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1

Norwegian Offshore Stratigraphic Lexicon (NORLEX)  

NASA Astrophysics Data System (ADS)

The Norwegian Offshore Stratigraphic Lexicon (NORLEX) provides a relational stratigraphic database for the North Sea, Norwegian Sea, Barents Sea and Svalbard. Both regional lithostratigraphy and biostratigraphy are being substantially updated, following guidelines laid out in the International Stratigraphic Guide. The main body of information developed is available as a petroleum consortium (oracle-style) database, and the new lithostratigraphic definitions as a public domain (paper) document. NORLEX is presented as a browsing website via the internet at http://www.nhm.uio.no/norlex. Seismic cross-sections, core photographs, well logs, field outcrops, microfossil occurrences and other vital attributes are relationally cross-linked. In addition, there are menus for instantly finding updated formation and member tops or microfossil events in all wells, plus a map contouring routine for unit thicknesses and depths. Several new initiatives will expand data and user coverage: 1. Overhaul of Mesozoic stratigraphy, especially Triassic and Cretaceous, in the Barents Sea. 2. Coverage of East Greenland 3. Linkage to UK and Belgium and The Netherlands surface and subsurface stratigraphy 4. Creation of a Sequence Stratigraphic Framework for specific regions. 5. A national microfossil atlas to support zonations 6. Tight linkage to the basin datapacks in TimeScaleCreator Pro, as developed for Australia, New Zealand, Brasil, Gulf of Mexico, Canada and Russia. NORLEX may thus evolve to become STRATLEX, covering many basin regions.

Gradstein, Felix M.; Hammer, Oyvind; Brunstad, Harald; Charnock, Mike; Hellem, Terje; Sigve Lervik, Kjell; Anthonissen, Erik

2010-05-01

2

Sequence stratigraphic framework of Neogene strata in offshore Nigeria  

SciTech Connect

The western portion of the Nigerian continental margin (Dahomey Basin) exhibits stable to moderately unstable progradation. Systems tracts are similar to those described by Vail for stable progradational margins. In contrast, strata off the central and eastern portions of the Nigerian coast (Niger Delta Complex) exhibit highly unstable progradation, and systems tracts are similar to those in Neogene strata of the offshore Gulf of Mexico. Lowstand basin floor fans in both areas are defined by a well-developed upper reflection. This reflection downlaps along the sequence boundary or abuts against the downthrown side of a growth fault surface. Most lower lowstand (slope fan) strata exhibit discontinuous to semi-continuous subparallel reflections. However, this systems tract also contains channel complexes characterized by chaotic bedding with small bright spots and less common large channels, which exhibit concave-upward reflections. In the western portion of the study area, lower lowstand deposits commonly pinch out on the slope. Deposition occurred largely from point sources. In contrast, contemporaneous shallow-water facies are developed in lower lowstand systems tracts in the Niger Delta Complex. Deposition occurred along a line source. Large amplitude anomalies in the upper lowstand (prograding wedge) suggest well-developed sheet sands occur in shallow-water and deep-water in the Niger Delta complex. However, in the Dahomey Basin there is little evidence of deep-water sands in this interval. The transgressive and highstand systems tracts are usually very thin in outer shelf to basin floor strata in both areas. Both the Dahomey Basin and Niger Delta Complex exhibit different stratigraphic geometries, and therefore, require different exploration strategies.

Pacht, J.A. [Seis Strat Services, Inc., Sugar Land, TX (United States); Bowen, B.E.; Hall, D.J. [Excalibur Consulting, Houston, TX (United States)] [and others

1996-08-01

3

Structural and stratigraphic evolution of the East Georges Bank Basin, offshore Nova Scotia, Canada  

SciTech Connect

The East Georges Bank Basin is located offshore Nova Scotia on the southeastern Canadian continental shelf. The basin covers 2.5 million ac and is one of the last undrilled basins in North America. The geological interpretation is almost entirely based on 16,000 km of seismic data over the basin. Pertinent well control is limited to 10 wells on the US portion of the Georges Bank (West Georges Bank Basin) and two wells on the Scotian shelf. Seismic-stratigraphic analysis of this data has led to a structural and stratigraphic model for the basin. The basin formed during the Triassic when the landmass of Pange began separating along rift zones. A prominent Paleozoic basement high, the Yarmouth Arch separated the East Georges Bank Basin from the West Georges Bank Basin and had a dominant influence on sedimentation until the Middle Jurassic. Early synrift sequences consist of lacustrine clastics and shales. Marine incursions began in the late Triassic resulting in massive salt deposits that reflect the restricted extent of the basin and the arid Triassic and Early Jurassic climate. Further continental separation during the Early Jurassic resulted in deposition of carbonates and evaporites followed by Middle Jurassic continental shelf carbonates and deltaic sands. During the Middle Jurassic, major growth faulting and halokinesis was initiated by progradation of the deltaic sands. Post Middle Jurassic continental spreading in combination with changing climatic conditions resulted in a steady decline of carbonate sedimentation and dominance of clastic deposition throughout the remaining history of the basin.

Carswell, A.B. (Esso Canada Resources Ltd., Calgary, Alberta (Canada)); Koning, T. (Texaco Canada Petroleum, Inc., Calgary, Alberta (Canada)); Hibbs, D.C. (Conoco Canada Ltd., Calgary, Alberta (Canada))

1990-05-01

4

Offshore well test platform system  

SciTech Connect

This patent describes an offshore well test platform system positionable above one or more underwater wells. It comprises: a submergible buoy to be restrained below the surface of the water and above one or more underwater wells; a platform structure connectable to the buoy and having an upper portion extending above the surface of the water when connected to the buoy in an installed condition; a well test platform deck connected to the upper portion of the platformed structure; flexible riser means extendable between the one or more underwater wells and the platform deck for providing passage therethrough for well test or workover operations; and restraining means for connecting the submerged buoy to subsea anchors. The restraining means consists of equally spaced, laterally extending tensioned anchoring means having a single intersection of mooring forces at or above the platform deck.

Chiu, H.; Nelsen, D.K.

1990-03-06

5

Seismic stratigraphic record of transpression and uplift on the Romanche transform margin, offshore Ghana  

NASA Astrophysics Data System (ADS)

Recently, available multi-channel seismic reflection data from offshore Ghana have been reprocessed to probe the eastern Romanche Fracture Zone (RFZ) of the Equatorial Atlantic and the sedimentary basins of the paleotransform margin. The RFZ terminates landward in a submarine canyon, up to 2 km deep and >50 km wide, variably filled with submarine fans and projects landward into a Neoproterozoic dextral shear zone. By contrast, the RFZ to the southwest is represented by an ENE submarine escarpment juxtaposing continental and oceanic crusts. Three major sedimentary sequences representing pre-, syn- and post-rift strata have been identified from the seismic profiles and calibrated with chronostratigraphic data from oil exploration wells. The pre-rift sequence consists largely of Paleozoic strata ranging in age from Devonian to Carboniferous. The overlying syn-rift sequence, which was deposited during the intracontinental shearing stage, consists of Aptian to Albian silicilastic strata with distinct continental facies. The seismic sections provide some of the clearest images yet of: (i) folding associated with transform displacement, and (ii) southwest increasing subaerial erosion and stratal discordance. We attribute lateral variation in erosion to crustal thickening associated with folding and to transient thermal effect of ridge-transform interaction which is predicted to produce westward increasing uplift on this margin.

Attoh, Kodjopa; Brown, Larry; Guo, Jingru; Heanlein, Joel

2004-01-01

6

The Role of Sequence Stratigraphic Analysis in the Messinian crisis at Baltim Area, Off-Shore Nile Delta, Egypt  

NASA Astrophysics Data System (ADS)

The Egyptian Nile Delta has recognized over the different human civilizations, as the source of life/ basket of wheat. In the recent time, the Nile Delta revealed another hidden treasure that hidden below the Mediterranean Sea within its sediments. This treasure reflects a number of giant gas reservoirs that require only the suitable technology and the assured ideas to commence injecting gas into the industrial veins of the growing Egyptian economy. The current study is aiming to discuss the Messinian Prospectivity of the concerned area, which is located in the offshore of the Nile Delta, about 25 Km from the Mediterranean Sea shoreline. An integrated exploration approach applied for a selected area, using a variety of subsurface borehole geologic and log data of the selected wells distributed in the study area, as well as biostratigraphic data. The well data comprise well markers, and electric logs (e.g. gamma ray, density, neutron and sonic logs), where the geological data represented by litho-stratigraphic information, as well as ditch samples analysis of the studied interval. Biostratigraphic data include biozones, benthonic to planktonic ratios, nannofossils and foraminiferal data. Different methods and techniques were applied by using different softwares such as Petrel and Interactive petrophysical software. Four missing times were identified intra-Pleistocene, Late Pliocene, Late Pliocene-Early Pliocene and Messinian. It has concluded that, the depositional environments ranged from shallow marine to middle nerritic and may reach upper bathyal toward the northern part of the study area. The top of Abu Madi Formation dated with the calcareous nannofossils zone NN12a, while the base dated with NN11c, and its age varied from 5.2 Ma to 5.7 Ma. The maximum flooding surface is dated with the calcareous nannofossils zone NN13 and the planktonic foraminiferal zone SN18 at 5 Ma (the acme presence of the Sphaeroidinellopsis sp.). From the utility of wireline logs for sequence stratigraphy using the different log tools for lithological interpretation and their impact upon the reflection characteristics and sequence stratigraphic interpretation, it is concluded the parasequence sets, system tracts, surface boundaries and their distribution within each well and their control on the sand distribution within each formation. In the present work, the Late Miocene (Messinian) and the Early Pliocene (Zanclian) pay-zones are the only rock units, that have integrated wireline logs approach, so it can be divided into 4 sequences; UM-1, UM-2A, UM-2B and LZ-1.

Nasr El-Deen Badawy, A. M.; Abu El-Ata, A. S.; El-Gendy, N. H.

2013-12-01

7

Sequence Stratigraphic Analysis for Delineating the Sedimentation Characteristic and Modeling of Nidoco Area, Off-Shore Nile Delta, Egypt  

NASA Astrophysics Data System (ADS)

The Egyptian Nile Delta has recognized over the different human civilizations, as the source of life/ basket of wheat. In the recent time, the Nile Delta revealed another hidden treasure that hidden below the Mediterranean Sea within its sediments. This treasure reflects a number of giant gas reservoirs that require only the suitable technology and the assured ideas to commence injecting gas into the industrial veins of the growing Egyptian economy. The current study is aiming to discuss the Messinian Prospectivity of the concerned area, which is located in the offshore of the Nile Delta, about 25 Km from the Mediterranean Sea shoreline. An integrated exploration approach applied for a selected area, using a variety of subsurface borehole geologic and log data of the selected wells distributed in the study area, as well as biostratigraphic data. The well data comprise well markers, and electric logs (e.g. gamma ray, density, neutron and sonic logs), where the geological data represented by litho-stratigraphic information, as well as ditch samples analysis of the studied interval. Biostratigraphic data include biozones, benthonic to planktonic ratios, nannofossils and foraminiferal data. Different methods and techniques were applied by using different softwares such as Petrel and Interactive petrophysical software. Four missing times were identified intra-Pleistocene, Late Pliocene, Late Pliocene-Early Pliocene and Messinian. It has concluded that, the depositional environments ranged from shallow marine to middle nerritic and may reach upper bathyal toward the northern part of the study area. The top of Abu Madi Formation dated with the calcareous nannofossils zone NN12a, while the base dated with NN11c, and its age varied from 5.2 Ma to 5.7 Ma. The maximum flooding surface is dated with the calcareous nannofossils zone NN13 and the planktonic foraminiferal zone SN18 at 5 Ma (the acme presence of the Sphaeroidinellopsis sp.). From the utility of wireline logs for sequence stratigraphy using the different log tools for lithological interpretation and their impact upon the reflection characteristics and sequence stratigraphic interpretation, it is concluded the parasequence sets, system tracts, surface boundaries and their distribution within each well and their control on the sand distribution within each formation. In the present work, the Late Miocene (Messinian) and the Early Pliocene (Zanclian) pay-zones are the only rock units, that have integrated wireline logs approach, so it can be divided into 4 sequences; UM-1, UM-2A, UM-2B and LZ-1.

Nasr El Deen, Ahmed; Abu El-Ata, Ahmed; El-Gendy, Nader

2014-05-01

8

Stratigraphic and structural analysis of the Neogene sediments of the offshore portion of the Salina del Istmo Basin, southeastern Mexico  

NASA Astrophysics Data System (ADS)

Southeastern Mexico has been affected by regional and local tectonic events. Regional tectonic events are the Gulf of Mexico opening and the lateral movement of micro-plates on the Pacific margin. The local tectonic events are related to salt tectonics. Autochthonous Jurassic salt serves as the detachment level for the main compressional event in the late Miocene. Jurassic salt was allochthonously emplaced in the late Miocene, then partially displaced by a huge quantity of terrigenous sediments during the Plio-Pleistocene. This research is a study of the main geological processes that have influenced the structural and stratigraphic evolution of the Neogene sediments in the offshore portion of the Salina del Istmo basin known as the Marbella area. Owing to data availability, the project was divided into regional and local studies. The regional study is based on 2D multi-channel seismic reflection data, and the local study is based on a 3D seismic streamer survey. Structural analysis in the regional study permits the recognition of four buried fold belts (Agua Dulce, Catemaco, Marbella, and Marbella Norte) trending roughly NE. These fold belts are the result of tectonic convergence in the pacific margin during late Miocene. The Agua Dulce and Marbella Norte fold belts are separated by an enormous salt withdrawal basin called the Pescadores basin. The Pescadores basin is bounded on the north by a spectacular stepped, counter-regional structure. Beyond the Pescadores basin, a salt mini-basin area is recognized in the upper continental slope. Another important structural element is the Sal Somera canopy in the southern part of the study area. Sedimentation-rate analysis, based on isochore mapping in the local study area, indicates that from SB-2.4 to SB-2.6 Ma, deposition rate peaked with a maximum of 7.5 mm/yr. Regional and local structural restorations show that, in general, the maximum allochthonous salt mobilization was during the Plio-Pleistocene because of the huge quantity of sediments that the Chiapas massif and the Sierra de Chiapas supplied to the basin. A geohistory plot indicates rapid basin deepening at 2.4 to 2.6 Ma, which is attributed to a major influx of sediments and allochthonous salt evacuation.

Gomez-Cabrera, Pedro Tomas

2003-10-01

9

A preliminary guidebook for identifying stratigraphic contacts at the Nevada Test Site  

SciTech Connect

Lithologic variation, regional depositional trends, and the lack of written guidelines have resulted in inconsistencies in the recognition of stratigraphic contacts in drill holes at the Nevada Test Site (NTS). Stratigraphic identification, based on mineralogy of discrete samples, can be augmented by geophysical logs and downhole movies to more accurately and consistently locate contacts between units. Criteria are established for locating the base of the Pahute Mesa ash-flow tuff, the top of the Ammonia Tanks ash-flow tuff, the top of the Ammonia Tanks bedded tuff, and the top and the base of the Rainier Mesa Tuff.

Pawloski, G.A.; McKague, H.L.; Wagoner, J.L. [Lawrence Livermore National Lab., CA (United States); McKinnis, W.B. [Lawrence Livermore National Lab., Mercury, NV (United States)

1992-01-01

10

Thermometric well testing on the Vietnam offshore  

SciTech Connect

It is impossible to control and adjust an oil and gas field development without determining the flow intervals of production wells. For that it is preferable to get production profiles by using the downhole flowmeter. There are, however, some main restrictions for wide-spread application of them on the offshore of Vietnam as follows: the flowmeter spinner velocity cannot indicate correctly in the open hole wells having a nonuniform diameter; it is unable to carry out in the case when the tubing shoe is lower than top formation on 300--500m. In this paper, the authors present a summary of temperature profile method to determine the flowing and intaking intervals of wells drilled in basement of the White Tiger Field on Vietnam offshore. For the last 2 years more than 30 wells were surveyed by this method in the above mentioned conditions. This paper presents the theory and practice of well temperature profile surveys, the concrete examples of data interpretation using the software Oiltest.

San, T.N.; Shtyrlin, V.F.; Vakhitov, G.G.; Loi, L.M.; Listengarten, L.; Hien, D.L.

1994-12-31

11

Gas production from a cold, stratigraphically-bounded gas hydrate deposit at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Implications of uncertainties  

USGS Publications Warehouse

As part of an effort to identify suitable targets for a planned long-term field test, we investigate by means of numerical simulation the gas production potential from unit D, a stratigraphically bounded (Class 3) permafrost-associated hydrate occurrence penetrated in the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well on North Slope, Alaska. This shallow, low-pressure deposit has high porosities (?? = 0.4), high intrinsic permeabilities (k = 10-12 m2) and high hydrate saturations (SH = 0.65). It has a low temperature (T = 2.3-2.6 ??C) because of its proximity to the overlying permafrost. The simulation results indicate that vertical wells operating at a constant bottomhole pressure would produce at very low rates for a very long period. Horizontal wells increase gas production by almost two orders of magnitude, but production remains low. Sensitivity analysis indicates that the initial deposit temperature is by the far the most important factor determining production performance (and the most effective criterion for target selection) because it controls the sensible heat available to fuel dissociation. Thus, a 1 ??C increase in temperature is sufficient to increase the production rate by a factor of almost 8. Production also increases with a decreasing hydrate saturation (because of a larger effective permeability for a given k), and is favored (to a lesser extent) by anisotropy. ?? 2010.

Moridis, G.J.; Silpngarmlert, S.; Reagan, M.T.; Collett, T.; Zhang, K.

2011-01-01

12

Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Overview of scientific and technical program  

USGS Publications Warehouse

The Mount Elbert Gas Hydrate Stratigraphic Test Well was drilled within the Alaska North Slope (ANS) Milne Point Unit (MPU) from February 3 to 19, 2007. The well was conducted as part of a Cooperative Research Agreement (CRA) project co-sponsored since 2001 by BP Exploration (Alaska), Inc. (BPXA) and the U.S. Department of Energy (DOE) in collaboration with the U.S. Geological Survey (USGS) to help determine whether ANS gas hydrate can become a technically and commercially viable gas resource. Early in the effort, regional reservoir characterization and reservoir simulation modeling studies indicated that up to 0.34 trillion cubic meters (tcm; 12 trillion cubic feet, tcf) gas may be technically recoverable from 0.92 tcm (33 tcf) gas-in-place within the Eileen gas hydrate accumulation near industry infrastructure within ANS MPU, Prudhoe Bay Unit (PBU), and Kuparuk River Unit (KRU) areas. To further constrain these estimates and to enable the selection of a test site for further data acquisition, the USGS reprocessed and interpreted MPU 3D seismic data provided by BPXA to delineate 14 prospects containing significant highly-saturated gas hydrate-bearing sand reservoirs. The "Mount Elbert" site was selected to drill a stratigraphic test well to acquire a full suite of wireline log, core, and formation pressure test data. Drilling results and data interpretation confirmed pre-drill predictions and thus increased confidence in both the prospect interpretation methods and in the wider ANS gas hydrate resource estimates. The interpreted data from the Mount Elbert well provide insight into and reduce uncertainty of key gas hydrate-bearing reservoir properties, enable further refinement and validation of the numerical simulation of the production potential of both MPU and broader ANS gas hydrate resources, and help determine viability of potential field sites for future extended term production testing. Drilling and data acquisition operations demonstrated that gas hydrate scientific research programs can be safely, effectively, and efficiently conducted within ANS infrastructure. The program success resulted in a technical team recommendation to project management to drill and complete a long-term production test within the area of existing ANS infrastructure. If approved by stakeholders, this long-term test would build on prior arctic research efforts to better constrain the potential gas rates and volumes that could be produced from gas hydrate-bearing sand reservoirs. ?? 2010 Elsevier Ltd.

Hunter, R.B.; Collett, T.S.; Boswell, R.; Anderson, B.J.; Digert, S.A.; Pospisil, G.; Baker, R.; Weeks, M.

2011-01-01

13

Pore fluid geochemistry from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

USGS Publications Warehouse

The BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well was drilled and cored from 606.5 to 760.1. m on the North Slope of Alaska, to evaluate the occurrence, distribution and formation of gas hydrate in sediments below the base of the ice-bearing permafrost. Both the dissolved chloride and the isotopic composition of the water co-vary in the gas hydrate-bearing zones, consistent with gas hydrate dissociation during core recovery, and they provide independent indicators to constrain the zone of gas hydrate occurrence. Analyses of chloride and water isotope data indicate that an observed increase in salinity towards the top of the cored section reflects the presence of residual fluids from ion exclusion during ice formation at the base of the permafrost layer. These salinity changes are the main factor controlling major and minor ion distributions in the Mount Elbert Well. The resulting background chloride can be simulated with a one-dimensional diffusion model, and the results suggest that the ion exclusion at the top of the cored section reflects deepening of the permafrost layer following the last glaciation (???100 kyr), consistent with published thermal models. Gas hydrate saturation values estimated from dissolved chloride agree with estimates based on logging data when the gas hydrate occupies more than 20% of the pore space; the correlation is less robust at lower saturation values. The highest gas hydrate concentrations at the Mount Elbert Well are clearly associated with coarse-grained sedimentary sections, as expected from theoretical calculations and field observations in marine and other arctic sediment cores. ?? 2009 Elsevier Ltd.

Torres, M.E.; Collett, T.S.; Rose, K.K.; Sample, J.C.; Agena, W.F.; Rosenbaum, E.J.

2011-01-01

14

The characteristics of gas hydrates recovered from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

Microsoft Academic Search

Systematic analyses have been carried out on two gas hydrate-bearing sediment core samples, HYPV4, which was preserved by CH4 gas pressurization, and HYLN7, which was preserved in liquid-nitrogen, recovered from the BPXA-DOE-USGS Mount Elbert Stratigraphic Test Well. Gas hydrate in the studied core samples was found by observation to have developed in sediment pores, and the distribution of hydrate saturation

Hailong Lu; Thomas D. Lorenson; Igor L. Moudrakovski; John A. Ripmeester; Timothy S. Collett; Robert B. Hunter; Chris I. Ratcliffe

2011-01-01

15

Testing Stratigraphic Integrity of Upper and Middle Paleolithic Deposits in Vindija Cave (Croatia): A Chipped Stone Refitting Analysis  

E-print Network

as the Middle-Upper Paleolithic transition. 30 Lithic Materials Lithic materials utilized in the production of stone tools at Vindija include quartz, quartzite, chert, tuf, basalt, and other unidentified siliceous rocks exhibiting paterns of concoidal... TESTING STRATIGRAPHIC INTEGRITY OF UPER AND MIDLE PALEOLITHIC DEPOSITS IN VINDIJA CAVE (CROATIA): A Chiped Stone Refiting Analysis By Kale M. Bruner B. A. University of Kansas, 2002 Submited to the Department of Anthropology...

Bruner, Kale

2009-05-12

16

Effects of Offshore Sampling and Testing on Undrained Soil Shear Strength  

Microsoft Academic Search

The empirical procedures for offshore foundations design are directly influenced by the shear strength values selected for analyses. There is generally a large amount of scatter in measured undrained shear strength data from offshore borings because of various types of laboratory tests and sample disturbance. A comparison of strength data obtained on samples of cohesive soils from the Gulf of

A. G. Young; G. Quiros; C. Ehlers

1983-01-01

17

Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

USGS Publications Warehouse

This study characterizes cored and logged sedimentary strata from the February 2007 BP Exploration Alaska, Department of Energy, U.S. Geological Survey (BPXA-DOE-USGS) Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope (ANS). The physical-properties program analyzed core samples recovered from the well, and in conjunction with downhole geophysical logs, produced an extensive dataset including grain size, water content, porosity, grain density, bulk density, permeability, X-ray diffraction (XRD) mineralogy, nuclear magnetic resonance (NMR), and petrography. This study documents the physical property interrelationships in the well and demonstrates their correlation with the occurrence of gas hydrate. Gas hydrate (GH) occurs in three unconsolidated, coarse silt to fine sand intervals within the Paleocene and Eocene beds of the Sagavanirktok Formation: Unit D-GH (614.4 m-627.9 m); unit C-GH1 (649.8 m-660.8 m); and unit C-GH2 (663.2 m-666.3 m). These intervals are overlain by fine to coarse silt intervals with greater clay content. A deeper interval (unit B) is similar lithologically to the gas-hydrate-bearing strata; however, it is water-saturated and contains no hydrate. In this system it appears that high sediment permeability (k) is critical to the formation of concentrated hydrate deposits. Intervals D-GH and C-GH1 have average "plug" intrinsic permeability to nitrogen values of 1700 mD and 675 mD, respectively. These values are in strong contrast with those of the overlying, gas-hydrate-free sediments, which have k values of 5.7 mD and 49 mD, respectively, and thus would have provided effective seals to trap free gas. The relation between permeability and porosity critically influences the occurrence of GH. For example, an average increase of 4% in porosity increases permeability by an order of magnitude, but the presence of a second fluid (e.g., methane from dissociating gas hydrate) in the reservoir reduces permeability by more than an order of magnitude.

Winters, William J.; Walker, Michael; Hunter, Robert; Collett, Timothy S.; Boswell, Ray M.; Rose, Kelly K.; Waite, William F.; Torres, Marta; Patil, Shirish; Dandekar, Abhijit

2011-01-01

18

Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

USGS Publications Warehouse

This study characterizes cored and logged sedimentary strata from the February 2007 BP Exploration Alaska, Department of Energy, U.S. Geological Survey (BPXA-DOE-USGS) Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope (ANS). The physical-properties program analyzed core samples recovered from the well, and in conjunction with downhole geophysical logs, produced an extensive dataset including grain size, water content, porosity, grain density, bulk density, permeability, X-ray diffraction (XRD) mineralogy, nuclear magnetic resonance (NMR), and petrography.This study documents the physical property interrelationships in the well and demonstrates their correlation with the occurrence of gas hydrate. Gas hydrate (GH) occurs in three unconsolidated, coarse silt to fine sand intervals within the Paleocene and Eocene beds of the Sagavanirktok Formation: Unit D-GH (614.4. m-627.9. m); unit C-GH1 (649.8. m-660.8. m); and unit C-GH2 (663.2. m-666.3. m). These intervals are overlain by fine to coarse silt intervals with greater clay content. A deeper interval (unit B) is similar lithologically to the gas-hydrate-bearing strata; however, it is water-saturated and contains no hydrate.In this system it appears that high sediment permeability (k) is critical to the formation of concentrated hydrate deposits. Intervals D-GH and C-GH1 have average "plug" intrinsic permeability to nitrogen values of 1700 mD and 675 mD, respectively. These values are in strong contrast with those of the overlying, gas-hydrate-free sediments, which have k values of 5.7. mD and 49 mD, respectively, and thus would have provided effective seals to trap free gas. The relation between permeability and porosity critically influences the occurrence of GH. For example, an average increase of 4% in porosity increases permeability by an order of magnitude, but the presence of a second fluid (e.g., methane from dissociating gas hydrate) in the reservoir reduces permeability by more than an order of magnitude. ?? 2010.

Winters, W.; Walker, M.; Hunter, R.; Collett, T.; Boswell, R.; Rose, K.; Waite, W.; Torres, M.; Patil, S.; Dandekar, A.

2011-01-01

19

Automatic picking and attribute mapping for a quick evaluation of the potential of turbiditic sands and stratigraphic traps in frontier areas. An example from the deep offshore of the Niger Delta  

SciTech Connect

Most interpretation teams involved in the exploration of Nigeria's deep offshore have been faced with a major challenge: (1) how to scan through a large volume of 3D data in a drastically short time frame... (2) with the captive of understanding the depositional pattern of slope fan and basin floor fan turbidites to identify mostly stratigraphic traps... (3) in an environment almost devoid of reference wells and calibration. A traditional approach was likely to miss both the deadlines and the sensitivity required for the sedimentological aspects of the study. Elfs answer was to rely extensively on the advanced functionalities of the SISMAGE (TM) workstation, in order to quickly generate time and seismic attribute maps which could then be interpreted in terms of structure and sedimentology. Two critical aspects were particularly well handled by the workstation: (1) the reliability of the extrapolation process from a loose grid of manually picked lines, and (2) the generation of seismic attribute maps relative not only to surfaces (e.g. sequence boundaries), but also to whole intervals through statistical calculation. In a second stage, the interpreters were able to focus on the most prospective areas and to move on to prospect generation, with the help of AVO studies. This approach is illustrated through an example from the deep offshore of the Niger delta.

Montagnier, P.; Rossi, T. (Elf Nigeria, Lagos (Nigeria)); Clergeat, B.; Dall'astam, W.F. (Elf Aquitaine Production, Paris (France))

1996-01-01

20

Automatic picking and attribute mapping for a quick evaluation of the potential of turbiditic sands and stratigraphic traps in frontier areas. An example from the deep offshore of the Niger Delta  

SciTech Connect

Most interpretation teams involved in the exploration of Nigeria`s deep offshore have been faced with a major challenge: (1) how to scan through a large volume of 3D data in a drastically short time frame... (2) with the captive of understanding the depositional pattern of slope fan and basin floor fan turbidites to identify mostly stratigraphic traps... (3) in an environment almost devoid of reference wells and calibration. A traditional approach was likely to miss both the deadlines and the sensitivity required for the sedimentological aspects of the study. Elfs answer was to rely extensively on the advanced functionalities of the SISMAGE (TM) workstation, in order to quickly generate time and seismic attribute maps which could then be interpreted in terms of structure and sedimentology. Two critical aspects were particularly well handled by the workstation: (1) the reliability of the extrapolation process from a loose grid of manually picked lines, and (2) the generation of seismic attribute maps relative not only to surfaces (e.g. sequence boundaries), but also to whole intervals through statistical calculation. In a second stage, the interpreters were able to focus on the most prospective areas and to move on to prospect generation, with the help of AVO studies. This approach is illustrated through an example from the deep offshore of the Niger delta.

Montagnier, P.; Rossi, T. [Elf Nigeria, Lagos (Nigeria); Clergeat, B.; Dall`astam, W.F. [Elf Aquitaine Production, Paris (France)

1996-12-31

21

Offshore suspensions plume deposit as a stratigraphic signature of catastrophic river floods during the last 500 years: the case of the Amalfi coast  

NASA Astrophysics Data System (ADS)

The Amalfi coast is a segment of the southern slope of the Sorrento Peninsula, a narrow and elevated mountain range (up to 1444 m) along the SW coastal zone of Italy. The Peninsula is deeply cut by a complex of bedrock rivers and channels characterized by relatively high energy of the relief, small catchment areas and pronounced disequilibrium of the stream profiles. There is evidence suggesting that the dynamic regime of the alluvial fans and associated fan-deltas of the Amalfi coast are controlled by episodic, but often catastrophic sediment and water discharges that have caused repeated flooding of the fans and accumulation of large volumes of sediment in the fan-deltas over last centuries. Documentary source materials show that, since the 16th century, at least 106 severe floods occurred over the Amalfi coast. The most dramatic episodes occurred between XVI and XX centuries (1581, 1588, 1773, 1899, 1954 events), caused severe geomorphologic change, damage to buildings and a high number of victims. The flood events triggered landslide, mud flow, debris flow and rock falls phenomena as well as denudation and erosion upstream. This research is based on the of stratigraphic study of marine gravity cores, and high-resolution seismic profiles acquired in the fan-delta deposits that develop at the mouth of the hydrographic system of the Amalfi coast. Particularly, the integrated stratigraphic analysis of prodelta deposits, shows that there is a consistent correlation between documental evidence of historical catastrophic floodings and the occurrence of individual layers or claster of (2-3 cm thick) layers of suspension deposit associated with sustained hyperpycnal plumes (underflows) within the fan-delta sequence. The identification of suspension plume deposits, within fan-delta deposits off the cliffed Amalfi coasts, may thus be regarded as a useful tool in order to explore the occurrence of major flooding episodes back to stratigraphic record of the Late Holocene.

Molisso, Flavia; Esposito, Eliana; Porfido, Sabina; Sacchi, Marco; Violante, Crescenzo

2010-05-01

22

High resolution sequence stratigraphic and reservoir characterization studies of D-07, D-08 and E-01 sands, Block 2 Meren field, offshore Niger Delta  

E-print Network

- to fine-grained poorly-sorted sandstone (delta front facies); (5) muddy silt-to fine- grained wavy-bedded sandstone (lower shoreface facies); (6) very-fine- to fine-grained iv sandy mudstone (lower shoreface facies); and (7) massive, silty shales.... The progradational parasequence set consists of upward-coarsening delta front to upper shoreface facies, whereas the upward- fining retrogradational parasequence sets are composed of middle to lower shoreface deposits overlain by offshore marine shales...

Esan, Adegbenga Oluwafemi

2004-09-30

23

Cenozoic synthem stratigraphic architecture of the SE Brazilian shelf and its global eustatic context: evidence from the Pelotas Basin (offshore Brazil)  

NASA Astrophysics Data System (ADS)

The Pelotas Basin, located on the SE Brazilian shelf, has evolved since the Aptian. Stratigraphical data from the basin can be used for delineation of the unconformity-bounded units (synthems) on the shelf, which is a first step towards a full understanding of its stratigraphic architecture, evolution, and hydrocarbon potential. Hiatuses in the Cenozoic succession of the Pelotas Basin are established with both biostratigraphic (planktonic foraminifers and calcareous nannofossils) and isotopic (87Sr/86Sr) data. The seven recognised hiatuses are dated respectively as (1) Palaeocene (Danian- Thanetian), (2) Palaeocene/Eocene boundary (Thanetian-Ypresian), (3) Eocene (Ypresian-Lutetian), (4) Eocene-Oligocene (Lutetian-Rupelian), (5) early-late Oligocene (Rupelian-Chattian), (6) early Miocene (Aquitanian-Burdigalian), and (7) middle-late Miocene (Serravallian-Tortonian). These intervals between the hiatuses are correlated with those of the Santos and Campos Basins north from the Pelotas Basin. The breaks in sedimentation that these basins have in common occurred (1) at the Palaeocene-Eocene and (2) Eocene-Oligocene transitions, (3) in the early Miocene, and (4) in the middle-late Miocene. These main unconformities outline five synthems on the SE Brazilian shelf, viz. the SEBS-1 (Palaeocene), SEBS-2 (Eocene), SEBS-3 (Oligocene), SEBS-4 (early-middle Miocene) and SEBS-5 (late Miocene-Holocene). The above unconformities are correlated with those established in the Cenozoic sedimentary successions of different regions such as Western Siberia, Arabia, NW and NE Africa, peninsular India, S Australia, the Gulf of Mexico, NW Europe, and South Africa. The only regional unconformity, near the Oligocene/Miocene boundary, coincides with the nearly-global sedimentation break. The latter was resulted from a climatic event, i.e., the `Mi-1 glaciation'. Thus, a eustatic origin is supposed for this regional unconformity. The other regional unconformities also correspond to global sea-level falls (probably with an exception for the Palaeocene/Eocene surface), which suggests that global eustatic movements controlled the development of the regional synthem architecture.

de Santana dos Anjos Zerfass, Geise; Ruban, Dmitry A.; Chemale, Farid, Jr.; Zerfass, Henrique

2013-12-01

24

FIELD TEST KIT FOR CHARACTERIZING OIL-BRINE EFFLUENTS FROM OFFSHORE DRILLING PLATFORMS  

EPA Science Inventory

This research program was initiated to evaluate test methods for characterizing oil-brine effluents from offshore oil production platforms and to package and deliver a field test kit for on-site oil-brine analyses. After an initial laboratory evaluation and selection of test meth...

25

Downhole well log and core montages from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

USGS Publications Warehouse

The BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well was an integral part of an ongoing project to determine the future energy resource potential of gas hydrates on the Alaska North Slope. As part of this effort, the Mount Elbert well included an advanced downhole geophysical logging program. Because gas hydrate is unstable at ground surface pressure and temperature conditions, a major emphasis was placed on the downhole-logging program to determine the occurrence of gas hydrates and the in-situ physical properties of the sediments. In support of this effort, well-log and core data montages have been compiled which include downhole log and core-data obtained from the gas-hydrate-bearing sedimentary section in the Mount Elbert well. Also shown are numerous reservoir parameters, including gas-hydrate saturation and sediment porosity log traces calculated from available downhole well log and core data. ?? 2010.

Collett, T.S.; Lewis, R.E.; Winters, W.J.; Lee, M.W.; Rose, K.K.; Boswell, R.M.

2011-01-01

26

Investigation of gas hydrate-bearing sandstone reservoirs at the "Mount Elbert" stratigraphic test well, Milne Point, Alaska  

SciTech Connect

In February 2007, the U.S. Department of Energy, BP Exploration (Alaska), Inc., and the U.S. Geological Survey conducted an extensive data collection effort at the "Mount Elbert #1" gas hydrates stratigraphic test well on the Alaska North Slope (ANS). The 22-day field program acquired significant gas hydrate-bearing reservoir data, including a full suite of open-hole well logs, over 500 feet of continuous core, and open-hole formation pressure response tests. Hole conditions, and therefore log data quality, were excellent due largely to the use of chilled oil-based drilling fluids. The logging program confirmed the existence of approximately 30 m of gashydrate saturated, fine-grained sand reservoir. Gas hydrate saturations were observed to range from 60% to 75% largely as a function of reservoir quality. Continuous wire-line coring operations (the first conducted on the ANS) achieved 85% recovery through 153 meters of section, providing more than 250 subsamples for analysis. The "Mount Elbert" data collection program culminated with open-hole tests of reservoir flow and pressure responses, as well as gas and water sample collection, using Schlumberger's Modular Formation Dynamics Tester (MDT) wireline tool. Four such tests, ranging from six to twelve hours duration, were conducted. This field program demonstrated the ability to safely and efficiently conduct a research-level openhole data acquisition program in shallow, sub-permafrost sediments. The program also demonstrated the soundness of the program's pre-drill gas hydrate characterization methods and increased confidence in gas hydrate resource assessment methodologies for the ANS.

Boswell, R.M.; Hunter, R. (ASRC Energy Services, Anchorage, AK); Collett, T. (USGS, Denver, CO); Digert, S. (BP Exploration (Alaska) Inc., Anchorage, AK); Hancock, S. (RPS Energy Canada, Calgary, Alberta, Canada); Weeks, M. (BP Exploration (Alaska) Inc., Anchorage, AK); Mt. Elbert Science Team

2008-01-01

27

Grid Simulator for Testing a Wind Turbine on Offshore Floating Platform  

SciTech Connect

An important aspect of such offshore testing of a wind turbine floating platform is electrical loading of the wind turbine generator. An option of interconnecting the floating wind turbine with the onshore grid via submarine power cable is limited by many factors such as costs and associated environmental aspects (i.e., an expensive and lengthy sea floor study is needed for cable routing, burial, etc). It appears to be a more cost effective solution to implement a standalone grid simulator on a floating platform itself for electrical loading of the test wind turbine. Such a grid simulator must create a stable fault-resilient voltage and frequency bus (a micro grid) for continuous operation of the test wind turbine. In this report, several electrical topologies for an offshore grid simulator were analyzed and modeled.

Gevorgian, V.

2012-02-01

28

Examination of core samples from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Effects of retrieval and preservation  

Microsoft Academic Search

Collecting and preserving undamaged core samples containing gas hydrates from depth is difficult because of the pressure and temperature changes encountered upon retrieval. Hydrate-bearing core samples were collected at the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well in February 2007. Coring was performed while using a custom oil-based drilling mud, and the cores were retrieved by a wireline. The

Timothy J. Kneafsey; Hailong Lu; William Winters; Ray Boswell; Robert Hunter; Timothy S. Collett

2011-01-01

29

Formation pressure testing at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Operational summary, history matching, and interpretations  

USGS Publications Warehouse

In February 2007, the U.S. Department of Energy, BP Exploration (Alaska), and the U.S. Geological Survey, collected open-hole pressure-response data, as well as gas and water sample collection, in a gas hydrate reservoir (the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well) using Schlumberger's Modular Dynamics Formation Tester (MDT) wireline tool. Four such MDT tests, ranging from six to twelve hours duration, and including a series of flow, sampling, and shut-in periods of various durations, were conducted. Locations for the testing were selected based on NMR and other log data to assure sufficient isolation from reservoir boundaries and zones of excess free water. Test stages in which pressure was reduced sufficiently to mobilize free water in the formation (yet not cause gas hydrate dissociation) produced readily interpretable pressure build-up profiles. Build-ups following larger drawdowns consistently showed gas-hydrate dissociation and gas release (as confirmed by optical fluid analyzer data), as well as progressive dampening of reservoir pressure build-up during sequential tests at a given MDT test station.History matches of one multi-stage, 12-h test (the C2 test) were accomplished using five different reservoir simulators: CMG-STARS, HydrateResSim, MH21-HYDRES, STOMP-HYD, and TOUGH. +. HYDRATE. Simulations utilized detailed information collected across the reservoir either obtained or determined from geophysical well logs, including thickness (11.3. m, 37 ft.), porosity (35%), hydrate saturation (65%), both mobile and immobile water saturations, intrinsic permeability (1000 mD), pore water salinity (5 ppt), and formation temperature (3.3-3.9 ??C). This paper will present the approach and preliminary results of the history-matching efforts, including estimates of initial formation permeability and analyses of the various unique features exhibited by the MDT results. ?? 2010 Elsevier Ltd.

Anderson, B.; Hancock, S.; Wilson, S.; Enger, C.; Collett, T.; Boswell, R.; Hunter, R.

2011-01-01

30

An Empirical Investigation of Client Managers’ Responsibilities in Managing Offshore Outsourcing of Software-Testing Projects  

Microsoft Academic Search

Despite an increase in the offshore outsourcing of in- formation technology (IT) projects, little research has been carried out to identify issues that client managers (CMs) encounter when managing projects with offshore vendors. Also research on how CMs' responsibilities change to effectively manage offshore out- sourcing relationships has received little attention. We conducted a case study of an offshore outsourcing

Radhika P. Jain; Robin S. Poston; Judith C. Simon

2011-01-01

31

Extensional tectonics, halokinesis, eustacy in the Norwegian Central Graben, North Sea: A testing ground for sequence and seismic stratigraphic principles  

SciTech Connect

The Norwegian Central Graben is a mature hydrocarbon province with proven reserves within the Upper Jurassic succession. Several phases of extensional tectonics ranging from the Permo-Triassic to the Upper Jurassic, and a thick mobile salt section, serve to complicate a clear regional understanding of the area. A full integration of structural interpretation, seismic and sequence stratigraphic principles, biostratigraphy and core studies is required to achieve a realistic interpretation and predict Upper Jurassic facies distributions within this complex area. Utilizing some 30 wells, regional seismic data and biostratigraphy, candidate sequence boundaries and regionally correlatable flooding surfaces (e.g. Eudoxus), have been identified. Horizon flattening on these surfaces has allowed the recognition of thickening-away reflection geometries adjacent to salt features and divergent geometries into graben boundary faults. This facilitates the identification of the dominant local or regional controls on accommodation space creation. Detailed seismic facies analysis was then used to reveal the relative expansion or suppression of depositional systems tracts as a response to either regional or local structural controls. It was subsequently possible to place these systems within a biostratigraphically constrained regional framework. Mapping the base Zechstein, base Jurassic and base Cretaceous horizons has provided a map view of the active faults and slopes controlling sediment transport at any given time. This provided the third dimension essential in depicting the spatial distribution of depositional systems, and is a crucial component of any sequence stratigraphic interpretation. A regional picture of the progressive evolution of this complex area has been thus been derived, and the effect of both regional and local controls on sequence stratigraphic expressions has been determined.

Spencer, P.A. [Oxford Brookes Univ. (United Kingdom); Prosser, S.D. [Saga Petroleum a.s., Sandvika (Norway)

1996-12-31

32

Extensional tectonics, halokinesis, eustacy in the Norwegian Central Graben, North Sea: A testing ground for sequence and seismic stratigraphic principles  

SciTech Connect

The Norwegian Central Graben is a mature hydrocarbon province with proven reserves within the Upper Jurassic succession. Several phases of extensional tectonics ranging from the Permo-Triassic to the Upper Jurassic, and a thick mobile salt section, serve to complicate a clear regional understanding of the area. A full integration of structural interpretation, seismic and sequence stratigraphic principles, biostratigraphy and core studies is required to achieve a realistic interpretation and predict Upper Jurassic facies distributions within this complex area. Utilizing some 30 wells, regional seismic data and biostratigraphy, candidate sequence boundaries and regionally correlatable flooding surfaces (e.g. Eudoxus), have been identified. Horizon flattening on these surfaces has allowed the recognition of thickening-away reflection geometries adjacent to salt features and divergent geometries into graben boundary faults. This facilitates the identification of the dominant local or regional controls on accommodation space creation. Detailed seismic facies analysis was then used to reveal the relative expansion or suppression of depositional systems tracts as a response to either regional or local structural controls. It was subsequently possible to place these systems within a biostratigraphically constrained regional framework. Mapping the base Zechstein, base Jurassic and base Cretaceous horizons has provided a map view of the active faults and slopes controlling sediment transport at any given time. This provided the third dimension essential in depicting the spatial distribution of depositional systems, and is a crucial component of any sequence stratigraphic interpretation. A regional picture of the progressive evolution of this complex area has been thus been derived, and the effect of both regional and local controls on sequence stratigraphic expressions has been determined.

Spencer, P.A. (Oxford Brookes Univ. (United Kingdom)); Prosser, S.D. (Saga Petroleum a.s., Sandvika (Norway))

1996-01-01

33

Shaking table test and numerical analysis of offshore wind turbine tower systems controlled by TLCD  

NASA Astrophysics Data System (ADS)

A wind turbine system equipped with a tuned liquid column damper (TLCD) is comprehensively studied via shaking table tests using a 1/13-scaled model. The effects of wind and wave actions are considered by inputting response-equivalent accelerations on the shaking table. The test results show that the control effect of the TLCD system is significant in reducing the responses under both wind-wave equivalent loads and ground motions, but obviously varies for different inputs. Further, a blade-hub-tower integrated numerical model for the wind turbine system is established. The model is capable of considering the rotational effect of blades by combining Kane's equation with the finite element method. The responses of the wind tower equipped with TLCD devices are numerically obtained and compared to the test results, showing that under both controlled and uncontrolled conditions with and without blades' rotation, the corresponding responses exhibit good agreement. This demonstrates that the proposed numerical model performs well in capturing the wind-wave coupled response of the offshore wind turbine systems under control. Both numerical and experimental results show that the TLCD system can significantly reduce the structural response and thus improve the safety and serviceability of the offshore wind turbine tower systems. Additional issues that require further study are discussed.

Chen, Jianbing; Liu, Youkun; Bai, Xueyuan

2015-03-01

34

Efficient preliminary floating offshore wind turbine design and testing methodologies and application to a concrete spar design.  

PubMed

The current key challenge in the floating offshore wind turbine industry and research is on designing economic floating systems that can compete with fixed-bottom offshore turbines in terms of levelized cost of energy. The preliminary platform design, as well as early experimental design assessments, are critical elements in the overall design process. In this contribution, a brief review of current floating offshore wind turbine platform pre-design and scaled testing methodologies is provided, with a focus on their ability to accommodate the coupled dynamic behaviour of floating offshore wind systems. The exemplary design and testing methodology for a monolithic concrete spar platform as performed within the European KIC AFOSP project is presented. Results from the experimental tests compared to numerical simulations are presented and analysed and show very good agreement for relevant basic dynamic platform properties. Extreme and fatigue loads and cost analysis of the AFOSP system confirm the viability of the presented design process. In summary, the exemplary application of the reduced design and testing methodology for AFOSP confirms that it represents a viable procedure during pre-design of floating offshore wind turbine platforms. PMID:25583870

Matha, Denis; Sandner, Frank; Molins, Climent; Campos, Alexis; Cheng, Po Wen

2015-02-28

35

Regional long-term production modeling from a single well test, Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

SciTech Connect

Following the results from the open-hole formation pressure response test in the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well (Mount Elbert well) using Schlumberger’s Modular Dynamics Formation Tester (MDT) wireline tool, the International Methane Hydrate Reservoir Simulator Code Comparison project performed long-term reservoir simulations on three different model reservoirs. These descriptions were based on 1) the Mount Elbert gas hydrate accumulation as delineated by an extensive history-matching exercise, 2) an estimation of the hydrate accumulation near the Prudhoe Bay L-pad, and 3) a reservoir that would be down-dip of the Prudhoe Bay L-pad and therefore warmer and deeper. All of these simulations were based, in part, on the results of the MDT results from the Mount Elbert Well. The comparison group’s consensus value for the initial perme- ability of the hydrate-filled reservoir (k = 0.12 mD) and the permeability model based on the MDT history match were used as the basis for subsequent simulations on the three regional scenarios. The simulation results of the five different simulation codes, CMG STARS, HydrateResSim, MH-21 HYDRES, STOMP-HYD, and TOUGHþHYDRATE exhibit good qualitative agreement and the variability of potential methane production rates from gas hydrate reservoirs is illustrated. As expected, the pre- dicted methane production rate increased with increasing in situ reservoir temperature; however, a significant delay in the onset of rapid hydrate dissociation is observed for a cold, homogeneous reservoir and it is found to be repeatable. The inclusion of reservoir heterogeneity in the description of this cold reservoir is shown to eliminate this delayed production. Overall, simulations utilized detailed information collected across the Mount Elbert reservoir either obtained or determined from geophysical well logs, including thickness (37 ft), porosity (35%), hydrate saturation (65%), intrinsic permeability (1000 mD), pore water salinity (5 ppt), and formation temperature (3.3–3.9 ?C). This paper presents the approach and results of extrapolating regional forward production modeling from history-matching efforts on the results from a single well test.

Anderson, Brian; Kurihara, Masanori; White, Mark D.; Moridis, George J.; Wilson, Scott J.; Pooladi-Darvish, Mehran; Gaddipati, Manohar; Masuda, Yoshihiro; Collett, T. S.; Hunter, Robert B.; Narita, Hideo; Rose, Kelly K.; Boswell, Ray

2011-02-02

36

Teaching with Stratigraphic Profiles  

ERIC Educational Resources Information Center

Presents two exercises modeled after the ice age puzzle described in the ESCP textbook, including formation of terminal moraines and kettle lakes and intersection of normal faults with gold-quartz veins. Indicates that the stratigraphic profiles are usable in teaching earth science, geography, general science, and topographic problems. (CC)

Stefanich, Greg P.

1974-01-01

37

Summary of Conclusions and Recommendations Drawn from the DeepCWind Scaled Floating Offshore Wind System Test Campaign: Preprint  

SciTech Connect

The DeepCwind consortium is a group of universities, national labs, and companies funded under a research initiative by the U.S. Department of Energy (DOE) to support the research and development of floating offshore wind power. The two main objectives of the project are to better understand the complex dynamic behavior of floating offshore wind systems and to create experimental data for use in validating the tools used in modeling these systems. In support of these objectives, the DeepCwind consortium conducted a model test campaign in 2011 of three generic floating wind systems, a tension-leg platform (TLP), a spar-buoy (spar), and a semisubmersible (semi). Each of the three platforms was designed to support a 1/50th-scale model of a 5 MW wind turbine and was tested under a variety of wind/wave conditions. The focus of this paper is to summarize the work done by consortium members in analyzing the data obtained from the test campaign and its use for validating the offshore wind modeling tool, FAST.

Robertson, A. N.; Jonkman, J. M.; Masciola, M. D.; Molta, P.; Goupee, A. J.; Coulling, A. J.; Prowell, I.; Browning, J.

2013-07-01

38

Gas hydrate characterization and grain-scale imaging of recovered cores from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

USGS Publications Warehouse

Using cryogenic scanning electron microscopy (CSEM), powder X-ray diffraction, and gas chromatography methods, we investigated the physical states, grain characteristics, gas composition, and methane isotopic composition of two gas-hydrate-bearing sections of core recovered from the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well situated on the Alaska North Slope. The well was continuously cored from 606.5. m to 760.1. m depth, and sections investigated here were retrieved from 619.9. m and 661.0. m depth. X-ray analysis and imaging of the sediment phase in both sections shows it consists of a predominantly fine-grained and well-sorted quartz sand with lesser amounts of feldspar, muscovite, and minor clays. Cryogenic SEM shows the gas-hydrate phase forming primarily as a pore-filling material between the sediment grains at approximately 70-75% saturation, and more sporadically as thin veins typically several tens of microns in diameter. Pore throat diameters vary, but commonly range 20-120 microns. Gas chromatography analyses of the hydrate-forming gas show that it is comprised of mainly methane (>99.9%), indicating that the gas hydrate is structure I. Here we report on the distribution and articulation of the gas-hydrate phase within the cores, the grain morphology of the hydrate, the composition of the sediment host, and the composition of the hydrate-forming gas. ?? 2009.

Stern, L.A.; Lorenson, T.D.; Pinkston, J.C.

2011-01-01

39

Gas hydrate characterization and grain-scale imaging of recovered cores from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

USGS Publications Warehouse

Using cryogenic scanning electron microscopy (CSEM), powder X-ray diffraction, and gas chromatography methods, we investigated the physical states, grain characteristics, gas composition, and methane isotopic composition of two gas-hydrate-bearing sections of core recovered from the BPXA–DOE–USGS Mount Elbert Gas Hydrate Stratigraphic Test Well situated on the Alaska North Slope. The well was continuously cored from 606.5 m to 760.1 m depth, and sections investigated here were retrieved from 619.9 m and 661.0 m depth. X-ray analysis and imaging of the sediment phase in both sections shows it consists of a predominantly fine-grained and well-sorted quartz sand with lesser amounts of feldspar, muscovite, and minor clays. Cryogenic SEM shows the gas-hydrate phase forming primarily as a pore-filling material between the sediment grains at approximately 70–75% saturation, and more sporadically as thin veins typically several tens of microns in diameter. Pore throat diameters vary, but commonly range 20–120 microns. Gas chromatography analyses of the hydrate-forming gas show that it is comprised of mainly methane (>99.9%), indicating that the gas hydrate is structure I. Here we report on the distribution and articulation of the gas-hydrate phase within the cores, the grain morphology of the hydrate, the composition of the sediment host, and the composition of the hydrate-forming gas.

Stern, Laura A.; Lorenson, Thomas D.; Pinkston, John C.

2011-01-01

40

Data from stratigraphic test holes drilled at the U.S. Marine Corps Air Station, Cherry Point, North Carolina, 1994-2001, and periodic water levels, 2000-2003  

USGS Publications Warehouse

Nine stratigraphic test holes, from 158 to 305 feet deep, were drilled at the U.S. Marine Corps Air Station at Cherry Point, North Carolina, between 1994 and 2001 by the U.S. Geological Survey. These test holes and subsequent wells provide information about the lithology, stratigraphy, and geology at the Marine Corps Air Station. In addition, ground-water-level data were collected at the Air Station through 2003. The U.S. Geological Survey also conducted high-resolution marine and land seismic surveys during this investigation. The ground-water-level data and locations of the seismic survey lines are included in this report. The stratigraphic data combined with the seismic data provide a basis for the delineation of paleochannels beneath the Air Station as well as information for the management of water resources at the Air Station.

Wrege, Beth M.; Jen, Philip S.

2004-01-01

41

High-resolution well-log derived dielectric properties of gas-hydrate-bearing sediments, Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

USGS Publications Warehouse

A dielectric logging tool, electromagnetic propagation tool (EPT), was deployed in 2007 in the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well (Mount Elbert Well), North Slope, Alaska. The measured dielectric properties in the Mount Elbert well, combined with density log measurements, result in a vertical high-resolution (cm-scale) estimate of gas hydrate saturation. Two hydrate-bearing sand reservoirs about 20 m thick were identified using the EPT log and exhibited gas-hydrate saturation estimates ranging from 45% to 85%. In hydrate-bearing zones where variation of hole size and oil-based mud invasion are minimal, EPT-based gas hydrate saturation estimates on average agree well with lower vertical resolution estimates from the nuclear magnetic resonance logs; however, saturation and porosity estimates based on EPT logs are not reliable in intervals with substantial variations in borehole diameter and oil-based invasion.EPT log interpretation reveals many thin-bedded layers at various depths, both above and below the thick continuous hydrate occurrences, which range from 30-cm to about 1-m thick. Such thin layers are not indicated in other well logs, or from the visual observation of core, with the exception of the image log recorded by the oil-base microimager. We also observe that EPT dielectric measurements can be used to accurately detect fine-scale changes in lithology and pore fluid properties of hydrate-bearing sediments where variation of hole size is minimal. EPT measurements may thus provide high-resolution in-situ hydrate saturation estimates for comparison and calibration with laboratory analysis. ?? 2010 Elsevier Ltd.

Sun, Y.; Goldberg, D.; Collett, T.; Hunter, R.

2011-01-01

42

Examination of core samples from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Effects of retrieval and preservation  

USGS Publications Warehouse

Collecting and preserving undamaged core samples containing gas hydrates from depth is difficult because of the pressure and temperature changes encountered upon retrieval. Hydrate-bearing core samples were collected at the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well in February 2007. Coring was performed while using a custom oil-based drilling mud, and the cores were retrieved by a wireline. The samples were characterized and subsampled at the surface under ambient winter arctic conditions. Samples thought to be hydrate bearing were preserved either by immersion in liquid nitrogen (LN), or by storage under methane pressure at ambient arctic conditions, and later depressurized and immersed in LN. Eleven core samples from hydrate-bearing zones were scanned using x-ray computed tomography to examine core structure and homogeneity. Features observed include radial fractures, spalling-type fractures, and reduced density near the periphery. These features were induced during sample collection, handling, and preservation. Isotopic analysis of the methane from hydrate in an initially LN-preserved core and a pressure-preserved core indicate that secondary hydrate formation occurred throughout the pressurized core, whereas none occurred in the LN-preserved core, however no hydrate was found near the periphery of the LN-preserved core. To replicate some aspects of the preservation methods, natural and laboratory-made saturated porous media samples were frozen in a variety of ways, with radial fractures observed in some LN-frozen sands, and needle-like ice crystals forming in slowly frozen clay-rich sediments. Suggestions for hydrate-bearing core preservation are presented.

Kneafsey, T.J.; Lu, H.; Winters, W.; Boswell, R.; Hunter, R.; Collett, T.S.

2011-01-01

43

Analysis of core samples from the BPXA-DOE-USGS Mount Elbert gas hydrate stratigraphic test well: Insights into core disturbance and handling  

SciTech Connect

Collecting and preserving undamaged core samples containing gas hydrates from depth is difficult because of the pressure and temperature changes encountered upon retrieval. Hydrate-bearing core samples were collected at the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well in February 2007. Coring was performed while using a custom oil-based drilling mud, and the cores were retrieved by a wireline. The samples were characterized and subsampled at the surface under ambient winter arctic conditions. Samples thought to be hydrate bearing were preserved either by immersion in liquid nitrogen (LN), or by storage under methane pressure at ambient arctic conditions, and later depressurized and immersed in LN. Eleven core samples from hydrate-bearing zones were scanned using x-ray computed tomography to examine core structure and homogeneity. Features observed include radial fractures, spalling-type fractures, and reduced density near the periphery. These features were induced during sample collection, handling, and preservation. Isotopic analysis of the methane from hydrate in an initially LN-preserved core and a pressure-preserved core indicate that secondary hydrate formation occurred throughout the pressurized core, whereas none occurred in the LN-preserved core, however no hydrate was found near the periphery of the LN-preserved core. To replicate some aspects of the preservation methods, natural and laboratory-made saturated porous media samples were frozen in a variety of ways, with radial fractures observed in some LN-frozen sands, and needle-like ice crystals forming in slowly frozen clay-rich sediments. Suggestions for hydrate-bearing core preservation are presented.

Kneafsey, Timothy J.; Lu, Hailong; Winters, William; Boswell, Ray; Hunter, Robert; Collett, Timothy S.

2009-09-01

44

Examination of core samples from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Effects of retrieval and preservation  

SciTech Connect

Collecting and preserving undamaged core samples containing gas hydrates from depth is difficult because of the pressure and temperature changes encountered upon retrieval. Hydrate-bearing core samples were collected at the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well in February 2007. Coring was performed while using a custom oil-based drilling mud, and the cores were retrieved by a wireline. The samples were characterized and subsampled at the surface under ambient winter arctic conditions. Samples thought to be hydrate bearing were preserved either by immersion in liquid nitrogen (LN), or by storage under methane pressure at ambient arctic conditions, and later depressurized and immersed in LN. Eleven core samples from hydrate-bearing zones were scanned using x-ray computed tomography to examine core structure and homogeneity. Features observed include radial fractures, spalling-type fractures, and reduced density near the periphery. These features were induced during sample collection, handling, and preservation. Isotopic analysis of the methane from hydrate in an initially LN-preserved core and a pressure-preserved core indicate that secondary hydrate formation occurred throughout the pressurized core, whereas none occurred in the LN-preserved core, however no hydrate was found near the periphery of the LN-preserved core. To replicate some aspects of the preservation methods, natural and laboratory-made saturated porous media samples were frozen in a variety of ways, with radial fractures observed in some LN-frozen sands, and needle-like ice crystals forming in slowly frozen clay-rich sediments. Suggestions for hydrate-bearing core preservation are presented.

Kneafsey, T.J.; Liu, T.J. H.; Winters, W.; Boswell, R.; Hunter, R.; Collett, T.S.

2011-06-01

45

Gas geochemistry of the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: implications for gas hydrate exploration in the Arctic  

USGS Publications Warehouse

Gases were analyzed from well cuttings, core, gas hydrate, and formation tests at the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well, drilled within the Milne Point Unit, Alaska North Slope. The well penetrated a portion of the Eileen gas hydrate deposit, which overlies the more deeply buried Prudhoe Bay, Milne Point, West Sak, and Kuparuk River oil fields. Gas sources in the upper 200 m are predominantly from microbial sources (C1 isotopic compositions ranging from ?86.4 to ?80.6‰). The C1 isotopic composition becomes progressively enriched from 200 m to the top of the gas hydrate-bearing sands at 600 m. The tested gas hydrates occur in two primary intervals, units D and C, between 614.0 m and 664.7 m, containing a total of 29.3 m of gas hydrate-bearing sands. The hydrocarbon gases in cuttings and core samples from 604 to 914 m are composed of methane with very little ethane. The isotopic composition of the methane carbon ranges from ?50.1 to ?43.9‰ with several outliers, generally decreasing with depth. Gas samples collected by the Modular Formation Dynamics Testing (MDT) tool in the hydrate-bearing units were similarly composed mainly of methane, with up to 284 ppm ethane. The methane isotopic composition ranged from ?48.2 to ?48.0‰ in the C sand and from ?48.4 to ?46.6‰ in the D sand. Methane hydrogen isotopic composition ranged from ?238 to ?230‰, with slightly more depleted values in the deeper C sand. These results are consistent with the concept that the Eileen gas hydrates contain a mixture of deep-sourced, microbially biodegraded thermogenic gas, with lesser amounts of thermogenic oil-associated gas, and coal gas. Thermal gases are likely sourced from existing oil and gas accumulations that have migrated up-dip and/or up-fault and formed gas hydrate in response to climate cooling with permafrost formation.

Lorenson, T.D.; Collett, T.S.; Hunter, R.B.

2011-01-01

46

Offshore Technology  

NSDL National Science Digital Library

Offshore Technology is a Web site specifically geared for the offshore oil and gas industry. The highlight of the site is the Industry Projects link, which gives information about offshore drilling projects from around the world. Sites are categorized geographically and include description of the project, information on the geology of the area, drilling history of the site, wellhead platform, pipeline information, and much more. Other links on the main page include an A to Z listing of contractors and suppliers, exhibition and conference information, and other helpful resources for the offshore drilling professional and researcher.

47

Offshore Wind Research (Fact Sheet)  

SciTech Connect

This 2-page fact sheet describes NREL's offshore wind research and development efforts and capabilities. The National Renewable Energy Laboratory is internationally recognized for offshore wind energy research and development (R&D). Its experience and capabilities cover a wide spectrum of wind energy disciplines. NREL's offshore wind R&D efforts focus on critical areas that address the long-term needs of the offshore wind energy industry and the Department of Energy (DOE). R&D efforts include: (1) Developing offshore design tools and methods; (2) Collaborating with international partners; (3) Testing offshore systems and developing standards; (4) Conducting economic analyses; (5) Characterizing offshore wind resources; and (6) Identifying and mitigating offshore wind grid integration challenges and barriers. NREL has developed and maintains a robust, open-source, modular computer-aided engineering (CAE) tool, known as FAST. FAST's state-of-the-art capabilities provide full dynamic system simulation for a range of offshore wind systems. It models the coupled aerodynamic, hydrodynamic, control system, and structural response of offshore wind systems to support the development of innovative wind technologies that are reliable and cost effective. FAST also provides dynamic models of wind turbines on offshore fixed-bottom systems for shallow and transitional depths and floating-platform systems in deep water, thus enabling design innovation and risk reduction and facilitating higher performance designs that will meet DOE's cost of energy, reliability, and deployment objectives.

Not Available

2011-10-01

48

Offshore medicine.  

PubMed

Offshore life can be refreshing for medics who are looking for a little change of pace; however, it is not for everyone. Working offshore can be the easiest or most boring job you'll ever have. It takes a specific type of medic to fit this mold. So, if you are considering a career in the offshore field, take all of the above into consideration. You are not just making a change in jobs, but a change in lifestyle. Once you become accustomed to this lifestyle, it will be hard to go back to the everyday hustle and bustle of the streets. For more information about working offshore, contact Acadian Contract Services at 800/259-333, or visit www.acadian.com. PMID:11258303

Baker, D

2001-03-01

49

Holocene earthquake record offshore Portugal (SW Iberia): testing turbidite paleoseismology in a slow-convergence margin  

NASA Astrophysics Data System (ADS)

The SW margin of the Iberian Peninsula hosts the present-day boundary between the Eurasian and African Plates. Convergence (4-5 mm/yr) is accommodated through a wide deformation zone characterized by moderate magnitude seismic activity. This zone has also been the source of the most important seismic events in Western Europe, such as the 1755 Lisbon Earthquake and Tsunami and 1969 Horseshoe Earthquake. Despite efforts to identify active seismogenic structures in the Gulf of Cadiz in the last ten years, little is known about its paleoseismic history. The turbidite paleoseismology approach was applied for the first time in a low-rate convergent margin to determine the recurrence interval of large earthquake events that occurred in SW Iberia during the Holocene. Four sediment cores collected at strategically located sites offshore Portugal (i.e. Tagus Abyssal Plain, Infante Don Henrique Basin and Horseshoe Abyssal Plain) reveal that these deep-sea basins preserve a record of episodic deposition of turbidites. In the SW Iberian Margin excluding special climatic events, earthquakes are the most likely triggering mechanism for synchronous, widely-spaced distributed turbidites during the Holocene, when the sea level was relatively stable. Age correlation together with textural, mineralogical, physical properties and geochemical signatures of the new cores complemented by pre-existing multicores and gravity cores reveals a total of 7 widespread turbidite events for the Holocene. Precise dating of the most recent turbidite event (E1) based on 210Pb and 137Cs geochronology provides an age of AD 1971 ± 3. This age corresponds to a high-magnitude instrumental earthquake in the region: the 1969 Horseshoe Earthquake (Mw 8.0). Calibrated 14C ages of subsequent widespread turbidite events (E3 and E5) correlate with the dates of important historical earthquakes and paleotsunami deposits in the Gulf of Cadiz area, such as AD 1755 and 218 BC, respectively. If older synchronous events (E6, E8, and E10) with ages ranging from 4960-5510 yr BP to 8715-9015 yr BP are also taken into account, a great earthquake recurrence interval of about 1800 years is obtained for the Holocene. Our correlations suggest that the turbidite record may be considered as a proxy for paleoseismic activity in low-convergence rate margins, and a valuable complementary tool in earthquake and tsunami hazard assessment along the coasts of the Iberian Peninsula and North Africa.

Gràcia, Eulàlia; Vizcaino, Alexis; Escutia, Carlota; Asioli, Alessandra; Rodés, Ángel; Pallàs, Raimon; Garcia-Orellana, Jordi; Lebreiro, Susana; Goldfinger, Chris

2010-05-01

50

The 2011 Japanese 9.0 magnitude earthquake: Test of a kinetic energy wave model using coastal configuration and offshore gradient of Earth and beyond  

NASA Astrophysics Data System (ADS)

Based on geological investigations of coastal geometry and stratigraphy, offshore gradient variation, wave velocity/energy, and quartz grain microtexture analysis of key sites inundated by tsunamis during the Holocene, we have developed a postulated model that could be used to assess modern and ancient onshore environmental conditions during tsunami emplacement. Given that tsunami waves can travel up to ~ 900 km/h, the kinetic energy of the wave is determined by frictional release on the offshore slope to seabed, nearshore sand and sediment supply, and coastal geomorphology, specifically coast linearity or embayments that constrict wave energy. With gentle offshore gradients and relatively linear coastlines, the kinetic energy of the tsunami is decreased by friction with the seabed and radiated outward along the coast, thus producing reduced flooding of the affected coast and fewer collisions of entrained grains. In contrast, steep offshore gradients reduce friction to mere milliseconds of wave impact, and embayments, specifically narrow coastal constrictions, increase wave energy, both of which increase on land run-up heights, and importantly to our proposed model, grain collision effects. Damage to quartz grains deposited by tsunamis along coastal extents ranges from slight on linear coasts with gentle offshore gradients to highly resurfaced mineral surfaces on coasts with steep offshore gradients and narrow embayments. Our model can be further tested through collection, analyses, and comparison of quartz grains in relatively low- and high-energy environments of the recently tsunami-impacted northeastern coast of Japan. For example, the location of the Fukushima nuclear plant along a linear coastline with a less steep offshore gradient may have attenuated the energy of the incoming wave, and thus yielding less resurfaced grains when compared to the coastline located to the north of Sendai City where coastal embayments of variable size coupled with steep offshore gradients would produce higher-energy waves of greater magnitude, as attested by greater penetration inland with considerable loss of life and property damage, and resulting highly deformed grain surfaces. The model could be applicable for assessing modern and ancient coastal environmental conditions on Earth and postulated ancient marine conditions on the Red Planet.

Mahaney, William C.; Dohm, James M.

2011-07-01

51

NaREC Offshore and Drivetrain Test Facility Collaboration: Cooperative Research and Development Final Report, CRADA Number CRD-04-140  

SciTech Connect

The National Renewable Energy Laboratory (NREL) and the National Renewable Energy Centre (NaREC) in the United Kingdom (UK) have a mutual interest in collaborating in the development of full-scale offshore wind energy and drivetrain testing facilities. NREL and NaREC will work together to share resources and experiences in the development of future wind energy test facilities. This Cooperative Research and Development Agreement (CRADA) includes sharing of test protocols, infrastructure cost data, test plans, pro forma contracting instruments, and safe operating strategies. Furthermore, NREL and NaREC will exchange staff for training and development purposes.

Musial, W.

2014-08-01

52

Stratigraphic Architecture of Table Rock, Boise, Idaho  

NSDL National Science Digital Library

In the GEOS 315 â Sedimentology and Stratigraphy course at Boise State University, students conduct field research over a period of 4-5 weeks at Table Rock, a prominent sandstone plateau and popular hiking destination above Boise, ID. Table Rock is composed primarily of nearshore lacustrine sediments deposited along the margins of Mio-Pliocene Lake Idaho. In addition to measuring and correlating stratigraphic sections to describe the facies architecture, students are required to formulate and test an original hypothesis. The primary assessment criteria are field notes, a 4-page research proposal, and a poster presentation summarizing their research results.

Sam Matson

53

Flight test evaluation of a video tracker for enhanced offshore airborne radar approach capability  

NASA Technical Reports Server (NTRS)

As a part of NASA's Rotorcraft All-Weather Operations Research Program, advanced airborne radar approach (ARA) concepts are being investigated. Since data from previous NASA/FAA flight tests showed significant ARA limitations, a research program was initiated at NASA Ames Research Center to determine the benefit that could be derived by automating certain radar functions and superimposing course display data on the radar display. To evaluate these concepts, a newly developed video tracking system which interfaces with weather radar was acquired. After the pilot designates a destination target, the system tracks the target video as it moves on the radar indicator. Using a small, efficient microprocessor, the autotracker presents valuable approach data on the radar screen and automatically adjusts the radar gain and tilt. Results of a limited flight test evaluation of the autotracker show that the course display concept, combined with automated gain and tilt functions, is effective for improving ARA's and reducing radar operator workload.

Clary, G. R.; Cooper, P. G.

1982-01-01

54

The scientific objectives and program of the Japanese offshore methane hydrate production test  

NASA Astrophysics Data System (ADS)

A gas production attempt from deepwater marine methane hydrate deposits is planned in early 2013 in the AT1 site in the north slope Daini-Atsumi Knoll in the Eastern Nankai Trough. The scientific goal of this production test is to understand the behavior of methane hydrate dissociation under an in-situ condition. The program includes one to several weeks of gas flow by applying depressurization technique. Drilling operations for the production test started in February 2012 at the test location, and two monitoring boreholes and part of production well have been drilled and completed. Reservoir characterization study is an essential part of the science program. For this purpose, intensive geophysical logging and coring programs are included in the drilling program. The logging data were mainly obtained from a hole named AT1-MC. The well was drilled with LWD tools, wireline logging suits were run subsequently. Also pressure-preserved cores were recovered from methane hydrate-concentrated and overburden sections in a dedicated borehole (AT1-C). To keep the pressure and temperature of cores under gas hydrate stability condition all the time, pressure core analysis and transfer system (PCATS) was used. Also the PCATS-triaxial device that can make mechanical and physical property measurements possible under tri-axial effective stress conditions was utilized. The physical, hydraulic and mechanical properties obtained from core and log data will be used for modeling works, and given to the numerical simulator MH21-HYDRES for methane hydrate production modeling as input parameters for forward analysis and inversion (history matching) to understand the in-situ processes. The monitoring of the methane hydrate dissociation processes is another important subject. The two monitoring holes have temperature sensors to detect temperature drop and recovery due to gas hydrate dissociation and heat transfer. Also, one of the monitoring holes is kept re-accessible to allow cased-hole geophysical logging before and after the production test. A geophone array in an ocean bottom cable (OBC) will be deployed for a multi-component and time-lapse seismic survey on the seafloor. During the flow test, water and gas production rates, downhole temperature and pressure will be monitored. Comparison between actual well response and computed value from the numerical model will correct and improve our knowledge about reservoir characters and forecast of long-term productivity. JOGMEC, AIST and related scientists and engineers analyze the data to make unseen underground processes visible.;

Yamamoto, K.; Fujii, T.; Noguchi, S.; Nagao, J.

2012-12-01

55

Aerodynamic Thrust Modelling in Wave Tank Tests of Offshore Floating Wind Turbines Using a Ducted Fan  

NASA Astrophysics Data System (ADS)

Wave tank testing of scaled models is standard practice during the development of floating wind turbine platforms for the validation of the dynamics of conceptual designs. Reliable recreation of the dynamics of a full scale floating wind turbine by a scaled model in a basin requires the precise scaling of the masses and inertias and also the relevant forces and its frequencies acting on the system. The scaling of floating wind turbines based on the Froude number is customary for basin experiments. This method preserves the hydrodynamic similitude, but the resulting Reynolds number is much lower than in full scale. The aerodynamic loads on the rotor are therefore out of scale. Several approaches have been taken to deal with this issue, like using a tuned drag disk or redesigning the scaled rotor. This paper describes the implementation of an alternative method based on the use of a ducted fan located at the model tower top in the place of the rotor. The fan can introduce a variable force that represents the total wind thrust by the rotor. A system controls this force by varying the rpm, and a computer simulation of the full scale rotor provides the desired thrust to be introduced by the fan. This simulation considers the wind turbine control, gusts, turbulent wind, etc. The simulation is performed in synchronicity with the test and it is fed in real time by the displacements and velocities of the platform captured by the acquisition system. Thus, the simulation considers the displacements of the rotor within the wind field and the calculated thrust models the effect of the aerodynamic damping. The system is not able currently to match the effect of gyroscopic momentum. The method has been applied during a test campaign of a semisubmersible platform with full catenary mooring lines for a 6MW wind turbine in scale 1/40 at Ecole Centrale de Nantes. Several tests including pitch free decay under constant wind and combined wave and wind cases have been performed. Data from the experiments are compared with aero-servo-hydro-elastic computations with good agreement showing the validity of the method for the representation of the scaled aerodynamics. The new method for the aerodynamic thrust scaling in basin tests is very promising considering its performance, versatility and lower cost in comparison with other methods.

Azcona, José; Bouchotrouch, Faisal; González, Marta; Garciandía, Joseba; Munduate, Xabier; Kelberlau, Felix; Nygaard, Tor A.

2014-06-01

56

Testing 8000 years of submarine paleoseismicity record offshore western Algeria : First evidence for irregular seismic cycles  

NASA Astrophysics Data System (ADS)

It is commonly assumed that stress buildup along a given fault is proportional to the time elapsed since the previous earthquake. Although the resulting « seismic gap » hypothesis suits well for moderate magnitude earthquakes (Mw 4-5), large events (Mw>6) are hardly predictable and depict great variation in recurrence intervals. Models based on stress transfer and interactions between faults argue that an earthquake may promote or delay the occurrence of next earthquakes on adjacent faults by increasing or lowering the level of static stress. The Algerian margin is a Cenozoic passive margin presently inverted within the slow convergence between Africa and Eurasia plates (~3-6 mm/yr). The western margin experienced two large earthquakes in 1954 (Orléansville, M 6.7) and 1980 (El Asnam, M 7.3), supporting an interaction between the two faults. To get meaningful statistics of large earthquakes recurrence intervals over numerous seismic cycles, we conducted a submarine paleoseismicity investigation based on turbidite chronostratigraphy. As evidenced on the Cascadia subduction zone, synchronous turbidites accumulated over a large area and originated from independent sources are likely triggered by an earthquake. To test the method on a slowly convergent margin, we analyze turbidites from three sediment cores collected during the Maradja (2003) and Prisme (2007) cruises off the 1954-1980 source areas. We use X-ray radioscopy, XRF major elements counter, magnetic susceptibility, and grain-size distribution to accurately discriminate turbidites from hemipelagites. We date turbidites by calculating hemipelagic sedimentation rates obtained with radiocarbon ages, and interpolate the rates between turbidites. Finally, the age of events is compared with the only paleoseismic study available on land (El Asnam fault). Fourteen possible seismic events are identified by the counting and correlation of turbidites over the last 8 ka. Most events are correlated with the paleoseismic record of the El Asnam fault, but uncorrelated events suggest that other faults were active. Only the 1954 event (not the 1980) triggered a turbidity current, implying that the sediment buffer on the continental shelf could not be reloaded in 26 years, thus arguing for a minimum time resolution of our method. The new paleoseismic catalog shows a recurrence interval of 300-700 years for most events, but also a great interval of >1200 years without any major earthquake. This result suggests that the level of static stress may have drastically dropped as a result of three main events occurring within the 800 years prior the quiescence period.

Ratzov, G.; Cattaneo, A.; Babonneau, N.; Yelles, K.; Bracene, R.; Deverchere, J.

2012-12-01

57

A Risk Analysis Methodology to Address Human and Organizational Factors in Offshore Drilling Safety: With an Emphasis on Negative Pressure Test  

NASA Astrophysics Data System (ADS)

According to the final Presidential National Commission report on the BP Deepwater Horizon (DWH) blowout, there is need to "integrate more sophisticated risk assessment and risk management practices" in the oil industry. Reviewing the literature of the offshore drilling industry indicates that most of the developed risk analysis methodologies do not fully and more importantly, systematically address the contribution of Human and Organizational Factors (HOFs) in accident causation. This is while results of a comprehensive study, from 1988 to 2005, of more than 600 well-documented major failures in offshore structures show that approximately 80% of those failures were due to HOFs. In addition, lack of safety culture, as an issue related to HOFs, have been identified as a common contributing cause of many accidents in this industry. This dissertation introduces an integrated risk analysis methodology to systematically assess the critical role of human and organizational factors in offshore drilling safety. The proposed methodology in this research focuses on a specific procedure called Negative Pressure Test (NPT), as the primary method to ascertain well integrity during offshore drilling, and analyzes the contributing causes of misinterpreting such a critical test. In addition, the case study of the BP Deepwater Horizon accident and their conducted NPT is discussed. The risk analysis methodology in this dissertation consists of three different approaches and their integration constitutes the big picture of my whole methodology. The first approach is the comparative analysis of a "standard" NPT, which is proposed by the author, with the test conducted by the DWH crew. This analysis contributes to identifying the involved discrepancies between the two test procedures. The second approach is a conceptual risk assessment framework to analyze the causal factors of the identified mismatches in the previous step, as the main contributors of negative pressure test misinterpretation. Finally, a rational decision making model is introduced to quantify a section of the developed conceptual framework in the previous step and analyze the impact of different decision making biases on negative pressure test results. Along with the corroborating findings of previous studies, the analysis of the developed conceptual framework in this paper indicates that organizational factors are root causes of accumulated errors and questionable decisions made by personnel or management. Further analysis of this framework identifies procedural issues, economic pressure, and personnel management issues as the organizational factors with the highest influence on misinterpreting a negative pressure test. It is noteworthy that the captured organizational factors in the introduced conceptual framework are not only specific to the scope of the NPT. Most of these organizational factors have been identified as not only the common contributing causes of other offshore drilling accidents but also accidents in other oil and gas related operations as well as high-risk operations in other industries. In addition, the proposed rational decision making model in this research introduces a quantitative structure for analysis of the results of a conducted NPT. This model provides a structure and some parametric derived formulas to determine a cut-off point value, which assists personnel in accepting or rejecting an implemented negative pressure test. Moreover, it enables analysts to assess different decision making biases involved in the process of interpreting a conducted negative pressure test as well as the root organizational factors of those biases. In general, although the proposed integrated research methodology in this dissertation is developed for the risk assessment of human and organizational factors contributions in negative pressure test misinterpretation, it can be generalized and be potentially useful for other well control situations, both offshore and onshore; e.g. fracking. In addition, this methodology can be applied for the analysis

Tabibzadeh, Maryam

58

Measures of stratigraphic fit to phylogeny and their sensitivity to tree size, tree shape, and scale  

Microsoft Academic Search

Measures of stratigraphic fit to phylogeny are analyzed to test how they are affected by the shape and size of the phylogenetic trees and by the number of stratigraphic intervals encompassed. Monte Carlo randomizations are used to investigate the sensitivity of three commonly used measures (SCI, GER and MSM*) approximating their distribution of possible values under certain conditions. All are

Diego Pol; Mark A. Norell; Mark E. Siddall

2004-01-01

59

X-ray CT Observations of Methane Hydrate Distribution Changes over Time in a Natural Sediment Core from the BPX-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well  

SciTech Connect

When maintained under hydrate-stable conditions, methane hydrate in laboratory samples is often considered a stable and immobile solid material. Currently, there do not appear to be any studies in which the long-term redistribution of hydrates in sediments has been investigated in the laboratory. These observations are important because if the location of hydrate in a sample were to change over time (e.g. by dissociating at one location and reforming at another), the properties of the sample that depend on hydrate saturation and pore space occupancy would also change. Observations of hydrate redistribution under stable conditions are also important in understanding natural hydrate deposits, as these may also change over time. The processes by which solid hydrate can move include dissociation, hydrate-former and water migration in the gas and liquid phases, and hydrate formation. Chemical potential gradients induced by temperature, pressure, and pore water or host sediment chemistry can drive these processes. A series of tests were performed on a formerly natural methane-hydrate-bearing core sample from the BPX-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well, in order to observe hydrate formation and morphology within this natural sediment, and changes over time using X-ray computed tomography (CT). Long-term observations (over several weeks) of methane hydrate in natural sediments were made to investigate spatial changes in hydrate saturation in the core. During the test sequence, mild buffered thermal and pressure oscillations occurred within the sample in response to laboratory temperature changes. These oscillations were small in magnitude, and conditions were maintained well within the hydrate stability zone.

Kneafsey, T.J.; Rees, E.V.L.

2010-03-01

60

In-situ gas hydrate hydrate saturation estimated from various well logs at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

USGS Publications Warehouse

In 2006, the U.S. Geological Survey (USGS) completed detailed analysis and interpretation of available 2-D and 3-D seismic data and proposed a viable method for identifying sub-permafrost gas hydrate prospects within the gas hydrate stability zone in the Milne Point area of northern Alaska. To validate the predictions of the USGS and to acquire critical reservoir data needed to develop a long-term production testing program, a well was drilled at the Mount Elbert prospect in February, 2007. Numerous well log data and cores were acquired to estimate in-situ gas hydrate saturations and reservoir properties.Gas hydrate saturations were estimated from various well logs such as nuclear magnetic resonance (NMR), P- and S-wave velocity, and electrical resistivity logs along with pore-water salinity. Gas hydrate saturations from the NMR log agree well with those estimated from P- and S-wave velocity data. Because of the low salinity of the connate water and the low formation temperature, the resistivity of connate water is comparable to that of shale. Therefore, the effect of clay should be accounted for to accurately estimate gas hydrate saturations from the resistivity data. Two highly gas hydrate-saturated intervals are identified - an upper ???43 ft zone with an average gas hydrate saturation of 54% and a lower ???53 ft zone with an average gas hydrate saturation of 50%; both zones reach a maximum of about 75% saturation. ?? 2009.

Lee, M.W.; Collett, T.S.

2011-01-01

61

Design, manufacturing and tests of first cryogen-free MgB2 prototype coils for offshore wind generators  

NASA Astrophysics Data System (ADS)

Although renewable sector has started to take advantage of the offshore wind energy recently, the development is very intense. Turbines reliability, size, and cost are key aspects for the wind industry, especially in marine locations. A superconducting generator will allow a significant reduction in terms of weight and size, but cost and reliability are two aspects to deal with. MgB2 wire is presented as one promising option to be used in superconducting coils for wind generators. This work shows the experimental results in first cryogen-free MgB2 prototype coils, designed according to specific requirements of TECNALIA's wind generator concept.

Sarmiento, G.; Sanz, S.; Pujana, A.; Merino, J. M.; Iturbe, R.; Apiñaniz, S.; Nardelli, D.; Marino, I.

2014-05-01

62

Singularity analysis: a tool for extracting lithologic and stratigraphic content from seismic data  

E-print Network

In this work, we test an amplitude-independent method of seisimic data analysis designed to extract lithologic information about stratigraphic horizons. We apply the method of singularity characterization in an attempt to ...

Lyons, William J.

2001-01-01

63

Drilling tools for continuous offshore operations  

SciTech Connect

Offshore drilling tools are still the object of improvement aimed in achieving maximum production or scientific effect of minimum costs. One of perspective ways of improving offshore scientific drilling indices is utilization of drilling systems which provide continuous hole penetration without pulling out the drill string aboard of drill vessel for bit replacement. The report presents specific features of the drilling tools supplying Complete Coring System (CCS) operations. CCS can provide continuous coring and drilling as well as logging in any geological profiles from the soft to very hard formations. One of the basic principles in coring is slimhole pilot drilling, thus giving many advantages. Development of drilling tools for CCS is based upon vast experience in designing drilling tools, including the retractable bits. In perspective CCS can be applied in stratigraphic and scientific drilling in deep water, especially in complicated geological conditions.

Gelfgat, M.Y. [Aquatic Company, Ltd., Moscow (Russian Federation); Surkov, D.V.; Buyanovsky, I.N. [All-Russia Scientific Research Inst. of Drilling Techniques, Moscow (Russian Federation)

1995-12-31

64

Application of TIMS data in stratigraphic analysis  

NASA Technical Reports Server (NTRS)

An in-progress study demonstrates the utility of Thermal Infrared Multispectral Scanner (TIMS) data for unraveling the stratigraphic sequence of a western interior, North American foreland basin. The TIMS data can be used to determine the stratigraphic distribution of minerals that are diagnostic of specific depositional distribution. The thematic mapper (TM) and TIMS data were acquired in the Wind River/Bighorn area of central Wyoming in November 1982, and July 1983, respectively. Combined image processing, photogeologic, and spectral analysis methods were used to: map strata; construct stratigraphic columns; correlate data; and identify mineralogical facies.

Lang, H. R.

1986-01-01

65

Underbalanced drilling benefits now available offshore  

SciTech Connect

Offshore underbalanced drilling (UBD) is a reality. Applications in older, partially depleted fields and new fields are being considered. However, low productivity reservoirs and fields with sub normal pressures causing drilling problems are currently the main targets for offshore UBD. With proper planning and the correct technique, both jointed pipe and coiled tubing UBD drilling operations have been carried out offshore with success. The main concerns for offshore UBD have been altered drilling practices and surface production system operation. These issues have been examined and equipment has been designed and tested to address them. Environmental, safety and health issues are paramount and have been studied carefully. Detailed well planning, engineering, and flow modeling have proven critical for successful offshore UBD operations. Examples are given from oil and gas fields.

Vozniak, J.P.; Cuthbertson, B.; Nessa, D.O.

1997-05-01

66

Application of sequence stratigraphy to oil and gas exploration in Bredasdorp basin offshore South Africa  

Microsoft Academic Search

For more than two decades, oil and gas exploration in offshore South African rift basins within structural synrift plays yielded limited success. After the first oil discovery in postrift sediments in the Bredasdorp basin in 1987, sequence-stratigraphic concepts were applied to the Lower Cretaceous postrift sequences to permit correlation of depositional systems tracts and related facies throughout the basin. Extensive

Van Wyk

1989-01-01

67

Some debatable problems of stratigraphic classification  

NASA Astrophysics Data System (ADS)

Russian geologists perform large-scale geological mapping in Russia and abroad. Therefore we urge unification of legends of geological maps compiled in different countries. It seems important to continuously organize discussions on problems of stratigraphic classification. 1. The stratigraphic schools (conventionally called "European" and "American") define "stratigraphy" in different ways. The former prefers "single" stratigraphy that uses data proved by many methods. The latter divides stratigraphy into several independent stratigraphers (litho-, bio-, magneto- and others). Russian geologists classify stratigraphic units into general (chronostratigraphic) and special (in accordance with a method applied). 2. There exist different interpretations of chronostratigraphy. Some stratigraphers suppose that a chronostratigraphic unit corresponds to rock strata formed during a certain time interval (it is somewhat formalistic because a length of interval is frequently unspecified). Russian specialists emphasize the historical-geological background of chronostratigraphic units. Every stratigraphic unit (global and regional) reflects a stage of geological evolution of biosphere and stratisphere. 3. In the view of Russian stratigraphers, the main stratigraphic units may have different extent: a) global (stage), b) regional (regional stage,local zone), and c) local (suite). There is no such hierarchy in the ISG. 4. Russian specialists think that local "lithostratigraphic" units (formations) which may have diachronous boundaries are not chronostratigraphic ones in strict sense (actually they are lithological bodies). In this case "lithostratigraphy" can be considered as "prostratigraphy" and employed in initial studies of sequences. Therefore, a suite is a main local unit of the Russian Code and differs from a formation, although it is somewhat similar. It does not mean that lithostratigraphy is unnecessary. Usage of marker horizons, members and other bodies is of great help. Lithostratigraphy may be regarded as the start of geological mapping on scales of 1 : 10 000, 1 : 25 000 or 1 : 50 000, and lithostratigraphic subdivisions can be used as the mapping units because they practically have isochronic boundaries when we deal with geological mapping on these scales. 5. Russian geologists interpret a chronozone (defined with due account of the standard assemblage-zone) as a part of a stage. In opinion of other specialists, zones serve as correction markers. This gives rise to controversy where zonal scales are needed for the Phanerozoic or whether stage scales are sufficient. In the Russian Code a chronozone is referred to general stratigraphic units (less than a stage). 6. The popular GSSP "concept" may be is inadequate in the broad sense because stages remain "empty" and do not reflect geological events. The search of "golden spikes" can be useful as a part of comprehensive investigations of stratigraphic subdivisions. "Silver" and other type spike-markers can be used as well as recommended by event stratigraphy (Ager, 1973). 7. A new version of "International Stratigraphic Guide" should include not only recommendations but also alternative views. However the work must not be done in a hurry! In avoid bias representatives of interested countries should be involved. Finally, I would like to make two proposals. Proposal 1. A special symposium should be held during the second International Congress on Stratigraphy-2015 to review national stratigraphic codes (USA, Germany, Great Britain, China, Russia, Australia and other countries). This can provide better understanding of their similarities and dissimilarities and enable to realize how much they differ from each other. The review may show the present state of the stratigraphic classification and reveal both pressing and alleged problems of stratigraphy of the early XXI century. Proposal 2. It would be appropriate to prepare a special publication presenting briefly c

Gladenkov, Yury

2014-05-01

68

Sedimentary sequence of offshore southeastern US: preliminary study based on exploration wells  

SciTech Connect

In 1982, geologic data from the exploratory wells in the offshore southeastern US were released to the public. Prior to this time, well data were limited the the COST (Continental Offshore Stratigraphic Test) GE-1 well, the first deep-penetration well, which was completed in 1977. Six additional exploration wells were completed thereafter. Although these wells were dry holes, information provided by them has contributed to the geologic interpretation of the Atlantic margin. The oldest rocks penetrated by these wells are Paleozoic indurated shale and argillite, sandstone and weakly metamorphosed quartzite, and igneous rocks. The post-Paleozoic section ranges from 2220 to 3660 m (7280 to 12,000 ft) thick at the well sites, but seismic data indicate that equivalent section thickens to 10-12 km (6-7 mi) beneath the Blake plateau. The Lower Cretaceous through Cenozoic section represents a progression from nonmarine and marginal marine to marine sedimentation. Three main units are recognized: lower siliciclastic, middle calcareous mudstone, and upper limestone. The siliciclastic unit consists of interbedded gray to red-brown sandstone, siltstone, and shale with some conglomerate, coal, evaporites, and carbonate rocks. Based on petrographic examination, the sandstone compositions, vary between arkose, litharenite, and quartz arenite. Calcareous clay and shale (grading to shaly limestone) overlie the siliciclastic rocks. The upper limestone contains chert, oolites, and shell fragments and ranges in composition from micrite to sparite. By comparing these units to the onshore Georgia sedimentary section, regional lithofacies trends that can be useful for future exploration are recognized.

Libby-French, J.

1984-04-01

69

Stratigraphic Columns Across Southern Western Interior  

NSDL National Science Digital Library

This website depicts stratigraphic columns of exposed rocks in southwestern regions of the United States. A general explanation of symbols used in the columns is provided for reference, and the columns indicate rock type, formation names and geologic time periods. The areas covered include the Grand Canyon, central and southern Arizona, southern Utah and Nevada, and western New Mexico and Colorado.

Ronald Blakey

70

Offshore Wind Turbines - Estimated Noise from Offshore Wind Turbine, Monhegan Island, Maine: Environmental Effects of Offshore Wind Energy Development  

Microsoft Academic Search

Deep C Wind, a consortium headed by the University of Maine will test the first U.S. offshore wind platforms in 2012. In advance of final siting and permitting of the test turbines off Monhegan Island, residents of the island off Maine require reassurance that the noise levels from the test turbines will not disturb them. Pacific Northwest National Laboratory, at

Pamela M. Aker; Anthony M. Jones; Andrea E. Copping

2010-01-01

71

Drilling and data acquisition programs for the methane hydrate offshore production test in the Eastern Nankai Trough  

NASA Astrophysics Data System (ADS)

Marine methane hydrates are a matter of scientific interests from various viewpoints such as a key player of global carbon cycle, effects on climate change, cause of seafloor instability, and a possible future energy resource. Under the Japanese national research program, the MH21 research consortium (Japan Oil, Gas and Metals National Corporation and National Institute of Advanced Industrial Science and Technology) has conducted survey operations and subsequent analyses of data and samples from methane hydrate-bearing sediments in the Eastern Nankai Trough. The goal of the project was a gas production test from a methane hydrate deposits in sandy intervals of Pleistocene turbidite sediments. The test location was set in Daini Atsumi Knoll that is a ridge between forearc basin and accretionary prism, and the sediments cover the flank of the knoll. The water depth at the test location is approximately 1000m, and 50m thick methane hydrate concentrated zone exists around 300m below seafloor. The main interest of the MH21 research team is to know physical (thermal, hydraulic, and mechanical) parameters of sediments that are necessary to understand gas hydrate dissociation processes during the production test. Core samples and geophysical logging data obtained during past surveys are utilized for this purpose. Sedimentation and tectono-geophysical conditions govern such material properties, so the samples were analyzed from those viewpoints, too. The first drilling at the location was done in 2004 with logging and coring operation including pressure-conserved core sampling. In 2011, shallow geotechnical survey holes were drilled in the area for geo-hazard assessment, and core samples were taken in the holes, along with some in-situ mechanical and hydraulic testings. In early 2012, a well construction operation for the gas production test was conducted with logging operations that contains neutron porosity data using pulse-neutron devices, magnetic resonance log, etc. A core sampling operation followed in the middle of 2012 using an improved pressure-coring tool and analysis devices. In the March of 2013, the gas production attempt was started using 'depressurization method,' in which liquid in the wellbore was removed by downhole pump to drawdown pore pressure in the formation. The test was accomplished with six day methane gas production. Gas flow rate from the single borehole by depressurization procedure (original 13.5MPa to 4.5MPa at the bottom of the borehole) could provid 20,000Sm3/day gas before the test was forced to terminate due to a sand production problem. An intensive monitoring program accompanied with the test, including two monitoring borehole for time-lapse cased-hole logging and temperature measurements. Moreover, multi-component and time-lapse seismic survey was done using an ocean bottom cable. The taken flow rate, pressure and temperature data, and gas, liquid and solid samples are under detailed analyses to understand the response of methane hydrates in the sediments against depressurization operation, and may provide knowledge of hydrogeology and thermodynamics information of the methane hydrate bearing strata. Some detailed study results are presented in this session and posters.

Yamamoto, K.; Fujii, T.

2013-12-01

72

Offshore oil: an overview  

SciTech Connect

This report provides an assessment of the current status of offshore activity with particular reference to (1) trends in offshore production, and (2) the intensity and location of exploration drilling, this being an essential precondition for any future increase in offshore crude production. The report includes in-depth profiles of those non-OPEC nationa where the chances of discovering further recoverable offshore reserves appear highest. The underlying concern is to identify those nations that are on the offshore frontier. It is these nations that must resolve in an appropriate and timely manner the particular policy issues that arise in the course of offshore oil exploration and production. These issues include (1) the development of appropriate, risk-free offshore technologies, and (2) balancing of conflicting and competing demands for land (recreational use, wetland preservation, siting of infrastructure and energy-related facilities) in the coastal zone. In these respects, the exploitation of offshore oil and gas poses a unique form of challenge.

Manners, I.R.

1980-06-01

73

Stratigraphic turnover on west Africa margin page 1 Early Oligocene stratigraphic turnover on west Africa continental margin: a signature of  

E-print Network

Stratigraphic turnover on west Africa margin page 1 Early Oligocene stratigraphic turnover on west and evolution of the west African margin: The continental margin of west Africa resulted from the Neocomian profiles across #12;Stratigraphic turnover on west Africa margin page 2 the west African continental margin

Demouchy, Sylvie

74

Subsurface sequence stratigraphic correlation using well logs  

NSDL National Science Digital Library

Students are given hard copies of a subsurface section containing gamma and resistivity logs of nine closely-spaced (well distance varies from 1 to 3 km) wells from Delaware Basin, southeast New Mexico for an interval of ~ 200 m clastic succession of Morrow sandstone of Pennsylvanian age. Core sedimentology of one of these wells is also provided. Students' task is to correlate the well logs to generate a stratigraphic cross-section of the area using sequence stratigraphic approach. As the data are from Delaware Basin, southeast New Mexico, student should first gather the knowledge of regional setting of the basin, with a particular emphasis to the paleo-eustasy. (Clue: in Delaware Basin, Morrow sandstones deposited in a low accommodation settings with high-amplitude fluctuations of sea-level.) When correlating the well logs students should start with the well which has lithological information. Students should try to correlate the mudstones first. The two most prominent sequence stratigraphic surfaces with comparatively higher correlation-length are 'sequence boundary' produced by pronounced fall of sea-level, and 'maximum flooding surface' generated at the time of highest stand of sea-level. Students should pay particular attention to incised-valley-fill deposits. After completing the correlation, students should check whether their correlation satisfy our prevailing ideas of sequence stratigraphy and stratal packaging. Student should prepare a brief description of overall depositional environments and sea-level history of the area substantiating their subsurface correlation. By doing this exercise, students will learn how to apply sequence stratigraphic principles in interpreting subsurface data, particularly from well logs.

M. Royhan Gani

75

A nearshore–offshore trend in acritarch distribution from the Early–Middle Ordovician of the Yangtze Platform, South China  

Microsoft Academic Search

The stratigraphical interval of the late Early Ordovician Didymograptus deflexus and the early Middle Ordovician Azygograptus suecicus graptolite Biozones was investigated from seven sections from the upper Yangtze Platform, southern China. These are located on different parts of the platform, between the nearshore environments of the Kunming area, Yunnan Province, and the offshore carbonate shelf of the Yichang area, Hubei

Jun Li; Thomas Servais; Kui Yan; Huaicheng Zhu

2004-01-01

76

The 2011 Japanese 9.0 magnitude earthquake: Test of a kinetic energy wave model using coastal configuration and offshore gradient of Earth and beyond  

Microsoft Academic Search

Based on geological investigations of coastal geometry and stratigraphy, offshore gradient variation, wave velocity\\/energy, and quartz grain microtexture analysis of key sites inundated by tsunamis during the Holocene, we have developed a postulated model that could be used to assess modern and ancient onshore environmental conditions during tsunami emplacement. Given that tsunami waves can travel up to ~ 900 km\\/h,

William C. Mahaney; James M. Dohm

2011-01-01

77

Methane hydrate pore saturation evaluation from geophysical logging and pressure core analysis, at the first offshore production test site in the eastern Nankai Trough, Japan  

NASA Astrophysics Data System (ADS)

On March 2013, the first offshore production test form methane hydrate (MH) concentrated zone (MHCZ) was conducted by the Research Consortium for Methane Hydrate Resource Development in Japan (MH21) at the AT1 site located in the north-western slope of Daini-Atsumi Knoll in the eastern Nankai Trough, Japan. Before the production test, extensive geophysical logging and pressure coring using Hybrid Pressure Coring System were conducted in 2012 at monitoring well (AT1-MC) and coring well (AT1-C), in order to obtain basic information for the MH reservoir characterization. MH pore saturation (Sh) is one of the important basic parameters not only for reservoir characterization, but also the resource assessment. However, precise evaluation of Sh from geophysical logging is still challenging technical issue. The MHCZ confirmed by the geophysical logging at AT1-MC has a turbidite assemblage (from several tens of centimeters to a few meters) with 60 m of gross thickness; it is composed of lobe/sheet type sequences in the upper part, and relatively thick channel sand sequences in the lower part. In this study, the Sh evaluated from geophysical logging data were compared with those evaluated from pressure core analysis. Resistivity logs and nuclear magnetic resonance (NMR) log were used for the Sh evaluation by geophysical logging. Standard Archie equation was applied for Sh evaluation from resistivity log, while density magnetic resonance (DMR) method was used for Sh evaluation from NMR log. The Sh from pressure core samples were evaluated using the amount of dissociated gas volume, together with core sample bulk volume, measured porosity, net sand intervals, and assumed methane solubility in pore water. In the upper part of the MHCZ, Sh estimated from resistivity log showed distinct difference in value between sand and mud layers, compared to Sh from NMR log. Resistivity log has higher vertical resolution than NMR log, so it is favorable for these kinds of thin bed evaluation. In this part, 50 to 80% of Sh was observed in sandy layer, which showed fairly good agreement with core derived Sh. On the other hand, lower part of the MHCZ, Sh estimated from both resistivity and NMR log showed higher background value and relatively smoother curve than upper part. In this part, 50 to 80% of Sh was observed in sandy layer, which was also showed good agreement with core derived Sh. This study was conducted by the Research Consortium for Methane Hydrate Resource Development in Japan (MH21).

Fujii, T.; Suzuki, K.; Takayama, T.; Konno, Y.; Yoneda, J.; Egawa, K.; Ito, T.; Nagao, J.

2013-12-01

78

Session: Offshore wind  

SciTech Connect

This session at the Wind Energy and Birds/Bats workshop consisted of two presentations. Due to time constraints, a discussion period was not possible. The session addressed the current state of offshore wind energy development. The first presentation ''Monitoring Program and Results: Horns Rev and Nysted'' by Jette Gaarde summarized selected environmental studies conducted to date at operating offshore wind turbine projects in Denmark and lessons from other offshore wind developments in Europe. Wildlife impacts studies from the Danish sites focused on birds, fish, and mammals. The second presentation ''What has the U.S. Wind Industry Learned from the European Example'' by Bonnie Ram provided an update on current permit applications for offshore wind developments in the U.S. as well as lessons that may be drawn from the European experience.

Gaarde, Jette; Ram, Bonnie

2004-09-01

79

3D Stratigraphic Modeling of Central Aachen  

NASA Astrophysics Data System (ADS)

Since 1980s, advanced computer hardware and software technologies, as well as multidisciplinary research have provided possibilities to develop advanced three dimensional (3D) simulation software for geosciences application. Some countries, such as USA1) and Canada2) 3), have built up regional 3D geological models based on archival geological data. Such models have played huge roles in engineering geology2), hydrogeology2) 3), geothermal industry1) and so on. In cooperating with the Municipality of Aachen, the Department of Engineering Geology of RWTH Aachen University have built up a computer-based 3D stratigraphic model of 50 meter' depth for the center of Aachen, which is a 5 km by 7 km geologically complex area. The uncorrelated data from multi-resources, discontinuous nature and unconformable connection of the units are main challenges for geological modeling in this area. The reliability of 3D geological models largely depends on the quality and quantity of data. Existing 1D and 2D geological data were collected, including 1) approximately 6970 borehole data of different depth compiled in Microsoft Access database and MapInfo database; 2) a Digital Elevation Model (DEM); 3) geological cross sections; and 4) stratigraphic maps in 1m, 2m and 5m depth. Since acquired data are of variable origins, they were managed step by step. The main processes are described below: 1) Typing errors of borehole data were identified and the corrected data were exported to Variowin2.2 to distinguish duplicate points; 2) The surface elevation of borehole data was compared to the DEM, and differences larger than 3m were eliminated. Moreover, where elevation data missed, it was read from the DEM; 3) Considerable data were collected from municipal constructions, such as residential buildings, factories, and roads. Therefore, many boreholes are spatially clustered, and only one or two representative points were picked out in such areas; After above procedures, 5839 boreholes with -x, -y, -z coordinates, down-hole depth, and stratigraphic information are available. 4) We grouped stratigraphic units into four main layers based on analysis of geological settings of the modeling area. The stratigraphic units extend from Quaternary, Cretaceous, Carboniferous to Devonian. In order to facilitate the determination of each unit boundaries, a series of standard code was used to integrate data with different descriptive attributes. 5) The Quaternary and Cretaceous units are characterized by subhorizontal layers. Kriging interpolation was processed to the borehole data in order to estimate data distribution and surface relief for the layers. 6) The Carboniferous and Devonian units are folded. The lack of software support, concerning simulating folds and the shallow depth of boreholes and cross sections constrained the determination of geological boundaries. A strategy of digitalizing the fold surfaces from cross sections and establishing them as inclined strata was followed. The modeling was simply subdivided into two steps. The first step consisted of importing data into the modeling software. The second step involved the construction of subhorizontal layers and folds, which were constrained by geological maps, cross sections and outcrops. The construction of the 3D stratigraphic model is of high relevance to further simulation and application, such as 1) lithological modeling; 2) answering simple questions such as "At which unit is the water table?" and calculating volume of groundwater storage during assessment of aquifer vulnerability to contamination; and 3) assigned by geotechnical properties in grids and providing them for user required application. Acknowledgements: Borehole data is kindly provided by the Municipality of Aachen. References: 1. Janet T. Watt, Jonathan M.G. Glen, David A. John and David A. Ponce (2007) Three-dimensional geologic model of the northern Nevada rift and the Beowawe geothermal system, north-central Nevada. Geosphere, v. 3; no. 6; p. 667-682 2. Martin Ross, Michel Parent and René Lefebvre (2005) 3D geologic

Dong, M.; Neukum, C.; Azzam, R.; Hu, H.

2010-05-01

80

Photoresponses of larval Atlantic menhaden ( Brevoortia tyrannus Latrobe) in offshore and estuarine waters: implications for transport  

Microsoft Academic Search

This study tested the hypothesis that Atlantic menhaden (Brevoortia tyrannus Latrobe) larvae have separate behaviors in offshore and estuarine waters that are evoked by chemical cues in these waters. Atlantic menhaden spawn offshore, and larvae are transported shoreward where they metamorphose after entering estuaries. Field studies suggest that during the day larvae are at moderate depths offshore and less abundant

Richard B. Forward; John S. Burke; Daniel Rittschof; James M. Welch

1996-01-01

81

A Matter of Coherence: The Effects of Offshoring of Intangibles on Firm Performance  

Microsoft Academic Search

Offshoring of intangibles is a global production strategy based on the decision to externalize intangible activities to foreign countries. In the present work we test the existence of a positive relationship between offshoring intangibles and firm performance. To reap the full benefit of offshoring, firms are required to integrate and coordinate activities and knowledge; integration and coordination become difficult when

Federica Ceci; Francesca Masciarelli

2010-01-01

82

The 2011 Japanese 9.0 magnitude earthquake: Test of a kinetic energy wave model using coastal configuration and offshore gradient of Earth and beyond  

Microsoft Academic Search

Based on geological investigations of coastal geometry and stratigraphy, offshore gradient variation, wave velocity\\/energy, and quartz grain microtexture analysis of key sites inundated by tsunamis during the Holocene, we have developed a postulated model that could be used to assess modern and ancient onshore environmental conditions during tsunami emplacement. Given that tsunami waves can travel up to ~900km\\/h, the kinetic

William C. Mahaney; James M. Dohm

2011-01-01

83

Sequence stratigraphic analysis of stratigraphic oil traps in the west Siberian Neocomian  

Microsoft Academic Search

Large depositional oil traps (Priob, Sugmut, etc.) have been discovered in the West Siberian Neocomian. Sequence stratigraphic analysis of well logs and seismic reflection profiles demonstrate that reservoirs of these fields represent sands deposited during lowstand, transgressive and highstand phases of relative sea level cycles. Transgressions and regressions advanced in regional longitudinal and local latitudinal directions. The regional longitudinal pattern

O. M. Mkrtchyan; J. M. Armentrout

1996-01-01

84

Offshore Stratigraphic Controls on Salt-Water Intrusion in Los Angeles Area Coastal Aquifers  

Microsoft Academic Search

Ground water is a major component of the water supply for the ~10 million residents of Los Angeles County. Ground water pumping, linked to population growth since the early 1900's, caused water levels to decline, reversed seaward hydraulic gradients in some coastal aquifers, and resulted in salt water intrusion. United States Geological Survey geologists and hydrologists are working cooperatively with

B. D. Edwards; D. J. Ponti; K. D. Ehman; J. C. Tinsley; E. G. Reichard

2002-01-01

85

Exploration concept and characteristic of the dinarides stratigraphic and structural model in the Croatian offshore area  

SciTech Connect

The Dinarides Mesozoic carbonate platform constitutes an extensive paleogeographic unit of the Neo-Tethys platform system. Despite a large sedimentary complex within the platform displaying good hydrocarbon potential, no economic oil accumulations have as yet been discovered. A detailed study of the latest seismic and well data from the Kornati block and other relevant areas suggests, however, that a modified exploration scenario, based on the following elements, could be proposed: (1) Systematic lateral distribution of potential petroliferous facies between the Istrian-Dalmatian marginal zones and the central zone of the external Dinarides. Also, evidence of regular facies changes during platform evolution. (2) Paleotectonic control of varying depositional environments. These range from extremely restricted (anoxic) conditions, to high-energy zones on the platform margins and the edges of intraplatform basins and lagoons. (3) A link between the structural style of the final platform carbonates and the underlying Permian-Triassic halokinetic deposits. This relationship occurred during the Apulia microplate collision and shearing. (4) Differential platform subsidence and burial of potential source rock during platform evolution. Also, post-platform flysch and Molasse sedimentation. (5) Rotational displacement of potential hydrocarbon reservoirs away from the conventional target of exploratory drilling. An acceptance of the above-mentioned elements, particularly the rotation concept, could contribute toward developing a more effective exploration strategy. This should involve seismostratigraphic and other refined exploration methods in many zones of the Neo-Tethys carbonate platform system characterized by similar rotational displacement.

Grandic, S. (Western Geophysical, Isleworth, Middlesex (United Kingdom)); Susterciv, M.; Balas, E. (Ina-Naftaplin, Zagreb (Croatia))

1993-09-01

86

Lake Michigan Offshore Wind Feasibility Assessment  

SciTech Connect

The purpose of this project was to conduct the first comprehensive offshore wind assessment over Lake Michigan and to advance the body of knowledge needed to support future commercial wind energy development on the Great Lakes. The project involved evaluation and selection of emerging wind measurement technology and the permitting, installation and operation of the first mid-lake wind assessment meteorological (MET) facilities in Michigan’s Great Lakes. In addition, the project provided the first opportunity to deploy and field test floating LIDAR and Laser Wind Sensor (LWS) technology, and important research related equipment key to the sitting and permitting of future offshore wind energy development in accordance with public participation guidelines established by the Michigan Great Lakes Wind Council (GLOW). The project created opportunities for public dialogue and community education about offshore wind resource management and continued the dialogue to foster Great Lake wind resource utilization consistent with the focus of the GLOW Council. The technology proved to be effective, affordable, mobile, and the methods of data measurement accurate. The public benefited from a substantial increase in knowledge of the wind resources over Lake Michigan and gained insights about the potential environmental impacts of offshore wind turbine placements in the future. The unique first ever hub height wind resource assessment using LWS technology over water and development of related research data along with the permitting, sitting, and deployment of the WindSentinel MET buoy has captured public attention and has helped to increase awareness of the potential of future offshore wind energy development on the Great Lakes. Specifically, this project supported the acquisition and operation of a WindSentinel (WS) MET wind assessment buoy, and associated research for 549 days over multiple years at three locations on Lake Michigan. Four research objectives were defined for the project including to: 1) test and validate floating LIDAR technology; 2) collect and access offshore wind data; 3) detect and measure bird and bat activity over Lake Michigan; 4) conduct an over water sound propagation study; 5) prepare and offer a college course on offshore energy, and; 6) collect other environmental, bathometric, and atmospheric data. Desk-top research was performed to select anchorage sites and to secure permits to deploy the buoy. The project also collected and analyzed data essential to wind industry investment decision-making including: deploying highly mobile floating equipment to gather offshore wind data; correlating offshore wind data with conventional on-shore MET tower data; and performing studies that can contribute to the advancement and deployment of offshore wind technologies. Related activities included: • Siting, permitting, and deploying an offshore floating MET facility; • Validating the accuracy of floating LWS using near shoreline cup anemometer MET instruments; • Assessment of laser pulse technology (LIDAR) capability to establish hub height measurement of wind conditions at multiple locations on Lake Michigan; • Utilizing an extended-season (9-10 month) strategy to collect hub height wind data and weather conditions on Lake Michigan; • Investigation of technology best suited for wireless data transmission from distant offshore structures; • Conducting field-validated sound propagation study for a hypothetical offshore wind farm from shoreline locations; • Identifying the presence or absence of bird and bat species near wind assessment facilities; • Identifying the presence or absence of benthic and pelagic species near wind assessment facilities; All proposed project activities were completed with the following major findings: • Floating Laser Wind Sensors are capable of high quality measurement and recordings of wind resources. The WindSentinel presented no significant operational or statistical limitations in recording wind data technology at a at a high confidence level as compared to traditional an

Boezaart, Arnold [GVSU; Edmonson, James [GVSU; Standridge, Charles [GVSU; Pervez, Nahid [GVSU; Desai, Neel [University of Michigan; Williams, Bruce [University of Delaware; Clark, Aaron [GVSU; Zeitler, David [GVSU; Kendall, Scott [GVSU; Biddanda, Bopi [GVSU; Steinman, Alan [GVSU; Klatt, Brian [Michigan State University; Gehring, J. L. [Michigan State University; Walter, K. [Michigan State University; Nordman, Erik E. [GVSU

2014-06-30

87

Energy from Offshore Wind: Preprint  

SciTech Connect

This paper provides an overview of the nascent offshore wind energy industry including a status of the commercial offshore industry and the technologies that will be needed for full market development.

Musial, W.; Butterfield, S.; Ram, B.

2006-02-01

88

Sequence stratigraphic controls on reservoir characterization and architecture: case study of the Messinian Abu Madi incised-valley fill, Egypt  

NASA Astrophysics Data System (ADS)

Understanding sequence stratigraphy architecture in the incised-valley is a crucial step to understanding the effect of relative sea level changes on reservoir characterization and architecture. This paper presents a sequence stratigraphic framework of the incised-valley strata within the late Messinian Abu Madi Formation based on seismic and borehole data. Analysis of sand-body distribution reveals that fluvial channel sandstones in the Abu Madi Formation in the Baltim Fields, offshore Nile Delta, Egypt, are not randomly distributed but are predictable in their spatial and stratigraphic position. Elucidation of the distribution of sandstones in the Abu Madi incised-valley fill within a sequence stratigraphic framework allows a better understanding of their characterization and architecture during burial. Strata of the Abu Madi Formation are interpreted to comprise two sequences, which are the most complex stratigraphically; their deposits comprise a complex incised valley fill. The lower sequence (SQ1) consists of a thick incised valley-fill of a Lowstand Systems Tract (LST1)) overlain by a Transgressive Systems Tract (TST1) and Highstand Systems Tract (HST1). The upper sequence (SQ2) contains channel-fill and is interpreted as a LST2 which has a thin sandstone channel deposits. Above this, channel-fill sandstone and related strata with tidal influence delineates the base of TST2, which is overlain by a HST2. Gas reservoirs of the Abu Madi Formation (present-day depth ˜3552 m), the Baltim Fields, Egypt, consist of fluvial lowstand systems tract (LST) sandstones deposited in an incised valley. LST sandstones have a wide range of porosity (15 to 28%) and permeability (1 to 5080mD), which reflect both depositional facies and diagenetic controls. This work demonstrates the value of constraining and evaluating the impact of sequence stratigraphic distribution on reservoir characterization and architecture in incised-valley deposits, and thus has an important impact on reservoir quality evolution in hydrocarbon exploration in such settings.

Abdel-Fattah, Mohamed; Slatt, Roger

2013-12-01

89

Detecting cycles in stratigraphic data: Spectral analysis in the presence of red noise  

NASA Astrophysics Data System (ADS)

We discuss the detection of cyclic signals in stratigraphic `time series' using spectral methods. The dominant source of variance in the stratigraphic record is red noise, which greatly complicates the process of searching for weak periodic signals. We highlight two issues that are more significant than generally appreciated. The first is the lack of a correction for `multiple tests' - many independent frequencies are examined for periods but using a significance test appropriate for examination of a single frequency. The second problem is the poor choice of null hypothesis used to model the spectrum of non-periodic variations. Stratigraphers commonly assume the noise is a first-order autoregressive process - the AR(1) model - which in practice often gives a very poor match to real data; a fact that goes largely unnoticed because model checking is rarely performed. These problems have the effect of raising the number of false positives far above the expected rate, to the extent that the literature on spatial stratigraphic cycles is dominated by false positives. In turn these will distort the construction of astronomically calibrated timescales, lead to inflated estimates of the physical significance of deterministic forcing of the climate and depositional processes in the pre-Neogene, and may even bias models of solar system dynamics on very long timescales. We make suggestions for controlling the false positive rate, and emphasize the value of Monte Carlo simulations to validate and calibrate analysis methods.

Vaughan, S.; Bailey, R. J.; Smith, D. G.

2011-12-01

90

Stratigraphic data for wells at and near the Idaho National Engineering Laboratory, Idaho  

SciTech Connect

A stratigraphic data base containing 230 stratigraphic units in 333 wells was constructed for deposits that make up the unsaturated zone and the Snake River Plain aquifer at and near INEL in eastern Idaho. Stratigraphic units, which were identified and correlated using data from numerous outcrops, 26 continuous cores, and 328 natural-gamma logs available in Dec. 1993, include 121 basalt-flow groups, 102 sedimentary interbeds, 6 andesite-flow groups, and 1 rhyolite dome. By volume, basalt flows make up about 90% of the deposits underlying most of this 890 mi{sup 2} area. Basalt, sediment, andesite, and rhyolite were identified from outcrops and cores that were selectively evaluated. Stratigraphic units were correlated using these data and natural-gamma logs. Best correlations were for basalt and sediment at Test Area North, the Naval Reactors Area, the Test Reactor Area, ICPP, and the Radioactive Waste Management Complex (RWMC), where most cores and 2/3 of the logs were obtained. Correlations range from good at the RWMC to uncertain the eastern half of the study area. A computer diskette containing the data is included.

Anderson, S.R.; Ackerman, D.J.; Liszewski, M.J. [Geological Survey, Washington, DC (United States); Frieburger, R.M. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

1996-05-01

91

Offshore wind farm layout optimization  

Microsoft Academic Search

Offshore wind energy technology is maturing in Europe and is poised to make a significant contribution to the U.S. energy production portfolio. Building on the knowledge the wind industry has gained to date, this dissertation investigates the influences of different site conditions on offshore wind farm micrositing---the layout of individual turbines within the boundaries of a wind farm. For offshore

Christopher Neil Elkinton

2007-01-01

92

Immigration, Offshoring and American Jobs  

Microsoft Academic Search

How do offshoring and immigration affect the employment of native workers? What kinds of jobs suffer, or benefit, most from the competition created by offshore and immigrant workers? In contrast to the existing literature that has mostly looked at the effects of offshoring and immigration separately, we argue that one can gain useful insights by jointly investigating the interactions among

Gianmarco I. P. Ottaviano; Giovanni Peri; Greg C. Wright

2012-01-01

93

The geotechnical centrifuge in offshore engineering  

SciTech Connect

One of the greatest needs in offshore geotechnical engineering is for large scale test measurements on which to calibrate design procedures. The geotechnical centrifuge offers at least a partial remedy. Because it allows one to properly simulate stresses, it is a legitimate, relatively inexpensive option to full scale field testing. As such it is a valuable technique and can be an excellent complement to laboratory tests, 1-g model tests and numerical analyses. However, it has not been widely used by industry even though the capability has existed for almost thirty years. This paper argues that this technology should gain acceptance beyond the research community. The paper presents an overview of centrifuge principles, philosophies of use, and limitations of the technique. For illustration, several actual applications of centrifuge testing for complex offshore problems are described. Results are shown to provide important insights into prototype behavior and to agree well with full scale measurements where these are available.

Murff, J.D.

1996-12-31

94

Paleontological Events: Stratigraphic, Ecologic, and Evolutionary Implications  

NASA Astrophysics Data System (ADS)

A most active area of modern paleontology concerns the causes and consequences of global mass extinction events. Fueled by wide public interest in extinction of the dinosaurs and debate among geologists over the causes of this event, paleontologists have scrutinized the geologic record of extinction events. Volume after volume has addressed these prominent extinction events. Far less study, and an order of magnitude less paper, have been devoted to the causes of local and regional paleontological events such as local extinctions and incursions even though they are far more common and can be equally dramatic.Many sedimentary geologists have observed horizons of marine sedimentary rocks unusually enriched in fossil remains. However, few of us stop to consider their significance.Paleontological Events: Stratigraphic, Ecologic, and Evolutionary Implications showcases 20 state-of-the-art papers that explore the causes of short-term and longer-term bioevents that have left behind remarkable paleontological records.

Bralower, Timothy J.

95

StratiGraph Tool: Matrix Stratifications in Control Applications  

E-print Network

StratiGraph Tool: Matrix Stratifications in Control Applications Bo K°agstr¨om , Stefan Johansson and visualizing closure hierarchy graphs associated with different orbit and bundle stratifications is presented structures, orbit, bundle, closure hierarchy, cover relations, StratiGraph. 1 Introduction Dynamical systems

Johansson, Stefan

96

Offshore Renewable Energy Solutions  

E-print Network

, and advances in wave forecasting will support the next generation of deep-water floating devices. Enablers We helping you to deliver offshore #12;Eco-innovation Our input into new designs for floating and deep structures. We can advise on the use of novel foundat

97

Combination offshore drilling rig  

Microsoft Academic Search

An offshore drilling rig is described for use in drilling into a formation below a body of water comprising a barge hull having a drilling slot extending inwardly from the peripheral boundary of the barge hull, means for supporting the barge hull in a position above the water, a cantilever structure mounted on the barge hull and movable horizontally with

D. B. Lorenz; J. S. II Laid

1986-01-01

98

Reinforced concrete offshore platform  

Microsoft Academic Search

A reinforced concrete offshore platform is described comprising a honeycomb foundation (A), a supporting structure (B) and an above-surface section (C) carrying appropriate equipment. The honeycomb foundation (A) and the supporting structure (B) are made of prefabricated reinforced concrete elements which are polyhedral hollow prisms arranged with gaps between the external sides thereof and joined by a system of prestressed

J. P. Martyshenko; S. J. Martyshenko; J. S. Kotelnikov; E. G. Kutukhtin; M. S. Petrosian; N. I. Ilyasova; J. S. Volkov; A. M. Vardanian

1987-01-01

99

Offshore pollution prevention  

Microsoft Academic Search

A complete system for removing oil from produced water and deck drain fluids in an offshore facility includes a surge settler which receives the produced water from a three-phase separator. In the surge settler, the produced water flows crosswise through a corrugated plate assembly to separate free oil and solids from the produced water. A portion of the produced water

Favret; U. B. Jr

1984-01-01

100

Salt Repository Project site study plan for stratigraphic boreholes: Revision 1, December 18, 1987  

SciTech Connect

This site study describes the Stratigraphic Boreholes field work to be conducted during the early stages of Site Characterization at the Deaf Smith County, Texas site. The field program has been designed to provide data useful in addressing information/data needs resulting from Federal/State/local regulations, and repository program requirements. Four Stratigraphic Holes will be drilled near the perimeter of the site to document the subsurface geologic conditions in that area and to provide data necessary for design and construction of the Exploratory Shaft Facilities. Continuous samples will be recovered from the ground surface to the total depth of each sell. Geophysical well logs will provide additional coverage of the stratigraphic section. In-situ down hole testing will include short term hydrologic tests and hydraulic fracture tests to provide information on deep groundwater characteristics and regional stress patterns, respectively. Field methods/tests are chosen that provide the best or only means of obtaining the required data. The Salt Repository Project (SRP) Networks specify the schedule which the program will operate. The Technical Services Contractor is responsible for conducting the field program of drilling and testing. Samples and data will be handled and reported in accordance with established SRP procedures. A quality assurance program will be utilized to assure that activities affecting quality are performed correctly and that the appropriate documentation is maintained. 30 refs., 13 figs., 4 tabs.

Not Available

1987-12-18

101

Geological & Geophysical findings from seismic, well log and core data for marine gas hydrate deposits at the 1st offshore methane hydrate production test site in the eastern Nankai Trough, offshore Japan: An overview  

NASA Astrophysics Data System (ADS)

In order to evaluate productivity of gas from marine gas hydrate by the depressurization method, Japan Oil, Gas and Metals National Corporation is planning to conduct a full-scale production test in early 2013 at the AT1 site in the north slope of Daini-Atsumi Knoll in the eastern Nankai Trough, Japan. The test location was determined using the combination of detailed 3D seismic reflection pattern analysis, high-density velocity analysis, and P-impedance inversion analysis, which were calibrated using well log data obtained in 2004. At the AT1 site, one production well (AT1-P) and two monitoring wells (AT1-MC and MT1) were drilled from February to March 2012, followed by 1 coring well (AT1-C) from June to July 2012. An extensive logging program with logging while drilling (LWD) and wireline-logging tools, such as GeoVISION (resistivity image), EcoScope (neutron/density porosity, mineral spectroscopy etc.), SonicScanner (Advanced Sonic tool), CMR/ProVISION (Nuclear Magnetic Resonance Tools), XPT (formation pressure, fluid mobility), and IsolationScanner (ultrasonic cement evaluation tools) was conducted at AT1-MC well to evaluate physical reservoir properties of gas hydrate-bearing sediments, to determine production test interval in 2013, and to evaluate cement bonding. Methane hydrate concentrated zone (MHCZ) confirmed by the well logging at AT1-MC was thin turbidites (tens of centimeters to few meters) with 60 m of gross thickness, which is composed of lobe type sequences in the upper part of it and channel sand sequences in the lower part. The gross thickness of MHCZ in the well is thicker than previous wells in 2004 (A1, 45 m) located around 150 m northeast, indicating that the prediction given by seismic inversion analysis was reasonable. Well-to-well correlation between AT1-MC and MT1 wells within 40 m distance exhibited that lateral continuity of these sand layers (upper part of reservoir) are fairly good, which representing ideal reservoir for the production test. The XPT measurement results showed approximately 0.1 to several mD of water permeability in both the hydrate-bearing formation and seal formation, although there are some variations in measured values. However, the comparison of these results with permeability estimated by NMR log showed significant discrepancy (more than one order of difference), which suggests that it is necessary to have further investigation considering the difference in scale, measurement direction (Kh or Kv), and calibration methodology by pressure core data. In order to obtain basic reservoir/seal properties for the well log calibration within and above production test interval, pressure coring using Hybrid Pressure Coring System (Hybrid PCS) and also non-destructive core analysis onboard using Pressure Core Analysis and Transfer System (PCATS) were conducted for 60 m interval in AT1-C, which located about 10 m northeast of AT1-MC. Finally, integrated reservoir characterization based on well-log and pressure core data was conducted to predict and optimize the flow rate of upcoming production test.

Fujii, T.; Noguchi, S.; Takayama, T.; Suzuki, K.; Yamamoto, K.

2012-12-01

102

Economics of Developing Hot Stratigraphic Reservoirs  

SciTech Connect

Stratigraphic geothermal reservoirs at 3 – 4 km depth in high heat-flow basins are capable of sustaining 100 MW-scale power plants at about 10 c/kWh. This paper examines the impacts on the levelized cost of electricity (LCOE) of reservoir depth and temperature, reservoir productivity, and drillhole/casing options. For a reservoir at 3 km depth with a moderate productivity index by hydrothermal reservoir standards (about 50 L/s/MPa, 5.6 gpm/psi), an LCOE of 10c/kWh requires the reservoir to be at about 200°C. This is the upper temperature limit for pumps. The calculations assume standard hydrothermal drilling costs, with the production interval completed with a 7 inch liner in an 8.5 inch hole. If a reservoir at 4 km depth has excellent permeability characteristics with a productivity index of 100 L/s/MPa (11.3 gpm/psi), then the LCOE is about 11 c/kWh assuming the temperature decline rate with development is not excessive (< 1%/y, with first thermal breakthrough delayed by about 10 years). Completing wells with modest horizontal legs (e.g. several hundred meters) may be important for improving well productivity because of the naturally high, sub-horizontal permeability in this type of reservoir. Reducing the injector/producer well ratio may also be cost-effective if the injectors are drilled as larger holes.

Greg Mines; Hillary Hanson; Rick Allis; Joseph Moore

2014-09-01

103

America's Offshore Refugee Camps  

Microsoft Academic Search

America's offshore refugee camps rank. among the most startling, yet invisible, features of United States foreign policy in the post-Cold War era. Since 1991, our Government has almost continuously maintained tent cities holding thousands of men, women, and children, surrounded by rolls of razor-barbed wire, amid the sweltering heat of the U.S. Naval Base at Guantanamo Bay, Cuba, and the

Harold Hongju Koh

1994-01-01

104

Offshore Wind Turbines - Estimated Noise from Offshore Wind Turbine, Monhegan Island, Maine: Environmental Effects of Offshore Wind Energy Development  

SciTech Connect

Deep C Wind, a consortium headed by the University of Maine will test the first U.S. offshore wind platforms in 2012. In advance of final siting and permitting of the test turbines off Monhegan Island, residents of the island off Maine require reassurance that the noise levels from the test turbines will not disturb them. Pacific Northwest National Laboratory, at the request of the University of Maine, and with the support of the U.S. Department of Energy Wind Program, modeled the acoustic output of the planned test turbines.

Aker, Pamela M.; Jones, Anthony M.; Copping, Andrea E.

2010-11-23

105

Electrokinetic improvement of offshore foundations  

NASA Astrophysics Data System (ADS)

Offshore and near-shore structures for energy exploration and production, harbour work and other facilities are often situated on very soft marine clay deposits that have shear strengths of a few kilopascals. The design of foundations embedded in these soft deposits often poses a challenge for geotechnical engineers, i.e., to satisfy the bearing capacity requirement, while at the same time minimizing the embedment depth and dimensions of the foundation due to cost considerations. The present study investigates the possibility of using electrokinetics to strengthen the soil adjacent to skirted foundations embedded in soft marine deposits and, thus, to improve the load carrying capacity of the foundations. The innovative feature of this approach as compared to soil improvement methods commonly adopted in practice is that the focus of strengthening is on the interface between the soil and embedded foundation, in terms of enhancement of adhesion and cementation. The thesis presents a summary of the method and results of a series of electrokinetic tests conducted on natural and simulated marine clays in small-scale and large-scale laboratory testing facilities. Steel plates and steel cylinders are used to simulate skirted foundations. A low dc voltage is applied via steel electrodes installed around the foundation models. The effects of electrokinetics are evaluated through changes in the geotechnical properties of the soil and load carrying capacities of the foundation model after treatment. The results demonstrate that the load carrying capacity of the skirted foundation model and the undrained shear strength of the adjacent soil increase by a factor of three after electrokinetic treatment. The clay adheres strongly to the inside and outside walls of the foundation model, indicating bonding occurs between the soil and steel after treatment. The treatment increases the soil undrained modulus and also induces a preconsolidation pressure of the remoulded clay, thereby reducing potential settlement of the foundation. The new technology described in this thesis has potential application in offshore engineering for increasing the load carrying capacity of skirted foundations installed in soft clayey sediments, as well as for rehabilitation of existing offshore structures.

Micic, Silvana

106

The offshore-ring: A new system design for the open ocean aquaculture of macroalgae  

Microsoft Academic Search

Mass culture of benthic macroalgae under rough offshore conditions in the North Sea requires rigid culture support systems that cannot only withstand rough weather conditions but can also be effectively handled while at the same time retain the cultured species. Various carrier constructions and different mooring systems were tested. Laminaria saccharina grew on all of these carriers with initially high

Bela Hieronymus Buck; Cornelia Maria Buchholz

2004-01-01

107

Stable isotopes in late Pennsylvanian brachiopods: stratigraphic and paleoenvironmental implications  

E-print Network

STABLE ISOTOPES IN LATE PENNSYLVANIAN BRACHIOPODS: STRATIGRAPHIC AND PALEOENVIRONMENTAL IMPLICATIONS A Thesis by CHUANLUN ZHANG Submitted to the Office of Graduate Studies of Texas A%M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1989 Major Subject: Geology Stable Isotopes in Late Pennsylvanian Brachiopods: Stratigraphic and Paleoenvironmental Implications A Thesis by CHUANLUN ZHANG Approved as to the style and content by: Ethan L...

Zhang, Chuanlun

1989-01-01

108

Reinforced concrete offshore platform  

SciTech Connect

A reinforced concrete offshore platform is described comprising a honeycomb foundation (A), a supporting structure (B) and an above-surface section (C) carrying appropriate equipment. The honeycomb foundation (A) and the supporting structure (B) are made of prefabricated reinforced concrete elements which are polyhedral hollow prisms arranged with gaps between the external sides thereof and joined by a system of prestressed vertical diaphragm walls and horizontal diaphragm walls formed by pre-tensioning reinforcing bars placed in the gaps between the faces of the prisms and casting in-situ the gaps later on.

Martyshenko, J.P.; Martyshenko, S.J.; Kotelnikov, J.S.; Kutukhtin, E.G.; Petrosian, M.S.; Ilyasova, N.I.; Volkov, J.S.; Vardanian, A.M.

1987-10-20

109

Application of soil-stratigraphic techniques to engineering geology  

SciTech Connect

Soil-stratigraphic techniques are being increasingly applied to engineeringgeological investigations for siting liquified natural gas (LNG) facilities, nuclear reactors, dams, and other critical structures. Soil (pedological) profiles in Quaternary sections are useful to ascertain the approximate age of sitearea sediments, to reconstruct local geomorphic history, to date the last movement of faults, and in some cases to determine recurrence intervals of displacements associated with faults or large mass-movements. Exemplified in geotechnical investigations for a proposed LNG terminal near Point Conception (Little Cojo Bay), California, soil stratigraphy was employed to date last displacement of site-area faults, to estimate age of marine platforms, and to help reconstruct regional geomorphic history. Similarly, at the General Electric Test Reactor (GETR) site near Livermore (Vallecitos), California, soil stratigraphy was instrumental to date last displacement and recurrence of site-area slip surfaces engendered either by tectonic or by mass-wasting processes. Datable markers included four, strongly-developed buried paleosols, each of which marked epochs of regional landscape stability during the Quaternary.

Shlemon, R.J.

1985-05-01

110

Offshore sand resources for coastal erosion control in Louisiana  

SciTech Connect

An inventory of existing geophysical data supplemented by more than 15,000 km of high-resolution seismic profiles and 400 vibracores collected cooperatively by the Louisiana Geological Survey and US Geological Survey since 1981 indicates that a wide range of aggregate minerals occurs on the continental shelf in a variety of depositional settings. The distribution of these deposits is controlled by the geometry of the preexisting fluvial and deltaic channel systems and the stratigraphic signature of the Holocene Transgression across these features. The geology of coastal and offshore Louisiana is tied to the depositional history of the Mississippi River. Offshore of the delta plain, five types of aggregate sources can be identified: inner shelf shoals, submerged barrier islands, tidal inlets, distributary channels, and barrier platforms. This paper describes the geology of offshore Louisiana, the available geophysical data sets, and the distribution of aggregate mineral resources. On the continental shelf of the Mississippi River delta plain, two extensive seismic survey grids have been developed by the Louisiana Geological Survey and US Geological Survey. The most prospective resources found are the huge sand bodies of Ship Shoal and associated distributaries, Cat Island Pass tidal channels and associated tidal deltas, and Barataria Pass/Grand Terre tidal channels and associated tidal deltas. East of the mouth of the Mississippi River are the Chandeleur Islands, where LGS identified seven major sand resource targets, truncated barrier-spit and tidal inlet deposits, submerged beach ridges, and distributaries associated with abandoned St. Bernard delta complexes. Abundant sand resources can be found in offshore Louisiana. Many of the sand bodies contain heavy minerals, but their concentration and distribution is unknown. Other potential sand resources not yet adequately explored include Sabine Bank, the Outer Shoal, and the St. Bernard shoal.

Ramsey, K.E.; Penland, S.; McBride, R.A. (Louisiana Geological Survey, Baton Rouge (USA)); Suter, J.R. (Exxon Production Research, Houston, TX (USA)); Williams, J. (Geological Survey, Reston, VA (USA))

1990-09-01

111

Offshore sand for reinforced concrete  

Microsoft Academic Search

A figure of 0.075% by weight of sand was arrived at as a safe limit for allowable Cl? ion content in offshore sand for OPC based reinforced concrete. A 2m high sand column was fabricated for checking the effects of natural drainage and simulated rain on the chloride levels in offshore sand, and the action of even 80mm of rain

W. P. S. Dias; G. A. P. S. N. Seneviratne; S. M. A. Nanayakkara

2008-01-01

112

Offshore Drilling From Ice Platforms  

Microsoft Academic Search

This paper describes a method successfully developed for drilling offshore from a floating ice platform. This method has allowed exploration wells to be drilled economically in the Canadian Arctic islands without years of waiting for sophisticated offshore drilling vessels to be developed, financed, and built to operate in the severe ice conditions prevalent in the area.

G. L. Hood; H. J. Strain; D. J. Baudais

1976-01-01

113

Ice protection of offshore platforms  

Microsoft Academic Search

Climate change-induced reduction in the extent and duration of sea ice cover, as well as an increase in energy demands, has caused renewed interest in exploring and drilling for oil in Arctic waters. Superstructure icing from sea spray and atmospheric icing in the Arctic may impact offshore platform operations. Though icing has not caused the loss of an offshore platform,

Charles C. Ryerson

2011-01-01

114

Structure, stratigraphy and petroleum geology of the south east Nam Con Son Basin, offshore Vietnam  

SciTech Connect

Recent exploration of the south east Nam Con Son Basin, offshore Vietnam, by BP in alliance with Statoil has involved acquisition of new seismic and well data. These new data have allowed re-evaluation of the tectono-stratigraphic development and petroleum geology, and have provided additional constraints on the regional tectonic evolution. The offshore Vietnamese basins have evolved in response to the complex relative motions of Indochina, Peninsular Malaysia, Borneo and the South China Sea during the Cenozoic. On the regional scale these motions have been accommodated by strike-slip fault development, rifting and contraction. In the Nam Con Son Basin these motions have interacted in different ways from the Palaeogene to recent. Two rifting episodes are recognized; a Palaeogene phase dominated by E-W trending extensional faults, and a Miocene phase dominated by N-S to NE-SW trending faults. The structural evolution is complicated by a pulse of mild contraction during the Middle Miocene. The sedimentary fill of the basin evolves from continental fluvio-lacustrine in the Palaeogene through to fully marine following the second phase of rifting in the Miocene. This pulsed structural and stratigraphic evolution has resulted in basinwide deposition of source, reservoir and seal facies, and produced a variety of potential trapping styles. This paper describes the hydrocarbon habitat of the south east Nam Con Son Basin within the context of the regional tectono-stratigraphic model.

Fraser, A.J.; Matthews, S.J.; Lowe, S.; Todd, S.P.; Simon, P. Peel, F.J. [BP Exploration Operating Co., Ltd., Uxbridge (United Kingdom)

1996-12-31

115

Structure, stratigraphy and petroleum geology of the south east Nam Con Son Basin, offshore Vietnam  

SciTech Connect

Recent exploration of the south east Nam Con Son Basin, offshore Vietnam, by BP in alliance with Statoil has involved acquisition of new seismic and well data. These new data have allowed re-evaluation of the tectono-stratigraphic development and petroleum geology, and have provided additional constraints on the regional tectonic evolution. The offshore Vietnamese basins have evolved in response to the complex relative motions of Indochina, Peninsular Malaysia, Borneo and the South China Sea during the Cenozoic. On the regional scale these motions have been accommodated by strike-slip fault development, rifting and contraction. In the Nam Con Son Basin these motions have interacted in different ways from the Palaeogene to recent. Two rifting episodes are recognized; a Palaeogene phase dominated by E-W trending extensional faults, and a Miocene phase dominated by N-S to NE-SW trending faults. The structural evolution is complicated by a pulse of mild contraction during the Middle Miocene. The sedimentary fill of the basin evolves from continental fluvio-lacustrine in the Palaeogene through to fully marine following the second phase of rifting in the Miocene. This pulsed structural and stratigraphic evolution has resulted in basinwide deposition of source, reservoir and seal facies, and produced a variety of potential trapping styles. This paper describes the hydrocarbon habitat of the south east Nam Con Son Basin within the context of the regional tectono-stratigraphic model.

Fraser, A.J.; Matthews, S.J.; Lowe, S.; Todd, S.P.; Simon, P. Peel, F.J. (BP Exploration Operating Co., Ltd., Uxbridge (United Kingdom))

1996-01-01

116

Lower Jurassic sediments from the Rhar Roubane Mountains (Western Algeria): Stratigraphic precisions and synsedimentary block-faulting  

NASA Astrophysics Data System (ADS)

During the Lower Jurassic, the stratigraphic and palaeogeographic fluctuations of facies and thickness as well as the existence of stratigraphic gaps in the central and eastern parts of the Rhar Roubane Horst are controlled by the pre-Lower Jurassic palaeotopography as well as the evolution of the subsidence in the different blocks and probably tilting of blocks. This geodynamic context is placed in a general framework of evolution of carbonate rocks of the Tlemcen Domain, characterised by an episode of filling during the Early Pliensbachian followed by a deepening episode from the Late Pliensbachian onward. Four facies associations were recognised through macroscopic and microscopic analyses. Facies association-A corresponds to tidal platform environments, represented by the Zaïlou Limestones Fm. Facies association-B entails biomicrite and biosparite from the shoreface environment represented by the Tisseddoura Limestones Fm in the Central Rhar Roubane Horst and the Pseudonodular Limestones Fm at Eastern Rhar Roubane Horst. Facies association-C comprises a condensed succession rich in ammonoids represented by the Beni Bahdel Ferruginous Limestones Fm, indicating an upper offshore environment. Finally, facies association-D is a marl-limestone rhythmite with abundant cephalopods, corresponding to the Bayada Beds Fm and representing a lower offshore environment. The maximum depth is that of the Toarcian deposits of the Bayada Beds Fm (Area of Tleta). The central part of the Rhar Roubane Horst constituted a topographic barrier that controlled geometry, thickness variation and facies development during the Early Jurassic, evidenced by characteristic deposits with varying thickness and stratigraphic gaps. The Eastern Rhar Roubane Horst reveals such changes in facies, thickness and stratigraphic gaps to be a sedimentary response to the extensional tectonics of tilted blocks. Subsidence in the different areas of the Eastern Rhar Roubane changed during the Pliensbachian to Middle Toarcian, and persistent sectors became subsiding zones or vice versa. A comparison of Rhar Roubane sucessions with neighbouring domains in the Northern Gondwana Palaeomargin, from Morocco to Tunisia, evidences great similarities in the deepening evolution of sedimentation, yet with diachronic platform submergence.

Marok, Abbas; Reolid, Matías

2012-11-01

117

Towers for Offshore Wind Turbines  

NASA Astrophysics Data System (ADS)

Increasing energy demand coupled with pollution free production of energy has found a viable solution in wind energy. Land based windmills have been utilized for power generation for more than two thousand years. In modern times wind generated power has become popular in many countries. Offshore wind turbines are being used in a number of countries to tap the energy from wind over the oceans and convert to electric energy. The advantages of offshore wind turbines as compared to land are that offshore winds flow at higher speed than onshore winds and the more available space. In some land based settings, for better efficiency, turbines are separated as much as 10 rotor diameters from each other. In offshore applications where only two wind directions are likely to predominate, the distances between the turbines arranged in a line can be shortened to as little as two or four rotor diameters. Today, more than a dozen offshore European wind facilities with turbine ratings of 450 kw to 3.6 MW exist offshore in very shallow waters of 5 to 12 m. Compared to onshore wind turbines, offshore wind turbines are bigger and the tower height in offshore are in the range of 60 to 80 m. The water depths in oceans where offshore turbines can be located are within 30 m. However as the distance from land increases, the costs of building and maintaining the turbines and transmitting the power back to shore also increase sharply. The objective of this paper is to review the parameters of design for the maximum efficiency of offshore wind turbines and to develop types offshore towers to support the wind turbines. The methodology of design of offshore towers to support the wind turbine would be given and the environmental loads for the design of the towers would be calculated for specific cases. The marine corrosion on the towers and the methods to control the corrosion also would be briefly presented. As the wind speeds tend to increase with distance from the shore, turbines build father offshore will be able to capture more wind energy. Currently two types of towers are considered. Cylindrical tubular structures and truss type structures. But truss type structures have less weight and flexibility in design. The construction of the offshore towers to harness the wind energy is also presented. The results will include the calculation of wind and wave forces on the tower and the design details for the tower.

Kurian, V. J.; Narayanan, S. P.; Ganapathy, C.

2010-06-01

118

Petroleum Systems of South Kara Basin: 3D stratigraphic simulation and basin modeling results  

NASA Astrophysics Data System (ADS)

Petroleum systems of South Kara Basin are still poorly studied and hydrocarbon resource estimates vary depending on geological models and understanding of the basin evolution. The main purpose of the regional studies of South Kara Basin was to produce a consistent model, which would be able to explain the existence of the fields discovered in the area as well as to determine the most favorable hydrocarbon accumulation zones in the study area for further exploration. In the study 3D stratigraphic simulation and basin modeling of South Kara Basin was carried out. The stratigraphic simulation results, along with geological, geophysical and geochemical data for the inland areas of Yamal and Gydan peninsulas and South Kara islands enabled to predict the lithological composition and distribution of source rocks, reservoirs and seals in the Kara Sea offshore area. Based on the basin modeling results hydrocarbon accumulations may occur in the reservoir facies of the wide stratigraphic range from Jurrasic to Cretaceous. The main source for the hydrocarbons, accumulated in the South Kara Basin Neocomian and Cenomanian reservoirs are the J3-K1 (the northward extension of Bazhenov Formation and its analogs of West Siberia), as well as J1 and probably J2 shales with predominantly marine type of kerogen (type II). Thermal and burial history restorations show that Lower Cretaceous (Aptian-Albian) sediments enriched with terrigenous organic matter (kerogen of type III) and containing coaly layers could not produce the hydrocarbon volumes to fill the giant Rusanovskoye and Leningradskoye gas-condensate fields as the K1 source rocks are not mature enough. The modeling results, in particular, suggest that the geologic conditions in the South Kara Basin are favorable for further discoveries of giant fields. Although gas accumulations are predominating in the basin, oil-and-gascondensate fields (not a pure oil fields though) with sufficient part of liquid hydrocarbons might be present in particular areas where the source rocks maturation was favorable. Further refining of the model will be possible as soon as new exploration wells will be drilled and new geological, geochemical and seismic data acquired.

Malysheva, S.; Vasilyev, V.; Verzhbitsky, V.; Ananyev, V.; Murzin, R.; Komissarov, D.; Kosenkova, N.; Roslov, Yu.

2012-04-01

119

Mobile offshore drilling units for frontier areas  

SciTech Connect

As response to the expanded Five-Year Offshore Leasing Plan a tremendous amount of construction and expansion has been underway in the offshore industry. This presentation is intended to provide a sampling of the mobile offshore drilling units which are expected to be used in frontier areas offshore Alaska.

Kelly, P.L.

1983-04-01

120

Bahrain's offshore banking center  

SciTech Connect

The economic effects of Bahrain's schemes for licensing offshore banking units (OBUs) were the immediate response of major international banks and the financial services the banking center has rendered by improving regional money and exchange markets at a time when a Middle East link was needed to service the increasing demand for oil-wealth banking services. Bahrain's leadership also created a favorable climate. Aggressive competition from banks in Kuwait and Saudi Arabia have caused some friction, but informal supervision by the Bahrain Monetary Agency (BMA) should be able to avoid serious difficulty. Bahrain's success required a banking infrastructure, a free-enterprise system, a willingness to maintain banking standards, a country small enough to benefit directly from OBU income, and a gap in nearby competing centers. 39 references, 1 figure, 5 tables. (DCK)

Gerakis, A.S.; Roncesvalles, O.

1983-01-01

121

Polar Layered Deposits: Preliminary Stratigraphic Assessment from MGS Observations  

NASA Technical Reports Server (NTRS)

Global and hemispheric climatic, volcanic and impact events that modulated the formation of the Martian polar layered deposits can be revealed by detailed stratigraphic analyses of well-exposed sequences of those layers. Complete three-dimensional Mars Orbiting Laser Altimeter (MOLA) topography of the north and south polar deposits is now available, and very abundant Mars Orbiter Camera (MOC) imagery that is well calibrated is becoming available. This paper presents an assessment of the polar stratigraphic potential based on observations from Mars Global Surveyor (MGS) mapping cycles through M7. Additional information can be found in the original extended abstract.

Murray, B. C.; Byrne, S.; Danielson, G. E.; Herkenhoff, K. E.; Soderblom, L. A.; Zuber, M. T.

2000-01-01

122

Polar Layered Deposits: Preliminary Stratigraphic Assessment from MGS Observations  

NASA Astrophysics Data System (ADS)

Global and hemispheric climatic, volcanic and impact events that modulated the formation of the Martian polar layered deposits can be revealed by detailed stratigraphic analyses of well-exposed sequences of those layers. Complete three-dimensional Mars Orbiting Laser Altimeter (MOLA) topography of the north and south polar deposits is now available, and very abundant Mars Orbiter Camera (MOC) imagery that is well calibrated is becoming available. This paper presents an assessment of the polar stratigraphic potential based on observations from Mars Global Surveyor (MGS) mapping cycles through M7. Additional information can be found in the original extended abstract.

Murray, B. C.; Byrne, S.; Danielson, G. E.; Herkenhoff, K. E.; Soderblom, L. A.; Zuber, M. T.

2000-08-01

123

Arctic and offshore research: Technology status report  

SciTech Connect

This report describes the state of technology relative to the production of oil and gas in the Arctic. It discusses the technical issues that warrant investigation, and focuses on the current Department of Energy supported activities. Major accomplishments during the last year include the following: The Arctic and Offshore Research Information System (AORIS) was planned with industry survey recommendations incorporated. It contains a directory of 85 Arctic databases, a bibliographic component of over 7,000 citations, and a data component of about 300 data sets on sea ice characteristics. Seven position, pressure, and temperature buoys were deployed on ice islands (up to 3 by 6 miles in size) drifting off Ellesmere Island. Ice island movement, as much as 340 miles southwest of the Ward Hunt Ice Shelf during the last 4 years, represents a potential hazard to Arctic offshore structures in the Alaskan Beaufort Sea. The redesigned Seafloor Earthquake Measurement System (SEMS II) was deployed near Shell's Ellen-Elly platforms, about 10 miles offshore of Long Beach, California. The SEMS monitored the July 1986 southern California earthquakes. This was the first time earthquakes were simultaneouslly monitored by sensors located on land, aboard offshore platforms, and beneath the seafloor. Sea spray ice bond shear strength to various structural and protective coatings has been determined. The polyethylene coating demonstrated the most potential for rapid shedding of spray ice by gravity loading. Measurements of temperatures and salinities were completed as part of a pilot test to (1) detect seasonal conditions at the water-seabed interface, and (2) determine how they influence permafrost growth in the coastal waters of the Beaufort Sea. The temperatures and computed freezing point data suggest that seasonal seabed freezing can occur most of the winter. 13 refs., 14 figs., 4 tabs.

Not Available

1988-01-01

124

Offshoring and Directed Technical Change  

E-print Network

To study the short-run and long-run implications on wage inequality, we introduce directed technical change into a Ricardian model of offshoring. A unique final good is produced by combining a skilled and an unskilled ...

Acemoglu, Daron

2012-11-24

125

Methane Seeps along Offshore Virginia  

USGS Multimedia Gallery

Numerous distinct methane streams emanating from the seafloor at an upper slope (< 500 m water depth) cold seep site offshore Virginia. Image courtesy of NOAA Okeanos Explorer Program, 2013 Northeast U.S. Canyons Expedition....

126

Cathodic protection of offshore pipelines  

Microsoft Academic Search

The cost of cathodic protection for minimizing corrosion in offshore natural gas transmission pipelines is insignificant compared with the overall pipeline cost. The cathodic system sometimes remains a last-minute design and procurement item, installed with little supervision and rarely checked until the pipeline has been in service for several years. Typical offshore cathodic-protection-system design parameters are (1) sacrificial zinc anodes

1981-01-01

127

Response of offshore cultivated Laminaria saccharina to hydrodynamic forcing in the North Sea  

Microsoft Academic Search

The aim of the presented investigation was to test the sensibility of macroalgal aquaculture in offshore wind farms in the North Sea and to find arguments for the choice of appropriate sites among the planned wind farms. Based on experience with an offshore aquaculture farm of Laminaria saccharina conducted in 2002, we assessed the maximum hydrodynamic forces affecting farmed algae

Bela Hieronymus Buck; Cornelia Maria Buchholz

2005-01-01

128

Problems unique to offshore measurement  

SciTech Connect

Most of us have arrived at this meeting in some kind of company provided transportation. This is supplied in order for us to do our assigned jobs. These may be trucks, or cars, or even helicopters, and maybe boats. All who are involved in the offshore industry know that transportation is the cost costly of all. The helicopter bill for our company is a bill which costs us somewhere in the 9 million dollar range. Since this costs us so much, we are constantly looking at ways to reduce this. The helicopters we use cost us $510.00 a flying hour plus $28,000.00 a month for lease. These helicopters fly in the neighborhood of 140 miles per hour. You can quickly see how fast the cost can climb. We have two technicians, along with a pilot, and approx. 400 lbs of test gear and spare parts. You have to carry all you think you will need for the day`s activities because it`s a long and costly trip to go pick up some gasket material or an orifice plate.

Young, J.G. [ANR Pipeline Co., Lafayette, LA (United States)

1995-12-01

129

Seismic lateral prediction in chalky limestone reservoirs offshore Qatar  

SciTech Connect

Following the discovery of non-structurally trapped oil accumulations in Cretaceous chalky reservoirs on the northern flank of the North Dome offshore QATAR, a seismic lateral prediction study was carried out for QATAR GENERAL PETROLEUM CORPORATION (Offshore Operations). The objectives of this study were to assist in the appraisal of these oil accumulations by predicting their possible lateral extent and to investigate if the technique applied could be used as a basis for further exploration of similar oil prospects in the area. Wireline logs of eight wells and some 1000 km of high quality seismic data were processed into acoustic impedance (A.I.) logs and seismic A.I. sections. Having obtained a satisfactory match of the A.I. well logs and the A.I. of the seismic traces at the well locations, relationships were established by the use of well log data which allowed the interpretation of the seismic A.I. in terms of reservoir quality. Measurements of the relevant A.I. characteristics were then carried out by computer along all seismic lines and porosity distribution maps prepared for some of the reservoirs. These maps, combined with detailed seismic depth contour maps at reservoir tops, lead to definition of good reservoir development areas downdip from poor reservoir quality zones i.e. of the stratigraphic trap areas, and drilling locations could thus be proposed. The system remains to be adequately calibrated when core material becomes available in the area of study.

Rubbens, I.B.H.M.; Murat, R.C.; Vankeulen, J.

1983-03-01

130

Stratigraphic and paleogeographical significance of Silurian acritarchs from Saudi Arabia  

Microsoft Academic Search

Abundant and well-preserved acritarchs of Early Silurian and late Middle to Late Silurian age have been obtained from marine subsurface sequences in seven exploratory wells drilled by the Saudi Arabian Oil Company in central and northwestern parts of Saudi Arabia. Preliminary results on their stratigraphic distribution allow an informal zonation of 9 regional acritarch assemblages zones to be proposed. Correlations

Alain Le Hérisse; Haytham Al-Tayyar; Hans van der Eem

1995-01-01

131

Stratigraphic nomenclature of late quaternary pyroclastic deposits in New Zealand  

Microsoft Academic Search

Stratigraphic nomenclature of unconsolidated pyroclastic deposits (tephra) should conform to the established procedures for other sedimentary rocks. Members should not be established before the formations of which they are part. The geographic part of new rock unit names should preferably not be that of a volcano, except in the case of deposits of historic eruptions. A formation or a member

D. R. Gregg

1961-01-01

132

Reassessment of offshore platforms  

SciTech Connect

Data from Hurricane Andrew demonstrated that the systems and procedures in place for evacuating offshore workers and minimizing oil spills and environmental damage functioned as planned. While the vast majority of the platforms survived the storm with no damage, a few of the older platforms (installed prior to 1972) either collapsed or suffered severe damage. The collapsed platforms were designed with insufficient deck height to clear the storm waves. In recent years, the API RP 2A has introduced guidance for minimum air gap, minimum structures, platform inspection and platform reuse. These provisions, coupled with natural attribution of the older platforms, will significantly improve the performance of platforms in the future. The reliability of NDT techniques to detect major structural defects should be improved through continued research. While flooded member detection is used by several operators as a screening tool to detect major defects underwater, its reliability is not always good and further research is needed in this area. Another area of high priority research is related to the use of Remotely Operated Vehicles (ROV) to perform underwater inspection of structures. 51 refs., 7 figs.

Nair, V.V.D.; Kuhn, J.M. (Mobil Research and Development Corporation, Dallas, TX (United States))

1993-05-01

133

Stratigraphic characterization of the Anthropocene: a progress report  

NASA Astrophysics Data System (ADS)

Rapid and large-scale anthropogenic changes have led to the concept that we are now living through the beginning of the Anthropocene Epoch - an interval of geological time dominated by human influence. The term was proposed little more than a decade ago by Paul Crutzen, the Nobel Prize-winning atmospheric chemist, and has since been widely used - and sharply debated. Its stratigraphic analysis needs considering the various kinds of historical and environmental change in terms of geological - or more precisely stratigraphic - change. Lithostratigraphic change, for instance, is strikingly represented by the spread of the 'urban stratum', the refashioning of sand, clay and limestone into our buildings, foundations and transport systems. Biostratigraphic changes include the ongoing mass extinction event and the effect of invasive species (while deep human-made bioturbation is a novel aspect the fossil record). Chemostratigraphic changes include the reshaping of the Earth's natural carbon, phosphorus and nitrogen cycles. As regards the potential formalizing of the Anthropocene, one question to be pursued relates to the chronostratigraphic definition of the phenomena involved: that is, given that many of these transformations are diachronous on human timescales, can an Anthropocene Series, with a synchronous time boundary, be characterized and mapped across the Earth's surface? Efforts to answer this question (Williams et al. 2011; Waters et al., in press) should help in the understanding of the Anthropocene within its geological context, and also in exploring the stratigraphic relation between time and rock generally at very fine stratigraphic timescales. Waters, C.W., Zalasiewicz, J.A., Williams, M., Ellis, M. & Snelling, A. In press. A Stratigraphical Basis for the Anthropocene. Geological Society of London, Special Publication. Williams, M., Zalasiewicz, J., Haywood, A. & Ellis M. (eds) 2011. The Anthropocene: a new epoch of geological time? Philosophical Transactions of the Royal Society 369A, 833-1112.

Zalasiewicz, Jan

2014-05-01

134

Application of nonmarine genetic sequence stratigraphic concepts to reservoir characterization in the fluvial-lacustrine Westbourne Formation, Eromanga basin, Australia  

SciTech Connect

A high-resolution sequence stratigraphic analysis of the Westbourne Formation identified five chronostratigraphic genetic units each separated by thin, but laterally extensive, shale markers interpreted as maximum lacustrine flooding surfaces. The flooding surfaces were primarily identified by their lateral persistence and high gamma-ray log response, but marked changes in bedding architecture across these surfaces also facilitated their identification. The changes in bedding architecture reflect reorganization of the depositional systems from one depositional episode to the next. The Westbourne Formation is interpreted as a series of fluvially-dominated lacustrine delta sequences. Although the genetic units generally display lobate to digitate sand body geometries, sediment transport directions between successive units is highly variable. The complex morphology of the distributary network and accompanying high degree of facies variability indicates shallow lacustrine sedimentation similar to that in the modern inland Niger River delta which provides a modern analog. Westbourne fluid flow trends were established by mapping water encroachment during field development, observing differential depletion in repeat formation test data, and monitoring production response to water shut-off workovers. The fluid flow trends emphasized the highly layered character of the Westbourne reservoirs and integrating these trends with the geologic architecture defined stratigraphic controls on Westbourne flow units. The stratigraphic framework proved essential for unraveling sediment transport patterns and thus, predicting reservoir sandstone distribution. The stratigraphic framework also provided the key to understanding water encroachment and pressure a depletion which, when combined with predicted sandstone geometries, identified several step-out drilling and recompletion opportunities.

Hamilton, D.S.; Holtz, M.H.; Yeh, J. (Univ. of Texas, Austin, TX (United States)) (and others)

1996-01-01

135

Biothems: Sequence stratigraphic units and their implications for regional tectono-stratigraphic interpretations  

SciTech Connect

Biothems are regional wedge- or lens-shaped bodies of strata that are bounded shelfward or cratonward by paleontologically recognizable unconformities; generally thicken on marine shelves, where they are typically conformable with underlying and overlying biothems; are commonly thinner or represent starved sequences further basinward; and in their most basinward extent, are either bounded by biostratigraphically recognizable unconformities or are conformable with underlying and overlying biothems. As recognized to date, biothems have a logical distribution of faunal and floral components, as well as facies groupings that represent internally consistent and logical sequences of depositional environments. A west-to-east transect within the North American Mississippian System which extends from the Basin and Range Province, across the Transcontinental Arch (TA), into the Anadarko Basin, was constructed to demonstrate the regional distribution and tectono-stratigraphic significance of biothems relative to the axis of the TA. The relationships portrayed on the transect, tied to an understanding of North American Mississippian paleogeography, imply that biothems deposited during relative highstand events on one flank of the TA are time-equivalent to biothems deposited during relative lowstand events on the opposite flank of the TA. This distribution is interpreted to have been controlled by intraplate tectonic events that formed piano key basins along the flanks of the TA. The spatial patterns of these basins are not consistent with published models of basin evolution. A further conclusion is that the lack of coincident, transgressive or regressive Mississippian biothems on either flank of the TA suggests that it is inadvisable to impose the Mississippi Valley-derived eustasy curve on western flank depositional sequences.

Lane, H.R. (Amoco Production Co., Houston, TX (United States)); Frye, M.W. (Mitre Corp., San Antonio, TX (United States)); Couples, G.D. (Univ. of Glasgow (United Kingdom))

1992-01-01

136

Offshore Wind Energy Market Overview (Presentation)  

SciTech Connect

This presentation describes the current international market conditions regarding offshore wind, including the breakdown of installation costs, how to reduce costs, and the physical siting considerations considered when planning offshore wind construction. The presentation offers several examples of international existing and planned offshore wind farm sites and compares existing international offshore resources with U.S. resources. The presentation covers future offshore wind trends and cites some challenges that the United States must overcome before it will be able to fully develop offshore wind sites.

Baring-Gould, I.

2013-07-01

137

76 FR 24504 - National Offshore Safety Advisory Committee  

Federal Register 2010, 2011, 2012, 2013, 2014

...National Offshore Safety Advisory Committee...National Offshore Safety Advisory Committee...Wyndham Riverfront Hotel, Bacchus room...Department of Homeland Security'' and the docket...National Offshore Safety Advisory Committee...and gas offshore industry. Agenda The...

2011-05-02

138

Challenges and Opportunities in Geomorphic-Stratigraphic Linkages  

NASA Astrophysics Data System (ADS)

Whereas geomorphic processes undeniably modulate the depositional sequences that constitute the stratigraphic record, a discrete geomorphic imprint is commonly difficult to discern in ancient sediments. Part of this disconnect results from the characteristics of typical study sites. Many geomorphic studies are conducted in terrain, i.e., mountains, that is degrading via long-term erosion, such that (i) the preservation potential of the geomorphic-depositional record is negligible and (ii) the geomorphic processes may be distinctly different from those in depositional basins. Both the disparate time scales of observation and the differing preservation tendencies of sedimentologic events in the geomorphic versus stratigraphic record also inhibit development of unambiguous linkages between them. Even some spectacularly clear stratigraphic records of deformation, such as those evinced by growth strata, may be very subtle in a modern geomorphic setting as they are being formed. To the extent that large-scale, "catastrophic" geomorphic events significantly influence the stratigraphic record, the infrequency of such events dictates that relevant geomorphic observations of them are commonly sparse. Despite these difficulties, improved understanding of geomorphic-stratigraphic connections are emerging from several perspectives. Geomorphic studies at the surface of actively aggrading basins provide modern depositional analogues. The ever-growing imagery archive available via Google Earth permits increasingly detailed reconstructions of the evolution of geomorphic and depositional systems in sites of ongoing sediment preservation in actively subsiding basins. Repeat LiDAR imaging provides quantification of channel geometries, incision, and deposition at time scales ranging from single events to decadal scales. Analogue models in which subsidence, base level, discharge, sediment supply can be controlled provide insights on the interplay between variables that modulates depositional patterns. In modern sites with high preservation potential, knowledge of the commonly changing geomorphic mosaic of local erosion and aggradation through space and time is key to reliable interpretations of the ancient record of depositional and erosional events, changing environmental conditions, and unconformities and sequence boundaries that together make up the temporally incomplete, composite stratigraphic sections that typify the sedimentary record.

Burbank, D. W.

2012-12-01

139

Foam pigs solve pipe cleaning problems offshore Brazil  

SciTech Connect

Pipeline systems in which conventional pigs cannot be run are common in such complex offshore installations as are found in Brazil`s Campos basin. These systems may contain changing pipe diameters or wet christmas trees and manifolds. A new concept for using low cost, low-density foam pigs for both liquid removal in wet-gas pipelines and paraffin removal in oil and multiphase pipelines has been successfully tested offshore Brazil. Although the present discussion focuses on condensate and paraffin removal in pipelines, the principles can be applied to several kinds of operations including general pipeline cleaning, product removal or separation in pipeline, corrosion evaluation, and chemical product application.

Lima, P.C.R.; Neto, S.J.A. [Petroleo Brasileiro S.A., Rio de Janeiro (Brazil)

1995-10-02

140

Prediction of Weather Operating Windows for Offshore Drilling Vessels  

Microsoft Academic Search

A management 'tool' for predicting Weather Operating Windows for offshore drilling operations has been developed and tested for the dynamic positioning drillship PETREL. It is shown that two measures are required in making such an assessment: the persistence of vessel heave response as it affects drilling operations and the probable downtimes with respect to each drilling operation throughout the year

J. G. Hayes; M. S. Hirt; D. G. McGillivray; Bill Nicholls; Robert Waymouth; Boris Weisman

1983-01-01

141

Proceedings of the 22nd annual offshore technology conference  

SciTech Connect

This book contains the proceedings of the 22nd annual offshore technology conference, volume 4. Topics covered include: axial load capacity of steel piles in sand; hydrodynamic aspects of flexible riser; a deepwater test of subsea wirelining techniques; and soil reaction to axially loaded piles.

Not Available

1990-01-01

142

Coupled dynamic analysis of floating offshore wind farms  

E-print Network

dynamic analysis of an offshore floating wind turbine system including blade-rotor dynamics and platform motions. As a test case, the TLP-type floater system with 3 blades of 70-m diameter designed by the National Renewable Energy Laboratory (NREL...

Shim, Sangyun

2009-05-15

143

Sedimentology and stratigraphic development of the upper Nyalau Formation (Early Miocene), Sarawak, Malaysia: A mixed wave- and tide-influenced coastal system  

NASA Astrophysics Data System (ADS)

This work presents the first detailed facies analysis of the upper Nyalau Formation exposed around Bintulu, Sarawak, Malaysia. The Lower Miocene Nyalau Formation exposures in NW Sarawak represent one of the closest sedimentological outcrop analogues to the age equivalent, hydrocarbon-bearing, offshore deposits of the Balingian Province. Nine types of facies associations are recognised in the Nyalau Formation, which form elements of larger-scale facies successions. Wave-dominated shoreface facies successions display coarsening upward trends from Offshore, into Lower Shoreface and Upper Shoreface Facies Associations. Fluvio-tidal channel facies successions consist of multi-storey stacks of Fluvial-Dominated, Tide-Influenced and Tide-Dominated Channel Facies Associations interbedded with minor Bay and Mangrove Facies Associations. Estuarine bay facies successions are composed of Tidal Bar and Bay Facies Associations with minor Mangrove Facies Associations. Tide-dominated delta facies successions coarsen upward from an Offshore into the Tidal Bar Facies Association. The Nyalau Formation is interpreted as a mixed wave- and tide-influenced coastal depositional system, with an offshore wave-dominated barrier shoreface being incised by laterally migrating tidal channels and offshore migrating tidal bars. Stratigraphic successions in the Nyalau Formation form repetitive high frequency, regressive-transgressive cycles bounded by flooding surfaces, consisting of a basal coarsening upward, wave-dominated shoreface facies succession (representing a prograding barrier shoreface and/or beach-strandplain) which is sharply overlain by fluvio-tidal channel, estuarine bay or tide-dominated delta facies successions (representing more inshore, tide-influenced coastal depositional environments). An erosion surface separates the underlying wave-dominated facies succession from overlying tidal facies successions in each regressive-transgressive cycle. These erosion surfaces are interpreted as unconformities formed when base level fall resulted in deep incision of barrier shorefaces. Inshore, fluvio-tidal successions above the unconformity display upward increase in marine influence and are interpreted as transgressive incised valley fills.

Amir Hassan, Meor H.; Johnson, Howard D.; Allison, Peter A.; Abdullah, Wan Hasiah

2013-10-01

144

The Offshore Services Global Value Chain  

E-print Network

The Offshore Services Global Value Chain ECONOMIC UPGRADING AND WORKFORCE DEVELOPMENT Karina & COMPETITIVENESS #12;The Offshore Services Global Value Chain: Economic Upgrading and Workforce Development "Skills for Upgrading: Workforce Development and Global Value Chains in Developing Countries" This research project

Richardson, David

145

Offshore Aquaculture in the United States  

E-print Network

Offshore Aquaculture in the United States: Economic Considerations, Implications & Opportunities from: http://aquaculture.noaa.gov This document should be cited as follows: Rubino, Michael (editor). 2008. Offshore Aquaculture in the United States: Economic Considerations, Implications & Opportunities

146

Probabilistic stratigraphic alignment of Pleistocene d18O records  

NASA Astrophysics Data System (ADS)

Stratigraphic alignment is the primary way in which long marine climate records are placed on a common age model. We present a probabilistic pairwise alignment algorithm based on Hidden Markov models (HMM) to estimate alignment uncertainty and apply it to the alignment of Pleistocene benthic d18O records. This probabilistic algorithm improves upon the dynamic programming algorithm of Lisiecki and Lisiecki (2002) in the following ways: Maximum likelihood (MLE) or maximum a-posteriori parameter (MAP) estimation generates automatic parameter estimates directly from that data of the two input stratigraphic sequences; samples of alignments drawn directly and independently from posterior distributions along with probabilities of each sampled alignment; ensemble-based point estimates of alignments [Carvalho & Lawrence, 2008]; confidence limits on alignment parameter estimates; probabilities of all components of the alignments including marginal probabilities of the alignment of each pair of points within the two records and differences in sedimentation rates; and overall measures of alignment reliability using Bayesian confidence limits.

Lawrence, C. E.; Lin, L.; Stern, J.; Lisiecki, L. E.

2011-12-01

147

Stratigraphic architectures spotted in southern Melas Chasma, Valles Marineris, Mars  

NASA Astrophysics Data System (ADS)

The distribution in space and time of liquid water on Mars is relevant to astrobiology and astroclimatology. To date, most orbital observations that attest to past fluvial and lacustrine activity on Mars have been dedicated to surficial landforms (i.e., drainage networks and depositional fans). Here we report an unprecedented identification of typical stratigraphic architectures made in Mars Global Surveyor Mars Orbiter Camera images of layered material in southern Melas Chasma. A particular set of strata is arranged in three depositional sequences bounded by stratigraphic unconformities. The sequences show spectacular steeply inclined clinoforms, and a broad channel-like depression. There are the same complex stratal patterns in Valles Marineris on Mars as there are in terrestrial deposits. Insights into these three-dimensional deposit geometries are used to tentatively isolate specific depositional processes and point to ancient subaqueous settings. Findings in southern Melas indicate a very attractive spot to which the search for ancient habitable environments on Mars could be directed.

Dromart, Gilles; Quantin, Cathy; Broucke, Olivier

2007-04-01

148

Offshore wind farm layout optimization  

NASA Astrophysics Data System (ADS)

Offshore wind energy technology is maturing in Europe and is poised to make a significant contribution to the U.S. energy production portfolio. Building on the knowledge the wind industry has gained to date, this dissertation investigates the influences of different site conditions on offshore wind farm micrositing---the layout of individual turbines within the boundaries of a wind farm. For offshore wind farms, these conditions include, among others, the wind and wave climates, water depths, and soil conditions at the site. An analysis tool has been developed that is capable of estimating the cost of energy (COE) from offshore wind farms. For this analysis, the COE has been divided into several modeled components: major costs (e.g. turbines, electrical interconnection, maintenance, etc.), energy production, and energy losses. By treating these component models as functions of site-dependent parameters, the analysis tool can investigate the influence of these parameters on the COE. Some parameters result in simultaneous increases of both energy and cost. In these cases, the analysis tool was used to determine the value of the parameter that yielded the lowest COE and, thus, the best balance of cost and energy. The models have been validated and generally compare favorably with existing offshore wind farm data. The analysis technique was then paired with optimization algorithms to form a tool with which to design offshore wind farm layouts for which the COE was minimized. Greedy heuristic and genetic optimization algorithms have been tuned and implemented. The use of these two algorithms in series has been shown to produce the best, most consistent solutions. The influences of site conditions on the COE have been studied further by applying the analysis and optimization tools to the initial design of a small offshore wind farm near the town of Hull, Massachusetts. The results of an initial full-site analysis and optimization were used to constrain the boundaries of the farm. A more thorough optimization highlighted the features of the area that would result in a minimized COE. The results showed reasonable layout designs and COE estimates that are consistent with existing offshore wind farms.

Elkinton, Christopher Neil

149

Paleomagnetic constrains in the reconstruction of the recent stratigraphic evolution of the Po delta  

NASA Astrophysics Data System (ADS)

The delta and prodelta deposits are characterized by a complex stratigraphic architecture that can be approached with several multidisciplinary tools. We present an example from the Po delta system characterized by alternating phases of rapid advance and abandonment of its multiple deltaic lobes that has been investigated through: (1) a review of historical cartography extending back several centuries; (2) integrated surveys of VHR seismic profiles recorded offshore of the modern delta from water depths as shallow as 5 m to the toe of the prodelta in about 30 m; and (3) sedimentological and geochronological data from precisely positioned sediment cores. Within this well known stratigraphic framework we have acquired seismic data and sediment cores in the area of the post roman Po delta system. However a precise dating of the recent evolution of depositional delta lobes is difficult because of the lack of suitable dating methods. To constrain the emplacement timing of the Renaissance lobes a paleomagnetic studies was carried out on a sedimentary sequence representing a seismic facies well correlated in the cores by whole core magnetic susceptibility profile. Forty eight samples were collected from a core section (RER96-1) characterized by a fine grained lithology suitable for paleomagnetic investigations. The characteristic remanent magnetization (ChRM) of the sediments has been obtained by applying an AF cleaning between 10 and 30 millitesla. The results have been compared with the directions recorded by the historical lavas of the Etna and Vesuvius. The combination of the trends observed in the declination and inclination suggests that the results can be compatible with the directions of the secular variation of the earth magnetic field occurring during the XVII century. This allow to date the sismic unit as representative of the beginning of the new delta following the Porto Viro avulsion made by the Venice Republic in 1604 AD. This delta history reflects the forcing of high-frequency climate change, autocyclic avulsions, and anthropogenic factors, acting on variable, but typically short, time scales. By using multidisciplinary methods of investigation is possible to detect the sedimentary response forced by anthropic impact at centennial/decadal time scale.

Correggiari, Annamaria; Vigliotti, Luigi; Remia, Alessandro; Perini, Luisa; Calabrese, Lorenzo; Luciani, Paolo

2014-05-01

150

New structural and stratigraphic interpretation of Lake Superior basin from hydrocarbon exploration geophysics and geology  

SciTech Connect

Between October 1987 and April 1992, two deep boreholes were drilled along the south shore of Lake Superior in a test of the hydrocarbon potential of the conglomerate, sandstone and shale composing the Middle Proterozoic Oronto Group ({approximately}1 billion years). These drilling ventures, preceded by geophysical programs, and combined with wireline and core information, support new interpretations of the structural and stratigraphic geology associated with the Midcontinent Rift System in the Lake Superior district. No.7-22 Terra-Patrick: A stratigraphic, but not structural fit. This borehole in Bayfield County, Wisconsin, drilled an expected sequence of Oronto Group clastic redbeds. No viable hydrocarbon shows were encountered. Six second reflection seismology profiles collected in northwestern Wisconsin indicate the Douglas Fault decreases in throw in an easterly direction, changing to a fold northeast of the borehole. This termination is associated with the south flank of White`s Ridge, a pre-rift residual high identified through modeling studies and seismic interpretations by local absence of Midcontinent Rift volcanics and overlying strata. To the southwest of Isle Royale, the pre-rift Grand Marias Ridge exhibits similar characteristics. No.1-29 St. Amour: A structural, but not stratigraphic, fit. Drilled in Alger County, Michigan, the St. Amour well appears to bottom in pre-rift metamorphic basement rocks. This hole was 100% cored. No hydrocarbon shows were reported. Reflection seismology profile analyses verify a change in strike, from northeast to southeast, of the Keweenaw Fault in the eastern Lake Superior Basin. The drilled section included 6,000 feet of pre-Paleozoic red-beds containing cross-bedding, ripple marks, and multiple fining-upward strata.

Dickas, A.B. [Univ. of Wisconsin, Superior, WI (United States)

1996-09-01

151

Offshore Drilling With Preformed Stable Foam  

Microsoft Academic Search

Preformed stable foam has proven successful in drilling many onshore underpressured or fluidsensitive formations, however, its use in offshore applications to date has been limited. Recently two redrills were completed offshore in the Santa Barbara Channel with stable foam. Because the operation was performed offshore, it offered new challenges. 1. The use of foam in conjunction with a downhole mud

D. L. Hall; R. D. Roberts

1984-01-01

152

Mobile robots for offshore inspection and manipulation  

Microsoft Academic Search

This paper analyzes the potential to apply mobile service robots in offshore oil and gas producing environments. The required hardware and software components and abilities of such a mobile offshore inspection and manipulation robot are presented in this paper. Possible applications of mobile service robots in an offshore environment range from simple visual inspection tasks to physical intervention with the

Matthias Bengel; Kai Pfeiffer; Birgit Graf; Alexander Bubeck; Alexander Verl

2009-01-01

153

Offshore Wind Turbines: Some Technical Challenges  

E-print Network

1 Offshore Wind Turbines: Some Technical Challenges Prof. Guy Houlsby FREng Oxford University House engineers concerned with installation of offshore wind turbines. The author is Professor of Civil issues · An example: ­ DTI project on foundations for offshore turbines · Conclusions The talk will begin

Houlsby, Guy T.

154

Gas Production From a Cold, Stratigraphically Bounded Hydrate Deposit at the Mount Elbert Site, North Slope, Alaska  

Microsoft Academic Search

As part of an effort to identify suitable targets for a planned long-term field test, we investigate by means of numerical simulation the gas production potential from unit D, a stratigraphically bounded (Class 3) permafrost-associated hydrate occurrence penetrated in the ount Elbert well on North Slope, Alaska. This shallow, low-pressure deposit has high porosities, high intrinsic permeabilities and high hydrate

G. J. Moridis; S. Silpngarmlert; M. T. Reagan; T. S. Collett; K. Zhang

2009-01-01

155

Antarctic Drilling Recovers Stratigraphic Records From the Continental Margin  

NASA Astrophysics Data System (ADS)

The Antarctic Geological Drilling (ANDRILL) program—a collaboration between Germany, Italy, New Zealand, and the United States that is one of the larger programs endorsed by the International Polar Year (IPY; http://www.ipy.org)-successfully completed the drilling phase of the Southern McMurdo Sound (SMS) Project in December 2007. This second drill core of the program's campaign in the western Ross Sea, Antarctica, complements the results of the first drilling season [Naish et al., 2007] by penetrating deeper into the stratigraphic section in the Victoria Land Basin and extending the recovered time interval back to approximately 20 million years ago. The primary objectives of ANDRILL (http://www.andrill.org/) were to recover stratigraphic records from the Antarctic continental margin that document key steps in Antarctica’s Cenozoic (0- to 65-million-year-old) climatic and glacial history, and in the tectonic evolution of the Transantarctic Mountains and the West Antarctic Rift System [Harwood et al., 2006]. These two ANDRILL stratigraphic drill cores are guiding the understanding of the speed, size, and frequency of the past 20 million years of glacial and interglacial changes in the Antarctic region. The drill cores will help to establish, through their correlation to existing records and their integration with climate and ice sheet models, how these local changes relate to regional and global events.

Harwood, David; Florindo, Fabio; Talarico, Franco; Levy, Richard; Kuhn, Gerhard; Naish, Tim; Niessen, Frank; Powell, Ross; Pyne, Alex; Wilson, Gary

2009-03-01

156

Geologic evolution and sequence stratigraphy of the offshore Pelotas Basin, southeast Brazil  

SciTech Connect

The Brazilian marginal basins have been studied since the beginning of the 70s. At least nine large basins are distributed along the entire Eastern continental margin. The sedimentary infill of these basins consists of lower Cretaceous (continental/lacustrine) rift section underlying marine upper Cretaceous (carbonate platforms) and marine upper Cretaceous/Tertiary sections, corresponding to the drift phase. The sedimentary deposits are a direct result of the Jurassic to lower Cretaceous break-up of the Pangea. This study will focus on the geologic evolution and sequence stratigraphic analysis of the Pelotas basin (offshore), located in the Southeast portion of the Brazilian continental margin between 28{degrees} and 34{degrees} S, covering approximately 50,000 Km{sup 2}. During the early Cretaceous, when the break-up of the continent began in the south, thick basaltic layers were deposited in the Pelotas basin. These basalts form a thick and broad wedge of dipping seaward reflections interpreted as a transitional crust. During Albian to Turonian times, due to thermal subsidence, an extensive clastic/carbonate platform was developed, in an early drift stage. The sedimentation from the upper Cretaceous to Tertiary was characterized by a predominance of siliciclastics in the southeast margin, marking an accentuate deepening of the basin, showing several cycles related to eustatic fluctuations. Studies have addressed the problems of hydrocarbon exploration in deep water setting within a sequence stratigraphic framework. Thus Pelotas basin can provide a useful analogue for exploration efforts worldwide in offshore passive margins.

Abreu, V.S. [Petrobras and Rice Univ., Houston, TX (United States)

1996-12-31

157

Geologic evolution and sequence stratigraphy of the offshore Pelotas Basin, southeast Brazil  

SciTech Connect

The Brazilian marginal basins have been studied since the beginning of the 70s. At least nine large basins are distributed along the entire Eastern continental margin. The sedimentary infill of these basins consists of lower Cretaceous (continental/lacustrine) rift section underlying marine upper Cretaceous (carbonate platforms) and marine upper Cretaceous/Tertiary sections, corresponding to the drift phase. The sedimentary deposits are a direct result of the Jurassic to lower Cretaceous break-up of the Pangea. This study will focus on the geologic evolution and sequence stratigraphic analysis of the Pelotas basin (offshore), located in the Southeast portion of the Brazilian continental margin between 28[degrees] and 34[degrees] S, covering approximately 50,000 Km[sup 2]. During the early Cretaceous, when the break-up of the continent began in the south, thick basaltic layers were deposited in the Pelotas basin. These basalts form a thick and broad wedge of dipping seaward reflections interpreted as a transitional crust. During Albian to Turonian times, due to thermal subsidence, an extensive clastic/carbonate platform was developed, in an early drift stage. The sedimentation from the upper Cretaceous to Tertiary was characterized by a predominance of siliciclastics in the southeast margin, marking an accentuate deepening of the basin, showing several cycles related to eustatic fluctuations. Studies have addressed the problems of hydrocarbon exploration in deep water setting within a sequence stratigraphic framework. Thus Pelotas basin can provide a useful analogue for exploration efforts worldwide in offshore passive margins.

Abreu, V.S. (Petrobras and Rice Univ., Houston, TX (United States))

1996-01-01

158

Electrokinetic improvement of offshore foundations  

Microsoft Academic Search

Offshore and near-shore structures for energy exploration and production, harbour work and other facilities are often situated on very soft marine clay deposits that have shear strengths of a few kilopascals. The design of foundations embedded in these soft deposits often poses a challenge for geotechnical engineers, i.e., to satisfy the bearing capacity requirement, while at the same time minimizing

Silvana Micic

2003-01-01

159

Towers for Offshore Wind Turbines  

Microsoft Academic Search

Increasing energy demand coupled with pollution free production of energy has found a viable solution in wind energy. Land based windmills have been utilized for power generation for more than two thousand years. In modern times wind generated power has become popular in many countries. Offshore wind turbines are being used in a number of countries to tap the energy

V. J. Kurian; S. P. Narayanan; C. Ganapathy

2010-01-01

160

National Offshore Wind Energy Grid Interconnection Study  

SciTech Connect

The National Offshore Wind Energy Grid Interconnection Study (NOWEGIS) considers the availability and potential impacts of interconnecting large amounts of offshore wind energy into the transmission system of the lower 48 contiguous United States. A total of 54GW of offshore wind was assumed to be the target for the analyses conducted. A variety of issues are considered including: the anticipated staging of offshore wind; the offshore wind resource availability; offshore wind energy power production profiles; offshore wind variability; present and potential technologies for collection and delivery of offshore wind energy to the onshore grid; potential impacts to existing utility systems most likely to receive large amounts of offshore wind; and regulatory influences on offshore wind development. The technologies considered the reliability of various high-voltage ac (HVAC) and high-voltage dc (HVDC) technology options and configurations. The utility system impacts of GW-scale integration of offshore wind are considered from an operational steady-state perspective and from a regional and national production cost perspective.

Daniel, John P. [ABB Inc; Liu, Shu [ABB Inc; Ibanez, Eduardo [National Renewable Energy Laboratory; Pennock, Ken [AWS Truepower; Reed, Greg [University of Pittsburgh; Hanes, Spencer [Duke Energy

2014-07-30

161

Offshore Renewable Energy R&D (Fact Sheet)  

SciTech Connect

This fact sheet describes the offshore renewable energy R&D efforts at NREL's NWTC. As the United States increases its efforts to tap the domestic energy sources needed to diversify its energy portfolio and secure its energy supply, more attention is being focused on the rich renewable resources located offshore. Offshore renewable energy sources include offshore wind, waves, tidal currents, ocean and river currents, and ocean thermal gradients. According to a report published by the National Renewable Energy Laboratory (NREL) in 2010,1 U.S. offshore wind resources have a gross potential generating capacity four times greater than the nation's present electric capacity, and the Electric Power Research Institute estimates that the nation's ocean energy resources could ultimately supply at least 10% of its electric supply. For more than 30 years, NREL has advanced the science of renewable energy while building the capabilities to guide rapid deployment of commercial applications. Since 1993, NREL's National Wind Technology Center (NWTC) has been the nation's premier wind energy research facility, specializing in the advancement of wind technologies that range in size from a kilowatt to several megawatts. For more than 8 years, the NWTC has been an international leader in the field of offshore floating wind system analysis. Today, researchers at the NWTC are taking their decades of experience and extensive capabilities and applying them to help industry develop cost-effective hydrokinetic systems that convert the kinetic energy in water to provide power for our nation's heavily populated coastal regions. The center's capabilities and experience cover a wide spectrum of wind and water energy engineering disciplines, including atmospheric and ocean fluid mechanics, aerodynamics; aeroacoustics, hydrodynamics, structural dynamics, control systems, electrical systems, and testing.

Not Available

2011-10-01

162

Seismic, structural, tectonic and stratigraphic characterization of Cretaceous sequences within the Orphan Basin, offshore Newfoundland and Labrador  

Microsoft Academic Search

2 . It is bounded in the west by the Bonavista Platform, in the south by high blocks separating it from the Jeanne d'Arc and Flemish Pass basins, in the north by the onlap of sediments and the Charlie Gibbs Fracture Zone, and in the east by a high basement ridge running between the Orphan Knoll and the Flemish Cap.

Victoria E. Hardy; Michael Enachescu; Jim Wright

163

Stratigraphic and structural analysis of the Neogene sediments of the offshore portion of the Salina del Istmo Basin, southeastern Mexico  

Microsoft Academic Search

Southeastern Mexico has been affected by regional and local tectonic events. Regional tectonic events are the Gulf of Mexico opening and the lateral movement of micro-plates on the Pacific margin. The local tectonic events are related to salt tectonics. Autochthonous Jurassic salt serves as the detachment level for the main compressional event in the late Miocene. Jurassic salt was allochthonously

Pedro Tomas Gomez-Cabrera

2003-01-01

164

Reservoir anatomy within a sequence stratigraphic framework: The Pennsylvanian Breathitt group of Eastern Kentucky  

SciTech Connect

Detailed quantitative sequence stratigraphic analysis and three-dimensional (3-D) modeling of the fluvio-deltaic Pikeville, Hyden, and four Corners formations of the Breathitt Group, eastern Kentucky, indicate that it is possible to make confident deterministic correlations of sand bodies at offshore development well spacings. The key to high-confidence correlation is the delineation of the 3-D architecture of third-order composite sequences, which are seismically mappable, and the recognition of internal fourth-order sequences, which are stacked into lowstand, transgressive, and highstand sequence sets. Volumetric partitioning of reservoir sand bodies between systems tracts and sequences allows prediction of channel sandstone geometries and channel: crevasse splay ratios. Furthermore, channel-fill type is predictable from the sequence stratigraphy. Within 13 studied fourth-order sequences, incised valley fills represent the main reservoirs, which are laterally continuous over tens of kilometers. Sand bodies within transgressive and early highstand systems tracts are usually filled by siltstones or heteroliths and have geometries less than 1.0 km in width. Within fourth-order sequence sets, incised valley fills are sometimes vertically stacked to produce anaomalously thick fluvial sand bodies. These are the prime potential producing zones within coastal plain reservoirs. High-resolution sequence stratigraphy thus provides a deterministic approach to correlation and 3-D modeling. Use of the Stratamodel geocellular modeling system permits circulation of connectivities for different systems tracts and sequence sets, thus allowing the development of conceptual models for perforation policy in complex [open quotes]jigsaw-type[close quotes] reservoirs.

Aitken, J.F.; Flint, S.S. (Univ. of Liverpool (United Kingdom))

1993-09-01

165

Japan Completes First Offshore Production Test .............................1  

E-print Network

included drilling a production well and two monitoring wells, acquiring extensive downhole data including..........................................23 Announcements ...................... 27 · North Slope Oil and Gas Lands Set Aside for Methane Research Conference on Gas Hydrate Systems · New Book on Hydrate Resources in the Deepwater Arctic Ocean

166

Ultrasonic thickness testing of aging offshore structures  

E-print Network

Thickness Bounds from Reduced Samples, Member 03 (Rings 1-7) . . . . . . . . 108 Thickness Bounds from Reduced Samples, Member 03 (Rings 8-16) . . . . . . 109 4. 17 4. 18 4. 19 Thickness Bounds from Reduced Samples, Member 04. . . . Thickness Bounds... . . . 70 4. 13 Longitudinal Relationships for Member 03 (Average Over All Rays). . . . . . 71 4. 14 4. 15 4. 16 4. 17 4. 18 Longitudinal Relationships for Member 03 (Rings 1-7). . . . Longitudinal Relationships (Average Over AII Rays), Member 03...

Ellison, Brian Kirk

1999-01-01

167

Offshore hydrodynamics. [Engineering design and research needs for offshore facilities  

SciTech Connect

In this paper, the author presents several applied as well as fundamental research problems related to the future needs of the offshore engineering. The paper starts out with a detailed discussion of the current uncertainties and constraints. Then, specific research issues on environmental input conditions, on the role of computational fluid dynamics, and on damping and dynamic response are presented. It is suggested that an appreciation of the input parameters, acquisition of extensive data to properly characterize the ocean environment, development of new methods and tools to acquire relevant data, extensive use of the computational methods, basic/applied research on the dynamic response and damping of structures, use of new materials, science-and-technology transfer from sister disciplines (e.g., aerospace industry, keeping in mind the complexities brought about by the presence of the air-water interface), and other related research will significantly enhance ones ability to design and build a variety of safer and economical offshore structures in deeper waters as well as over marginal fields in the next few decades. This herculean effort will require several decades of complementary experimental, numerical and analytical studies of ocean-structure interaction which will serve to elucidate the basic as well as applied fluid mechanics phenomena relevant to the offshore mechanics.

Sarpkaya, T. (Naval Postgraduate School, Monterrey, CA (United States). Dept. of Mechanical Engineering)

1993-02-01

168

Stratigraphic and structural interpretation with 3-D seismic coherence  

SciTech Connect

3-D seismic discontinuity is useful for identifying faults, stratigraphic features and the relationship between them. This paper covers the application of coherence technology to three basins; the Gulf of Mexico, the North Sea, and the Ardmore Basin of Oklahoma. In the Gulf of Mexico, 3-D coherence data may be used to simultaneously view faults and stratigraphic features and therefore see the relationship between them. Coherence data reveal channels that avoid a structural high generated by a salt dome, channels that change direction as they cross faults, radial faults adjacent to a salt dome, and complex and en-echelon faults. Since the coherence process is applied to non-interpreted seismic data, these features are available for viewing without the time or bias of interpretation. Coherence time slices from the Ardmore Basin of Oklahoma were compared with a horizon-dip map and a discrepancy in the fault patterns was noted. Further analysis revealed that subtle errors in the autopicking had created a false bend in a fault trace seen on the horizon-dip map. After correction, the horizon-dip map and coherence time slice indicated similar fault patterns. Since the coherence method is run on the raw seismic data, it provides a view of the faults that is not biased by the interpreter or horizon autopicker. In the North Sea, faults may exhibit meandering patterns that are easy to interpret on traditional time-slices where they cut perpendicular to stratigraphic bedding but are difficult to recognize where they cut parallel to bedding. The coherence technique images faults in any orientation equally well.

Bahorich, M.; Lopez, J.; Haskell, N.; Nissen, S.; Poole, A. [Amoco Corp., Denver, CO (United States)

1996-06-01

169

Stratigraphic and structural interpretation with 3-D seismic coherence  

SciTech Connect

3-D seismic discontinuity is useful for identifying faults, stratigraphic features and the relationship between them. This paper covers the application of coherence technology to three basins; the Gulf of Mexico, the North Sea, aid the Ardmore Basin of Oklahoma. In the Gulf of Mexico, 3-D coherence data may be used to simultaneously view faults and stratigraphic features and therefore see the relationship between them. Coherence data reveal channels that avoid a structural high generated by a salt dome, Channels that change direction as they cross faults, radial faults adjacent to a salt dome, and complex and en-echelon faults. Since the coherence process is applied to non- interpreted seismic data, these features are available for viewing without the time or bias of interpretation. Coherence time slices from the Ardmore Basin of Oklahoma were compared with a horizon-dip map and a discrepancy in the fault patterns was noted. Further analysis revealed that subtle errors in the autopicking had created a false bend in a fault trace seen on the horizon-dip map. After correction, the horizon-dip map and coherence time slice indicated similar fault patterns. Since the coherence method is run on the raw seismic data, it provides a view of the faults that is not biased by the interpreter or horizon autopicker. In the North Sea, faults may exhibit meandering patterns that are easy to interpret on traditional time-slices where they cut perpendicular to stratigraphic bedding but are difficult to recognize where they cut parallel to bedding. The coherence technique images faults in any orientation equally well.

Bahorich, M.; Lopez, J.; Haskell, N. [Amoco Corp., Denver, CO (United States)] [and others

1996-12-31

170

Fossil preservation and the stratigraphic ranges of taxa  

NASA Technical Reports Server (NTRS)

The incompleteness of the fossil record hinders the inference of evolutionary rates and patterns. Here, we derive relationships among true taxonomic durations, preservation probability, and observed taxonomic ranges. We use these relationships to estimate original distributions of taxonomic durations, preservation probability, and completeness (proportion of taxa preserved), given only the observed ranges. No data on occurrences within the ranges of taxa are required. When preservation is random and the original distribution of durations is exponential, the inference of durations, preservability, and completeness is exact. However, reasonable approximations are possible given non-exponential duration distributions and temporal and taxonomic variation in preservability. Thus, the approaches we describe have great potential in studies of taphonomy, evolutionary rates and patterns, and genealogy. Analyses of Upper Cambrian-Lower Ordovician trilobite species, Paleozoic crinoid genera, Jurassic bivalve species, and Cenozoic mammal species yield the following results: (1) The preservation probability inferred from stratigraphic ranges alone agrees with that inferred from the analysis of stratigraphic gaps when data on the latter are available. (2) Whereas median durations based on simple tabulations of observed ranges are biased by stratigraphic resolution, our estimates of median duration, extinction rate, and completeness are not biased.(3) The shorter geologic ranges of mammalian species relative to those of bivalves cannot be attributed to a difference in preservation potential. However, we cannot rule out the contribution of taxonomic practice to this difference. (4) In the groups studied, completeness (proportion of species [trilobites, bivalves, mammals] or genera [crinoids] preserved) ranges from 60% to 90%. The higher estimates of completeness at smaller geographic scales support previous suggestions that the incompleteness of the fossil record reflects loss of fossiliferous rock more than failure of species to enter the fossil record in the first place.

Foote, M.; Raup, D. M.

1996-01-01

171

The effect of stratigraphic uncertainty on repository performance  

SciTech Connect

One source of uncertainty in calculating radionuclide releases from a potential radioactive-waste at Yucca Mountain, Nevada, is uncertainty in the unsaturated-zone stratigraphy. Uncertainty stratigraphy results from sparse drillhole data; possible variations in stratigraphy are modeled using the geostatistical method of indicator simulation. One-dimensional stratigraphic columns are generated and used for calculations of groundwater flow and radionuclide transport. There are indications of a dependence of release on hydrogeologic-unit thicknesses, but the resulting variation in release is smaller than variations produced by other sources of uncertainty.

Wilson, M.L. [Sandia National Labs., Albuquerque, NM (United States); Robey, T.H. [Spectra Research Inst., Albuquerque, NM (United States)

1994-08-01

172

The 1911 Quadrant offshore Namibia; Exploration in a virgin basin  

SciTech Connect

As a result of the first licensing round in independent Namibia, the Namibian authorities in 1992 awarded five offshore licenses to five different companies or groups of companies. License no. 001 was awarded in 1992 to a group consisting of three Norwegian oil companies, Norsk Hydro, Saga Petroleum and Statoil, with Hydro as the operator. Somewhat later Bow Valley Energy (now Talisman Energy) farmed in. Since 1992 a seismic survey of 7200 km has been acquired over the license area that covers 11.619 sq. Km of the Walvis Basin. This basin was undrilled until the 1911/15-1 well was finished at a depth of 4586mRKB in early 1994. The sedimentary succession of the 1911/15-1 well reflects a depositional history that postdates the Neocorman Etendeka plateau basalts found onshore Namibia. After the onset of the drift phase in late Hauterivian times, the Walvis Basin subsided and eventually a marine transgression took place. Shallow marine platform sedimentation then prevailed until an Albian tectonic event resulted in complex block faulting and the formation of several sub basins. Subsequent volcanic activity created a series of volcanic centres localized on the Walvis Ridge bathymetric feature. In early Late Cretaceous the Southern African craton was uplifted relative to the shelf, leading to the formation of large scale westward prograding wedges. Later sedimentation largely followed the evolution of a passive continental margin, responding to relative sealevel changes and paleoclimate. A stratigraphic breakdown of the Northern Namibian offshore is proposed, and compared to South African and Angolan nomenclature.

Holtar, E.; Forsberg, A.

1995-08-01

173

Project Quality of OffShore Virtual Teams Engaged in Software Requirements Analysis: An Exploratory Comparative Study  

Microsoft Academic Search

The off-shore software development companies in countries such as India use a global delivery model in which initial requirement analysis phase of software projects get executed at client locations to leverage frequent and deep interaction between user and developer teams. Subsequent phases such as design, coding and testing are completed at off-shore locations. Emerging trends indicate an increasing interest in

Dhruv Nath; Varadharajan Sridhar; Monica Adya; Amit Malik

2008-01-01

174

Fatigue handbook: Offshore steel structures  

SciTech Connect

The contents of this book are: Overview of Offshore Steel Structures; Loads on Ocean Structures; Fracture Mechanics As a Tool in Fatigue Analysis; Basic Fatigue Properties of Welded Joints; Significance of Defects; Improving the Fatigue Strength of Welded Joints; Effects of Marine Environment and Cathodic Protection on Fatigue of Structural Steels Fatigue of Tubular Joints; Unstable Fracture; Fatigue Life Calculations; and Fatigue in Building Codes Background and Applications.

Almarnaess, A.

1985-01-01

175

Development and evaluation of the offshore and coastal dispersion model  

SciTech Connect

The Offshore and Coastal Dispersion (OCD) model has been developed for the Minerals Management Service (MMS) to determine the impact of offshore and onshore emissions from point sources on the air quality of coastal regions. Constructed on the framework of the EPA guideline model MPTER, the OCD model incorporates overwater plume transport and dispersion as well as changes that occur as the plume crosses the shoreline. Hourly meteorological data are needed from both offshore and onshore locations, including wind direction and speed, mixing height, overwater air temperature and relative humidity, and the sea surface temperature. Observed turbulence intensities are preferred by the model but are not mandatory. Dispersion coefficients are proportional to turbulence intensities. A virtual source technique is used to change the rate of plume growth as the overwater plume intercepts the overland internal boundary layer. The continuous shoreline fumigation case is treated using an approach suggested by Deardorff and Willis. Calculation of plume reflection from elevated terrain follows the Rough Terrain Dispersion Model (RTDM). The OCD model and the modified EPA model used as an interim model for overwater applications by the MMS were tested with measurements from three offshore tracer experiments. The OCD model was shown to be a clear improvement over the EPA model and was officially approved by the MMS in March 1985.

Hanna, S.R.; Schulman, L.L.; Paine, R.J.; Pleim, J.E.; Baer, M.

1985-10-01

176

Stratigraphic mapping of hydrated phases in Western Ius Chasma, Mars  

NASA Astrophysics Data System (ADS)

Recent mapping with the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité (OMEGA) has revealed a wide range of hydrated minerals throughout Valles Marineris. Noctis Labyrinthus has interbedded polyhydrated and monohydrated sulfates, with occasional beds of nontronite (Weitz et al. 2010, Thollot et al. 2012). Tithonium Chasma has interbedded poly- and monohydrated sulfates (Murchie et al. 2012); Juventae has poly- and monohydrated sulfates and an anhydrous ferric hydroxysulfate-bearing material (Bishop et al. 2009); and Melas and Eastern Candor contain layers of poly- and monohydrated sulfates (e.g., Roach et al. 2009). Though each chasm displays its own mineralogy, in general, the eastern valles tend to be dominated by layered sequences with sulfates; whereas, the far western valles (Noctis Labyrinthus) has far more mineral phases, possibly due to a wider variety of past environments or processes affecting the area. Ius Chasma, which is situated between Noctis Labyrinthus and the eastern valles and chasmata, also displays a complex mineralogy, with polyhydrated sulfates, Fe/Mg smectites, hydrated silica, and kieserite (e.g. Roach et al. 2010). Here, we present mapping of recently acquired CRISM observations over Ius Chasma, combining the recent CRISM cubes with topographic terrains produced using High Resolution Stereo Camera (HRSC) data from the Mars Express spacecraft. Stratigraphic columns are produced along the length of Ius Chasma, and compared to stratigraphic columns produced throughout the Valles Marineris

Cull, S.; McGuire, P. C.; Gross, C.; Dumke, A.

2013-12-01

177

Ichnofabric and siliciclastic depositional systems: Integration for sequence stratigraphic analysis  

SciTech Connect

Much previous research on biogenic sedimentary structures has established how ichnofacies (assemblages of discrete trace fossils) vary within marine depositional systems. However, studies aimed at understanding the distribution of ichnofabric (sedimentary rock fabric resulting from biogenic reworking) have only recently been attempted. Because ichnofabric can be recorded using a semi-quantitative series of ichnofabric indices (ii), its distribution in marine sedimentary rocks can be easily recorded through vertical sequence analysis. Thicknesses of strata recording different ichnofabric indices can be logged from stratigraphic sections or cores. These data are best displayed in histograms as percent of ii recorded from the total thickness measured. These ichnofabric histograms (ichnograms) show variable but distinctive distributions for genetic units such as facies within systems tracts of siliciclastic depositional sequences. An average ichnofabric index for any genetic sedimentary unit can also be computed from the data used to construct ichnograms. Because skeletal fossils are typically much less commonly preserved in siliciclastic than carbonate depositional systems, such ichnofabric analyses have the potential of providing an important new line of evidence for depositional systems and sequence stratigraphic analysis of siliciclastic strata. In petroleum exploration results from completing analyses of ichnofabric distribution could provide important information including: (1) systems tracts with fine-grained facies that have relatively low ichnofabric values are potential source beds; and (2) petroleum reservoirs that occur in coarse episodically deposited beds are more likely to from in systems tracts with facies that have low rather than high ichnofabric values.

Bottjer, D.J. (Univ. of Southern California, Los Angeles (United States)); Droser, M.L. (Univ. of California, Riverside (United States))

1991-03-01

178

Significance of Quaternary and Experimental Fluvial Systems to Interpretation of the Stratigraphic Record  

NASA Astrophysics Data System (ADS)

Studies of Quaternary and experimental fluvial systems provide significant insight for interpretation of fluvial deposits in the stratigraphic record, ranging from measurement of processes and relevant scales of key architectural elements, to process-based understanding of fluvial systems in sequence stratigraphic models. One key advantage for Quaternary and experimental systems is they commonly provide the ability to test, in a classical verification or falsification sense, interpretations, models and their alternatives that were developed from the stratigraphic record alone. First, scaling relationships developed from Quaternary fluvial deposits can be utilized to constrain interpretations of ancient strata, as well as predict the scale of channel fills, channel-belt sand bodies, and incised valleys. Scaling relationships are defined by power laws, with absolute dimensions that scale to drainage area, water flux, and sediment flux. Width-to-thickness ratios for channel fills range from 10-20:1, whereas channel-belt sand bodies upstream from backwater effects commonly range from 70-300:1, and 20-40:1within the backwater zone, where channel migration is limited. Quaternary incised valleys range from 25-150 m in thickness, and ~5-100 km in width, with width-to-thickness ratios of ~500-800. Scales of Quaternary channel fills and channel-belt sand bodies overlap are consistent with compilations from the ancient record. However, even the smallest Quaternary incised valleys reside in the uppermost part of the domain of published ancient valleys, with ancient examples overlapping significantly with modern channel fills and channel belts. We suggest that many ancient examples have been overinterpreted because of a lack of objective criteria for differentiating channel fills, channel belts, and incised valleys. Second, incised valleys have long played a key role in sequence-stratigraphic interpretations. For incised valleys in the stratigraphic record, either in outcrop or subsurface data, the sequence boundary is most commonly defined by the base of fluvial incision, which demarcates a significant basinward shift of facies, and is assumed to be an unconformity that everywhere separates younger strata above from older strata below. This classical interpretation is derived from a model for fluvial incision and sediment bypass during relative sea-level fall: fluvial deposits that rest on the sequence boundary are commonly assumed to represent filling of an empty container during late lowstand or early transgression. However, the model of fluvial incision and sediment bypass during relative sea-level fall has never been verified and does not stand up to scrutiny in Quaternary systems or experiments. Moreover, sediment bypass and deposition within incised valleys are not mutually exclusive: a large proportion of fluvial sediment is in transit over the duration of a base-level cycle, even though erosion and channel-belt deposition continuously redefines the valley shape, and at any one point the basal valley-fill surface is the same age as fluvial deposits that rest on top of it. Last, extension of valleys across a newly emergent shelf is accompanied by linked channel-belt deposition and delta progradation, such that the base of fluvial incision does not qualify as an unconformity or meet traditional criteria for a sequence boundary.

Blum, M. D.; Martin, J. M.

2012-12-01

179

Offshoring in the Semiconductor Industry: Historical Perspectives  

Microsoft Academic Search

Semiconductor design is a frequently-cited example of the new wave of offshoring and foreign-outsourcing of service sector jobs. It is certainly a concern to U.S. design engineers themselves. In addition to the current wave of white-collar outsourcing, the industry also has a rich experience with offshoring of manufacturing activity. Semiconductor companies were among the first to invest in offshore facilities

Clair Brown; Greg Linden

2005-01-01

180

27. Annual Offshore Technology Conference: 1995 Proceedings. Volume 4: Field drilling and development systems  

SciTech Connect

This conference proceedings represents volume 4 of a four volume set of offshore oil and gas operation and development. This proceedings includes papers dealing with subsea flowlines and connectors; well completion practices; new technologies associated with subsea wellheads; multiphase flow pumping and flow meters; and materials testing procedures for well tubulars. It also has a section on the overall technology utilization in developing the offshore areas of Brazil and Norway.

NONE

1995-12-31

181

Handling two-phase gas condensate flow in offshore pipeline systems  

SciTech Connect

Special flow problems occur in offshore pipelines transmitting gas to processing plants onshore: as the hot, freshly produced gas cools en route, the pipeline pressure falls and the heavier hydrocarbons condense. To aid drilling operators in designing condensate-separation and transport facilities, the following should be considered: (1) temperature behavior and two-phase flow in offshore lines, (2) condensate handling and slug-catcher design on booster platforms, (3) onshore separation terminal operation, and (4) the testing of industrial liquid separators.

Oranje, L.

1983-04-18

182

Numerical and experimental analysis of a retrievable offshore loading facility  

SciTech Connect

ROLF (Retrievable Offshore Loading Facility) has been proposed as an alternative offshore oil export tanker loading system for the North Sea. The system consists of a flexible riser ascending from the seabed in a lazy wave configuration to the bow of a dynamically positioned tanker. In order to supplant and support the numerical analyses performed to design the system, an extensive model test program was carried out in a 3D offshore basin at scale 1:50. A model riser with properties equivalent to the properties of the oil filled prototype riser installed in seawater was tested in several combinations of waves and current. During the tests the forces at the bow of the tanker and at the pipeline end manifold were measured together with the motions of the tanker and the riser. The riser motions were measured by means of a video based 3D motion monitoring system. Of special importance was accurate determination of the minimum bending radius for the riser. This was derived based on the measured riser motions. The results of the model tests were compared to numerical analyses by an MCS proprietary riser analysis program.

Sterndorff, M.J. [Danish Hydraulic Inst., Hoersholm (Denmark); O`Brien, P. [MCS International, Aberdeen (United Kingdom)

1995-12-31

183

1991 worldwide offshore contractors and equipment directory  

SciTech Connect

This book is the information source-book for the international offshore oil industry. Within this single convenient reference you'll find addresses, phone numbers, telex, fax and cable listings for more than 3,500 companies and their key personnel in the drilling, workover, construction, service/supply/manufacturers, geophysical, diving and transportation segments of the offshore industry. Along with this vital contact information, the authors include such pertinent data as rig specifications, ownership, an equipment index, a company index and a current survey of offshore production systems from Offshore Incorporating the Oilman.

Not Available

1991-01-01

184

Geological history of the Flemish Pass Basin, offshore Newfoundland  

SciTech Connect

In this paper the authors present a seismic-stratigraphic interpretation of the Mesozoic and Tertiary geologic history of the Flemish Pass Basin, offshore Newfoundland, based on seismic data and data from seven wells that were integrated on the BP subsurface integrated interpretation system (SIIS). Four megasequences are identified. Megasequence 1 (MSI) is Triassic to lower Berriasian, and includes poorly known sediments associated with Triassic-Early Jurrasic rifting prior to spreading between the North African and American continents. The uppermost mappable unconformity-bounded unit within MSI contains major Kimmeridgian to Portlandian marine source rocks deposited in two east-west-trending subbasins in the Baccalieu and Gabriel areas. During the early Berrasian, pronounced rifting linked to the subsequent spreading of Iberia from the Grand Banks (Barremian-Aptian) led to regional deepening and deposition of clastic sediments (MS2) in two northeast-southwest-trending, fault-bounded subbasins in the Baccalieu and Gabriel areas. In the Aptian, Early Cretaceous subbasins were inverted due to strike-slip movement as extension assumed a northeast-southwest orientation prior to movement of Greenland/Europe away from Labrador (Albian). MS3 sediments fill northwest-southeast trending fault-bounded depocenters typically located on areas that had formed highs during Early Cretaceous. Postrift sedimentation continued from the Albian( ) to the present with Upper Cretaceous pelagic limestone and later clastic sediment deposition. 37 refs., 19 figs., 1 tab.

Foster, D.G.; Robinson, A.G. (BP Exploration Operating Company Ltd., Uxbridge (United Kingdom))

1993-04-01

185

Offshore Coastal Wind Speed Gradients: issues for the design and development of large offshore windfarms  

E-print Network

indicates that within the coastal zone, wind speeds at typical turbine hub-heights can change by 2 m/s over the area of the wind farm appear to be small and negligible. 1. INTRODUCTION As large offshore wind farmsOffshore Coastal Wind Speed Gradients: issues for the design and development of large offshore

Pryor, Sara C.

186

Experimental procedures on floating offshore plate subjected to ground motion  

SciTech Connect

This paper is concerned with experimental procedures for studying the dynamic behavior of floating offshore structures subjected to seaquakes. Three experimental procedures have been presented as vibration tests on the dynamic behavior of floating offshore structures. The first experimental procedure is performed using a large-scaled experimental water tank fitted with a vertical vibrator in the tank floor. The second one is carried out by using a small-scaled experimental water tank fitted with a vertical vibrator in the tank floor. The third one, which is the most convenient experimental procedure, is vibration tests of the cylindrical vessel in which the model is contained. Based on the experimental results, discussion focuses on the change in the seaquake response of flexible floating plate due to the plate flexibility and anchor stiffness through a comparative study of three experimental procedures.

Endo, Ryuji; Ando, Masahiro; Kato, Takehiko [Polytechnic Univ., Sagamihara (Japan); Hamamoto, Takuji [Musashi Inst. of Tech., Tokyo (Japan); Tosaka, Nobuyoshi [Nihon Univ., Chiba (Japan)

1994-12-31

187

76 FR 11503 - National Offshore Safety Advisory Committee; Vacancies  

Federal Register 2010, 2011, 2012, 2013, 2014

...safety and training related to offshore exploration and construction...representing enterprises specializing in offshore drilling. To be eligible, applicants for...exploration for and the recovery of offshore mineral resources....

2011-03-02

188

76 FR 39410 - National Offshore Safety Advisory Committee; Vacancies  

Federal Register 2010, 2011, 2012, 2013, 2014

...have recent practical experience on vessels or offshore units involved in the offshore mineral and energy industry; (d) One member representing enterprises specializing in offshore drilling; and, (e) One member representing...

2011-07-06

189

77 FR 17491 - National Offshore Safety Advisory Committee  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF HOMELAND SECURITY Coast Guard [Docket...National Offshore Safety Advisory Committee...Department of Homeland Security. ACTION: Committee...National Offshore Safety Advisory Committee...and gas offshore industry. These meetings...New Orleans Arts Hotel, 700...

2012-03-26

190

Venusian extended ejecta deposits as time-stratigraphic markers  

NASA Technical Reports Server (NTRS)

Use of impact crater ejects at time-stratigraphic markers was established during lunar geologic mapping efforts. The basic premise is that the deposition of impact ejecta, either by itself or mixed with impact-excavated material, is superimposed on a surface. The deposit becomes an observable, mappable unit produced in a single instant in geologic time. Up to two-thirds of Venus craters exhibit extended ejecta deposits. A reconnaissance survey of 336 craters (about 40 percent of the total population) was conducted. About half the craters examined were located in and around the Beta-Atla-Themis region, and half were spread over the western hemisphere of the planet. The survey was conducted using primarily C1-MIDR images. The preliminary survey shows: (1) of the 336 craters, 223 were found to have extended ejecta deposits. This proportion is higher than that found in other Venus crater databases by up to a factor of 2. (2) 53 percent of all extended ejecta craters were unambiguously superimposed on all volcanic and tectonic units. Crater Annia Faustina's associated parabolic ejecta deposit is clearly superimposed on volcanic flows coming from Gula Mons to the west. Parabola material from Faustina has covered the lava flows, smoothing the surface and reducing its specific backscatter cross section. The stratigraphy implies that the parabola material is the youngest observable unit in the region. (3) 12 percent of extended ejecta deposits are superimposed by volcanic materials. Crater Hwangcini has extended ejecta that has been covered by volcanic flows from a dome field to the northwest, implying that the volcanic units were emplaced subsequent to the ejecta deposit and are the youngest units in the locality. (4) It is difficult to determine the stratigraphic relationships of the remaining extended ejecta deposits in SAR at C1-MIDR resolution. Examination of higher resolution images and application of the other Magellan datasets in systematic manner should resolve most of the ambiguous cases. Results from the preliminary survey indicate that extended ejecta deposits are effective time-statigraphic markers for the localities. If stratigraphic relationships between the deposits and surrounding units are studied on a case-by-case basis over the whole planet, they should provide useful constraints on Venus history and development of the surface through time. The continuation of the research will expand the study to include the entire crater population and the Magellan emissivity, altimetry, reflectivity, and rms slope datasets.

Izenberg, Noam R.

1992-01-01

191

Venusian extended ejecta deposits as time-stratigraphic markers  

NASA Astrophysics Data System (ADS)

Use of impact crater ejects at time-stratigraphic markers was established during lunar geologic mapping efforts. The basic premise is that the deposition of impact ejecta, either by itself or mixed with impact-excavated material, is superimposed on a surface. The deposit becomes an observable, mappable unit produced in a single instant in geologic time. Up to two-thirds of Venus craters exhibit extended ejecta deposits. A reconnaissance survey of 336 craters (about 40 percent of the total population) was conducted. About half the craters examined were located in and around the Beta-Atla-Themis region, and half were spread over the western hemisphere of the planet. The survey was conducted using primarily C1-MIDR images. The preliminary survey shows: (1) of the 336 craters, 223 were found to have extended ejecta deposits. This proportion is higher than that found in other Venus crater databases by up to a factor of 2. (2) 53 percent of all extended ejecta craters were unambiguously superimposed on all volcanic and tectonic units. Crater Annia Faustina's associated parabolic ejecta deposit is clearly superimposed on volcanic flows coming from Gula Mons to the west. Parabola material from Faustina has covered the lava flows, smoothing the surface and reducing its specific backscatter cross section. The stratigraphy implies that the parabola material is the youngest observable unit in the region. (3) 12 percent of extended ejecta deposits are superimposed by volcanic materials. Crater Hwangcini has extended ejecta that has been covered by volcanic flows from a dome field to the northwest, implying that the volcanic units were emplaced subsequent to the ejecta deposit and are the youngest units in the locality. (4) It is difficult to determine the stratigraphic relationships of the remaining extended ejecta deposits in SAR at C1-MIDR resolution. Examination of higher resolution images and application of the other Magellan datasets in systematic manner should resolve most of the ambiguous cases. Results from the preliminary survey indicate that extended ejecta deposits are effective time-statigraphic markers for the localities. If stratigraphic relationships between the deposits and surrounding units are studied on a case-by-case basis over the whole planet, they should provide useful constraints on Venus history and development of the surface through time. The continuation of the research will expand the study to include the entire crater population and the Magellan emissivity, altimetry, reflectivity, and rms slope datasets.

Izenberg, Noam R.

1992-12-01

192

OWL representation of the geologic timescale implementing stratigraphic best practice  

NASA Astrophysics Data System (ADS)

The geologic timescale is a cornerstone of the earth sciences. Versions are available from many sources, with the following being of particular interest: (i) The official International Stratigraphic Chart (ISC) is maintained by the International Commission for Stratigraphy (ICS), following principles developed over the last 40 years. ICS provides the data underlying the chart as part of a specialized software package, and the chart itself as a PDF using the standard colours; (ii) ITC Enschede has developed a representation of the timescale as a thesaurus in SKOS, used in a Web Map Service delivery system; (iii) JPL's SWEET ontology includes a geologic timescale. This takes full advantage of the capabilities of OWL. However, each of these has limitations - The ISC falls down because of incompatibility with web technologies; - While SKOS supports multilingual labelling, SKOS does not adequately support timescale semantics, in particular since it does not include ordering relationships; - The SWEET version (as of version 2) is not fully aligned to the model used by ICS, in particular not recognizing the role of the Global Boundary Stratotype Sections and Point (GSSP). Furthermore, it is distributed as static documents, rather than through a dynamic API using SPARQL. The representation presented in this paper overcomes all of these limitations as follows: - the timescale model is formulated as an OWL ontology - the ontology is directly derived from the UML representation of the ICS best practice proposed by Cox & Richard [2005], and subsequently included as the Geologic Timescale package in GeoSciML (http://www.geosciml.org); this includes links to GSSPs as per the ICS process - key properties in the ontology are also asserted to be subProperties of SKOS properties (topConcept and broader/narrower relations) in order to support SKOS-based queries; SKOS labelling is used to support multi-lingual naming and synonyms - the International Stratigraphic Chart is implemented as a set of instances of classes from the ontology, and published through a SPARQL end-point - the elements of the Stratigraphic chart are linked to the corresponding elements in SWEET (Raskin et al., 2011) and DBpedia to support traceability between different commonly accessed representations. The ontology builds on standard geospatial information models, including the Observations and Measurements model (ISO 19156), and GeoSciML. This allows the ages given in the chart to be linked to the evidence basis found in the associated GeoSciML features.

Cox, S. J.

2011-12-01

193

Shallow stratigraphic controls on fluid and solute fluxes across the sediment-water interface of an estuary (Invited)  

NASA Astrophysics Data System (ADS)

Geologic heterogeneity influences the discharge of fresh groundwater to coastal waters and the circulation of saline surface water across the sediment-water interface. Here, we quantify the spatial distribution of shallow surface water-groundwater mixing, associated geochemistry, and submarine groundwater discharge (SGD) near a paleovalley feature in Indian River Bay, Delaware using a hand resistivity probe, seepage meters, and pore water samples. In the interfluve far from the paleovalley, fresh groundwater discharges rapidly near the coast. The discharging groundwater is relatively oxygenated, low in DOC, and high in nitrate. Short residence times in the shallow mixing zone provide little opportunity for geochemical transformation in discharging groundwater. In contrast, near the peat-covered paleovalley, fresh groundwater discharges farther offshore along the paleovalley margins at a moderate rate. Fresh groundwater near the paleovalley is relatively reducing, lower in nitrate, and higher in iron(II) and sulfide. Excess iron(II) in shallow pore water indicates iron reduction along shallow flow paths. In locations with little to no fresh groundwater discharge, the depth of saline surface water exchange is generally greater, and elevated sulfide, ammonium, and DOC in the shallow sediments likely indicate reduction of surface water-derived sulfate and microbial oxidation of organic matter. By modifying patterns of groundwater discharge and the nature of shallow mixing zones, paleovalleys and other stratigraphic features influence the geochemistry of fresh SGD and redox reactions near the sediment-water interface, affecting rates and patterns of geochemical fluxes to coastal surface waters.

Sawyer, A. H.; Lazareva, O.; Chan, C. S.; Crespo, K.; Stieglitz, T. C.; Michael, H. A.

2013-12-01

194

Drilling rate for the Cerro Prieto stratigraphic sequence  

SciTech Connect

Drilling practice at the field has been modified in several ways as better information is being obtained. The stratigraphic sequence of the area is made up of three sedimentary rock units of deltaic origin having different densities. These units have been named non-consolidated, semi-consolidated, and consolidated rocks; the thermal reservoirs are located in the latter. To investigate how the drilling rates are affected by the three rock units, plots of drilling advance versus time were made for a large number of wells. A typical plot is shown and drilling rates are practically constant in three different zones; that is, the drilling rate has only two breaks or changes in slope.

Prian C, R.

1981-01-01

195

Stratigraphical distribution of the Ordovician conodont Erraticodon Dzik in Argentina  

NASA Astrophysics Data System (ADS)

Three different species of the Ordovician genus Erraticodon Dzik are described and illustrated. Erraticodon patu Cooper is reported from the Lower-Midde Ordovician strata of the Acoite and Alto del Cóndor formations. E. cf. Erraticodon balticus and Erraticodon hexianensis from Middle Ordovician carbonate deposits of the San Juan Formation are analyzed and compared to specimens of these species from Australia, China, Newfoundland, and Baltica. E. patu and E. hexianensis are recorded for first time in the San Juan Formation of Precordillera. The elements of E. cf. E. balticus resemble closely E. balticus Dzik but lack the important denticle on the posterior process of the S elements. An evaluation of the stratigraphic occurrences of these species relative to those of key Lower and Middle Ordovician conodont species such as Trapezognathus diprion Lindström, Oepikodus intermedius Serpagli, Baltoniodus triangularis (Lindström), Baltoniodus navis Lindström, Yangtzeplacognathus crassus (Chen and Zhang) and Eoplacognathus pseudoplanus (Viira) indicates they value for biostratigraphic correlation.

Heredia, S.; Carlorosi, J.; Mestre, A.; Soria, T.

2013-08-01

196

Hydrocarbon traps along Louisiana offshore  

SciTech Connect

A compilation of potential hydrocarbon trap types has been assembled for the Louisiana offshore, from coastal plain to abyssal plain. These potential traps are listed according to paleophysiographic provinces: coastal plain, shelf, shelf break, upper slope, middle slope, lower slope, and abyssal plain. Characteristics of each trap type are tabulated. The characteristics include tectonics, regional and local sedimentation rates and types, position within an evolving sequence as determined by sequence stratigraphy, duration of reservoir and/or trap creation, and sea level position. Regional geologic processes, such as salt tectonics, and approximate rates at which they operate are also listed.

Lowrie, A.; Sullivan, N.

1989-03-01

197

Chemical Contaminants as Stratigraphic Markers for the Anthropocene  

NASA Astrophysics Data System (ADS)

Thousands and even millions of years from now, widespread anthropogenic contaminants in sediments would likely persist, incorporated into the geological record. They would inadvertently preserve evidence of our present era (informally designated as the Anthropocene Epoch) characterized by large human populations engaged in intensive industrial and agricultural activities. Hypothetical geologists in the distant future would likely find unusually high concentrations of a wide variety of contaminants at stratigraphic levels corresponding to our present time, analogous to the iridium anomaly marking the bolide impact event at the close of the Cretaceous Period. These would include both organic and inorganic substances, such as industrially-derived heavy metals (e.g., Hg, Pb, Cr, Zn) and hydrocarbons, both petrogenic (derived directly from petroleum) and pyrogenic (combustion products). While there are natural sources for these materials, such as volcanic eruptions, wildfires, and oil seeps, their co-occurrence would provide a signature characteristic of human activity. Diagnostic assemblages of organic compounds would carry an anthropogenic imprint. The distribution of polycyclic aromatic hydrocarbons (PAHs) in a sediment sample could distinguish between natural and human sources. Stable isotopic signatures would provide additional evidence. Concentrations of contaminants in the sedimentary record would increase exponentially with increasing proximity to urban source areas, where at present billions of people are collectively consuming vast quantities of fossil fuels and generating large amounts of waste. Aolian and marine transport prior to deposition has been seen at present to globally redistribute detectable amounts of contaminants including Hg and PAHs, even at great distances from principal source areas. For organic contaminants, deposition in an anoxic sedimentary environment could insure their preservation, increasing the likelihood of their inclusion in the long-term stratigraphic record, establishing markers of the Anthropocene Epoch for millions of years to come.

Kruge, M. A.

2012-12-01

198

Searching for stratigraphic traps in the Neuquen basin of Argentina  

SciTech Connect

Amoco Argentina oil Company secured a farm-in from YPF (50-50 partnership) over the blocks CN-VIII and ON-IX in the Neuquen basin of Argentina. Primary reservoir horizons are Late Jurassic and Early Cretaceous eolian sands. The petrophysical properties of these dunal sands contrast-sometimes sharply-with those of the silts and shales of similar age in the immediate area. Initial evaluation of the blocks had recognized stratigraphic potential associated with the dunal facies, especially in the CN-VIII block. The presence of reservoir quality Avile sands (Barremian age, 18-20% porosity) was mapped on the CN-VIII block directly from older vintage seismic. (1) Seismic Acquisition: Amoco shot approximately 400 km of high resolution 120-fold seismic in late 1994 to high-grade those leads identified on the old seismic. The CN-VIII block is partially covered by basalts of varying thickness. The Amoco survey resulted in an improved penetration through the basalts; it also had a much higher frequency content and yielded superior bed resolution than any previous survey in the area. (2) Seismic Processing and Modeling: Amoco reprocessed inhouse several key lines over producing fields in the immediate area and approximately 200 km of seismic from the 1994 survey in the CN-VIll block for detailed amplitude analysis. Seismic amplitude models [including (1) 2-D stratigraphic pinchout models describing the presence of porous sand lenses, and (2) AVO models] tie the 1994 data very well. (3) Integrated Seismic Interpretation and Reduction of Technical RISK: The integration of various disciplines (Petrophysics, Geophysics, Geology, and Engineering) resulted in the calibration/ranking of seismic responses observed over the CN-VIII area, thus substantially reducing the RISK on trap definition, reservoir quality, seal, and product associated with the early leads.

Blangy, J.P.; Follis, M.; Tavella, G.; Wright, C.

1996-08-01

199

Seismic attenuation of the inner core: Viscoelastic or stratigraphic?  

USGS Publications Warehouse

Broadband velocity waveforms of PKIKP in the distance range 150??to 180??are inverted for inner core attenuation. A mean Q?? of 244 is determined at 1 Hz from 8 polar and 9 equatorial paths. The scatter in measured Q-1 exceeds individual error estimates, suggesting significant variation in attenuation with path. These results are interpreted by (1) viscoelasticity, in which the relaxation spectrum has a low-frequency corner near or slightly above the frequency band of short-period body waves, and by (2) stratigraphic (scattering) attenuation, in which attenuation and pulse broadening are caused by the interference of scattered multiples in a velocity structure having rapid fluctuations along a PKIKP path. In the scattering interpretation, PKIKP attenuation is only weakly affected by the intrinsic shear attenuation measured in the free-oscillation band. Instead, its frequency dependence, path variations, and fluctuations are all explained by scattering attenuation in a heterogeneous fabric resulting from solidification texturing of intrinsically anisotropic iron. The requisite fabric may consist of either single or ordered groups of crystals with P velocity differences of at least 5% and as much as 12% between two crystallographic axes at scale lengths of 0.5 to 2 km in the direction parallel to the axis of rotation and longer in the cylindrically radial direction, perpendicular to the axis of rotation.Broadband velocity waveforms of PKIKP in the distance range 150?? to 180?? are inverted for inner core attenuation. A mean Q?? of 244 is determined at 1 Hz from 8 polar and 9 equatorial paths. The scatter in the measured Q-1 exceeds individual error estimates, indicating significant variation in attenuation with path. The results are interpreted by viscoelasticity and stratigraphic (scattering) attenuation.

Cormier, V.F.; Xu, L.; Choy, G.L.

1998-01-01

200

Cost of Offshore Wind Energy Charlene Nalubega  

E-print Network

Cost of Offshore Wind Energy water as well as on land based wind farms. The specific offshore wind energy case under consideration kilowatt Hour will be determined. Wind Energy has been around for a very long time. It started as out

Mountziaris, T. J.

201

Offshore investment funds: monsters in emerging markets?  

Microsoft Academic Search

Relative to onshore funds, offshore funds are subject to less taxes and regulation. So they may trade more aggressively and do so in ways that could destabilize the emerging markets. We study the behavior of the offshore funds in Korea and compare them with the onshore funds. Evidence suggests that they do trade more frequently. However, they do not engage

Woochan Kim; Shang-Jin Wei

2002-01-01

202

OFFSHORE WIND FARMS Guidance note for Environmental  

E-print Network

OFFSHORE WIND FARMS Guidance note for Environmental Impact Assessment In respect of FEPA and CPA requirements Version 2 - June 2004 #12;Offshore Wind Farms: Guidance Note for Environmental Impact Assessment and Aquaculture Science (CEFAS) on behalf of the Marine Consents and Environment Unit (MCEU) © Crown Copyright

203

System Reliability Assessment of Offshore Pipelines  

Microsoft Academic Search

The title of this thesis, System Reliability Assessment of Offshore Pipelines, portrays the application of probabilistic methods in assessing the reliability of these structures. The main intention of this thesis is to identify, apply and judge the suitability of the probabilistic methods in evaluating the system reliability of offshore pipelines subjected to corrosion. The analysis was first emphasized on interpreting

Z. Mustaffa

2011-01-01

204

44 MArch 2006 Can offshore aquaculture  

E-print Network

44 MArch 2006 Can offshore aquaculture of carnivorous fish be sustainable? Case studies from and pollution concerns sug- gest that major environmental benefits are to be gained by moving cage aquaculture development of offshore aquaculture through university-industry-government partnerships. Emerging technology

Miami, University of

205

Domestic Options to Offshore Oil and Gas.  

ERIC Educational Resources Information Center

The continuing controversey over offshore oil/gas has given impetus to searching for domestic energy alternatives. The need for and types of several alternative sources are discussed. Indicates that the United States needs to pursue both offshore and other domestic liquid-fuel sources if it is to avoid becoming increasingly dependent on imports.…

Kash, Don E.

1983-01-01

206

Sequence-stratigraphic and mass-balance analysis of experimental stratigraphy  

NSDL National Science Digital Library

Sequence-stratigraphic and mass-balance analysis of experimental stratigraphy. Students are charged with evaluating how basin subsidence geometry influences depositional patterns. In addition to providing practice applying sequence-stratigraphic methods, this project builds quantitative data-analysis and writing skills.

Liz Hajek

207

Western interior cretaceous project (WIK): North-south stratigraphic section along geographic center of basin  

Microsoft Academic Search

This stratigraphic section extends from central Montana through the Powder River, Denver, and Raton basins to the San Juan basin of New Mexico. Four east-west sections across the Cretaceous basin, presented at this meeting, are tied together along the geographic center of the basin where the strata are largely marine in origin. Lithostratigraphic, chronostratigraphic, and sequence stratigraphic data are presented.

T. D. Fouch; T. S. Dyman; C. M. Molenaar; F. G. Ethridge; R. J. Weimer

1991-01-01

208

Rupture lengths and temporal history of significant earthquakes on the offshore and north coast segments of the Northern San Andreas Fault based on turbidite stratigraphy  

NASA Astrophysics Data System (ADS)

74 piston, gravity and jumbo Kasten cores were collected from channel and canyon systems draining the northern California continental margin to investigate the record of periodic Holocene turbidites for possible connection to large magnitude earthquakes on the adjacent Northern San Andreas Fault. Poorly known channel systems were mapped with multibeam sonar to define pathways and channel confluences. Cores sampled all major and many minor channel systems extending from Cape Mendocino to just north of Monterey Bay. Sampling both along and across channels was done and particular attention was paid to channel confluences, as these areas afford opportunities to test for synchronous triggering of turbidity currents. While at sea, all cores were scanned using a GEOTEK multisensor core logger (MSCL), which collects high-resolution photography, P-wave velocity, gamma-ray density, and magnetic susceptibility data from the unsplit cores. Lithology was logged visually, and cores were later imaged with X-radiography. We use 14C ages, relative dating tests at channel confluences, and stratigraphic correlation using physical properties to determine whether turbidites deposited in separate channel systems are correlative, implying they were triggered by a common event. These tests can, in most cases, separate earthquake-triggered turbidity currents from other possible sources. The late Holocene turbidite record off northern California passes these tests for synchronous triggering, and can be correlated with multiple proxies from site to site between Noyo Channel and the latitude of San Francisco. Preliminary comparisons of our event ages with existing and in progress work at onshore coastal sites show good correlation, further circumstantial evidence that the offshore record is primarily earthquake generated. During the last ˜ 2800 yr, 15 turbidites are recognized, including the great 1906 earthquake. Their chronology establishes an average repeat time of ˜ 200 yr, similar to the onshore value of ˜ 230 yr. Along-strike correlation suggests that at least 8 of the youngest 10 of these events ruptured the 320 km distance from the Mendocino Triple Junction to near San Francisco.

Goldfinger, Chris; Morey, Ann E.; Nelson, C. Hans; Gutiérrez-Pastor, Julia; Johnson, Joel E.; Karabanov, Eugene; Chaytor, Jason; Eriksson, Andrew; Shipboard Scientific Party

2007-02-01

209

Episodic event deposits versus stratigraphic sequences—shall the twain never meet?  

NASA Astrophysics Data System (ADS)

In the early half of the 20th century, questions were raised about different rates of deposition reflected in the stratigraphic record and of small gaps or diastems. Even more discussion centered upon rhythms and cycles of deposition—at one extreme were glacial varves and at the other were Carboniferous cyclothems. After World War II, interest in stratigraphic cycles declined. Then the turbidity current revolution stimulated interest in event deposits, which interest has surged again recently with a focus upon storm deposits. Meanwhile, the recent dramatic growth of sequence stratigraphy has rekindled interest in both cyclicity and eustasy. The two themes—events and cycles—should be better integrated, for there is considerable confusion about the interpretation of high-frequency sequences. There is also a need to reconcile the current fad for Milankovitch-related sedimentary cycles versus more or less random event deposits. The most familiar event deposits are turbidites in deep-water and tempestites in shallow-water environments. More subtle are the diastems, which include non-depositional surfaces as well as scoured surfaces. Other processes that can produce event deposits include avalanches and tsunamis. Potentially, any type of event deposit could be mistaken for a sequence boundary. For example, submarine megabreccias could be formed either by a seismic event unrelated to any sea level change, or by slope failure resulting from a eustatic fall associated with a sequence boundary. To surmount the intellectual barrier to alternate interpretations requires careful attention to processes, time resolution, and objective tests for periodicity.

Dott, R. H.

1996-07-01

210

Development of fast wireless detection system for fixed offshore platform  

NASA Astrophysics Data System (ADS)

Offshore platforms' security is concerned since in 1950s and 1960s, and in the early 1980s some important specifications and standards are built, and all these provide technical basis of fixed platform design, construction, installation and evaluation. With the condition that more and more platforms are in serving over age, the research about the evaluation and detection technology of offshore platform has been a hotspot, especially underwater detection, and assessment method based on the finite element calculation. For fixed platform structure detection, conventional NDT methods, such as eddy current, magnetic powder, permeate, X-ray and ultrasonic, etc, are generally used. These techniques are more mature, intuitive, but underwater detection needs underwater robot, the necessary supporting tools of auxiliary equipment, and trained professional team, thus resources and cost used are considerable, installation time of test equipment is long. This project presents a new kind of fast wireless detection and damage diagnosis system for fixed offshore platform using wireless sensor networks, that is, wireless sensor nodes can be put quickly on the offshore platform, detect offshore platform structure global status by wireless communication, and then make diagnosis. This system is operated simply, suitable for offshore platform integrity states rapid assessment. The designed system consists in intelligence acquisition equipment and 8 wireless collection nodes, the whole system has 64 collection channels, namely every wireless collection node has eight 16-bit accuracy of A/D channels. Wireless collection node, integrated with vibration sensing unit, embedded low-power micro-processing unit, wireless transceiver unit, large-capacity power unit, and GPS time synchronization unit, can finish the functions such as vibration data collection, initial analysis, data storage, data wireless transmission. Intelligence acquisition equipment, integrated with high-performance computation unit, wireless transceiver unit, mobile power unit and embedded data analysis software, can totally control multi-wireless collection nodes, receive and analyze data, parameter identification. Data is transmitted at the 2.4GHz wireless communication channel, every sensing data channel in charge of data transmission is in a stable frequency band, control channel responsible for the control of power parameters is in a public frequency band. The test is initially conducted for the designed system, experimental results show that the system has good application prospects and practical value with fast arrangement, high sampling rate, high resolution, capacity of low frequency detection.

Li, Zhigang; Yu, Yan; Jiao, Dong; Wang, Jie; Li, Zhirui; Ou, Jinping

2011-04-01

211

Alternating Authigenic and Carbonate Factory Production within a Cool-water Carbonate Sequence Stratigraphic Framework  

NASA Astrophysics Data System (ADS)

Glaucony and phosphate production is characteristic of low sedimentation rates within low energy, oxygen-depleted environments, and is often associated with condensed sections and unconformities. Glaucony- and phosphate-rich rocks are often interpreted to be associated with sea-level highstands and maximum flooding surfaces, especially in siliciclastic systems. In contrast, our research shows that in the cool-water carbonate realm glaucony and, to an extent, phosphate are connected to lowstands and transgressions, requiring a reversal in the way they are interpreted within a sequence stratigraphic context. The Mid-Tertiary rocks of the Waitaki Basin, South Island, New Zealand, contain a cool-water carbonate and greensand succession formed on the eastern passive margin of the Zealandia continental fragment, and include two major sequence boundaries within a broad regional transgression. The palaeobasin contained an eastern outer shelf volcanic-induced high that acted like a platform rim, from where the basin deepened towards the west. The basal sequence contains a bryozoan grainstone facies that formed a shoal on the eastern volcanic seamount. This grades westward to a quartzose impure wackestone containing terrigenous material derived from low-lying islands of Zealandia far to the west. The overlying sequence boundary forms a karst surface associated with the high in the east, and a firmground in the west, and developed as a result of sea-level fall and lowstand conditions. During these lowstand conditions the terrigenous supply of silt and clay material was moved closer to the Waitaki Basin and this was then available for glauconitisation. Calcareous glaucony- and phosphate-rich greensands accumulated during the subsequent transgression, with the glaucony and phosphate content decreasing through this second sequence to form pure packstones during highstand and early regression. The second sequence boundary overlying these packstones shows similar karst and firmground distribution to the first, and has a similar greensand transgressive sequence deposited above it. In this cool-water setting, where the carbonate factory is located on an offshore volcanic-induced high, authigenic mineral production occurs at lowstand settings. During lowstand, mud-sized terrigenous clay minerals are introduced to the basin from the west, smothering the carbonate factory and supplying the building blocks for glaucony production. Through the transgressive phase this terrigenous clay supply is progressively shut down and the system returns to carbonate production at highstand. Sea-level rise in such an environment encourages the development of the cool-water carbonate factory, and thus a decrease in production from the 'authigenic factory'.

Thompson, N. K.; Reid, C.; Bassett, K. N.

2012-12-01

212

Stratigraphic records of paleogeography and global change from two late Proterozoic basins  

NASA Astrophysics Data System (ADS)

As sediments and volcanic deposits accumulate on Earth's surface, they record information about Earth's climate, the motion of continents, and the evolution of the biosphere. Through the study of ancient stratigraphic sequences, we can gain a window into our planet's varied, and sometimes tumultuous, past. In this dissertation, I employ a combination of field observations, magnetic data, and chemostratigraphic data in the Keweenawan Mid-continent Rift of North America and the Amadeus Basin of Central Australia to study the paleogeography and paleoclimate during and after the transition between the Mesoproterozoic (1.7 to 1.0 billion-years ago) and Neoproterozoic Eras (1.0 to 0.54 billion-years ago). The supercontinent Rodinia formed at the boundary between the Eras and broke apart throughout the Neoproterozoic. Basins that developed as Rodinia rifted apart record large changes in the biogeochemical cycling of carbon and sulfur, the waxing and waning of low-latitude ice sheets, and the progressive oxygenation of the atmosphere that facilitated the evolution of animals. I report high-resolution paleomagnetic data in stratigraphic context from Mamainse Point, Ontario---the most complete succession in the 1.1 billion-year-old Mid-continent Rift. The results demonstrate that previous suggestions of large non-dipolar geomagnetic field components at the time stemmed from low temporal resolution across geomagnetic reversals during a period of rapid plate motion. This result strengthens the framework for evaluating records of tectonics and climate across the Mesoproterozoic/Neoproterozoic boundary. Rock magnetic experiments on Mamainse Point lavas, paired with electron microscopy, demonstrate that a component of the magnetization in oxidized flows that is antiparallel to the characteristic remanence is a result of martite self-reversal. This component is the best resolved natural example of the experimentally observed self-reversal that accompanies the maghemite to hematite transition. This result allows the magnetizations of the lavas to be fully interpreted, and also suggests that this self-reversal phenomena may be more widespread than currently recognized---with its identification in this study being greatly aided by stratigraphic context during a period when North America was moving rapidly towards the equator. Stratigraphic and stable isotope work on the Neoproterozoic Bitter Springs Formation of the Amadeus Basin demonstrates that the negative carbon isotope values of the "Bitter Springs Stage" are tightly consistent in carbonate rocks across more than 400 km. In addition to being present in the isotopic composition of the carbonate, organic carbon isotope values shift sympathetically into and out of the stage thereby supporting the interpretation that the stage is a record of primary changes to the carbon cycle. The stage is bound by sequence boundaries that provide evidence for changes in sea-level and climate. Previous work on correlative stratigraphy from the Akademikerbreen Group of East Svalbard (Maloof et al., 2006), revealed changes in relative sea-level and paleomagnetic directions that have were interpreted to have resulted from a pair of large-scale true polar wander events. In an effort to further test this hypothesis, and to remedy a lack of paleogeographic constraints for north Australia in the early Neoproterozoic, I present paleomagnetic data from more than 630 paleomagnetic samples of carbonates, siltstones and basalt flows from the Bitter Springs Formation. A new reliable pole from post-Bitter Springs Stage siltstones provides strong support for a recently published hypothesis that there was relative rotation between north and south+west Australia in the late Neoproterozoic (Li and Evans, 2011), and for the long-standing hypothesis that Australia and Laurentia were cotravelers in Rodinia into the mid-Neoproterozoic Era. The difference between the paleomagnetic poles of syn-Bitter Springs Stage carbonates and post-Bitter Springs Stage siltstones is likely a result of a Cambrian remagnetization of

Swanson-Hysell, Nicholas L.

213

Hydrodynamic trapping in the Cretaceous Nahr Umr lower sand of the North Area, Offshore Qatar  

SciTech Connect

A hydrodynamic model is described to account for oil and gas occurrences in the Cretaceous of offshore Qatar, in the Arabian Gulf. Variable and inconsistent fluid levels and variable formation water potentials and salinities cannot be explained by combinations of stratigraphic and structural trapping. Indeed, there is no structural closure to the southwest of the oil and gas accumulations. The water-potential and salinity data and oil distribution are consistent with this model and indicate that a vigorous hydrodynamic system pervades the Cretaceous of the Arabian Gulf region. Extensive upward cross-formational discharge is taking place in the North Area. This cross-formation water flow could be partly responsible for localized leaching and reservoir enhancement in the chalky limestones.

Wells, P.R.A.

1988-03-01

214

An application of numerical simulation techniques to improve the resolution of offshore fault kinematics using seafloor geodetic methods  

NASA Astrophysics Data System (ADS)

Geodetic measurements reveal a number of tectonic phenomena, such as coseismic and postseismic displacements of earthquakes and interplate coupling on plate interfaces. However, since geodetic measurements are limited to land, slip distribution is poorly resolved offshore, though well constrained in the landward areas. Due to the poverty of offshore data, tectonic motion near trench axes has not been measured. Seafloor geodetic observations provide important information on offshore tectonics. Improved offshore resolution would allow determination of strain accumulation and release processes near trench axes. In this study, using numerical simulation, we discuss the potential for improvement of slip resolution in an offshore area using seafloor geodetic measurements. The plate interface along the Nankai trough is modeled by 36 planar fault segments, whose length and width, respectively, are set to 60 km and 50 km. Three hundred and seventy-five GPS observation sites on land and 10 seafloor sites aligned 60 km off the coast are used for the simulation. We carry out a checkerboard test and compare the estimated slip pattern with the given checkerboard pattern. Models that do not include seafloor sites generate large discrepancies in offshore deformation between the initial and estimated slip patterns, although there are similarities in coastal regions. This indicates poor resolution in offshore areas. When we apply our model to include seafloor sites, the difference between the initial and estimated slip patterns decreases for most of the modeled fault segments. Comparison between these two cases suggests the potential for use of seafloor geodetic techniques to improve offshore resolution.

Nishimura, Sou; Ando, Masataka; Tadokoro, Keiichi

2005-08-01

215

Brookian stratigraphic plays in the National Petroleum Reserve - Alaska (NPRA)  

USGS Publications Warehouse

The Brookian megasequence in the National Petroleum Reserve in Alaska (NPRA) includes bottomset and clinoform seismic facies of the Torok Formation (mostly Albian age) and generally coeval, topset seismic facies of the uppermost Torok Formation and the Nanushuk Group. These strata are part of a composite total petroleum system involving hydrocarbons expelled from three stratigraphic intervals of source rocks, the Lower Cretaceous gamma-ray zone (GRZ), the Lower Jurassic Kingak Shale, and the Triassic Shublik Formation. The potential for undiscovered oil and gas resources in the Brookian megasequence in NPRA was assessed by defining five plays (assessment units), one in the topset seismic facies and four in the bottomset-clinoform seismic facies. The Brookian Topset Play is estimated to contain between 60 (95-percent probability) and 465 (5-percent probability) million barrels of technically recoverable oil, with a mean (expected value) of 239 million barrels. The Brookian Topset Play is estimated to contain between 0 (95-percent probability) and 679 (5-percent probability) billion cubic feet of technically recoverable, nonassociated natural gas, with a mean (expected value) of 192 billion cubic feet. The Brookian Clinoform North Play, which extends across northern NPRA, is estimated to contain between 538 (95-percent probability) and 2,257 (5-percent probability) million barrels of technically recoverable oil, with a mean (expected value) of 1,306 million barrels. The Brookian Clinoform North Play is estimated to contain between 0 (95-percent probability) and 1,969 (5-percent probability) billion cubic feet of technically recoverable, nonassociated natural gas, with a mean (expected value) of 674 billion cubic feet. The Brookian Clinoform Central Play, which extends across central NPRA, is estimated to contain between 299 (95-percent probability) and 1,849 (5-percent probability) million barrels of technically recoverable oil, with a mean (expected value) of 973 million barrels. The Brookian Clinoform Central Play is estimated to contain between 1,806 (95-percent probability) and 10,076 (5-percent probability) billion cubic feet of technically recoverable, nonassociated natural gas, with a mean (expected value) of 5,405 billion cubic feet. The Brookian Clinoform South-Shallow Play is estimated to contain between 0 (95-percent probability) and 1,254 (5-percent probability) million barrels of technically recoverable oil, with a mean (expected value) of 508 million barrels. The Brookian Clinoform South-Shallow Play is estimated to contain between 0 (95-percent probability) and 5,809 (5-percent probability) billion cubic feet of technically recoverable, nonassociated natural gas, with a mean (expected value) of 2,405 billion cubic feet. The Brookian Clinoform South-Deep Play is estimated to contain between 0 (95-percent probability) and 8,796 (5-percent probability) billion cubic feet of technically recoverable, nonassociated natural gas, with a mean (expected value) of 3,788 billion cubic feet. No technically recoverable oil is assessed in the Brookian Clinoform South-Deep Play, as it lies at depths that are entirely in the gas window. Among the Brookian stratigraphic plays in NPRA, the Brookian Clinoform North Play and the Brookian Clinoform Central Play are most likely to be objectives of exploration activity in the near-term future because they are estimated to contain multiple oil accumulations larger than 128 million barrels technically recoverable oil, and because some of those accumulations may occur near existing infrastructure in the eastern parts of the plays. The other Brookian stratigraphic plays are not likely to be the focus of exploration activity because they are estimated to contain maximum accumulation sizes that are smaller, but they may be an objective of satellite exploration if infrastructure is extended into the play areas. The total volumes of natural gas estimated to occur in B

Houseknecht, David W.

2003-01-01

216

Coupled Passive Margin Stratigraphic Evolution and Fluid Flow  

NASA Astrophysics Data System (ADS)

Continental margin processes are strongly influenced by patterns of overpressure and fluid flow within basin sediments. These patterns effect consolidation, slope stability, and the transport of heat and solutes. Numerous processes generate overpressure, but in many passive margins rapid deposition is thought to be a dominant mechanism, producing a two-way coupling between sedimentary processes and fluid flow. We study this coupling using a fully 2D margin-scale coupled stratigraphic evolution and fluid flow model. The sedimentary process model describes transport of sand and mud through coastal plain, shoreface, shelf, slope, fan, and rise depositional environments, as well as migration of internal boundaries between environments. The fluid flow model uses the finite element method (FEM) to solve for fluid flow on a dynamic grid. We explore the effects of 2D coupling for various basin geometries, sea-level histories, and sediment influx rates. We find that on a margin-scale, deposition tends to be localized in depocenters, which are initiated by sediment flux divergence across depositional environment boundaries (e.g. shoreline, shelf-break). Over timescales relevant to pore-pressure evolution, these boundaries and their associated clinoforms migrate in response to sedimentation and relative sea level change, resulting in complex dynamic patterns of overpressure. Although in some regions fluid flow is quasi-1D (vertical and forced only by local deposition), in many regions fluid flow is strongly 2D. Complex flow results from heterogeneous stratigraphy, with strong contrasts in sand and mud permeability determining preferential flow paths. On regional scales, confined horizontal sandy units, such as buried turbidite fan complexes, act as fluid flow conduits, inducing flow anisotropy. On smaller scales, interbedded sandy and muddy deposits produce anisotropic effective permeabilities with preferential horizontal flow. The complex dynamic geometries inherent to margin stratigraphic evolution have heretofore prevented effective margin-scale modeling coupled 2D stratigraphic-hydrologic system, but our computational approach introduces two innovations. A dynamic meshing technique allows for rapid meshing of arbitrary deposits while maintaining bounds on FEM conditioning and error. And a hierarchical mesh structure, which aggregates sediment layers into mesh nodes into finite elements, embeds sub-grid dynamics into the FEM model via layer averaged anisotropic permeabilities. Our results show that in regions of homogeneous lithology, quasi-1D numerical or asymptotic approximations are applicable, but that in regions with complex stratigraphy, strong anisotropy effects cannot be ignored. Our meshing and FEM approach is general and easily adapted for use with any sedimentary or backstripping model, and models including more grain sizes or processes have an even greater potential for complex 2D fluid flow. Hence our results demonstrate the viability and necessity of including 2D effects in continental margin fluid flow models.

Wolinsky, M. A.; Pratson, L. F.

2004-12-01

217

Stratigraphic variations in oil-shale fracture properties. [Colorado and Wyoming  

SciTech Connect

The proper design and evaluation of in situ oil shale fracture and retorting experiments require that both the extreme values and spatial distribution of the controlling rock properties be adequately known. Many of the in situ technologies being considered for processing within the Green River Formation in Colorado, Wyoming and Utah depend upon the carefully controlled explosive fracturing of the rock such that suitably uniform permeabilities are achieved. The prediction, control and evaluation of explosive oil shale fracturing require a detailed knowledge of tensile strength behavior as a function of shale grade and stratigraphic position. Direct-pull tensile tests, point-load pinch tests, and four-point-bend fracture toughness tests have been utilized to develop detailed logs of the relevant fracture properties for the 37 m thick Mahogany Zone section of the Green River Formation near Anvil Points, Colorado and for the rich, upper 13 m of the Tipton Member near Rock Springs, Wyoming. For the Mahogany Zone shale tensile strengths ranged up to 15.3 MPa for direct-pull tests and 43.4 MPa for indirect tests. Fracture energy values for this shale ranged from 8 J/m/sup 2/ to 191 J/m/sup 2/. For the Tipton shale tensile strengths ranged up to 3.7 MPa for direct-pull tests and 12.6 MPa for indirect tests. Fracture energy values for the Tipton averaged from 5 J/m/sup 2/ to 91 J/m/sup 2/. Detailed statistical analyses were performed on these data and on Fischer assay oil yield data to establish the correlations between them. Data from both tensile strength and fracture energy tests correlate well with lithologic and oil yield characteristics of the Mahogany Zone shale while poor correlations were found for the Tipton shale. 27 figures, 8 tables.

Young, C.; Patti, N. C.; Trent, B. C.

1982-09-01

218

Tephrochronology offshore Ischia Island, Tyrrhenian sea, Italy  

NASA Astrophysics Data System (ADS)

This work presents the analytical results of a tephrochronological study carried out on 12 gravity cores collected offshore southern Ischia island down to a maximum depth of 1238 m. The more distal site (core C1071) is located few kilometers to the west of the "Banco delle Sirene" seamount, not far from the Magnaghi and Dohrn canyons. The composite succession records at least the last ca. 40 kyrs of marine sedimentation as deduced by 14C AMS dating and tephrostratigraphy. This is consistent with the attribution, on the basis of the calcareous nannofossil assemblages, to the Emiliania huxleyi Acme Zone (Rio et al., 1990) in the latest Pleistocene-Holocene time interval. Eight primary tephra layers were recognised and analysed. They are generally represented by coarse to fine ash alternating with a number of volcaniclastic turbidites along the whole succession. The glass fraction was geochemically characterised through SEM-EDS analyses and shows clear affinities with products erupted during significant explosive events occurred in the Campania Plain, Ischia and Procida islands during the last 40 kyrs. Four ash layers were correlated with several eruptions occurred on Ischia island between the Middle Ages and Roman times and at ~ cal. 17 ka B.P. Deposits related to explosive activity occurred on Procida island were also found and dated at ~23 cal ka. Among the most ancient tephra layers, the best preserved horizon, 30 cm thick, is represented by the flegrean products of the Campanian Ignimbrite event (39 ka; De Vivo et al., 2001) the marine signature of which is known as C13 tephra in the Tyrrhenian (Thon-That et al., 2001). The peculiar composition and stratigraphic position of two other main marker tephras recognised in the succession, allowed us to correlate them with the still poorly known Schiava (36 ka B.P.; Paterne and Guichard, 1993; Sulpizio et al., 2003) and Codola (~33. cal ka B.P.; this work) fall-out products which occur as 7-5 cm-thick pumice layers at the coring site. The definition of the source area of these two major events is still a matter of debate. However, the Somma-Vesuvius complex reasonably sourced the Schiava deposits while a Campi Flegrei provenance for the Codola deposits cannot be ruled out (Di Vito et al., 2008). These latters, known as C10 tephra in the Tyrrhenian and Adriatic sea (Paterne et al., 1988; Giaccio et al., 2008), in particular, represent reliable regional markers for the whole central Mediterranean area. References De Vivo, B., Rolandi, G., Gans, P.B., Calvert, A., Bohrson,W.A., Spera, F.J., Belkin, H.E., 2001. New constraints on the pyroclastic eruptive history of the Campanian volcanic Plain (Italy). Mineralogy and Petrology 73, 47-65. Di Vito,M.A., Sulpizio, R., Zanchetta, G., D'Orazio, M., 2008. The late Pleistocene pyroclastic deposits of the Campanian Plain: newinsights into the explosive activity of Neapolitan volcanoes. J. Volcanol. Geotherm. Res.177, 19-48. Giaccio, B., Isaia, R., Fedele, F.G., Di Canzio, E., Hoffecker, J., Ronchitelli, A., Sinitsyn, A., Anikovich, M., Lisitsyn, S.N., 2008. The Campanian Ignimbrite and Codola tephra layers: two temporal/stratigraphic markers for the Early Upper Palaeloithic in southern Italy and eastern Europe. J. Volcanol. Geotherm. Res. 177, 210-228. Paterne M., Guichard F. & Labeyrie J., 1988. Explosive activity of the south Italian volcanoes during the past 80.000 years as determined by marine tephrochronology. J. Volcanol. Geother. Res. 34, 153-172. Paterne, M., Guichard, F., 1993. Triggering of volcanic pluses in the Campanian area, south Italy, by periodic deep magma in.ux. Journal of Geophysical Research 98 (B2), 1861-1873. Rio, D., Raffi, I., Villa, G., 1990. Pliocene-Pleistocene calcareous nannofossil distribution patterns in the western Mediterranean. In: Kastens, K.A. (Ed.), Proceedings of the Ocean Drilling Program. Scientific Results, vol. 107. Ocean Drilling Program, College Station, TX, pp. 513-533. Sulpizio, R., Zanchetta, G., Paterne, M., Siani, G., 2003. A review of tephrostratigraphy in central and south

Insinga, Donatella; Sulpizio, Roberto; de Alteriis, Giovanni; Morabito, Simona; Morra, Vincenzo; Sprovieri, Mario; di Benedetto, Claudia; Lubritto, Carmine; Zanchetta, Giovanni

2010-05-01

219

The offshore petroleum industry: The formative years, 1945-1962  

NASA Astrophysics Data System (ADS)

This dissertation is the first to examine the offshore oil industry that was born in the calm waters of the Gulf of Mexico. It describes the industry's origins and tracks its development as a consequence of a search for new oil frontiers. In addition, it elaborates how the oil industry moved into the marine province using available technology, and was driven by the economic urgency to compete and develop new territories. Enterprising drilling contractors and operators seized the offshore gamble, finding it possible to lower the economic and technological threshold by drawing directly from wartime research and surplus equipment. Though large oil companies had placed its indelible stamp upon the industry, the smaller, independent oil operators set the pace of early offshore development. As a technological frontier, offshore development depended upon creative and unconventional engineering. Unfamiliar marine conditions tested the imagination of oil industry engineering. The unorthodox methods of John Hayward of Barnsdall Oil and R. G. LeTourneau of LeTourneau, Inc. among others transformed the industry by blending petroleum and marine engineering. Grappling with alien marine conditions and lacking formal training, Hayward and LeTourneau merged a century of practical oil field knowledge and petroleum engineering with 2,000 years of shipbuilding experience. The Gulf of Mexico served as a fertile and protective environment for the development of a fledgling industry. With calm waters, lacking the tempestuous and stormy character of the Atlantic Ocean, with a gradual sea-floor slope and saturated with the highly productive salt dome reservoirs, the Gulf became the birth place of the modern offshore oil industry. Within its protective sphere, companies experimented and developed various technical and business adaptations. Operators used technology and business strategies that increased the opportunity for success. In addition, regional academic research institutes arose as a response to increasing work done for the offshore industry. Academic areas that developed included oceanography, physical oceanography, marine biology, marine geology, meteorology, and weather forecasting, During the formative era that ended in the late 1950s the industry had formed its technological and economic foundation in the Gulf, and stood poised to seize the initiative in the North Sea, the Middle East, the Far East, and Indonesia.

Kreidler, Tai Deckner

1997-12-01

220

Offshore drilling, construction: Fortunes tied to stable gas prices  

Microsoft Academic Search

Significantly improved US natural gas prices fueled an upswing in offshore drilling in the Gulf of Mexico in late 1992. Stabilized gas prices will be necessary to support both the off-shore drilling and construction markets in 1993 and beyond. The article discusses both these segments in detail: offshore drilling and offshore construction.

S. S. Pagano; T. Marsh

1993-01-01

221

An Economic Evaluation Method of Offshore Drilling Platform Overhaul Projects  

Microsoft Academic Search

The stable and efficient operation of offshore drilling platform is the prerequisite that enable success of offshore petroleum exploration and development activities. Offshore drilling platforms are often required periodical overhaul to restore its operational capacity after long time use in the marine environment. However, not all offshore drilling platform overhaul projects are economically feasible. In order to determine the economic

Luo Dong-kun; Dai You-jin

2009-01-01

222

Quantifying the hurricane risk to offshore wind turbines  

E-print Network

Quantifying the hurricane risk to offshore wind turbines Stephen Rosea , Paulina Jaramilloa,1 GW will be required from shallow offshore turbines. Hurricanes are a potential risk to these turbines be destroyed by hurricanes in an offshore wind farm. We apply this model to estimate the risk to offshore wind

Jaramillo, Paulina

223

Offshore drilling to increase in 1984  

SciTech Connect

A mid-year report presents a worldwide overview of offshore drilling operations. The Gulf of Mexico and the North Sea are posting substantial gains as companies rush to drill the millions of acres acquired in those sectors both last year and in previous offerings. The Middle East, Latin America and the Asia/Pacific offshore theaters will see only slight increases. The Mediterranean and African regions are expected to sustain declines. A region-by-region summary of the 1984 offshore forecast is presented showing exploration and appraisal activities, as well as development for all of these areas.

Not Available

1984-05-01

224

Basal Murphy belt and Chilhowee Group -- Sequence stratigraphic comparison  

SciTech Connect

The lower Murphy belt in the central western Blue Ridge is interpreted to be correlative to the Early Cambrian Chilhowee Group of the westernmost Blue Ridge and Appalachian fold and thrust belt. Basal Murphy belt depositional sequence stratigraphy represents a second-order, type-2 transgressive systems tract initiated with deposition of lowstand turbidites of the Dean Formation. These transgressive deposits of the Nantahala and Brasstown Formations are interpreted as middle to outer continental shelf deposits. Cyclic and stacked third-order regressive, coarsening upwards sequences of the Nantahala Formation display an overall increase in feldspar content stratigraphically upsection. These transgressive siliciclastic deposits are interpreted to be conformably overlain by a carbonate highstand systems tract of the Murphy Marble. Palinspastic reconstruction indicates that the Nantahala and Brasstown Formations possibly represent a basinward extension of up to 3 km thick siliciclastic wedge. The wedge tapers to the southwest along the strike of the Murphy belt at 10[degree] and thins northwestward to 2 km in the Tennessee depocenter where it is represented by the Chilhowee Group. The Murphy belt basin is believed to represent a transitional rift-to-drift facies deposited on the lower plate of the southern Blue Ridge rift zone.

Aylor, J.G. Jr. (Florida State Univ., Tallahassee, FL (United States). Dept. of Geology)

1994-03-01

225

Horizontal drilling in the Austin Chalk: Stratigraphic factors  

SciTech Connect

Horizontal drilling has renewed interest in the Austin chalk in south-central Texas. Large fields on opposite sides of the San Marcos arch Giddings to the northeast and Pearsall to the southwest were active with vertical drilling 10 years ago. Giddings' 4,500 Austin wells produced 209 million BO and 934 bcfg of gas through 1988; Pearsall's 1,440 wells produced 57 million BO and 35 bcfg of gas. Most vertical wells were completed, 20% were economic successes, 40% were marginal, 40% were uneconomic due to uneven areal distribution of near-vertical fractures and small faults, which provide reservoirs in otherwise tight chalk. Horizontal drilling, led by Amoco in Giddings and Oryx in Pearsall, enhances the chances of encountering the fractures by drilling perpendicular to the fracture trend. Horizontal drilling requires preselection of the stratigraphic horizon to be penetrated. One must understand the variable Austin stratigraphy to choose the zone with the most brittle character and best matrix porosity, both reduced by increased clay content. Chalk 130 ft thick on the San Marcos arch thickens to 600 to 800 ft in central Giddings field where middle marl separates lower and upper chalk Northeastward only lower chalk is preserved beneath a post-Austin submarine channel. The Austin thickens to 300-500 ft in Pearsall field where middle member ash beds separate lower and upper chalk inhibiting vertical reservoir communication. Locally, on the Pearsall arch, ash is missing, lower chalk thickens, and upper chalk thins.

Durham, C.O. Jr. (Durham Geological Associates, Houston, TX (USA)); Bobigian, R.A. (Fleet Petroleum Partners, Houston, TX (USA))

1990-05-01

226

Pleistocene sediments of Lake Baikal: Lithology and stratigraphic correlation  

NASA Astrophysics Data System (ADS)

The Cenozoic sediments of Lake Baikal penetrated by boreholes and investigated by the manned submersible Pisces, as well as coeval deposits cropping out in beach scarps, recovered by mine workings, and drilled in the coastal zone were the object of this investigation. The main attention was paid to Pleistocene bottom sediments penetrated by Borehole BDP-99-2. The investigations included the detailed analysis of the lithology (grain-size composition, immersion mineralogy of light and heavy fractions, X-ray structural analysis of clayey fraction) and palynological assemblages to specify facies features of Cenozoic sediments, correlate all their known stratigraphic units constituting the sedimentary section of the lake with their analogs in the onshore part of the Baikal rift zone, and compile the composite Cenozoic section. The following features of these sediments are noted: (1) as a whole, Pleistocene sediments are characterized by the hydromica-smectite composition of their clayey fraction with an insignificant share of kaoline; (2) the heavy fraction is dominated by the terrigenous epidote-amphibole association poorly resistant to weathering; (3) Pleistocene sediments of the lake contain siderite, vivianite, pyrite, and goethite concretions and micrometeorites, in addition to well-known ferromanganese nodules; (4) the presence of relict palynomorphs in Pleistocene sediments of Baikal is determined by their erosion from Miocene and Pliocene cavernous clays cropping out on underwater slopes of the Posol'skaya Bank and subsequent reburial along with Pleistocene palynological assemblages.

Akulov, N. I.; Mashchuk, I. M.; Akulova, V. V.

2015-01-01

227

Eolian paleotopographic highs as stratigraphic traps: origin and distinction  

SciTech Connect

Significant hydrocarbon accumulations occur where eolian paleotopographic highs are preserved beneath transgressive marine deposits. Paleotopographic highs can represent erosional remnants of an unconformity, or partly preserved eolian dunes, or combinations of both. Paleotopography reflects the extent of modification undergone by eolian units prior to or during transgression. Modification varies between extremes of (1) destruction - where eolian deposits are deeply eroded and the former dunal profile is lost, and (2) preservation - where dunes and interdune areas are preserved nearly intact. The extent of modification that occurs during transgression is controlled primarily by (1) the energy of the transgressing sea, (2) the speed of transgression, and (3) the abundance of sand-stabilizing early cements or plants. High-energy seas destroy dunes through persistent erosion by tides and waves and by initiating dune collapse and mass flowage of dune sands. Preservation occurs where quiescent seas flood interdune areas and create shallow to periodically emergent marine environments, such as interdune sabkhas or tidal flats. Gradual filling of interdune areas with shallow marine sediments can fortify and preserve adjacent dunes. These varied processes that interact between marine and eolian environments to create different types of topography are exemplified in ancient eolian-marine sequences of the Western Interior of North America, and preserved Holocene dunes of coastal Australia. Different types of eolian highs can be recognized by analysis of bounding surfaces in outcrop or core. An understanding of eolian-marine processes and environments that create topography allows for prediction of areas of potential stratigraphic traps.

Eschner, T.B.; Kocurek, G.A.

1985-02-01

228

The oligocene stratigraphic framework of the coastal plain of the southeastern United States  

SciTech Connect

Four lithostratigraphic associations are recognized in the Oligocene of the southeastern Coastal Plain: (1) an eastern Gulf of Mexico stratigraphic association, (2) a Gulf Trough stratigraphic association, (3) a Florida Bank stratigraphic association and (4), an Atlantic continental shelf stratigraphic association. Oligocene formations and faunal provinces appear to be directly related to the stratigraphic associations. The Vicksburg Group is restricted to the eastern Gulf of Mexico continental shelf stratigraphic association and to the Coastal Plain north and west of the Gulf Trough. The Gulf Trough stratigraphic association includes the Ochlockonee Formation, Wolf Pit Dolostone, Okapilco Limestone, and Bridgeboro Limestone (the Bridgeboro Limestones occurs only on and adjacent to the northern and southern flanks of the trough). The Florida Bank stratigraphic association is largely restricted to the area south of the Gulf Trough and includes the Ellaville Limestone, Suwannacoochee Dolostone, and Suwannee Limestone (the Suwannee Limestone also occurs immediately north of the Gulf Trough in the central Georgia Coastal Plain). The Cooper and Lazaretto Creek Formations are restricted to the Atlantic continental shelf stratigraphic association and occur only in the coastal area of Georgia, South Carolina, and beneath the continental shelf. Three faunal provinces (or subprovinces) are recognized in the southeastern Coastal Plain during the Oligocene: (1) a Gulf of Mexico continental shelf faunal province that characterizes the Gulf Trough and the region north and west of the trough, (2) a Florida province characteristic and largely restricted to the Florida Bank and (3), an Atlantic continental shelf faunal province. Through the Early Oligocene, the trough marked the limits of the Gulf of Mexico and Florida provinces.

Huddlestun, P.F. (Georgia Geologic Survey, Atlanta, GA (United States))

1993-03-01

229

Late Pleistocene stratigraphy of IODP Site U1396 and compiled chronology offshore of south and south west Montserrat, Lesser Antilles  

NASA Astrophysics Data System (ADS)

sediments around volcanic islands contain an archive of volcaniclastic deposits, which can be used to reconstruct the volcanic history of an area. Such records hold many advantages over often incomplete terrestrial data sets. This includes the potential for precise and continuous dating of intervening sediment packages, which allow a correlatable and temporally constrained stratigraphic framework to be constructed across multiple marine sediment cores. Here we discuss a marine record of eruptive and mass-wasting events spanning ˜250 ka offshore of Montserrat, using new data from IODP Expedition 340, as well as previously collected cores. By using a combination of high-resolution oxygen isotope stratigraphy, AMS radiocarbon dating, biostratigraphy of foraminifera and calcareous nannofossils, and clast componentry, we identify five major events at Soufriere Hills volcano since 250 ka. Lateral correlations of these events across sediment cores collected offshore of the south and south west of Montserrat have improved our understanding of the timing, extent and associations between events in this area. Correlations reveal that powerful and potentially erosive density-currents traveled at least 33 km offshore and demonstrate that marine deposits, produced by eruption-fed and mass-wasting events on volcanic islands, are heterogeneous in their spatial distribution. Thus, multiple drilling/coring sites are needed to reconstruct the full chronostratigraphy of volcanic islands. This multidisciplinary study will be vital to interpreting the chaotic records of submarine landslides at other sites drilled during Expedition 340 and provides a framework that can be applied to the stratigraphic analysis of sediments surrounding other volcanic islands.

Wall-Palmer, Deborah; Coussens, Maya; Talling, Peter J.; Jutzeler, Martin; Cassidy, Michael; Marchant, Isabelle; Palmer, Martin R.; Watt, Sebastian F. L.; Smart, Christopher W.; Fisher, Jodie K.; Hart, Malcolm B.; Fraass, Andrew; Trofimovs, Jessica; Le Friant, Anne; Ishizuka, Osamu; Adachi, Tatsuya; Aljahdali, Mohammed; Boudon, Georges; Breitkreuz, Christoph; Endo, Daisuke; Fujinawa, Akihiko; Hatfield, Robert; Hornbach, Matthew J.; Kataoka, Kyoko; Lafuerza, Sara; Maeno, Fukashi; Manga, Michael; Martinez-Colon, Michael; McCanta, Molly; Morgan, Sally; Saito, Takeshi; Slagle, Angela L.; Stinton, Adam J.; Subramanyam, K. S. V.; Tamura, Yoshihiko; Villemant, Benoit; Wang, Fei

2014-07-01

230

Depositional model and stratigraphic architecture of rift climax Gilbert-type fan deltas (Gulf of Corinth, Greece)  

NASA Astrophysics Data System (ADS)

Facies, depositional model and stratigraphic architecture of Pleistocene giant Gilbert-type fan deltas are presented, based on outcrop data from the Derveni-Akrata region along the southern coast of the Gulf of Corinth, Greece. The common tripartite consisting of topset, foreset and bottomset [Gilbert, G.K., 1885. The topographic features of lake shores: Washington, D.C., United States Geol. Survey, 5th Annual Report, 69-123.] has been identified, as well as the most distal environment consisting of turbidites, and is organised in a repetitive pattern of four main systems tracts showing a clear facies and volumetric partitioning. The first systems tract (ST1) is characterised by the lack of topset beds and the development of a by-pass surface instead, thick foresets and bottomset beds, and thick well-developed turbiditic systems. This systems tract (ST1) is organised in an overall progradational pattern. The second systems tract (ST2) is characterised by a thin topset and almost no foreset equivalent. This systems tract is not always well-preserved and is organised in an overall retrograding trend with a landward shift in the position of the offlap break. The offshore is characterised by massive sandy turbidites. The third systems tract (ST3) is characterised by small-scale deltas prograding above the staked topsets of the giant Gilbert-type fan delta. Those small Gilbert-type fan deltas are generally organised in a pure progradation evolving to an aggradational-progradational pattern. In the distal setting of those small Gilbert-type fan deltas, almost no deposits are preserved on the remaining topography of the previous Gilbert-type fan delta. The fourth systems tract (ST4) is characterised by continuous vertically aggrading topsets that laterally pass into aggrading and prograding foresets. Bottomsets and distal turbiditic systems are starved. This fourth systems tract (ST4) is organised in an overall aggrading trend. These giant Gilbert-type fan deltas correspond to the Middle Group of the Corinth Rift infill and their stratigraphic development was strongly influenced by evolving rift structure. They record the migration of the depocenter from the rift shoulder to the rift axis in four main sequences from ca. 1.5 to 0.7 Ma, related to the migration of fault activity. It is worth noting that the maximum paleobathymetry was recorded during the final stage of the progradation of the Middle Group, suggesting that the rift climax was diachronous at the scale of the entire basin. The rapid (< 1 Ma) structural and sedimentological evolution, the migration of fault activity as well as the youth of the Corinth Rift, are probably exceptional factors allowing the characterisation of such diachronism.

Rohais, Sébastien; Eschard, Rémi; Guillocheau, François

2008-10-01

231

31 CFR 576.407 - Offshore transactions.  

Code of Federal Regulations, 2013 CFR

...Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRAQ STABILIZATION AND INSURGENCY SANCTIONS REGULATIONS Interpretations § 576.407 Offshore transactions. The...

2013-07-01

232

31 CFR 576.407 - Offshore transactions.  

Code of Federal Regulations, 2014 CFR

...Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRAQ STABILIZATION AND INSURGENCY SANCTIONS REGULATIONS Interpretations § 576.407 Offshore transactions. The...

2014-07-01

233

31 CFR 576.407 - Offshore transactions.  

Code of Federal Regulations, 2012 CFR

...Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRAQ STABILIZATION AND INSURGENCY SANCTIONS REGULATIONS Interpretations § 576.407 Offshore transactions. The...

2012-07-01

234

31 CFR 576.407 - Offshore transactions.  

Code of Federal Regulations, 2011 CFR

...Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRAQ STABILIZATION AND INSURGENCY SANCTIONS REGULATIONS Interpretations § 576.407 Offshore transactions. The...

2011-07-01

235

Offshore oil in the Alaskan Arctic  

NASA Technical Reports Server (NTRS)

Oil and gas deposits in the Alaskan Arctic are estimated to contain up to 40 percent of the remaining undiscovered crude oil and oil-equivalent natural gas within U.S. jurisdiction. Most (65 to 70 percent) of these estimated reserves are believed to occuur offshore beneath the shallow, ice-covered seas of the Alaskan continental shelf. Offshore recovery operations for such areas are far from routine, with the primary problems associated with the presence of ice. Some problems that must be resolved if efficient, cost-effective, environmentally safe, year-round offshore production is to be achieved include the accurate estimation of ice forces on offshore structures, the proper placement of pipelines beneath ice-produced gouges in the sea floor, and the cleanup of oil spills in pack ice areas.

Weeks, W. F.; Weller, G.

1984-01-01

236

31 CFR 541.406 - Offshore transactions.  

Code of Federal Regulations, 2010 CFR

... Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ZIMBABWE SANCTIONS REGULATIONS Interpretations § 541.406 Offshore transactions. The prohibitions in § 541.201 on...

2010-07-01

237

Embedded knowledge and offshore software development  

E-print Network

on evidence from a longitudinal case study of a British software company with an offshore subsidiary in India of Accounting and Finance, University of Manchester, Mezzanine Floor, Crawford House, Booth Street East

Sahay, Sundeep

238

EMS offshore. A new horizon for paramedics.  

PubMed

The difficulty in getting medical aid to offshore drilling platforms can be a source of life-threatening delays. Recently, some companies have charted new waters by actually stationing EMS crews on their rigs. PMID:10116023

Mallard, A S

1991-10-01

239

31 CFR 586.407 - Offshore transactions.  

Code of Federal Regulations, 2010 CFR

...Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FEDERAL REPUBLIC OF YUGOSLAVIA (SERBIA & MONTENEGRO) KOSOVO SANCTIONS REGULATIONS Interpretations § 586.407 Offshore transactions. (a) The prohibitions contained...

2010-07-01

240

Outsourcing, offshoring and the US office market  

E-print Network

There is intense debate among industry analysts and scholars over potential job losses caused by offshoring. The real estate industry has been grappling to understanding the implications of these numbers, as some have ...

Topolewski, Tanya M., 1969-

2004-01-01

241

Visualization of vibration experienced in offshore platforms  

E-print Network

In this thesis, I design and evaluate methods to optimize the visualization of vortex-induced vibration (VIV) in marine risers. VIV is vibration experienced by marine risers in offshore drilling platforms due to ocean ...

Patrikalakis, Alexander Marinos Charles

2010-01-01

242

System architecture of offshore oil production systems  

E-print Network

This thesis presents an approach to applying Systems Architecture methods to the development of large, complex, commercial systems, particularly offshore oil and gas productions systems. The aim of this research was to ...

Keller, James (James Thomas)

2008-01-01

243

31 CFR 541.406 - Offshore transactions.  

Code of Federal Regulations, 2012 CFR

... Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ZIMBABWE SANCTIONS REGULATIONS Interpretations § 541.406 Offshore transactions. The prohibitions in § 541.201 on...

2012-07-01

244

31 CFR 541.406 - Offshore transactions.  

Code of Federal Regulations, 2011 CFR

... Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ZIMBABWE SANCTIONS REGULATIONS Interpretations § 541.406 Offshore transactions. The prohibitions in § 541.201 on...

2011-07-01

245

31 CFR 541.406 - Offshore transactions.  

Code of Federal Regulations, 2013 CFR

... Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ZIMBABWE SANCTIONS REGULATIONS Interpretations § 541.406 Offshore transactions. The prohibitions in § 541.201 on...

2013-07-01

246

31 CFR 541.406 - Offshore transactions.  

Code of Federal Regulations, 2014 CFR

... Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ZIMBABWE SANCTIONS REGULATIONS Interpretations § 541.406 Offshore transactions. The prohibitions in § 541.201 on...

2014-07-01

247

31 CFR 544.406 - Offshore transactions.  

Code of Federal Regulations, 2014 CFR

...Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY WEAPONS OF MASS DESTRUCTION PROLIFERATORS SANCTIONS REGULATIONS Interpretations § 544.406 Offshore transactions. The...

2014-07-01

248

31 CFR 544.406 - Offshore transactions.  

Code of Federal Regulations, 2010 CFR

...Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY WEAPONS OF MASS DESTRUCTION PROLIFERATORS SANCTIONS REGULATIONS Interpretations § 544.406 Offshore transactions. The...

2010-07-01

249

31 CFR 544.406 - Offshore transactions.  

Code of Federal Regulations, 2013 CFR

...Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY WEAPONS OF MASS DESTRUCTION PROLIFERATORS SANCTIONS REGULATIONS Interpretations § 544.406 Offshore transactions. The...

2013-07-01

250

31 CFR 544.406 - Offshore transactions.  

Code of Federal Regulations, 2012 CFR

...Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY WEAPONS OF MASS DESTRUCTION PROLIFERATORS SANCTIONS REGULATIONS Interpretations § 544.406 Offshore transactions. The...

2012-07-01

251

31 CFR 544.406 - Offshore transactions.  

Code of Federal Regulations, 2011 CFR

...Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY WEAPONS OF MASS DESTRUCTION PROLIFERATORS SANCTIONS REGULATIONS Interpretations § 544.406 Offshore transactions. The...

2011-07-01

252

New perspectives in offshore wind energy.  

PubMed

The design of offshore wind turbines is one of the most fascinating challenges in renewable energy. Meeting the objective of increasing power production with reduced installation and maintenance costs requires a multi-disciplinary approach, bringing together expertise in different fields of engineering. The purpose of this theme issue is to offer a broad perspective on some crucial aspects of offshore wind turbines design, discussing the state of the art and presenting recent theoretical and experimental studies. PMID:25583869

Failla, Giuseppe; Arena, Felice

2015-02-28

253

New perspectives in offshore wind energy  

PubMed Central

The design of offshore wind turbines is one of the most fascinating challenges in renewable energy. Meeting the objective of increasing power production with reduced installation and maintenance costs requires a multi-disciplinary approach, bringing together expertise in different fields of engineering. The purpose of this theme issue is to offer a broad perspective on some crucial aspects of offshore wind turbines design, discussing the state of the art and presenting recent theoretical and experimental studies. PMID:25583869

Failla, Giuseppe; Arena, Felice

2015-01-01

254

Seismic definition of Lower Cretaceous delta, south Whale subbasin, offshore Newfoundland  

SciTech Connect

Recognition of stratigraphic traps in areas where previous prospects were structural is a trend attributable partly to the availability of new, high-quality seismic data. In the South Whale subbasin, offshore Newfoundland, Canada, such a change in exploration philosophy is presently being evaluated. Exploratory drilling offshore eastern Canada began in 1966 in the South Whale subbasin. By the end of 1973, 13 wells were drilled in this subbasin; however, lack of success discouraged further drilling. These wells evaluated large, salt-related structures, well defined by seismic data. Although an adequate reservoir was encountered in a number of these wells, faulting associated with halokinesis may have resulted in petroleum migration out of the reservoir. Interpretation of recently acquired high-quality seismic data indicate a delta in the Lower Cretaceous Missisauga Formation in the study area. Seismic dip sections across the delta show a shingled progradation pattern suggesting a wave-dominated depositional environment. The delta comprises approximately 400 km/sup 2/, with closure in the eastern half. Data from wells in the area indicate that adequate source and sealing beds could be present. Furthermore, rocks of similar age in the nearby Avalon basin contain significant petroleum accumulations, the most notable being within the Hibernia oil field.

Jayasinghe, N.R.; Stokes, R.E.

1986-05-01

255

46 CFR 11.470 - Officer endorsements as offshore installation manager.  

Code of Federal Regulations, 2010 CFR

...endorsements as offshore installation manager. 11.470...endorsements as offshore installation manager. (a...endorsements as offshore installation manager (OIM) include... (i) Provides a description of the...

2010-10-01

256

Neogene sequence stratigraphy, Nam Con Son Basin, offshore Vietnam  

SciTech Connect

An integrated well log, biostratigraphic, and seismic stratigraphic study of Miocene to Recent deltaic sediments deposited in the Nam Con Son Basin offshore from southern Vietnam shows the influence of eustacy and tectonics on sequence development. Sediments consist of Oligocene non-marine rift-basin fill (Cau Formation), early to middle Miocene tide-dominated delta plain to delta front sediments (TB 1.5 to TB 2.5, Due and Thong Formations), and late Miocene to Recent marine shelf sediments (TB. 2.6 to TB 3.1 0, Mang Cau, Nam Con Son, and Bien Dong Formations). Eustacy controlled the timing of key surfaces and sand distribution in the tectonically-quiet early Miocene. Tectonic effects on middle to late Miocene sequence development consist of thick transgressive systems tracts due to basin-wide subsidence and transgression, sand distribution in the basin center, and carbonate sedimentation on isolated fault blocks within the basin. Third-order sequence boundaries (SB) are identified by spore peaks, sand stacking patterns, and channel incision. In the basin center, widespread shale beds with coal occur above sequence boundaries followed by transgressive sandstone units. These TST sandstones merge toward the basin margin where they lie on older HST sandstones. Maximum flooding surfaces (MFS) have abundant marine microfossils and mangrove pollen, a change in sand stacking pattern, and often a strong seismic reflection with downlap. Fourth-order genetic-type sequences are also interpreted. The MFS is the easiest marker to identify and correlate on well logs. Fourth-order SB occur within these genetic units but are harder to identify and correlate.

McMillen, K.J. (Beaver Creek Tech. Co., Mason, TX (United States)); Do Van Luu; Lee, E.K.; Hong, S.S. (PEDCO, Ho Chi Minh City (Viet Nam))

1996-01-01

257

Neogene sequence stratigraphy, Nam Con Son Basin, offshore Vietnam  

SciTech Connect

An integrated well log, biostratigraphic, and seismic stratigraphic study of Miocene to Recent deltaic sediments deposited in the Nam Con Son Basin offshore from southern Vietnam shows the influence of eustacy and tectonics on sequence development. Sediments consist of Oligocene non-marine rift-basin fill (Cau Formation), early to middle Miocene tide-dominated delta plain to delta front sediments (TB 1.5 to TB 2.5, Due and Thong Formations), and late Miocene to Recent marine shelf sediments (TB. 2.6 to TB 3.1 0, Mang Cau, Nam Con Son, and Bien Dong Formations). Eustacy controlled the timing of key surfaces and sand distribution in the tectonically-quiet early Miocene. Tectonic effects on middle to late Miocene sequence development consist of thick transgressive systems tracts due to basin-wide subsidence and transgression, sand distribution in the basin center, and carbonate sedimentation on isolated fault blocks within the basin. Third-order sequence boundaries (SB) are identified by spore peaks, sand stacking patterns, and channel incision. In the basin center, widespread shale beds with coal occur above sequence boundaries followed by transgressive sandstone units. These TST sandstones merge toward the basin margin where they lie on older HST sandstones. Maximum flooding surfaces (MFS) have abundant marine microfossils and mangrove pollen, a change in sand stacking pattern, and often a strong seismic reflection with downlap. Fourth-order genetic-type sequences are also interpreted. The MFS is the easiest marker to identify and correlate on well logs. Fourth-order SB occur within these genetic units but are harder to identify and correlate.

McMillen, K.J. [Beaver Creek Tech. Co., Mason, TX (United States); Do Van Luu; Lee, E.K.; Hong, S.S. [PEDCO, Ho Chi Minh City (Viet Nam)

1996-12-31

258

Stratigraphic traps for petroleum in wind-laid rocks  

SciTech Connect

Three major kinds of stratigraphic traps for petroleum exist in wind-deposited rocks: geomorphic, diagenetic, and system-boundary traps. Geomorphic petroleum traps are those in which oil is trapped in association with preserved topographic relief on eolian sands. The preserved relief may be inherited from the original dune field, modified by reworking, or created by erosion of dune sandstones prior to burial by the next layer of sediments. Diagenetic traps for petroleum are those in which oil is trapped by lateral changes in porosity and permeability within the wind-laid rocks. Usually, oil is trapped against cemented zones, which may be selective or nonselective of depositional facies. The propensity of eolian deposits to have diagenetic traps may be due to early cementation, reflecting the common association of desert dunes and evaporites. Traps for petroleum may also be created by decementation - typically the dissolution of early halite, gypsum, or anhydrite. System-boundary traps for petroleum are those in which oil is trapped at the updip depositional edge of the eolian-system deposits, where they intertongue with impermeable sediments of a different depositional environment. System-boundary traps can be sharp or diffuse. Sharp system-boundary traps can create or help create large single pools, such as the 1.6 billion bbl pool at Rangely oil field, Colorado. Diffuse system-boundary traps may contain as much oil as sharp system-boundary traps, but the oil is spread over a much wider area in a multitude of smaller pools, as in the Minnelusa Formation of northeast Wyoming. 17 figures.

Fryberger, S.G.

1986-12-01

259

Sequence stratigraphic controls on synsedimentary cementation and preservation of dinosaur tracks: Example from the lower Cretaceous,  

E-print Network

Sequence stratigraphic controls on synsedimentary cementation and preservation of dinosaur tracks in the Upper Albian Dakota Formation of southeastern Nebraska contains the first dinosaur tracks; Diagenesis; Isotopes; Dinosaur tracks; Carbonate cements 1. Introduction The preservation of fossils

González, Luis A.

260

Sedimentary facies and stratigraphic architecture in coarse-grained deltas: Anatomy of the Cenozoic Camaná Formation, southern Peru (16°25?S to 17°15?S)  

NASA Astrophysics Data System (ADS)

In the external forearc of southern Peru (Arequipa region), the sedimentary facies and the stratigraphic architecture of the Cenozoic Camaná Formation are presented in the context of tectono-eustatic controls. The Camaná Formation is defined as ?500 m thick coarse-grained deltaic complex that accumulated in a fault-bounded elongated depression extending from the Coastal Cordillera in the east to the offshore Mollendo Basin in the west and likely up to the Peruvian Trench. Based on the analysis of facies associations, we propose a refined stratigraphic scheme of the Camaná Basin fill. The Camaná Formation was formerly divided into the Camaná “A” and Camaná “B” units (CamA and CamB, respectively). We reinterpret the stratigraphic position and the timing of the CamA to CamB boundary, and define three sub-units for CamA, i.e. sub-units A1, A2, and A3. Each depositional unit shows individual stacking patterns, which are linked with particular shoreline trajectories through time. Strata of A1 form the basal succession of the Camaná Formation and consist of distributary channels and mouth bars, unconformably overlain by beds of A2. A2 consists of delta front deposits arranged in voluminous clinothems that reflect a progradational downstepping complex. A3 consists of delta front sandstones to prodelta siltstones arranged in retrogradational onlapping geometry. A pebbly intercalation in proximal onlapping A3 deposits is interpreted to reflect pulses of uplift in the hinterland. The overlying CamB unit is characterized by a thick alternation of fluvio-deltaic conglomerates and sand bars. The ages of the individual units of the Camaná Formation are not yet well defined. Based on the available information and stratigraphic correlations we tentatively assign A1 to the Late Oligocene, A2 to the Early Miocene, A3 to the late Early Miocene to early Middle Miocene, and CamB to the Late Miocene to? early Pliocene. The sub-units A1 and A2 represent a regressive systems tract, where the shoreline was forced to migrate seaward. This scenario differs from the Early Miocene eustatic sea-level rise suggesting that significant tectonic uplift along the Coastal Cordillera controlled the high sediment influx during A2 deposition. The sub-unit A3 represents a transgressive systems tract, triggering landward migration of the shoreline. This scenario is well in line with the global sea-level chart suggesting that A3 has been deposited during a phase of eustatic sea-level rise with minor tectonic activity. The fluvial deposits of CamB reflect an increased sediment flux due to uplift of the hinterland. The observed stratigraphic patterns support predominant tectonic control on sedimentation in the Camaná Basin and the established stratigraphic framework provides an essential baseline for future correlations of the Cenozoic sedimentation in the forearc area of the Central Andes.

Alván, Aldo; von Eynatten, Hilmar

2014-10-01

261

Hydrodynamic effect on oil accumulation in a stratigraphic trap, Kitty Field, Powder River Basin, Wyoming  

E-print Network

HYDRODYNAMIC EFFECT ON OIL ACCUMULATION IN A STRATIGRAPHIC TRAP, KITTY FIELD, POWDER RIVER BASIN, WYOMING A Thesis by GREGORY MARTIN LARBERG "I Submitted to the Graduate College of Texas A8M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE August 1976 Major Subject: Geology HYDRODYNAMIC EFFECT ON OIL ACCUMULATION IN A STRATIGRAPHIC TRAP, KITTY FIELD, POWDER RIVER BASIN, WYOMING A Thesis by GREGORY MARTIN LARBERG Approved as to style...

Larberg, Gregory Martin

1976-01-01

262

Building a Local Stratigraphic Column: A research-based assignment for an introductory course  

NSDL National Science Digital Library

Students build a stratigraphic column for a pre-selected area through the compilation of a series of individual research projects. Students are required to conduct introductory field research as well as a literature search to become "experts" on a selected stratigraphic unit. In addition to a final report, students will present their information at an outcrop on an end-of-semester field trip.

Jennifer Hargrave

263

Stratigraphic evidence for an early Holocene earthquake in Aceh, Indonesia  

NASA Astrophysics Data System (ADS)

The Holocene stratigraphy of the coastal plain of the Aceh Province of Sumatra contains 6 m of sediment with three regionally consistent buried soils above pre-Quaternary bedrock or pre-Holocene unconsolidated sediment. Litho-, bio-, and chronostratigraphic analyses of the lower buried soil reveals a rapid change in relative sea-level caused by coseismic subsidence during an early Holocene megathrust earthquake. Evidence for paleoseismic subsidence is preserved as a buried mangrove soil, dominated by a pollen assemblage of Rhizophora and/or Bruguiera/Ceriops taxa. The soil is abruptly overlain by a thin tsunami sand. The sand contains mixed pollen and abraded foraminiferal assemblages of both offshore and onshore environments. The tsunami sand grades upward into mud that contains both well-preserved foraminifera of intertidal origin and individuals of the gastropod Cerithidea cingulata. Radiocarbon ages from the pre- and post-seismic sedimentary sequences constrain the paleoearthquake to 6500-7000 cal. yrs. BP. We use micro-and macrofossil data to determine the local paleoenvironment before and after the earthquake. We estimate coseismic subsidence to be 0.45 ± 0.30 m, which is comparable to the 0.6 m of subsidence observed during the 2004 Aceh-Andaman earthquake on Aceh's west coast.

Grand Pre, Candace A.; Horton, Benjamin P.; Kelsey, Harvey M.; Rubin, Charles M.; Hawkes, Andrea D.; Daryono, Mudrik R.; Rosenberg, Gary; Culver, Stephen J.

2012-10-01

264

The effectiveness of 3-D marine systems as an exploration tool in the offshore Niger Delta  

SciTech Connect

From inception in 1984, three-dimensional (3-D) marine surveys have been used widely for field development where commercial hydrocarbons were known to exist in Nigeria. The high-trace density and full 3-D migration provide a data set that allows detailed interpretation of complex geologic structures and, in many cases, provides good stratigraphic information as well. The result has been better placement of development wells, making field development more efficient and cost effective. Previous application of the 3-d method (i.e., reconaissance 3-D) as an exploration tool in 1987 has demonstrated its effectiveness for predrilling detailing of prospects in offshore Niger Delta in a situation where a large volume of seismic data were acquired at relatively reduced unit costs. The technique involves acquiring data along a line every 200 m spacing, while interpretation in 3-D data processing is applied for subsequent 3-D migration. Based on pattern recognition of events on the input traces, the links are established to allow traces to be formed between input locations by comparing several attributes of events on neighboring traces. A case history example from the offshore Niger delta shows that the collection costs for the reconnaissance 3-D method are comparable to two-dimensional detailing based on similar line kilometer and time duration for the survey. A trade-off between cost and technical specifications can be programmed by focusing on the geologic objective. The technique brings the advantage of 3-D methods, but not their costs, to the exploration phase of the search for petroleum, and it is highly recommended for exploration in frontier areas, particularly the deep offshore of the Niger Delta.

Idowu, A.O. (Nigerian National Petroleum Corp., Lagos (Nigeria))

1993-09-01

265

Implications of Stratigraphic and Structural Data from the Bitter Spring Region, Southern Nevada  

NASA Astrophysics Data System (ADS)

Deposition of the Tertiary Horse Spring Formation (HSF) in southern Nevada has been used to infer varying styles of extensional and strike-slip basin formation. Beard (1996) proposes an initial large contiguous basin of Rainbow Gardens age (ca. 26-18 Ma) that is subsequently broken up into sub-basins during Thumb time (16-14 Ma). A key locality to test this hypothesis is near the southern end of East and West Longwell Ridges, on the Bitter Spring USGS 1:24000 quadrangle (BSQ). However, the stratigraphic framework in this area is poorly defined. The BSQ is located west of the Overton arm of Lake Mead near the junction of the Las Vegas Valley Shear Zone and the Lake Mead Fault System. By mapping a portion of the quadrangle at 1:5000 scale, measuring detailed sections, and collecting ash samples from key localities, we investigated the structural and sedimentary framework of the area and have begun to clarify the stratigraphic relationships between members of the HSF. Faults fall into three categories: one set strikes north and dips moderately to the west; another strikes east-northeast and dips shallowly to the northwest; and the last strikes north and dips to the east. Many of these faults show an oblique sense of movement and may be related to movement on the White Basin (WBF) and Rodgers Spring Faults (Bohannon, 1983). A distinctive resistant limestone caps gypsiferous and clastic units on both sides of the north-south trending WBF. To the west of the WBF, this limestone is mapped as the Bitter Ridge Limestone Member of the HSF, whereas to the east it is mapped as the Thumb Member by Beard (unpub) and as the Rainbow Gardens Member by Bohannon (1983). We suspect that these limestones may be correlative; geochemical and petrographic fingerprinting of numerous ashes from our sections should allow correlation of these units across the WBF. In addition, sections from the east side of the WBF spaced over 1.5 km show conglomerate at the base, overlain by a sequence of red sandstone, gypsum, and carbonates (mainly oncolitic and peloidal limestone). These units show rapid lateral facies changes and thickness variation suggesting comparable changes in accommodation-space creation, possibly related to extensionally-induced subsidence. Paleocurrent data from the central portion of the mapping area indicate that flow was east- to southeast-directed, indicating that West Longwell Ridge may have been a topographic high during Thumb time. This interpretation is further supported by stratigraphic relationships near the basin margin, where conglomerate was deposited in buttress contact against Paleozoic limestones at the southern end of the ridge. Future work in this area includes continued mapping, Ar-Ar dating of ash mineral phases, and provenance analysis of sedimentary units.

Donatelle, A.; Goeden, J.; Hannon, M.; Hickson, T.; Holter, S.; Johnson, T.; Lamb, M.; Lindberg, J.

2004-05-01

266

Proceedings of the 25th annual offshore technology conference. Volume 3 - Construction and installation/field drilling and development systems  

SciTech Connect

This conference represents one of four volumes on offshore operation of oil, gas, and other mineral resource projects. This particular volume deals with the installation and design of offshore production platforms, marine risers, underwater pipelines, and oil/gas wellheads. It discusses the operations of the various systems, gives comparative evaluations of systems, provides the results of various materials testing programs, provides various engineered safety systems, and designs for various forms of anchoring systems for floating platforms.

Not Available

1993-01-01

267

Sanaga Sud field - Offshore Cameroon, west Africa  

SciTech Connect

The Sanaga Sud field, offshore Cameroon, is located just northwest of the coastal town of Kribi in the northern part of the Douala basin. The discovery well, Sanaga Sud A-1, was drilled in 1979 to test an apparent horst block that contained a prominent horizontal seismic amplitude. The Douala basin is one of a series of passive margin basins located along the coastline of central and southern Africa, and formed during the rifting of Africa and South America during the Early Cretaceous. Drilling results showed that the amplitude was a gas/water contact. Two appraisal wells, SSA-2 and SSA-3, were drilled in 1981. All three wells tested gas and condensate. Total recoverable hydrocarbons for the field are estimated to be approximately 1 tcf of gas. The trap in this field is composed of tilted and rotated fault blocks composed of interbedded Aptian to Albian sandstones, siltstones, and shales. The fault blocks were truncated by erosion (breakup unconformity) and later buried by a considerable thickness of onlapping Upper Cretaceous and Tertiary shale. The late Albian erosional unconformity forms the top of the trap over most of the field. Geochemical studies indicate a Lower Cretaceous source for the hydrocarbons. The gross pay thickness averages 250 m with an average porosity of 23% and an average permeability of 142 md. Reservoir lithologies range from well-sorted, massive sandstones to poorly sorted fine sandstones and siltstones containing shaly laminations that are carbonaceous and micaceous. The field is located predominantly in Block PH-38, but part of the field is in the Londji concession. Mobil Producing Cameroon, Inc., is the operator of PH-38 and Total Exploration and Production Cameroon is the operator of the Londji concession.

Pauken, R.J. (Mobil New Exploration Ventures Co., Dallas, TX (USA))

1990-09-01

268

Polyamine sensitization in offshore workers handling drilling muds.  

PubMed

Oil-based mud, a complex mixture containing amines in emulsifiers, is used in offshore drilling operations. It is a skin irritant that occasionally gives rise to allergic contact sensitivity. In patch testing patients with allergy to drilling mud, we have identified polyamine (diethylenetriamine and triethylenetetramine) sensitivity in 5 patients. All 5 patients were also allergic to emulsifiers. These emulsifiers are cross-linked fatty acid amido-amines, in which unreacted amine groups are thought to cross-sensitize with these constituent polyamines. Cross-reactivity between ethylenediamine, diethylenetetramine and triethylenetetramine was found in 9 subjects. PMID:2533536

Ormerod, A D; Wakeel, R A; Mann, T A; Main, R A; Aldridge, R D

1989-11-01

269

The effects of second-order hydrodynamics on a semisubmersible floating offshore wind turbine  

NASA Astrophysics Data System (ADS)

The objective of this paper is to assess the second-order hydrodynamic effects on a semisubmersible floating offshore wind turbine. Second-order hydrodynamics induce loads and motions at the sum- and difference-frequencies of the incident waves. These effects have often been ignored in offshore wind analysis, under the assumption that they are significantly smaller than first-order effects. The sum- and difference-frequency loads can, however, excite eigenfrequencies of a floating system, leading to large oscillations that strain the mooring system or vibrations that cause fatigue damage to the structure. Observations of supposed second-order responses in wave-tank tests performed by the DeepCwind consortium at the Maritime Research Institute Netherlands (MARIN) offshore basin suggest that these effects might be more important than originally expected. These observations inspired interest in investigating how second-order excitation affects floating offshore wind turbines and whether second-order hydrodynamics should be included in offshore wind simulation tools like FAST. In this work, the effects of second-order hydrodynamics on a floating semisubmersible offshore wind turbine are investigated. Because FAST is currently unable to account for second-order effects, a method to assess these effects was applied in which linearized properties of the floating wind system derived from FAST (including the 6x6 mass and stiffness matrices) are used by WAMIT to solve the first- and second-order hydrodynamics problems in the frequency domain. The method was applied to the Offshore Code Comparison Collaboration Continuation OC4-DeepCwind semisubmersible platform, supporting the National Renewable Energy Laboratory's 5-MW baseline wind turbine. In this paper, the loads and response of the system caused by the second-order hydrodynamics are analysed and compared to the first-order hydrodynamic loads and induced motions in the frequency domain. Further, the second-order loads and induced response data are compared to the loads and motions induced by aerodynamic loading as solved by FAST.

Bayati, I.; Jonkman, J.; Robertson, A.; Platt, A.

2014-06-01

270

The Seabed Stability Zonation in Chinese Offshore  

NASA Astrophysics Data System (ADS)

There are abundant natural resources and energy in Chinese offshore continental shelf, and which should be the most development potential region now and in the future. But the seabed of Chinese offshore is often under the instable status caused by many factors which deeply affects the safety of marine development. Marine geohazards is an active one among the influence factors. The marine geohazards means the geological factors developed in the seabed surface and the strata below the seabed, such as fault, shallow gas, landslide, coastal erosion, buried river channel, sand wave and sand ridge, easily liquefied sand layer etc., which will cause damage to the human life and property. In this paper, the seabed stability were analyzed and divided it into five grades based on the marine geohazards evaluation result which made by fuzzy mathematic model. Firstly, by collecting the analyzing the marine geohazards which distributed on the seabed or under the seabed, the marine geohazards maps in Chinese offshore were made and the classification system of marine geohazards was established. Then, the evaluation index system of seabed stability was set which included the seismic peak acceleration, geomorphology, direct geohazards and restricted geohazards. And the weighted value of each indicator was calculated by using analytic hierarchy process. And, a group of appropriate number with normal distribution was selected to replace the membership grade function. Based on above, a fuzzy evaluation model for seabed stability is established. Using the maps of marine geohazards, geomorphology maps and seismic peak acceleration maps as data source, using the fuzzy matrix as calculated method, based on the principles of maximum membership grade of fuzzy mathematics, we get the evaluation result of Chinese offshore with 6' by 6' grid unit. The maximum membership grade should be taken as the stability level in each unit. Above all, the seabed stability of Chinese offshore is divided into five grades according to the maximum membership grade. In this paper, we defined 5 classes which respectively were basically stable, relatively stable, medium, relatively unstable and unstable. By using statistical analysis method, a stability zonation map of the Chinese offshore has been drawn based on the evaluation result of each unit. From the stability map, Chinese offshore seabed stability was divided into sixty sub-regions with 5 classes. And the unstable sub-regions were mainly located in the North-East of Liaodong Bay, north of Laizhou Bay, the shoal in north Jiangsu, north Taiwan offshore and around Nan'ao Islands of Guangdong. Most Chinese offshore seabed stability has been in the relatively stable status.

Du, J.

2013-12-01

271

The use of CPT and other Direct Push methods for (hydro-)stratigraphic aquifer characterization - a field study  

NASA Astrophysics Data System (ADS)

Environmental site investigations aim at delineating surface near (hydro-) stratigraphic units and their characterization. The knowledge about the spatial distribution of soil specific properties and hydraulic conductivity (K) is the prerequisite for understanding flow and fluid transport processes. This is especially true for remediation sites where complex structured sedimentary deposits can constrain remedial actions. Often, traditional site investigation techniques cannot cope with the task of high resolution aquifer characterization due to lack of resolution or high personnel expenditures. Direct Push (DP) sensor probes and tools are promising methods and are therefore frequently applied to generate high resolution vertical profiles of various soil specific properties of un- or weakly consolidated sedimentary soils for a reliable description of subsurface structures. Various sensor probes and other DP tools for the in situ (hydro-) stratigraphic subsurface characterization based on electrical, hydraulic, and textural soil properties have been engineered. These tools differ in working principle, application range, and resolution. Given the variety of tools, selected DP tools were tested for reproducibility as well as their ability to reflect soil variability and to predict K at a strongly heterogeneous aquifer with complex sedimentary architecture. Therefore, tools were tested at four probing clusters along a 58m long profile and compared to results of extensive grain size analysis and DP multilevel slug tests. Despite resolution differences, all of the applied methods captured the main aquifer structure whereat DP logging results are in good accordance to results of the grain size analysis. Correlation of the DP based K estimates and proxies with DP slug tests (DPST) show that it is possible to describe the aquifer hydraulic structure on less than a meter scale by combining DPST data and continuous DP measurements. Even though correlations are site specific and appropriate DP tools must be chosen, DP is reliable and efficient alternative for characterizing even strongly heterogeneous sites with complex structured sedimentary aquifers.

Vienken, T.; Leven, C.; Dietrich, P.

2010-12-01

272

Offshore oil gas trends in ROVs tooling  

SciTech Connect

The ROVs that operate in today's offshore environment bear little or no resemblance to those which first began supporting the oil and gas work requirements less than 15 years ago. In that short span of time, an explosion of subsea technology has occurred, rendering older equipment obsolete and expanding subsea remote intervention capabilities beyond the horizon of intervention tasks originally envisioned. Today's offshore work ROVs employ the latest in robotics, fiver optics, acoustics, video, and computer technologies, and routinely achieve better than 90 percent operational availability. Leading offshore ROV operations companies have demonstrated less than 1 percent down-time over thousands of hours of operation. As the offshore oil and gas market evolves, the ever-expanding capabilities of the work ROV plays a major role in shaping the operational concepts employed in subsea oil and gas field exploration, development, and production. This paper explores the capabilities of available ROV systems in use offshore today, the economic trends driving ROV technology development, and the new trends in the employment of ROVs and their associated sensors and tooling systems.

Jacobson, J.R. (Perry Tritech Inc., Jupiter, FL (United States))

1994-04-01

273

The International Subcommission on Stratigraphic Classification of the International Commission on Stratigraphy: The Knowledge  

NASA Astrophysics Data System (ADS)

The International Subcommission on Stratigraphic Classification (ISSC) was born in 1955 as an effort to promote awareness of stratigraphic principles and encourage worldwide standardization of stratigraphic approaches and terminology. The first major achievement of ISSC was the 1976 publication of the International Stratigraphic Guide. It was revised in 1994, with an abridged version appearing in 1999. These documents achieved their goals magnificently: cited innumerable times and forming the core of many national stratigraphic codes. As the discipline has evolved, particularly from technological advances and ocean drilling, new tools and methodologies have been developed and these have led to ever finer resolution of geological time and ever more exact correlation of stratigraphic units and events, thereby enhancing the understanding of the genesis of the geological record. Under the leadership of M. B. Cita, ISSC embarked in 2002 on a renewed initiative to disseminate to the global geological community these newer developments, and ultimately incorporate them into a third edition of the Guide. To this aim, traditional and new branches of stratigraphy are being treated: chemostratigraphy, cyclostratigraphy, magnetostratigraphy, lithostratigraphy, sequence stratigraphy, biostratigraphy, and chronostratigraphy. An open-access review paper is dedicated to each and published in Newsletters on Stratigraphy. The next edition of the Guide will be inclusive of all branches of stratigraphy and also embrace igneous and metamorphic rocks. It is envisaged that a textbook on stratigraphy based on these papers and the revised Guide could prove a timely contribution, especially to younger generations of practitioners, and aid global communication and understanding of stratigraphic principles and methods.

Pratt, Brian

2014-05-01

274

Federal Offshore Statistics, 1993. Leasing, exploration, production, and revenue as of December 31, 1993  

SciTech Connect

This document contains statistical data on the following: federal offshore lands; offshore leasing activity and status; offshore development activity; offshore production of crude oil and natural gas; federal offshore oil and natural gas sales volume and royalties; revenue from federal offshore leases; disbursement of federal offshore revenue; reserves and resource estimates of offshore oil and natural gas; oil pollution in US and international waters; and international activities and marine minerals. A glossary is included.

Francois, D.K.

1994-12-31

275

Effect of Second-Order Hydrodynamics on Floating Offshore Wind Turbines: Preprint  

SciTech Connect

Offshore winds are generally stronger and more consistent than winds on land, making the offshore environment attractive for wind energy development. A large part of the offshore wind resource is however located in deep water, where floating turbines are the only economical way of harvesting the energy. The design of offshore floating wind turbines relies on the use of modeling tools that can simulate the entire coupled system behavior. At present, most of these tools include only first-order hydrodynamic theory. However, observations of supposed second-order hydrodynamic responses in wave-tank tests performed by the DeepCwind consortium suggest that second-order effects might be critical. In this paper, the methodology used by the oil and gas industry has been modified to apply to the analysis of floating wind turbines, and is used to assess the effect of second-order hydrodynamics on floating offshore wind turbines. The method relies on combined use of the frequency-domain tool WAMIT and the time-domain tool FAST. The proposed assessment method has been applied to two different floating wind concepts, a spar and a tension-leg-platform (TLP), both supporting the NREL 5-MW baseline wind turbine. Results showing the hydrodynamic forces and motion response for these systems are presented and analysed, and compared to aerodynamic effects.

Roald, L.; Jonkman, J.; Robertson, A,; Chokani, N.

2013-07-01

276

Petroleum geology of the Norphlet formation (Upper Jurassic), S. W. and offshore Alabama  

Microsoft Academic Search

Recent successful gas test in the Norphlet formation (up to 26 million CF\\/day) at depths exceeding 20,500 ft in the Mobile Bay area demonstrate a high potential for hydrocarbon production in the Alabama offshore area. In addition, wells drilled in the upper Mobile Bay area could encounter gas condensate in the Norphlet formation; gas condensate is being produced from wells

E. A. Mancini; R. M. Mink; B. L. Bearden

1984-01-01

277

Operational mode monitoring of gas turbines in an offshore gas gathering application  

Microsoft Academic Search

A computer-assisted monitoring system has been implemented on GT-61 Gas Turbines employed in offshore gas gathering. Operating load data are continuously recorded at the site and evaluated at the turbine manufacturer's plant on a mainframe computer, where existing analysis and testing techniques are utilized to predict the service fatigue lives of the power turbine structural components. The data acquisition hardware,

D. F. Toler; R. N. Yorio

1984-01-01

278

LEEDCo awarded $4 million to launch offshore wind development on Lake Erie  

E-print Network

to build wind turbines in Lake Erie. "This is a great day for Northeast Ohio," said LEEDCo CEO Lorry Wagner in renewable energy manufacturing and use," he said. LEEDCo plans to install nine wind turbines on "ice breaker is considered an optimal location to test offshore wind energy. Brown noted that the world's first electric

Rollins, Andrew M.

279

SUBSPACE-BASED DETECTION OF FATIGUE DAMAGE ON JACKET SUPPORT STRUCTURES OF OFFSHORE WIND TURBINES  

E-print Network

SUBSPACE-BASED DETECTION OF FATIGUE DAMAGE ON JACKET SUPPORT STRUCTURES OF OFFSHORE WIND TURBINES turbine structures. Aim of the study was therefore to analyze the usability and effi- ciency structures of wind energy turbines. Based on results of an experimental fatigue test on a steel frame

Paris-Sud XI, Université de

280

Genetic differentiation between inshore and offshore Atlantic cod (Gadus morhua)  

E-print Network

Genetic differentiation between inshore and offshore Atlantic cod (Gadus morhua) off Newfoundland, and Sally V. Goddard Abstract: The genetic difference between inshore overwintering Atlantic cod (Gadus morhua) from Trinity Bay, Newfoundland, and offshore overwintering cod from the Grand Bank region

Ruzzante, Daniel E.

281

Strengthening America's Energy Security with Offshore Wind (Fact Sheet)  

SciTech Connect

This fact sheet describes the current state of the offshore wind industry in the United States and the offshore wind research and development activities conducted the U.S. Department of Energy Wind and Water Power Program.

Not Available

2012-02-01

282

Solar power satellite offshore rectenna study  

NASA Technical Reports Server (NTRS)

Offshore rectennas are feasible and cost competitive with land rectennas but the type of rectenna suitable for offshore use is quite different from that specified in the present reference system. A nonground plane design minimizes the weight and greatly reduces the number of costly support towers. This perferred design is an antenna array consisting of individually encapsulated dipoles with reflectors or tagis supported on feed wires. Such a 5 GW rectenna could be built at a 50 m water depth site to withstand hurricane, winter storm, and icing conditions for a one time cost of $5.7 billion. Subsequent units would be about 1.3 less expensive. More benign and more shallow water sites would result in substantially lower costs. The major advantage of an offshore rectenna is the removal of microwave radiation from populated areas.

1980-01-01

283

Investigation on installation of offshore wind turbines  

NASA Astrophysics Data System (ADS)

Wind power has made rapid progress and should gain significance as an energy resource, given growing interest in renewable energy and clean energy. Offshore wind energy resources have attracted significant attention, as, compared with land-based wind energy resources, offshore wind energy resources are more promising candidates for development. Sea winds are generally stronger and more reliable and with improvements in technology, the sea has become a hot spot for new designs and installation methods for wind turbines. In the present paper, based on experience building offshore wind farms, recommended foundation styles have been examined. Furthermore, wave effects have been investigated. The split installation and overall installation have been illustrated. Methods appropriate when installing a small number of turbines as well as those useful when installing large numbers of turbines were analyzed. This investigation of installation methods for wind turbines should provide practical technical guidance for their installation.

Wang, Wei; Bai, Yong

2010-06-01

284

Beaufortian stratigraphic plays in the National Petroleum Reserve - Alaska (NPRA)  

USGS Publications Warehouse

The Beaufortian megasequence in the National Petroleum Reserve in Alaska (NPRA) includes Jurassic through lower Cretaceous (Neocomian) strata of the Kingak Shale and the overlying pebble shale unit. These strata are part of a composite total petroleum system involving hydrocarbons expelled from source rocks in three stratigraphic intervals, the Lower Jurassic part of the Kingak Shale, the Triassic Shublik Formation, and the Lower Cretaceous gamma-ray zone (GRZ) and associated strata. The potential for undiscovered oil and gas resources in the Beaufortian megasequence in NPRA was assessed by defining eight plays (assessment units), two in lower Cretaceous (Neocomian) topset seismic facies, four in Upper Jurassic topset seismic facies, one in Lower Jurassic topset seismic facies, and one in Jurassic through lower Cretaceous (Neocomian) clinoform seismic facies. The Beaufortian Cretaceous Topset North Play is estimated to contain between 0 (95-percent probability) and 239 (5-percent probability) million barrels of technically recoverable oil, with a mean (expected value) of 103 million barrels. The Beaufortian Cretaceous Topset North Play is estimated to contain between 0 (95-percent probability) and 1,162 (5-percent probability) billion cubic feet of technically recoverable, nonassociated natural gas, with a mean (expected value) of 405 billion cubic feet. The Beaufortian Cretaceous Topset South Play is estimated to contain between 635 (95-percent probability) and 4,004 (5-percent probability) billion cubic feet of technically recoverable, nonassociated natural gas, with a mean (expected value) of 2,130 billion cubic feet. No technically recoverable oil is assessed in the Beaufortian Cretaceous Topset South Play, as it lies at depths that are entirely in the gas window. The Beaufortian Upper Jurassic Topset Northeast Play is estimated to contain between 2,744 (95-percent probability) and 8,086 (5-percent probability) million barrels of technically recoverable oil, with a mean (expected value) of 5,176 million barrels. No technically recoverable gas is assessed in the Beaufortian Upper Jurassic Topset Northeast Play. The Beaufortian Upper Jurassic Topset Northwest Play is estimated to contain between 733 (95-percent probability) and 3,312 (5-percent probability) million barrels of technically recoverable oil, with a mean (expected value) of 1,859 million barrels. No technically recoverable gas is assessed in the Beaufortian Upper Jurassic Topset Northwest Play. The Beaufortian Upper Jurassic Topset Southeast Play is estimated to contain between 2,053 (95-percent probability) and 9,030 (5-percent probability) billion cubic feet of technically recoverable, nonassociated natural gas, with a mean (expected value) of 5,137 billion cubic feet. No technically recoverable oil is assessed in the Beaufortian Upper Jurassic Topset Southeast Play, as it lies at depths that are entirely in the gas window. The Beaufortian Upper Jurassic Topset Southwest Play is estimated to contain between 2,008 (95-percent probability) and 9,265 (5-percent probability) billion cubic feet of technically recoverable, nonassociated natural gas, with a mean (expected value) of 5,220 billion cubic feet. No technically recoverable oil is assessed in the Beaufortian Upper Jurassic Topset Southwest Play, as it lies at depths that are entirely in the gas window. The Beaufortian Lower Jurassic Topset Play is estimated to contain between 0 (95-percent probability) and 210 (5-percent probability) million barrels of technically recoverable oil, with a mean (expected value) of 83 million barrels. The Beaufortian Lower Jurassic Topset Play is estimated to contain between 0 (95-percent probability) and 1,915 (5-percent probability) billion cubic feet of technically recoverable, nonassociated natural gas, with a mean (expected value) of 793 billion cubic feet. The Beaufortian Clinoform Play is estimated to contain between 0 (95-percent probability)

Houseknecht, David W.

2003-01-01

285

Preliminary stratigraphic and petrologic characterization of core samples from USW-G1, Yucca Mountain, Nevada  

SciTech Connect

Tuffs of the Nevada Test Site are currently under investigation to determine their potential for long-term storage of radioactive waste. As part of this program, hole USW-G1 was drilled to a depth of 6000 ft below the surface, in the central part of the Yucca Mountain area, Nevada Test Site, Nevada. Petrographic study of the USW-G1 core is presented in this report and shows the tuffs (which generally were variably welded ash flows) are partly recrystallized to a variety of secondary minerals. The important alteration products are zeolites (heulandite, clinoptilolite, mordenite and analcime), smectite clays with minor interstratified illite, albite, micas, potassium feldspar, and various forms of silica. Iijima`s zeolite zones I through IV of burial metamorphism can be recognized in the core. Zeolites are first observed at about the 1300-ft depth, and the high-temperature boundary of zeolite stability in this core occurs at about 4350 ft. Analcime persists, either metastably or as a retrograde mineral, deeper in the core. The oxidation state of Fe-Ti oxide minerals, through most of the core, increases as the degree of welding decreases, but towards the bottom of the hole, reducing conditions generally prevail. Four stratigraphic units transected by the core may be potentially favorable sites for a waste repository. These four units, in order of increasing depth in the core, are (1) the lower cooling unit of the Topopah Spring Member, (2) cooling unit II of the Bullfrog Member, (3) the upper part of the Tram tuff, and (4) the Lithic-rich tuff.

Waters, A.C.; Carroll, P.R. (eds.)

1981-11-01

286

3D stratigraphic forward modelling of Shu'aiba Platform stratigraphy in the Bu Hasa Field, Abu Dhabi, United Arab Emirates.  

NASA Astrophysics Data System (ADS)

This paper presents the results of three dimensional sequence stratigraphic forward modelling of the Aptian age Shu'aiba Formation from Abu Dhabi, United Arab Emirates (UAE). The Shu'aiba Formation lies within the uppermost part of the Lower Cretaceous Thamama Group and forms one of the most prolific hydrocarbon reservoir intervals of the Middle East with production dating back to the 1960's. The Shu'aiba Formation developed as a series of laterally-extensive shallow-water carbonate platforms in an epeiric sea that extended over the northern margin of the African-Arabian Plate. This shallow sea was bounded by the Arabian Shield to the west and the passive margin with the Neo-Tethys Ocean towards the north and east (Droste, 2010). The exposed Arabian Shield acted as a source of siliciclastic sediments to westernmost regions, however, more offshore areas were dominated by shallow-water carbonate deposition. Carbonate production was variously dominated by Lithocodium-Baccinella, orbitolinid foraminifera and rudist bivalves depending on local conditions. While there have been numerous studies of this important stratigraphic interval (for examples see van Buchem et al., 2010), there has been little attempt to simulate the sequence stratigraphic development of the formation. During the present study modelling was undertaken utilising the CARBONATE-3D stratigraphic forward modelling software (Warrlich et al., 2008; Warrlich et al., 2002)) thus allowing for the control of a diverse range of internal and external parameters on carbonate sequence development. This study focuses on platform development in the onshore Bu Hasa Field - the first giant oilfield to produce from the Shu'aiba Formation in Abu Dhabi. The carbonates of the Bu Hasa field were deposited on the southwest slope of the intra-shelf Bab Basin, siliciclastic content is minor. Initially these carbonates were algal dominated with rudist mounds becoming increasingly important over time (Alsharhan, 1987). Numerous simulations were undertaken, employing different sea level curves, platform geometries, etc. in order to accurately constrain and compare simulated facies geometries with those hypothesised from subsurface correlations. An initial low-angle ramp geometry was later overprinted by the development of localised relief through faulting and salt diapirism. Areas of bathymetric relief became sites of enhanced carbonate development with over-production resulting in aggradational geometries rapidly evolving to progradational systems. Several different regional, global and composite relative sea level curves were employed in the simulations in order to produce stratigraphic geometries comparable to those reported from previous studies. We conclude that none of the published sea level curves produce facies geometries directly analogous to those hypothesised from the sub-surface. We infer that this disparity primarily results from previous models lacking sufficient accommodation space and employing unrealistic carbonate production rates.

Hu, J.; Lokier, S. W.

2012-04-01

287

THE GULF OF MEXICO OFFSHORE AQUACULTURE CONSORTIUM1  

Microsoft Academic Search

Marine aquaculture may be classified into four categories according to the degree of protection afforded to the operation by the site characteristics: land-based operations; coastal, protected aquaculture; coastal, exposed aquaculture; and, offshore aquaculture. Offshore operations have all the logistical challenges of both remote coastal and exposed aquaculture but at an escalated scale. In 1999, the Gulf of Mexico Offshore Aquaculture

Christopher J. Bridger

288

CHAPTER 4 ENGINEERING REQUIREMENTS & LOGISTIC ALLEVIATION FOR OFFSHORE AQUACULTURE1  

Microsoft Academic Search

Offshore aquaculture—operating out of the sight of land—will have the logistic requirements associated with near shore operations, plus a new set of issues associated with the higher energy of the site and increased distance from shore. The Gulf of Mexico Offshore Aquaculture Consortium has been confronted by these challenges and has developed a suite of components to manage offshore aquaculture

Christopher J. Bridger; Clifford A. Goudey

289

Offshore Aquaculture: The Frontier of Redefining Oceanic Property  

Microsoft Academic Search

Over the past decade, offshore aquaculture has gained significant momentum as a global and, in particular, a U.S. seafood development strategy. Issues surrounding property rights, environmental impacts, and the social desirability of offshore aquaculture are inadequately addressed by policymakers and aquaculture specialists. This review essay describes offshore aquaculture's place in the development of industrial fish farming and the policy issues

Michael Skladany; Rebecca Clausen; Ben Belton

2007-01-01

290

77 FR 63849 - National Offshore Safety Advisory Committee  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF HOMELAND SECURITY Coast Guard...National Offshore Safety Advisory Committee...National Offshore Safety Advisory Committee...issues related to safety of operations...gas offshore industry. These meetings...Hobby Airport Hotel, 9100 Gulf Freeway...Department of Homeland Security'' and...

2012-10-17

291

78 FR 18614 - National Offshore Safety Advisory Committee  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF HOMELAND SECURITY Coast Guard...National Offshore Safety Advisory Committee...National Offshore Safety Advisory Committee...issues related to safety of operations...gas offshore industry. These meetings...Baronne Plaza Hotel, 201 Baronne...Department of Homeland Security'' and...

2013-03-27

292

Study on RMB offshore financial market of Hong Kong  

Microsoft Academic Search

It is essential to develop RMB offshore financial market in the process of promoting RMB internationalization. Hong Kong becomes the perfect place for constructing RMB offshore financial market due to its natural geography, developed busi- ness, strong infrastructure, a perfect system and other advan- tages. At present, the basic architecture of RMB offshore finan- cial market in Hong Kong has

Hongliang Wang

2011-01-01

293

ForPeerReview PUBLIC ACCEPTANCE OF OFFSHORE WIND POWER  

E-print Network

ForPeerReview PUBLIC ACCEPTANCE OF OFFSHORE WIND POWER PROJECTS IN THE UNITED STATES Journal: Wind, Andrew; Minerals Management Service Keywords: offshore wind power, public opinion, social acceptancePeerReview 1 PUBLIC ACCEPTANCE OF OFFSHORE WIND POWER PROJECTS IN THE UNITED STATES Jeremy Firestone*, Willett

Firestone, Jeremy

294

United States Offshore Wind Resource Assessment  

NASA Astrophysics Data System (ADS)

The utilization of the offshore wind resource will be necessary if the United States is to meet the goal of having 20% of its electricity generated by wind power because many of the electrical load centers in the country are located along the coastlines. The United States Department of Energy, through its National Renewable Energy Laboratory (NREL), has supported an ongoing project to assess the wind resource for the offshore regions of the contiguous United States including the Great Lakes. Final offshore maps with a horizontal resolution of 200 meters (m) have been completed for Texas, Louisiana, Georgia, northern New England, and the Great Lakes. The ocean wind resource maps extend from the coastline to 50 nautical miles (nm) offshore. The Great Lake maps show the resource for all of the individual lakes. These maps depict the wind resource at 50 m above the water as classes of wind power density. Class 1 represents the lowest available wind resource, while Class 7 is the highest resource. Areas with Class 5 and higher wind resource can be economical for offshore project development. As offshore wind turbine technology improves, areas with Class 4 and higher resource should become economically viable. The wind resource maps are generated using output from a modified numerical weather prediction model combined with a wind flow model. The preliminary modeling is performed by AWS Truewind under subcontract to NREL. The preliminary model estimates are sent to NREL to be validated. NREL validates the preliminary estimates by comparing 50 m model data to available measurements that are extrapolated to 50 m. The validation results are used to modify the preliminary map and produce the final resource map. The sources of offshore wind measurement data include buoys, automated stations, lighthouses, and satellite- derived ocean wind speed data. The wind electric potential is represented as Megawatts (MW) of potential installed capacity and is based on the square kilometers (sq. km) of Class 5 and higher wind resource found in a specific region. NREL uses a factor of 5 MW of installed capacity per sq. km of "windy water" for its raw electric potential calculations. NREL uses Geographic Information System data to break down the offshore wind potential by state, water depth, and distance from shore. The wind potential estimates are based on the updated maps, and on previous offshore resource information for regions where new maps are not available. The estimates are updated as new maps are completed. For example, the updated Texas offshore map shows almost 3000 sq. km of Class 5 resource within 10 nm of shore and nearly 2000 sq. km of Class 5 resource or 10,000 MW of potential installed capacity in water depths of less than 30 m. NREL plans to develop exclusion criteria to further refine the offshore wind potential

Schwartz, M.; Haymes, S.; Heimiller, D.

2008-12-01

295

Significance of the basin wide reverse polarity reflector in the Offshore Sydney Basin, East Australian Margin  

NASA Astrophysics Data System (ADS)

The Offshore Sydney Basin is located between latitudes 32°30'S and 34°30'S between the coastal cities of Newcastle in the north and Wollongong in the south, covering a total area of ~15,000 squire km. The structural framework of the offshore portion of the basin comprises five principal elements: the Offshore Syncline, an extension of the New England Fold Belt, an offshore extension of the Newcastle Syncline, the Offshore Uplift and the Outer Continental Shelf. The present easterly extent of the basin is the result of Cretaceous rifting and commencement of seafloor spreading in the adjacent Tasman Sea. The continental shelf is approximately 50 km wide offshore Sydney and is edged by relatively steep continental slope. This study has been carried out with 2D multichannel seismic data covering the northern half of the offshore basin. The Cenozoic sedimentary cover of the basin is characterized by two regional unconformities: one at the base of Cenozoic and another intra-Cenozoic. The unconformity at the base of Cenozoic is known as the Top Sydney Basin unconformity. In places the surface is displaced by faults and also characterized by possible mounds producing an overall highly irregular topography. Though most of the faults remained buried beneath the surface some continued up to seafloor. They seem to have NW-SE direction with significant lateral extension. The intra-Cenozoic unconformity forms a prominent reflector at about 80 to 200 msbs (TWT). It is characterized by an angular unconformity with the reflectors terminating onto it from beneath. It is also associated with prograding sequences beneath, terminating with toplap geometry, suggesting that it forms the boundary between a transgressive and regressive phase. This is interpreted as a prograding carbonate dominated shelf-edge. The most interesting aspect of this seismic reflector is that the major part of it presents reverse polarity with respect to the seafloor reflection. The amplitude of the reflector changes laterally and is characterized by patches of high amplitude (bright spots). Contour mapping shows that this reverse polarity reflector is continuous and regionally distributed. The depth of the reflector with respect to the sea surface is too shallow to be a BSR, typically caused at the interface between hydrate containing sediments above and free gas below. Reverse polarity is a common indicator of the accumulation of hydrocarbons. However, alternatively in such shallow depth it can also be caused by the presence of a soft sediment layer. Another important point to note is that no chimney or any other gas escape features have been observed in the vicinity originating from the reverse polarity reflector. However, in the adjacent continental slope, giant pockmarks have been observed on the bathymetry data. They most probably originated from gas sources in Permian coal measures. In order to understand what is causing this reverse polarity further quantitative analysis such as AVO and inversion has been done. AVO analysis and subsequent inversion of selected seismic lines show that some parts of the reversed polarity are characterized by bright spots, especially on the hanging wall side of the major faults, caused by the presence of gas. The stratigraphic position of the reflector suggests that the anomalous horizon could have been formed during the low-stand that followed the high-stand progradation event seen on dip sections. The gas accumulation could then be associated with "back reef" carbonates that during the low stand have been subjected to karstification causing the gas entrapment in vugular pore spaces.

Rahman Talukder, Asrarur; Nadri, Dariush; Rajput, Sanjeev; Clennell, Ben; Griffiths, Cedric; Breeze, David

2010-05-01

296

Gas Production From a Cold, Stratigraphically Bounded Hydrate Deposit at the Mount Elbert Site, North Slope, Alaska  

SciTech Connect

As part of an effort to identify suitable targets for a planned long-term field test, we investigate by means of numerical simulation the gas production potential from unit D, a stratigraphically bounded (Class 3) permafrost-associated hydrate occurrence penetrated in the ount Elbert well on North Slope, Alaska. This shallow, low-pressure deposit has high porosities, high intrinsic permeabilities and high hydrate saturations. It has a low temperature because of its proximity to the overlying permafrost. The simulation results indicate that vertical ells operating at a constant bottomhole pressure would produce at very low rates for a very long period. Horizontal wells increase gas production by almost two orders of magnitude, but production remains low. Sensitivity analysis indicates that the initial deposit temperature is y the far the most important factor determining production performance (and the most effective criterion for target selection) because it controls the sensible heat available to fuel dissociation.

Moridis, G.J.; Silpngarmlert, S.; Reagan, M. T.; Collett, T.S.; Zhang, K.

2009-09-01

297

Stratigraphic relations and hydrologic properties of the Paintbrush Tuff (PTn) hydrologic unit, Yucca Mountain, Nevada  

SciTech Connect

Yucca Mountain is being investigated as a potential site for a high- level nuclear waste repository. The intent of this study was to clarify stratigraphic relations within the Paintbrush Tuff (PTn) unit at Yucca Mountain in order to better understand vertical and lateral variations in hydrologic properties as they relate to the lithologic character of these rocks. This report defines informal stratigraphic units within the PTn interval, demonstrates their lateral continuity in the Yucca Mountain region, describes later and vertical variations within them, and characterizes their hydrologic properties and importance to numerical flow and transport models. We present tables summarizing the depth to stratigraphic contacts in cored borehole studies, and unit descriptions and correlations in 10 measured sections.

Moyer, T.C.; Geslin, J.K. [Science Applications International Corp., Golden, CO (United States); Flint, L.E. [U.S. Geological Survey, Yucca Mountain Project, Mercury, NV (United States)

1996-08-01

298

Hierarchical construction of stratigraphic elements in surface-based reservoir models  

NASA Astrophysics Data System (ADS)

We present a surface-based simulation algorithm connecting stratigraphic hierarchy with surface-based reservoir models through statistical metrics. Geostatistical simulation algorithms provide tools for modeling spatial complexity and the resulting uncertainties for energy resource assessments. As a new family within a wide array of stochastic geological models, surface-based models and rule-based algorithms effectively represent stratigraphic responses to geological events in both time and space by assigning depositional and erosional surfaces with predefined geometries and rules. Recent advances in surface-based modeling focus on simulating morphological evolution of deep-water depositional systems and constraining models to available well and seismic data. However, especially in deep-water plays, scarce well data can only bring information about local stratal features rather than relatively general information such as hierarchy or organization, when these features are below seismic resolution. Without such information, surface-based models lack geological realism and may not be reliable even when conditioned to data. Our proposed surface-based simulation algorithm links stratigraphic hierarchy with surface-based reservoir modeling through spatial statistical tools. Ripley's K-function is used to quantitatively describe the stratigraphic distribution patterns of channel deposits. We also use the compensation index metric for quantifying the strength of compensational stacking in stratigraphic elements. These two metrics help us to extract information about sedimentary hierarchy and element organization from a set of experimental strata, and bridge physical tank experiments with numerical models. We utilize these two geostatistical metrics in conjunction with a surface-based simulation algorithm to 1) integrate clustering and compensational stacking patterns of channel deposits into reservoir modeling 2) make numerical models represent a stratigraphic hierarchical framework comparable to physical tank experiments 3) explore a means of imparting stochastic structures to models and improving geological realism. These models can be used to better assess subsurface spatial uncertainty.

Wang, Y.; Xu, S.; Mukerji, T.

2013-12-01

299

Solar power satellite offshore rectenna study  

NASA Technical Reports Server (NTRS)

It was found that an offshore rectenna is feasible and cost competitive with land rectennas but that the type of rectenna which is suitable for offshore use is quite different from that specified in the present reference system. The result is a nonground plane design which minimizes the weight and greatly reduces the number of costly support towers. This preferred design is an antenna array consisting of individually encapsulated dipoles with reflectors supported on feed wires. Such a 5 GW rectenna could be built at a 50 m water depth site to withstand hurricane and icing conditions for a one time cost of 5.7 billion dollars. Subsequent units would be about 1/3 less expensive. The east coast site chosen for this study represents an extreme case of severe environmental conditions. More benign and more shallow water sites would result in lower costs. Secondary uses such as mariculture appear practical with only minor impact on the rectenna design. The potential advantages of an offshore rectenna, such as no land requirements, removal of microwave radiation from populated areas and minimal impact on the local geopolitics argue strongly that further investigation of the offshore rectenna should be vigorously pursued.

1980-01-01

300

Competitive Bidding for Offshore Petroleum Leases  

Microsoft Academic Search

This paper develops a formal model of competitive bidding to analyze some aspects of the federal offshore oil leasing system. The lease sales of interest are often characterized by small numbers of auction participants and by high levels of uncertainty regarding the true values of the leases offered. The model suggests that these circumstances may lead to the capture of

Douglas K. Reece

1978-01-01

301

CHOOSING OFFSHORE PIPELINE ROUTES: PROBLEMS AND SOLUTIONS  

EPA Science Inventory

The report discusses the environmental and fisheries problems associated with offshore pipelines. The report focuses on how these problems can be addressed during the pipeline planning and route selection process. Geologic hazards are highlighted as the major factors related to p...

302

MFR PAPER 1179 Offshore Headboat Fishing in  

E-print Network

MFR PAPER 1179 Offshore Headboat Fishing in North Carolina and South Carolina GENE R. HUNTSMAN ABSTRACT-Headboats operating on the outer Continental Shelf of North Carolina and South Carolina made Carolina and South Carolina1 . Despite the northerly latitude of this fishery, it produces large catches

303

Sea Stars Underwater Offshore Northern California  

USGS Multimedia Gallery

Three sea stars on a rock, surrounded by a sandy seafloor littered with broken shells. Each sea star is approx. 10 - 15 cm (4-6 inches) across. Image acquired 4.5 km (3 miles) offshore Pigeon Point, southern San Mateo County, California at a depth of 52 meters....

304

Fish Swimming Underwater Offshore Northern California  

USGS Multimedia Gallery

A kelp greenling fish swimming above a seafloor of mixed gravel, cobble and rock outcrop with scattered shell. Fish is approx. 20 cm (8 inches) long. Image acquired 1 km (0.62 miles) offshore Half Moon Bay, California at a depth of 14 meters (46 ft). Also in the image are encrusting sponge...

305

Offshore mussel aquaculture: new or just renewed?  

Microsoft Academic Search

The increase on the demand for marine products and the decrease of the wild marine population has led to the culturing of several marine species. Within the molluscs the mussel is the second largest product by volume of marine aquaculture. Mussels are an ideal species for culture in the open ocean, referred to as offshore aquaculture. Several different systems are

T. Lado-Insua; F. J. Ocampo; K. Moran

2009-01-01

306

Offshore Wind Power Farm Environmental Impact Assessment  

E-print Network

Horns Rev Offshore Wind Power Farm Environmental Impact Assessment on Water Quality #12;Prepared Design ApS 04.05.2000 #12;Bio/consult Side 3 Horns Rev. Environmental Impact Assessment. Water Quality ................................................................................................................................. 12 4.2. WATER QUALITY

307

Offshore Investments by Colleges Draw Scrutiny  

ERIC Educational Resources Information Center

Billions of dollars in untaxed, offshore investments by college endowments could be subject to taxation under a proposal being considered by the leaders of the U.S. Senate Finance Committee. The proposed change, which targets hedge funds, a popular investing strategy for many colleges, would affect the largest college endowments, including those…

Fain, Paul; Wolverton, Brad

2007-01-01

308

Gladden Pull-Apart Basin, offshore Belize  

Microsoft Academic Search

The junction of the American and Caribbean plates in Belize has created a complex structural setting for oil and gas exploration. Recent seismic offshore Belize has been used to identify three structural provinces, from west to east: a shallow thrust zone, a narrow upthrown wrench faulted zone and a deeper extensional basin, named the Gladden Pull-Apart Basin. Hydrocarbon leakage from

Morrice

1993-01-01

309

Accord near for offshore California oil shipments  

SciTech Connect

There are faint glimmers of hope again for offshore California operators. After more than a decade of often bitter strife over offshore oil and gas development and transportation issues, state officials and oil producers may be moving toward compromise solutions. One such solution may be forthcoming on offshore development. But the real change came with the turnabout of the California Coastal Commission (CCC), which last month approved a permit for interim tankering of crude from Point Arguello oil field in the Santa Barbara Channel to Los Angeles. The dispute over how to ship offshore California crude to market has dragged on since before Point Arguelo development plans were unveiled. The project's status has become a flashpoint in the U.S. debate over resource use and environmental concerns. The controversy flared anew in the wake of the 1989 Exxon Valdez tanker spill off Alaska, when CCC voided a Santa Barbara County permit for interim tankering, a move project operator Chevron Corp. linked to the Exxon Valdez accident. Faced with litigation, the state's economic devastation, and acrimonious debate over transporting California crude, Gov. Pete Wilson and other agencies approved the CCC permit. But there's a catch: A permanent pipeline must be built to handle full production within 3 years. The paper discusses permit concerns, the turnaround decision, the anger of environmental groups, and pipeline proposals.

Not Available

1993-02-15

310

Human Rights, Academic Freedom, and Offshore Academics  

ERIC Educational Resources Information Center

Despite the carnage wrought on higher education by the Great Recession, evidence persists that the sector is still host to a speculator psychology. One example is the unabated stampede to set up branches and programs overseas. Colleges have many reasons to go offshore: (1) to reduce costs; (2) to build their "brands" in "emerging markets"; and (3)…

Ross, Andrew

2011-01-01

311

Highwave off-shore energy hose  

Microsoft Academic Search

Many inshore wave energy collectors (WEC) concepts use wave energy to push water ashore to process it for energy conversion with turbines. An artificial reef design of floating HPDE pipe can be built in a harbor and installed offshore of the breaking waves in the near shore. The portable reef designed to mitigate shore erosion can serve as the shuttle

Gary Ross; A. Michael Weaver; Chris O'Connor

2011-01-01

312

Planning and evaluation parameters for offshore complexes  

NASA Technical Reports Server (NTRS)

Issues are presented for consideration in the planning and design of offshore artificial complexes. The construction of such complexes, their social, economic, and ecological impacts, and the legal-political-institutional environments within which their development could occur, are discussed. Planning, design, and construction of near-shore complexes located off the Mid-Atlantic coast of the United States is emphasized.

Sincoff, M. Z. (editor); Dajani, J. S. (editor)

1976-01-01

313

Rocky and Sandy Seafloor Offshore California  

USGS Multimedia Gallery

Image of ripples in sand, next to a rocky surface on the seafloor 2.5 km (1.5 miles) offshore San Mateo County, California at a depth of 24.6 meters (81 feet). The two red dots in the image (from lasers mounted on the camera and used as reference points) are 15 cm (6 inches) apa...

314

Cut drydocking costs for offshore rigs  

SciTech Connect

Heavy-lift transport vessels (HLVs) can provide an economic alternative to the conventional shipyard approach of drydocking mobile offshore rigs for regulatory body inspections and/or repairs. Contractors now can drydock rigs in areas of the world where conventional drydocks are unavailable. This article discusses pros and cons of conventional shipyard drydocking and the HLV approach.

Albaugh, E.K.

1985-07-01

315

Hydrocarbon potential of offshore South Florida basin  

Microsoft Academic Search

The results of an extensive, detailed geologic and geophysical evaluation of the offshore South Florida basin show this area to have considerable hydrocarbon exploration potential. Geophysical mapping on six key horizons identified numerous structural closures at Dollar Bay through Bone Island mapping levels. Geologic evaluation indicated at least four viable potential reservoir horizons, including the Sunniland formation - the main

B. M. Faulkner; A. V. Applegate

1986-01-01

316

Multiple Offshore Bars and Standing Waves  

Microsoft Academic Search

Field measurements of multiple offshore bar spacing were compared to theory and wave measurements to corroborate the suggestion that bar formation and spacing are controlled by standing waves in the infragravity range (0.5-5 min). Theoretical and experimental studies predict the reflection of progressive waves from a shoreline as standing waves. Associated drift in the bottom boundary layer is expected to

Andrew D. Short

1975-01-01

317

Stratigraphic Profiles for Selected Hanford Site Seismometer Stations and Other Locations  

SciTech Connect

Stratigraphic profiles were constructed for eight selected Hanford Site seismometer stations, five Hanford Site facility reference locations, and seven regional three-component broadband seismometer stations. These profiles provide interpretations of the subsurface layers to support estimation of ground motions from past earthquakes, and the prediction of ground motions from future earthquakes. In most cases these profiles terminated at the top of the Wanapum Basalt, but at selected sites profiles were extended down to the top of the crystalline basement. The composite one-dimensional stratigraphic profiles were based primarily on previous interpretations from nearby boreholes, and in many cases the nearest deep borehole is located kilometers away.

Last, George V.

2014-02-01

318

A simple high-precision Jacob's staff design for the high-resolution stratigrapher  

USGS Publications Warehouse

The new generation of high-resolution stratigraphic research depends upon detailed bed-by-bed analysis to enhance regional correlation potential. The standard Jacob's staff is not an efficient and precise tool for measuring thin-bedded strata. The high-precision Jacob's staff design presented and illustrated in this paper meets the qualifications required of such an instrument. The prototype of this simple design consists of a sliding bracket that holds a Brunton-type compass at right angles to a ruled-off staff. This instrument provides rapid and accurate measurement of both thick- or thin-bedded sequences, thus decreasing field time and increasing stratigraphic precision. -Author

Elder, W.P.

1989-01-01

319

Mapping Seabird Sensitivity to Offshore Wind Farms  

PubMed Central

We present a Geographic Information System (GIS) tool, SeaMaST (Seabird Mapping and Sensitivity Tool), to provide evidence on the use of sea areas by seabirds and inshore waterbirds in English territorial waters, mapping their relative sensitivity to offshore wind farms. SeaMaST is a freely available evidence source for use by all connected to the offshore wind industry and will assist statutory agencies in assessing potential risks to seabird populations from planned developments. Data were compiled from offshore boat and aerial observer surveys spanning the period 1979–2012. The data were analysed using distance analysis and Density Surface Modelling to produce predicted bird densities across a grid covering English territorial waters at a resolution of 3 km×3 km. Coefficients of Variation were estimated for each grid cell density, as an indication of confidence in predictions. Offshore wind farm sensitivity scores were compiled for seabird species using English territorial waters. The comparative risks to each species of collision with turbines and displacement from operational turbines were reviewed and scored separately, and the scores were multiplied by the bird density estimates to produce relative sensitivity maps. The sensitivity maps reflected well the amassed distributions of the most sensitive species. SeaMaST is an important new tool for assessing potential impacts on seabird populations from offshore development at a time when multiple large areas of development are proposed which overlap with many seabird species’ ranges. It will inform marine spatial planning as well as identifying priority areas of sea usage by marine birds. Example SeaMaST outputs are presented. PMID:25210739

Bradbury, Gareth; Trinder, Mark; Furness, Bob; Banks, Alex N.; Caldow, Richard W. G.; Hume, Duncan

2014-01-01

320

Mapping seabird sensitivity to offshore wind farms.  

PubMed

We present a Geographic Information System (GIS) tool, SeaMaST (Seabird Mapping and Sensitivity Tool), to provide evidence on the use of sea areas by seabirds and inshore waterbirds in English territorial waters, mapping their relative sensitivity to offshore wind farms. SeaMaST is a freely available evidence source for use by all connected to the offshore wind industry and will assist statutory agencies in assessing potential risks to seabird populations from planned developments. Data were compiled from offshore boat and aerial observer surveys spanning the period 1979-2012. The data were analysed using distance analysis and Density Surface Modelling to produce predicted bird densities across a grid covering English territorial waters at a resolution of 3 km×3 km. Coefficients of Variation were estimated for each grid cell density, as an indication of confidence in predictions. Offshore wind farm sensitivity scores were compiled for seabird species using English territorial waters. The comparative risks to each species of collision with turbines and displacement from operational turbines were reviewed and scored separately, and the scores were multiplied by the bird density estimates to produce relative sensitivity maps. The sensitivity maps reflected well the amassed distributions of the most sensitive species. SeaMaST is an important new tool for assessing potential impacts on seabird populations from offshore development at a time when multiple large areas of development are proposed which overlap with many seabird species' ranges. It will inform marine spatial planning as well as identifying priority areas of sea usage by marine birds. Example SeaMaST outputs are presented. PMID:25210739

Bradbury, Gareth; Trinder, Mark; Furness, Bob; Banks, Alex N; Caldow, Richard W G; Hume, Duncan

2014-01-01

321

On the stratigraphic integrity of leaf-wax biomarkers in loess paleosols  

NASA Astrophysics Data System (ADS)

Paleoenvironmental and paleoclimate reconstructions based on molecular proxies, such as those derived from leaf-wax biomarkers, in loess-paleosol sequences represent a promising line of investigation in Quaternary research. The main premise of such reconstructions is the synsedimentary deposition of biomarkers and dust, which has become a debated subject in recent years. This study uses two independent approaches to test the stratigraphic integrity of leaf-wax biomarkers: (i) long-chain n-alkanes and fatty acids are quantified in two sediment-depth profiles in glacial till on the Swiss Plateau, consisting of a Holocene topsoil and the underlying B and C horizons. Since glacial sediments are initially very poor in organic matter, significant amounts of leaf-wax biomarkers in the B and C horizons of those profiles would reflect postsedimentary root-derived or microbial contributions. (ii) Compound-specific radiocarbon measurements are conducted on n-alkanes and n-alkanoic (fatty) acids from several depth intervals in the loess section "Crvenka", Serbia, and the results are compared to independent estimates of sediment age. We find extremely low concentrations of plant-wax n-alkanes and fatty acids in the B and C horizons below the topsoils in the sediment profiles. Moreover, compound-specific radiocarbon analysis yields plant-wax 14C ages that agree well with published luminescence ages and stratigraphy of the Serbian loess deposit. Both approaches confirm that postsedimentary, root-derived or microbial contributions are negligible in the two investigated systems. The good agreement between the ages of odd and even homologues also indicates that reworking and incorporation of fossil leaf waxes is not particularly relevant either.

Häggi, C.; Zech, R.; McIntyre, C.; Zech, M.; Eglinton, T. I.

2014-05-01

322

On the stratigraphic integrity of leaf-wax biomarkers in loess-paleosols  

NASA Astrophysics Data System (ADS)

Paleoenvironmental and paleoclimate reconstructions based on molecular proxies, such as those derived from leaf wax biomarkers, in loess-paleosols sequences represent a promising line of investigation in Quaternary research. The main premise of such reconstructions is the synsedimentary deposition of biomarkers and dust, which has become a debated subject in recent years. This study uses two independent approaches to test the stratigraphic integrity of leaf-wax biomarkers: (i) Long-chain n-alkanes and fatty acids are quantified in two soil profiles in till on the Swiss Plateau. Since glacial sediments are extremely poor in organic matter, significant amounts of leaf-wax biomarkers in the lower part of those profiles would reflect post-sedimentary root-derived or microbial contributions. (ii) Compound-specific radiocarbon measurements are conducted on n-alkanes and fatty acids from several depth intervals in the loess section "Crvenka", Serbia, and the results are compared to independent estimates of sediment age. We find extremely low concentrations of plant wax n-alkanes and fatty acids below the topsoils in the soil profiles. Moreover, compound-specific radiocarbon analysis yields plant wax 14C ages that agree well with published luminescence ages and stratigraphy of the Serbian loess deposit. Both approaches confirm that post-sedimentary, root-derived or microbial contributions are negligible in the two systems investigated. The good agreement between n-alkane and fatty acid ages, as well as between odd and even homologues, further indicates that reworking and incorporation of fossil leaf-waxes is not particularly relevant either.

Häggi, C.; Zech, R.; McIntyre, C.; Eglinton, T.

2013-10-01

323

Effects of Second-Order Hydrodynamics on a Semisubmersible Floating Offshore Wind Turbine: Preprint  

SciTech Connect

The objective of this paper is to assess the second-order hydrodynamic effects on a semisubmersible floating offshore wind turbine. Second-order hydrodynamics induce loads and motions at the sum- and difference-frequencies of the incident waves. These effects have often been ignored in offshore wind analysis, under the assumption that they are significantly smaller than first-order effects. The sum- and difference-frequency loads can, however, excite eigenfrequencies of the system, leading to large oscillations that strain the mooring system or vibrations that cause fatigue damage to the structure. Observations of supposed second-order responses in wave-tank tests performed by the DeepCwind consortium at the MARIN offshore basin suggest that these effects might be more important than originally expected. These observations inspired interest in investigating how second-order excitation affects floating offshore wind turbines and whether second-order hydrodynamics should be included in offshore wind simulation tools like FAST in the future. In this work, the effects of second-order hydrodynamics on a floating semisubmersible offshore wind turbine are investigated. Because FAST is currently unable to account for second-order effects, a method to assess these effects was applied in which linearized properties of the floating wind system derived from FAST (including the 6x6 mass and stiffness matrices) are used by WAMIT to solve the first- and second-order hydrodynamics problems in the frequency domain. The method has been applied to the OC4-DeepCwind semisubmersible platform, supporting the NREL 5-MW baseline wind turbine. The loads and response of the system due to the second-order hydrodynamics are analysed and compared to first-order hydrodynamic loads and induced motions in the frequency domain. Further, the second-order loads and induced response data are compared to the loads and motions induced by aerodynamic loading as solved by FAST.

Bayati, I.; Jonkman, J.; Robertson, A.; Platt, A.

2014-07-01

324

Deep burial dolomitization driven by plate collision: Evidence from strontium-isotopes of Jurassic Arab IV dolomites from offshore Qatar  

SciTech Connect

The use of strontium-isotope ratios of dolomites to constrain timing and mechanism of diagenesis has been investigated on Jurassic Arab IV dolomites from offshore Qatar. Reservoir quality is determined by two types of dolomites, which were differentiated geochemically (cathodoluminescence, fluid inclusions, and carbon and oxygen stable isotopes): (1) stratigraphically concordant sucrosic dolomites with high porosity formed during early near-surface diagenesis (Jurassic) and (2) stratigraphically discordant cylindrical bodies of massive, porosity-destroying dolomites formed late during deep burial diagenesis (Eocene-Pliocene). Detailed Sr-isotope analysis of dolomites from the Arab IV confirms an Early Jurassic age of the sucrosic, high porosity dolomites ({sup 87}Sr/{sup 86}SR = 0.70707 for NBS 987 = 0.71024) with magnesium and strontium being derived from Jurassic seawater. Late Tertiary compressional orogeny of the Zagros belt to the north is proposed to have caused large-scale squeezing of fluids from the pore system of sedimentary rocks. A regional deep fluid flow system developed dissolving infra-Cambrian evaporites upflow and causing large-scale deep burial dolomitization downflow.

Vahrenkamp, V.C.; Taylor, S.R. (Shell Research, Rijswijk (Netherlands))

1991-03-01

325

Combined effect of tectonism, eustasy, and sediment supply on the depositional-sequence history of the western offshore, South Africa  

SciTech Connect

Interpreted seismic profiles and maps of depositional systems tracts highlight variations in basin-fill architecture and their inferred causes along western offshore South Africa. Sequence-stratigraphic concepts developed by Exxon were used to interpret 10,000 km of seismic data and logs from 31 exploration boreholes within an area of 90,000 km{sup 2}. Lower frequency second-order supercycles (5-10 Ma) are attributed to changes in the rate of subsidence and are expressed either by predominantly progradational or aggradational depositional supersequence. In addition to these long-duration, basin-wide stratigraphic packages, component depositional sequences that formed in response to third order (1-5 Ma) and higher frequency cycles vary with structural setting within the depobasin, namely depocenter, basin flanks, shelf-edge, and slope systems. High-order sequences are attributed to eustatically driven, high-frequency, base-level changes and/or localized tectonic events (i.e. slope failure, gravity faulting). Variations in the areal distribution of lowstand and shelf-margin systems tracts document lateral shifting sediment supplies and the presence of entrenched feeder-canyons linked to incised valley systems on the shelf. Many canyons, however, terminate updip and may be related to slope failure and headward erosion. The tentative correlation of regionally developed unconformities of the west coast based on microfaunal dating of a limited number of marine condensed sections points to a remarkable correspondence with the Exxon global sea-level chart.

Jungslager, E.H.A. (Soekor Ltd., Parow (South Africa))

1991-03-01

326

Divergent evolutionary processes associated with colonization of offshore islands.  

PubMed

Oceanic islands have been a test ground for evolutionary theory, but here, we focus on the possibilities for evolutionary study created by offshore islands. These can be colonized through various means and by a wide range of species, including those with low dispersal capabilities. We use morphology, modern and ancient sequences of cytochrome b (cytb) and microsatellite genotypes to examine colonization history and evolutionary change associated with occupation of the Orkney archipelago by the common vole (Microtus arvalis), a species found in continental Europe but not in Britain. Among possible colonization scenarios, our results are most consistent with human introduction at least 5100 bp (confirmed by radiocarbon dating). We used approximate Bayesian computation of population history to infer the coast of Belgium as the possible source and estimated the evolutionary timescale using a Bayesian coalescent approach. We showed substantial morphological divergence of the island populations, including a size increase presumably driven by selection and reduced microsatellite variation likely reflecting founder events and genetic drift. More surprisingly, our results suggest that a recent and widespread cytb replacement event in the continental source area purged cytb variation there, whereas the ancestral diversity is largely retained in the colonized islands as a genetic 'ark'. The replacement event in the continental M. arvalis was probably triggered by anthropogenic causes (land-use change). Our studies illustrate that small offshore islands can act as field laboratories for studying various evolutionary processes over relatively short timescales, informing about the mainland source area as well as the island. PMID:23998800

Martínková, Natália; Barnett, Ross; Cucchi, Thomas; Struchen, Rahel; Pascal, Marine; Pascal, Michel; Fischer, Martin C; Higham, Thomas; Brace, Selina; Ho, Simon Y W; Quéré, Jean-Pierre; O'Higgins, Paul; Excoffier, Laurent; Heckel, Gerald; Hoelzel, A Rus; Dobney, Keith M; Searle, Jeremy B

2013-10-01

327

Alluvial stratigraphic evidence for channel incision during the Mediaeval Warm Period on the central Great Plains, USA  

Microsoft Academic Search

Alluvial valley fills from tributaries to the upper Republican River, southwest Nebraska, USA, provide soil- and morpho-stratigraphic evidence for an episode of channel incision that occurred between c. 1100 and 800 14C yr BP, based on 11 new radiocarbon ages. This local episode of channel incision correlates with other alluvial stratigraphic studies from the central Great Plains and demonstrates regionally

J. Michael Daniels; James C. Knox

2005-01-01

328

The use of quantitative relationships and palaeoecology in stratigraphic palynology of the Murray Basin in New South Wales  

Microsoft Academic Search

Near the eastern margin of the Murray Basin in western New South Wales, thick sections of up to 170 m may be placed in the Proteacidites tuberculatus Zone, of Oligocene to Early Miocene age. In this region, this zone cannot be subdivided using conventional stratigraphic palynology, yet some stratigraphic control within the zone is necessary for groundwater exploration. Some pollen

Helene A. Martin

1984-01-01

329

Post-glacial sea-level history for SW Ireland (Bantry Bay) based on offshore evidence  

NASA Astrophysics Data System (ADS)

In recent years, progress in remote sensing techniques has helped to constrain the advance and retreat phases of the British-Irish Ice Sheet during and after the Last Glacial Maximum (LGM), both on- and offshore. However, little evidence has been collected to study the pattern of relative sea-level (RSL) change immediately after ice sheet retreat. Glacio-isostatic adjustment (GIA) models suggest a complex RSL pattern around Ireland, influenced by local and regional isostatic movements. Unfortunately, such models are poorly constrained for periods during which RSL was significantly lower than present, particularly the Late Pleistocene and Early Holocene, owing to the paucity of accurate observational data offshore. This poster presents post-LGM stratigraphic evidence from Bantry Bay (SW Ireland), one of seven areas targeted around the Irish Sea as part of a larger NERC funded project which aims to provide the first field data on the depth and age of the RSL minimum since deglaciation in the Irish Sea Basin. Data examined consists of: multibeam bathymetry and backscatter, pinger sub-bottom and vibrocores (25 sites). Notable features on the multibeam are a bluff line in the outer bay with a maximum height of 10 m in water depths of c. -80 m which forms the western edge of a large sediment lobe. The south-western boundary of this lobe is marked by a series of long (up to 22 km), parallel ridges at depths between -96 m and -131 m, with iceberg scouring evident on the offshore margin. Six seismo-stratigraphic units are interpreted from the pinger data, the most prominent of which can be traced from the inner part of the Bay to the inshore edge of the ridges. This unit sits on an erosional surface, is characterised by a turbid acoustic signature and is identified as alternating sand and clay layers with some traces of organic material and gas. Equal amounts of marine and estuarine foraminifera are present within this unit, whilst the underlying unit has a higher percentage of brackish species and the overlying unit becomes predominantly marine. Based on this evidence, we suggest that the erosional surface represents the transgressive surface, underlying intertidal sediments. Mapping the extent of this surface reveals a maximum depth of -75 m offshore, rising gradually to a depth of -30 m in the inner Bay, a profile remarkably similar to the modelled sea-level curve for the area. The long parallel ridges are interpreted to represent ice-marginal, submarine moraine ridges associated with ice retreat, behind which a glacio-marine delta formed, resulting in the large sediment lobe imaged at the mouth of Bantry Bay. Foraminifera from the proposed transgressive surface have been submitted for radiocarbon dating. Once available, these results will be used for fine-tuning the Earth and ice model parameters in the GIA model. Such adjustments could have important implications for modelled RSL curves around the Irish Sea basin.

Plets, R. M.; Callard, L.; Cooper, A.; Long, A. J.; Belknap, D. F.; Edwards, R.; Jackson, D.; Kelley, J. T.; Long, D.; Milne, G. A.; Monteys, X.; Quinn, R.

2013-12-01

330

Stratigraphic, chronological and behavioural contexts of Pleistocene Homo sapiens from Middle Awash, Ethiopia  

Microsoft Academic Search

Clarifying the geographic, environmental and behavioural contexts in which the emergence of anatomically modern Homo sapiens occurred has proved difficult, particularly because Africa lacked adequate geochronological, palaeontological and archaeological evidence. The discovery of anatomically modern Homo sapiens fossils at Herto, Ethiopia, changes this. Here we report on stratigraphically associated Late Middle Pleistocene artefacts and fossils from fluvial and lake margin

J. Desmond Clark; Yonas Beyene; Giday WoldeGabriel; William K. Hart; Paul R. Renne; Henry Gilbert; Alban Defleur; Gen Suwa; Shigehiro Katoh; Kenneth R. Ludwig; Jean-Renaud Boisserie; Berhane Asfaw; Tim D. White

2003-01-01

331

Congruence between Phylogenetic and Stratigraphic Data on the History of Life  

Microsoft Academic Search

The quality of the fossil record and the accuracy of reconstructed phylogenies have been debated recently, and doubt has been cast on how far current knowledge actually reflects what happened in the past. A survey of 384 published cladograms of a variety of animals (echinoderms, fishes, tetrapods) shows that there is good agreement between phylogenetic (character) data and stratigraphic (age)

Michael J. Benton; Rebecca Hitchin

1997-01-01

332

Seismic stratigraphic study of two Oxfordian carbonate sequences, eastern Saudi Arabia  

Microsoft Academic Search

In this case study, seismic stratigraphic interpretation techniques were used to map facies changes and develop a depositional model for two Oxfordian carbonate sequences of eastern Saudi Arabia. Well data and regional geology indicate that the two sequences, R1 and R2, were deposited on a broad carbonate platform and undergo a lateral transition from grainstone to basinal mudstone within the

G. S. Langdon; S. J. Malecek

1987-01-01

333

Stratigraphy of small shield volcanoes on Venus: Criteria for determining stratigraphic relationships and assessment of relative  

E-print Network

Stratigraphy of small shield volcanoes on Venus: Criteria for determining stratigraphic than about 20 km, are common and sometimes very abundant features on the plains of Venus. Typically plains of Venus. Did the eruption style of small shields occur repeatedly throughout the visible part

Head III, James William

334

Late Cretaceous marine transgressions in Ecuador and northern Peru: a refined stratigraphic framework  

E-print Network

Late Cretaceous marine transgressions in Ecuador and northern Peru: a refined stratigraphic the onset of compressional deformation and uplift of the Andean margin followed by a marine regression are richly fossiliferous and the terminal Cretaceous regional regression occurred later than #12;in other

Paris-Sud XI, Université de

335

Stratigraphic revision of Campanian (Upper Cretaceous) rocks in the Henry Basin, Utah  

Microsoft Academic Search

Upper Cretaceous strata in the Henry Basin of south-central Utah include a 1,575 ft thick sequence of marginal marine and continental rocks of Campanian age. Stratigraphic study of this sequence indicates the need for changes in nomenclature and boundary definitions. Paleontologic study of the same sequence provides a basis for improved interpretations of depositional environments and age. The Mancos Shale

1990-01-01

336

Stratigraphic and structural evolution of the Blue Nile Basin, Northwestern Ethiopian Plateau  

E-print Network

by Early­Late Oligocene and Quaternary volcanic rocks. This study outlines the stratigraphic and structural. The Blue Nile Basin has evolved in three main phases: (1) pre-sedimentation phase, include pre-rift peneplanation of the Neoproterozoic basement rocks, possibly during Palaeozoic time; (2) sedimentation phase

Gani, M. Royhan

337

GEOMORPHIC AND STRATIGRAPHIC ANALYSIS OF LAYERED DEPOSITS IN TERBY CRATER, MARS. S. A. Wilson1  

E-print Network

GEOMORPHIC AND STRATIGRAPHIC ANALYSIS OF LAYERED DEPOSITS IN TERBY CRATER, MARS. S. A. Wilson1 of intriguing landforms banked along the northern edge of Terby Crater located on the northern rim of Hellas (~28°S, 287°W). Landforms within this crater include north-trending troughs and ridges, a remarkable 2

Howard, Alan D.

338

OCEANOGRAPHY Stratigraphic Distribution of Amino Acids in Peats from Cedar Creek  

E-print Network

LIMNOLOGY AND OCEANOGRAPHY April 1959 VOLUME IV NUMBER 2 Stratigraphic Distribution of Amino Acids. MILLERS University of Minnesota, Minneapolis ABSTRACT The concentration of several alpha-amino acids. Seven amino acids are consistently present in the natural accumulations: glycine, aspartic acid

Minnesota, University of

339

Stratigraphic succession and UPb geochronology from the Teslin suture zone, south-central Yukon  

Microsoft Academic Search

A lithologic succession is recognized in tectonites of the eastern Teslin suture zone in south-central Yukon. Metagraywacke and quartzite, marble, mafic metavolcanics, and interbedded metagraywacke and argillite outcrop on both limbs of an upright northwest-trending syncline at Little Salmon Lake. A body of equigranular granodiorite intrudes the basal stratigraphic units. The granodiorite and its host sediments were penetratively deformed during

Douglas H. Oliver; James K. Mortensen

340

Neoproterozoic variations in the C-isotopic composition of seawater: stratigraphic and biogeochemical implications  

NASA Technical Reports Server (NTRS)

The recent proliferation of stratigraphic studies of delta 13C variation in carbonates and organic C in later Neoproterozoic and basal Cambrian successions (approximately 850-530 Ma) indicates a strong oscillating trend in the C-isotopic composition of surface seawater. Alone, this trend does not adequately characterize discrete intervals in Neoproterozoic time. However, integrated with the vectorial signals provided by fossils and Sr-isotopic variations, C isotope chemostratigraphy facilitates the interbasinal correlation of later Neoproterozoic successions. Results of these studies are evaluated in terms of four stratigraphic intervals: (1) the Precambrian/Cambrian boundary, (2) the post-Varanger terminal Proterozoic, (3) the late Cryogenian, and (4) the early Cryogenian. Where biostratigraphic or radiometric data constrain the age of Neoproterozoic sedimentary sequences, secular variations in C and Sr isotopes can provide a level of stratigraphic resolution exceeding that provided by fossils alone. Isotopic data place strong constraints on the chemical evolution of seawater, linking it to major tectonic and paleoclimatic events. They also provide a biogeochemical framework for the understanding of the initial radiation of macroscopic metazoans, which is associated stratigraphically, and perhaps causally, with a global increase in the burial of organic C and a concomitant rise of atmospheric O2.

Kaufman, A. J.; Knoll, A. H.

1995-01-01

341

Stratigraphic condensation of marine transgressive records: Origin of major shell deposits in the Miocene of Maryland  

Microsoft Academic Search

Cyclic stratigraphic sequences in shallow marine records are commonly charaterized by a condensed transgressive lag at the base of thicker, shallowing-upward facies. The standard actualistic model for these thin fossiliferous lags, by which most of the shelf is starved owing to coastal trapping of sediment and fossils are suspected of being reworked because of the association with an erosional ravinement,

Susan M. Kidwell

1989-01-01

342

Applications of the SHDT stratigraphic high resolution dipmeter to the study of depositional environments  

Microsoft Academic Search

The new SHDT Stratigraphic High Resolution Dipmeter Tool has been specifically designed to treat sedimentary problems. This is achieved chiefly thanks to correlations done on two dip curves taken horizontally 3 cm. apart on each of the four tool arm pads, yielding a density of results up to one full order of magnitude higher than with conventional hardware and processing.

D. A. Seeburger; Y. Chauvel; A. C. Orjuela

1984-01-01

343

Regional correlations in the South Caspian Sea -implications for stratigraphic nomenclature  

SciTech Connect

Regional Correlations in the South Caspian Sea - Implications for Stratigraphic Nomenclature Detailed sequence boundary correlations in the South Caspian sea have led to a better understanding of the relationships between stratigraphic units identified in wells throughout the basin. With the aid of synthetic seismograms, used to tie the logs to the seismic data, lithologic units have been identified seismically and have been mapped across the basin. The synthetic seismograms were created from pseudo-sonic logs which were transformed from resistivity logs with the Faust equation. Checkshots and VSP surveys supplied the velocity control. The sequence boundary correlations revealed substantial facies changes across the basin and led to the creation of a new stratigraphic correlation chart which relates local formation names to their time correlative boundaries. A recognition of these facies changes has led to a better understanding of the lithologic relationships within the basin, the depositional history of the basin, and the source and distribution of potential reservoir sands. Previous well log correlations, made primarily by matching tops of sand and shale sequences, frequently crossed sequence boundaries mapped from seismic data. Lithologic units, deposited under similar geologic conditions, often looked the same but were not time equivalent. Seismic sequence analyses have shown that tectonic movements, as evidenced by rising domes, created barriers to sediment distribution and led to pronounced thickness changes on opposite sides of a high. New log correlations, incorporating these concepts, are helping to unravel the complex structural and stratigraphic history of the South Caspian Sea.

Murphy, J. [Chevron, San Ramon, CA (United States)] Rukhsara, K. [State Oil Company, Baku (Kazakhstan)

1995-08-01

344

Quarter Wave Resonances Between Targets and Stratigraphic Interfaces Within GPR Profiles of Shallow Frozen Lakes  

Microsoft Academic Search

Resonances commonly appear within GPR reflection profiles. They can be caused by the target itself or by reverberation between a target and a stratigraphic interface that defines a high contrast in permittivity. The most common interface is the ground surface. I discuss resonances that occur at depth beneath shallow, frozen lakes located on an artillery and bombing range in interior

S. A. Arcone

2006-01-01

345

Inorganic geochemistry of Devonian shales in southern West Virginia: geographic and stratigraphic trends  

SciTech Connect

Samples of cuttings from twenty-one wells and a core from a single well in southern West Virginia were analyzed for major and minor elements: silicon, aluminum, iron, magnesium, calcium, sodium, titanium, phosphorus, manganese, sulfur, zinc, and strontium. Stratigraphic and geographic controls on elemental abundances were studied through canonical correlations, factor analyses, and trend surface analyses. The most abundant elements, silicon and aluminum, show gradual trends through the stratigraphic column of most wells, with silicon increasing and aluminum decreasing up-section. Other elements such as calcium, sulfur, and titanium change abruptly in abundance at certain stratigraphic boundaries. Important geographic trends run east-west: for instance, one can see an increase in sulfur and a decrease in titanium to the west; and a decrease in silicon from the east to the central part of the study area, then an increase further west. Although observed vertical trends in detrital minerals and geographic patterns in elemental abundances agree with the accepted view of a prograding delta complex during Late Devonian time, geographically-local, time restricted depositional processes influenced elemental percentages in subsets of the wells and the stratigraphic intervals studied. The black shales of lower Huron age do not represent simply a return of depositional conditions present in the earlier Rhinestreet time; nor do the gray shales of the Ohio Shale represent the same environmental conditions as the Big White Slate.

Hohn, M.E.; Neal, D.W.; Renton, J.J.

1980-04-01

346

Regional stratigraphic scheme and paleogeographic events of the late Miocene, Pliocene and Quaternary in Armenia  

Microsoft Academic Search

Regional Upper Cenozoic stratigraphic schemes are available from several summarizing works [2?5, 7?10]. In the present communication, these materials are discussed with consideration of new data on upper Miocene, Pliocene, and Quaternary stratigraphy and paleogeography of Armenia, which make it possible to significantly refine the scheme for Armenia. The scheme is largely based on reference sections of the large Sevan,

Yu. V. Sayadyan

2006-01-01

347

Regional paleoclimatic and stratigraphic implications of paleosols and fluvial/overbank architecture in the Morrison Formation  

E-print Network

Regional paleoclimatic and stratigraphic implications of paleosols and fluvial/overbank (Upper Jurassic) from the Western Interior and Colorado Plateau regions occur in fluvial/overbank times of relatively slow or no accumulation of sediment. During these times, the land surface and near

Nicoll, Kathleen

348

Chemical fingerprinting of stratigraphic surfaces to refine reservoir architecture and differentiate fluid flow regimes  

SciTech Connect

The variable development of depositional cycles within hydrocarbon reservoirs, especially reservoirs contained within platform carbonates, can have a profound influence on fluid flow. These cycles can be recognized in core and logs and should form the basis of subsurface geologic models. When placed into a sequence stratigraphic framework, cycle variability can be predicted. We herein investigate the use of chemostratigraphy to refine a reservoir-scale stratigraphic framework and demonstrate the influence of this framework on fluid flow. Using cores and outcrops of the Permian San Andres Formation in the Guadalupe Mountains of southeastern New Mexico, permeability distribution and waterflood response was modeled for a small-scale carbonate sequence (105 no thick) containing variably developed depositional cycles that formed in a carbonate ramp setting. Cross-sectional fractal permeability fields, used in simulated waterfloods, demonstrate sensitivities of oil recovery and overall injection rare to the stratigraphic framework. Major, minor and trace element variation measured on 44 interval composites from core, using a combination of techniques including inductively coupled plasma (ICP) and mass spectrometry, characterize and fingerprint important stratigraphic surfaces (sequence boundaries, cycle boundaries, and flooding surfaces). Less distinct cycles below this surface we characterized by compartmentalized flow and poor vertical sweep efficiency, whereas well-developed cycles above are characterized in our analog by a potential for early water breakthrough and relatively high vertical sweep efficiencies.

Eisenberg, R.A.; Harris, P.M. [Chevron Petroleum Technology Co., La Habra, CA (United States)

1995-08-01

349

Integration of the stratigraphic aspects of very large sea-floor databases using information processing  

USGS Publications Warehouse

Information-processing methods are described that integrate the stratigraphic aspects of large and diverse collections of sea-floor sample data. They efficiently convert common types of sea-floor data into database and GIS (geographical information system) tables, visual core logs, stratigraphic fence diagrams and sophisticated stratigraphic statistics. The input data are held in structured documents, essentially written core logs that are particularly efficient to create from raw input datasets. Techniques are described that permit efficient construction of regional databases consisting of hundreds of cores. The sedimentological observations in each core are located by their downhole depths (metres below sea floor - mbsf) and also by a verbal term that describes the sample 'situation' - a special fraction of the sediment or position in the core. The main processing creates a separate output event for each instance of top, bottom and situation, assigning top-base mbsf values from numeric or, where possible, from word-based relative locational information such as 'core catcher' in reference to sampler device, and recovery or penetration length. The processing outputs represent the sub-bottom as a sparse matrix of over 20 sediment properties of interest, such as grain size, porosity and colour. They can be plotted in a range of core-log programs including an in-built facility that better suits the requirements of sea-floor data. Finally, a suite of stratigraphic statistics are computed, including volumetric grades, overburdens, thicknesses and degrees of layering. ?? The Geological Society of London 2006.

Jenkins, C.; Flocks, J.; Kulp, M.

2006-01-01

350

Orbit and bundle stratification of controllability and observability matrix pairs in StratiGraph  

E-print Network

of orbits and bundles of general matrices and matrix pencils is presented by Edelman, Elmroth, and K°agstr¨omOrbit and bundle stratification of controllability and observability matrix pairs in StratiGraph Erik Elmroth, Pedher Johansson, Stefan Johansson, and Bo K°agstr¨om Department of Computing Science

Johansson, Stefan

351

Orbit and bundle stratification of controllability and observability matrix pairs in StratiGraph  

E-print Network

Orbit and bundle stratification of controllability and observability matrix pairs in StratiGraph Erik Elmroth, Pedher Johansson, Stefan Johansson, and Bo K°agstr¨om Department of Computing Science orbit and bundle closure hierarchies. 1 Introduction Computing the canonical structure of a matrix

Kågström, Bo

352

Sedimentological and sequence stratigraphic analysis of Carboniferous deposits in western Libya: Recording the sedimentary response of the northern Gondwana margin to climate and sea-level changes  

NASA Astrophysics Data System (ADS)

Detailed sedimentological and sequence stratigraphic analysis of Carboniferous (Tournaisian to Moscovian) strata exposed in the north-western Murzuq Basin and southern Ghadames Basin, western Libya, provides new insights into the sedimentary response of the northern Gondwana margin to climate and sea-level change. The Lower Carboniferous Marar and Assedjefar Formations can be divided into five depositional sequences of 3rd order. In total 27 facies types are defined, grouped into four facies associations: offshore shales, shallow marine clastics, fluvial sandstones and marine carbonates. The bulk of the Lower Carboniferous interval is dominated by an alternation of offshore shales and shallow marine clastics, which were deposited during the transgressive and highstand systems tracts. The clastic deposits mostly consist of laterally persistent coarsening and thickening upward cycles with a common succession from basal hummocky cross-stratified sandstones to ripple-laminated sandstones, capped by multidirectional cross-stratified sandstones. Within the lowstand systems tracts, lenticular sandbodies have been identified, which vary in thickness from 1.5 m (ca. 40 m wide) to 50 m (ca. 1.5 km wide). These are interpreted to be fluvial channel complexes based on their geometry, erosive base, and presence of thick stacked sandstones with unidirectional planar and trough cross-bedding, the absence of bioturbation and occurrence of land plant fragments. These channel complexes mostly cut down into offshore shales, and are interpreted to be bound at the base by sequence boundaries. Palaeogeographic maps generated for each lowstand system show the location and palaeoflow direction of these fluvial channel complexes. They are interpreted to represent large incised valleys filled with thick fluvial sandstones. Their identification and distribution indicates repeated exposure of large areas of western Libya, most-likely controlled by major eustatic sea-level changes. The Assedjefar Formation exibits a gradual decrease in coarse clastic sediment supply throughout the Serpukhovian and by the Bashkirian and Moscovian during the deposition of the Dembaba Formation a carbonate depositional system was established. Limestones are dominantly made up of a heterozoan fauna (brachiopods, crinoids, bryozoans, gastropods) and are mostly preserved as shallow marine storm and coastal deposits. It is hypothesised that a local increase in aridity and/or the gradual erosion and decreasing topography of the hinterland mountains, with the resulting reduction in discharge, controlled this shift from clastic to carbonate deposition. Available data indicate that the Murzuq Basin was interconnected with the Ghadames Basin at this time and is a postdepositional basin with respect to the Carboniferous interval. The sedimentological and sequence stratigraphic data from the present study offer new insights into the depositional setting and facies distribution in the Carboniferous, and the recognition of major incised fluvial systems has significant implications in the search for potential Carboniferous hydrocarbon reservoirs in the Murzuq, Ghadames, and Illizi Basins.

Fröhlich, Sebastian; Petitpierre, Laurent; Redfern, Jonathan; Grech, Paul; Bodin, Stéphane; Lang, Simon

2010-06-01

353

Glacially Generated Overpressure Offshore Massachusetts, USA: Integration of Full Seismic Waveform Inversion and Overpressure Modeling  

NASA Astrophysics Data System (ADS)

Localized, high-amplitude reflections, overlying a late Pleistocene glacial erosion surface 100 km offshore Massachusetts, USA, have lower compressional wave velocities of up to 200 m/s compared to adjacent sediments of equal depth. This may be the result of lower effective stress from overpressures as high as 1 MPa. To investigate the origin of these low velocity zones, we compare the detailed velocity structure across the high-amplitude regions to adjacent, undisturbed regions through a full waveform inversion, and we forward model the effective stress and overpressure. We relate the full waveform inversion velocities to effective stress with a power-law model. This model predicts effective stresses are 0.6 MPa at 250 m below the sea floor, which equates to an overpressure of 1.0 MPa. To help understand the overpressure source, we model the pressure response to erosion, glacial loading, and sedimentation in 1D. Preliminary models show that late Pleistocene glaciations, including the Last Glacial Maximum (LGM), and rapid sedimentation from glacial lake drainage may be important mechanisms for the generation of the localized regions of high overpressure. Our geophysical observations and interpretations suggest overpressure exists offshore today. Our forward models predict that this overpressure originated during the LGM due to pore pressure generation from rapid loading by glacial ice, however these overpressures are dissipating in the modern, low sedimentation rate environment. These shallow overpressures provide a mechanism to explain the SGD inferred along the Northern Atlantic continental shelf. Our results also provide physical-property observables, specific to location, that can constrain ongoing 3D numerical modeling efforts to deterministically predict the hydrologic history of the continental shelf sediments based on detailed stratigraphic and ice-sheet evolution.

Siegel, J. E.; Lizarralde, D.; Dugan, B.; Person, M. A.

2012-12-01

354

Topographic Growth, the Development of Rivers and Implications for the Marine Stratigraphic Record in SE Asia (Invited)  

NASA Astrophysics Data System (ADS)

The sediments accumulating in the marginal seas of Southeast Asia are largely delivered from the major rivers that flow from the eastern flank of the Tibetan Plateau. At the regional scale the rate of sediment delivery is controlled by the intensity of the summer monsoon, but in individual deltas the composition of sediment and rates of sedimentation are also affected by headwater capture. Recent data now indicate that significant transfer drainage between rivers occurred around the end of the Oligocene-early Miocene (~24 Ma). This key period reflects the start of significant uplift in southeastern Tibet, coupled with extension and subsidence in the marginal seas of eastern Asia driven by the rollback of the Pacific plate. U-Pb ages of zircon sand grains in the Yangtze River show that this system was close to its present configuration before 23 Ma, correlating with large-scale change in the Red River during the latter part of the Oligocene. At the same time, the Irrawaddy loses its connection with the Yarlung Tsangpo, which dates back to shortly after India-Asia collision. The Yarlung Tsangpo together with the Indus appears to be unique in forming in the collisional suture between Asia (or an intraoceanic arc) and India shortly after 50 Ma. Once these two rivers are established in the suture zone it is impossible to disrupt their flow as a result of tectonically driven uplift, but it is only in Southwest Asia that the marine record would span the entire Cenozoic history of uplift and erosion, as preserved in the Indus Fan. In contrast, the more gradual tilting of Eastern Asia towards the east through the Cenozoic has resulted in the large-scale disruption noted in the deltas. Diversion of large volumes of clastic sediment from one delta to another has implications for how we interpret the deep-sea sediment record in each location and is of commercial interest in hydrocarbon exploration in changing the availability of reservoir sands on continental margins in ways that are unrelated to either of the local tectonics or regional climate change. Only the Pearl River appears to be unaffected by the evolving topography. Provenance in its offshore basins indicates a constant source in southern China, albeit one that expands gradually inland after the rifting of the South China Sea, but without any major capture events on the scale seen in other Asian river systems. Presently the origin of the Mekong is the most enigmatic, because the marine stratigraphic record suggests its initiation during the late Miocene, at least in the present position.

Clift, P. D.; Zheng, H.

2013-12-01

355

Bedout basement rise, offshore northwestern Australia: evidence of an unshocked mafic volcanic hyaloclastite volcanic breccia  

NASA Astrophysics Data System (ADS)

Core samples from Bedout-1 (3035.8-3044.95 m.), Bedout basement rise, offshore northwestern Australia, were examined by optical microscopy, SEM, EDS and WDS spectrometry. At this stratigraphic depth level Becker et al. (2004) interpret cryptocrystalline alteration zones around and within plagioclase in terms of shock-induced transformation of feldspar into diaplectic maskelynite glass _u postulating a ~200 km-large impact structure and thereby an impact connection of the Permian-Triassic boundary mass extinction. However, the breccia is dominated by fragments of microlitic basalt and ophitic-textured dolerite with well preserved igneous textures, showing no evidence of shock metamorphism. Euhedral pseudomorphs of chlorite and amphibole, probably after pyroxene, protrude into or are enveloped by euhedral albite-twinned calcic plagioclase (andesine to bytownite). Minor phases include euhedral ilmenite needles and subhedral magnetite grains. Plagioclase is altered by cryptocrystalline albite and microcrystalline albite-chlorite matrix along crystal boundaries, along twin lamella and within internal oscillatory crystal zones, consistent with burial metamorphosed hydrovolcanic basalts and spilites (e.g. Amstutz, 1974). The volcanic fragments are set within, and injected by, microcrystalline intergranular mesostasis of mixed mineral fragments and volcanic meta-glass. Becker et al. (2004) refer to the breccia in part as product of Mg-rich sediments (e.g. dolomites). However, apart from the pristine igneous textures of the breccia, the transition element levels (chlorite in dolerite fragment "C Ni 97-160 ppm; Co 75-152 ppm; Cu 69-204 ppm; mesostasis "C Ni 29-45 ppm; Co 18-52 ppm; Cu 26-110 ppm) are consistent with Fe-rich basalts but exceed common abundances in carbonates and marls (BVTP, 1981; Wedepohl, 1978). No shock metamorphic features, such as planar deformation features (PDF), are observed in the feldspar or in any other phases. No criteria for discriminating maskelynite and volcanic meta-glass are indicated by Becker et al. (2004). As PDF formation (10-35 GPa) necessarily precedes diaplectic transformation into maskelynite (35-45 GPa) (French, 1998), a presence of maskelynite is inconsistent with the absence of PDF in the plagioclase _u a phase prone to the development of shock effects (e.g. Mory, 2000). Little evidence exists for the hydrothermal activity which typically follows impact events. However, thanks to a partial development of a rim syncline-like structure in Triassic sediments around the Bedout rise, further testing of the origin of this remarkable structure is warranted. Amstutz, G.C., 1974, Spilites and Spilitic Rocks, Springer-Verlag, Berlin; Becker, L. et al., 2004, Science Express, 13.5.04; BVSP - Basaltic Volcanism Study Project, 1981, Pergamon; French, B.M., 1998, Traces of Catastrophe, Lunar and Planetary Contributions 954; Mory et al., 2000, Earth and Planetary Science, 177, 119-128; Wedepohl, K.H., Handbook of Geochemistry, Springer-Verlag, 1978.

Glikson, A.

2004-12-01

356

The offshore record of variable Cenozoic sediment flux from Western Scandinavia  

NASA Astrophysics Data System (ADS)

The rates of sediment input to the North Sea and the Norwegian Shelf varied significantly during the Cenozoic. During Paleocene and Eocene times The Shetland Platform and Scottish Highlands were the main sediment sources, while with the onset of the Oligocene more sediment was coming from the Scandinavian shield (Millennium Atlas). In general, the western Scandinavian sediment production rate increased from south to north, with more than 500m of Oligocene deposits in the central and eastern North Sea (Huuse et al., 2001) to as much as 2000m of Pliocene deposits in the Møre basin (Dehls et al., 2002). This is believed mainly to be a consequence of varying erosion rates and/or changes in sediment catchments in Western Scandinavia. This has previously been interpreted in terms of variable tectonic uplift of the area caused by a hitherto unknown tectonic agent; Neither crustal shortening and thickening or magmatic underplating onshore, as well as other plate tectonic mechanisms, are compatible with observations. A dense grid of seismic data and well logs from numerous boreholes in the research area allow to estimate the rate of deposition of matrix mass and to localize main areas of sediment outpour as a function of time. Here we present semi-quantitative maps of sediment flux from western Scandinavia during subsequent epochs of the Cenozoic and discuss possible explanations. After a warm and ice-free Cretaceous period, the climate remained mild during Paleocene and Eocene times. On the Eocene-Oligocene greenhouse-icehouse transition the sediment yield of the Scandinavian shield increased. Furthermore, recent results (Heilmann-Clausen and van Simayes, 2005; Nielsen et al., 2008; Sliwinska et al., 2008) show a correlation between climate fluctuations and sequence stratigraphic surfaces and lithological changes in the North Sea. Based on this evidence we suggest that a rapid cooling at the beginning of Oligocene (Oi-1 glaciation, Zachos et al., 2001) changed the erosional regime in western Scandianvia from fluvial (which is inefficient in tectonically stable settings, regardless of the amount of precipitation - Von Blanckenburg, 2005) to glacial. As, furthermore, glacial erosion (the glacial "buzzsaw" Mitchell and Montgomery, 2006; Brozovic et al., 1997; Pedersen et al, 2008) and periglacial processes (Anderson, 2002) are known to possess the potential for producing characteristic low-relief accordant landscapes at high elevation, this hypothesis also provides and alternative to understanding flattish landscape elements in the western Scandinavian highlands, which conventionally have been explained as remnants of uplifted peneplains previously graded to sea level (the Davisian cyclic landscape evolution model). Therefore, given the Eocene-Oligocene greenhouse-icehouse transition, which must have increased the importance of glacial and periglacial erosion and transport processes in the highlands of western Scandinavia, a hypothesis of climate control on erosional and depositional history of western Scandinavia and adjacent sedimentary basins emerges. This hypothesis is to be tested using the present results. Estimation of offshore matrix mass will be the basis for reconstruction of the development of source areas with use of mathematical models of landscape evolution.

Goledowski, B.; Nielsen, S. B.; Calusen, O. R.

2009-04-01

357

Eolian dune, interdune, sand sheet, and siliciclastic Sabkha sediments of an offshore prograding Sand Sea, Dhahran area, Saudi Arabia  

SciTech Connect

An offshore prograding sand sea exists along portions of the Arabian Gulf coastline near Dhahran, Saudi Arabia. In this region, sediments of eolian dune, interdune, sand sheet, and siliciclastic sabkha intercalate with marine deposits. This depositional setting is characterized by strong offshore winds which supply abundant sand to the coastline, and cause at present time the outbuilding of the dune system. This quartz-detrital dominant setting contrasts markedly with the carbonate dominant setting resulting from onshore winds in the Trucial Coast area to the south. The broad intercalation of eolian and marine deposits which results creates ideal potential for subregional stratigraphic petroleum traps, due to pinch-out of porous and permeable dune sands into impermeable marine mudstones. Within the eolian system itself are potential reservoir rocks (dunes), sources (organic-rich sabkha and interdune deposits), and seals (zones of early cementation in all deposits). Early cementation is very common in all facies of the eolian sand sea. The early cementation occurs owing to (1) soil formation, (2) deposition of pore-filling gypsiferous cements from saturated solutions near water table, and (3) addition of sand-size windblown evaporitic material to sands downwind of sabkhas.

Fryberger, S.G.; Al-Sari, A.M.; Clisham, T.J.

1983-02-01

358

Eolian Dune, interdune, sand sheet, and Siliciclastic Sabkha sediments of an offshore prograding Sand Sea, Dhahran Area, Saudi Arabia  

SciTech Connect

An offshore prograding sand sea exists along portions of the Arabian Gulf coastline near Dhahran, Saudi Arabia. In this region, sediments of eolian dune, interdune, sand sheet, and siliciclastic sabkha intercalate with marine deposits. This depositional setting is characterized by strong offshore winds which supply abundant sand to the coastline, and cause at present time the outbuilding of the dune system. This quartz-detrital dominant setting contrasts markedly with the carbonate dominant setting resulting from onshore winds in the Trucial Coast area to the south. The broad intercalation of eolian and marine deposits which results creates ideal potential for subregional stratigraphic petroleum traps, due to pinch-out of porous and permeable dune sands into impermeable marine mudstones. Within the eolian system itself are potential reservoir rocks, sources, (organic-rich sabkha and interdune deposits), and seals (zones of early cementation in all deposits). Early cementation is very common in all facies of the eolian sand sea. The early cementation occurs owing to (1) soil formation, (2) deposition of pore-filling gypsiferous cements from saturated solutions near water table, and (3) addition of sand-size windblown evaporitic material to sands downwind of sabkhas.

Fryberger, S.G.; Al-Sari, A.M.; Clisham, T.J.

1983-02-01

359

New technology emphasizes international offshore effort  

SciTech Connect

While the offshore industry is focusing its major development efforts on the deeper waters of the US Gulf, West Africa and Brazil, technology has not stood still in the world`s many other established and frontier offshore development areas. These selected items drawn from contributions by UK companies and a major joint-venture development in Eastern Canada emphasize this effort. Included here are: (1) announcement of a major six-field, 3 Tcf gas development off Nova Scotia`s Sable Island and award of two drilling contracts; (2) a comprehensive study of mobile production units in the UK by Smith Rea Energy Analysts; (3) four applications of an option to high-pressure swivels on an FPSO with multiple subsea inlet lines; (4) a contract to supply a DC bus drive for 17 ESPs on Texaco`s Captain field; and (5) review of an environmental study of the Falkland Islands in preparation for exploration activity.

NONE

1997-07-01

360

Locating Microseism Sources in Offshore Southern California  

NASA Astrophysics Data System (ADS)

We use the broadband stations from the S. California network to locate the apparent origin of secondary microseisms energy (5-8 Hz band). The procedure is to grid the offshore region and using each grid point as the source point, predict the response of a Rayleigh wave at each station. These predicted waveforms are then correlated with the data over a time window that is typically a 1/2 hour in length and composited at the grid point. The length of the time window controls a tradeoff between the spatial-temporal resolution of the sources and the robustness on the image. The procedure is valid for multiple sources. This results show that during periods of high microseism activity the sources are distinct at several locations in a region approximately 50-100 km offshore. For an 11/09/2002 Southern Ocean storm, for example, two zones parallel to each other and perpendicular to the coast are imaged.

Tian, X.; Clayton, R. W.

2007-12-01

361

Perspectives of offshore geothermal energy in Italy  

NASA Astrophysics Data System (ADS)

Italy is the first European and world's fifth largest producer of geothermal energy for power generation which actually accounts for less than 2% of the total electricity production of the country. In this paper after a brief introduction to the basic elements of high-enthalpy geothermal systems, we discuss the potentialities represented by the submarine volcanoes of the South Tyrrhenian Sea. In particular we focus on Marsili Seamount which, according to the literature data, can be considered as a possible first offshore geothermal field; then we give a summary of the related exploitation pilot project that may lead to the realization of a 200MWe prototype power plant. Finally we discuss some economic aspects and the development perspectives of the offshore geothermal resource taking into account the Italian energy framework and Europe 2020 renewable energy target.

Armani, F. B.; Paltrinieri, D.

2013-06-01

362

Offshore distributional patterns of Hawaiian fish larvae  

Microsoft Academic Search

An analysis of ichthyoplankton samples based on relative abundance reveals pronounced inshore\\/offshore distributional gradients for most Hawaiian fish larvae. Larvae of pelagic bay species are found almost exclusively in semi-enclosed bays and estuaries. Larvae of pelagic neritic species are more or less uniformly distributed with distance from shore. The larvae of reef species with non-pelagic eggs are most abundant close

J. M. Leis; J. M. Miller

1976-01-01

363

CATHODIC PROTECTION RETROFIT OF AN OFFSHORE PIPELINE  

Microsoft Academic Search

Cathodic protection (CP) anodes and corrosion coating on two offshore pipelines were damaged during deep water installation. In-situ methods for deep-water inspection and repair of the pipelines` CP and coating systems were developed and used. High-pressure natural gas Pipeline. A design was 5.6 miles of 8.625 in. OD by 0.406 in. W.T. API SL, Grade X-42, seamless line pipe. Pipeline

Robert Winters; Alan Holk

1997-01-01

364

Offshore production riser with flexible connector  

SciTech Connect

A central pipe riser support structure is connected to an underwater offshore base member by means of a gimbal joint. Vertical flow lines run parallel to the central riser and are supported by support means connected thereto. The lowermost support of each flow line is formed by a guide sleeve allowing at most a 3/sup 0/ deviation between the central axis of the guide sleeve and the central axis of the flow line.

Blomsma, E.C.; Holtslag, P.T.

1981-06-16

365

Designing Australia's North West Shelf offshore pipeline  

SciTech Connect

Design studies for the offshore pipeline system for the North West Shelf project in Australia commenced in the early 1970s. The trunkline from the North Rankin A platform to shore has recently been completed as the first part of the offshore pipeline system for the North West Shelf project. This pipeline originates from the platform in a water depth of 125 m (410 ft), enters the mouth of Mermaid Sound, and terminates just south of Withnell Bay on the Burrup Peninsula, on the North West coastline of Western Australia. The pipeline is 1,016 mm (40 in.) in diameter and 134.2 km (83.4 miles) long. It will operate in two-phase flow, bringing both gas and condensate to an onshore plant near its landfall. A slugcatcher has been constructed within the plant to receive liquidhydrocarbon slugs from the pipeline. The trunkline to shore will initially serve only the one offshore platform and operate at about 25% of its capacity to supply the Western Australian domestic gas market. The domestic gas plant on the Burrup Peninsula is being constructed by Woodside to produce pipeline-quality gas for delivery to the State Energy Commission and condensate for shipment by coastal tankers.

Seymour, E.V.; Craze, D.J.; Ruinen, W.

1984-05-07

366

Development and application of oil-spill risk assessment model for offshore pipeline  

NASA Astrophysics Data System (ADS)

To the potential oil-spill risk caused by offshore pipeline more attention has been paid after the Dalian oil spill incident from oil-pipeline explosion. Since then an issue about how to prevent and control the sudden oil-spill from the offshore pipeline has been raised. In this paper, we proposed an optimized model to analyze the main causes (probability) of spill and the consequence with the fuzzy comprehensive assessment model. Considering the complicated assessment process for oil-spill, the assessment factor system involving the spill probability and consequence was established based on the operative manual and statistic leakage/damage data of offshore pipeline in order to estimate the integrated spill risk score automatically. The evaluated factors of spill probability could be grouped into five aspects: corrosion, fatigue, national damage, third party, and operational fault; the consequence evaluated factors of spill included hazard of oil and impact-controlling capability. With some modifications based on experts' opinions, each of the evaluated factors in our work was developed with a relative weight and evaluation criterion. A test example for an offshore pipeline in the Bohai waters was described to show how the model can be used for an actual case in more detail. By using the oil-spill risk assessment model, it is easy to determine the risk level associated with the ongoing activity and management level and hence to take the risk mitigation action immediately.

Lu, Yan; Wang, Jia; Wei, Wenpu; Yang, Yong; An, Wei

2014-06-01

367

Integration of offshore wind farms through high voltage direct current networks  

NASA Astrophysics Data System (ADS)

The integration of offshore wind farms through Multi Terminal DC (MTDC) networks into the GB network was investigated. The ability of Voltage Source Converter (VSC) High Voltage Direct Current (HVDC) to damp Subsynchronous Resonance (SSR) and ride through onshore AC faults was studied. Due to increased levels of wind generation in Scotland, substantial onshore and offshore reinforcements to the GB transmission network are proposed. Possible inland reinforcements include the use of series compensation through fixed capacitors. This potentially can lead to SSR. Offshore reinforcements are proposed by two HVDC links. In addition to its primary functions of bulk power transmission, a HVDC link can be used to provide damping against SSR, and this function has been modelled. Simulation studies have been carried out in PSCAD. In addition, a real-time hardware-in-the-loop HVDC test rig has been used to implement and validate the proposed damping scheme on an experimental platform. When faults occur within AC onshore networks, offshore MTDC networks are vulnerable to DC overvoltages, potentially damaging the DC plant and cables. Power reduction and power dissipation control systems were investigated to ride through onshore AC faults. These methods do not require dedicated fast communication systems. Simulations and laboratory experiments are carried out to evaluate the control systems, with the results from the two platforms compared..

Livermore, Luke

368

Calibration and Validation of a Spar-Type Floating Offshore Wind Turbine Model using the FAST Dynamic Simulation Tool: Preprint  

SciTech Connect

In 2007, the FAST wind turbine simulation tool, developed and maintained by the U.S. Department of Energy's (DOE's) National Renewable Energy Laboratory (NREL), was expanded to include capabilities that are suitable for modeling floating offshore wind turbines. In an effort to validate FAST and other offshore wind energy modeling tools, DOE funded the DeepCwind project that tested three prototype floating wind turbines at 1/50th scale in a wave basin, including a semisubmersible, a tension-leg platform, and a spar buoy. This paper describes the use of the results of the spar wave basin tests to calibrate and validate the FAST offshore floating simulation tool, and presents some initial results of simulated dynamic responses of the spar to several combinations of wind and sea states.

Browning, J. R.; Jonkman, J.; Robertson, A.; Goupee, A. J.

2012-11-01

369

The public's trust in scientific claims regarding offshore oil drilling.  

PubMed

Our study examines how individuals decide which scientific claims and experts to believe when faced with competing claims regarding a policy issue. Using an experiment in a public opinion survey, we test the source content and credibility hypotheses to assess how much confidence people have in reports about scientific studies of the safety of offshore oil drilling along the California coast. The results show that message content has a substantial impact. People tend to accept reports of scientific studies that support their values and prior beliefs, but not studies that contradict them. Previous studies have shown that core values influence message acceptance. We find that core values and prior beliefs have independent effects on message acceptance. We also find that the sources of the claims make little difference. Finally, the public leans toward believing reports that oil drilling is riskier than previously believed. PMID:21553598

Carlisle, Juliet E; Feezell, Jessica T; Michaud, Kristy E H; Smith, Eric R A N; Smith, Leeanna

2010-09-01

370

46 CFR 108.449 - Piping tests.  

Code of Federal Regulations, 2010 CFR

...SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.449 Piping tests. (a) Each test prescribed in (b), (c),...

2010-10-01

371

46 CFR 108.449 - Piping tests.  

Code of Federal Regulations, 2011 CFR

...SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.449 Piping tests. (a) Each test prescribed in (b), (c),...

2011-10-01

372

26th Annual offshore technology conference: 1994 Proceedings  

SciTech Connect

This conference represents the world's largest and most comprehensive technical conference and exhibition on offshore resource development. The four proceedings volumes have been separated by major areas of interest with this volume containing papers relative to design of offshore platforms and marine riser systems. Papers deal with design, installation, fabrication, transport systems, mooring devices, repair methods, and development of satellite production facilities. Case histories on various offshore oil and gas fills are discussed along with economics of some applications and designs.

Not Available

1994-01-01

373

Offshore Code Comparison Collaboration (OC3) for IEA Wind Task 23 Offshore Wind Technology and Deployment  

SciTech Connect

This final report for IEA Wind Task 23, Offshore Wind Energy Technology and Deployment, is made up of two separate reports, Subtask 1: Experience with Critical Deployment Issues and Subtask 2: Offshore Code Comparison Collaborative (OC3). Subtask 1 discusses ecological issues and regulation, electrical system integration, external conditions, and key conclusions for Subtask 1. Subtask 2 included here, is the larger of the two volumes and contains five chapters that cover background information and objectives of Subtask 2 and results from each of the four phases of the project.

Jonkman, J.; Musial, W.

2010-12-01

374

The tectono-stratigraphic evolution of basement highs in hyper extended deep-water rifted margins : the example of the Briançonnais domain in the Alps and comparisons with modern analogues  

NASA Astrophysics Data System (ADS)

The discovery of hydrocarbon systems in hyper-extended deep-water rifted margins, in conjunction with technical developments, expanded the hydrocarbon exploration into domains that are yet little investigated. The increasing number of high-quality reflection and refraction seismic surveys and drill hole data show that deep-water rifted margins are very different from proximal rifted margins. The new data show evidence for a polyphase rift evolution resulting in complex rift architectures with variable amounts of magmatic addition and local mantle exhumation that cannot be predicted by classical rift models. Thus, understanding the thermal structure, subsidence history, depositional environment and sedimentary architecture is a prerequisite to apply the "play elements" in these yet little investigated domains, which is essential to evaluate the survivability of syn- to post-rift petroleum systems. Although a big progress was made in the understanding of deep water rifted margins in the last 5 years, there are still many fundamental questions that remain open and ask for further research on this topic. One open scientific question is related to the tectono-sedimentary evolution and subsidence history of basement highs in deep water rifted margins. Péron-Pinvidic and Manatschal (2010) showed that different types of basement highs can be distinguished in rifted margins. These highs include micro-continents, continental ribbons, H-blocks and extensional allochthons. Mapping these highs and properly define their stratigraphic and tectonic evolution provide important insights into the tectonic evolution of rifted margins. However, these blocks are often at deep-water and sealed by thick post-rift sediments. Therefore access to direct observations requires expensive drillings. An alternative way to study these blocks is to use field analogues. One of which is the Briançonnais domain in the Alps. To achieve our goal we propose to review the existing structural, stratigraphic and age data from the whole Briançonnais domain (from Liguria/Italy, across the French Alps to Grisons in Switzerland). We propose to construct key tectonic sections across the Briançonnais domain. These data will form the basis to discuss the rift-related tectono-stratigraphic and subsidence evolution and to constrain the along and across strike stratigraphic architecture of the Briançonnais. These observations will be compared with that of seismically imaged basement highs in deep-water rifted margins (e.g. outer high in Campos or Santos). In our presentation we will show results of our preliminary works on the Briançonnais domain in the French Alps and a comparisons with seismically imaged basement highs imaged offshore Newfoundland.

Haupert, Isabelle; Manatschal, Gianreto; Unternehr, Patrick; Decarlis, Alessandro

2013-04-01

375

Operational Impacts of Large Deployments of Offshore Wind (Poster)  

SciTech Connect

The potential operational impact of deploying 54 GW of offshore wind in the United States was examined. The capacity was not evenly distributed; instead, it was concentrated in regions with better wind quality and close to load centers (Table 1). A statistical analysis of offshore wind power time series was used to assess the effect on the power system. The behavior of offshore wind resembled that of onshore wind, despite the former presenting higher capacity factors, more consistent power output across seasons, and higher variability levels. Thus, methods developed to manage onshore wind variability can be extended and applied to offshore wind.

Ibanez, E.; Heaney, M.

2014-10-01

376

Seismic modeling for gas field development in offshore Niger Delta: A case history  

SciTech Connect

In practice, seismic data has been used to map the geometry of events in the subsurface, mainly from reflection continuity and the character of reflection packages. Seismic modeling techniques are attempts to mathematically and geometrically represent the geology of the subsurface and to depict the interaction of the geology with a propagating seismic wave front. In the Niger delta, recent development in stratigraphic exploration has induced the examination of more subtle features of reflection, mainly polarity, amplitude, and waveform, to define the limits of seismic resolution and hence predict the geometry of the subsurface fluid and solid interfaces. The field being appraised for development in this study is located approximately 35 km offshore southeast of the Niger delta in a water depth ranging from 20 to 25 m, and the project involves a modeling evaluation of five sand units encountered at different levels in the subsurface. The sands being modeled occur within the Agbada Formation (Miocene age), an alternation sequence of transitional sands and shales characterized by high-amplitude, anomalous seismic events over the Nkop field. Structurally, the field is characterized by seaward facing, contemporaneous growth faults consisting mainly of a rollover anticline located in a regional fault couple, bounded to the north and south by a growth fault.

Idowu, A.O. (Nigerian National Petroleum Corp., Lagos (Nigeria))

1994-07-01

377

Sequence stratigraphy and hydrocarbon potential of the Phu Khanh Basin offshore central Vietnam, South China Sea  

SciTech Connect

The Phu Khanh Basin offshore central Vietnam is one of the few untested basins on the Vietnam margin of the South China Sea. Analysis of over 1,600 km of multi-channel seismic reflection data indicates that the Phu Khanh Basin follows a typical rift-margin order: faulted basement, synrift sedimentation, a breakup unconformity, and postrift sedimentation. Postrift sedimentation consists of a transgressive phase characterized by ramp-like depositional geometries followed by a regressive phase characterized by prograding sequences. An early middle Miocene unconformity separates these two phases. During the transgressive phase rising sea level provided favorable conditions for carbonate buildup development. The regressive interval contains a number of third-order depositional sequences composed of seismically resolvable lowstand, highstand, and rarely, transgressive systems tracts. Lacustrine sediments deposited in graben and half-graben lakes during the rifting stage are probably the principal source rocks. Fractured and/or weathered basement, carbonate complexes, basinfloor fans, and shallows water sands may have good reservoir quality. Potential traps include basement hills, carbonate complexes, fault taps, and stratigraphic traps within lowstand systems tracts. Hydrocarbon indicators such as flat spots, bright spots, gas chimneys with gas mounds on the seafloor occur at a number of locations.

Lee, G.H. (Kunsan National Univ. (Korea, Republic of)); Watkins, J.S. (Texas A M Univ., College Station, TX (United States))

1996-01-01

378

Sequence stratigraphy and hydrocarbon potential of the Phu Khanh Basin offshore central Vietnam, South China Sea  

SciTech Connect

The Phu Khanh Basin offshore central Vietnam is one of the few untested basins on the Vietnam margin of the South China Sea. Analysis of over 1,600 km of multi-channel seismic reflection data indicates that the Phu Khanh Basin follows a typical rift-margin order: faulted basement, synrift sedimentation, a breakup unconformity, and postrift sedimentation. Postrift sedimentation consists of a transgressive phase characterized by ramp-like depositional geometries followed by a regressive phase characterized by prograding sequences. An early middle Miocene unconformity separates these two phases. During the transgressive phase rising sea level provided favorable conditions for carbonate buildup development. The regressive interval contains a number of third-order depositional sequences composed of seismically resolvable lowstand, highstand, and rarely, transgressive systems tracts. Lacustrine sediments deposited in graben and half-graben lakes during the rifting stage are probably the principal source rocks. Fractured and/or weathered basement, carbonate complexes, basinfloor fans, and shallows water sands may have good reservoir quality. Potential traps include basement hills, carbonate complexes, fault taps, and stratigraphic traps within lowstand systems tracts. Hydrocarbon indicators such as flat spots, bright spots, gas chimneys with gas mounds on the seafloor occur at a number of locations.

Lee, G.H. [Kunsan National Univ. (Korea, Republic of); Watkins, J.S. [Texas A& M Univ., College Station, TX (United States)

1996-12-31

379

Petroleum geology of the Gulf of Lion (Mediterranean offshore-France)  

SciTech Connect

The onshore sedimentary basins of Camargue and the northern edge of the Gulf of Lion have been explored since the middle of the last century. The results of this petroleum exploration were poor despite two small oil discoveries: the Oligocene onshore Gallician field and the Triassic onshore Gabian field (respectively 7000 tons and 23000 tons of oil production). Eleven wells were drilled offshore (from 1968 to 1985), all located on highs of the pre-Tertiary substratum. Few oil and gas shows were proven by only three of these wells. The seismic data base has been fully reinterpreted. The mapping of the pre-Tertiary substratum shows wide unexplored grabens in the Gulf of Lion. Some Oligocene prospects have been evidenced which are either stratigraphic traps or faulted blocks associated to salt seals. A new set of geochemical analysis of the Oligocene source rock has been performed as well as systematic generation and migration models (1D and 2D models) leading to the definition of an effective oil kitchen of an Oligocene lacustrine source rock (type 1).

Vially, R.; Jean-Jacques, B.; Alain, I.E.M. [Ifp, Rueil Malmaison (France)

1995-08-01

380

Remote Stratigraphic Analysis: Combined TM and AIS Results in the Wind River/bighorn Basin Area, Wyoming  

NASA Technical Reports Server (NTRS)

An in-progress study demonstrates the utility of airborne imaging spectrometer (AIS) data for unraveling the stratigraphic evolution of a North American, western interior foreland basin. AIS data are used to determine the stratigraphic distribution of mineralogical facies that are diagnostic of specific depositional environments. After wavelength and amplitude calibration using natural ground targets with known spectral characteristics, AIS data identify calcite, dolomite, gypsum and montmorillonite-bearing strata in the Permian-Cretaceous sequence. Combined AIS and TM results illustrate the feasibility of spectral stratigraphy, remote analysis of stratigraphic sequences.

Lang, H. R.; Paylor, E. D.; Adams, S.

1985-01-01

381

77 FR 75187 - Notice of Determination of No Competitive Interest, Offshore Maine  

Federal Register 2010, 2011, 2012, 2013, 2014

...Determination of No Competitive Interest, Offshore Maine AGENCY: Bureau of Ocean Energy Management...Proposed Commercial Wind Lease Offshore Maine...Outer Continental Shelf (OCS) Offshore Maine, Request for Interest (RFI), that...

2012-12-19

382

75 FR 29397 - National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling  

Federal Register 2010, 2011, 2012, 2013, 2014

...Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling By the authority...Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling (the ``Commission...and mitigating the impact of, oil spills associated with offshore...

2010-05-26

383

33 CFR 100.728 - Special Local Regulations; Hurricane Offshore Classic, St. Petersburg, FL.  

Code of Federal Regulations, 2013 CFR

... false Special Local Regulations; Hurricane Offshore Classic, St. Petersburg...100.728 Special Local Regulations; Hurricane Offshore Classic, St. Petersburg...All vessel traffic, not involved in the Hurricane Offshore Classic, entering...

2013-07-01

384

33 CFR 100.728 - Special Local Regulations; Hurricane Offshore Classic, St. Petersburg, FL.  

Code of Federal Regulations, 2011 CFR

... false Special Local Regulations; Hurricane Offshore Classic, St. Petersburg...100.728 Special Local Regulations; Hurricane Offshore Classic, St. Petersburg...All vessel traffic, not involved in the Hurricane Offshore Classic, entering...

2011-07-01

385

33 CFR 100.728 - Special Local Regulations; Hurricane Offshore Classic, St. Petersburg, FL.  

Code of Federal Regulations, 2014 CFR

... false Special Local Regulations; Hurricane Offshore Classic, St. Petersburg...100.728 Special Local Regulations; Hurricane Offshore Classic, St. Petersburg...All vessel traffic, not involved in the Hurricane Offshore Classic, entering...

2014-07-01

386

33 CFR 100.728 - Special Local Regulations; Hurricane Offshore Classic, St. Petersburg, FL.  

Code of Federal Regulations, 2012 CFR

... false Special Local Regulations; Hurricane Offshore Classic, St. Petersburg...100.728 Special Local Regulations; Hurricane Offshore Classic, St. Petersburg...All vessel traffic, not involved in the Hurricane Offshore Classic, entering...

2012-07-01

387

Offshore wind farm siting procedures applied offshore of Block Island, Rhode Island  

NASA Astrophysics Data System (ADS)

Since 2008, the Rhode Island Coastal Resources Management Council (CRMC) has been leading a Rhode Island Ocean Area Management Plan (RIOSAMP) in partnership with the University of Rhode Island, resulting in an extensive multidisciplinary analysis of the Rhode Island offshore environment and its suitability for siting an offshore wind farm. As part of the RIOSAMP project, a standard siting optimization approach was first developed based on a siting index defined as the ratio of costs associated with the wind farm deployment to the available wind resource. This index, combined within a marine spatial planning approach to address ecological and societal constraints, provided an initial macro-siting tool (Spaulding et al., 2010). The multiple GIS layers required in this approach and the absence of theoretical support to optimize the resulting zoning, led to an extension of the initial optimization approach into a more comprehensive macro-siting optimization tool, integrating societal and ecological constraints into the siting tool, the Wind Farm Siting Index (WIFSI) (Grilli et al, 2012). The projects led to the definition of several favorable development areas including a Renewable Energy Zone (REZ) off of Block Island, in State Waters. Deep Water Wind Inc. (DWW) plans to install and commission five 6 MW direct drive Siemens lattice jacket turbines in the REZ area, by 2014. In this thesis two major steps are accomplished to refine and expand the RIOSAMP macro-siting tool. First the macro-siting tool is expanded to include a model simulating the exclusionary zones defined by the Federal Aviation Administration (FAA) regulations. Second a micro-siting model is developed, optimizing the relative position of each turbine within a wind farm area. The micro-siting objective is to minimize, (1) the loss in power due to the loss of wind resource in the wake of the turbines (wake "effect"), and (2) the cable costs that inter-connect the turbines and connecting the farm to the land. The REZ area is chosen as test site for the algorithm, and an optimal layout for the 5 turbines is found and discussed. Similarly the FAA tool is applied to the Block Island airport demonstrating the complexity of the FAA exclusionary area, and defining the limits of the exclusionary areas. The FAA regulation model is a geometric model in which all major (FAA) regulations within RI and the RI topography are embedded. The user specifies the dimension of the proposed turbines and an airport of interest, and a map of exclusionary zones specific to the turbine height and rules applying to the airport is generated. The model is validated for the entire state of Rhode Island. The micro-siting model finds the optimum placement of each turbine for a given number of turbines within an area. It includes the aerodynamic constraints (loss in wind speed within the wake of a turbine) associated to the deployment of arrays of turbines and the cable interconnection cost. It is combined with the technical, ecological, and social constraints used in the RIOSAMP macro-siting tool to provide a comprehensive micro-siting tool. In the optimization algorithm, a simple wake model and turbine-clustering algorithm are combined with the WIFSI in an objective function; the objective function is optimized with a genetic algorithm (GA).

O'Reilly, Christopher M.

388

About offshore resource assessment with floating lidars with special respect to turbulence and extreme events  

NASA Astrophysics Data System (ADS)

Offshore resource assessment with lidars on floating platforms is a flexible and particularly cost-effective alternative to the conventional meteorological mast solution, that is considered as onshore state-of-the-art transferred to offshore sites, and may enable better and more complete wind resource assessments for the growing offshore wind sector. Wind lidar technology, and remote sensing in general, has already been proven to be a very promising technology for resource assessment and power performance testing onshore. For offshore applications and on floating platforms in particular, the motions from the floating base have to be considered in addition, affecting the wind measurements significantly and causing systematic measurement errors. We have studied the motions and the corresponding influences on lidar measurements generated by different possible offshore platforms – vessels or buoys – both in detailed simulations as well as first validation experiments. In addition to this, we have developed motion compensation algorithms that allow to correct the affected measurements and retrieve the undisturbed wind data. The motions considered and studied comprise rotations as well as translations in all six degrees of freedom. For the evaluation of the motion-affected and corrected wind data in this paper, special attention is paid to the measurement of turbulence as well as extreme wind events. The research question to be answered is if a lidar device placed on a floating platform is capable of measuring more or less the same statistics of extreme wind events as a fixed lidar device. Quantities to be investigated are: the turbulence intensity as well as the statistics of maximum wind speed values within a 10-min period, but also wind speed increments on different time scales. At this, obviously two issues are to be discussed – the influence of the lidar measurement principle on the recording of extreme wind events, and the additional impact of the superimposed motions of the floating platform.

Gottschall, J.; Wolken-Möhlmann, G.; Lange, B.

2014-12-01

389

Seismic stratigraphic study of two Oxfordian carbonate sequences, eastern Saudi Arabia  

SciTech Connect

In this case study, seismic stratigraphic interpretation techniques were used to map facies changes and develop a depositional model for two Oxfordian carbonate sequences of eastern Saudi Arabia. Well data and regional geology indicate that the two sequences, R1 and R2, were deposited on a broad carbonate platform and undergo a lateral transition from grainstone to basinal mudstone within the study area. A seismic grid tied to well control was used to map facies transitions. Vertical resolution was a major factor in selecting acceptable lines from existing coverage. A high-resolution line, which tied wells on either side of the R1 and R2 transitions, was recorded and processed for stratigraphic objectives. Special seismic displays and ray trace modeling were applied at interpretive aids for this key line. The seismic interpretation procedure consisted of three steps: seismic sequence identification, seismic facies analysis, and Jurassic sea level correlation. 13 figures.

Langdon, G.S.; Malecek, S.J.

1987-04-01

390

Using 3D visualization and seismic attributes to improve structural and stratigraphic resolution of reservoirs  

SciTech Connect

Recent advances in hardware and software have given the interpreter and engineer new ways to view 3D seismic data and well bore information. Recent papers have also highlighted the use of various statistics and seismic attributes. By combining new 3D rendering technologies with recent trends in seismic analysis, the interpreter can improve the structural and stratigraphic resolution of hydrocarbon reservoirs. This paper gives several examples using 3D visualization to better define both the structural and stratigraphic aspects of several different structural types from around the world. Statistics, 3D visualization techniques and rapid animation are used to show complex faulting and detailed channel systems. These systems would be difficult to map using either 2D or 3D data with conventional interpretation techniques.

Kerr, J. [Landmark Graphics Corp., Weybridge (United Kingdom); Jones, G.L. [Landmark Graphics Corp., Houston, TX (United States)

1996-12-31

391

Using 3D visualization and seismic attributes to improve structural and stratigraphic resolution of reservoirs  

SciTech Connect

Recent advances in hardware and software have given the interpreter and engineer new ways to view 3D seismic data and well bore information. Recent papers have also highlighted the use of various statistics and seismic attributes. By combining new 3D rendering technologies with recent trends in seismic analysis, the interpreter can improve the structural and stratigraphic resolution of hydrocarbon reservoirs. This paper gives several examples using 3D visualization to better define both the structural and stratigraphic aspects of several different structural types from around the world. Statistics, 3D visualization techniques and rapid animation are used to show complex faulting and detailed channel systems. These systems would be difficult to map using either 2D or 3D data with conventional interpretation techniques.

Kerr, J. (Landmark Graphics Corp., Weybridge (United Kingdom)); Jones, G.L. (Landmark Graphics Corp., Houston, TX (United States))

1996-01-01

392

Youngest Toba Tuff in the Son Valley, India: a weak and discontinuous stratigraphic marker  

NASA Astrophysics Data System (ADS)

Investigation of the climatic and environmental impacts of the Youngest Toba Tuff (YTT, ˜74 ka BP) eruption of Toba volcano, Sumatra, is crucial for understanding the consequences of the eruption for contemporaneous human populations. The Middle Son Valley, in India, was the first locality on the Indian subcontinent where the YTT was reported. The ash bed forms a discontinuous layer stretching for over 30 km along the river. Here we report on the stratigraphic contexts of YTT ash layers in alluvial deposits of the Middle Son Valley, in order to reconstruct the taphonomy of the ash deposits and the dynamic of their deposition. Although the distal ash has been studied since the 1980s, its stratigraphic integrity and the mechanisms and pathways involved in its transport and deposition have bit previously been assessed. We find that the YTT occurrences in the Middle Son Valley may not be reliable chronostratigraphical markers for millennial scale palaeoenvironmental reconstruction.

Gatti, E.; Durant, A. J.; Gibbard, P. L.; Oppenheimer, C.

2011-12-01

393

Sequence stratigraphy of the Orange basin, western offshore South Africa  

Microsoft Academic Search

A seismic\\/sequence-stratigraphic framework for the siliciclastic fluvial to deepwater Cretaceous strata of the Orange basin has been constructed. Sequence-stratigraphic concepts developed by Exxon were used to interpret 10,000 km of seismic data and logs from 31 exploration boreholes within an area of 90,000 km². The sequence stratigraphy of the western margin exhibits 34 cyclical depositional sequences interpreted to document the

1991-01-01

394

Lower Vendian microfossil assemblages of East Siberia: Significance for solving regional stratigraphic problems  

NASA Astrophysics Data System (ADS)

Both published and original data are used for the analysis of the stratigraphic position and taxonomic characteristics for acanthomorphic microfossils of the Pertatataka type in Lower Vendian sediments of the central and southeastern Siberian Platform and its surrounding structures. Four taxonomically different microbiotas are distinguished in sections of the Nepa-Botuoba, Fore-Patom; Syugdzher, Anabar, Zhuya-Lena, and Berezovo lithotectonic zones: two diverse (Nepa and Ura) and two impoverished (Otradnino and Torga) each including diagnostic Early Vendian taxa. Beyond the Siberian Platform, genera and species characterizing these microbiotas occur in single assemblages and represent diagnostic taxa of the second (Tc-Sr-Vl) and third (Ti-Cg-Mp) zones of the acritarch scale proposed by Australian geologists as a biostratigraphic basis for subdividing the Ediacarian of the Standard stratigraphic scale (SSS). In the Russian General stratigraphic scale, the distribution of Pertatataka acritarchs corresponds to the Lower Vendian. The appearance and mass development of acanthomorphic microorganisms represents a global biological event, which should be taken into consideration as a biostratigraphic criterion for defining the Vendian System. For substantiating age, the following species among diagnostic Lower Vendian forms of East Siberia should be used: Appendisphaera grandis, “Appendisphaera” tabifica, A. tenuis, Ceratosphaeridium glaberosum, Dicrospinosphaera virgata, Multifronsphaeridium pelorium, “Polygonium” cratum, Tanarium conoideum, Variomargosphaeridium litoschum, and Talakania obscura. These taxa are readily recognizable, morphologically stable, and characterized by their wide lateral distribution and relatively narrow stratigraphic range. Their occurrence in the upper part of the Dal’nyaya Taiga Group of the Baikal-Patom region indicates that host sediments should be attributed to the Lower Vendian, not the Upper Riphean as is currently accepted.

Golubkova, E. Yu.; Raevskaya, E. G.; Kuznetsov, A. B.

2010-08-01

395

Three-dimensional seismic stratigraphic study of Minnelusa Formation, Powder River basin, Campbell County, Wyoming  

E-print Network

Chug- water Group row Mounuun Spearfish Formation PERMIAN Goose Egg Fm missing Opcchc Shale PENNSYLVANIAN MISSISSIPPIAN Minnelusa Formauon Arrmlcn Formation missing Madison Limestune FIG. 2. Stratigraphic column of the Powder River basin... than 20, 000 ft/sec) shaded darkly in the models, medium velocities (between 15, 000 and 20, 000 ft/sec) shaded lightly in the models, and low velocities (less than 15, 000 55 11200'? Goose Egg 17241 FT/SEC 11300'? 20833 16667 Minnekahta...

Walters, Donna Lynn

1988-01-01

396

Structural and stratigraphic evolution of Shira Mountains, central Ucayali Basin, Peru?  

E-print Network

sandstones and can be identified in all the wells in the Ucayali Basin (Quintana Minerals, 1998). The Tertiary section forms of a wedge-shaped foredeep deposit of red bed cycles with poor hydrocarbon potential interbedded with the Pozo Shale and Sand... STRUCTURAL AND STRATIGRAPHIC EVOLUTION OF SHIRA MOUNTAINS, CENTRAL UCAYALI BASIN, PERÚ A Thesis by JAIME ORLANDO SANCHEZ ALVAREZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

Sanchez Alvarez, Jaime Orlando

2008-10-10

397

Computer program for stratigraphic correlation of Devonian shales in Appalachian basin  

SciTech Connect

A computer program has been written to perform graphic and computational functions related to stratigraphic correlation. Stratigraphic information is retrieved from a data base and used to interpolate formation tops between wells. A stratigraphic cross section can then be drawn on a graphics terminal. Kriging is employed in the interpolation to control smoothing. The user can stipulate which wells are included in the cross section, or ask for wells near a specific location or near a specific well. The cross section and other output from the program can be used to determine pay zones that were not correctly interpreted by a driller, to confirm a stratigrapher's correlations, and to find anomalous information in the data base. Estimated tops can be stored in the data base from within the program. Additional graphic activities include drawing a map of well locations and a graphic comparison of a strip log drawn from user-entered driller's lithologic tops and the interpolated tops. The driller's tops and interpolated tops can be matched by the program. The user can choose to turn off the graphics and just interpolate tops for each well on a list provided by the user. If some tops are known in a well, these can be used to interpolate the remaining tops. The base of the Berea Sandstone is commonly used. Accuracy of the interpolations increases as more known tops are used. The program is written in FORTRAN, and uses PLOT 10 Graphical Kernal System. It runs on a VAX 11/750. A Tektronix 4207 color terminal is needed unless the user opts for no graphics.

Timberlake, K.; Hohn, M.; Kite, S.; Behling, M.C.

1988-08-01

398

Geomorphic and stratigraphic analysis of Crater Terby and layered deposits north of Hellas basin, Mars  

Microsoft Academic Search

The geologic history of Crater Terby is developed through geomorphic and stratigraphic analyses within the regional context of the Hellas basin. Terby exhibits ?2-km-thick sequences of layers that consist of repetitive, subhorizontal and laterally continuous beds. The layers are predominantly fine-grained as indicated by their ease of aeolian erosion, although a few consolidated layers weather to form rubbly talus. The

Sharon A. Wilson; Alan D. Howard; Jeffrey M. Moore; John A. Grant

2007-01-01

399

Proceedings of the 25th annual offshore technology conference. Volume 1: Geology, earth sciences and environment  

SciTech Connect

This conference proceedings represents volume 1 of a 4 volume conference relating to offshore operations in both energy and non-energy fields of resource development. This volume discusses the use of geophysical surveying techniques and equipment for mapping the seafloor; the design and use of offshore platforms; safety engineering systems; interpretation techniques for offshore survey data; environmental impacts from offshore operations; geology of offshore areas; and regulations pertaining to the development of offshore resources.

Not Available

1993-01-01

400

Homopolar pulse welding for offshore deep water pipelines  

SciTech Connect

Homopolar pulse welding (HPW) is a one-shot resistance welding process being investigated as a method to join API 5L carbon steel line pipe. Homopolar pulse welding utilizes the high current, low voltage electrical pulse produced by a homopolar generator to rapidly resistance heat the interface between abutting pipe ends, producing a full circumference resistance forge weld requiting no filler metal in under three seconds. A five year joint industry program is sponsoring HPW research with the goal of developing the process for deep water offshore pipeline construction utilizing the J-lay method The first two years of the program have concentrated on weld parameter optimization by producing, testing, and evaluating welds in various grades, wall thicknesses, types and compositions of 3 inch nominal (3.5 inch OD) diameter API 5L carbon steel pipe. Mechanical properties of the welds and parent metal were evaluated by tensile testing, impact testing, and hardness traverse testing according to guidelines and criteria established by the industrial sponsors. Homopolar pulse welding has demonstrated the capability to produce industrially acceptable full circumference welds in carbon steel line pipe via a rapid, one-shot process. Future work will concentrate on developing the process for commercial field installation, with the program`s goal being the demonstration of a prototype system for producing HPW welds in 12 inch diameter pipe in a J-lay configuration.

Haase, P.W.; Carnes, R.W.; Hudson, R.S. [Univ. of Texas, Austin, TX (United States). Center for Electromechanics

1995-12-31

401

Sequence stratigraphic and sedimentologic significance of biogenic structures from a late Paleozoic marginal- to open-marine reservoir, Morrow Sandstone, subsurface of southwest Kansas, USA  

USGS Publications Warehouse

Integrated ichnologic, sedimentologic, and stratigraphic studies of cores and well logs from Lower Pennsylvanian oil and gas reservoirs (lower Morrow Sandstone, southwest Kansas) allow distinction between fluvio-estuarine and open marine deposits in the Gentzler and Arroyo fields. The fluvio-estuarine facies assemblage is composed of both interfluve and valley-fill deposits, encompassing a variety of depositional environments such as fluvial channel, interfluve paleosol, bay head delta, estuary bay, restricted tidal flat, intertidal channel, and estuary mouth. Deposition in a brackish-water estuarine valley is supported by the presence of a low diversity, opportunistic, impoverished marine ichnofaunal assemblage dominated by infaunal structures, representing an example of a mixed, depauperate Cruziana and Skolithos ichnofacies. Overall distribution of ichnofossils along the estuarine valley was mainly controlled by the salinity gradient, with other parameters, such as oxygenation, substrate and energy, acting at a more local scale. The lower Morrow estuarine system displays the classical tripartite division of wave-dominated estuaries (i.e. seaward-marine sand plug, fine-grained central bay, and sandy landward zone), but tidal action is also recorded. The estuarine valley displays a northwest-southeast trend, draining to the open sea in the southeast. Recognition of valley-fill sandstones in the lower Morrow has implications for reservoir characterization. While the open marine model predicts a "layer-cake" style of facies distribution as a consequence of strandline shoreline progradation, identification of valley-fill sequences points to more compartmentalized reservoirs, due to the heterogeneity created by valley incision and subsequent infill. The open-marine facies assemblage comprises upper, middle, and lower shoreface; offshore transition; offshore; and shelf deposits. In contrast to the estuarine assemblage, open marine ichnofaunas are characterized by a high diversity of biogenic structures representing the activity of a benthic fauna developed under normal salinity conditions. Trace fossil and facies analyses allow environmental subdivision of the shoreface-offshore successions and suggest deposition in a weakly storm-affected nearshore area. An onshore-offshore replacement of the Skolithos ichnofacies by the Cruziana ichnofacies is clearly displayed. The lower Morrow fluvio-estuarine valley was incised during a drop of sea level coincident with the Mississippian-Pennsylvanian transition, but was mostly filled during a subsequent transgression. The transgressive nature of the estuarine infill is further indicated by the upward replacement of depauperate brackish-water trace fossil assemblages by the open-marine Cruziana ichnofacies. Additional stratal surfaces of allostratigraphic significance identified within the estuary include the bayline surface, the tidal ravinement surface, the wave ravinement surface, and a basinwide flooding surface recording inundation of the valley interfluves. A younger sequence boundary within the lower Morrow is also recorded in the Gentzler field at the base of a forced regression shoreface, demarcated by the firmground Glossifungites ichnofacies, indicating a rapid basinward facies migration during a sea-level drop. Trace fossil models derived from the analysis of Mesozoic and Cenozoic reservoirs are generally applicable to the study of these late Paleozoic reservoirs. Pennsylvanian brackish-water facies differ ichnologically from their post-Paleozoic counterparts, however, in that they have: (1) lower trace fossil diversity, (2) lower degree of bioturbation, (3) scarcity of crustacean burrows, (4) absence of firmground suites, and (5) absence of ichnotaxa displaying specific architectures designed to protect the tracemaker from salinity fluctuations. Morrow open-marine ichnofaunas closely resemble their post-Paleozoic equivalents. ?? 2002 Elsevier Science B.V. All rights reserved.

Buatois, L.A.; Mangano, M.G.; Alissa, A.; Carr, T.R.

2002-01-01

402

BIO-OFFSHORE: Grootschalige teelt van zeewieren in combinatie met offshore windparken in de Noordzee  

Microsoft Academic Search

This study addresses the technological feasibility of seaweed cultivation in the North Sea in combination with offshore wind parks and harvesting and conversion of seaweed biomass to renewable energy carriers and chemicals. The study also identifies stakeholders and participants for technology development and the ecological and societal conditions to fit in large-scale seaweed cultivation in the marine environment, existing marine

E. H. Reith; E. P. Deurwaarder; K. Hemmes; A. P. W. M. Curvers; P. Kamermans; W. A. Brandenburg; G. Lettings

2005-01-01

403

About Hercules Offshore Headquartered in Houston, Texas, Hercules Offshore serves the oil and  

E-print Network

provides shallow-water drilling and support services to the oil and gas industry. The company serves national oil and gas companies, major integrated energy companies and natural gas operators. Shallow-water, Hercules Offshore was faced with a need to upgrade. The company had customized the original Oracle

Fisher, Kathleen

404

Examination of spaceborne imaging spectroscopy data utility for stratigraphic and lithologic mapping  

NASA Astrophysics Data System (ADS)

Due to the increasing development of image spectroscopy techniques, airborne and spaceborne hyperspectral images have in recent years become readily available for use in geological applications. One of the prominent advantages of imaging spectroscopy is its high spectral resolution, producing detailed spectral information in each pixel. The current study aims at exploring the feasibility of the Earth-Observing-1 Hyperion imaging spectrometer to map the geology arena over the Dana Geology National Park, Jordan. After overcoming the common preprocessing difficulties (e.g., smile effect), a classification scheme of two levels was applied. The first level resulted in a stratigraphic classification product of eleven classes and the second level in a lithologic classification product of six classes. The overall accuracy of the stratigraphic product was 57%, while that of the lithologic product was 79%. Mismatches in classification were mostly related to terrestrial cover of the lower topography formation by rock and sand debris. In addition, low accuracy values can be attributed to Hyperion's high sensitivity, leading to recognition of different mineral compositions as different classes within a rock formation, while the conventional geology-stratigraphic map generalizes these different classes into one formation. The methods practiced in the current research can advance the Hyperion's classification capabilities and therefore can be applied in different geological settings and additional disciplines such as penology, agriculture, ecology, forestry, urban, and other environmental studies.

Dadon, Alon; Ben-Dor, Eyal; Beyth, Michael; Karnieli, Arnon

2011-01-01

405

Modeling of stratigraphic columns using Markov Chains and Gibbs sampling algorithms, Campo Oritupano, Venezuela.  

NASA Astrophysics Data System (ADS)

The interbeded sandstones, siltstones and shale layers within the stratigraphic units of the Oficina Formation were stochastically characterized. The units within the Oritupano field are modeled using the information from 12 wells and a post-stack 3-D seismic cube. The Markov Chain algorithm was successful at maintaining the proportion of lithotypes of the columns in the study area. Different transition probability matrixes are evaluated by changing the length of the sequences represented in the transition matrix and how this choice of length affects ciclicity and the genetic relations between lithotypes. The Gibbs algorithm, using small sequences as building blocks for modeling, kept the main stratigraphic succession according to the geology. Although the modeled stratigraphy depends strongly on initial conditions, the use of longer sequences in the substitution helps not to overweight the transition counts from one lithotype to the same in the main diagonal of the probability matrix of the Markov Chain in the Gibbs algorithm. A methodology based on the phase spectrum of the seismic trace for tying the modeled sequences with the seismic data is evaluated and discussed. The results point to the phase spectrum as an alternate way to cross-correlate synthetic seismograms with the seismic trace in favor of the well known amplitude correlation. Finally, a map of net sand over the study area is generated from the modeled columns and compared with previous stratigraphic and facies analysis at the levels of interest.

Durán, E.

2012-04-01

406

Effects of stratigraphic heterogeneity on permeability in eolian sandstone sequence, Page sandstone, northern Arizona  

SciTech Connect

Outcrop and core data from the eolian Middle Jurassic Page Sandstone of northern Arizona show that realistic reservoir characterization can be based on the stratigraphic architecture. Outcrop displays of differential weathering, coloration, cementation, and seepage reflect stratigraphic control of fluid flow within the sandstone. Measurements of permeability using a field permeameter and conventional analysis yield a five-order-of-magnitude range of values between distinct populations. Extra-erg and/or interdune deposits are least permeable (0.67-1800 md), followed by wind-ripple strata (900-5200 md), with grain-flow strata being the most permeable (3700-12,000 md). Extra-erg and interdune deposits and some extensive bounding surfaces form significant flow barriers and tend to compartmentalize the reservoir. Reservoir characteristics of the dune cross-strata are a function of the types, distributions, and orientations of the internal stratification. Directional-flow properties within the strata are most pronounced within wind-ripple laminae. Recognition of the levels of reservoir heterogeneity is sampling-scale dependent. General models for flow within single sets of cross-strata as well as within eolian sequences can be generated based upon relative permeability between stratigraphic units. 9 figures.

Chandler, M.A.; Kocurek, G.; Goggin, D.J.; Lake, L.W.

1989-05-01

407

Arctic and offshore research. Technology status report  

SciTech Connect

The DOE Arctic and Offshore Research (AOR) effort is designed to meet the needs for a centralized, high-quality, Arctic energy-related data base and for long-term, high-risk research. The ultimate purpose of the DOE effort is to promote extensive private use of the evolving AOR technology data base in order to accelerate development of Arctic oil and gas resources. In assessing the Arctic energy-related research needs as delineated in this report, the Morgantown Energy Technology Center (METC), with the DOE Fossil Energy Office of Oil, Gas, and Shale Technology, developed the following activities: AOR Energy-Related Technology Data Base Development; AOR Seminars and Workshops; Arctic and Offshore Energy Research Coordination; Sea Ice Research; Seafloor/Soils Research; and Subice Systems Development. The DOE AOR effort was initiated in FY 1983, the early development activities were performed in January and February 1983, and the effort evolved to its present form by the conclusion of FY 1984. The current activities have included determining the Arctic bibliographic data base and initiating most pieces of the research described above (except multiyear ice properties and pipeline research). Some of the FY 1984 major accomplishments are: four to five ice islands 1 to 2 miles in length drifting off the Ellesmere ice shelves north of Ellesmere Island were aerially surveyed. A report was completed on the location of the ice shelf edge, breakup, and regrowth of the Ellesmere ice shelves over the past two decades. Ice-ridging shear zone studies have shown that the 6- to 10-feet high shoals usually under the shear zone are not totally destroyed from ice gouging from one year to the next, but that the ice gouging may be instrumental in initiating and maintaining the shoals, which may protect Arctic offshore structures. Airborne radar sensing techniques were used to determine the electromagnetic properties of sea ice and physical properties.

Not Available

1984-10-01

408

Cathodic protection retrofit of an offshore pipeline  

SciTech Connect

Cathodic protection (CP) anodes and corrosion coating on two offshore pipelines were damaged during deep water installation. In-situ methods for deep-water inspection and repair of the pipelines` CP and coating systems were developed and used. High-pressure natural gas Pipeline. A design was 5.6 miles of 8.625 in. OD by 0.406 in. W.T. API SL, Grade X-42, seamless line pipe. Pipeline B design was 0.3 miles of similar specification pipe. Both pipelines were mill-coated with 14 mil of fusion-bonded epoxy (FBE) corrosion coating. Girth welds were field-coated with FBE.

Winters, R.H.; Holk, A.C. [Tenneco Energy, Houston, TX (United States)

1997-09-01

409

Unified design equation for offshore cathodic protection  

SciTech Connect

A new approach (the Unified Design Equation) is proposed for the design of sacrificial anode cathodic protection systems for offshore structures. This method results in a single design equation which incorporates both long term maintenance current density requirements and the use of high initial current density to achieve rapid polarization. The Unified Design Equation is compared to current design practice, to suggest values for the parameters useful for areas and conditions where historical designs are known to perform well. Under conditions where experience is lacking (e.g., new geographic areas, deep water, etc.) the design parameters can be determined experimentally.

Townley, D.W. [Chevron Petroleum Technology Co., La Habra, CA (United States)

1997-09-01

410

Variation in abundance of blacklip pearl oyster ( Pinctada margaritifera Linne.) spat from inshore and offshore reefs in Solomon Islands  

Microsoft Academic Search

This study was designed to test two predictions. The first was that collections of spat of the blacklip pearl oyster, Pinctada margaritifera, should be greater from offshore than inshore zones in ‘open’ reef systems adjacent to high islands. The second was that the lack of heavy run-off from land-masses will result in greater abundance of spat being caught from inshore

Kim J. Friedman; Johann D. Bell

1999-01-01

411

COMPARATIVE TOXICITY OF OFFSHORE AND OIL-ADDED DRILLING MUDS TO LARVAE OF THE GRASS SHRIMP 'PALAEMONETES INTERMEDIUS'  

EPA Science Inventory

Offshore drilling fluids (muds) varied widely in their toxicity to grass shrimp (Palaemonetes intermedius) larvae. The 96-hr LC50S for the eleven drilling muds tested ranged from 142 to >100,000 ppm (microliters/L). There was a significant correlation between oil content of the d...

412

Lithologo-facial, geochemical and sequence-stratigraphic sedimentation in Naunak suite (south-east Western Siberia)  

NASA Astrophysics Data System (ADS)

The paper describes lithofacial, geochemical, sequence-stratigraphical research results of facial environment reconstruction and oil and evaluation gas - bearing capacity potential for Naunak suite in south-east Western Siberia.

Shaminova, M.; Rychkova, I.; Sterzhanova, U.; Dolgaya, T.

2014-08-01

413

Technology assessment of offshore industry and its impact on the maritime industry 1976-2000. Executive summary. Final report  

Microsoft Academic Search

This report contains a 25 year forecast of the offshore industry including offshore petroleum production, offshore power production, offshore mining, offshore service platforms, and commercial ocean fishing. Each segment of the offshore industry is described in terms of the current status of industry, trends that might influence the direction of future development, and forces acting on the industry to impede

Durfee

1977-01-01

414

Glaciotectonic deformation and reinterpretation of the Worth Point stratigraphic sequence: Banks Island, NT, Canada  

NASA Astrophysics Data System (ADS)

Hill-hole pairs, comprising an ice-pushed hill and associated source depression, cluster in a belt along the west coast of Banks Island, NT. Ongoing coastal erosion at Worth Point, southwest Banks Island, has exposed a section (6 km long and ˜30 m high) through an ice-pushed hill that was transported ˜ 2 km from a corresponding source depression to the southeast. The exposed stratigraphic sequence is polydeformed and comprises folded and faulted rafts of Early Cretaceous and Late Tertiary bedrock, a prominent organic raft, Quaternary glacial sediments, and buried glacial ice. Three distinct structural domains can be identified within the stratigraphic sequence that represent proximal to distal deformation in an ice-marginal setting. Complex thrust sequences, interfering fold-sets, brecciated bedrock and widespread shear structures superimposed on this ice-marginally deformed sequence record subsequent deformation in a subglacial shear zone. Analysis of cross-cutting relationships within the stratigraphic sequence combined with OSL dating indicate that the Worth Point hill-hole pair was deformed during two separate glaciotectonic events. Firstly, ice sheet advance constructed the hill-hole pair and glaciotectonized the strata ice-marginally, producing a proximal to distal deformation sequence. A glacioisostatically forced marine transgression resulted in extensive reworking of the strata and the deposition of a glaciomarine diamict. A readvance during this initial stage redeformed the strata in a subglacial shear zone, overprinting complex deformation structures and depositing a glaciotectonite ˜20 m thick. Outwash channels that incise the subglacially deformed strata record a deglacial marine regression, whereas aggradation of glaciofluvial sand and gravel infilling the channels record a subsequent marine transgression. Secondly, a later, largely non-erosive ice margin overrode Worth Point, deforming only the most surficial units in the section and depositing a capping till. The investigation of the Worth Point stratigraphic sequence provides the first detailed description of the internal architecture of a polydeformed hill-hole pair, and as such provides an insight into the formation and evolution of an enigmatic landform. Notably, the stratigraphic sequence documents ice-marginal and subglacial glaciotectonics in permafrost terrain, as well as regional glacial and relative sea level histories. The reinterpreted stratigraphy fundamentally rejects the long-established paleoenvironmental history of Worth Point that assumed a simple ‘layer-cake’ stratigraphy including the type-site for an organically rich, preglacial interval (Worth Point Fm).

Vaughan, Jessica M.; England, John H.; Evans, David J. A.

2014-05-01

415

Service Offshoring and Productivity: Evidence from the United States  

Microsoft Academic Search

The practice of sourcing service inputs from overseas suppliers has been growing in response to new technologies that have made it possible to trade in some business and computing services that were previously considered non-tradable. This paper estimates the effects of offshoring on productivity in US manufacturing industries between 1992 and 2000. It finds that service offshoring has a significant

Mary Amiti; Shang-Jin Wei

2006-01-01

416

Quality risk in offshore manufacturing: Evidence from the pharmaceutical industry  

Microsoft Academic Search

Does offshore production pose an added quality risk relative to domestic production? If so, what factors influence the quality risk? Progress addressing these deceptively simple questions has been hindered by the challenges associated with (1) difficulties in controlling for a wide range of factors that may potentially affect quality risk in offshore manufacturing and (2) the lack of available measures

John V. Gray; Aleda V. Roth; Michael J. Leiblein

2011-01-01

417

Map of Offshore Wind Energy Activity in North America  

NSDL National Science Digital Library

This map, from the North American Offshore Wind Project shows a Google map of all locations considered for having offshore wind energy. The location markers also provide information as to which projects are operational, proposed, suspended, or that have notable activity.

North American Offshore Wind Project

418

International Collaboration on Offshore Wind Energy Under IEA Annex XXIII  

SciTech Connect

This paper defines the purpose of IEA Annex XXIII, the International Collaboration on Offshore Wind Energy. This international collaboration through the International Energy Agency (IEA) is an efficient forum from which to advance the technical and environmental experiences collected from existing offshore wind energy projects, as well as the research necessary to advance future technology for deep-water wind energy technology.

Musial, W.; Butterfield, S.; Lemming, J.

2005-11-01

419

REVIEW Open Access Assessing environmental impacts of offshore wind  

E-print Network

targets and environmental legislation. Keywords: Marine mammals, Seabirds, Wind turbine, Underwater noise offshore wind farm, Horns Rev 1 (160 MW with 80 turbines of 2 MW), became operational in 2002. The aver- age capacity of turbines and size of offshore wind farms have been increasing since then

Aberdeen, University of

420

In Brief: Environmental standards needed for offshore marine aquaculture  

Microsoft Academic Search

The U.S. Congress should enact legislation that sets strong environmental standards for offshore marine aquaculture, the Marine Aquaculture Task Force recommended in a recent report. Aquaculture now accounts for about half of all seafood consumed in the world, and the industry is rapidly growing and expanding into regions offshore (more than 3 nautical miles from the coast) that are controlled

Sarah Zielinski

2007-01-01

421

OPTIMAL DEVELOPMENT PLANNING OF OFFSHORE OIL AND GAS FIELD  

E-print Network

OPTIMAL DEVELOPMENT PLANNING OF OFFSHORE OIL AND GAS FIELD INFRASTRUCTURE UNDER COMPLEX FISCAL Pittsburgh, PA 15213 Abstract The optimal development planning of offshore oil and gas fields has received, well drilling schedule and production profiles of oil, water and gas in each time period. The model can

Grossmann, Ignacio E.

422

26th Annual offshore technology conference: 1994 Proceedings  

SciTech Connect

This conference is the world's largest and most comprehensive technical conference and exhibition on offshore resource development. This conference is divided into four volumes with this volume containing conference papers relative to offshore drilling and well completion information. Papers also deal with construction specifications for marine risers and pipelines, along with any relevant installation and