid, early saturation in oil of the sample followed by the injection of a meteoric fluid, late injection of oil in a sample initially saturated with a meteoric fluid. The results obtained in this study showed that without oil in the interstitial fluid, the main diagenetic process is the pressure solution creep (PSC). This process reduces by three the initial porosity but don't have any significant influence on permeability. When the sample was initially saturated with oil before the injection of the meteoric fluid, the process of PSC was inhibited. In this case, the porosity showed a slight decrease and the permeability showed a strong decrease from 23 mD to 1 mD. When an initially saturated (with a meteoric fluid) sample undergone a late injection of oil, the porosity was not preserved and

  14. INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO

    SciTech Connect

    Ernest A. Mancini

    2001-09-14

    The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling which utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 1 of the project has been reservoir description and characterization. This effort has included four tasks: (1) geoscientific reservoir characterization, (2) the study of rock-fluid interactions, (3) petrophysical and engineering characterization and (4) data integration. This work was scheduled for completion in Year 1. Overall, the project work is on schedule. Geoscientific reservoir characterization is essentially completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions has been initiated. Observations regarding the diagenetic processes influencing pore system development and heterogeneity in these reef and shoal reservoirs have been

  15. INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO

    SciTech Connect

    Ernest A. Mancini

    2002-09-25

    The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling which utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 2 of the project has been reservoir characterization, 3-D modeling and technology transfer. This effort has included six tasks: (1) the study of rockfluid interactions, (2) petrophysical and engineering characterization, (3) data integration, (4) 3-D geologic modeling, (5) 3-D reservoir simulation and (6) technology transfer. This work was scheduled for completion in Year 2. Overall, the project work is on schedule. Geoscientific reservoir characterization is essentially completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions is near completion. Observations regarding the diagenetic processes influencing pore system development and

  16. Abandoning wells working group

    SciTech Connect

    1997-03-01

    The primary objective of this working group is to identify major technical, regulatory, and environmental issues that are relevant to the abandonment of offshore wellbores. Once the issues have been identified, the working group also has the objective of making recommendations or providing potential solutions for consideration. Areas for process improvement will be identified and {open_quotes}best practices{close_quotes} will be discussed and compared to {open_quotes}minimum standards.{close_quotes} The working group will primarily focus on wellbore abandonment in the Gulf of Mexico. However, workshop participants are encouraged to discuss international issues which may be relevant to wellbore abandonment practices in the Gulf of Mexico. The Abandoning Wells Group has identified several major areas for discussion that have concerns related to both operators and service companies performing wellbore abandonments in the Gulf of Mexico. The following broad topics were selected for the agenda: (1) MMS minimum requirements and state regulations. (2) Co-existence of best practices, new technology, and P & A economics. (3) Liability and environmental issues relating to wellbore abandonment.

  17. Spatial Risk Analysis of Hydraulic Fracturing near Abandoned and Converted Oil and Gas Wells.

    PubMed

    Brownlow, Joshua W; Yelderman, Joe C; James, Scott C

    2017-03-01

    Interaction between hydraulically generated fractures and existing wells (frac hits) could represent a potential risk to groundwater. In particular, frac hits on abandoned oil and gas wells could lead to upward leakage into overlying aquifers, provided migration pathways are present along the abandoned well. However, potential risk to groundwater is relatively unknown because few studies have investigated the probability of frac hits on abandoned wells. In this study, actual numbers of frac hits were not determined. Rather, the probability for abandoned wells to intersect hypothetical stimulated reservoir sizes of horizontal wells was investigated. Well data were compiled and analyzed for location and reservoir information, and sensitivity analyses were conducted by varying assumed sizes of stimulated reservoirs. This study used public and industry data for the Eagle Ford Shale play in south Texas, with specific attention paid to abandoned oil and gas wells converted into water wells (converted wells). In counties with Eagle Ford Shale activity, well-data analysis identified 55,720 abandoned wells with a median age of 1983, and 2400 converted wells with a median age of 1954. The most aggressive scenario resulted in 823 abandoned wells and 184 converted wells intersecting the largest assumed stimulated reservoir size. Analysis showed abandoned wells have the potential to be intersected by multiple stimulated reservoirs, and risks for intersection would increase if currently permitted horizontal wells in the Eagle Ford Shale are actually completed. Results underscore the need to evaluate historical oil and gas activities in areas with modern unconventional oil and gas activities.

  18. Improved oil recovery in Mississippian carbonate reservoirs of Kansas near term Class 2. Annual report, September 18, 1994--March 15, 1997

    SciTech Connect

    Carr, T.R.; Green, D.W.; Willhite, G.P.

    1998-04-01

    This annual report describes progress during the second year of the project entitled {open_quotes}Improved Oil Recovery in Mississippian Carbonate Reservoirs in Kansas{close_quotes}. This project funded under the Department of Energy`s Class 2 program targets improving the reservoir performance of mature oil fields located in shallow shelf carbonate reservoirs. The focus of this project is development and demonstration of cost-effective reservoir description and management technologies to extend the economic life of mature reservoirs in Kansas and the mid-continent. As part of the project, several tools and techniques for reservoir description and management were developed, modified and demonstrated. These include: (1) a new approach to subsurface visualization using electric logs ({open_quotes}Pseudoseismic{open_quotes}); (2) a low-cost easy-to-use spreadsheet log analysis software (PfEFFER); and (3) an extension of the BOAST-3 computer program for full field reservoir simulation. The world-wide-web was used to provide rapid and flexible dissemination of the project results through the Internet. Included in this report is a summary of significant project results at the demonstration site (Schaben Field, Ness County, Kansas). These results include an outline of the reservoir description based on available and newly acquired data and reservoir simulation results. Detailed information is available on-line through the Internet. Based on the reservoir simulation, three infill wells will be drilled to validate the reservoir description and demonstrate the effectiveness of the proposed reservoir management strategies. The demonstration phase of the project has just begun and will be presented in the next annual report.

  19. Fish mercury development in relation to abiotic characteristics and carbon sources in a six-year-old, Brazilian reservoir.

    PubMed

    Tuomola, Leena; Niklasson, Terese; de Castro E Silva, Edinaldo; Hylander, Lars D

    2008-02-01

    Time series on fish mercury (Hg) development are rare for hydroelectric reservoirs in the tropics. In the central-western part of Brazil, a hydroelectric reservoir, called Lago Manso, was completed in 1999 after that background levels of fish Hg concentrations had been determined. The development for the first 3 years was studied in 2002. The objective of the present study was to determine development of fish Hg concentrations for a second three-year period after flooding. The bioaccumulation factor and certain abiotic and biotic factors, possibly affecting the availability and accumulation of Hg, were also examined. The results show that Hg levels in fish from Lago Manso have increased more than five times compared to the background levels observed before construction of the reservoir. At the same time, dissolved organic carbon has increased while dissolved oxygen has decreased indicating enhanced bioavailability of Hg. In the reservoir, Salminus brasiliensis had in average a Hg content of 1.1 microg g(-1) f.w., Pseudoplatystoma fasciatum 1.2, Serrasalmus marginatus/spilopleura 0.9, and Brycon hilarii 0.6 microg g(-1) f.w. The average fish Hg contents were higher downstream, except for B. hilarii. In the reservoir, the average Hg content of each species was in 2005 always over the consumption limit (0.55 microg total Hg g(-1) f.w.) recommended by WHO. Therefore, the people living around Lago Manso should be informed of the health effects of Hg, and fish consumption recommendations should be carried out. The accumulation of Hg varies widely between species as shown by the bioaccumulation factor which ranges between 5.08 and 5.59 log units. The observed variation is explained by differences in diet and trophic position with piscivorous fish exhibiting the highest mean Hg concentration, followed by carnivorous and omnivorous species. Carbon isotope analyses imply that trophic position is not the only cause of the observed differences in Hg levels between omnivorous B

  20. Ranking of Texas reservoirs for application of carbon dioxide miscible displacement

    SciTech Connect

    Ham, J

    1996-04-01

    Of the 431 reservoirs screened, 211 projected revenue that exceeded cost, ie, were profitable. Only the top 154 reservoirs, however, showed a profit greater than 30%. The top 10 reservoirs predicted a profit of at least 80%. Six of the top ten were Gulf Coast sandstones. The reservoirs are representative of the most productive discoveries in Texas; they account for about 72% of the recorded 52 billion barrels oil production in the State. Preliminary evaluation in this study implied that potential production from CO{sub 2}-EOR could be as much as 4 billion barrels. In order to enhance the chances of achieving this, DOE should consider a targeted outreach program to the specific independent operators controlling the leases. Development of ownership/technical potential maps and an outreach program should be initiated to aid this identification.

  1. Carbonate-platform scale correlation of stacked high-frequency sequences in the Arab-D reservoir, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Al-Awwad, Saad F.; Collins, Lindsay B.

    2013-08-01

    The Late Jurassic Arab Formation contains a number of hydrocarbon-bearing carbonates, the most important of which is the lowermost Arab-D reservoir. The reservoir lithofacies in Khurais Field are: couplets of 1) lime mud and 2) intraclastic lithofacies representing basinal turbidites; 3) pelletal lithofacies representing lower shoreface sands and silts; 4) stromatoporoid lithofacies representing a reef; 5) Cladocoropsis and 6) dasyclad lithofacies representing a lagoon; 7) peloidal and 8) oolitic lithofacies representing shore-attached sand sheets; 9) cryptomicrobial lithofacies representing supratidal flats; 10) anhydrites representing sabkha followed by salina deposits; and 11) stratigraphically reoccurring dolomite. These are arranged in two, partially preserved, third-order sequences, the upper of which represents the Arab-D Member and the lower of which represents the upper Jubaila Formation. Within these sequences lie six fourth-order high frequency sequences, composed of fifth-order parasequences and parasequence-scale cycles. The preserved upward shallowing trend of the Arab-D reservoir is manifested laterally by a regional eastward thickening interpreted to be the result of an eastward progradation across the shallow Late Jurassic epeiric shelf and into the relatively deep Arabian intrashelf basin. This study presents a correlation model that explains the drastic thickening and downward climb of the reservoir lithofacies that is observed between the outcrops south of Riyadh and the subsurface in Ghawar Field. This model is different from the one currently used and predicts an eastward porosity improvement in the upper part of the reservoir accompanied by a porosity reduction in the lower part, assuming a null diagenetic modification effect.

  2. Methane and carbon dioxide production in soils flooded by the Belo Monte hydropower reservoir in the Amazon Basin, Brazil

    NASA Astrophysics Data System (ADS)

    Sawakuchi, H. O.; Bertassoli, D. J., Jr.; Silveira, A. M.; Bozi, B. S.; de Jesus, J. S.; Sawakuchi, A. O.; Ward, N. D.; Bastviken, D.; Krusche, A. V.; Richey, J. E.

    2016-12-01

    The Xingu River, one of the major tributary of the Amazon River, was recently impounded by the Belo Monte dam, a massive and controversial hydropower plant that will become the third biggest power station in generating capacity of the world. Given the limited data associated with greenhouse gas emissions from reservoirs in the Amazon basin, the impacts of hydroelectric expansion in this region to the global carbon budget remains unclear. Here, we used a bottom-up assessment to quantify a fraction of the possible emissions associated with the Belo Monte reservoir. Eighteen soil samples were collected before the impoundment from seven different locations and depths in areas that were going to be permanently flooded by the reservoir (forests and pasturelands). Soil samples were split in triplicates and incubated in anoxic conditions during two phases totaling 160 days of anoxic incubation in order to quantify the potential methane and carbon dioxide production through time. Our results showed that pasturelands soil presented higher potential production of both gases in relation to the soils from forested areas, reaching up to 0.072 mg CH4 g-¹d-1 and 0.078 mg CO2 g-¹d-1 during the first period of 65 days in the first phase of incubations. Significant differences in production were also noted through soil depth and time. In several areas, the first 15 cm of soil generated 99% of the methane volume that was being produced in the 60 cm sampled profile. The first 65 days of the second phase of incubations showed production that was 35% (CH4) and 44% (CO2) lower than the same period in the first stage. Extrapolations towards the total flooded area demonstrates that 27.3-43.3 ton CH4 d-1 may be generated from flooded soils in the Belo Monte reservoir during only the first several months of flooding, maintaining significant production rates during upcoming months as long as favorable conditions are maintained.

  3. Carbon dioxide and helium emissions from a reservoir of magmatic gas beneath Mammoth Mountain, California

    SciTech Connect

    Sorey, M.L.; Evans, W.C. Kennedy, B.M. Farrar, C.D. Hainsworth, L.J. Hausback, B.

    1998-07-01

    Carbon dioxide and helium with isotopic compositions indicative of a magmatic source ({delta}thinsp{sup 13}C={minus}4.5 to {minus}5{per_thousand}, {sup 3}He/{sup 4}He=4.5 to 6.7 R{sub A}) are discharging at anomalous rates from Mammoth Mountain, on the southwestern rim of the Long Valley caldera in eastern California. The gas is released mainly as diffuse emissions from normal-temperature soils, but some gas issues from steam vents or leaves the mountain dissolved in cold groundwater. The rate of gas discharge increased significantly in 1989 following a 6-month period of persistent earthquake swarms and associated strain and ground deformation that has been attributed to dike emplacement beneath the mountain. An increase in the magmatic component of helium discharging in a steam vent on the north side of Mammoth Mountain, which also began in 1989, has persisted until the present time. Anomalous CO{sub 2} discharge from soils first occurred during the winter of 1990 and was followed by observations of several areas of tree kill and/or heavier than normal needlecast the following summer. Subsequent measurements have confirmed that the tree kills arc associated with CO{sub 2} concentrations of 30{endash}90{percent} in soil gas and gas flow rates of up to 31,000 gthinspm{sup {minus}2}thinspd{sup {minus}1} at the soil surface. Each of the tree-kill areas and one area of CO{sub 2} discharge above tree line occurs in close proximity to one or more normal faults, which may provide conduits for gas flow from depth. We estimate that the total diffuse CO{sub 2} flux from the mountain is approximately 520 t/d, and that 30{endash}50 t/d of CO{sub 2} are dissolved in cold groundwater flowing off the flanks of the mountain. Isotopic and chemical analyses of soil and fumarolic gas demonstrate a remarkable homogeneity in composition, suggesting that the CO{sub 2} and associated helium and excess nitrogen may be derived from a common gas reservoir whose source is associated with

  4. MULTIDISCIPLINARY IMAGING OF ROCK PROPERTIES IN CARBONATE RESERVOIRS FOR FLOW-UNIT TARGETING

    SciTech Connect

    Stephen C. Ruppel

    2004-07-20

    Our analysis and imaging of reservoir properties at the Fullerton Clear Fork field (Figure 1) is in its final stages. Major accomplishments during the past 6 months include: (1) characterization of facies and cyclicity in cores, (2) correlation of cycles and sequences using core-calibrated wireline logs, (3) calculation and modeling of wireline porosity, (4) analysis of new cores for conventional and special core analysis data, (5) construction of full-field reservoir model, and (6) revision of 3D seismic inversion of reservoir porosity and permeability. One activity has been eliminated from the originally proposed tasks. Task 3 (Characterization and Modeling of Rock Mechanics and Fractures) has been deleted because we have determined that fractures are not significant contributing in the reservoir under study. A second project extension has been asked for to extend the project until 7/31/04. Remaining project activities are: (1) interpretation and synthesis of fieldwide data, (2) preparation of 3D virtual reality demonstrations of reservoir model and attributes, (3) transfer of working data sets to the operator for reservoir implementation and decision-making, and (4) preparation and distribution of final reports.

  5. Stable carbon isotope as a proxy for the change of phytoplankton community structure in cascade reservoirs from Wujiang River, China

    NASA Astrophysics Data System (ADS)

    Wang, B.; Liu, C. Q.; Peng, X.; Wang, F.; Chen, C.

    2011-01-01

    Phytoplankton community structure and δ13C of dissolved inorganic carbon (DIC), particulate organic carbon (POC), and phytoplanktonic carbon (PPC), and the related hydro-chemical parameters have been seasonally investigated in the cascade reservoirs from the Wujiang River Basin. Average values of δ13CDIC, δ13CPOC and δ13CPPC were -8.1±1.3‰, -29.6±2.8‰, and -30.9±4.5‰, respectively. Seasonal fluctuation of δ13CPPC was comparable to that of δ13CPOC and larger than that of δ13CDIC. The δ13CPPC values showed a significant linear correlation with δ13CPOC, indicating that endogenetic phytoplankton is the main source of POC in these cascade reservoirs. Compared to environmental factors such as temperature, taxonomic differences are the main factor influencing δ13CPPC in this study. As a result, the contribution of Bacillariophyta to the total phytoplankton showed a significant negative correlation with δ13CPPC and Δδ13C (δ13CPPC-δ13CDIC), respectively, suggesting that δ13CPPC can be used to discern the change of phytoplankton community structure although only two kinds of dominant algae (i.e. Bacillariophyta and Chlorophyta) facilitate achieving this relationship. This relationship will have an important significance in understanding evolvement of phytoplankton community structure with time using geochemical technique once it is confirmed at a larger scale in field study.

  6. Carbonate reservoir characterization using seismic velocity and amplitude variation with offset analysis: Hardeman basin, Texas, test case

    SciTech Connect

    Pigott, J.D.; Shrestha, R.K. ); Warwick, R.A. )

    1991-03-01

    Mississippian bioherms in the Hardeman basin, Texas, produce from dolomitized mud cores with porosities that can vary from 10 to 40%. These carbonate buildups, though often similar in seismic reflector boundary configuration, can vary remarkably in reservoir quality (e.g., porosity) owing to diagenesis. However, imaging these lateral variations of porosity and determining the reservoir pressure is possible with detailed seismic velocity control and amplitude variation with offset (AVO) analysis. The investigated 24-fold seismic profile was acquired by four Vibroseis trucks in the Hardeman basin across two bioherms, one oil-productive and other tight and water-filled. Detailed stacking velocity analyses on the relative amplitude processed line directly delineate areas of increasing and decreasing gross porosity and dramatically differentiate the two mounds. Moreover, the detailed velocity analyses help provide a more accurate stacked section with resultant better definition of the external mound configuration. Analysis of available laboratory compressional and shear wave velocity data for carbonate rocks reveal that Young's modulus in carbonates is a function of porosity and differential pressure. Comparison of the derived Young's modulus from an inversion of the AVO data for the unstacked line with the experimental laboratory data yield porosity and differential pressure estimates over the productive bioherm which are within 18% and 15%, respectively, of those observed in the borehole.

  7. A neglected - but not negligible - carbon reservoir in the Italian forests: relic charcoal kiln soils.

    NASA Astrophysics Data System (ADS)

    Mastrolonardo, Giovanni; Francioso, Ornella; Carrari, Elisa; Brogi, Cristiana; Venturi, Martina; Certini, Giacomo

    2017-04-01

    Charcoal production in forests is one of the oldest human activities in Italy and the other European countries. Here, 3 thousand years ago civilizations were already used to convert wood into charcoal for energetic and metallurgic purposes. The technique for making charcoal remained substantially unchanged in time: wood piles covered with turf were built in appositely shaped emplacements, and then left to pyrolyse for days under controlled semi-anoxic conditions. This widespread activity lasted until a few decades ago, leaving as legacy a plethora of repeatedly used emplacements where soil shows a thick top layer very rich in charcoal. Despite the high frequency of relic charcoal kilns in the European forests, no studies aimed at accurately determining their C stock to assess their relevance as C sink in forest environment. In this work, we studied some relic charcoal kilns in a mixed oak forest at Marsiliana, Tuscany, central Italy, where charcoal production was enduring and massive at least since the Middle age. At Marsiliana, density of charcoal kiln sites was not uniform within the forest areas as it mostly depends on biomass availability. According to the aspect, northerly or southerly, we recognized two main forest areas where kiln sites density ranged between 2 and 3 sites per hectare. In general, the C content in the kiln soils was eight times the one in the surrounding soil, with just one third of the C in the form of pyrogenic C. Hence, natural organic carbon content was significantly higher in the kiln soils. Such a finding confirms that charcoal gives a substantial contribution to the C stock in the kilns but does not fully account for their particular richness in C. It has been thus hypothesized that charcoal is somehow able to stimulate the accumulation of native soil organic matter. At Marsiliana forest, relic charcoal kilns soils cover less than 0.5% of total surface. Nonetheless, their contribution to the total C stock in the top soil (30 cm

  8. Integration of Well & Core Data of Carbonate Reservoirs with Surface Seismic in Garraf Oil Field, Southern Iraq

    NASA Astrophysics Data System (ADS)

    Mhuder, J. J.; Muhlhl, A. A.; Basra Geologiests

    2013-05-01

    The Garraf Field is situated in Southern Iraq in Nasiriya area, is located in Mesopotamian basin. The carbonate facies are dominant in main reservoirs in Garraf field (Mishrif and Yammama Formations) which is Cretaceous in age. The structure of the reservoir in this field are low relief gentle anticlinal structure aligned in NW to SE direction, and No fault were observed and interpreted in 3D seismic section. 3D seismic survey by Iraqi Oil Exploration Company No 2 was successfully conducted on the Garraf field at 2008-2009 using recording system SERCEL 408UL and Vibrators Nomad 65. Bin size: 25*25, Fold: 36, SP Interval: 50m, Lines Interval: 300m, 3 wells were drilled Ga (1, 2, 3) and it used for seismic to well tie in Petrel. Data analysis was conducted for each reservoirs for Lithological and sedimentological studies were based on core and well data .The study showed That the Mishrif Formation deposited in a broad carbonate platform with shallowing upward regressive succession and The depositional environment is extending from outer marine to shallow middle-inner shelf settings with restricted lagoons as supported by the present of Miliolid fossils. The fragmented rudist biostromes accumulated in the middle shelf. No rudist reef is presence in the studied cores. While the Major sequences are micritic limestone of lagoonal and oolitic/peloidal grainstone sandy shoal separated by mudstone of Yamama formation. Sedimentation feature are seen on seismic attributes and it is help for understanding of sedimentation environment and suitable structure interpretation. There is good relationship between Acustic Impedance and porosity, Acustic Impedance reflects porosity or facies change of carbonate rather than fluid content. Data input used for 3D Modeling include 3D seismic and AI data, petrophysical analysis, core and thin section description. 3D structure modeling were created base on the geophysical data interpretation and Al analysis. Data analysis for Al data were

  9. [Effects of biological regulated measures on active organic carbon and erosion-resistance in the Three Gorges Reservoir region soil].

    PubMed

    Huang, Ru; Huang, Lin; He, Bing-Hui; Zhou, Li-Jiang; Yu, Chuan; Wang, Feng

    2013-07-01

    To gain a better knowledge of characteristics of soils and provide a scientific basis for soil erosion control in the Three Gorges Reservoir Area, contents of aggregates and total soil organic carbon (SOC), as well as soil active organic carbon fractions including particulate organic carbon (POC), readily oxidized organic carbon (ROC), dissolved organic carbon (DOC), microbial biomass carbon (MBC) in the 0-30 cm soil layer under seven different biological regulated measures were studied by the field investigation combined with the laboratory analysis. Results showed that the content of the SOC and active organic carbon fractions decreased with the increasing soil depth; the content of the SOC and active organic carbon fractions in 0-10 cm was significantly higher than that in 20-30 cm. The stability of soil aggregates were also significantly influenced by biological regulated measures, the content of > 0.25 mm water-stable aggregates in seven types of biological regulated measures was in the order of Koelreuteria bipinnata + Cassia suffruticasa > hedgerows > closed forest > natural restoration > economic forest > traditional planting > control plot, moreover, the content of 0.25 mm water-stable aggregates correlated positively with the content of SOC. Soils under different biological regulated measures all demonstrated fractal features, and soil under the measure of Koelreuteria bipinnata + Cassia suffruticasa was found to have the lowest value of fractal dimension and soil erodiable K, indicating a relatively strong structure stability and erosion-resistant capacity. Negative correlation was observed when compared the content of active organic carbon fractions with the soil erodiable K. It can be concluded that properties of soil can be managed through biological regulated measures; thence had an influence on the soil erosion-resistant capacity.

  10. [Diffusion flux of partial pressure of dissolved carbon dioxide in Wan'an reservoir in spring].

    PubMed

    Mei, Hang-Yuan; Wang, Fu-Shun; Yao, Chen-Chen; Wang, Bao-Li

    2011-01-01

    In order to understand the emission of greenhouse gases (CO2) from the river-type reservoir, this study investigated the partial pressure of CO2 [p(CO2)], in the surface water, inflow waters, outflow waters of the Wan'an reservoir in China in the May 2009. p(CO2) in the inflow water, outflow water were calculated from titration method, and the surface water p(CO2) was measured underway using a continuous measurement system (equilibrator-NDIR system). Results showed that the inflow water from the Zhangshui, Meijiang, Taojiang have higher p(CO2) than atmosphere level, with the values of 211.5, 91.7, 259.7 Pa respectively. p(CO2) in the surface water of the incoming section of Wan'an reservoir was between 180-210 Pa, and in the middle section and central section near the dam, p(CO2) in the surface water were about 140-180 Pa and 70-110 Pa. In the outflow waters, p(CO2) reached to 176.2 Pa, higher than that in central section. As a result, it can be concluded that the surface water, inflow waters, outflow waters in the Wan'an reservoir are all the source to CO2. However there is clear evidence showing that the reservoir indeed has a role in mitigating the CO2 emission in this case.

  11. Keys to evaluating {open_quotes}paleokarst{close_quotes} reservoirs - guidelines from Quaternary carbonates and enhanced petrography

    SciTech Connect

    Dravis, J.J.

    1996-12-31

    Paleokarst is often invoked to explain reservoir development in ancient brecciated carbonates. However, the paleokarst model is valid only when fabrics seen in Quaternary cave systems are present and petrography of the non-brecciated zones supports subaerial exposure. Quaternary caves typically exhibit early fractures, microscopic to cavernous secondary porosity, solution collapse and brecciation, cave cements, and reddish-brown cave fill. Inter-cavern rocks show fabric-selective dissolution, porosity inversion, precompaction cements, and capping laminated soil crusts. In brecciated Ellenburger and Upper Elk Point (Devonian, W. Canada) reservoirs, major discrepancies exist between what the paleokarst model predicts and what is actually observed. Reddish calcretes, cavernous porosity and cave cements are absent. Enhanced petrography reveals relict sutured grains, implying burial dolomitization. These same dolomites are brecciated and breccia clasts contain stylolites rotated at different angles to each other and the horizon, implying burial brecciation. Fractures cutting these burial dolomites and stylolites are burial in origin. Preserved secondary porosity is unrelated to brecciated zones and facies controlled. Therefore, brecciation and reservoir quality in both sequences were created by burial dissolution of replacement dolomites and not by subaerial karstification. Brecciation alone does not prove the unconformity-related paleokarst model or the timing of porosity development.

  12. Keys to evaluating [open quotes]paleokarst[close quotes] reservoirs - guidelines from Quaternary carbonates and enhanced petrography

    SciTech Connect

    Dravis, J.J. )

    1996-01-01

    Paleokarst is often invoked to explain reservoir development in ancient brecciated carbonates. However, the paleokarst model is valid only when fabrics seen in Quaternary cave systems are present and petrography of the non-brecciated zones supports subaerial exposure. Quaternary caves typically exhibit early fractures, microscopic to cavernous secondary porosity, solution collapse and brecciation, cave cements, and reddish-brown cave fill. Inter-cavern rocks show fabric-selective dissolution, porosity inversion, precompaction cements, and capping laminated soil crusts. In brecciated Ellenburger and Upper Elk Point (Devonian, W. Canada) reservoirs, major discrepancies exist between what the paleokarst model predicts and what is actually observed. Reddish calcretes, cavernous porosity and cave cements are absent. Enhanced petrography reveals relict sutured grains, implying burial dolomitization. These same dolomites are brecciated and breccia clasts contain stylolites rotated at different angles to each other and the horizon, implying burial brecciation. Fractures cutting these burial dolomites and stylolites are burial in origin. Preserved secondary porosity is unrelated to brecciated zones and facies controlled. Therefore, brecciation and reservoir quality in both sequences were created by burial dissolution of replacement dolomites and not by subaerial karstification. Brecciation alone does not prove the unconformity-related paleokarst model or the timing of porosity development.

  13. 3-D seismic evidence of the effects of carbonate karst collapse on overlying clastic stratigraphy and reservoir compartmentalization

    SciTech Connect

    Hardage, B.A.; Carr, D.L.; Simmons, J.L. Jr.; Jons, R.A.; Lancaster, D.E.; Elphick, R.Y.; Pendleton, V.M.

    1996-09-01

    A multidisciplinary team, composed of stratigraphers, petrophysicists, reservoir engineers, and geophysicists, studied a portion of Boonsville gas field in the Fort Worth Basin of north-central Texas to determine how modern techniques can be combined to understand the mechanisms by which fluvio-deltaic depositional processes create reservoir compartmentalization in a low- to moderate-accommodation basin. An extensive database involving well logs, cores, production, and pressure data from more than 200 wells, 26 mi{sup 2} of 3-D seismic data, vertical seismic profiles, and checkshots was assembled to support this investigation. The authors found the most important geologic influence on stratigraphy and reservoir compartmentalization in this basin to be the existence of numerous karst collapse chimneys over the area covered. These near-vertical karst collapses originated in, or near, the deep Ordovician-age Ellenburger carbonate section and created vertical chimneys extending as high as 2,500 ft above their point of origin, causing significant disruptions in the overlying clastic strata.

  14. Application of sequence stratigraphy to reservoir and hydrocarbon source rock prediction in the Cretaceous carbonate platforms of Maracaibo Basin, Venezuela

    SciTech Connect

    Murat, B.; Azpiritxaga, I. )

    1993-02-01

    Prediction of reservoir and source rocks is enhanced by an understanding of the sequential organization of the sedimentary units. In the Maracaibo Basin, the carbonate Cogollo Group and the basal part of the Shaly La Luna Formation (Upper Barremian to Lower Cenomanian) have been subdivided into a hierarchy of cycles ranging from parasequences (4th and 5th order) up to Regressive-Transgressive cycles (2nd order). Sedimentation during this period on a passive platform under the influence of eustatic sea level fluctuations, led to a succession of about twenty 3rd order sequences (depending on their location on the platform) composed of Transgressive Systems Tracts (TST) and Highstand Systems Tracts (HST). Their boundaries and maximum flooding surfaces can be traced on wireline logs and on cored material. These sequences belong to three Regressive-Transgressive 2nd order cycles showing a 3-stage evolution of infill, aggradation and backstepping. Sedimentary facies vary laterally within systems tracts and vertically from one cycle to another. Most basal TST units display high energy sediments prone to porosity development, whereas the basal HST units are generally characterized by muddier sediments. The best reservoirs are at the top of HST units, with development of both early dolomite and grainy packstones with moderate reservoir quality. Maximum oil productivity occurs where matrix porosity is associated with fractures, which are always best developed within the aggrading stage. Finally, source-rock intervals coincide with the maximum flooding surfaces which limit second order cycles.

  15. Abandoning the mentally ill.

    PubMed

    Barton, R

    1975-12-01

    Mentally ill people have been avoided and abandoned by their families and public authorities for hundreds of years. Present day abandonment includes the deployment of professionals from patients to paper; the destruction of availability and effectiveness of institutional facilities; the obfuscation of mental illness by captious, sematic criticism; the aspirations of paramedical and paraprofessional groups; and the subordination of the primary purpose of institutions and physicians to other objectives. The nature of authority is discussed and the need for the treatment of mentally ill people to be based on the art and science of medicine, rather than the pretension and advocacy of the gullible, unqualified or unscrupulous, is noted.

  16. Geoscience/Engineering Characterization of the Interwell Environment in Carbonate Reservoirs Based on Outcrop Analogs, Permian Basin, West Texas and New Mexico.

    SciTech Connect

    Lucia, Jerry F.; Kerans, Charles

    1997-05-29

    The objective of this project is to investigate styles of reservoir heterogeneity found in low permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study. Subsurface Activities - We continue to prepare two final reports that summarize research results of the South Cowden Field study. One report summarizes results of the petrophysical characterization research, and one summarizes results of the fluid-flow modeling research. Outcrop Activities - We also continue to prepare the final report, which summarizes the research results of the Grayburg outcrop reservoir study.

  17. Geoscience/Engineering Characterization of the Interwell Environment in Carbonate Reservoirs Based on Outcrop Analogs, Permian Basin, West Texas and New Mexico.

    SciTech Connect

    Lucia, Jerry F.; Kerans, Charles

    1997-05-19

    The objective of this project is to investigate styles of reservoir heterogeneity found in low permeability pelleted wackestone/packstone facies and mixed carbonate/clastic facies found in Permian Basin reservoirs by studying similar facies exposed in the Guadalupe Mountains. Specific objectives for the outcrop study include construction of a stratigraphic framework, petrophysical quantification of the framework, and testing the outcrop reservoir model for effects of reservoir heterogeneity on production performance. Specific objectives for the subsurface study parallel objectives for the outcrop study. Subsurface Activities - We continue to prepare two final reports that summarize research results of the South Cowden Field study. One report summarizes results of the petrophysical characterization research, and one summarizes results of the fluid-flow modeling research. Outcrop Activities - We also continue to prepare the final report, which summarizes the research results of the Grayburg outcrop reservoir study.

  18. Improved oil recovery in Mississippian carbonate reservoirs of Kansas: Near term, Class 2. [Annual report], September 18, 1994--October 1, 1995. Draft.

    SciTech Connect

    Carr, T.R.; Green, D.W.; Willhite, G.P.

    1996-01-01

    This report represents a summary of the progress during the first year of Budget period 1 of the near term Class 2 project entitled ``Improved Oil Recovery in Mississippian Carbonate Reservoirs of Kansas``. Two examples of advanced technologies developed as part of this project are highlighted along with the use of the Internet to transfer these technologies. The two advanced technologies are a spread-sheet petrophysical analysis and reservoir evaluation (PfEFFER), and a petrophysical/seismic approach to well logs (pseudoseismic). Work continues on multi-disciplinary reservoir characterization at the demonstration site. The potential for incremental primary recovery is being evaluated using the improved reservoir characterization to target infill drilling and evaluate the potential of a horizontal well. The impact of successful incremental primary recovery from sub-Pennsylvanian unconformity Mississippian reservoirs such as are present at the Schaben demonstration site would be significant for Kansas and the US.

  19. Dry Stream Reaches in Carbonate Terranes: Surface Indicators of Ground-Water Reservoirs

    USGS Publications Warehouse

    Brahana, J.V.; Hollyday, E.F.

    1988-01-01

    In areas where dry stream reaches occur, subsurface drainage successfully competes with surface drainage, and sheet-like dissolution openings have developed parallel to bedding creating the ground-water reservoir. Union Hollow in south-central Tennessee is the setting for a case study that illustrates the application of the dry stream reach technique. In this technique, dry stream reach identification is based on two types of readily acquired information: remotely sensed black and white infrared aerial photography; and surface reconnaissance of stream channel characteristics. Test drilling in Union Hollow subsequent to identification of the dry reach proved that a localized ground-water reservoir was present.

  20. MULTIDISCIPLINARY IMAGING OF ROCK PROPERTIES IN CARBONATE RESERVOIRS FOR FLOW-UNIT TARGETING

    SciTech Connect

    Stephen C. Ruppel

    2003-07-01

    Excellent progress continues to be made on most objectives and goals. Primary focus during the past 6 months has been (1) simulation of reservoir performance using the reservoir model constructed for the Phase 1 study area, (2) extension of core and log characterization activities to the Phase 2 study area, (3) development of an initial velocity-based inversion model from the 3-D seismic volume for porosity characterization, (4) continuation of quality-control analysis of wireline logs. Preliminary results of the study were presented at a technology-transfer workshop in May 2003 in Midland/Odessa Texas.

  1. Facies analysis, diagenesis and sequence stratigraphy of the carbonate-evaporite succession of the Upper Jurassic Surmeh Formation: Impacts on reservoir quality (Salman Oil Field, Persian Gulf, Iran)

    NASA Astrophysics Data System (ADS)

    Beigi, Maryam; Jafarian, Arman; Javanbakht, Mohammad; Wanas, H. A.; Mattern, Frank; Tabatabaei, Amin

    2017-05-01

    This study aims to determine the depositional facies, diagenetic processes and sequence stratigraphic elements of the subsurface carbonate-evaporite succession of the Upper Jurassic (Kimmeridgian-Tithonian) Surmeh Formation of the Salman Oil Field (the Persian Gulf, Iran), in an attempt to explore their impacts on reservoir quality. The Surmeh Formation consists mainly of carbonate rocks, intercalated with evaporite layers. Petrographically, the Surmeh Formation consists of nine microfacies (MF1-MF9). These microfacies are grouped into three facies associations related to three depositional environments (peritidal flat, lagoon and high-energy shoal) sited on the inner part of a homoclinal carbonate ramp. The recorded diagenetic processes include dolomitization, anhydritization, compaction, micritization, neomorphism, dissolution and cementation. Vertical stacking patterns of the studied facies reveal the presence of three third-order depositional sequences, each of which consists of transgressive systems tract (TST) and highstand systems tract (HST). The TSTs comprise intertidal and lagoon facies whereas the HSTs include supratidal and shoal facies. In terms of their impacts on reservoir quality, the shoal facies represent the best reservoir quality, whereas the peritidal and lagoonal facies exhibit moderate to lowest reservoir quality. Also, poikilotopic anhydrite cement played the most significant role in declining the reservoir quality, whereas the widespread dissolution of labile grains and formation of moldic and vuggy pores contributed in enhancing the reservoir quality. In addition, the HSTs have a better reservoir quality than the TSTs. This study represents an approach to use the depositional facies, diagenetic alterations and sequence stratigraphic framework of carbonate -evaporite succession for a more successful reservoir characterization.

  2. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. 1994 Annual report

    SciTech Connect

    Wehner, S.C.

    1995-05-01

    It is anticipated that this project will show that the application of the CO{sub 2} Huff-n-Puff process in shallow shelf carbonates can be economically implemented to recover appreciable volumes of light oil. The goals of the project are the development of guidelines for cost-effective selection of candidate reservoirs and wells, along with estimating recovery potential. The selected site for the demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico. Work is nearing completion on the reservoir characterization components of the project. The near-term emphasis is to, (1) provide an accurate distribution of original oil-in-place on a waterflood pattern entity level, (2) evaluate past recovery efficiencies, (3) perform parametric simulations, and (4) forecast performance for a site specific field demonstration of the proposed technology. Macro zonation now exists throughout the study area and cross-sections are available. The Oil-Water Contact has been defined. Laboratory capillary pressure data was used to define the initial water saturations within the pay horizon. The reservoir`s porosity distribution has been enhanced with the assistance of geostatistical software. Three-Dimensional kriging created the spatial distributions of porosity at interwell locations. Artificial intelligence software was utilized to relate core permeability to core porosity, which in turn was applied to the 3-D geostatistical porosity gridding. An Equation-of-State has been developed and refined for upcoming compositional simulation exercises. Options for local grid-refinement in the model are under consideration. These tasks will be completed by mid-1995, prior to initiating the field demonstrations in the second budget period.

  3. Impact of a large tropical reservoir on riverine transport of sediment, carbon, and nutrients to downstream wetlands

    NASA Astrophysics Data System (ADS)

    Kunz, Manuel J.; Wüest, Alfred; Wehrli, Bernhard; Landert, Jan; Senn, David B.

    2011-12-01

    Large dams can have major ecological and biogeochemical impacts on downstream ecosystems such as wetlands and riparian habitats. We examined sediment removal and carbon (C), nitrogen (N), and phosphorus (P) cycling in Itezhi-Tezhi Reservoir (ITT; area = 364 km2, hydraulic residence time = 0.7 yr), which is located directly upstream of a high ecological value floodplain ecosystem (Kafue Flats) in the Zambezi River Basin. Field investigations (sediment cores, sediment traps, water column samples), mass balance estimates, and a numerical biogeochemical reservoir model were combined to estimate N, P, C, and sediment removal, organic C mineralization, primary production, and N fixation. Since dam completion in 1978, 330 × 103 tons (t) of sediment and 16 × 103, 1.5 × 103, 200 t of C, N, and P, respectively, have accumulated annually in ITT sediments. Approximately 50% of N inputs and 60% of P inputs are removed by the reservoir, illustrating its potential in decreasing nutrients to the downstream Kafue Flats floodplain. The biogeochemical model predicted substantial primary production in ITT (˜280 g C m-2 yr-1), and significant N-fixation (˜30% for the total primary production) was required to support primary production due to marginal inputs of inorganic N. Model simulations indicate that future hydropower development in the reservoir, involving the installation of turbines driven by hypolimnetic water, will likely result in the delivery of low-oxygen waters to downstream ecosystems and increased outputs of dissolved inorganic N and P by a factor of ˜4 and ˜2 compared to current dam management, respectively.

  4. Carboniferous and older carbonate rocks: Lithofacies, extent, and reservoir quality: Chapter CC in The oil and gas resource potential of the Arctic National Wildlife Refuge 1002 area, Alaska

    USGS Publications Warehouse

    Dumoulin, Julie A.

    1999-01-01

    Carboniferous and older carbonate rocks are potential hydrocarbon reservoir facies for four plays in the 1002 area of the Arctic National Wildlife Refuge. These rocks include several units in the pre-Carboniferous basement and the Carboniferous Lisburne Group. Data from exploratory wells west of the 1002 area, outcrops south of the 1002 area, seismic lines, and well logs are synthesized herein to infer carbonate lithofacies, extent, and reservoir character beneath the northeastern Arctic coastal plain.A chiefly shallow-water basement carbonate succession of Late Proterozoic through Early Devonian age (Katakturuk Dolomite, Nanook Limestone, and Mount Copleston Limestone) is interpreted to be present beneath much of the south-central 1002 area; it reaches 3,700 m thick in outcrop and is the primary reservoir for the Deformed Franklinian Play. A more heterogeneous lithologic assemblage of uncertain age forms basement in the northwestern part of the 1002 area; well data define three subunits that contain carbonate intervals 5- 50 m thick. These strata are prospective reservoirs for the Undeformed Franklinian Play and could also be reservoirs for the Niguanak- Aurora Play. Regional lithologic correlations suggest a Cambrian-Late Proterozoic(?) age for subunits one and two, and a slightly younger, later Cambrian-Silurian age for subunit three. Seismic and well data indicate that subunit one overlies subunit two and is overlain by subunit three. The Mississippian and Pennsylvanian Lisburne Group, a predominantly carbonate platform succession as much as 1 km thick, is projected beneath the southernmost part of the 1002 area and is a potential reservoir for the Ellesmerian Thrust-belt and Niguanak-Aurora Plays.Carbonate rocks in the 1002 area probably retain little primary porosity but may have locally well developed secondary porosity. Measured reservoir parameters in basement carbonate strata are low (porosity generally ≤ 5%; permeability ≤ 0.2 md) but drill

  5. Carbon Dioxide Emissions from the Littoral Zone of a Chinese Reservoir, and a Comparison with Other Greenhouse Gases

    NASA Astrophysics Data System (ADS)

    Yang, Meng

    2017-04-01

    The continuous increase in the number of reservoirs in countries like China, India and Brazil has raised important questions about the environmental impact of their greenhouse gases emissions. In particular, the littoral zone may be a hotspot for production of greenhouse gases. We investigated the spatiotemporal variation of CO2 flux at the littoral zone of a Chinese reservoir along a wet-to-dry transect from permanent flooded land, seasonal flooded land to non-flooded dry land, using the static dark chamber technique. The mean total respiration was 346 mg m-2 h-1 (52% of which was contributed by shoots) and the rate varied significantly among water levels, months and time of day. We developed a statistical model which shows that temperature and biomass explain 76% of the variation. Flooding could play a positive role in carbon balance if water recession occurs at the time when carbon gains associated with plant growth overcomes the carbon loss of ecosystem. The overall carbon balance was analysed using cumulative greenhouse gases fluxes and biomass, bringing the data of the present study alongside our published data of CH4 and N2O flux which had been investigated simultaneously. CO2 and CH4 emissions correlated significantly under flooding, while N2O did not show significant correlations with CO2 or CH4 irrespective of whether the land was flooded or not. For the growing season, 11.6 g C m-2 was absorbed by the littoral zone. Taking CH4 and N2O into the calculation showed that permanently flooded sites were a source of greenhouse gases, rather than a sink. We emphasise the importance of taking into account all three gases when evaluating the greenhouse gas budgets of wetland ecosystems.

  6. Impact of stylolitization on diagenesis of a Lower Cretaceous carbonate reservoir from a giant oilfield, Abu Dhabi, United Arab Emirates

    NASA Astrophysics Data System (ADS)

    Paganoni, Matteo; Al Harthi, Amena; Morad, Daniel; Morad, Sadoon; Ceriani, Andrea; Mansurbeg, Howri; Al Suwaidi, Aisha; Al-Aasm, Ihsan S.; Ehrenberg, Stephen N.; Sirat, Manhal

    2016-04-01

    Bed-parallel stylolites are a widespread diagenetic feature in Lower Cretaceous limestone reservoirs, Abu Dhabi, United Arab Emirates (UAE). Diagenetic calcite, dolomite, kaolin and small amounts of pyrite, fluorite, anhydrite and sphalerite occur along and in the vicinity of the stylolites. Petrographic observations, negative δ18OVPDB, fluid inclusion microthermometry, and enrichment in 87Sr suggest that these cements have precipitated from hot basinal brines, which migrated along the stylolites and genetically related microfractures (tension gashes). Fluid migration was presumably related to lateral tectonic compression events related to the foreland basin formation. The low solubility of Al3 + in formation waters suggests that kaolin precipitation was linked to derivation of organic acids during organic matter maturation, probably in siliciclastic source rocks. The mass released from stylolitization was presumably re-precipitated as macro- and microcrystalline calcite cement in the host limestones. The flanks of the oilfield (water zone) display more frequent presence and higher amplitude of stylolites, lower porosity and permeability, higher homogenization temperatures and more radiogenic composition of carbonates compared to the crest (oil zone). This indicates that oil emplacement retards diagenesis. This study demonstrates that stylolitization plays a crucial role in fluid flow and diagenesis of carbonate reservoirs during basin evolution.

  7. Establishment of an oil and gas database for increased recovery and characterization of oil and gas carbonate reservoir heterogeneity. [Jurassic Smackover Formation

    SciTech Connect

    Mancini, E.A.

    1990-01-01

    The objective of this project is to augment the National Reservoir Database (TORIS database), to increase our understanding of geologic heterogeneities that affect the recoveries of oil and gas from carbonate reservoirs in the State of Alabama, and to identify resources that are producible at moderate cost. This objective will be achieved through detailed geological, geostatistical, and engineering characterization of typical Jurassic Smackover Formation hydrocarbon, and engineering characterization of typical Jurassic Smackover Formation hydrocarbon reservoirs in selected productive fields in the state of Alabama. The results of these studies will be used to develop and test mathematical models for prediction of the effects of reservoir heterogeneities in hydrocarbon production. Work to date has focused on completion of Subtasks 1, 2, and 3 of this project. Work on Subtask 4 began in this quarter, and substantial additional work has been accomplished on Subtask 2. Subtask 1 included the survey and tabulation of available reservoir engineering and geological data. Subtask 2 comprises the geologic and engineering characterization of smackover reservoir lithofacies. Subtask 3 includes the geologic modeling of reservoir heterogeneities. Subtask 4 includes the development of reservoir exploitation methodologies for strategic infill drilling. 1 fig.

  8. The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE): Examining the complex Arctic biological-climatologic-hydrologic system

    NASA Astrophysics Data System (ADS)

    McDonald, K. C.; Podest, E.; Miller, C. E.; Dinardo, S. J.

    2012-12-01

    Fundamental aspects of the complex Arctic biological-climatologic-hydrologic system remain poorly quantified. As a result, significant uncertainties exist in the carbon budget of the Arctic ecosystem. NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) is a currently-operational Earth Venture 1 (EV-1) mission that is examining correlations between atmospheric and surface state variables for the Alaskan terrestrial ecosystems. CARVE is conducted through a series of intensive seasonal aircraft campaigns, ground-based observations, and analysis sustained over a 5-year mission timeframe. CARVE employs a C-23 Sherpa aircraft to fly an innovative airborne remote sensing payload. This payload includes an L-band radiometer/radar system and a nadir-viewing spectrometer to deliver simultaneous measurements of land surface state variables that control gas emissions (i.e., soil moisture and inundation, freeze/thaw state, surface temperature) and total atmospheric columns of carbon dioxide, methane, and carbon monoxide. The aircraft payload also includes a gas analyzer that links greenhouse gas measurements directly to World Meteorological Organization standards and provide vertical profile information. CARVE measurement campaigns are scheduled regularly throughout the growing season each year to capture the seasonal variability in Arctic system carbon fluxes associated with the spring thaw, the summer drawdown, and the fall refreeze. Continuous ground-based measurements provide temporal and regional context as well as calibration for CARVE airborne measurements. CARVE bridges critical gaps in our knowledge and understanding of Arctic ecosystems, linkages between the Arctic hydrologic and terrestrial carbon cycles, and the feedbacks from fires and thawing permafrost. Ultimately, CARVE will provide an integrated set of data that will provide unprecedented experimental insights into Arctic carbon cycling. Portions of this work were carried out at the Jet

  9. Quantifying Sources and Fluxes of Aquatic Carbon in U.S. Streams and Reservoirs Using Spatially Referenced Regression Models

    NASA Astrophysics Data System (ADS)

    Boyer, E. W.; Smith, R. A.; Alexander, R. B.; Schwarz, G. E.

    2004-12-01

    Organic carbon (OC) is a critical water quality characteristic in riverine systems that is an important component of the aquatic carbon cycle and energy balance. Examples of processes controlled by OC interactions are complexation of trace metals; enhancement of the solubility of hydrophobic organic contaminants; formation of trihalomethanes in drinking water; and absorption of visible and UV radiation. Organic carbon also can have indirect effects on water quality by influencing internal processes of aquatic ecosystems (e.g. photosynthesis and autotrophic and heterotrophic activity). The importance of organic matter dynamics on water quality has been recognized, but challenges remain in quantitatively addressing OC processes over broad spatial scales in a hydrological context. In this study, we apply spatially referenced watershed models (SPARROW) to statistically estimate long-term mean-annual rates of dissolved- and total- organic carbon export in streams and reservoirs across the conterminous United States. We make use of a GIS framework for the analysis, describing sources, transport, and transformations of organic matter from spatial databases providing characterizations of climate, land use, primary productivity, topography, soils, and geology. This approach is useful because it illustrates spatial patterns of organic carbon fluxes in streamflow, highlighting hot spots (e.g., organic-rich environments in the southeastern coastal plain). Further, our simulations provide estimates of the relative contributions to streams from allochthonous and autochthonous sources. We quantify surface water fluxes of OC with estimates of uncertainty in relation to the overall US carbon budget; our simulations highlight that aquatic sources and sinks of OC may be a more significant component of regional carbon cycling than was previously thought. Further, we are using our simulations to explore the potential role of climate and other changes in the terrestrial environment on

  10. Capillary pressure - saturation relations for supercritical CO2 and brine: Implications for capillary/residual trapping in carbonate reservoirs during geologic carbon sequestration

    NASA Astrophysics Data System (ADS)

    Wang, S.; Tokunaga, T. K.

    2014-12-01

    In geologic carbon sequestration (GCS), data on capillary pressure (Pc) - saturation (Sw) relations are routinely needed to appraise reservoir processes. Capillarity and its hysteresis have been often experimentally studied in oil-water, gas-water and three phase gas-oil-water systems, but fewer works have been reported on scCO2-water under in-situ reservoir conditions. Here, Pc-Sw relations of supercritical (sc) CO2 displacing brine, and brine rewetting the porous medium to trap scCO2 were studied to understand CO2 transport and trapping behavior in carbonate reservoirs under representative reservoir conditions. High-quality drainage and imbibition (and associated capillary pressure hysteresis) curves were measured under elevated temperature and pressure (45 ºC, 8.5 and 12 MPa) for scCO2-brine as well as at room temperature and pressure (23 ºC, 0.1 MPa) for air-brine in unconsolidated limestone and dolomite sand columns using newly developed semi-automated multistep outflow-inflow porous plate apparatus. Drainage and imbibition curves for scCO2-brine deviated from the universal scaling curves for hydrophilic interactions (with greater deviation under higher pressure) and shifted to lower Pc than predicted based on interfacial tension (IFT) changes. Augmented scaling incorporating differences in IFT and contact angle improved the scaling results but the scaled curves still did not converge onto the universal curves. Equilibrium residual trapping of the nonwetting phase was determined at Pc =0 during imbibition. The capillary-trapped amounts of scCO2 were significantly larger than for air. It is concluded that the deviations from the universal capillary scaling curves are caused by scCO2-induced wettability alteration, given the fact that pore geometry remained constant and IFT is well constrained. In-situ wettability alteration by reactive scCO2 is of critical importance and must be accounted for to achieve reliable predictions of CO2 behavior in GCS reservoirs.

  11. Uncovering the Minor Contribution of Land-Cover Change in Upland Forests to the Net Carbon Footprint of a Boreal Hydroelectric Reservoir.

    PubMed

    Dessureault, Pierre-Luc; Boucher, Jean-François; Tremblay, Pascal; Bouchard, Sylvie; Villeneuve, Claude

    2015-07-01

    Hydropower in boreal conditions is generally considered the energy source emitting the least greenhouse gas per kilowatt-hour during its life cycle. The purpose of this study was to assess the relative contribution of the land-use change on the modification of the carbon sinks and sources following the flooding of upland forested territories to create the Eastmain-1 hydroelectric reservoir in Quebec's boreal forest using Carbon Budget Model of the Canadian Forest Sector. Results suggest a carbon sink loss after 100 yr of 300,000 ± 100,000 Mg CO equivalents (COe). A wildfire sensitivity analysis revealed that the ecosystem would have acted as a carbon sink as long as <75% of the territory had burned over the 100-yr-long period. Our long-term net carbon flux estimate resulted in emissions of 4 ± 2 g COe kWh as a contribution to the carbon footprint calculation, one-eighth what was obtained in a recent study that used less precise and less sensitive estimates. Consequently, this study significantly reduces the reported net carbon footprint of this reservoir and reveals how negligible the relative contribution of the land-use change in upland forests to the total net carbon footprint of a hydroelectric reservoir in the boreal zone can be.

  12. Heavy oil reservoirs recoverable by thermal technology. Annual report

    SciTech Connect

    Kujawa, P.

    1981-02-01

    The purpose of this study was to compile data on reservoirs that contain heavy oil in the 8 to 25/sup 0/ API gravity range, contain at least ten million barrels of oil currently in place, and are non-carbonate in lithology. The reservoirs within these constraints were then analyzed in light of applicable recovery technology, either steam-drive or in situ combustion, and then ranked hierarchically as candidate reservoirs. The study is presented in three volumes. Volume I presents the project background and approach, the screening analysis, ranking criteria, and listing of candidate reservoirs. The economic and environmental aspects of heavy oil recovery are included in appendices to this volume. This study provides an extensive basis for heavy oil development, but should be extended to include carbonate reservoirs and tar sands. It is imperative to look at heavy oil reservoirs and projects on an individual basis; it was discovered that operators, and industrial and government analysts will lump heavy oil reservoirs as poor producers, however, it was found that upon detailed analysis, a large number, so categorized, were producing very well. A study also should be conducted on abandoned reservoirs. To utilize heavy oil, refiners will have to add various unit operations to their processes, such as hydrotreaters and hydrodesulfurizers and will require, in most cases, a lighter blending stock. A big problem in producing heavy oil is that of regulation; specifically, it was found that the regulatory constraints are so fluid and changing that one cannot settle on a favorable recovery and production plan with enough confidence in the regulatory requirements to commit capital to the project.

  13. Water-quality assessment of Francis E Walter reservoir, Luzerne and Carbon counties, Pennsylvania

    USGS Publications Warehouse

    Barker, J.L.

    1983-01-01

    Water-quality data, both past and present, show that the waters of the upper Lehigh River basin are somewhat acidic, but otherwise are generally of good quality. This report contains a summary of all known water-quality data collected by the U.S. Geological Survey and other agencies, as well as a synopsis of current water-quality conditions in the reservoir and its tributaries. Water-quality data collected from June 1981 to May 1982 indicate that raising the pool level from 1,300 to approximately 1,392 feet above sea level (NGVD of 1929) has had some significant, if only temporary, detrimental impacts on the reservoir system and its discharge. Depth profile measurements show that, while the impoindment was thermally stratified for only about 2 weeks, the dissolved oxygen concentrations were depressed to levels critical to fishlife throughout much of the reservoir. Another effect of the raised pool was the lowering of pH in the impoinded water. Median pH values were less than 6.0 throughout the reservoir, whereas they commonly exceeded 6.5 at the normal pool elevation. Tests for fecal coliform and fecal streptococcus indicate the impoinded water is nearly free of enteric bacteria. Algal analyses and nutrient concentrations support the premise that the impoundment is nutrient poor and phosphorus limited. Raising the water level an additional 125 feet should have no permanent detrimental effect upon water quality and will greatly increase available habitat for fish and waterflow. Increased retention time should not alter the current trophic status and may decrease the concentration of available nutrients.

  14. Laboratory measurements of large-scale carbon sequestration flows in saline reservoirs

    SciTech Connect

    Backhaus, Scott N

    2010-01-01

    Brine saturated with CO{sub 2} is slightly denser than the original brine causing it to sink to the bottom of a saline reservoir where the CO{sub 2} is safely sequestered. However, the buoyancy of pure CO{sub 2} relative to brine drives it to the top of the reservoir where it collects underneath the cap rock as a separate phase of supercritical fluid. Without additional processes to mix the brine and CO{sub 2}, diffusion in this geometry is slow and would require an unacceptably long time to consume the pure CO{sub 2}. However, gravity and diffusion-driven convective instabilities have been hypothesized that generate enhanced CO{sub 2}-brine mixing promoting dissolution of CO{sub 2} into the brine on time scale of a hundred years. These flows involve a class of hydrodynamic problems that are notoriously difficult to simulate; the simultaneous flow of mUltiple fluids (CO{sub 2} and brine) in porous media (rock or sediment). The hope for direct experimental confirmation of simulations is dim due to the difficulty of obtaining high resolution data from the subsurface and the high pressures ({approx}100 bar), long length scales ({approx}100 meters), and long time scales ({approx}100 years) that are characteristic of these flows. We have performed imaging and mass transfer measurements in similitude-scaled laboratory experiments that provide benchmarks to test reservoir simulation codes and enhance their predictive power.

  15. Response surfaces for CO2 leakage from geologic storage along abandoned wellbores

    NASA Astrophysics Data System (ADS)

    Jordan, A.; Carey, J. W.; Pawar, R. J.; Stauffer, P. H.

    2011-12-01

    The storage of carbon dioxide (CO2) in geologic reservoirs that have previously been drilled for oil and gas exploration is under investigation worldwide as an option for reducing the amount of anthropogenic carbon introduced to the atmosphere. Reservoirs that have already been tapped for hydrocarbon production have several benefits over development of new sites: they tend to be geologically well-understood, with existing wellbore data to help further characterize the local geologic framework; are known to be conducive to trapping buoyant or pressurized fluids; may have infrastructure in place; and are likely to be already impacted ecologically as compared to pristine sites. One downside to using depleted hydrocarbon reservoirs is the potential for CO2 leakage along pre-existing wellbores that were either not designed for CO2 sequestration or have been improperly plugged and abandoned. The primary goal of this study is to develop estimates of possible wellbore leakage rates of CO2 from storage reservoirs to the surface and/or into overlaying aquifers, as a function of wellbore properties and the surrounding geologic framework. The Finite Element Heat and Mass transfer code (FEHM) was used to perform Monte Carlo simulations of multiphase flow along wellbores across a wide range of geologic and wellbore parameters. Several wellbore scenarios were studied, including a simple wellbore between the CO2 storage reservoir and the surface; a wellbore intersecting a saline aquifer ("thief zone"); and a wellbore intersecting both a thief zone and a freshwater aquifer. The Problem Solving environment for Uncertainty Analysis and Design Exploration (PSUADE) software was used to analyze results and produce response surfaces for the estimation of wellbore flow rate as a function of the primary factors that influence leakage. These results will be used to develop abstractions for leakage rates to be incorporated in performance assessments of geologic CO2 storage, which will help

  16. 18 CFR 157.216 - Abandonment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... facilities to be abandoned. (5) For any abandonment resulting in earth disturbance, a USGS 71/2-minute-series... abandoned; (3) The accounting treatment of the facilities abandoned; and (4) The date earth disturbance, if any, related to the abandonment began and the date the facilities were abandoned; and (5) The date of...

  17. 18 CFR 157.216 - Abandonment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... facilities to be abandoned. (5) For any abandonment resulting in earth disturbance, a USGS 71/2-minute-series... abandoned; (3) The accounting treatment of the facilities abandoned; and (4) The date earth disturbance, if any, related to the abandonment began and the date the facilities were abandoned; and (5) The date of...

  18. 18 CFR 157.216 - Abandonment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... facilities to be abandoned. (5) For any abandonment resulting in earth disturbance, a USGS 71/2-minute-series... abandoned; (3) The accounting treatment of the facilities abandoned; and (4) The date earth disturbance, if any, related to the abandonment began and the date the facilities were abandoned; and (5) The date of...

  19. 18 CFR 157.216 - Abandonment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... facilities to be abandoned. (5) For any abandonment resulting in earth disturbance, a USGS 71/2-minute-series... abandoned; (3) The accounting treatment of the facilities abandoned; and (4) The date earth disturbance, if any, related to the abandonment began and the date the facilities were abandoned; and (5) The date of...

  20. 18 CFR 157.216 - Abandonment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... facilities to be abandoned. (5) For any abandonment resulting in earth disturbance, a USGS 71/2-minute-series... abandoned; (3) The accounting treatment of the facilities abandoned; and (4) The date earth disturbance, if any, related to the abandonment began and the date the facilities were abandoned; and (5) The date of...

  1. Dolomite reservoirs: Porosity evolution and reservoir characteristics

    SciTech Connect

    Sun, S.Q.

    1995-02-01

    Systematic analyses of the published record of dolomite reservoirs worldwide reveal that the majority of hydrocarbon-producing dolomite reservoirs occurs in (1) peritidal-dominated carbonate, (2) subtidal carbonate associated with evaporitic tidal flat/lagoon, (3) subtidal carbonate associated with basinal evaporite, and (4) nonevaporitic carbonate sequence associated with topographic high/unconformity, platform-margin buildup or fault/fracture. Reservoir characteristics vary greatly from one dolomite type to another depending upon the original sediment fabric, the mechanism by which dolomite was formed, and the extent to which early formed dolomite was modified by post-dolomitization diagenetic processes (e.g., karstification, fracturing, and burial corrosion). This paper discusses the origin of dolomite porosity and demonstrates the porosity evolution and reservoir characteristics of different dolomite types.

  2. Sediment accumulation and carbon, nitrogen, and phosphorus deposition in the large tropical reservoir Lake Kariba (Zambia/Zimbabwe)

    NASA Astrophysics Data System (ADS)

    Kunz, Manuel J.; Anselmetti, Flavio S.; Wüest, Alfred; Wehrli, Bernhard; Vollenweider, Adrian; Thüring, Silvan; Senn, David B.

    2011-09-01

    Large dams affect the aquatic continuum from land to ocean by accumulating particles and nutrients in their reservoirs. We examined sediment cores to quantify sediment, organic carbon (OC), nitrogen (N), and phosphorous (P) accumulation, and to examine historic changes and spatial variability in the sedimentation pattern in Lake Kariba, the largest hydropower reservoir in the Zambezi River Basin (ZRB). Sediment characteristics (concentrations of OC, N, P; δ13C and δ15N; wet bulk density) showed large variability both with sediment depth and between cores. While organic matter (OM) in river deltas was primarily allochthonous in origin, OM characteristics (δ13C, C:N) in lacustrine sediments suggest that autochthonous sources account for >45% of the OM that accumulates over large areas of the lake. At the same time, the relative contribution of allochthonous material within individual layers of lacustrine cores varied considerably with depth due to discrete flood deposits. The overall sediment accumulation rate in Lake Kariba is on the order of 4 × 106 t yr-1, and the estimated OC accumulation of 120 × 103 t C yr-1 accounts for ˜1‰ of globally buried OC in reservoirs. In addition, mass balance calculations revealed that approximately 70% and 90% of incoming total N and P, respectively, are eliminated from the water column by sedimentation (N, P) and denitrification (N). Since Lake Kariba attenuates flow from ˜50% of the ZRB, these OC, N, and P removals represent a drastic reduction in nutrient loadings to downstream riparian ecosystems and to the coastal Indian Ocean.

  3. Elevated carbon dioxide flux at the Dixie Valley geothermal field, Nevada; relations between surface phenomena and the geothermal reservoir

    USGS Publications Warehouse

    Bergfeld, D.; Goff, F.; Janik, C.J.

    2001-01-01

    In the later part of the 1990s, a large die-off of desert shrubs occurred over an approximately 1 km2 area in the northwestern section of the Dixie Valley (DV) geothermal field. This paper reports results from accumulation-chamber measurements of soil CO2 flux from locations in the dead zone and stable isotope and chemical data on fluids from fumaroles, shallow wells, and geothermal production wells within and adjacent to the dead zone. A cumulative probability plot shows three types of flux sites within the dead zone: Locations with a normal background CO2 flux (7 g m-2 day-1); moderate flux sites displaying "excess" geothermal flux; and high flux sites near young vents and fumaroles. A maximum CO2 flux of 570 g m-2 day-1 was measured at a location adjacent to a fumarole. Using statistical methods appropriate for lognormally distributed populations of data, estimates of the geothermal flux range from 7.5 t day-1 from a 0.14-km2 site near the Stillwater Fault to 0.1 t day-1 from a 0.01 -km2 location of steaming ground on the valley floor. Anomalous CO2 flux is positively correlated with shallow temperature anomalies. The anomalous flux associated with the entire dead zone area declined about 35% over a 6-month period. The decline was most notable at a hot zone located on an alluvial fan and in the SG located on the valley floor. Gas geochemistry indicates that older established fumaroles along the Stillwater Fault and a 2-year-old vent in the lower section of the dead zone discharge a mixture of geothermal gases and air or gases from air-saturated meteoric water (ASMW). Stable isotope data indicate that steam from the smaller fumaroles is produced by ??? 100??C boiling of these mixed fluids and reservoir fluid. Steam from the Senator fumarole (SF) and from shallow wells penetrating the dead zone are probably derived by 140??C to 160??C boiling of reservoir fluid. Carbon-13 isotope data suggest that the reservoir CO2 is produced mainly by thermal decarbonation of

  4. Carbonate reservoirs deposited during sea level lowstands, Permian basin: Occurrence, geometry, facies, and origin of porosity of in-situ buildups

    SciTech Connect

    Mazzullo, S.J. ); Reid, A.M.; Reid, S.T.

    1990-02-01

    Carbonate reservoirs composed of in-situ reefs and associated facies, mostly deposited basinward of shallow platforms during sea level lowstands, are common in Pennsylvanian rocks in the Permian basin. Specific examples include some Atokan and Strawn fields in the Delaware basin, and Canyon-Cisco fields in the Midland basin. Such reservoirs are conspicuous by their absence in Permian rocks, where lowstand facies are instead siliciclastics and detrital carbonates. In-situ lowstand carbonate reservoirs are represented by phylloid algal reefs (Atokan, Canyon-Cisco), crinoid banks locally with some Chaetetes and phylloid algal reefs (Strawn), and bryozoan-algal boundstone reefs (Canyon-Cisco). These facies are associated with bioclastic and, locally, oolitic sandstones. Lowstand reservoirs are both underlain and overlain by deep-water facies, and field geometries range from equidimensional to slightly elongate, generally parallel to platform margins. Porosity in many fields is due to extensive leaching and karsting accompanying subaerial or shallow subsurface meteoric exposure. Accordingly, porosity predictions are best based on knowledge of reconstructed sea level curves. However, many reservoir pore systems have resulted from deep-burial dissolution accompanying chemical compaction and the migration of fluids out of the basin. Porosity predictions in such cases must rely on knowledge of diagenesis and aspects of basin hydrodynamics.

  5. LOSCAR: Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir Model

    NASA Astrophysics Data System (ADS)

    Zeebe, R. E.

    2011-06-01

    The LOSCAR model is designed to efficiently compute the partitioning of carbon between ocean, atmosphere, and sediments on time scales ranging from centuries to millions of years. While a variety of computationally inexpensive carbon cycle models are already available, many are missing a critical sediment component, which is indispensable for long-term integrations. One of LOSCAR's strengths is the coupling of ocean-atmosphere routines to a computationally efficient sediment module. This allows, for instance, adequate computation of CaCO3 dissolution, calcite compensation, and long-term carbon cycle fluxes, including weathering of carbonate and silicate rocks. The ocean component includes various biogeochemical tracers such as total carbon, alkalinity, phosphate, oxygen, and stable carbon isotopes. We have previously published applications of the model tackling future projections of ocean chemistry and weathering, pCO2 sensitivity to carbon cycle perturbations throughout the Cenozoic, and carbon/calcium cycling during the Paleocene-Eocene Thermal Maximum. The focus of the present contribution is the detailed description of the model including numerical architecture, processes and parameterizations, tuning, and examples of input and output. Typical CPU integration times of LOSCAR are of order seconds for several thousand model years on current standard desktop machines. The LOSCAR source code in C can be obtained from the author by sending a request to loscar.model@gmail.com.

  6. INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO

    SciTech Connect

    Ernest A. Mancini

    2003-09-25

    The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling that utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 3 of the project has been reservoir characterization, 3-D modeling, testing of the geologic-engineering model, and technology transfer. This effort has included six tasks: (1) the study of seismic attributes, (2) petrophysical characterization, (3) data integration, (4) the building of the geologic-engineering model, (5) the testing of the geologic-engineering model and (6) technology transfer. This work was scheduled for completion in Year 3. Progress on the project is as follows: geoscientific reservoir characterization is completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions has been completed. Observations regarding the diagenetic

  7. Strontium isotope quantification of siderite, brine and acid mine drainage contributions to abandoned gas well discharges in the Appalachian Plateau

    SciTech Connect

    Chapman, Elizabeth C.; Capo, Rosemary C.; Stewart, Brian W.; Hedin, Robert S.; Weaver, Theodore J.; Edenborn, Harry M.

    2013-04-01

    Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotope mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs.

  8. Extraction of strong beadlike reflections for a carbonate-karst reservoir using a tensor-based adaptive mathematical morphology

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Lu, Wenkai; Wang, Benfeng; Chen, Jianjun; Ding, Jicai

    2017-10-01

    Anomalously high-amplitude bright spots appear on seismic migration sections of carbonate-karst oil-bearing or gas-bearing reservoirs, also called the the string of beads response or strong beadlike reflections (SBRs). Although SBRs have distinct characteristics, it is not easy to detect and extract them from seismic migration sections because the seismic events and noise cannot be completely separated using conventional methods. An algorithm based on adaptive mathematical morphology is proposed in this paper to detect and extract the SBRs for the subsequent quantitative description of karst cave reservoirs. In our proposed method, the instantaneous amplitude section is first obtained with the Hilbert transform. Then, a tensor-based adaptive morphology is introduced to construct the adaptive structure elements which vary from linear to circular shapes according to the local structure tensor. To eliminate the effects of seismic events and noise, the orientations of our designed structural elements are rotated to be the same as the local dominant gradient directions of the instantaneous amplitude section. Finally, a top-hat transform, as a morphological operator, is used to extract the SBRs and remove the effects of seismic events and noise. We demonstrate the validity and effectiveness of our proposed method with field data examples.

  9. Oxygen uptake during mineralization of photosynthesized carbon from phytoplankton of the Barra Bonita reservoir: a mesocosm study.

    PubMed

    Cunha-Santino, M B; Gouvêa, S P; Bianchini, I; Vieira, A A H

    2008-02-01

    This study aimed to discuss and describe the oxygen consumption during aerobic mineralization of organic products (cells and excretion products) from five unialgal cultures: Cryptomonas sp., Microcystis aeruginosa, Anabaena spiroides, Thalassiosira sp. and Aulacoseira granulata. These species were isolated from Barra Bonita reservoir (22 degrees 29' S and 48 degrees 34' W) and cultivated in the laboratory. From each culture, two decomposition chambers were prepared; each chamber contained about 130 mg.L(-1) of carbon from water samples of the reservoir. The chambers were aerated and incubated in the dark at 20.0 degrees C. The concentration of dissolved oxygen, pH values and electrical conductivity of the solutions were determined during a period of 10 days. The results indicated increases in oxygen consumption for all the solutions studied and also for electrical conductivity. The pH values presented a decreasing tendency throughout the experiment. Oxygen consumption varied from 43 (Aulacoseira granulata chamber) to 345 mg O2 g(-1) C (Anabaena spiroides chamber). Decrease in pH values was probably due to increase in CO2 concentration from microbial respiration. Increase in electrical conductivity might be due to the liberation of ions during decomposition. The results demonstrate the potentiality of the studied genera in influencing oxygen availability followed by a die-off event. It also indicates the possibility of changing of the electrical conductivity and pH values in the water column due the aerobic algae mineralization.

  10. Prediction of compressional wave velocity by an artificial neural network using some conventional well logs in a carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Zoveidavianpoor, Mansoor; Samsuri, Ariffin; Shadizadeh, Seyed Reza

    2013-08-01

    As vital records for the upstream petroleum industry, compressional-wave (Vp) data provide important information for reservoir exploration and development activities. Due to the different nature and behaviour of the influencing parameters, more complex nonlinearity exists for Vp modelling purposes. Therefore, formulating a prediction tool that can accurately estimate the lacking log data, such as Vp, is of prime importance. Therefore, an attempt has been made to develop a prediction model for Vp as a function of some conventional well logs by using an artificial neural network (ANN). The obtained results are compared to those of multiple linear regression (MLR) models. A total of 2156 data points from a giant Middle Eastern carbonate reservoir, derived from a conventional wire line and a dipole sonic imager log were used in this study. The efficiency of the employed approach, quantified in terms of the mean squared error correlation coefficient (R-square), and prediction efficiency error, is evaluated through simulation and the results are presented. The result showed that an ANN outperforms MLRs and was found to be more robust and reliable.

  11. Fracture system influence on the reservoirs rock formation of Ordovician-Devonian carbonates in West Siberia tectonic depression

    NASA Astrophysics Data System (ADS)

    Koveshnikov, A. E.; Nesterova, A. C.; Dolgaya, T. F.

    2016-09-01

    During the Paleozoic period from the beginning of the Cambrian to the end of the Carboniferous in the boundaries of the West Siberia tectonic depression there occurred the sea, where the carbonate platforms were formed by the limestones accumulation. All the area at the end of the Carboniferous period was turned to land. Resulting from Gertsynskaya folding in the times of Permian - Triassic the formed deposits were folded and denudated to a considerable extent. Besides, the reservoir rocks of the crust of weathering including redeposited one, were formed as a result of hypergenesis, during the continental stand of the area in the near-surface zone. A new geological prospecting unit has been suggested which underlies these crusts of weathering and formed during fracture tectonic processes with hydrothermal-metasomatic limestones reworking and the processes of hydrothermal leaching and dolomitization. So, in the carbonate platforms the system of fissure zones related to tectonic disturbance was formed. This has a dendrite profile where the series of tangential, more thinned fractures deviate from the stem and finish in pores and caverns. The carbonate platforms formation in the West Siberia tectonic depression has been analyzed, their dynamics and gradual increasing from the minimal in Ordovician and Silurian to maximal at the end of the Late Devonian has been shown.

  12. An Evaluation of the Carbon Sequestration Potential of the Cambro-Ordovician Strata of the Illinois and Michigan Basins. Part 1. Evaluation of Phase 2 CO2 Injection Testing in the Deep Saline Gunter Sandstone Reservoir (Cambro-Ordovician Knox Group), Marvin Blan No. 1 Hancock County, Kentucky Part 2. Time-lapse Three-Dimensional Vertical Seismic Profile (3D-VSP) of Sequestration Target Interval with Injected Fluids

    SciTech Connect

    Bowersox, Richard; Hickman, John; Leetaru, Hannes

    2012-12-20

    Part 1 of this report focuses on results of the western Kentucky carbon storage test, and provides a basis for evaluating injection and storage of supercritical CO2 in Cambro-Ordovician carbonate reservoirs throughout the U.S. Midcontinent. This test demonstrated that the Cambro- Ordovician Knox Group, including the Beekmantown Dolomite, Gunter Sandstone, and Copper Ridge Dolomite in stratigraphic succession from shallowest to deepest, had reservoir properties suitable for supercritical CO2 storage in a deep saline reservoir hosted in carbonate rocks, and that strata with properties sufficient for long-term confinement of supercritical CO2 were present in the deep subsurface. Injection testing with brine and CO2 was completed in two phases. The first phase, a joint project by the Kentucky Geological Survey and the Western Kentucky Carbon Storage Foundation, drilled the Marvin Blan No. 1 carbon storage research well and tested the entire Knox Group section in the open borehole – including the Beekmantown Dolomite, Gunter Sandstone, and Copper Ridge Dolomite – at 1152–2255 m, below casing cemented at 1116 m. During Phase 1 injection testing, most of the 297 tonnes of supercritical CO2 was displaced into porous and permeable sections of the lowermost Beekmantown below 1463 m and Gunter. The wellbore was then temporarily abandoned with a retrievable bridge plug in casing at 1105 m and two downhole pressure-temperature monitoring gauges below the bridge plug pending subsequent testing. Pressure and temperature data were recorded every minute for slightly more than a year, providing a unique record of subsurface reservoir conditions in the Knox. In contrast, Phase 2 testing, this study, tested a mechanically-isolated dolomitic-sandstone interval in the Gunter.

  13. 4D seismic to image a thin carbonate reservoir during a miscible C02 flood: Hall-Gurney Field, Kansas, USA

    USGS Publications Warehouse

    Raef, A.E.; Miller, R.D.; Franseen, E.K.; Byrnes, A.P.; Watney, W.L.; Harrison, W.E.

    2005-01-01

    The movement of miscible CO2 injected into a shallow (900 m) thin (3.6-6m) carbonate reservoir was monitored using the high-resolution parallel progressive blanking (PPB) approach. The approach concentrated on repeatability during acquisition and processing, and use of amplitude envelope 4D horizon attributes. Comparison of production data and reservoir simulations to seismic images provided a measure of the effectiveness of time-lapse (TL) to detect weak anomalies associated with changes in fluid concentration. Specifically, the method aided in the analysis of high-resolution data to distinguish subtle seismic characteristics and associated trends related to depositional lithofacies and geometries and structural elements of this carbonate reservoir that impact fluid character and EOR efforts.

  14. Characterization of carbonate reservoir property changes due to dissolution for far-field conditions of CO2 storage

    NASA Astrophysics Data System (ADS)

    Mangane, P. O.; Gouze, P.; Luquot, L.

    2012-12-01

    Geological storage of CO2 in reservoir pore fluid (e.g. deep saline aquifers), is one of the diverse technologies being explored for deacreasing atmospheric CO2 concentration. After injecting the CO2 as a supercritical fluid at depth, it will slowly dissolve into the pore water producing low pH fluids with a high capacity for dissolving carbonates and consequently changing irreversibly the hydrodynamical properties of the reservoir. Characterizing these changes is essential for modelling flow and CO2 transport during and after the CO2 injection. Here we report experimental results from the injection of the CO2-saturated brine into two distinct limestone cores (a bioclastic carbonate and an oolitic carbonate) of 9 mm diameter, 18 mm length. 3D high-resolution X-ray microtomography (XRMT) of the rock sample have been performed before and after the experiments. The experiments were performed using in-situ sequestration conditions (P = 12MPa and T = 100°C), and notably, under chemical conditions given at the position far away from the well injection site (i.e area where the volume of dissolved CO2 into the brine is low, due to CO2 consumption by the dissolution processes occured during its transport from the well injection site). Permeability k is calculated from the pressure drop across the sample and porosity Φ is deduced from chemical concentration of the outlet fluid. The change of the pore structure is analysed in terms of connectivity, tortuosity and fluid-rock interface from processing the XRMT images. These experiments show that far from the well injection site, dissolution processes are characterized by slow mass tranfer including, in the case of carbonate rock, transport of fine particles, which locally clog the porous space. Then, that leads to the damage of the carbonate reservoir both in terms of connectivity of the porous space and CO2 hydrodynamical storage capacity. In fact, the results of the two experiments show that the porosity decreased locally

  15. The self-similar solutions of the problem of carbon dioxide injection into the reservoir saturated with methane and its hydrate

    NASA Astrophysics Data System (ADS)

    Musakaev, N. G.; Khasanov, M. K.

    2016-10-01

    In this paper the research of carbon dioxide injection into a porous medium initially saturated with methane and its hydrate was performed. The mathematical model of heat and mass transfer in a porous media, accompanied by the formation of carbon dioxide hydrate, is presented. The self-similar solutions, for the axisymmetric problem definition, were built. These solutions describe the distribution of the fluid parameters in a reservoir.

  16. Design and Implementation of a CO2 Flood Utilizing Advanced Reservoir Characterization and Horizontal Injection Wells In a Shallow Shelf Carbonate Approaching Waterflood Depletion

    SciTech Connect

    Czirr, Kirk

    1999-10-28

    The first project objective is to utilize reservoir characterization and advanced technologies to optimize the design of a carbon dioxide (CO2) project for the South Cowden Unit (SCU) located in Ector County, Texas. The SCU is a mature, relatively small, shallow shelf carbonate unit nearing waterflood depletion. The second project objective is to demonstrate the performance and economic viability of the project in the field. All work during the second quarter falls within the demonstration project.

  17. Seismic amplitude variation with offset: Its effects on weighted stacking, and its uses in characterization of sandstone and carbonate reservoirs

    NASA Astrophysics Data System (ADS)

    Madiba, Gislain Bolouvi

    An algorithm for weighted stacking, which is not particularly expensive in terms of computer time or memory and can be easily incorporated into routine processing is proposed. A comprehensive comparison of the proposed weighted stacking algorithm and the conventional stacking algorithm is conducted through testing on synthetics and a real data set from New Mexico, USA. This weighted stacking algorithm achieves the primary goal of signal-to-noise ratio improvement while at the same time providing better resolution, wider bandwidth, and a higher signal-to-noise ratio than the conventional stack. A novel hydrocarbon indicator [the water-filled porosity (S wv)], which is estimated from the ratio of P-velocity to S-velocity (Vp/Vs), is proposed and applied to characterize clastic hydrocarbon reservoirs in the North Sea. The separation between pore fluids and lithologies is enhanced by mapping from V p/Vs to Swv using an empirical crossplot-derived relationship. The Swv-V p/Vs plane still does not produce unique interpretations in many situations. However, the critical distinction, which is between hydrocarbon-bearing sands and all other geologic/reservoir configurations, is defined. Porosity is the dominant factor controlling reservoir signature for carbonate rocks. Acoustic impedance and seismic amplitudes are porosity and lithology indicators. Angle-dependent reflectivity effects are introduced for determination of fluid charactersitics by simultaneous elastic impedance inversion of three non-overlapping migrated common-angle stacked sections for P- and S-impedance (Ip and Is). Deviations of points from a water-filled baseline in the Ip-I s plane define a gas potential section that is used for direct identification of gas zones in the dolomitized limestone reservoirs of the Turner Valley Formation in southern Alberta, Canada. There is consistency with the known gas production at a well and agreement with gas index sections obtained through the use of Lame parameter

  18. Imaging Faults in Carbonate Reservoir using Full Waveform Inversion and Reverse Time Migration of Walkaway VSP Data

    NASA Astrophysics Data System (ADS)

    Takam Takougang, E. M.; Bouzidi, Y.

    2016-12-01

    Multi-offset Vertical Seismic Profile (walkaway VSP) data were collected in an oil field located in a shallow water environment dominated by carbonate rocks, offshore the United Arab Emirates. The purpose of the survey was to provide structural information of the reservoir, around and away from the borehole. Five parallel lines were collected using an air gun at 25 m shot interval and 4 m source depth. A typical recording tool with 20 receivers spaced every 15.1 m, and located in a deviated borehole with an angle varying between 0 and 24 degree from the vertical direction, was used to record the data. The recording tool was deployed at different depths for each line, from 521 m to 2742 m depth. Smaller offsets were used for shallow receivers and larger offsets for deeper receivers. The lines merged to form the input dataset for waveform tomography. The total length of the combined lines was 9 km, containing 1344 shots and 100 receivers in the borehole located half-way down. Acoustic full waveform inversion was applied in the frequency domain to derive a high resolution velocity model. The final velocity model derived after the inversion using the frequencies 5-40 Hz, showed good correlation with velocities estimated from vertical incidence VSP and sonic log, confirming the success of the inversion. The velocity model showed anomalous low values in areas that correlate with known location of hydrocarbon reservoir. Pre-stack depth Reverse time migration was then applied using the final velocity model from waveform inversion and the up-going wavefield from the input data. The final estimated source signature from waveform inversion was used as input source for reverse time migration. To save computational memory and time, every 3 shots were used during reverse time migration and the data were low-pass filtered to 30 Hz. Migration artifacts were attenuated using a second order derivative filter. The final migration image shows a good correlation with the waveform

  19. Amplitude-versus-angle analysis and wide-angle-inversion of crosswell seismic data in a carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Ibrahim, Mohamed S.

    pronounced for thinner reservoirs, particularly those beyond the vertical resolution of the seismic. For any interface imaged from above and from beneath, the results AVA characters must result from identical contrasts in elastic properties in the two sets of images, albeit in reverse order. An inversion approach to handle both datasets simultaneously, at pre-critical angles, is demonstrated in this work. The main exploration problem for carbonate reefs is determining the porosity distribution. Images of elastic properties, obtained from deterministic and geostatistical simultaneous inversion of a high-resolution crosswell seismic survey were used to obtain the internal structure and reservoir properties (porosity) of Niagaran Michigan reef. The images obtained are the best of any Niagaran pinnacle reef to date.

  20. INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO

    SciTech Connect

    Ernest A. Mancini

    2004-02-25

    The University of Alabama, in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company, has undertaken an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling which utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary goal of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. Geoscientific reservoir property, geophysical seismic attribute, petrophysical property, and engineering property characterization has shown that reef (thrombolite) and shoal reservoir lithofacies developed on the flanks of high-relief crystalline basement paleohighs (Vocation Field example) and on the crest and flanks of low-relief crystalline basement paleohighs (Appleton Field example). The reef thrombolite lithofacies have higher reservoir quality than the shoal lithofacies due to overall higher permeabilities and greater interconnectivity. Thrombolite dolostone flow units, which are dominated by dolomite intercrystalline and vuggy pores, are characterized by a pore system comprised of a higher percentage of large-sized pores and larger pore throats. Rock-fluid interactions (diagenesis) studies have shown that although the primary control on

  1. Key Factors for Determining Risk of Groundwater Impacts Due to Leakage from Geologic Carbon Sequestration Reservoirs

    SciTech Connect

    Carroll, Susan; Keating, Elizabeth; Mansoor, Kayyum; Dai, Zhenue; Sun, Yunwei; Trainor-Guitton, Whitney; Brown, Chris; Bacon, Diana

    2014-01-06

    The National Risk Assessment Partnership (NRAP) is developing a science-based toolset for the analysis of potential impacts to groundwater chemistry from CO2 injection (www.netldoe.gov/nrap). The toolset adopts a stochastic approach in which predictions address uncertainties in shallow underwater and leakage scenarios. It is derived from detailed physics and chemistry simulation results that are used to train more computationally efficient models,l referred to here as reduced-order models (ROMs), for each component system. In particular, these tools can be used to help regulators and operators understand the expected sizes and longevity of plumes in pH, TDS, and dissolved metals that could result from a leakage of brine and/or CO2 from a storage reservoir into aquifers. This information can inform, for example, decisions on monitoring strategies that are both effective and efficient. We have used this approach to develop predictive reduced-order models for two common types of reservoirs, but the approach could be used to develop a model for a specific aquifer or other common types of aquifers. In this paper we describe potential impacts to groundwater quality due to CO2 and brine leakage, discuss an approach to calculate thresholds under which "no impact" to groundwater occurs, describe the time scale for impact on groundwater, and discuss the probability of detecting a groundwater plume should leakage occur.

  2. Reduced sulfur-carbon-water systems on Mars may yield shallow methane hydrate reservoirs

    NASA Astrophysics Data System (ADS)

    Elwood Madden, M. E.; Leeman, J. R.; Root, M. J.; Gainey, S.

    2011-02-01

    Methane clathrate hydrate reservoirs capped by overlying permafrost have been proposed as potential sources of atmospheric methane plumes on Mars. However, the surface flux of methane from hydrate dissociation is limited by the diffusion rate of methane through the overlying ice. Assuming hydrates underlay the entire plume footprint, the maximum diffusion path length is expected to be less than 15 m, depths too shallow to stabilize pure methane hydrates under Mars geothermal and lithostatic conditions at low to mid latitudes. Therefore, pure methane hydrates confined within permafrost could not produce methane surface fluxes of the magnitude observed near the equator. However, the addition of 10% H 2S, a secondary gas commonly associated with methane production on Earth, expands the hydrate stability field, with clathrates expected within 10 m of the surface at the equator and at depths less than 1 m at higher latitudes. This indicates that H 2S would also be expected to be released as well as methane if the plumes have a confined hydrate reservoir source.

  3. Organic matter turnover in reservoirs of the Harz Mountains (Germany): evidence from 13C/12C changes in dissolved inorganic carbon

    NASA Astrophysics Data System (ADS)

    Barth, Johannes A. C.; Nenning, Franziska; van Geldern, Robert; Mader, Michael; Friese, Kurt

    2014-05-01

    The Harz Mountains in Germany host several reservoirs for drinking water and electricity supply, the largest of which is the Rappbode System with its two pre-reservoirs. They are the Hassel and the Rappbode pre-reservoirs that have about the same size. These pre-reservoirs were investigated in a comparative study in order to quantify turnover of dissolved organic carbon (DOC) as a representative for organic matter. The objective was to find out how organic matter turnover in these reservoirs may affect dissolved inorganic carbon (DIC) and related CO2 dynamics. Depth profiles of dissolved organic and inorganic carbon (DOC and DIC) were established together with their carbon stable isotope distributions (expressed as δ13CDIC and δ13CDOC). Our results showed up to 104 % increase of DIC contents by organic matter turnover when calculated via isotope mass balances. This contrasted observations of DIC concentration differences between waters collected at the surface and at 12 m depth. These concentration comparisons showed much less DIC increases, and in some cases even decreases, between surface and bottom waters. Such discrepancies could be explained by formation of CO2 at depths below the photic zone that reached calculated values above 7000 ppmV. Such high CO2 concentrations may have reduced the DIC pool by upwards migration. Despite such a concentration decrease, turnover of organic matter has likely incorporated its isotope signal into the DIC pool. While not all DOC present was transposed to DIC, other forms of organic matter from sediments may also have transferred their isotope ratio on the DIC pool. However, with its stable isotope ratio of -28.5 permille the measured DOC was representative of C3 plants and can be assumed as a proxy for other forms of sedimentary carbon including carbon from pore waters and particulate organic matter. Other carbon turnover, including DOC leaching, increased import to the reservoirs after precipitation events and

  4. Miscibility study of carbon dioxide injection to enhance oil recovery from Abu-Dhabi oil field Thani reservoire

    NASA Astrophysics Data System (ADS)

    Aljarwan, Abdulla Humaid Saif Saeed

    The subject field in this study has been recognized among the largest offshore oil fields in the world, located in the Arabian Gulf 63 kilometers to the Northwest of Abu Dhabi, producing large quantities of crude oil and associated gas from three different carbonate reservoirs, Thani-I, II and IIII since 1963. In the early 1970's peripheral water injection scheme was adopted to maintain the reservoir pressure and sustain production. Simultaneously, partial waterflooding was applied to one sector of the field, but stopped soon after implementation shadowed by poor sweep efficiency and dramatic escalation of water-cut. Furthermore, hydrocarbon miscible gas injection was implemented in the year 2000 but stopped seven years later, due to high gas oil ratio and aspheltene deposition. In light of such recovery complications, management is considering serious recovery measures to extend plateau production and meet long-term production from this field. Post initial screening phase, it became evident that CO 2 miscible injection is the most suitable way forward. Characteristics of the Thani-III reservoir are within the favorable range for both immiscible and miscible CO2 injection criteria set by Taber, Martine and Serigh. Thani-III reservoir is considered more homogenous, less fractured and with higher production potential than Thani-I and II, hence promoted to be the target of CO2 miscible gas injection. This thesis aims to study the miscibility features of CO2 miscible injecton to enhanced oil recovery from Thani-III reservoir. Comprehensive simulation model is used to determine multi contact miscibility and suitable equation of state with CO2 as a separate pseudo component using one of the industry standard simulation software. Experimental PVT data for bottom hole and separator samples including compositional analysis, differential liberation test, separator tests, constant composition expansion, viscosity measurements and swelling tests for pure CO2 were used to

  5. Effect of Reservoir Anisotropy on Carbon Dioxide Dissolution-Induced Density-Driven Convection

    NASA Astrophysics Data System (ADS)

    Kneafsey, T. J.; Pruess, K.

    2011-12-01

    Sequestering carbon dioxide by injecting it into non-potable aquifers overlain by suitable cap rock is being widely considered and field tested to reduce greenhouse gas emissions to the atmosphere. Being less dense than local brine, supercritical carbon dioxide introduced into the aquifer will tend to spread beneath the cap rock. Numerical and experimental investigations have shown that beneath the buoyant carbon dioxide layer, carbon dioxide dissolution into the brine will increase the density of the brine, resulting in an unstable condition in which denser brine overlies less dense brine. This instability can lead to dissolution-induced density-driven convection of the carbon dioxide laden brine, enhancing dissolution and the permanence of the sequestration. We have performed a series of visualization and quantitative laboratory experiments with homogeneous, heterogeneous, and anisotropic media to examine this process. Our visualization experiments have shown dense finger formation and flow into the underlying brine. These experiments have led us to quantitative measurements of density-driven convection from carbon dioxide dissolution under a variety of conditions. These conditions include high and low permeability porous media, layered media, and fluids including pure water and various brines. Density-driven convection was quantified by measuring the carbon dioxide uptake rate for the systems, and comparing it to the predicted diffusive uptake rate. Uptake rates exceeding the diffusive uptake rate are indicative of convection. Our results show the effects of density-driven convection were smaller for lower permeability and higher salinity conditions, whereas strong convection occurred for pure water in a highly permeable medium. Quantitative tests investigating the effect of anisotropy were based on visualization test results and layered systems were used in the experiments. Detailed experimental results and interpretation of these tests will also be discussed.

  6. Capillary pressure-saturation relations for supercritical CO2 and brine in limestone/dolomite sands: implications for geologic carbon sequestration in carbonate reservoirs.

    PubMed

    Wang, Shibo; Tokunaga, Tetsu K

    2015-06-16

    In geologic carbon sequestration, capillary pressure (Pc)-saturation (Sw) relations are needed to predict reservoir processes. Capillarity and its hysteresis have been extensively studied in oil-water and gas-water systems, but few measurements have been reported for supercritical (sc) CO2-water. Here, Pc-Sw relations of scCO2 displacing brine (drainage), and brine rewetting (imbibition) were studied to understand CO2 transport and trapping behavior under reservoir conditions. Hysteretic drainage and imbibition Pc-Sw curves were measured in limestone sands at 45 °C under elevated pressures (8.5 and 12.0 MPa) for scCO2-brine, and in limestone and dolomite sands at 23 °C (0.1 MPa) for air-brine using a new computer programmed porous plate apparatus. scCO2-brine drainage and imbibition curves shifted to lower Pc relative to predictions based on interfacial tension, and therefore deviated from capillary scaling predictions for hydrophilic interactions. Fitting universal scaled drainage and imbibition curves show that wettability alteration resulted from scCO2 exposure over the course of months-long experiments. Residual trapping of the nonwetting phases was determined at Pc = 0 during imbibition. Amounts of trapped scCO2 were significantly larger than for those for air, and increased with pressure (depth), initial scCO2 saturation, and time. These results have important implications for scCO2 distribution, trapping, and leakage potential.

  7. MULTIDISCIPLINARY IMAGING OF ROCK PROPERTIES IN CARBONATE RESERVOIRS FOR FLOW-UNIT TARGETING

    SciTech Connect

    Stephen C. Ruppel

    2003-01-01

    Excellent progress has been made on all project objectives and goals. All tasks have been completed in the Phase 1 study area, the initial area of project focus. Primary elements of this work include the following: The stratigraphic architecture has been established through correlation of wireline logs guided by core and outcrop studies of facies and cyclicity. A porosity model has been developed that creates a basis for calculation of porosity for wells in the study area. Rock fabrics have been defined by sampling, analysis, and description of cores and used to create transforms for calculating permeability and oil saturation from porosity data. Finally, a preliminary 3-D model has been constructed that incorporates stratigraphic architecture, rock-fabric data, and petrophysical data. Reservoir volumetrics calculated from the model show that a very large fraction of the original oil in place remains.

  8. Simulation study to determine the feasibility of injecting hydrogen sulfide, carbon dioxide and nitrogen gas injection to improve gas and oil recovery oil-rim reservoir

    NASA Astrophysics Data System (ADS)

    Eid, Mohamed El Gohary

    This study is combining two important and complicated processes; Enhanced Oil Recovery, EOR, from the oil rim and Enhanced Gas Recovery, EGR from the gas cap using nonhydrocarbon injection gases. EOR is proven technology that is continuously evolving to meet increased demand and oil production and desire to augment oil reserves. On the other hand, the rapid growth of the industrial and urban development has generated an unprecedented power demand, particularly during summer months. The required gas supplies to meet this demand are being stretched. To free up gas supply, alternative injectants to hydrocarbon gas are being reviewed to support reservoir pressure and maximize oil and gas recovery in oil rim reservoirs. In this study, a multi layered heterogeneous gas reservoir with an oil rim was selected to identify the most optimized development plan for maximum oil and gas recovery. The integrated reservoir characterization model and the pertinent transformed reservoir simulation history matched model were quality assured and quality checked. The development scheme is identified, in which the pattern and completion of the wells are optimized to best adapt to the heterogeneity of the reservoir. Lateral and maximum block contact holes will be investigated. The non-hydrocarbon gases considered for this study are hydrogen sulphide, carbon dioxide and nitrogen, utilized to investigate miscible and immiscible EOR processes. In November 2010, re-vaporization study, was completed successfully, the first in the UAE, with an ultimate objective is to examine the gas and condensate production in gas reservoir using non hydrocarbon gases. Field development options and proces schemes as well as reservoir management and long term business plans including phases of implementation will be identified and assured. The development option that maximizes the ultimate recovery factor will be evaluated and selected. The study achieved satisfactory results in integrating gas and oil

  9. Role of parasequence-scale sequence stratigraphic analysis in integrated reservoir characterization and modeling of shallow-water carbonate strata

    SciTech Connect

    Kerans, C.; Lucia, F.J.; Bebout, D.G.; Major, R.P.; Ruppel, S.C. )

    1991-03-01

    The predictable stacking patterns of parasequences within different systems tracts of a sequence and of facies and rock-fabric successions within parasequences provide a powerful conceptual framework for integrated analysis of carbonate reservoirs. Stratigraphic analysis using a parasequence approach emphasizes correlation through comparative mapping of genetically related facies successions rather than the classic marker bed approach. The basic shallow-water carbonate parasequence is the upward-shallowing cycle ({approximately}fifth-order cycle, average period {minus}20,000 yr) that records a single progradational event represented most often by an upward-coarsening facies/rock-fabric succession. Interpretation of depositional environment is best accomplished at the parasequence scale because lateral facies relationships within these units best approximate time-equivalent genetically related deposits. The upward-shallowing facies succession that forms a parasequence provides a natural framework for quantification of geologic descriptions through rock-fabric-oriented petrophysical analysis. Permeability and saturation are directly related to sediment grain size, sorting, and interparticle porosity. Grain-dominated rocks have higher permeability and oil-saturation values than do mud-dominated rocks with the same interparticle porosity. Grain size and sorting occur systematically and predictably in the upward-shallowing parasequences. Porosity, grain size, and sorting can be significantly altered by diagenetic processes such as dolomitization, cementation, and dissolution. Diagenetic overprints are, however, commonly controlled by the depositional textures and thus also are predictable.

  10. 4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

    SciTech Connect

    Richard D. Miller; Abdelmoneam E. Raef; Alan P. Byrnes; William E. Harrison

    2007-06-30

    The objective of this research project was to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data in the hopes of observing changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE No.DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestones of the Lansing-Kansas City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 30 months of seismic monitoring, one baseline and eight monitor surveys clearly detected changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators and observed in production data. Attribute analysis was a very useful tool in enhancing changes in seismic character present, but difficult to interpret on time amplitude slices. Lessons learned from and tools/techniques developed during this project will allow high-resolution seismic imaging to be routinely applied to many CO{sub 2} injection programs in a large percentage of shallow carbonate oil fields in the midcontinent.

  11. Sedimentological cross section of Cambro-Ordovician carbonate shelf (Knox group, Conassauga Formation) in central Alabama: facies, diagenesis, potential reservoirs

    SciTech Connect

    Sternbach, L.R.

    1984-04-01

    Cambro-Ordovician thrust-imbricated carbonates in central Alabama are the focus of renewed exploration interest. Samples from east-west-trending core holes within the surface-most thrust plates reconstruct the carbonate shelf and shelf-edge facies before deformation. The Upper Cambrian shelf margin now is in the subsurface of Talledega County; coeval dolostones in the western part of the state represent the former shelf interior. Rock analogs to former environments include the following. (1) Barrier shoals (Conasauga Formation) - dark colored, partially dolomitized ooid and skeletal grainstones. (2) Submerged back-barrier and offshelf dolomitized sediments (lower Knox Group) - western belt: finely crystalline algal thrombolites, fenestral dolopelmicrites, rippled beds; eastern belt: finely laminated dolostones, slope-derived pebbles and graded beds. (3) Tidal flats (upper Knox Group) - light-colored, crystalline dolostones, dolomitized pellet grainstones, algal laminites, pseudomorphs after sulfates and early diagenetic chertification. (4) Former emergent shelf -(Knox unconformity)-pelmicrite, skeletal wackestones, erosional chert pebble conglomerate. Multiple possibilities for hydrocarbon reservoirs appear throughout the sequence. Vuggy and intercrystalline dolostone porosity is primarily in the lower Knox formations. Primary interparticle pores are retained in lower Knox algal buildups. Breccia porosity occurs in the strata below the Knox unconformity through solution of the underlying Knox Group. Fractures in the subsurface are believed to enhance permeability in all porosity types.

  12. Sedimentological cross section of Cambro-Ordovician carbonate shelf (Knox group, Conasauga Formation) in central Alabama: facies, diagenesis, potential reservoirs

    SciTech Connect

    Sternbach, L.R.

    1984-04-01

    Cambro-Ordovician thrust-imbricated carbonates in central Alabama are the focus of renewed exploration interest. Samples from east-west-trending core holes within the surface-most thrust plates reconstruct the carbonate shelf and shelf-edge facies before deformation. The Upper Cambrian shelf margin now is in the subsurface of Talledega County; coeval dolostones in the western part of the state represent the former shelf interior. Rock analogs to former environments include the following. (1) Barrier shoals (Conasauga Formation) - dark colored, partially dolomitized ooid and skeletal grainstones. (2) Submerged back-barrier and offshelf dolomitized sediments (lower Knox Group) - western belt: finely crystalline algal thrombolites, fenestral dolopelmicrites, rippled beds; eastern belt: finely laminated dolostones, slope-derived pebbles and graded beds. (3) Tidal flats (upper Knox Group) - light-colored, crystalline dolostones, dolomitized pellet grainstones, algal laminites, pseudomorphs after sulfates and early diagenetic chertification. (4) Former emergent shelf -(Knox unconformity)-pelmicrite, skeletal wackestones, erosional chert pebble conglomerate. Multiple possibilities for hydrocarbon reservoirs appear throughout the sequence. Vuggy and intercrystalline dolostone porosity is primarily in the lower Knox formations. Primary interparticle pores are retained in lower Knox algal buildups. Breccia porosity occurs in the strata below the Knox unconformity through solution of the underlying Knox Group. Fractures in the subsurface are believed to enhance permeability in all porosity types.

  13. Integrated Outcrop and Subsurface Studies of the Interwell Environment of Carbonate Reservoirs: Clear Fork (Leonaradian Age) Reservoirs, West Texas and New Mexico

    SciTech Connect

    Lucia, F. Jerry; Jennings, Jr., James W.

    2001-05-08

    A preliminary reservoir model was constructed for the Lower Clear Fork of the South Wasson Clear Fork reservoir. The model was constructed by calibrating high-frequency cycles observed in cores to the porosity log. The rock fabrics mostly fall in petrophysical class 1, and cross plots of porosity and water saturation could not be used to identify rock fabrics. Data from two limestone fields and one dolostone field were presented to support the contention that grain-dominated fabrics have higher porosity than mud-dominated fabrics do and that this difference is retained when the limestone is dolomitized.

  14. In-filled reservoirs serving as sediment archives to analyse soil organic carbon erosion - A case study from the Karoo rangelands

    NASA Astrophysics Data System (ADS)

    Krenz, Juliane; Greenwood, Philip; Heckrath, Goswin; Kuhn, Brigitte; Kuhn, Nikolaus

    2017-04-01

    Covering about 41 % of the Earth's Land Surface drylands provide a range of ecosystem services for more than one third of the world population. Threatened by climate change and incorrect land use their natural land cover is changing and land degradation is one of their major problems. The semi-arid rangelands of the Great Karoo region in South Africa are just one example of a region that has experienced a number of environmental changes. After European farmers settled in the late 18th century agricultural activities increased, leading to overgrazing and probably representing a trigger to land degradation. As a consequence of a higher water demand and shifting rainfall patterns many dams and small reservoirs have been constructed to provide drinking water for cattle or to facilitate irrigation during dry periods. High erosion rates lead to a fast filling-up of reservoirs and thereby reduced their storage capacities. Thus, most of the dams are nowadays dry (filled with sediment) or even breached. In this ongoing project, a combination of analytical methods that include drone imagery, landscape mapping, erosion modelling and sediment analysis have been employed to determine whether land degradation in the Karoo has resulted in the reversion from a net sink of C to a net source of C. Sediment deposits from three silted-up reservoirs were analysed for varying physicochemical parameters, in order to analyse and reconstruct erosional and depositional patterns. A sharp decrease in total carbon content with decreasing depth for two reservoirs suggests that land degradation during and after the post-European settlement most likely triggered erosion of the relatively fertile surface soils, which presumably in-filled the reservoirs. It is assumed that the carbon-rich bottom layers of the dam deposits originate from these eroded surface soils. Low organic Carbon (OC) content in the top layers of the reservoir in-fill, and in the eroded source areas, supports the assumption that

  15. Geothermal prospection in the Greater Geneva Basin (Switzerland and France). Impact of diagenesis on reservoir properties of the Upper Jurassic carbonate sediments

    NASA Astrophysics Data System (ADS)

    Makhloufi, Yasin; Rusillon, Elme; Brentini, Maud; Clerc, Nicolas; Meyer, Michel; Samankassou, Elias

    2017-04-01

    Diagenesis of carbonate rocks is known to affect the petrophysical properties (porosity, permeability) of the host rock. Assessing the diagenetic history of the rock is thus essential when evaluating any reservoir exploitation project. The Canton of Geneva (Switzerland) is currently exploring the opportunities for geothermal energy exploitation in the Great Geneva Basin (GGB) sub-surface. In this context, a structural analysis of the basin (Clerc et al., 2016) associated with reservoir appraisal (Brentini et al., 2017) and rock-typing of reservoir bodies of potential interest were conducted (Rusillon et al., 2017). Other geothermal exploitation projects elsewhere (e.g. Bavaria, south Germany, Paris Basin, France) showed that dolomitized carbonate rocks have good reservoir properties and are suitable for geothermal energy production. The objectives of this work are to (1) describe and characterize the dolomitized bodies in the GGB and especially their diagenetic history and (2) quantify the reservoir properties of those bodies (porosity, permeability). Currently, our study focuses on the Upper Jurassic sedimentary bodies of the GGB. Field and well data show that the dolomitization is not ubiquitous in the GGB. Results from the petrographical analyses of the Kimmeridgian cores (Humilly-2) and of field analogues (Jura, Saleve and Vuache mountains) display complex diagenetic histories, dependent of the study sites. The paragenesis exhibits several stages of interparticular calcite cementation as well as different stages of dolomitization and/or dedolomitization. Those processes seem to follow constrained path of fluid migrations through burial, faulting or exhumation during the basin's history. These complex diagenetic histories affected the petrophysical and microstructural properties via porogenesis (conservation of initial porosity, moldic porosity) and/or poronecrosis events. The best reservoir properties appear to be recorded in patch reef and peri

  16. From fractures to flow: A field-based quantitative analysis of an outcropping carbonate reservoir

    NASA Astrophysics Data System (ADS)

    Agosta, F.; Alessandroni, M.; Antonellini, M.; Tondi, E.; Giorgioni, M.

    2010-07-01

    Fractures can play an important role in the fluid storage-migration properties of fault damage zones. In this present contribution, we document the role exerted by fractures on fluid flow in carbonate damage zones of hydrocarbon-bearing, km-long, oblique-slip normal faults with 10's of m-throw. The carbonate fault damage zones were analysed by mean of scan line surveys conducted in both tar-free and tar-rich outcrops. In this way, the relationships among the individual fracture characteristics (length, spacing, aperture, orientation, connectivity and distance from slip surfaces pertaining to small faults of the fault damage zones) and hydrocarbons have been established. Data obtained by scan line surveys were also used to compute the amount of fracture porosity, the degree of fracture connectivity and, based upon simple assumptions, the orientation of the local σhmax at times of faulting. Additionally, scan line surveys were also carried out along outcrops exposing unfaulted carbonate host rocks. The results of our computation are consistent with a carbonate host rock made up of a quite isotropic fracture array comprised of isolated and coupled fractures, in which individual fracture sets have negative exponential spacing distributions. In terms of fluid flow, the fracture array of the carbonate host rock enhances the fluid storage. Conversely, the fracture array of the fault damage zones is characterized by a pronounced anisotropy due to interconnected fractures, which enhance the fluid migration. Fractures in the fault damage zones include those inherited from background deformation and others related to the faulting processes. The latter fracture sets are characterized by power law spacing distributions. In conclusion, counter-intuitively, both fracture length and fracture spacing do not have any correlation with hydrocarbons in the fault damage zones. On the contrary, fracture anisotropy, fracture spread and fracture orientation are positively correlated with

  17. ADVANCED CHARACTERIZATION OF FRACTURED RESERVOIRS IN CARBONATE ROCKS: THE MICHIGAN BASIN

    SciTech Connect

    James R. Wood; William B. Harrison

    2002-12-01

    The purpose of the study was to collect and analyze existing data on the Michigan Basin for fracture patterns on scales ranging form thin section to basin. The data acquisition phase has been successfully concluded with the compilation of several large digital databases containing nearly all the existing information on formation tops, lithology and hydrocarbon production over the entire Michigan Basin. These databases represent the cumulative result of over 80 years of drilling and exploration. Plotting and examination of these data show that contrary to most depictions, the Michigan Basin is in fact extensively faulted and fractured, particularly in the central portion of the basin. This is in contrast to most of the existing work on the Michigan Basin, which tends to show relatively simple structure with few or minor faults. It also appears that these fractures and faults control the Paleozoic sediment deposition, the subsequent hydrocarbon traps and very likely the regional dolomitization patterns. Recent work has revealed that a detailed fracture pattern exists in the interior of the Central Michigan Basin, which is related to the mid-continent gravity high. The inference is that early Precambrian, ({approx}1 Ga) rifting events presumed by many to account for the gravity anomaly subsequently controlled Paleozoic sedimentation and later hydrocarbon accumulation. There is a systematic relationship between the faults and a number of gas and oil reservoirs: major hydrocarbon accumulations consistently occur in small anticlines on the upthrown side of the faults. The main tools used in this study to map the fault/fracture patterns are detailed, close-interval (CI = 10 feet) contouring of the formation top picks accompanied by a new way of visualizing the data using a special color spectrum to bring out the third dimension. In addition, recent improvements in visualization and contouring software were instrumental in the study. Dolomitization is common in the

  18. Maximizing Storage Rate and Capacity and Insuring the Environmental Integrity of Carbon Dioxide Sequestration in Geological Reservoirs

    SciTech Connect

    L.A. Davis; A.L. Graham; H.W. Parker; J.R. Abbott; M.S. Ingber; A.A. Mammoli; L.A. Mondy; Quanxin Guo; Ahmed Abou-Sayed

    2005-12-07

    Maximizing Storage Rate and Capacity and Insuring the Environmental Integrity of Carbon Dioxide Sequestration in Geological Formations The U.S. and other countries may enter into an agreement that will require a significant reduction in CO2 emissions in the medium to long term. In order to achieve such goals without drastic reductions in fossil fuel usage, CO2 must be removed from the atmosphere and be stored in acceptable reservoirs. The research outlined in this proposal deals with developing a methodology to determine the suitability of a particular geologic formation for the long-term storage of CO2 and technologies for the economical transfer and storage of CO2 in these formations. A novel well-logging technique using nuclear-magnetic resonance (NMR) will be developed to characterize the geologic formation including the integrity and quality of the reservoir seal (cap rock). Well-logging using NMR does not require coring, and hence, can be performed much more quickly and efficiently. The key element in the economical transfer and storage of the CO2 is hydraulic fracturing the formation to achieve greater lateral spreads and higher throughputs of CO2. Transport, compression, and drilling represent the main costs in CO2 sequestration. The combination of well-logging and hydraulic fracturing has the potential of minimizing these costs. It is possible through hydraulic fracturing to reduce the number of injection wells by an order of magnitude. Many issues will be addressed as part of the proposed research to maximize the storage rate and capacity and insure the environmental integrity of CO2 sequestration in geological formations. First, correlations between formation properties and NMR relaxation times will be firmly established. A detailed experimental program will be conducted to determine these correlations. Second, improved hydraulic fracturing models will be developed which are suitable for CO2 sequestration as opposed to enhanced oil recovery (EOR

  19. A parametric analysis of capillary pressure effects during the carbon sequestration injection process in a sandstone reservoir

    NASA Astrophysics Data System (ADS)

    Wu, H.; Pollyea, R.

    2016-12-01

    Geological Carbon Sequestration (GCS) is considered as a key method for mitigating the adverse effects of steadily increasing atmospheric CO2 concentrations. Numerical simulation is one technique for better understanding the injection, migration and leakage of supercritical CO2 (scCO2) during GCS. At the field scale, capillary pressure (Pcap) is an important factor governing the subsurface movement of scCO2. Constitutive models of Pcap as a function of wetting phase saturation (Sw) are essential to field-scale GCS simulations; however, such Pcap models are based on core-scale laboratory measurements. As a result, there exists uncertainty in the application of laboratory-measured Pcap models to field-scale GCS simulations. In this study, a parametric analysis of commonly used van Genucthen Pcap model is undertaken to quantify the effects of variability in the model parameter space. The study focuses on two parameters: the non-wetting phase entry pressure (P0) and the pore-size distribution index (λ), the latter of which controls curvature of the Pcap model. A two-dimensional parameter space is selected that covers a wide range of laboratory-scale Pcap measurements in the scCO2-brine system, and scCO2 injection processes are modeled within a homogeneous sandstone reservoir over the complete parameter space. Simulation results demonstrate how changes in the Pcap model parameters influence scCO2 migration within the storage reservoir. Maximum injection pressure is largely insensitive to variability of Pcap model parameters; however, vertical scCO2 migration is strongly controlled by Pcap model parameter selection. Since vertical scCO2 migration is the key point to estimate scCO2 leakage risk through caprock sealing, these results illustrate the importance of Pcap model parameter selection in field-scale numerical models of GCS.

  20. The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) FTS: Results From the 2012/13 Alaska Campaigns

    NASA Astrophysics Data System (ADS)

    Kurosu, Thomas P.; Miller, Charles E.; Dinardo, Stephen J.

    2014-05-01

    The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) is an aircraft-based Earth Venture 1 mission to study the carbon balance of the Alaskan Arctic ecosystem, with a particular focus on carbon release from melting permafrost. Operating from its base in Fairbanks, AK, the CARVE aircraft covers a range of principle flight paths in the Alaskan interior, the Yukon River valley, and the northern Alaska coast around Barrow and Dead Horse. Flight paths are chosen to maximize ecosystem variability and cover burn-recovery/regrowth sequences. CARVE observations cover the Arctic Spring/Summer/Fall seasons, with multiple flights per season and principle flight path. Science operations started in May 2012 and are currently envisaged to continue until 2015. The CARVE suite of instruments includes flask measurements, in situ gas analyzers for CO2, CH4 and CO observations, and a three-band polarizing Fourier Transform Spectrometer (FTS) for column measurements of CO2, CH4, CO, their interfering species (e.g., H2O), and O2. The FTS covers the spectral regions of 4,200-4,900 cm-1, 5,800-6,400 cm-1, and 12,900-13,200 cm-1, with a spectral resolution of 0.2 cm-1. Aircraft-based FTS science observations in Alaska have been performed since 23-05-2012. First-version data products from all CARVE instruments derived from observations during the 2012 campaign were publicly released earlier in 2013. The FTS has performed well during flight conditions, particularly with respect to vibration damping. Outstanding challenges include the need for improved spectral and radiometric calibration, as well as compensating for low signal-to-noise spectra acquired under Alaskan flight conditions. We present results from FTS column observations of CO2, CH4, and CO, observed during the 2012 and 2013 campaigns, including preliminary comparisons of CARVE FTS measurements with satellite observations of CO2 from TANSO/GOSAT and CO from MOPITT.

  1. TSR versus non-TSR processes and their impact on gas geochemistry and carbon stable isotopes in Carboniferous, Permian and Lower Triassic marine carbonate gas reservoirs in the Eastern Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Liu, Q. Y.; Worden, R. H.; Jin, Z. J.; Liu, W. H.; Li, J.; Gao, B.; Zhang, D. W.; Hu, A. P.; Yang, C.

    2013-01-01

    The Palaeozoic and lowermost Mesozoic marine carbonate reservoirs of the Sichuan Basin in China contain variably sour and very dry gas. The source of the gas in the Carboniferous, Permian and Lower Triassic reservoirs is not known for certain and it has proved difficult to discriminate and differentiate the effects of thermal cracking- and TSR-related processes for these gases. Sixty-three gas samples were collected and analysed for their composition and carbon stable isotope values. The gases are all typically very dry (alkane gases being >97.5% methane), with low (<1%) nitrogen and highly variable H2S and CO2. Carboniferous gas is negligibly sour while the Lower Triassic gas tends to be most sour. The elevated H2S (up to 62%) is due to thermochemical sulphate reduction with the most sour Triassic and Permian reservoirs being deeper than 4800 m. The non-TSR affected Carboniferous gas is a secondary gas that was derived from the cracking of sapropelic kerogen-derived oil and primary gas and is highly mature. Carboniferous (and non-sour Triassic and Permian) gas has unusual carbon isotopes with methane and propane being isotopically heavier than ethane (a reversal of typical low- to moderate-maturity patterns). The gas in the non-sour Triassic and Permian reservoirs has the same geochemical and isotopic characteristics (and therefore the same source) as the Carboniferous gas. TSR in the deepest Triassic reservoirs altered the gas composition reaching 100% dryness in the deepest, most sour reservoirs showing that ethane and propane react faster than methane during TSR. Ethane evolves to heavier carbon isotope values than methane during TSR leading to removal of the reversed alkane gas isotope trend found in the Carboniferous and non-sour Triassic and Permian reservoirs. However, methane was directly involved in TSR as shown by the progressive increase in its carbon isotope ratio as gas souring proceeded. CO2 increased in concentration as gas souring proceeded, but

  2. Drake passage and central american seaway controls on the distribution of the oceanic carbon reservoir

    SciTech Connect

    Fyke, Jeremy G.; D'Orgeville, Marc; Weaver, Andrew J.

    2015-05-01

    A coupled carbon/climate model is used to explore the impact of Drake Passage opening and Central American Seaway closure on the distribution of carbon in the global oceans. We find that gateway evolution likely played an important role in setting the modern day distribution of oceanic dissolved inorganic carbon (DIC), which is currently characterized by relatively low concentrations in the Atlantic ocean, and high concentrations in the Southern, Indian, and Pacific oceans. In agreement with previous studies, we find a closed Drake Passage in the presence of an open Central American Seaway results in suppressed Atlantic meridional overturning and enhanced southern hemispheric deep convection. Opening of the Drake Passage triggers Antarctic Circumpolar Current flow and a weak Atlantic meridional overturning circulation (AMOC). Subsequent Central American Seaway closure reinforces the AMOC while also stagnating equatorial Pacific subsurface waters. These gateway-derived oceanographic changes are reflected in large shifts to the global distribution of DIC. An initially closed Drake Passage results in high DIC concentrations in the Atlantic and Arctic oceans, and lower DIC concentrations in the Pacific/Indian/Southern oceans. Opening Drake Passage reverses this gradient by lowering mid-depth Atlantic and Arctic DIC concentrations and raising deep Pacific/Indian/Southern Ocean DIC concentrations. Central American Seaway closure further reinforces this trend through additional Atlantic mid-depth DIC decreases, as well as Pacific mid-depth DIC concentration increases, with the net effect being a transition to a modern distribution of oceanic DIC.

  3. Drake passage and central american seaway controls on the distribution of the oceanic carbon reservoir

    DOE PAGES

    Fyke, Jeremy G.; D'Orgeville, Marc; Weaver, Andrew J.

    2015-05-01

    A coupled carbon/climate model is used to explore the impact of Drake Passage opening and Central American Seaway closure on the distribution of carbon in the global oceans. We find that gateway evolution likely played an important role in setting the modern day distribution of oceanic dissolved inorganic carbon (DIC), which is currently characterized by relatively low concentrations in the Atlantic ocean, and high concentrations in the Southern, Indian, and Pacific oceans. In agreement with previous studies, we find a closed Drake Passage in the presence of an open Central American Seaway results in suppressed Atlantic meridional overturning and enhancedmore » southern hemispheric deep convection. Opening of the Drake Passage triggers Antarctic Circumpolar Current flow and a weak Atlantic meridional overturning circulation (AMOC). Subsequent Central American Seaway closure reinforces the AMOC while also stagnating equatorial Pacific subsurface waters. These gateway-derived oceanographic changes are reflected in large shifts to the global distribution of DIC. An initially closed Drake Passage results in high DIC concentrations in the Atlantic and Arctic oceans, and lower DIC concentrations in the Pacific/Indian/Southern oceans. Opening Drake Passage reverses this gradient by lowering mid-depth Atlantic and Arctic DIC concentrations and raising deep Pacific/Indian/Southern Ocean DIC concentrations. Central American Seaway closure further reinforces this trend through additional Atlantic mid-depth DIC decreases, as well as Pacific mid-depth DIC concentration increases, with the net effect being a transition to a modern distribution of oceanic DIC.« less

  4. Ordovician carbonate buildups: Potential gas reservoirs in the Ordos basin, central China

    SciTech Connect

    Huaida Hsu )

    1991-03-01

    The Ordos basin of central China covers an area of about 25,000 km{sup 2}. A series of eastward moving overthrusts developed along its western flank, but most of the basin consists of a stable slope that dips westward less than one degree. The basin contains sediments from Sinian to Middle Ordovician and from the Middle Carboniferous to Cretaceous. Its evolutionary history is similar to that of the Alberta basin. Recently drilled wildcat wells have produced commercial gas flows that are closely associated with Ordovician carbonate buildups and a weathered surface between the Ordovician and Carboniferous. Most of the buildups consist of agal mounds; however, some Middle Ordovician reefs developed in the western portion and along the southern margin of the Ordos basin. More than 200 buildups were delineated using seismic stratigraphic techniques. They can be divided into four distinct types. The growth and distribution of buildups were controlled by sea-level fluctuations. The interpretations made in this study were based on the integration of results from a variety of analyses including vertical profiling, differential interformational velocity analysis, amplitude versus offset comparisons, G-log analysis, seismic modeling techniques, and high-precision gravity surveys. The best gas prospects are the Ordovician carbonate buildups distributed around the basin's central uplift. The delineation of carbonate buildups and the demonstration that they are associated with commercial gas flows open the gate for future gas exploration in this area.

  5. Grassland fire effect on soil organic carbon reservoirs in a semiarid environment

    NASA Astrophysics Data System (ADS)

    Novara, A.; Gristina, L.; Rühl, J.; Pasta, S.; D'Angelo, G.; La Mantia, T.; Pereira, P.

    2013-10-01

    The aim of this work was to investigate the effect of an experimental fire used for grassland management on soil organic carbon (SOC) stocks. The study was carried out on Hyparrhenia hirta (L.) Stapf (Hh) grassland and Ampelodesmos mauritanicus (Desf.) T. Durand & Schinz (Am) grasslands located in the north of Sicily. Soil samples were collected at 0-5 cm before and after the experimental fire, and SOC was measured. During the grassland fire, soil surface temperature was monitored. Biomass of both grasses was analysed in order to determine dry weight and its chemical composition. The results showed that SOC varied significantly with vegetation type, while it is not affected in the short term by grassland fire. Am grassland stored more SOC compared with Hh grassland thanks to lower content in the biomass of the labile carbon pool. No significant difference was observed in SOC before and after fire, which could be caused by several factors: first, in both grassland types the measured soil temperature during fire was low due to thin litter layers; second, in a semiarid environment, a higher mineralization rate results in a lower soil carbon labile pool; and third, the SOC stored in the finest soil fractions, physically protected, is not affected by fire.

  6. The Abandonment of Social Studies?

    ERIC Educational Resources Information Center

    Griffith, Bryant

    1991-01-01

    Addresses the question of whether the social studies should be abandoned. Discusses Kieran Egan's analysis of the importance of storytelling and Egan's proposal to abandon the social studies curriculum in favor of a pedagogy more consistent with the way children think. Critiques Egan's view and examines implications for educators. (SG)

  7. The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE): Five Years of Insights into the High Latitude Carbon Cycle

    NASA Astrophysics Data System (ADS)

    Miller, C. E.

    2015-12-01

    CARVE is a NASA Earth Ventures (EV-1) investigation designed to quantify correlations between atmospheric and surface state variables for the Alaskan terrestrial ecosystems through intensive seasonal aircraft campaigns, ground-based observations, and analysis. In 2015 CARVE completed its 5-year mission. CARVE campaigns across the 2012-2015 growing seasons have established a baseline for monthly, regional scale estimates for surface-atmosphere fluxes of carbon dioxide (CO2) and methane (CH4), and begun to elucidate their environmental and biogeochemical controls. We find that large interannual variability in biogenic CH4 and CO2 fluxes, fire, and significant cold season fluxes complicate attempts to estimate accurate annual C budgets or C balance trends for high latitude ecosystems. We discuss our current estimates for seasonal to interannual CH4 and CO2 fluxes as well as lessons lea