Science.gov

Sample records for khan basin offshore

  1. Offshore Essaouira basin: Geology and hydrocarbon potential

    SciTech Connect

    Jabour, H.; Ait Salem, A. )

    1991-03-01

    The study area lies in the offshore extension of the onshore Essaouria basin. The Mesozoic development of the Essaouira margin was largely controlled by Late Triassic to Mid-Jurassic rifting and subsequent opening of the Central Atlantic, with the evolution of a typical passive, opening of the Central Atlantic, with the evolution of a typical passive, continental margin. Diapiric salt structure recognized on seismic defines a Late Triassic-Early Jurassic salt basin in the offshore area initiated during early rifting. Subsidence and sea-level rise during Jurassic resulted in carbonate platform development. This was followed during Cretaceous and Tertiary time by the deposition of a prograding siliciclastic system. Only three wells have been drilled in this basin. Although drilled on poorly defined prospects, these wells encountered gas and oil shows. Fairly extensive seismic coverage of good quality data is now available. A study based on an integrated approach involving seismic facies definition and mapping, correlation with well data, identification of the principal control on sedimentation, and basin modeling in conjunction with source rock prediction and maturity modeling has been carried out. Results have shown that hydrocarbon potential in the offshore Essaouira basin has not yet been substantiated by drilling. Attractive structural and stratigraphic prospects exist in the shelf, shelf edge, and the slope, and await confirmation by drilling.

  2. Basin development and petroleum potential of offshore Otway basin, Australia

    SciTech Connect

    Williamson, P.E.; O'Brien, G.W.; Swift, M.G.; Scherl, A.S.; Marlow, M.S.; Exon, N.F.; Falvey, D.A.; Lock, J.; Lockwood, K.

    1987-05-01

    The Bass Strait region in southeastern Australia contains three sedimentary basins, which are, from east to west, the Gippsland, Bass, and Otway basins. The offshore Gippsland basin is Australia's most prolific petroleum-producing province and supplies over 90% of the country's production. In contrast, exploration has been unsuccessful in the offshore portion of the Otway basin; 17 wells have been drilled, and although shows of oil and gas have been common, no commercial discoveries have been made. Many of these wells, drilled in the 1960s and 1970s, were sited using poor-quality seismic data and, as a consequence, were frequently off structure. Seismic data quality has, however, improved significantly in recent years. The present study by the Australian Bureau of Mineral Resources (BMR) involved the collection, in the offshore Otway basin, of 3700 km of high-quality, 48-channel seismic reflection data by the BMR research vessel R/V Rig Seismic. These data have been integrated with existing industry seismic data, well data, limited dredged material, and geohistory analyses in a framework study of basin development and hydrocarbon potential in this under-explored area. The offshore Otway basin extends 500 km along the southern coastline and is typically 50 km wide in water depths of less than 200 m. It contains up to 10 km of predominantly late Mesozoic to early Cenozoic sediments, which are overlain by a thin sequence of middle to late Tertiary shelf carbonates. It has been divided into three main structural elements: the Mussel Platform in the east, the central Voluta Trough, and the Crayfish Platform in the west. The basin was initiated at the end of the Jurassic as part of the Bassian rift. Up to 6 km of Lower Cretaceous sediments were deposited prior to breakup at the end of the Early Cretaceous and the onset of sea-floor spreading between Australia and Antarctica.

  3. Geology of the Douala basin, offshore Cameroon, West Africa

    SciTech Connect

    Pauken, R.J.; Thompson, J.M.; Schumann, J.R. ); Cooke, J.C. )

    1991-03-01

    The Douala basin is predominantly an offshore basin extending from the Cameroon volcanic line in the north to the Corisco arch in the south near the Equatorial Guinea-Gabon border. The basin lies wholly within the territorial borders of Cameroon and Equatorial Guinea. The Douala basin is one of a series of divergent margin basins occurring along the southwest African coastline resulting from the rifting of Africa from South America. Continental rifting in the Doula basin was initiated at least by Aptian-Albian time and possibly as early as Jurassic. The rift stage persisted until Albian time when the onset of drifting occurred. The sedimentary section in the basin has a maximum thickness of 8-10 km, based on exploration drilling and gravity and magnetics modeling. The synrift section consists of Aptian-Albian sands and shales, deposited primarily as submarine fans, fan-deltas, and turbidite deposits. These are overlain by salt, thought to be equivalent to the Ezagna salt of Aptian age in the Gabon basin to the south. The synrift section is separated from the overlying postrift shale sequence of Late Cretaceous and Tertiary age by a major late Albian unconformity. The Douala basin has been explored for hydrocarbons intermittently over the last 25 years. Results show a distinct tendency for gas-proneness. The largest field recorded to date is the Sanaga Sud gas field, discovered in 1979, offshore, near the coastal city of Kribi.

  4. Basement configuration of KG offshore basin from magnetic anomalies

    NASA Astrophysics Data System (ADS)

    Subrahmanyam, V.; Swamy, K. V.; Raj, Neetha

    2016-04-01

    Marine magnetic anomalies along three representative profiles falling between shelf break and continent-ocean boundary in the offshore Krishna-Godavari basin were quantitatively interpreted for understanding the nature and structure of the magnetic basement using inversion technique. The interpretation of the anomalies shows that the magnetic basement lies deeper than the base of the sediments, i.e., acoustic basement identified by the seismic studies. This interpretation also shows that the magnetic basement is faulted along the NW-SE direction with the upthrown side lying to the north of the anomaly trend of this region. The coincidence of magnetizations observed through the present interpretation with that of charnockites of neighbouring EGMB and onshore K-G basin areas indicates that EGMB geology (charnockites, granitic gneiss, etc.) extends up to COB in the offshore K-G basin.

  5. Southern Mozambique basin: most promising hydrocarbon province offshore eat Africa

    SciTech Connect

    De Buyl, M.; Flores, G.

    1984-09-01

    Recent offshore acquisition of 12,800 km (8,000 mi) of seismic reflection data, with gravity and magnetic profiles encompassing the southern half of the Mozambique basin, reveals new facets of the subsurface geology. Integrated interpretation of these new geophysical data with old well information results in the development of depositional and tectonic models that positively establish the hydrocarbon potential of the basin. The recent comprehensive interpretation affords the following conclusions. (1) Significant oil shows accompany wet gas discoveries suggest that the South Mozambique basin is a mature province, as the hydrocarbon associations imply thermogenic processes. (2) Super-Karoo marine Jurassic sequences have been encountered in Nhamura-1 well onshore from the application of seismic stratigraphy and well correlation. (3) Steeply dipping reflectors truncated by the pre-Cretaceous unconformity testify to significant tectonic activity preceding the breakup of Gondwanaland. Hence, preconceived ideas about the depth of the economic basement and the absence of mature source rocks of pre-Cretaceous age should be revised. (4) Wildcats in the vicinity of ample structural closures have not been, in retrospect, optimally positioned nor drilled to sufficient depth to test the viability of prospects mapped along a major offshore extension of the East African rift system delineated by this new survey.

  6. Neogene sequence stratigraphy, Nam Con Son Basin, offshore Vietnam

    SciTech Connect

    McMillen, K.J. ); Do Van Luu; Lee, E.K.; Hong, S.S. )

    1996-01-01

    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.

  7. Neogene sequence stratigraphy, Nam Con Son Basin, offshore Vietnam

    SciTech Connect

    McMillen, K.J.; Do Van Luu; Lee, E.K.; Hong, S.S.

    1996-12-31

    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.

  8. The 1911 Quadrant offshore Namibia; Exploration in a virgin basin

    SciTech Connect

    Holtar, E.; Forsberg, A.

    1995-08-01

    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.

  9. Deep Structure of the Kwanza Basin, offshore Angola

    NASA Astrophysics Data System (ADS)

    von Nicolai, C.; Scheck-Wenderoth, M.; Lewerenz, B.; Clausen, L.

    2009-04-01

    Due to its specific rheological behaviour the presence of salt in the stratigraphic succession of passive continental margins strongly influences the structural evolution of the latter. Although it is known that salt tectonics are closely tied to regional deformation the interplay of both processes in the geological evolution of passive continental margins is still not well understood. In this study we present preliminary results from a project aiming to decipher the interaction of regional tectonics (i.e. subsidence, uplift) and internal deformation processes (= salt tectonic movements) in the South Atlantic Kwanza Basin by construction of a margin-wide, crustal-scale 3D structural model, and subsequent reconstruction of the deformation history. The Kwanza Basin offshore Angola formed during the Early Cretaceous opening of the South Atlantic. After continental break-up restricted marine conditions caused the precipitation of evaporites during the Aptian followed by carbonate and finally clastic deposition from the Albian to the present. Numerous salt structures of different maturation and styles document intense deformation of the Kwanza Basin since rifting. It thus provides an ideal site to study salt mobilisation processes and their relation with regional tectonics. A first simple 3D model of the Southern part of the basin providing insight into its present state configuration was constructed by the combination of structural and gravimetric modelling. 2D seismic reflection data was used to determine the structural setting and the configuration of the stratigraphic units in the sedimentary and upper crustal part of the basin, whereas its deep structure was constrained by gravity modelling. The resulting geological model suggests a strong segmentation of the continental crust of the Southern Kwanza Basin characterised by a chain of basement horsts and deep sedimentary troughs.

  10. Offshore Beaufort-Mackenzie basin and Amauligak oil discovery

    SciTech Connect

    Sharpe, R.J.; Gurba, G.J.; Sleumer, B.H.G.

    1988-01-01

    A variety of complex structural styles and depositional environments host hydrocarbon accumulations in the offshore Beaufort-Mackenzie basin. At present, only one of these, the Amauligak field, appears large enough to serve as a lead project to spur commercial development of the area. All offshore Beaufort discoveries to date occur in sandstones ranging from Paleocene to Oligocene in age. All occur in deltaic or delta-derived sediments ranging from delta-plain deposits to submarine fan/turbidites. In the western Beaufort, sediments are deformed into a series of linear diapiric features interpreted to be thrusted anticlines, possible associated with strike-slip faulting. Similarly, the Tarsiut area immediately to the east is dominated by diapiric anticlines crosscut by a major east-west-trending fault, also possibly a strike-slip fault. In contrast, the central and eastern portions of the offshore Beaufort, where Amauligak is located, are characterized by growth faulting in the sand-rich Oligocene depocenter. To the north, in a basinward direction, unfaulted diapiric anticlines are draped by submarine fans. These structures may in part be related to the gravitational faults to the south. The Amauligak field is located in the growth fault province. It is contained with a large, south-dipping, simple fault-bounded structure in which hydrocarbons are trapped against the north-bounding listric fault. Sediments penetrated at Amauligak include more than 1,500 m of interbedded Oligocene sandstones and shales, the sandstones representing primarily delta-front deposits. Distinctive shale markers are the probable result of the switching of major deltaic lobes.

  11. Ambient Noise Tomography of the Huatung Basin Offshore Eastern Taiwan

    NASA Astrophysics Data System (ADS)

    Liu, Ruo-Shan; Huang, Tzu-Ying; Chen, Ying-Nien; Chen, Chin-Wu

    2016-04-01

    The island of Taiwan is a young and active orogenic belt resulting from the oblique subduction and collision between the Eurasian Plate and the Philippine Sea Plate, where the Philippine Sea Plate is converging northwesterly toward the Eurasian Plate at a rate of 81 mm/year. In Southern Taiwan, the Eurasian Plate is subducting eastward beneath the Philippine Sea Plate along the Manila Trench. Offshore northeastern Taiwan, on the other hand, the Philippine Sea Plate is subducting northward beneath the Eurasian Plate along the Ryukyu Trench. Between the Ryukyu Trench and Luzon Arc lies the Huatung Basin, a 4000 m deep ocean basin in the westernmost part of the western Philippine Sea Basin. The intertwined tectonic processes result in complex geological structures of Taiwan, from surface to the crust and uppermost mantle. Previous seismic tomographic studies have suggested the effects of collision and subduction on the tectonic structures beneath Taiwan, but the details remain elusive, especially in the crustal depth range, due to limited station coverage and earthquake sources. Recently, ambient noise analysis fills the gap by offering high resolution tomographic model at crustal depths, derived from frequency-dependent Rayleigh wave measurements using noise cross-correlations. A most recent ambient noise tomography of Taiwan has revealed the presence of distinct layered deformation pattern throughout the crust, indicating integrated effect of collision and subduction on the evolution of Taiwan orogeny. However, this study used only land station and thus did not resolve structure in the surrounding region of the island. In our work, we aim to expand such analysis to offshore eastern Taiwan, taking advantage of the data from an OBS network as part of the recent TAIGER experiment. We integrate the data of OBS with that of selected land stations along the east coast, deriving Rayleigh wave Green functions from cross-correlation between all available station pairs. We

  12. Gravity-driven structures and rift basin evolution: Rio Muni Basin, offshore equatorial West Africa

    SciTech Connect

    Turner, J.P.

    1995-08-01

    Offshore Equatorial Guinea, west Africa, gravity-driven nappes, more than 1 km thick and 15 km from head to toe, provide key evidence in reconstructing the late synrift: evolution of this part of the South Atlantic margin basin system. Furthermore, Aptian-Cenomanian carbonate and clastic rocks in the nappes` allochthonous hanging walls are attracting interest as a new exploration play in west Africa. The nappes exhibit a range of geometries that suggest they share many of the same deformation processes as thin-skin thrust and linked extensional fault systems. Not only are these structures significant in their own right, representing a rare example of gravity tectonics in the virtual absence of major halokinesis, but their presence may record an other-wise undetectable process active during the transition from a rift basin to a passive continental margin. A review of Equatorial Guinea in its pre-Atlantic configuration, alongside neighboring basins in Brazil (the Sergipe-Alagoas basin) and Gabon, suggests that gravity gliding was sustained by a relatively steep, westward paleoslope promoted by east-ward offset of the locus of thermal uplift from the rift basin (i.e., a simple shear model of basin formation). In contrast to gravity-driven structures in most postrift settings, the Equatorial Guinea nappes developed at the close of the Aptian-Albian synrift episode in response to a growing bathymetric deep caused by rapid subsidence outpacing restricted sedimentation.

  13. The Marlin and Albacora giant fields, Campos Basin, offshore Brazil

    SciTech Connect

    De Souza, J.M.; Scarton, J.C.; Candido, A.; Cora, C.A.G. )

    1990-09-01

    The Albacore and Marlim giant fields are located in the province of Campos basin, about 110 km (68 mi) offshore Cape Sao Tome, in water depths ranging from 200 m (656 ft) to 2,000 m (6562 ft). The Albacora field was discovered in September 1984 by the wildcat 1-RJS-297, drilled in 293 m (961 ft) of water. Subsequently, the wildcats 1-RJS-305 and 1-RJS-342 extended the field limits to deeper waters. The Albacora field is approximately 235 km{sup 2} (90 mi{sup 2}) in area, with an estimated volume of 4.5 billion bbl of oil in place. The Marlim field was discovered in February 1985 by the wildcat 1-RJS-219A, in a water depth of 853 m (2,800 ft). The Marlim field area is about 152 km{sup 2} (58 mi{sup 2}), and the latest estimate of oil in place is about 8.2 billion bbl. The Marlim complex encompasses Marlim field itself and the surrounding proved and potential areas known as East-of-, West-of-, and South-of-Marlim, respectively. The current estimated volume of oil in place in the Marlim complex is close to 13.9 billion bbl, with a total surface of about 350 km{sup 2} (135 mi{sup 2}). Oil production in the Albacora field comes from Lower Cretaceous (Albian) and Tertiary (Eocene, Oligocene, and Miocene) turbidite reservoirs. Oligocene turbidite sandstones are the potential reservoirs in the Marlim field. These deposits are genetically associated with sea level variations and are mainly composed of massive sandstones and, subordinately, of contourites. Both fields are structurally and stratigraphically controlled accumulations. Hydrocarbons are trapped in anticlines and/or faulted blocks associated with salt tectonics. Stratigraphic contributions result from sandstone bodies pinching out against shales and marls. The development of these fields has been supported by three-dimensional seismic data. The Albacora field is being gradually put on stream from shallower to deeper waters.

  14. Blending Instruction with Khan Academy

    ERIC Educational Resources Information Center

    Cargile, Lori A.

    2015-01-01

    Khan Academy, the free Web-based tutorial program, landed on the education landscape in about 2011, when it was featured on the popular weekly news show "60 Minutes." The program is now used worldwide by more than 10 million learners each month and is used in more than 29,000 classrooms in 216 countries. Are classroom teachers using the…

  15. Mio-Pliocene evolution of the Gharb Sub-Basin, offshore Morocco

    NASA Astrophysics Data System (ADS)

    Dmitrieva, Evelina; Gerard, Jean; Abdallah, Hussein

    2014-05-01

    This study focuses on the underexplored offshore Gharb Sub-Basin, which is part of the foreland Gharb-Prerif Basin. The Gharb- Prerif basin is bound to the north by thrust faults associated with the Rif Orogen; to the south, the basin onlaps the Moroccan Meseta. The Gharb Sub-Basin is situated in northwestern Morocco and extends westward into the adjoining offshore area of the Atlantic Ocean. The Gharb-Sub basin also corresponds to the western end of the Rifian corridor. During the Late Miocene, two corridors, the Rifian and Betic connected the Mediterranean and the Atlantic. During the Messinian however the Rifian is considered to be the most important corridor. The accretionary prism of the Rif orogeny, also referred to as the Prerifaine Nappe became unstable and collapsed during Late Miocene. This gravitational collapse and the related plastic deformation processes resulted in the formation of mixed extensional-compressional basins limited by listric faults, toe thrusts and shale ridges. 2D and 3D seismic data covering ca. 2200 km² and four wells with wireline and cutting samples are utilized in order to reconstruct the Miocene-Pliocene evolution of the western end of the Rifian corridor (Offshore Gharb Sub-basin). New biostratigraphic framework is generated, which gives new insights into time constrains and aids the reconstruction of the geometry and stratigraphy of the basin fill. Additionally the studied succession represents an exploration target. The Gharb-Sub basin is associated with a series of satellite extensional mini-basins that are filled with thick Upper Miocene (Upper Tortonian) to Pleistocene clastics. These mini-basins formed at the late stages of the Rif-Betic orogeny due to the collapse of the accretionary wedge at Tortonian-Messinian times. Late Miocene gravitational normal faulting and related growth generated subsidence and sedimentation into the mini-basins. This integrated study aims to provide better understanding of the offshore Gharb

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

    SciTech Connect

    Carswell, A.B. ); Koning, T. ); Hibbs, D.C. )

    1990-05-01

    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.

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

    SciTech Connect

    Abreu, V.S.

    1996-12-31

    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.

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

    SciTech Connect

    Abreu, V.S. )

    1996-01-01

    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.

  19. Geology and hydrocarbon accumulations, Columbus basin, offshore Trinidad

    SciTech Connect

    Leonard, R.

    1983-03-01

    The Columbus basin, on the eastern shelf of Trinidad, lies at the eastern extremity of a belt of severe deformation along the northern boundary of South America that has been affected by compressional and wrench tectonics in the Pliocene-Pleistocene. Two major structural trends are present in the Columbus basin: a series of ENE-trending anticlines and NNW-oriented normal faults. The basin was filled during the late Miocene to Holocene with sediments deposited by an ancestral Orinoco River draining a hinterland to the southwest. The Pliocene-Pleistocene section, which contains the hydrocarbon accumulations in the Columbus basin, was laid down in three coarsening-upward sedimentary sequences followed by a late Pleistocene transgressive sequence. Traps for hydrocarbon accumulation were formed by an easterly trending Pliocene-Pleistocene wrench system with associated ENE-oriented anticlines combined with NNW-oriented normal faults. Oil was sourced in the late Miocene lower Cruse Formation, whereas gas was derived both from Pliocene-Pleistocene pro-delta shales and as a late high temperature phase of lower Cruse hydrocarbon generation. The NNW faults formed migration conduits from the oil source rock to Pliocene-Pleistocene reservoirs. The temporal relationship of faulting to oil generation is a major factor affecting the distribution of oil and gas. The size of hydrocarbon accumulations is limited to some extent by a lack of an effective hydrocarbon seal, particularly in the western half of the basin.

  20. Geology and hydrocarbon accumulations, Columbus Basin, Offshore Trinidad

    SciTech Connect

    Leonard, R.

    1983-07-01

    The Columbus basin, situated on the eastern shelf of Trinidad, lies at the eastern extremity of a belt of severe deformation along the northern boundary of South America that has been affected by compressional and wrench tectonics in Pliocene-Pleistocene time. Two major structural trends are present in the Columbus basin: a series of east-northeast trending anticlines and northnorthwest oriented normal faults. The basin was filled during late Miocene to Holocene time with sediments deposited by an ancestral Orinoco River draining a hinterland to the southwest. The Pliocene-Pleistocene section, which contains the hydrocarbon accumulations in the Columbus basin, was deposited in three coarseningupward sedimentary sequences followed by a late Pleistocene transgressive sequence. Traps for hydrocarbon accumulation were formed by an easterly trending Pliocene-Pleistocene wrench system with associated east-northeast-oriented anticlines combined with north-northwest-oriented normal faults. Oil was sourced in the late Miocene lower Cruse Formation, whereas gas was derived both from Pliocene-Pleistocene pro-delta shales and as a late high-temperature phase of lower Cruse hydrocarbon generation. The northnorthwest faults formed migration conduits from the oil source rock to Pliocene-Pleistocene reservoirs. The temporal relationship of faulting to oil generation is a major factor affecting the distribution of oil and gas. The size of hydrocarbon accumulations is limited to some extent by a lack of an effective hydrocarbon seal, particularly in the western half of the basin.

  1. Sedimentary fill and stratigraphic traps of Porcupine basin, offshore Ireland

    SciTech Connect

    Macurda, D.B. Jr.

    1986-05-01

    The Porcupine basin, off the southwest coast of Ireland, is a triangular north-south re-entrant into the present-day continental shelf. This aulacogen was formed in the Jurassic during the opening of the North Atlantic. A seismic stratigraphic investigation of the southern part of the basin has shown the complex evolution of the sedimentary fill from shallow to deep water facies, resulting in several stratigraphic traps. The central axis of the basin is dominated by a volcanic ridge. Part of the early sedimentary fill was intermittently covered by volcanic flows. The final stage of thin initial siliciclastic infill was the development of an extensive alluvial fan or fan-delta complex along the eastern basin margin. Aerially extensive carbonate sedimentation occurred during the Cretaceous, including a north-south reef tract more than 20 km wide in the eastern part of the basin. Increased subsidence resulted in the deposition of deep water siliciclastics in the Tertiary. The most prominent of these is a series of lower Tertiary submarine fans that were sourced from the western, northern, and eastern margins of the aulacogen. The early portions of the fans correlate well basin-wide; their later history is much more complex, with younger lobes up to 25 km wide developing south of their precursors. Subsequent onlap fill deposits provide an excellent seal. Sedimentation in the late Tertiary has included both high-energy and low-energy deep water deposits. The complex fill of the aulacogen has set up several stratigraphic plays, including carbonate reefs, alluvial fans of fan deltas, and submarine fans. Seismic amplitude anomalies in the latter suggest the heat flow has been sufficient to generate hydrocarbons to fill some of the traps.

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

    SciTech Connect

    Fraser, A.J.; Matthews, S.J.; Lowe, S.; Todd, S.P.; Simon, P. Peel, F.J.

    1996-12-31

    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.

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

    SciTech Connect

    Fraser, A.J.; Matthews, S.J.; Lowe, S.; Todd, S.P.; Simon, P. Peel, F.J. )

    1996-01-01

    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.

  4. Seismo and sequence stratigraphy of Cenozoic units of the Morondava Basin, offshore western Madagascar

    NASA Astrophysics Data System (ADS)

    Kaufmann, Dirk; Stollhofen, Harald; Klimke, Jennifer; Franke, Dieter

    2015-04-01

    The N-S trending Morondava Basin extends in width from western onshore Madagascar over about 350 km westwards to the offshore Davie Ridge in the Mozambique Channel. Although basin formation was initiated during Karoo times, the main basin evolution took place during Jurassic rifting and subsequent drifting until middle Cretaceous as a result of Gondwana breakup (Geiger et al., 2004). Contemporaneous to the separation of India and Madagascar widespread flood basalts were emplaced during the late Cretaceous (Storey et al., 1995). Present knowledge of the Morondava Basin is mainly based on outcrop studies, seismic surveys and borehole information (e.g. Geiger et al., 2004), gathered in western onshore Madagascar, although the fast majority of the basin, including its depocenter is located offshore in the Mozambique Channel, now at up to 3,500 m water depth. Almost all of the recent offshore studies of the Morondava Basin rely on industrial data but up to date publications of exploration results are generally rare and mostly anonymized. Our study aims to extend knowledge, particularly on the offshore seismic and sequence stratigraphy of the Morondava Basin. A key question is also to test the proposed tectonic stability of the Davie Ridge over the last 40 Ma. For this purpose 12 seismic profiles and bathymetric data, acquired in early 2014 by RV SONNE, are interpreted. Most of the profiles cover the distal deep marine areas of the northern Morondava Basin between the Davie Ridge and the shelf break of Madagascar. Top Cretaceous, Top Eocene, Top Oligocene, the Middle Miocene Unconformity and the Base Pliocene, are mapped as major seismic marker horizons. Especially shelf and slope sedimentary units are important resources to reconstruct the tectonostratigraphic basin evolution. At the continental slope diffuse to chaotic seismic pattern of Miocene and younger age are identified which are subdivided by laterally continuous, high frequency reflectors with a higher

  5. Deep seismic reflection profiling of sedimentary basins offshore Brazil: Geological objectives and preliminary results in the Sergipe Basin

    NASA Astrophysics Data System (ADS)

    Mohriak, Webster Ueipass; Lira Rabelo, JoséHenrique; De Matos, Renato Darros; De Barros, Mozart C.

    1995-12-01

    The first deep seismic reflection profiles offshore Brazil were acquired in Campos Basin and processed to 10 s TWT in 1984. Starting in 1989, Petrobrás acquired an extensive data set of deep seismic profiles using special acquisition equipment capable of effectively penetrating through the sedimentary layers and imaging the whole crustal architecture. These deep (18 s TWT) seismic reflection profiles extend across the Atlantic-type marginal basins, from the platform to the deepwater province, presently considered frontier regions for petroleum exploration. This work addresses the geological objectives of a deep seismic profile in the Sergipe Basin and discusses the results obtained by integrating regional seismic, gravity and magnetic data. When combined, these data provide evidence that deep seismic reflectors observed in the Sergipe Basin are related to intracrustal-upper mantle structures rather than sedimentary features. The deep seismic reflection profile in the Sergipe Basin also suggests that, rather than a non-volcanic passive margin, the deepwater extension of this basin is marked by several magmatic structures, including thick wedges of seaward-dipping reflectors and volcanic plugs. These magmatic features are associated with basinforming processes resulting from lithospheric extension during the breakup of Gondwana in the Early Cretaceous and subsequent emplacement of oceanic crust. These results are compared to the crustal scale structures observed in the Campos Basin, in the southeastern margin of Brazil. The interpretation of the deep structure of these basins indicates that final separation between the South American and African plates formed passive margins characterized by different patterns of crustal attenuation underlying the rift blocks.

  6. Seismic sequence stratigraphy of the Lower Congo, Kwanza, and Benguela Basins, offshore Angola, Africa

    NASA Astrophysics Data System (ADS)

    Schollnberger, Elle Marie

    2001-07-01

    Sequences are recognized throughout the geologic record. The Angolan margin provides an excellent opportunity to examine the factors that control the deposition and preservation of sediments in sequences, as well as the factors that create the erosion or non-deposition along sequence boundaries. The Angolan sequences can be compared to global sequence charts and used to investigate the effects of local events versus global events on the area's sequences. Using seismic sequence stratigraphic principles, a 2D regional seismic data set covering three basins offshore Angola, the Lower Congo, Kwanza, and Benguela Basins, was interpreted. Sequences and their unconformities were correlated within each basin as well as between basins. Major sequences could be interpreted throughout and between the three basins with a high degree of confidence. Additional sequences within these major sequences were interpreted within a basin, but could not be correlated to the adjacent basin with a high degree of confidence. Detailed interpretation of the sequence stratigraphic significance of each reflector was performed on three profiles, one for each basin. Chronostratigraphic charts were constructed using the detailed interpretation of the profiles. Within the interpreted sequence stratigraphic framework, the timing and mechanics of the formation of salt structures was examined. The Angolan basins contain a variety of salt tectonic features. The reflectors of strata adjacent to the salt features were used to determine the timing and mechanics of the salt structure formation. This study accomplished several objectives. The tectonic evolution of the Angolan margin was reviewed. This study established a sequence stratigraphic framework for Angola. The process of deposition and preservation of sediments as depositional sequences was examined. The sequences were compared with the global sequence charts as well as with eustatic, tectonic, and oceanic circulation events. The formation of the

  7. Evaluating the Role of Hydrocarbon Seepage in Carbonate Mound Formation (Offshore Ireland) using Basin Modelling

    NASA Astrophysics Data System (ADS)

    Naeth, J.; di Primio, R.; Horsfield, B.; Shannon, P.; Bailey, W. R.; Henriet, J. P.

    2003-04-01

    The goal of this project was to assess whether deep water coral mound growth on the continental slope of the north Atlantic could be related to active hydrocarbon leakage. The objects of interest are numerous buried and non-buried carbonate mounds, consisting mainly of corals, carbonate crusts and fine grained clastic sediments in the Porcupine Basin, which is located on the eastern Atlantic continental slope 200 km offshore Ireland and contains the sub-commercial Connemara oil field. To evaluate the possible link between hydrocarbon leakage and mound growth we used 2D and 3D basin modelling in combination with geochemical analysis of sediments from gravity cores. A total of 5 intersecting seismic lines were used as a basis for 2D modelling of basin evolution, hydrocarbon generation and migration. Data from six exploration wells were used for calibration of the basin burial and thermal history using vitrinite reflectance, bottom hole temperatures and apatite fission track data. 3D basin modelling was performed using data provided by UCD in the northern part of the Porcupine Basin. The results of this study indicate that a link between modelled hydrocarbon leakage and carbonate mound growth is possible both in the Belgica mound province on the eastern flank of the basin where stratigraphic pinch outs of carrier beds can lead to the localised leakage of hydrocarbons to the seafloor, as well as in the Hovland Magellan mound area in the northern half of the Porcupine Basin, where small-scale structural closures mapped on the main Miocene surfaces correlate roughly to observed mound locations. This study demonstrates the applicability of basin modelling in testing and identifying geologic processes related to geosphere/biosphere interactions.

  8. Geology of the undeveloped oil and gas fields of Central Offshore Santa Maria Basin, California

    SciTech Connect

    Milton, J.D. ); Edwards, E.B. ); Heck, R.G. )

    1996-01-01

    Two prominent subsurface structural features of the Central Offshore Santa Maria Basin are the Hosgri fault system and the associated anticlinal fold trend. Exploratory drilling and 3D seismic mapping have delineated a series of oil and gas fields along this trend which underlie four federal units and one non-unitized lease. The units are named after local geography and are called the Lion Rock, Point Sal, Purisima Point and Santa Maria Units. The individual lease, OCS P-0409, overlies the San Miguel field. The Hosgri fault system trends northwest-southeast and effectively forms the eastern boundary of the oil and gas province. Lying semi-parallel with the fault are several anticlinal culminations which have trapped large volumes of oil and gas in the fractured Montery Formation. The Monterey is both source and reservoir rock, averaging 300 meters n thickness throughout the Central Basin. Development of the Monterey Formation as a reservoir rock was through diagensis and tectonism with resulting porosities-from 15 to 20% and permeability up to one Darcy. These parameters coupled with a high geothermal gradient facilitate the inflow rates of the viscous Monterey oil. Some 24 exploration and delineation wells have been drilled in this area and tested at rates ranging from a few hundred to several thousand barrels per day. Estimated oil reserves in the Central Offshore Santa Maria Basin total approximately 1 billion barrels.

  9. Geology of the undeveloped oil and gas fields of Central Offshore Santa Maria Basin, California

    SciTech Connect

    Milton, J.D.; Edwards, E.B.; Heck, R.G.

    1996-12-31

    Two prominent subsurface structural features of the Central Offshore Santa Maria Basin are the Hosgri fault system and the associated anticlinal fold trend. Exploratory drilling and 3D seismic mapping have delineated a series of oil and gas fields along this trend which underlie four federal units and one non-unitized lease. The units are named after local geography and are called the Lion Rock, Point Sal, Purisima Point and Santa Maria Units. The individual lease, OCS P-0409, overlies the San Miguel field. The Hosgri fault system trends northwest-southeast and effectively forms the eastern boundary of the oil and gas province. Lying semi-parallel with the fault are several anticlinal culminations which have trapped large volumes of oil and gas in the fractured Montery Formation. The Monterey is both source and reservoir rock, averaging 300 meters n thickness throughout the Central Basin. Development of the Monterey Formation as a reservoir rock was through diagensis and tectonism with resulting porosities-from 15 to 20% and permeability up to one Darcy. These parameters coupled with a high geothermal gradient facilitate the inflow rates of the viscous Monterey oil. Some 24 exploration and delineation wells have been drilled in this area and tested at rates ranging from a few hundred to several thousand barrels per day. Estimated oil reserves in the Central Offshore Santa Maria Basin total approximately 1 billion barrels.

  10. Gas Hydrate Deposits in the Cauvery-Mannar Offshore Basin, India

    NASA Astrophysics Data System (ADS)

    Dewangan, P.

    2015-12-01

    The analysis of geophysical and coring data from Mahanadi and Krishna-Godavari offshore basins, eastern continental margin of India, has established the presence of gas hydrate deposits; however, other promising petroliferous basins are relatively unexplored for gas hydrates. A collaborative program between GSI/MoM and CSIR-NIO was formulated to explore the Cauvery-Mannar offshore basin for gas hydrate deposits (Fig. 1a). High quality multi-channel reflection seismics (MCS) data were acquired with 3,000 cu. in airgun source array and 3 km long hydrophone streamer (240 channels) onboard R/V Samudra Ratnakar for gas hydrate studies. Other geophysical data such as gravity, magnetic and multibeam data were also acquired along with seismic data.After routine processing of seismic data, the bottom simulating reflectors (BSRs) are observed in the central and north-eastern part of the survey area. The BSRs are identified based on its characteristic features such as mimicking the seafloor, opposite polarity with respect to the seafloor and crosscutting the existing geological layers (Fig. 1b). At several locations, seismic signatures associated with free gas such as drop in interval velocity, pull-down structures, amplitude variation with offset (AVO) and attenuation are observed below the BSRs which confirm the presence of free gas in the study area. Acoustic chimneys are observed at some locations indicating vertical migration of the free gas. The observed seismic signatures established the presence of gas hydrates/free gas deposits in Cauvery-Mannar basin. Interestingly, BSRs appear to be distributed along the flanks of submarine canyon indicating the influence of geomorphology on the formation and distribution of gas hydrates.

  11. West Atlantic mesozoic carbonates: comparison of Baltimore Canyon and offshore Nova Scotian basins

    SciTech Connect

    Eliuk, L.S.; Cearley, S.C.; Levesque, R.

    1986-05-01

    Results of exploratory drilling, by Shell Offshore Inc., and its partners, of the Late Jurassic-Early Cretaceous carbonate margin of the Baltimore Canyon (BC) basin can be interpreted directly from the better understood, time-equivalent Nova Scotian (NS) basin stratigraphy. The BC paleomargin was constructed in a depositional cycle of three successive stages: Oxfordian-early Kimmeridgian progradation, Kimmeridgian-Berriasian aggradation, Berriasian-Valanginian drowning. The upper two stages in NS are the Baccaro and Artimon members of the Abenaki formation. The progradation of the lower sequence in BC results from high clastic input and has a parallel (not age equivalent) in NS only in proximity to the Sable Island paleodelta. Both basins have similar, complementary, shelf-edge environments that form a single water-depth-controlled biotic zonation. This zonation is: shallow-water stromatoporoid-hexacoral biostromes and reefs; deeper water stromatactis and thrombolitic mud mounds; and deep-water lithistid sponge reefs. Associated environments are oncolitic reef flats, reef-apron skeletal sands, slope reef debris from sponge and coral reefs, and back-reef mollusk-rich skeletal and skeletal-oolitic sands. Major differences between the basins are the pinnacle reefs of BC and the contrast between the mud-rich skeletal and nonskeletal megafacies of NS versus the dominantly skeletal sand-rich BC sediments. The higher subsidence rates of BC may explain both differences.

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

    SciTech Connect

    Van Wyk, N.J.S.

    1989-03-01

    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 high-resolution seismic coverage and borehole control supported the study. The interplay of diminishing rift tectonics, thermal cooling, and inferred eustatic variations in global sea level produced a distinctive series of repetitive cycle depositional sequences. As many as 10 cyclic sequences and megasequences, deposited between the mid-Valanginian and lower Santonian, can be recognized within resolution limits of regional seismic profiles. Various elements of lowstand systems tracts within these sequences appear to contain potential reservoirs. Highly erosional (type 1) unconformities, commonly exhibiting incised valleys and canyons, provide surfaces on which (1) mounded and sheetlike submarine/basin-floor fans, (2) submarine channel fill and associated mounds and fans, and (3) prograding deltaic/coastal lowstand wedges were deposited. These fans, channel fills, and wedges are top sealed and sourced by transgressive shales and marine condensed sections, deposited at a time of regional transgression of the shoreline. One discovery well and various reservoir-quality sandstones occurring at predicted stratigraphic levels in other wells support the application of the sequence-stratigraphic concepts to hydrocarbon exploration.

  13. Multiphase Fault Evolution in a Rotational Margin Setting: Offshore Sirte Basin, Libya

    NASA Astrophysics Data System (ADS)

    Maddock, Paul; McCaffrey, Ken; Imber, Jonathon

    2013-04-01

    The aims of this study are to present a new structural interpretation of a well-calibrated regional 2D seismic dataset to constrain the timing and style of faulting in the Sirte embayment, offshore Libya, a Mesozoic-Cenozoic extension of the Sirte basin onshore north Africa. Due to rotation of the African continent since the Mesozoic, present-day fault orientations are not the same as during fault formation at various times since the early Palaeozoic. The approach has therefore been to integrate a structural model with published plate tectonic reconstructions in order to progressively restore fault orientations throughout the evolution of the Sirte embayment. Multiple phases of rifting can be observed in the offshore area, with major faulting episodes during the Aptian-Albian, Upper Cretaceous, mid-Eocene and Oligocene. Paleozoic basement structures have a dominant role in controlling the locations of later faults. The model shows how pre-existing structures have been reactivated during the main Cretaceous basin-forming episode, with some deeply-rooted basement faults remaining active into the mid-late Cretaceous. The orientation of basement faults with respect to the inferred regional stress direction appears to be a key influence on the type of faulting observed. In many parts of the Sirte Embayment, active faulting during the later Mesozoic is concentrated in fault zones directly above, or in the immediate hanging wall of older, deeper faults. The dominant stress field since the Cretaceous is consistent with the onshore Sirte trend with extension generally to the NE-SW giving NW-SE striking faults and fault zones. The orientation of pre-Mesozoic faults can be shown to have rotated anti-clockwise by 40° between formation and Cretaceous deformation, with a further 17° to the present day giving a total rotation of 57°. While the present day onshore trend of NW-SE horst and graben blocks has the greatest influence on the structure of the Sirte embayment

  14. Geologic implications of gas hydrates in the offshore of India: Krishna-Godavari Basin, Mahanadi Basin, Andaman Sea, Kerala-Konkan Basin

    USGS Publications Warehouse

    Kumar, Pushpendra; Collett, Timothy S.; Boswell, Ray; Cochran, James R.; Lall, Malcolm; Mazumdar, Aninda; Ramana, Mangipudi Venkata; Ramprasad, Tammisetti; Riedel, Michael; Sain, Kalachand; Sathe, Arun Vasant; Vishwanath, Krishna; Yadav, U.S.

    2014-01-01

    NGHP-01 yielded evidence of gas hydrate from downhole log and core data obtained from all the sites in the Krishna–Godavari Basin, the Mahanadi Basin, and in the Andaman Sea. The site drilled in the Kerala–Konkan Basin during NGHP-01 did not yield any evidence of gas hydrate. Most of the downhole log-inferred gas hydrate and core-recovered gas hydrate were characterized as either fracture-filling in clay-dominated sediments or as pore-filling or grain-displacement particles disseminated in both fine- and coarse-grained sediments. Geochemical analyses of gases obtained from sediment cores recovered during NGHP-01 indicated that the gas in most all of the hydrates in the offshore of India is derived from microbial sources; only one site in the Andaman Sea exhibited limited evidence of a thermogenic gas source. The gas hydrate petroleum system concept has been used to effectively characterize the geologic controls on the occurrence of gas hydrates in the offshore of India.

  15. Basin Analysis and Petroleum System Characterisation of Western Bredasdorp Basin, Southern Offshore of South Africa: Insights from a 3d Crust-Scale Basin Model - (Phase 1)

    NASA Astrophysics Data System (ADS)

    Sonibare, W. A.; Scheck-Wenderoth, M.; Sippel, J.; Mikeš, D.

    2012-04-01

    In recent years, construction of 3D geological models and their subsequent upscaling for reservoir simulation has become an important tool within the oil industry for managing hydrocarbon reservoirs and increasing recovery rate. Incorporating petroleum system elements (i.e. source, reservoir and trap) into these models is a relatively new concept that seems very promising to play/prospect risk assessment and reservoir characterisation alike. However, yet to be fully integrated into this multi-disciplinary modelling approach are the qualitative and quantitative impacts of crust-scale basin dynamics on the observed basin-fill architecture and geometries. The focus of this study i.e. Western Bredasdorp Basin constitutes the extreme western section of the larger Bredasdorp sub-basin, which is the westernmost depocentre of the four southern Africa offshore sub-basins (others being Pletmos, Gamtoos and Algoa). These basins, which appear to be initiated by volcanically influenced continental rifting and break-up related to passive margin evolution (during the Mid-Late Jurassic to latest Valanginian), remain previously unstudied for crust-scale basin margin evolution, and particularly in terms of relating deep crustal processes to depo-system reconstruction and petroleum system evolution. Seismic interpretation of 42 2D seismic-reflection profiles forms the basis for maps of 6 stratigraphic horizons which record the syn-rift to post-rift (i.e. early drift and late drift to present-day seafloor) successions. In addition to this established seismic markers, high quality seismic profiles have shown evidence for a pre-rift sequence (i.e. older than Late Jurassic >130 Ma). The first goal of this study is the construction of a 3D gravity-constrained, crust-scale basin model from integration of seismics, well data and cores. This basin model is constructed using GMS (in-house GFZ Geo-Modelling Software) while testing its consistency with the gravity field is performed using IGMAS

  16. Flip or Flop: Are Math Teachers Using Khan Academy as Envisioned by Sal Khan?

    ERIC Educational Resources Information Center

    Cargile, Lori A.; Harkness, Shelly Sheats

    2014-01-01

    Khan Academy (KA) is a free web-based intelligent tutor, which has been featured in countless media outlets for its potential to change mathematics instruction. The founder and executive director, Salman Khan, recommends that KA be used to personalize instruction, freeing up class time for engaging high yield activities like student discourse and…

  17. Delineating the northern part of the Socotra Basin, offshore Korea, using marine magnetics

    NASA Astrophysics Data System (ADS)

    Suh, M.; F. Abdallatif, T.; Han, J.; Choi, S.; Oh, J.

    2005-12-01

    A marine magnetic survey was carried out in and around the northern part of Socotra Basin, offshore Korea (31°42'32″ 32°46'29″N and 123°56'26″ 125°49'16″E), in order to better delineate its northern and eastern boundaries. Analyses of the observed magnetic field and estimation of the basement depth were used to assess these boundaries. The power spectrum and the three-dimensional analytical signal methods were used for depth estimation and to reconstruct basement configuration. Estimated depths resulting from the power spectrum method range from 1.5 to 6.0 km for deep sources (basement troughs), and from 0.3 to 1.7 km for shallower sources (basement peaks). An isopach map shows that the sedimentary sequence varies from 1.4 to 6.0 km in thickness. Estimated depths from the analytic signal method fluctuate in the range 1.2 6 km. The results of the observed field analysis and depth estimation indicate good agreement with the formerly proposed eastern boundary but disagreement with the northern boundary. The findings suggest either an extension of the Socotra Basin or the existence of other sub-basins possibly interconnected with the study area.

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

    SciTech Connect

    Lee, G.H.; Watkins, J.S.

    1996-12-31

    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.

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

    SciTech Connect

    Lee, G.H. ); Watkins, J.S. )

    1996-01-01

    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.

  20. 3-D magnetotelluric image of offshore magmatism at the Walvis Ridge and rift basin

    NASA Astrophysics Data System (ADS)

    Jegen, Marion; Avdeeva, Anna; Berndt, Christian; Franz, Gesa; Heincke, Björn; Hölz, Sebastian; Neska, Anne; Marti, Anna; Planert, Lars; Chen, J.; Kopp, Heidrun; Baba, Kiyoshi; Ritter, Oliver; Weckmann, Ute; Meqbel, Naser; Behrmann, Jan

    2016-06-01

    The Namibian continental margin marks the starting point of the Tristan da Cunha hotspot trail, the Walvis Ridge. This section of the volcanic southwestern African margin is therefore ideal to study the interaction of hotspot volcanism and rifting, which occurred in the late Jurassic/early Cretaceous. Offshore magnetotelluric data image electromagnetically the landfall of Walvis Ridge. Two large-scale high resistivity anomalies in the 3-D resistivity model indicate old magmatic intrusions related to hot-spot volcanism and rifting. The large-scale resistivity anomalies correlate with seismically identified lower crustal high velocity anomalies attributed to magmatic underplating along 2-D offshore seismic profiles. One of the high resistivity anomalies (above 500 Ωm) has three arms of approximately 100 km width and 300 km to 400 km length at 120° angles in the lower crust. One of the arms stretches underneath Walvis Ridge. The shape is suggestive of crustal extension due to local uplift. It might indicate the location where the hot-spot impinged on the crust prior to rifting. A second, smaller anomaly of 50 km width underneath the continent ocean boundary may be attributed to magma ascent during rifting. We attribute a low resistivity anomaly east of the continent ocean boundary and south of Walvis Ridge to the presence of a rift basin that formed prior to the rifting.

  1. Onshore and offshore basins of northeast Libya: Their origin and hydrocarbon potential

    SciTech Connect

    Shegewi, O.M.

    1992-01-01

    A comprehensive data base of more than 3000 km of seismic lines, gravity and magnetic data, more than 30 subsurface well logs, and surface geology data were utilized to examine and interpret the sedimentary and tectonic history of the onshore and offshore parts of Northeast Libya and their hydrocarbon potential. The Dernah-Tobruk and Benghazi offshore basins form the northern parts of the study area. The Cyrenaica Stable Platform represents the southern parts. The Sirual Trough stretches E-W and opens into the Antelat Trough in the west. Between these elements is the uplifted areas of the Al Jabal Al Akhdar. Six principal tectonic phases were responsible for the formation and development of these structural elements: the pre-Mesozoic phase, the Triassic-Jurassic rifting phase, the Neocomian and the Aptian-Albian renewed rifting phases, the Late Cretaceous-Paleocene uplifting phase; and the Eocene-Middle Oligocene rifting phase. Oceanic crust of probable Aptian-Albian age is evident on the seismic lines north of the master fault marking the southern boundary of the rift separating the north African plate and Apulia. The western boundary of the Dernah High displayed clearly NE-SW strike-slip movement of these trajectories. Oceanic crust is also present west of the Dernah High. Positive gravity and magnetic anomalies traverse parallel to the boundary of this oceanic plate Mesogea. The prerequisites for commercial hydrocarbon production are present in abundance. Reservoirs ranging in age from Paleozoic clastics in the Cyrenaica Stable Platform to Mesozoic and Tertiary carbonates throughout the rest of the region. Several deep sites for the generation of hydrocarbons were also present, including the rifted northern parts of the Dernah-Tobruk basin, the Antelat Trough and the Cyrenaica Passive Margin. The Cretaceous and Tertiary section in the study area contain several potential seal rocks. Several potential trap types are also present.

  2. Petroleum geology of the deltaic sequence, Rio Del Rey basin, offshore Cameroon

    SciTech Connect

    Coughlin, R.M.; Bement, W.O.; Maloney, W.V. )

    1993-09-01

    The Rio Del Rey Basin of offshore Cameroon comprises the easternmost portion of the Niger delta complex. In the delta flank setting, the overall package is thinner and stratigraphic correlation simpler than in the depocenter to the west so the distribution of reservoirs and seals is well defined. Productive reservoirs are shallow, typically less than 2000 m, and mostly hydropressured to slightly overpressured. Reservoir properties generally are excellent and seismic bright-spot technology has played a major role in exploration and development efforts. Rio Del Rey is characterized by three main structural styles from north to south: (1) detachment-based growth faults, (2) highly faulted, mobile shale cored domes and ridges, and (3) toe thrusts and folds. Virtually all individual traps are fault dependent and lack of sufficient internal seals in sand-rich wave-dominated deltaic sequences can limit the objective window. Most fields are downthrown fault traps in which hanging-wall reservoirs are effectively sealed against older prodelta and marine shales. All large oil fields are located in the dome and ridge province and are potential analogs for similar structures now being explored on the upper slope off Nigeria. The best quality source rocks identified thus far are Paleocene to Eocene marine shales. Oil vs. gas distribution in the basin is a function of variations in the kerogen type, organic richness, and maturity of these source rocks. A significant quantity of the gas found to date in Rio Del Rey is biogenic in origin. The Cameroon charge model may aid in better understanding hydrocarbon distribution on offshore Nigeria, where the Miocene deltaic section is much thicker and potential Paleocene-Eocene source rocks likely are unpenetrated. The shallow deltaic play in Cameroon is relatively mature. Future exploration likely will focus on identifying deeper, nonbright-spot-supported opportunities including potential stratigraphic traps.

  3. Toward a One-World Schoolhouse: Interview with Sal Khan

    ERIC Educational Resources Information Center

    Pinkus, Ari

    2015-01-01

    Ten years ago, Salman Khan, with three degrees from MIT and an MBA from Harvard, agreed to help tutor his cousin Nadia, who was struggling in math. Using Yahoo's Doodle notepad, Khan offered Nadia a sequence of mini lessons designed to scaffold her learning. Over time, other friends and relatives heard about Khan's success and asked for similar…

  4. Reimagining Khan Analytics for Student Coaches

    ERIC Educational Resources Information Center

    Cunningham, Jim

    2015-01-01

    In this paper, I describe preliminary work on a new research project in learning analytics at Arizona State University. In conjunction with an innovative remedial mathematics course using Khan Academy and student coaches, this study seeks to measure the effectiveness of visualized data in assisting student coaches as they help remedial math…

  5. Regional maps of subsurface geopressure gradients of the onshore and offshore Gulf of Mexico basin

    USGS Publications Warehouse

    Burke, Lauri A.; Kinney, Scott A.; Dubiel, Russell F.; Pitman, Janet K.

    2013-01-01

    The U.S. Geological Survey created a comprehensive geopressure-gradient model of the regional pressure system spanning the onshore and offshore Gulf of Mexico basin, USA. This model was used to generate ten maps that included (1) five contour maps characterizing the depth to the surface defined by the first occurrence of isopressure gradients ranging from 0.60 psi/ft to 1.00 psi/ft, in 0.10-psi/ft increments; and (2) five supporting maps illustrating the spatial density of the data used to construct the contour maps. These contour maps of isopressure-gradients at various increments enable the identification and quantification of the occurrence, magnitude, location, and depth of the subsurface pressure system, which allows for the broad characterization of regions exhibiting overpressured, underpressured, and normally pressured strata. Identification of overpressured regions is critical for exploration and evaluation of potential undiscovered hydrocarbon accumulations based on petroleum-generation pressure signatures and pressure-retention properties of reservoir seals. Characterization of normally pressured regions is essential for field development decisions such as determining the dominant production drive mechanisms, evaluating well placement and drainage patterns, and deciding on well stimulation methods such as hydraulic fracturing. Identification of underpressured regions is essential for evaluating the feasibility of geological sequestration and long-term containment of fluids such as supercritical carbon dioxide for alternative disposal methods of greenhouse gases. This study is the first, quantitative investigation of the regional pressure systems of one of the most important petroleum provinces in the United States. Although this methodology was developed for pressure studies in the Gulf of Mexico basin, it is applicable to any basin worldwide.

  6. Regional comparison of syn- and post-rift sequences in salt and salt-free basins offshore Brazil and Angola/Namibia, South Atlantic

    NASA Astrophysics Data System (ADS)

    Strozyk, Frank; Back, Stefan; Kukla, Peter

    2015-04-01

    The large South Atlantic basins offshore South America and Africa record a highly variable syn- to post-breakup tectono-stratigraphic development. The present-day diversity in the structural and sedimentary architecture of the conjugate margins offshore southern Brazil, Namibia and Angola reflects variations in the interplay of a number of controlling factors, of which the most important are i) the structural configuration of each margin segment at the time of break-up, ii) the post break-up geodynamic history including tectonics and magmatism, and iii) variations in the type, quantity and distribution of sediment input to the respective margin segment. Particularly the basins around the Rio Grande Rise - Walvis Ridge volcanic complex show a pronounced tectono-stratigraphic asymmetry both along the respective continental margin and across the Atlantic. Only a few attempts exist to establish a regional tectono-stratigraphic correlation framework across the South Atlantic Ocean, mainly because of the lack of data across entire margin segments and limited resolution of basin wide geophysics. Still unresolved issues particularly concern the explanation of the basin-specific geological evolution of respective margin segments along the same continental margin, as well as the correlation of conjugate basins and margin segments across the Atlantic Ocean. In our study we present interpretations and first-pass restorations of regional 2D seismic-reflectivity data from the large basins offshore Brazil (Pelotas Basin, Santos Basin, Campos Basin, Espirito Santo Basin), and offshore Namibia and Angola (Walvis Basin, Namibe Basin, Benguela Basin, Kwanza Basin), which represent four adjacent pairs of conjugate basins on both sides of the South Atlantic. Results are used to document and compare on a basin-scale the contrasting styles of rift and post-rift settings during and after the continental breakup.

  7. Identifying potential gas accumulation sites from Oligocene overpressure data in the Qiongdongnan basin, offshore South China

    SciTech Connect

    Liu Funing )

    1993-05-01

    Overpressure in Oligocene formations in southern Qiongdongnan basin, offshore China, can be determined either by actual measurements in wells or by calculations using data derived from well logs and seismic surveys. The overpressure is mainly the result of undercompaction of Oligocene rocks during rapid loading by Pliocene and Quaternary sedimentation and of the subsequent thermal expansion of fluids in the Oligocene strata. Every formation possesses its own normal compaction trend (plot of shale-interval acoustic transit times vs. depth). The actual fluid pressures and potential pressures can be computed by the equilibrium-depth method. This method must be corrected for the thermal expansion of fluid. The pressure corrections are based on shale-interval transit times from well logs, interval velocities interpreted from vertical seismic profile (VSP) surveys, and stacking velocity from sonic log data of nearby wells. Gas generated from source rocks is assumed to have moved vertically from strata of higher hydraulic pressure potential to those of lower potentials and to have moved laterally and accumulated within areas where the contour closures of a gas equipotential hydraulic-pressure surface (U curves) have lower values. In the study area, the vicinity of the Yacheng gas field, the potential maps (U, gas, and V, water, maps) and hydraulic head profiles can be plotted from values derived either from actual pressure measurements or from calculations. These maps and profiles show prospective areas of gas accumulation. 5 refs., 10 figs., 1 tab.

  8. Control of salt tectonics by young basement tectonics in Brazil`s offshore basins

    SciTech Connect

    Szatmari, P.; Mohriak, W.

    1995-08-01

    The Campos basin (offshore SE Brazil) is one of the most successful areas of oil exploration in South America. Discovered 20 years ago, its production (500,000 b/d) and reserves (2.9 billion barrels) are second only to Venezuela`s. This richness is due, to a large extent, to intense salt tectonics and the abundance of turbidites. Reactivated basement structures onshore provide a unique opportunity to understand the role of young basement tectonics in controlling salt tectonics and petroleum occurrence. The mountains of SE Brazil, over 1500 m high, formed by the reactivation of late Precambrian thrust and wrench zones under E-W compression, presumably caused by Mid-Atlantic ridge push. Coastal mountain ranges, up to 3000 m high, are limited to the segment of the Atlantic between the Vitoria-Trindade hotspot chain and the Rio Grande Rise. The coastal ranges formed as this segment of oceanic crust and adjacent continental margin were pushed WSW along a reactivated Precambrian wrench zone. To the north of this segment, salt tectonics is mostly due to basinward sliding on a tilted salt layer. Along the coastal ranges, to this is added basinward escape of the salt from beneath prograding sediments derived from the rising mountains. Extension above the salt tends to be compensated by compression farther basinward. Salt canopies, frequent in the Gulf of Mexico, occur only near the Abrolhos hotspot, where high temperatures during volcanic activity sharply reduced the viscosity of the salt.

  9. Comparative structural reconstruction of the post-breakup succession in conjugated salt and salt-free basins offshore South-America and South-Africa

    NASA Astrophysics Data System (ADS)

    Strozyk, Frank; Back, Stefan; Kukla, Peter

    2013-04-01

    This project focuses on the post-breakup tectono-stratigraphic development of large offshore basins along the South American and African continental margins that record strongly varying post-rift sedimentary successions. The northernmost segment of the South Atlantic rift and salt basins is characterized by a pronounced asymmetry, with the Brazilian margin comprising narrower and deeper rift basins with less salt in comparison to the Congo-Gabon conjugate margin. Another important observation is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. In this study we show a regional comparison between the large basins offshore southern Brazil (Espirito Santo Basin, Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Lower Congo Basin, Kwanza Basin, Namibe Basin, Walvis Basin, etc). A sequential reconstruction of tectonic and stratigraphic elements of representative geological transects provides a comprehensive basin-to-basin documentation of the influence of key geological parameters controlling ocean and continental margin development. These include the subsidence development through time, sediment input, flux and storage patterns, salt vs. non-salt systems, carbonate-rich vs. clastics-dominated successions and finally major tectonic and magmatic events. Data from the salt basins indicate that salt-related tectonic deformation is amongst the prime controls for the non-uniform post-rift margin development.

  10. Complex intrasalt deformation in the Santos Basin, offshore Brazil: the role of density inversion

    NASA Astrophysics Data System (ADS)

    Dooley, Tim; Jackson, Chris; Jackson, Martin; Hudec, Mike; Rodriguez, Clara

    2016-04-01

    Understanding intrasalt structure may elucidate the fundamental kinematics and, ultimately, the mechanics of diapir growth. However, there have been relatively few studies of the internal structure of salt diapirs outside the mining industry because their cores are only partly exposed in the field and poorly imaged in seismic reflection data. 3D seismic reflection from the Santos Basin, offshore Brazil reveal enigmatic allochthonous salt sheets of older evaporites emplaced above an overlying stratified evaporite sequence. Seismic-stratigraphic observations form the basis for a kinematic model invoking: (i) initial inward flow and thickening of the lower mobile salt within the rising wall, and arching of stratified overburden; (ii) breaching of the overburden, ascent of mobile lower evaporites along single or multiple feeders, and emplacement of upper-wall sheets or canopies; and (iii) later diapir squeezing due to regional shortening. We designed and ran physical models to explain how and why these structures occur, and to provide a mechanical basis for our kinematic model. Our first two models simulated salt having uniform internal density, with walls growing by (i) initially symmetric differential loading; and (ii) initially symmetric differential loading plus shortening. These models reproduced anticlines and injection folds seen in the simpler deformed walls in the Santos Basin. However, neither model reproduced the most complex structures (e.g. allochthonous intrusions, steep feeders, recumbent synclines) seen within the Santos evaporites. Thus, we argue differential loading and shortening alone are insufficient to generate these complex structures. In our third model, a less-dense lower evaporite was overlain by denser upper evaporites, similar to the density structure found in Santos Basin wellbores. In this model the wall rose solely by differential loading, with the lower mobile unit breaching the overlying stratified evaporites to form vertical diapirs

  11. Deformation-driven fluid escape in the Levant Basin, offshore southern Israel

    NASA Astrophysics Data System (ADS)

    Eruteya, Ovie Emmanuel; Waldmann, Nicolas; Reshef, Moshe; Ben-Avraham, Zvi

    2016-04-01

    Submarine fluid emissions are global phenomena, which can be inferred from the presence of seafloor morphologies (e.g. pockmarks, mud volcanoes) occurring in various geological settings. However, despite the Levant Basin been a prolific hydrocarbon province, only a paucity of fluid escape morphologies have been identified on the present-day seafloor. In this study, we present a detailed analysis of a newly available high-resolution 3D seismic reflection dataset from offshore southern Israel. Evidences of subsurface fluid plumbing and escape are manifested here as present-day seafloor pockmarks, paleo-pockmarks, pipe structures and enhanced reflectivity patterns. Interestingly, these pockmarks are situated on and around bathymetric highs, which are ridges related to the Palmachim Disturbance. Our initial results show the fluid flow structures are spatially localized above a region of complex evaporites evacuation at depth, and likewise proximal to a shallower region characterized by high amplitude reflectors. The latter may be evidences for a shallow gas system. Our initial hypothesis proposes a dual shallow-source driven focused fluid flow system. Yet, we favour a deeper Messinian plumbing system driving fluid flow across the overburden in the study area. Corroborating this are fault systems characterized near the pipes feeding the seafloor pockmarks and paleo-pockmark, detaching in the upper Messinian evaporite. We further suggest that a combined supra-salt deformation system arising from the evacuation of the Messinian evaporites coupled with gravitational tectonics are in charge of modulating focused fluid flow. Under this scenario the emplaced mass transport complex acts as a transient reservoir for fluid flow, dewatering under deformation and channelling fluids towards the seafloor for expulsion. However, the contributions from microbially-generated methane in the shallow Quaternary overburden associated with the channel-levee complex cannot be neglected.

  12. Geologic appraisal of the petroleum potential of offshore southern California; the borderland compared to onshore coastal basins

    USGS Publications Warehouse

    Taylor, James Carlton

    1976-01-01

    Offshore southern California is part of a much larger Pacific continental margin, and the two areas have a similar geologic history at least as far back as middle Tertiary time. Assessment of the petroleum potential of the offshore Southern California borderland is accomplished by examining the adjacent highly explored productive coastal basins in the tectonically unstable area west of the San Andreas fault. Known oil and gas accumulations in this region can be characterized as follows: 88 percent comes from the Los Angeles and Ventura basins; 87 percent has been found in late Miocene and younger strata and only 0.2 percent has been found in Eocene strata; 80 percent has been found in thick deposits of deep-water turbidite reservoirs; and 5 percent has been found in fractured Miocene siliceous shale reservoirs. The percentage of siliceous shale reservoirs will increase as a result of recent discoveries in this rock type in the Santa Barbara Channel. Of the 212 known fields only 5 are giants (greater than 500 million barrels), and these fields account for 52 percent of all past production from the region. Most fields are faulted anticlines, and the largest fields have the highest oil recoveries per acre. Geologic knowledge of the offshore is limited by the availability of data. Data have been obtained from geophysical surveys, analyses of bedrock samples from the sea floor, and extrapolations of data from the mainland and offshore islands. Several factors have a negative effect on the assessment of the petroleum potential of the southern California borderland. They are: 1. The Neogene section is relatively thin, and the Paleogene section is thin and has a limited distribution. 2. Over large areas, Miocene sediments apparently rest directly on basement. 3. Along much of the Santa Rosa-Cortes Ridge, sediments are uplifted and truncated, exposing Paleogene rocks. 4. Organic content in Paleogene sediments is believed too low to generate large amounts of petroleum. 5

  13. Episodic Deep Fluid Expulsion at Mud Volcanoes in the Kumano Forearc Basin, SE Offshore Japan

    NASA Astrophysics Data System (ADS)

    Hammerschmidt, S.; Kopf, A.

    2014-12-01

    Compressional forces at convergent margins govern a variety of processes, most prominently earthquakes, landslides and mud volcanoes in the forearc. Although all seem related to fluid pressure changes, mud volcanoes are not only characterized by expulsion of fluids, but also fluidized mud and clasts that got ripped-up during mud ascension. They hence provide information regarding mobilization depth, diagenetic overprint, and geodynamic pathways. At the Nankai Trough subduction zone, SE offshore Japan, mud volcanism id common and supposed to be related to seismogenic processes. During MARUM Expedition SO-222 with R/V SONNE, mud volcanoes in the Kumano forearc basin were mapped, cored and sampled. By extending the Integrated Ocean Drilling Program (IODP) Kumano transect landwards, 5 new mud volcanoes were identified by multibeam mapping. Cores revealed mud breccia with semi-consolidated silt- to claystone clasts and gaseous fluid escape structures, while the hemipelagic background sediments are characterized by intercalations of turbidites, ash layers and calcareous fossils. Clasts were subject to thin-section analyses, and the cores were sampled for XRD analyses and radiocarbon dating. Clasts showed prominent deformation structures, neomorphism and pores and fractures filled with polycrystalline quartz and/or calcite cement, probably formed during deep burial and early metamorphosis. Illite crystallinity based on XRD measurements varies between 0.24 and 0.38, which implies that the material originates from the Anchizone at depths ≥ 4 km. Radiocarbon dating revealed ages between 4450 and 30300 yr cal. BP, with age reversals occurring not earlier than 17000 yr cal. BP. Radiocarbon dating beneath turbidites and ash layers found at mud volcano #9 points to an episodic occurrence of these earthquake-related features in intervals of ca. 620 yr, while the mud volcano itself remained inactive. In summary, the preliminary results suggest that the mud volcanoes are nurtured

  14. Can Khan Move the Bell Curve to the Right?

    ERIC Educational Resources Information Center

    Kronholz, June

    2012-01-01

    This article features Khan Academy which offers an online math program and short video lectures embedded in the "module", or math concept, that fit students' goals. By now, more than 1 million people have watched the online video in which Salman Khan--a charming MIT math whiz, Harvard Business School graduate, and former Boston hedge-fund…

  15. Schools "Flip" for Lesson Model Promoted by Khan Academy

    ERIC Educational Resources Information Center

    Sparks, Sarah D.

    2011-01-01

    The author reports on a "flip model" of instruction that has gotten national media attention lately, thanks to its promotion by Khan Academy, the high-profile nonprofit online-tutoring library created by Salman A. Khan, a Massachusetts Institute of Technology graduate who was looking for a way to help his young relatives with their homework. The…

  16. Can Khan Move the Bell Curve to the Right?

    ERIC Educational Resources Information Center

    Kronholz, June

    2012-01-01

    More than 1 million people have watched the online video in which Salman Khan--a charming MIT math whiz, Harvard Business School graduate, and former Boston hedge-fund analyst--explains how he began tutoring his cousins in math by posting short lessons for them on YouTube. Other people began watching the lessons and sending Khan adulatory notes.…

  17. Structure of the la VELA Offshore Basin, Western Venezuela: AN Obliquely-Opening Rift Basin Within the South America-Caribbean Strike-Slip Plate Boundary

    NASA Astrophysics Data System (ADS)

    Blanco, J. M.; Mann, P.

    2015-12-01

    Bathymetric, gravity and magnetic maps show that the east-west trend of the Cretaceous Great Arc of the Caribbean in the Leeward Antilles islands is transected by an en echelon series of obliquely-sheared rift basins that show right-lateral offsets ranging from 20 to 40 km. The basins are 75-100 km in length and 20-30 km in width and are composed of sub-parallel, oblique slip normal faults that define deep, bathymetric channels that bound the larger islands of the Leeward Antilles including Aruba, Curacao and Bonaire. A single basin of similar orientation and structure, the Urumaco basin, is present to the southwest in the Gulf of Venezuela. We mapped structures and sedimentation in the La Vela rift basin using a 3D seismic data volume recorded down to 6 seconds TWT. The basin can be mapped from the Falcon coast where it is correlative with the right-lateral Adicora fault mapped onshore, and its submarine extension. To the southeast of the 3D survey area, previous workers have mapped a 70-km-wide zone of northeast-striking, oblique, right-lateral faults, some with apparent right-lateral offsets of the coastline. On seismic data, the faults vary in dip from 45 to 60 degrees and exhibit maximum vertical offsets of 600 m. The La Vela and other obliquely-opening rifts accommodate right-lateral shear with linkages to intervening, east-west-striking right-lateral faults like the Adicora. The zone of oblique rifts is restricted to the trend of the Great Arc of the Caribbean and may reflect the susceptiblity of this granitic basement to active shearing. The age of onset for the basins known from previous studies on the Leeward Antilles is early Miocene. As most of these faults occur offshore their potential to generate damaging earthquakes in the densely populated Leeward Antilles is not known.

  18. Basin development and structure of the area covered by Tertiary basalts, offshore central West Greenland - implications of subvolcanic plays

    SciTech Connect

    Whittaker, R.C.; Bate, K.J.; Chalmers, J.A.

    1996-12-31

    The West Greenland shelf area between 68{degrees} and 72{degrees} is covered by Lower Tertiary basalts and has so far proved difficult to explore seismically compared to the offshore basins farther north (Melville Bay) and south (southern West Greenland). A first seismic and geological interpretation of the basalt area has lead to a better understanding of the tectonic events during the Tertiary and their implications for hydrocarbon exploration. After a period of extension accompanied by basalt volcanic in the Paleocene, a period of transpression occurred related to sea-floor spreading in the Labrador Sea and Baffin Bay. The crests of the anticlines formed were then eroded and transgressive marine sediments infilled the irregular topography and formed a number of restricted basins. Strike-slip faulting continued throughout the Eocene. Ongoing geophysical studies, including acquisition of additional seismic data in 1995, are aimed at improving seismic resolution beneath the basalts and deter- mining the structure and nature of the underlying sedimentary section. It has been possible, locally, to interpret horizons beneath the Paleocene volcanics where a thick sedimentary section is inferred to be present. The geological development of this succession has to be extrapolated from offshore southern West Greenland and the nearby onshore Nuussuaq basin. Active exploration including drilling started in the onshore basin in 1995 after the discovery of hydrocarbons in basalts at the surface and in shallow wells. The most promising play concept is subbasaltic reservoir sandstones with a mid- Cretaceous marine or a Paleocene deltaic oil-prone source rock. A possible post - basaltic play has also been identified and several large structural leads have been identified by mapping the Top Paleocene Volcanics horizon.

  19. Basin development and structure of the area covered by Tertiary basalts, offshore central West Greenland - implications of subvolcanic plays

    SciTech Connect

    Whittaker, R.C.; Bate, K.J.; Chalmers, J.A. )

    1996-01-01

    The West Greenland shelf area between 68[degrees] and 72[degrees] is covered by Lower Tertiary basalts and has so far proved difficult to explore seismically compared to the offshore basins farther north (Melville Bay) and south (southern West Greenland). A first seismic and geological interpretation of the basalt area has lead to a better understanding of the tectonic events during the Tertiary and their implications for hydrocarbon exploration. After a period of extension accompanied by basalt volcanic in the Paleocene, a period of transpression occurred related to sea-floor spreading in the Labrador Sea and Baffin Bay. The crests of the anticlines formed were then eroded and transgressive marine sediments infilled the irregular topography and formed a number of restricted basins. Strike-slip faulting continued throughout the Eocene. Ongoing geophysical studies, including acquisition of additional seismic data in 1995, are aimed at improving seismic resolution beneath the basalts and deter- mining the structure and nature of the underlying sedimentary section. It has been possible, locally, to interpret horizons beneath the Paleocene volcanics where a thick sedimentary section is inferred to be present. The geological development of this succession has to be extrapolated from offshore southern West Greenland and the nearby onshore Nuussuaq basin. Active exploration including drilling started in the onshore basin in 1995 after the discovery of hydrocarbons in basalts at the surface and in shallow wells. The most promising play concept is subbasaltic reservoir sandstones with a mid- Cretaceous marine or a Paleocene deltaic oil-prone source rock. A possible post - basaltic play has also been identified and several large structural leads have been identified by mapping the Top Paleocene Volcanics horizon.

  20. Seismic expression of depositional systems tracts and application to hydrocarbon exploration in Bredasdorp basin, offshore South Africa

    SciTech Connect

    Beamish, G.W.J.

    1989-03-01

    Postrift Cretaceous sequences of Bredasdorp basin, offshore South Africa, were rigorously analyzed using the unified application of the latest seismic-stratigraphic, sequence-stratigraphic, and depositional systems concepts. Using 101 seismic profiles totaling 5600 km, the authors identified ten cyclic depositional sequences bounded by nine type 1 and two type 2 unconformities. Component depositional systems tracts exhibit a distinct seismic expression and can be delineated using truncation and lap-out relationships. Lowstand systems tracts developed on type 1 unconformities, which resulted from relative sea level fall below the shelf edge. In a terrigenous clastic basin such as Bredasdorp, these tracts are interpreted as being composed of basin-floor turbidite fans, channels, and/or sheets. These features formed contemporaneously with the erosion of incised valleys and submarine canyons, followed by channelized slope fans and deltaic/coastal lowstand wedges that prograded during a relative sea level rise. Subsequent flooding of the shelf as relative sea level rise accelerated resulted in poorly defined transgressive systems tracts. With the relative sea level at a highstand, extensively developed deltaic/coastal systems prograded basinward exhibiting well-defined clinoforms. The major hydrocarbon plays in the lowstand tracts occur as mounded basin-floor turbidite fans, channel fills, and draped sheets and are found in the updip pinch-out of deltaic/coastal sandstones.

  1. Chapter 44: Geology and petroleum potential of the Lincoln Sea Basin, offshore North Greenland

    USGS Publications Warehouse

    Sorensen, K.; Gautier, D.; Pitman, J.; Ruth, Jackson H.; Dahl-Jensen, T.

    2011-01-01

    A seismic refraction line crossing the Lincoln Sea was acquired in 2006. It proves the existence of a deep sedimentary basin underlying the Lincoln Sea. This basin appears to be comparable in width and depth to the Sverdrup Basin of the Canadian Arctic Islands. The stratigraphy of the Lincoln Sea Basin is modelled in analogy to the Sverdrup Basin and the Central Spitsbergen Basin, two basins between which the Lincoln Sea intervened before the onset of seafloor spreading in the Eurasian Basin. The refraction data indicates that the Lincoln Sea Basin is capped by a kilometre-thick, low-velocity layer, which is taken to indicate an uplift history similar to, or even more favourable than, the fairway part of the Sverdrup Basin. Tectonic activity in the Palaeogene is likely to constitute the major basin scale risk. We conclude that the Lincoln Sea Basin is likely to be petroliferous and contains risked resources on the order of 1 ?? 109 barrels of oil, to which comes an equivalent amount of (associated and nonassociated) gas. ?? 2011 The Geological Society of London.

  2. Nearshore half-grabens as analogues for offshore, early Carboniferous rift basins along the SW Barents Sea Margin

    NASA Astrophysics Data System (ADS)

    Koehl, Jean-Baptiste; Bergh, Steffen G.; Indrevær, Kjetil; Lea, Halldis; Bergø, Espen; Henningsen, Tormod; Forthun, Tore; Faleide, Jan-Inge

    2016-04-01

    The present study focuses on the onshore-offshore correlation of brittle faults along the SW Barents Sea Margin, northern Norway. Several studies indicate that the SW Barents Sea Margin experienced a pulse of extensional deformation in the Late Devonian?-early Carboniferous, shortly after the Caledonian contractional deformation ended. The formation of major brittle faults and associated offshore basins that represent targets for hydrocarbon exploration, such as the NE-SW trending Nordkapp Basin, are thought to have initiated during this rifting event. Half-graben structures similar in shape and orientation to the southern segment of the Nordkapp Basin have been identified on the Finnmark Platform and in nearshore areas in coastal Finnmark, northern Norway. Although relatively smaller, these half-graben structures display the same asymmetric, sigma-shaped to triangular architecture in map view as the Nordkapp Basin and also initiated in the earliest Carboniferous, as confirmed by fossiliferous assemblages from shallow cores. The triangular shape of these half-graben structures is related to the presence of possible fault segments of the Trollfjord-Komagelv Fault Zone that trend WNW-ESE and partly truncate the NE-SW trending, sometimes arcuate, extensional brittle faults that bound the half-graben structures. High-resolution bathymetry data show that these half-graben structures internally display minor, NE-SW trending brittle faults and relatively high seafloor relief, thus possible fault displacement, at the intersection between these minor faults and the major, arcuate bounding faults. Microstructural analysis of fault-rocks in nearby onshore fault zones showed multiple generations of cataclasite, suggesting several episodes of faulting in the region. A major goal for future work will be to constrain the exact timing of the faulting event(s) with K/Ar radiometric dating of onshore fault-rocks. This may help estimating the timing of potential fluid migration

  3. A new frontier province offshore northwest Greenland: Structure, basin development, and petroleum potential of the Melville Bay area

    SciTech Connect

    Whittaker, R.C.; Hamann, N.E.

    1997-06-01

    In the Melville Bay area, offshore northwest Greenland, very large structures and sedimentary basins, which were predicted many years ago on the basis of magnetic and gravity data, have been confirmed by a recent reconnaissance seismic survey, with implications that are encouraging for petroleum exploration in the area. The Melville Bay area flanks a small ocean basin in Baffin Bay that is thought to have formed by oblique sea-floor spreading in the Eocene. There are two major, coast-parallel basins in the area. The inner basin, the Melville Bay Graben, is essentially a half graben with a maximum thickness of sediments exceeding 13 km. A complex fault-controlled ridge system separates this basin from the outer Kivioq Basin in which up to 7 km of sediments have accumulated. By analogy with onshore geology in the surrounding areas and well data from the continental shelves off southern west Greenland and Labrador to the south, it is expected that the first phase of rifting and sedimentation took place in the Early-middle Cretaceous, while a second phase of rifting took place in the latest Cretaceous and early Paleocene. Later, compression and inversion affected the northern part of the area, leading to the formation of large anticlinal structures. The existence of large tilted fault blocks and inversion anticlines provides grounds for anticipating the presence of large structural traps. Synrift sandstones and deeper water fans are expected to provide potential reservoirs, and correlatives of oil-prone source rocks known from the lower part of the upper Cenomanian-lower Maastrichtian Kanguk Formation in the Canadian Arctic may also have oil source properties in the Melville Bay area. Recent discoveries of live oil in the uppermost Cretaceous and lower Tertiary of onshore central west Greenland provide proof that oil has been generated in the region.

  4. Impact of Cenozoic strike-slip tectonics on the evolution of the northern Levant Basin (offshore Lebanon)

    NASA Astrophysics Data System (ADS)

    Ghalayini, Ramadan; Daniel, Jean-Marc; Homberg, Catherine; Nader, Fadi H.; Comstock, John E.

    2014-11-01

    Sedimentary basins adjacent to plate boundaries contain key tectonic and stratigraphic elements to understand how stress is transmitted through plates. The Levant Basin is a place of choice to study such elements because it flanks the Levant Fracture System and the Africa/Anatolia boundary. This paper uses new high-quality 3-D seismic reflection data to unravel the tectonic evolution of the margin of this basin during the Cenozoic, the period corresponding to the formation of the Levant Fracture System, part of the Africa/Arabia plate boundary. Four major groups of structures are identified in the interpreted Cenozoic units: NW-SE striking normal faults, NNE-SSW striking thrust-faults, ENE-WSW striking dextral strike-slip faults, and NNE trending anticlines. We demonstrate that all structures, apart of the NW-SE striking normal faults, are inherited from Mesozoic faults. Their reactivation and associated folding started during the late Miocene prior to the Messinian salinity crisis due to a NW-SE compressional stress field. No clear evidence of shortening at present-day offshore Lebanon and no large NNE-SSW strike-slip faults parallel to the restraining bend are found indicating that the Levant Fracture System is mainly contained onshore at present day. The intermittent activity of the interpreted structures correlates with the two stages of Levant Fracture System movement during late Miocene and Pliocene. This paper provides a good example of the impact of the evolution of plate boundaries on adjacent basins and indicates that any changes in the stress field, as controlled by the plate boundary, will affect immediately the preexisting structures in adjacent basins.

  5. 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)

    Gomez-Cabrera, Pedro Tomas

    2003-10-01

    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

  6. Pore size controls on the base of the methane hydrate stability zone in the Kumano Basin, offshore Japan

    NASA Astrophysics Data System (ADS)

    Daigle, Hugh; Dugan, Brandon

    2014-11-01

    The base of the methane hydrate stability zone (MHSZ) in the Kumano Basin, offshore Japan, is marked by a bottom-simulating reflection (BSR) on seismic data. At Integrated Ocean Drilling Program Site C0002, which penetrates this BSR, the in situ temperature profile combined with bulk seawater methane equilibrium conditions suggest that the base of the MHSZ is 428 m below seafloor (bsf), which is 28 m deeper than the observed BSR (400 m bsf). We found that submicron pore sizes determined by mercury injection capillary pressure are sufficiently small to cause 64% of the observed uplift of the base of the MHSZ by the Gibbs-Thomson effect. This is the most thorough characterization of pore sizes within the MHSZ performed to date and illustrates the extent to which pore size can influence MHSZ thickness. Our results demonstrate the importance of considering lithology and pore structure when assessing methane hydrate stability conditions in marine sediments.

  7. Infrared inspection applied to offshore platforms: Petrobras experience at Campos Basin

    NASA Astrophysics Data System (ADS)

    Verdini, Edson A.; Veratti, Attilio B.

    2002-03-01

    Bacia de Campos (Rio de Janeiro - Brazil) is one of the biggest offshore petroleum fields in the world today. In June 2001, Bacia de Campos, having more than 490 oil wells, 34 offshore platforms and 7 modified ships in operation, reached 1,3 million barrels/day. If compared to OPEP countries only nine of them got an average production higher than 1 million barrels/day in 2000, which means it can be placed on the 10th position in the rank of oil producers. In this context this work aims not only to show the results achieved within the introduction of thermographic inspections in offshore oil production (platforms and ships), but also the financial results (ROI - Return of Investment) considering the use of this particular technique. Bacia de Campos got a ROI around 7 million dollars in the last 4 years, which means a hundred times higher than the total cost of thermographic services in the same period. As far as we know this is one of the best results already reported in the world. We also present the methodology applied to analyze thermal anomalies in electrical components and data management software, including advanced Digital Reports sent via Internet.

  8. Manufacturing and design of the offshore structure Froude scale model related to basin restrictions

    NASA Astrophysics Data System (ADS)

    Scurtu, I. C.

    2015-11-01

    Manufacturing steps for a modern three - column semi-submersible structure are delivered using CFD/CAE software and actual Froude scaled model testing. The three- column offshore is part of the Wind Float Project already realized as prototype for wind energy extraction in water depths more than 40 meters, and the actual model will not consider the wind turbine. The model will have heave plates for a smaller heave motion in order to compare it with the case without heave plates. The heave plates will be part of the Froude scale model.. Using a smaller model will determine a smaller heave motion and this will affect predictions of the vertical movement of the three- column offshore structure in real sea. The Froude criterion is used for the time, speed and acceleration scale. The scale model is manufactured from steel and fiberglass and all parts are subjected to software analysis in order to get the smallest stress in connections inside the model. The model mass was restricted by scale dimensions and also the vertical position of centre gravity will be considered during the manufacturing and design process of the Froude scale offshore structure. All conditions must converge in model manufacturing and design in order to get the best results to compare with real sea states and heave motion data.

  9. Khan Academy: the world's free virtual school

    NASA Astrophysics Data System (ADS)

    Dijksman, Joshua A.; Khan, Salman

    2011-03-01

    Khan Academy offers an unprecedented set of educational material for science and math education, in the form of short, free, publicly available video clips. With a growing set of already over 2000 videos, it is easily the most exhaustive collection of structured educational material on the Internet. The content is made in digestible 10-20 minute chunks; the granular nature of the material allows learners to fill in almost any of their knowledge ``gaps.'' Importantly, the conversational style used in the videos offers a fresh, new perspective on math and science instruction. With our 2 M funding grant from Google and support from the Gates foundation, we envision covering all topics that would appear in typical high-school or collegiate-level Math and Science courses, and translating these videos to the major languages across the globe. Moreover, we also offer a free and fully integrated assessment system, which allows students to practice problems at their own pace and focus on the appropriate instruction to fill in their individual gaps. Many testimonials have already proven our methods to be a highly successful educational tool. Our goal is to allow educators to improve their teaching, but above all to bring simple, rewarding and enjoyable education to the minds of many young students. Supported by Google, the Gates Foundation, donors and volunteers.

  10. Evaluation and detection of overpressures in a Deltaic Basin: The Sisi Field case history, offshore Mahakam, Kutei Basin, Indonesia

    SciTech Connect

    Grosjean, Y. ); Bois, M.; De Pazzis, L. ); Burrus, J. )

    1994-07-01

    Widespread overpressure occurrences in the Mahakama delta area have caused a number of kicks and several blow-outs during earlier exploration. A review of pore pressure indications was conducted in conjunction with an extensive reinterpretation of seismic and well data basin wide. The iso-pressure lines were found to be broadly parallel to the facies change from sandy, delta-front deposits to outer shelf and slope shales, and are not associated with organic matter maturation or clay diagenesis. Overpressures are reached at depths ranging from 1000 m to more than 4000 m, depending on the facies. A 2-D numerical basin model calibrated on observed pressure profiles at wells indicated that the excess pressures were a direct function of the variable drainage efficiency of the formations by interbedded sands. The Sisi discovery located at the eastern, distal extremity of the upper Miocene deltaic sands provided a unique opportunity for a more detailed analysis. A hypothesis of widespread decoupling between reservoir and shale pore pressures was tested against well data during appraisal drilling. D-exponent plots and gas shows were carefully monitored to assess the excess pressures, and quantitative estimates of the shale pore pressures were computed from sonic logs. A regionally consistent calibration was achieved, which confirmed very large discrepancies compared to the pressures measured in interbedded permeable reservoirs. These conclusions have since been generalized to other areas of the basin, where they allowed safer drilling practices to be established as demonstrated by the observed reduction of lost time.

  11. Talang Akar-Cibulakan( ) petroleum systems, Arjuna Basin, offshore Northeast Java, Indonesia

    SciTech Connect

    Chandra, S.; Gresko, M.J. ); Sinclair, S.W. )

    1996-01-01

    The Talang Akar-Cibulakan( ) petroleum systems occur in the Arjuna basin, one of a series of basins on the southern edge of the Sunda craton originating during a major Eocene-Oligocene period of extension. Total in-place hydrocarbons of 2.5 BBO and 3 TCFG have been discovered since 1968. Over 1000 wells have been drilled, and 1 BBO and 1.1-TCFG have been produced from 70 fields. Major reservoirs are Upper Oligocene to Lower Miocene fluvial sandstones of the Talang Aker Formation and Middle to Upper Miocene shallow-marine sandstones of the Cibulakan Formation. Geochemical analyses indicate that Talang Aker coals and shales are the principal source of hydrocarbons in this prolific petroleum systems. This source interval has thicknesses from <125 m on flanks and highs to > 600 m in the axis of the basin. These source rocks contain main; terrestrially-derived organic mater but source quality varies considerably. Carbonaceous shales are mainly gas prone while liptinite-enriched coals are good oil and gas source rocks. Geohistory modelling indicates that hydrocarbon generation was initiated by Middle Miocene (15 mya) and reached its peak at Upper Miocene (10 mya). Primary migration at Middle Miocene resulted in hydrocarbon charge of interbedded reservoir rocks. Secondary migration since post-Upper Miocene, concurrent with renewed tectonism, has been mainly vertical through fault-related fractures. Basin-wide source rock and hydrocarbon characteristics, in combination with structural and stratigraphic framework, define these supercharged and vertically drained petroleum systems.

  12. Talang Akar-Cibulakan(!) petroleum systems, Arjuna Basin, offshore Northeast Java, Indonesia

    SciTech Connect

    Chandra, S.; Gresko, M.J.; Sinclair, S.W.

    1996-12-31

    The Talang Akar-Cibulakan(!) petroleum systems occur in the Arjuna basin, one of a series of basins on the southern edge of the Sunda craton originating during a major Eocene-Oligocene period of extension. Total in-place hydrocarbons of 2.5 BBO and 3 TCFG have been discovered since 1968. Over 1000 wells have been drilled, and 1 BBO and 1.1-TCFG have been produced from 70 fields. Major reservoirs are Upper Oligocene to Lower Miocene fluvial sandstones of the Talang Aker Formation and Middle to Upper Miocene shallow-marine sandstones of the Cibulakan Formation. Geochemical analyses indicate that Talang Aker coals and shales are the principal source of hydrocarbons in this prolific petroleum systems. This source interval has thicknesses from <125 m on flanks and highs to > 600 m in the axis of the basin. These source rocks contain main; terrestrially-derived organic mater but source quality varies considerably. Carbonaceous shales are mainly gas prone while liptinite-enriched coals are good oil and gas source rocks. Geohistory modelling indicates that hydrocarbon generation was initiated by Middle Miocene (15 mya) and reached its peak at Upper Miocene (10 mya). Primary migration at Middle Miocene resulted in hydrocarbon charge of interbedded reservoir rocks. Secondary migration since post-Upper Miocene, concurrent with renewed tectonism, has been mainly vertical through fault-related fractures. Basin-wide source rock and hydrocarbon characteristics, in combination with structural and stratigraphic framework, define these supercharged and vertically drained petroleum systems.

  13. The heat flow study in the Tertiary Basin of Vietnam offshore

    SciTech Connect

    Huyen, T.

    1994-07-01

    In Vietnam, study of heat flow has paralleled petroleum exploration activities. For a long time there had only been results on temperature gradients in the Tertiary basin. Recently, with its participation in CCOP's project on the establishment of heat flow regional maps (1992-1993) and the government's mineral resources program (1993-1995) (Coded KT-01-18), Vietnam Petroleum Institute's group on heat flow obtained results on heat flow. A heat flow study in the oil basinal area in Vietnam has been conducted using data from 76 exploratory wells. Thermal conductivity of 427 cores was measured using the quick thermal conductivity meter (QTM) within temperature gradients of wells calculated from well log data and from testing data. The average heat flow of sedimentary basins in Vietnam follows: Hanoi graben, 125 Q (mW/m2); north Gulf of Tonkin, 87 Q (mW/m2); south Gulf of Tonkin, 119 Q (mW/m2); Danang Graben, 89 Q (mW/m2); northeast-south Conson, 88 Q (mW/m2); southwest-south Conson, 85 Q (mW/m2); Mekong Basin, 64 Q (mW/m2).

  14. A three-step model to assess shoreline and offshore susceptibility to oil spills: the South Aegean (Crete) as an analogue for confined marine basins.

    PubMed

    Alves, Tiago M; Kokinou, Eleni; Zodiatis, George

    2014-09-15

    This study combines bathymetric, geomorphological, geological data and oil spill predictions to model the impact of oil spills in two accident scenarios from offshore Crete, Eastern Mediterranean. The aim is to present a new three-step method of use by emergency teams and local authorities in the assessment of shoreline and offshore susceptibility to oil spills. The three-step method comprises: (1) real-time analyses of bathymetric, geomorphological, geological and oceanographic data; (2) oil dispersion simulations under known wind and sea current conditions; and (3) the compilation of final hazard maps based on information from (1) and (2) and on shoreline susceptibility data. The results in this paper show that zones of high to very-high susceptibility around the island of Crete are related to: (a) offshore bathymetric features, including the presence of offshore scarps and seamounts; (b) shoreline geology, and (c) the presence near the shore of sedimentary basins filled with unconsolidated deposits of high permeability. Oil spills, under particular weather and oceanographic conditions, may quickly spread and reach the shoreline 5-96 h after the initial accident. As a corollary of this work, we present the South Aegean region around Crete as a valid case-study for confined marine basins, narrow seaways, or interior seas around island groups. PMID:25113103

  15. The Structure and Evolution of the Sabratah Basin, West Offshore Libya.

    NASA Astrophysics Data System (ADS)

    Reeh, G. A.; Reston, T. J.

    2014-12-01

    The Sabratah Basin is situated on the continental margin of Africa. In this presentation we use a series of grids of 3D seismic data, supported by potential field data, to document the structure and evolution of the basin. Although the basin is thought to be underlain by Paleozoic rocks, the oldest encountered in wells are Triassic in age. These are continental passing upwards into evaporites, a sequence thought to represent the progressive subsidence of the margin during major Mesozoic extension related to the opening of the Tethyan Ocean. Continued subsidence through the Jurassic and Early Cretaceous led to the deposition of marine sequences. The basin deepens towards the northeast, as the crust thins in the same direction. Crustal thinning in this direction is supported by an increase from southwest to northeast in the gravity. However, since the Late Cretaceous, there has been compression between Africa and Europe as a result of the Alpine collision, causing the inversion of the former extensional features, and creating en echelon folds trending ENE-WSW and segmented by en echelon northwest trending right-lateral faults. The geometries we observe are consistent with a right lateral shear roughly parallel to the continental margin. The Bouguer gravity anomaly map of the Sabratah Basin has relatively a smooth gradient with gravity increasing seaward to the northeast. The strong southwest-to-northeast increase in gravity values is probably related to the seaward swallowing of Moho as the crust thins in the that direction. This gradient is interrupted by two local gravity anomalies associated with magnetic anomalies and bounded the Sabratah basin, the WNW trending Jarrafa anomaly to the NE and to the SW the NS trending Jeffara anomaly with varying amplitudes. The high density and magnetisation of the source bodies indicates that they probably comprise mafic igneous rock. The depth to magnetic source estimated by source parameter imaging (SPI) and Euler

  16. 2D numerical modeling of gravity-driven giant-scale deformation processes in the offshore Barreirinhas Basin (Brazil)

    NASA Astrophysics Data System (ADS)

    Cruciani, Francesco; Manconi, Andrea; Rinaldo Barchi, Massimiliano

    2014-05-01

    Gravity-driven deformation processes at continental passive margins occur at different scales, from small-scale turbidity currents and sediment slides, to large-scale mass transport complexes (MTCs), to the giant-scale deep water fold and thrust belts (DW-FTBs), which affect most or the entire sedimentary sequence. This kind of giant structures, quite widespread in passive margins, may be active for tens of millions of years. In this context, the Brazilian Atlantic margin hosts several well-known DW-FTBs detached on both shale and salt décollement. Despite of their relevant scientific and economic importance, the mechanical processes driving the onset and evolution of these giant-scale structures are still poorly investigated. In this work, we focus on the shale décollement DW-FTB of the Barreirinhas Basin, where the continental slope has been affected by multi-phase gravitational processes since the Late Cretaceous. This DW-FTB consists of a linked fault system of listric normal faults updip and thrust faults downdip, detached over a common concave upward décollement surface. From the onshore extensional to the offshore compressional domain the DW-FTB is about 50 km wide and involve a sedimentary sequence up to 5 km thick. Shortening within the compressional domain is accommodated almost entirely from a single thrust ramp with a large related anticline fold. Previous studies have shown that the main activity phases of the gravitational processes are closely linked to significant increases in the sediment supply within the basin. Indeed, the highest deformation rate, accounting for about 80% of the net strain, occurred in the Upper Miocene following a drainage rearrangement which led to the birth of the modern Amazon River drainage system. The Barreirinhas Basin DW-FTB entails a rather simple geometrical structure, which can be well schematized, therefore is particularly suitable for numerical simulations aimed to study and understand the dynamics of DW-FTB at

  17. Metals in water, sediments, and biota of an offshore oil exploration area in the Potiguar Basin, Northeastern Brazil.

    PubMed

    Lacerda, L D; Campos, R C; Santelli, R E

    2013-05-01

    Metal concentrations were evaluated in water, bottom sediments, and biota in four field campaigns from 2002 to 2004 in the Potiguar Basin, northeastern Brazil, where offshore oil exploration occurs. Analyses were performed by inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry. Total metal concentrations in water (dissolved + particulate) and sediments were in the range expected for coastal and oceanic areas. Abnormally high concentrations in waters were only found for Ba (80 μg l(-1)) and Mn (12 μg l(-1)) at the releasing point of one of the outfalls, and for the other metals, concentrations in water were found in stations closer to shore, suggesting continental inputs. In bottom sediments, only Fe and Mn showed abnormal concentrations closer to the effluent releasing point. Metal spatial distribution in shelf sediments showed the influence of the silt-clay fraction distribution, with deeper stations at the edge of the continental shelf, which are much richer in silt-clay fraction showing higher concentrations than shallower sediments typically dominated by carbonates. Metal concentrations in estuarine (mollusks and crustaceans) and marine (fish) organisms showed highest concentrations in oysters (Crassostrea rhizophorae). Fish tissues metal concentrations were similar between the continental shelf influenced by the oil exploration area and a control site. The results were within the range of concentrations reported for pristine environments without metals contamination. The global results suggest small, if any, alteration in metal concentrations due to the oil exploration activity in the Potiguar Basin. For monitoring purposes, the continental inputs and the distribution of the clay-silt fraction need to be taken into consideration for interpreting environmental monitoring results. PMID:23014923

  18. Rovearinids (stemless crinoids) in the Albian carbonates of the offshore Santos Basin, southeastern Brazil: stratigraphic, palaeobiogeographic and palaeoceanographic significance

    NASA Astrophysics Data System (ADS)

    Dias-Brito, D.; Ferré, B.

    2001-06-01

    Microfacies analysis of marine carbonates cored by Petrobras well 1-SPS-6 in the offshore Santos Basin (southeastern Brazil) has revealed a remarkable fossil assemblage of calpionellids (colomiellids), favusellids, hedbergellids, globigerinelloidids, buliminids, radiolarians, inoceramid prisms, roveacrinids, and saccocomids(?) preserved in lower Albian calcimudstones-wackestones of the lower part of the Guarujá Formation. This assemblage represents an allochtonous accumulation in a deep neritic to shallow bathyal hypoxic environment. Besides 'saccocomid-like' sections, the only determinable sections of roveacrinids are thecal plates of Poecilocrinus dispandus elongatus Peck, 1943. This species was previously only known from the Weno Formation of Texas. The Brazilian material extends its records farther south from at least the lower Albian, which then represents the earliest occurrence of this peculiar family in the South Atlantic region. Taking into account their Albian global distribution and the location of their oldest representative (Hauterivian near Alicante, Spain), the Roveacrinidae dispersed westward throughout all of Cretaceous Tethys. The Tethyan origin of Roveacrinidae is further evidence that, during late Aptian-Albian times, the northern South Atlantic (north of the Walvis-São Paulo Ridge) was supplied by a Tethyan water mass.

  19. The geostatistical approach for structural and stratigraphic framework analysis of offshore NW Bonaparte Basin, Australia

    NASA Astrophysics Data System (ADS)

    Wahid, Ali; Salim, Ahmed Mohamed Ahmed; Gaafar, Gamal Ragab; Yusoff, Wan Ismail Wan

    2016-02-01

    Geostatistics or statistical approach is based on the studies of temporal and spatial trend, which depend upon spatial relationships to model known information of variable(s) at unsampled locations. The statistical technique known as kriging was used for petrophycial and facies analysis, which help to assume spatial relationship to model the geological continuity between the known data and the unknown to produce a single best guess of the unknown. Kriging is also known as optimal interpolation technique, which facilitate to generate best linear unbiased estimation of each horizon. The idea is to construct a numerical model of the lithofacies and rock properties that honor available data and further integrate with interpreting seismic sections, techtonostratigraphy chart with sea level curve (short term) and regional tectonics of the study area to find the structural and stratigraphic growth history of the NW Bonaparte Basin. By using kriging technique the models were built which help to estimate different parameters like horizons, facies, and porosities in the study area. The variograms were used to determine for identification of spatial relationship between data which help to find the depositional history of the North West (NW) Bonaparte Basin.

  20. Identification, mapping, and analysis of possible evidences of active petroleum systems in the Colorado Basin, offshore Argentina, South America

    NASA Astrophysics Data System (ADS)

    Loegering, Markus; Anka, Zahie; Rodriguez, Jorge; Marchal, Denis; di Primio, Rolando; Vallejo, Eduardo; Kohler, Guillermina; Pangaro, Francisco

    2010-05-01

    The analysis of a dense 2D seismic reflection dataset and 12 exploration wells data, allowed us to reconstruct the geological evolution of the Colorado Basin, offshore Argentina. We identified and mapped the major syn- and post-rift seismic sequences, and their boundaries such as unconformities and regional seismic markers, present on the continental shelf and slope (water depths from 50 to 1800 m) of the Colorado Basin. Seismic-to-well log correlations, as well as integration with biostratigraphic data provided a chrono-stratigraphic framework for the interpreted horizons. The construction of isochronal (twt) maps provided a 3D spatial visualisation of the stratigraphic relationship among the sequences. The maps show a change in configuration from the break-up unconformity (130 Ma) to the present-day seafloor. The break-up unconformity displays a central EW-elongated graben which prevails on the overlying sequences up to the Miocene. The EW Colorado basin turns NW-SE towards the East, going perpendicular to the present-day continental margin (oriented NE-SW). The strong obliquity of the basin orientation related to the direction corresponding to the opening of the South Atlantic (NE-SW) suggests a structural control from the pre-rift basement on the rift and post-rift sequences. Starting from the break-up unconformity, the history of basin filling is illustrated up to the flat seafloor. The basin sag phase is represented by the sequences deposited between the break-up unconformity and the Colorado discontinuity (Aptian to Campanian). The Campanian to Eocene successions are more or less parallel- layered suggesting sequence aggradation. The distribution of liquid/gas hydrocarbon-leakage features (i.e. gas chimneys, mud volcanoes, and seabed pockmarks) should allow the definition of potential migration pathways. In this sense, a systematic mapping of these paleo- and present-day features observed in the seismic profiles has been performed and their distribution was

  1. Methane Hydrate Recovered From A Mud Volcano in Santa Monica Basin, Offshore Southern California

    NASA Astrophysics Data System (ADS)

    Normark, W. R.; Hein, J. R.; Powell, C. L.; Lorenson, T. D.; Lee, H. J.; Edwards, B. D.

    2003-12-01

    In July 2003, a short (2.1 m) piston core from the summit of a mud volcano recovered methane hydrate at a water depth of 813 m in Santa Monica Basin. The discovery core penetrated into in the hydrate as evidenced by chunks of ice and violent degassing of the core section between 162 and 212 cm depth. The core consists of shell hash and carbonate clasts (to 7-cm long) in silty mud. The methanogenic carbonates are of two types: massive, recrystallized nodular masses with an outer mm-thick sugary patina and a bivalve coquina with carbonate cement. Living clams including the genus Vesicomya, commonly found at cold-seep sites elsewhere, were recovered from the top of the core. Further sampling attempts using piston, gravity, and box corers, all of which were obtained within 15 m of the discovery core, recovered olive-brown silty mud with variable amounts of whole and fragmented bivalve shells and methanogenic carbonate fragments characteristic of cold-seep environments. Gases collected in cores adjacent to the discovery core contain elevated amounts of methane and trace amounts of heavier hydrocarbon gases, indicating some component from thermogenic sources. Hydrogen sulfide was also detected in these sediment samples. Vertical channels in one core may have served as fluid pathways. The existence of hydrate at such a shallow depth in the sediment was unexpected, however, the presence of Vesicomya and hydrogen sulfide indicate that the mud volcano is a site of active methane venting. The mud volcano, which is about 24 km west-southwest of Redondo Beach, is about 300 m in diameter at the base. No internal structure is resolved on either high resolution deep-tow boomer or single-channel air-gun profiles, most likely as a result of the gas content and sediment deformation. The diapiric structure has ascended through well-bedded sediment on the lower slope of the basin, producing as much as 30 m of bathymetric relief. It is located in an area where strike-slip motion along

  2. Comparison of offshore and onshore gas occurrences, Eel River basin, northern California

    USGS Publications Warehouse

    Lorenson, T.D.; McLaughlin, Robert J.; Kvenvolden, Keith A.; Orange, Daniel L.; Davisson, M. Lee; Brewer, Peter G.; Martin, J.B.

    1998-01-01

    The Eel River basin of northern California is a upper Cenozoic depocenter containing more than 3,000 meters of sedimentary rock located near the Mendocino triple junction. Active tectonism has resulted in folding, faulting and rapid sedimentation. Both thermogenic and microbial hydrocarbons are known to be present in the sediments. In August 1997, we sampled two submarine gas seeps, one at a water depth of 520 m that supports a chemosynthetic-based ecosystem very near an area of previously recovered gas hydrate. Another vent site was sampled in sand covered with white bacterial mats at a water depth 41 m. We compared the hydrocarbon gas composition and methane isotopic composition of these seeps with land-based gas occurrences that include: 1) a gas seep and 2) gas from a 2360 m-deep gas well.

  3. Seismic imaging of a fractured gas hydrate system in the Krishna-Godavari Basin offshore India

    USGS Publications Warehouse

    Riedel, M.; Collett, T.S.; Kumar, P.; Sathe, A.V.; Cook, A.

    2010-01-01

    Gas hydrate was discovered in the Krishna-Godavari (KG) Basin during the India National Gas Hydrate Program (NGHP) Expedition 1 at Site NGHP-01-10 within a fractured clay-dominated sedimentary system. Logging-while-drilling (LWD), coring, and wire-line logging confirmed gas hydrate dominantly in fractures at four borehole sites spanning a 500m transect. Three-dimensional (3D) seismic data were subsequently used to image the fractured system and explain the occurrence of gas hydrate associated with the fractures. A system of two fault-sets was identified, part of a typical passive margin tectonic setting. The LWD-derived fracture network at Hole NGHP-01-10A is to some extent seen in the seismic data and was mapped using seismic coherency attributes. The fractured system around Site NGHP-01-10 extends over a triangular-shaped area of ~2.5 km2 defined using seismic attributes of the seafloor reflection, as well as " seismic sweetness" at the base of the gas hydrate occurrence zone. The triangular shaped area is also showing a polygonal (nearly hexagonal) fault pattern, distinct from other more rectangular fault patterns observed in the study area. The occurrence of gas hydrate at Site NGHP-01-10 is the result of a specific combination of tectonic fault orientations and the abundance of free gas migration from a deeper gas source. The triangular-shaped area of enriched gas hydrate occurrence is bound by two faults acting as migration conduits. Additionally, the fault-associated sediment deformation provides a possible migration pathway for the free gas from the deeper gas source into the gas hydrate stability zone. It is proposed that there are additional locations in the KG Basin with possible gas hydrate accumulation of similar tectonic conditions, and one such location was identified from the 3D seismic data ~6 km NW of Site NGHP-01-10. ?? 2010.

  4. Commentary: The Khan Academy and the Day-Night Flipped Classroom

    ERIC Educational Resources Information Center

    Parslow, Graham R.

    2012-01-01

    Teaching by night and reflecting on a subject by day is the way that Salman Khan sees education evolving in the age of online lectures. Khan believes he is onto something in what he styles the "flipped classroom." In Khan's view, there is no need for students to be divided into grades by age. Instead, they should learn at their own pace, moving on…

  5. "Kubla Khan" and Its Narratives of Possible Worlds

    ERIC Educational Resources Information Center

    Nayar, Pramod K.

    2013-01-01

    This essay argues that Coleridge's "Kubla Khan" is a poem about narrative and specifically focuses on the narrative construction of possible worlds, or even utopian worlds. It notes two pairs of narratives. In pair one the utopian narrative of the monarch's decree which seeks to build a space of pure pleasure is in opposition to the…

  6. Documenting channel features associated with gas hydrates in the Krishna-Godavari Basin, offshore India

    USGS Publications Warehouse

    Riedel, M.; Collett, T.S.; Shankar, U.

    2011-01-01

    During the India National Gas Hydrate Program (NGHP) Expedition 01 in 2006 significant sand and gas hydrate were recovered at Site NGHP-01-15 within the Krishna-Godavari Basin, East Coast off India. At the drill site NGHP-01-15, a 5-8m thick interval was found that is characterized by higher sand content than anywhere else at the site and within the KG Basin. Gas hydrate concentrations were determined to be 20-40% of the pore volume using wire-line electrical resistivity data as well as core-derived pore-fluid freshening trends. The gas hydrate-bearing interval was linked to a prominent seismic reflection observed in the 3D seismic data. This reflection event, mapped for about 1km2 south of the drill site, is bound by a fault at its northern limit that may act as migration conduit for free gas to enter the gas hydrate stability zone (GHSZ) and subsequently charge the sand-rich layer. On 3D and additional regional 2D seismic data a prominent channel system was imaged mainly by using the seismic instantaneous amplitude attribute. The channel can be clearly identified by changes in the seismic character of the channel fill (sand-rich) and pronounced levees (less sand content than in the fill, but higher than in surrounding mud-dominated sediments). The entire channel sequence (channel fill and levees) has been subsequently covered and back-filled with a more mud-prone sediment sequence. Where the levees intersect the base of the GHSZ, their reflection strengths are significantly increased to 5- to 6-times the surrounding reflection amplitudes. Using the 3D seismic data these high-amplitude reflection edges where linked to the gas hydrate-bearing layer at Site NGHP-01-15. Further south along the channel the same reflection elements representing the levees do not show similarly large reflection amplitudes. However, the channel system is still characterized by several high-amplitude reflection events (a few hundred meters wide and up to ~1km in extent) interpreted as gas

  7. Ocean basin structure offshore the Southeastern United States: Is it the rift's fault?

    NASA Astrophysics Data System (ADS)

    Heffner, D. M.; Knapp, J. H.

    2012-12-01

    Continental rifts typically exhibit an asymmetrical geometry where major normal faults bound one side of a rotated block, and the rift basins thin toward the opposite hinge side. Differential extension on major faults is accommodated by transverse structures referred to as transfer zones, across which the asymmetric geometry may reverse polarity. It was proposed several decades ago that oceanic transforms between mid-ocean ridge spreading centers are inherited features of these rift-related transfer zones, and that these intra-plate structures are tectonically active. However, preserved evidence of onshore transfer zones is often lacking, particularly along the rifted margin of Eastern North America, and recent studies have suggested that oceanic transforms are not inherited structures. Observations of seismic reflection data integrated with well data show that adjacent basin bounding faults of the South Georgia Rift, a Triassic rift in the southeastern United States, occur on opposite sides of the rift flanks. The Walterboro and Warner Robins Transfer Zones identified in this study project along the small circles of Schettino and Turco (2009) into the Jacksonville and Bahamas Fracture Zones respectively. This projection is particularly interesting as it suggests the correlation of continental to oceanic features is one step south compared to previous studies which projected the Blake Spur Fracture Zone through the Charleston, SC region, and the Jacksonville Fracture Zone through Georgia. Using the same small circle solution, the Blake Spur Fracture Zone projects through the Blake Outer Ridge, a sedimentary drift which shows up prominently as a gravity anomaly the core of which has been identified as a tectonic feature reminiscent of a fracture zone on the basis of gravity modeling (Dove et al., 2007). Although no transfer zone has been identified where this small circle project onshore, it is approximately coincident with axis of the Cape Fear Arch which has been

  8. Acoustic reflections in the water column of Krishna-Godavari offshore basin, Bay of Bengal.

    PubMed

    Sinha, Satish K; Dewangan, Pawan; Sain, Kalachand

    2016-05-01

    Seismic oceanographic studies from various oceans worldwide have indicated that the acoustic reflections are mostly observed along thermal boundaries within the water column. However, the authors present a case study of seismic data from Krishna-Godavari Basin which shows that salinity variations also play an important role in the occurrence of water column reflections. The observed reflection is modeled using the reflectivity series derived from the salinity and temperature profiles from a nearby Conductivity-Temperature-Depth (CTD) location. Sensitivity analysis of temperature and salinity on soundspeed shows that the effect of salinity cannot be ignored for modeling acoustic reflections. The synthetic seismogram matches well with the observed reflection seismic data. Remarkable similarities between the reflection seismic and the salinity profile in the upper thermocline suggest the importance of salinity variations on the water column reflection. Furthermore, impedance inversion of the reflectivity data reveals several thermohaline structures in the water column. The origin of these thermohaline structures is largely unaddressed and may be attributed to the fresh water influx coming from Himalayan and Peninsular rivers or due to the presence of different water masses in the Indian Ocean which warrants a detailed study using concurrent seismic and CTD data. PMID:27250139

  9. Prospect evaluation of shallow I-35 reservoir of NE Malay Basin offshore, Terengganu, Malaysia

    NASA Astrophysics Data System (ADS)

    Janjua, Osama Akhtar; Wahid, Ali; Salim, Ahmed Mohamed Ahmed; Rahman, M. Nasir B. A.

    2016-02-01

    A potential accumulation of hydrocarbon that describes significant and conceivable drilling target is related to prospect. Possibility of success estimation, assuming discovery of hydrocarbons and the potential recoverable quantities range under a commercial development program are the basis of Prospect evaluation activities. The objective was to find the new shallow prospects in reservoir sandstone of I -Formation in Malay basin. The prospects in the study area are mostly consisting of faulted structures and stratigraphic channels. The methodology follows seismic interpretation and mapping, attribute analysis, evaluation of nearby well data i.e., based on well - log correlation. The petrophysical parameters analogue to nearby wells was used as an input parameter for volumetric assessment. Based on analysis of presence and effectiveness, the prospect has a complete petroleum system. Two wells have been proposed to be drilled near the major fault and stratigraphic channel in I-35 reservoir that is O-1 and O-2 prospects respectively. The probability of geological success of prospect O-1 is at 35% while for O-2 is 24%. Finally, for hydrocarbon in place volumes were calculated which concluded the best estimate volume for oil in O-1 prospect is 4.99 MMSTB and O-2 prospect is 28.70 MMSTB while for gas is 29.27 BSCF and 25.59 BSCF respectively.

  10. 3D Seismic Studies of Igneous Intrusions, Taranaki Basin, off-shore west New Zealand

    NASA Astrophysics Data System (ADS)

    Harbor, R. L.; Chrisitiansen, E. H.; Keach, R. W.

    2008-12-01

    Several off-shore volcano-plutonic complexes are imaged in a detailed 3D seismic survey acquired by Pogo New Zealand/Plains Exploration. The new data provide insight into the sizes, shapes, and wall rock deformation associated with the emplacement of plutons. The seismic survey, conducted in 2005, covers 1700 km2 and was processed with modern techniques used in hydrocarbon exploration. The images and structures have to be interpreted with care because of distortions caused by "velocity pull ups" created by the large seismic wave velocity contrast between sediment and igneous rock. The magmatic rocks may be part of the Mohakatino Volcanic Centre (15 to 1.5 Ma) that intrudes and partially fills the Taranaki graben, which began to form in the Cretaceous. Imaged plutons range from less than 1 to as much as 12 km across. The intrusions are steep-sided and do not resemble sills, but their bases are poorly resolved. The top of the largest complex is sharply delineated and marked by multiple apophyses as much as 2 km across and hundreds of meters high. Deformation along the sides of the intrusion is dominated by of a faulted rim anticline, with apparent dips of 45° or higher. Dips decrease rapidly away from the intrusion but doming extends several hundred meters from the margins. A series of high-angle faults fan out from the margin of the pluton and cut the folded strata along the margin. These faults terminate against the margins of the intrusion, extend as much as 1 pluton diameter away from the margin, and then merge with "regional" faults that are part of the Taranaki graben. Offset along these radiating faults is on the order of a few hundred meters. Strata on the top of the complex are thinned but are deformed into a faulted dome with an amplitude of about 1 km. Steep, dip-slip faults form a semi-radial pattern in the roof rocks but are strongly controlled by the regional stress field as many of the faults are sub-parallel to those that form the graben. The longest

  11. Controls on early retention and late enhancement of microporosity in reefal gas reservoirs, offshore north Sumatra basin

    SciTech Connect

    Moshier, S.O.

    1989-03-01

    Chalky lime-matrix texture is pervasive in 300 m of coralgal and skeletal carbonates in the NSB-A (North Sumatra basin-A) gas field (lower-middle Miocene), offshore northern Sumatra. Much of the reservoir quality can be attributed to matrix with abundant intercrystalline, vuggy, and channel-form micropores. Matrix is composed of calcite microrhombs which are interpreted to have developed during stabilization of the precursor mud. On the same shelf, the smaller NSB-H oil field is composed of more than 45-m thick buildup of similar lithofacies which lack abundant microporosity. In both fields, early diagenesis included dissolution of aragonitic skeletal material, matrix neomorphism, and precipitation of nonluminescent calcite followed by zoned, luminescent calcite cements. Stable isotopes from matrix reflect a more open or water-dominated matrix diagenesis at NSB-H field. More active flushing of oversaturated, organically charged meteoric waters was responsible for thorough matrix cementation and microporosity occlusion at NSB-H field. Calcite cements show progressive enrichment of iron and manganese and depletion of magnesium and strontium during growth. The matrix at NSB-H field contains iron-rich dolomite. At A field, remnant matrix microporosity and intraparticle microporosity in calcitic skeletal material were greatly enhanced after all phases of cementation. Some pore-rimming cements are partially dissolved. At NSB-H field, late-phase dissolution is limited to the vicinity of open fractures where matrix-calcite and dolomite crystals are leached. Reservoir brines have a limey marine origin but are depleted in Ca and Mg relative to seawater, and carbon dioxide accounts for 31% of reservoir gas. If present brines are carbonate undersaturated, they may be substantially enhanced microporosity at NSB-A field. Late-stage dissolution is insignificant at NSB-H field due to the lack of early formed matrix microporosity.

  12. Complex Bedforms and Complex Water Masses: A Case Study from the Tertiary to Present-day, Pelotas Basin, Offshore Uruguay

    NASA Astrophysics Data System (ADS)

    Thompson, P.; Badalini, G.; Wrigley, S.; Walker, R.; Argent, J.; Hernandez-Molina, J.; de Santa Ana, H.; Soto, M.; Tomasini, J.

    2015-12-01

    Contour currents are commonly associated with bedform development on modern seabeds yet there is a general paucity of published examples from the ancient record. Recently acquired 3D seismic data, covering over 13000km2 of the Pelotas Basin, offshore Uruguay, provides a unique opportunity to study the architecture and development of a variety of bedform. The data shows that, throughout the Tertiary, contour currents were the dominant control on sedimentation along the Uruguayan margin. The first evidence of contour current activity is during the Early Tertiary in the form of a major regional unconformity that, even though it was fully subaqueous, does not show any major features associated with downslope sedimentation. In the mid-slope region, the unconformity coincides with an extensive (1500km2) intra-slope scour-field orientated parallel to the slope. Individual scours are up to 40m deep, 500m wide and 3km long. Coeval with these scours are a group of coalesced basin floor scours, which run parallel to the base of slope and extend over 400km2. Individual scours exhibit an asymmetric shape - similar to giant flute marks - that are up to 150m deep, 20km wide and extend for at least 40km along slope. The development of these scoured areas shows clear evidence of two major north-flowing water masses. Directly above this regional unconformity are a series of ribbon-like bedforms that developed oblique to the slope. Individual bedforms are up to 40km in length with wavelengths of 5km and heights up to 100m. These bedforms are overlain by a set of barchan-like dunes, up to 30km in length with wavelengths of 10km. Individual dunes are in the order of 100m thick and stack to form an overall package up to 500m thick. These features show a clear change from erosion/bypass to deposition/reworking that is linked to a decrease in ocean current velocity and/ or sediment supply. The features observed suggest a complex oceanic regime was present throughout the Tertiary that

  13. The tectonostratigraphic evolution of the offshore Gippsland Basin, Victoria, Australia---results from 3D seismic interpretation and 2D section restoration

    NASA Astrophysics Data System (ADS)

    Weller, Mitchell

    The Gippsland Basin is located primarily offshore Victoria, Australia (between the Australian mainland and Tasmania) approximately 200 km east of Melbourne. The formation of the east-west trending Gippsland Basin is associated with the break-up of Gondwana during the late Jurassic/early Cretaceous and the basin has endured multiple rifting and inversion events. Strong tectonic control on the sedimentary development of the basin is reflected in the deposition of several major, basin scale sequences ranging in age from the early Cretaceous to Neogene, which are usually bounded by angular unconformities. Schlumberger's Petrel software package has been used to structurally and stratigraphically interpret a basin-wide 3D seismic data set provided by the Australian Government (Geoscience Australia) and four 2D kinematic reconstruction/restorations through the basin have been completed with Midland Valley's Move software to achieve a better understanding of the structural evolution of the Gippsland Basin. Rift phase extension calculated from the restorations (5.0--10.5%) appears anomalously low to accommodate the amount of sediment that has been deposited in the basin (>10km). Distributed extension on small faults and subsidence history from backstripping are employed to answer this anomaly. The 2D restorations completed illustrate structural time relationships across the basin and allow for a minimum estimate of erosion that has occurred along the inverted northern basin margin. Differences between previous work completed by Power et al. (2001) and this study as well as several extension models and associated implications are discussed as they relate to the interpretation carried out in this study. Extension calculated from section restorations ranged from approximately 5.0--10.5%. These measured extensional values appear too low to wholly accommodate the accumulated sediment thickness in the basin. Subsidence modelling and backstripping estimates approximately 50

  14. Mixing mechanisms in siliciclastic-carbonate successions of Khan Formation (Permian), Central Iran

    NASA Astrophysics Data System (ADS)

    Shadan, Mahdi; Hosseini-Barzi, Mahboubeh

    2010-05-01

    Mixing mechanisms in siliciclastic-carbonate successions of Khan Formation (Permian), Central Iran M. Shadan & M. Hosseini-Barzi Geology Department, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran shadangeo@gmail.com Mixing mechanisms in siliciclastic-carbonate successions of Khan Formation (Permian) have been studied in two sections (Chahroof with 197 m thick in north and Cheshmeh Bakhshi with 204 m thick in south) along basement Kalmard fault in Posht-e-Badam block, Central Iran. Siliciclastic units are characterized by well sorted, fine to medium grain quartzarenites with laterite interbeds, deposited in shoreline zone (foreshore, upper and lower shoreface) influencing wave and longshore currents. Longshore sands which have been transported along the coast made the sand bars in the shoreface. Further along the coast, returning of these currents as rip currents produced erosive channel inlets and caused to carry fine grain into the deeper regions of the basin. Based on this sedimentary model we introduced longshore currents as a probable agent for mixing, by transporting some volumes of sands into the adjacent carbonate environments. Vertically, clastic units of Khan Formation underlined by carbonate units of a tidal flat and high-energy inner ramp system. Repeating of this pattern produced 3 cycles in each section. Cyclic evolution, in studied sections, is accompanied with discrepancy in erosion and sedimentation. These factors caused to disperse local sub-aerial exposures in successions which are recognizable by laterite and conglomerate interbeds. These horizons of sub-aerial exposures are more often in Chahroof section than in Cheshmeh Bakhshi section and indicate more fluctuations of relative sea level probably due to more local tectonic activity in the northern part of the Kalmard fault than in the southern part of it. Also, thicker siliciclastic units in Chahroof section show higher rate of sediment supply and/or more accommodation space

  15. 76 FR 69318 - In the Matter of the Designation of Mali Khan also known as Madi Khan as a Specially Designated...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE In the Matter of the Designation of Mali Khan also known as Madi Khan as a Specially Designated Global Terrorist Pursuant to Section 1(b) of Executive Order 13224, as Amended Acting under the authority of and...

  16. Characterization of the Hosgri Fault Zone and adjacent structures in the offshore Santa Maria Basin, south-central California: Chapter CC of Evolution of sedimentary basins/onshore oil and gas investigations - Santa Maria province

    USGS Publications Warehouse

    Willingham, C. Richard; Rietman, Jan D.; Heck, Ronald G.; Lettis, William R.

    2013-01-01

    The Hosgri Fault Zone trends subparallel to the south-central California coast for 110 km from north of Point Estero to south of Purisima Point and forms the eastern margin of the present offshore Santa Maria Basin. Knowledge of the attributes of the Hosgri Fault Zone is important for petroleum development, seismic engineering, and environmental planning in the region. Because it lies offshore along its entire reach, our characterizations of the Hosgri Fault Zone and adjacent structures are primarily based on the analysis of over 10,000 km of common-depth-point marine seismic reflection data collected from a 5,000-km2 area of the central and eastern parts of the offshore Santa Maria Basin. We describe and illustrate the along-strike and downdip geometry of the Hosgri Fault Zone over its entire length and provide examples of interpreted seismic reflection records and a map of the structural trends of the fault zone and adjacent structures in the eastern offshore Santa Maria Basin. The seismic data are integrated with offshore well and seafloor geologic data to describe the age and seismic appearance of offshore geologic units and marker horizons. We develop a basin-wide seismic velocity model for depth conversions and map three major unconformities along the eastern offshore Santa Maria Basin. Accompanying plates include maps that are also presented as figures in the report. Appendix A provides microfossil data from selected wells and appendix B includes uninterpreted copies of the annotated seismic record sections illustrated in the chapter. Features of the Hosgri Fault Zone documented in this investigation are suggestive of both lateral and reverse slip. Characteristics indicative of lateral slip include (1) the linear to curvilinear character of the mapped trace of the fault zone, (2) changes in structural trend along and across the fault zone that diminish in magnitude toward the ends of the fault zone, (3) localized compressional and extensional structures

  17. Well-log signatures of alluvial-lacustrine reservoirs and source rocks, Lagoa-Feia Formations, Lower Cretaceous, Campos Basin, offshore Brazil

    SciTech Connect

    Abrahao, D.; Warme, J.E.

    1988-01-01

    The Campos basin is situated in offshore southeastern Brazil. The Lagoa Feia is the basal formation in the stratigraphic sequence of the basin, and was deposited during rifting in an evolving complex of lakes of different sizes and chemical characteristics, overlying and closely associated with rift volcanism. The stratigraphic sequence is dominated by lacustrine limestones and shales (some of them organic-rich), and volcaniclastic conglomerates deposited on alluvial fans. The sequence is capped by marine evaporites. In the Lagoa Feia Formation, complex lithologies make reservoirs and source rocks unsuitable for conventional well-log interpretation. To solve this problem, cores were studied and the observed characteristics related to log responses. The results have been extended through the entire basin for other wells where those facies were not cored. The reservoir facies in the Lagoa Feia Formation are restricted to levels of pure pelecypod shells (''coquinas''). Resistivity, sonic, neutron, density, and gamma-ray logs were used in this work to show how petrophysical properties are derived for the unconventional reservoirs existing in this formation. The same suite of logs was used to develop methods to define geochemical characteristics where source rock data are sparse in the organic-rich lacustrine shales of the Lagoa Feia Formation. These shales are the main source rocks for all the oil discovered to date in the Campos basin.

  18. Quaternary uplift and subsidence of Catalina Ridge and San Pedro Basin, Inner California Continental Borderland, offshore southern California; results of high-resolution seismic profiling

    NASA Astrophysics Data System (ADS)

    Francis, R.; Legg, M. R.

    2010-12-01

    activity decreased or ceased, as evidenced by the seafloor benches around the island and the flat, onlapping upper sequence of the basin. That the SPBF appears to cut through to the SDTF raises the possibility that a significant share of the motion along the SDTF is now being taken up by the SPBF, at the expense of the CF. Another possibility is that activity along the CF restraining bend is currently being compensated for by broad-scale subsidence within a large offshore synclinorium between Palos Verdes Hills and San Clemente Island, accounting for Catalina Ridge subsidence.

  19. Analysis of ancient-river systems by 3D seismic time-slice technique: A case study in northeast Malay Basin, offshore Terengganu, Malaysia

    SciTech Connect

    Sulaiman, Noorzamzarina; Hamzah, Umar; Samsudin, Abdul Rahim

    2014-09-03

    Fluvial sandstones constitute one of the major clastic petroleum reservoir types in many sedimentary basins around the world. This study is based on the analysis of high-resolution, shallow (seabed to 500 m depth) 3D seismic data which generated three-dimensional (3D) time slices that provide exceptional imaging of the geometry, dimension and temporal and spatial distribution of fluvial channels. The study area is in the northeast of Malay Basin about 280 km to the east of Terengganu offshore. The Malay Basin comprises a thick (> 8 km), rift to post-rift Oligo-Miocene to Pliocene basin-fill. The youngest (Miocene to Pliocene), post-rift succession is dominated by a thick (1–5 km), cyclic succession of coastal plain and coastal deposits, which accumulated in a humid-tropical climatic setting. This study focuses on the Pleistocene to Recent (500 m thick) succession, which comprises a range of seismic facies analysis of the two-dimensional (2D) seismic sections, mainly reflecting changes in fluvial channel style and river architecture. The succession has been divided into four seismic units (Unit S1-S4), bounded by basin-wide strata surfaces. Two types of boundaries have been identified: 1) a boundary that is defined by a regionally-extensive erosion surface at the base of a prominent incised valley (S3 and S4); 2) a sequence boundary that is defined by more weakly-incised, straight and low-sinuosity channels which is interpreted as low-stand alluvial bypass channel systems (S1 and S2). Each unit displays a predictable vertical change of the channel pattern and scale, with wide low-sinuosity channels at the base passing gradationally upwards into narrow high-sinuosity channels at the top. The wide variation in channel style and size is interpreted to be controlled mainly by the sea-level fluctuations on the widely flat Sunda land Platform.

  20. Depositional environments and source rock investigations of the Oligocene to Middle Miocene deposits in the Ardjuna Basin, offshore Northwest Java, Indonesia

    SciTech Connect

    Wu Chiahsin Charlie.

    1991-01-01

    Investigations of depositional environments, paleogeographic evolution, source rock potential/maturity, and petroleum generation, expulsion, migration and accumulation were performed on the Oligocene to Middle Miocene deposits in the Ardjuna Basin, offshore Northwest Java, using integrated geologic, seismic and geochemical approaches. The Oligocene to Middle Miocene sediments were deposited in a generally transgressive sequence. It is the most prospective stratigraphic unit for petroleum exploration in the Ardjuna Basin. The rocks comprise three Formations: Talang Akar, Baturaja and Cibulakan. Paleogeography of six stages within the study interval, showing the degree of marine transgression were mapped based on integrated biostratigraphic, paleoenvironmental, and seismic-stratigraphic data. The coals and carbonaceous shales deposited in the deltaic and nearshore environment of the Talang Akar Formation are petroleum source rocks for the waxy oils produced in the Ardjuna Basin. The organic matter contains predominantly vitrinite maceral and up to 30% exinite maceral. Source rock temperature, after calibration with vitrinite reflectance, provides an accurate quantitative measurement for predicting the level of thermal maturation. Two geochemical approaches were used and compared in petroleum resource assessment: petroleum yield (S1) method and genetic potential (S2) method. The oil generative kitchen, the Ardjuna depocenter, has the best opportunity for new oil discovery. This model has since been proved by subsequent drilling leading to several oil discoveries in the last two years.

  1. The geologic boundary between the northern part of the Socotra Basin and the Fukien-Reinan Massif, offshore Korea: Implementations in marine magnetics

    NASA Astrophysics Data System (ADS)

    Suh, M.; Abdallatif, T. F.; Oh, J.; Choi, S.; Han, J.

    2010-03-01

    A detailed marine magnetic survey of the region southwest of Jeju Island, offshore Korea, reveals the boundary between the northern part of the Socotra Basin (SB) and the Fukien-Reinan Massif (FRM). To delineate the boundary and highlight its origin, several interpretation methods have been applied. Low and band pass filtering; upward-continuation filtering; horizontal gradient (HG) transformation and 2½D methods delineate the boundary in the subsurface basement. Analysis of the magnetic amplitudes through three selected profiles provides a good correlation between the applied methods and exposes the magnetic sources on and around the boundary. The modeling of magnetic anomalies northwest of the Socotra Basin revealed the edge lines between the adjacent subsurface geological units. Among the applied methods, the results of the horizontal gradient method were prominent in clarifying distinctly the location of this important boundary. These results are shown in addition to the results of other interpretation tools that the boundary is located in the shallow section of the northwestern part of the SB. Based on these results, FRM is probably sandwiched between two identified boundaries in the northwestern portion of the northern part of the SB. These results are consistent with earlier recent studies over the same area, and will lead to a better understanding of the geology of this neglected region and the East China Sea Shelf Basin in general.

  2. Morphology and evolution of salt/mini-basin systems: Lower shelf and upper slope, central offshore Louisiana

    SciTech Connect

    Sumner, H.S.; Robinson, B.A.; Dirks, W.K.; Holliday, J.C. )

    1991-03-01

    A complex array of deformed salt bodies and localized salt withdrawal depocenters termed 'mini-basins' dominate the subsurface geology of the central Louisiana lower shelf and upper slope. Individual salt bodies climb basinward as horizontal sills supplied by vertical to inclined 'feeders.' Each level of salt remobilization and emplacement is overlain by an association of structural features that occurs repetitively in space and time owing to sediment loading caused by progradation of Miocene to Recent shelf margins. Mini-basins are generally circular to elliptical (in map view) and contain thick sequences of sediment ponded by salt withdrawal. Mini-basins on the slope typically have a simple symmetric to asymmetric internal structure and are often almost entirely bounded by large, bathymetrically high salt bodies. Salt displaced out of slope mini-basins is loaded by the advancing shelf margin, initiating formation of shelf mini-basins. Shelf mini-basins generally have well-defined fault/piercement salt boundaries and a strongly asymmetric to the south internal structure. Salt displaced downdip by shelf mini-basin loading forms major shallow-seated sill-like bodies that intrude upper slope strata. Subsequent reactivation of these allochthonous salt sills often results in a secondary level of structural features that detach on a salt withdrawal surface ('Roho'). Salt/mini-basin systems exert a profound influence on hydrocarbon distribution. Current production occurs mainly in traps associated with shelf mini-basins. Additional production occurs in traps found above reactived salt sills ('Rohos') on the shelf. Industry exploration is presently focused on identification of traps in the slope mini-basin setting.

  3. Nature of the uppermost mantle below the Porcupine Basin, offshore Ireland: new insights from seismic refraction and gravity data modeling

    NASA Astrophysics Data System (ADS)

    Prada, M.; Watremez, L.; Chen, C.; O'Reilly, B.; Minshull, T. A.; Reston, T. J.; Wagner, G.; Gaw, V.; Klaeschen, D.; Shannon, P.

    2015-12-01

    The Porcupine Basin is a tongue-shaped basin SW of Ireland formed during the opening of the North Atlantic Ocean. Its history of sedimentation reveals several rifting and subsidence phases during the Late Paleozoic and Cenozoic, with a particular major rift phase occurring in Late Jurassic-Early Cretaceous times. Previous work, focused on seismic and gravity data, suggest the presence of major crustal faulting and uppermost mantle serpentinization in the basin. Serpentinization is a key factor in lithospheric extension since it reduces the strength of mantle rocks, and hence, influences the tectonics of the lithosphere. Besides reducing the seismic velocity of the rock, serpentinization decreases mantle rock density favoring isostatic rebound and basin uplift, thus affecting the tectonic and thermal evolution of the basin. Here we characterize the deep structure of the Porcupine Basin from wide-angle seismic (WAS) and gravity data, with especial emphasis on the nature of the underlying mantle. The WAS data used were acquired along a 300 km long transect across the northern region of the basin. We used a travel time inversion method to model the data and obtain a P-wave velocity (Vp) model of the crust and uppermost mantle, together with the geometry of the main geological interfaces. The crustal structure along the model reveals a maximum stretching factor of ~5-6. These values are well within the range of crustal extension at which the crust becomes entirely brittle allowing the formation of major crustal faulting and serpentinization of the mantle. To further constrain the seismic structure and hence the nature of the mantle we assess the Vp uncertainty of the model by means of a Monte Carlo analysis and perform gravity modeling to test different interpretations regarding mantle rock nature. This project is funded by the Irish Shelf Petroleum Studies Group (ISPSG) of the Irish Petroleum Infrastructure Programme Group 4.

  4. Sand-rich submarine fans, Mio-Pliocene of Santa Monica Basin, offshore California: Untapped exploration targets

    SciTech Connect

    May, J.A.; McMillen, K.J.

    1996-01-01

    Santa Monica Basin lies directly west of Los Angeles Basin, one of the world's most prolific oil provinces. Published literature suggests that Santa Monica Basin was starved of coarse clastics during the late Miocene through Pliocene. However, seismic sequence stratigraphy indicates that deposition of sand-rich fans alternated with mixed-load systems throughout the Delmontian and Repettian stages. Seismic sequences and facies are calibrated to seismic and well data from Beta Oil Field, in San Pedro Basin to the south. Eustasy evidently played a dominant role in controlling sedimentation. Variations in tan lithology, thickness, and basinward extent correspond to worldwide changes in sea level. Regional erosion surfaces apparently signify drops in sea level. Overlying thick seismic packages display hummocky to chaotic seismic facies separated by high- to low-amplitude continuous reflections. These configurations are interpreted as inner- to mid-fan channels separated by overbank deposits in sand-rich lowstand fans. High-amplitude basinwide reflections bound the tops of the sand-rich intervals, and likely represent condensed sections formed during sea-level rises. Thin seismic intervals above the condensed sections display downlap, and are interpreted as interbedded sandstones and shales of prograding highstand fans. Sediment input to Santa Monica Basin, based on seismic-facies and isochron patterns, was predominantly from the (present-day) north, with subordinate input from the east. High-amplitude eustatic variations dominated deposition and sequence development even in this tectonically active basin Previously unidentified sand-rich fans are present, and have not been drilled.

  5. Sand-rich submarine fans, Mio-Pliocene of Santa Monica Basin, offshore California: Untapped exploration targets

    SciTech Connect

    May, J.A.; McMillen, K.J.

    1996-12-31

    Santa Monica Basin lies directly west of Los Angeles Basin, one of the world`s most prolific oil provinces. Published literature suggests that Santa Monica Basin was starved of coarse clastics during the late Miocene through Pliocene. However, seismic sequence stratigraphy indicates that deposition of sand-rich fans alternated with mixed-load systems throughout the Delmontian and Repettian stages. Seismic sequences and facies are calibrated to seismic and well data from Beta Oil Field, in San Pedro Basin to the south. Eustasy evidently played a dominant role in controlling sedimentation. Variations in tan lithology, thickness, and basinward extent correspond to worldwide changes in sea level. Regional erosion surfaces apparently signify drops in sea level. Overlying thick seismic packages display hummocky to chaotic seismic facies separated by high- to low-amplitude continuous reflections. These configurations are interpreted as inner- to mid-fan channels separated by overbank deposits in sand-rich lowstand fans. High-amplitude basinwide reflections bound the tops of the sand-rich intervals, and likely represent condensed sections formed during sea-level rises. Thin seismic intervals above the condensed sections display downlap, and are interpreted as interbedded sandstones and shales of prograding highstand fans. Sediment input to Santa Monica Basin, based on seismic-facies and isochron patterns, was predominantly from the (present-day) north, with subordinate input from the east. High-amplitude eustatic variations dominated deposition and sequence development even in this tectonically active basin Previously unidentified sand-rich fans are present, and have not been drilled.

  6. Natural Offshore Oil Seepage and Related Tarball Accumulation on the California Coastline - Santa Barbara Channel and the Southern Santa Maria Basin: Source Identification and Inventory

    USGS Publications Warehouse

    Lorenson, T.D.; Hostettler, Frances D.; Rosenbauer, Robert J.; Peters, Kenneth E.; Dougherty, Jennifer A.; Kvenvolden, Keith A.; Gutmacher, Christina E.; Wong, Florence L.; Normark, William R.

    2009-01-01

    Oil spillage from natural sources is very common in the waters of southern California. Active oil extraction and shipping is occurring concurrently within the region and it is of great interest to resource managers to be able to distinguish between natural seepage and anthropogenic oil spillage. The major goal of this study was to establish the geologic setting, sources, and ultimate dispersal of natural oil seeps in the offshore southern Santa Maria Basin and Santa Barbara Basins. Our surveys focused on likely areas of hydrocarbon seepage that are known to occur between Point Arguello and Ventura, California. Our approach was to 1) document the locations and geochemically fingerprint natural seep oils or tar; 2) geochemically fingerprint coastal tar residues and potential tar sources in this region, both onshore and offshore; 3) establish chemical correlations between offshore active seeps and coastal residues thus linking seep sources to oil residues; 4) measure the rate of natural seepage of individual seeps and attempt to assess regional natural oil and gas seepage rates; and 5) interpret the petroleum system history for the natural seeps. To document the location of sub-sea oil seeps, we first looked into previous studies within and near our survey area. We measured the concentration of methane gas in the water column in areas of reported seepage and found numerous gas plumes and measured high concentrations of methane in the water column. The result of this work showed that the seeps were widely distributed between Point Conception east to the vicinity of Coal Oil Point, and that they by in large occur within the 3-mile limit of California State waters. Subsequent cruises used sidescan and high resolution seismic to map the seafloor, from just south of Point Arguello, east to near Gaviota, California. The results of the methane survey guided the exploration of the area west of Point Conception east to Gaviota using a combination of seismic instruments. The

  7. Geology, exploration status of Uruguay's sedimentary basins

    SciTech Connect

    Goso, C.; Santa Ana, H. de )

    1994-02-07

    This article attempts to present the geological characteristics and tectonic and sedimentary evolution of Uruguayan basins and the extent to which they have been explored. Uruguay is on the Atlantic coast of South America. The country covers about 318,000 sq km, including offshore and onshore territories corresponding to more than 65% of the various sedimentary basins. Four basins underlie the country: the Norte basin, the Santa Lucia basin, the offshore Punta del Este basin, and the offshore-onshore Pelotas-Merin basin. The Norte basin is a Paleozoic basin while the others are Mesozoic basins. Each basin has been explored to a different extent, as this paper explains.

  8. Association among active seafloor deformation, mound formation, and gas hydrate growth and accumulation within the seafloor of the Santa Monica Basin, offshore California

    USGS Publications Warehouse

    Paull, C.K.; Normark, W.R.; Ussler, W., III; Caress, D.W.; Keaten, R.

    2008-01-01

    Seafloor blister-like mounds, methane migration and gas hydrate formation were investigated through detailed seafloor surveys in Santa Monica Basin, offshore of Los Angeles, California. Two distinct deep-water (??? 800??m water depth) topographic mounds were surveyed using an autonomous underwater vehicle (carrying a multibeam sonar and a chirp sub-bottom profiler) and one of these was explored with the remotely operated vehicle Tiburon. The mounds are > 10??m high and > 100??m wide dome-shaped bathymetric features. These mounds protrude from crests of broad anticlines (~ 20??m high and 1 to 3??km long) formed within latest Quaternary-aged seafloor sediment associated with compression between lateral offsets in regional faults. No allochthonous sediments were observed on the mounds, except slumped material off the steep slopes of the mounds. Continuous streams of methane gas bubbles emanate from the crest of the northeastern mound, and extensive methane-derived authigenic carbonate pavements and chemosynthetic communities mantle the mound surface. The large local vertical displacements needed to produce these mounds suggests a corresponding net mass accumulation has occurred within the immediate subsurface. Formation and accumulation of pure gas hydrate lenses in the subsurface is proposed as a mechanism to blister the seafloor and form these mounds. ?? 2008 Elsevier B.V. All rights reserved.

  9. In situ stress and pore pressure in the Kumano Forearc Basin, offshore SW Honshu from downhole measurements during riser drilling

    NASA Astrophysics Data System (ADS)

    Saffer, D. M.; Flemings, P. B.; Boutt, D.; Doan, M.-L.; Ito, T.; McNeill, L.; Byrne, T.; Conin, M.; Lin, W.; Kano, Y.; Araki, E.; Eguchi, N.; Toczko, S.

    2013-05-01

    situ stress and pore pressure are key parameters governing rock deformation, yet direct measurements of these quantities are rare. During Integrated Ocean Drilling Program (IODP) Expedition #319, we drilled through a forearc basin at the Nankai subduction zone and into the underlying accretionary prism. We used the Modular Formation Dynamics Tester tool (MDT) for the first time in IODP to measure in situ minimum stress, pore pressure, and permeability at 11 depths between 729.9 and 1533.9 mbsf. Leak-off testing at 708.6 mbsf conducted as part of drilling operations provided a second measurement of minimum stress. The MDT campaign included nine single-probe (SP) tests to measure permeability and in situ pore pressure and two dual-packer (DP) tests to measure minimum principal stress. Permeabilities defined from the SP tests range from 6.53 × 10-17 to 4.23 × 10-14 m2. Pore fluid pressures are near hydrostatic throughout the section despite rapid sedimentation. This is consistent with the measured hydraulic diffusivity of the sediments and suggests that the forearc basin should not trap overpressures within the upper plate of the subduction zone. Minimum principal stresses are consistently lower than the vertical stress. We estimate the maximum horizontal stress from wellbore failures at the leak-off test and shallow MDT DP test depths. The results indicate a normal or strike-slip stress regime, consistent with the observation of abundant active normal faults in the seaward-most part of the basin, and a general decrease in fault activity in the vicinity of Site C0009.

  10. Crowdsourcing the Unknown: The Satellite Search for Genghis Khan

    PubMed Central

    Lin, Albert Yu-Min; Huynh, Andrew; Lanckriet, Gert; Barrington, Luke

    2014-01-01

    Massively parallel collaboration and emergent knowledge generation is described through a large scale survey for archaeological anomalies within ultra-high resolution earth-sensing satellite imagery. Over 10K online volunteers contributed 30K hours (3.4 years), examined 6,000 km2, and generated 2.3 million feature categorizations. Motivated by the search for Genghis Khan's tomb, participants were tasked with finding an archaeological enigma that lacks any historical description of its potential visual appearance. Without a pre-existing reference for validation we turn towards consensus, defined by kernel density estimation, to pool human perception for “out of the ordinary” features across a vast landscape. This consensus served as the training mechanism within a self-evolving feedback loop between a participant and the crowd, essential driving a collective reasoning engine for anomaly detection. The resulting map led a National Geographic expedition to confirm 55 archaeological sites across a vast landscape. A increased ground-truthed accuracy was observed in those participants exposed to the peer feedback loop over those whom worked in isolation, suggesting collective reasoning can emerge within networked groups to outperform the aggregate independent ability of individuals to define the unknown. PMID:25549335

  11. Silicate Weathering and Pervasive Authigenic Carbonate Precipitation Coupled to Methanogenesis in the Krishna-Godavari Basin, Offshore India

    NASA Astrophysics Data System (ADS)

    Solomon, E. A.; Spivack, A. J.; Kastner, M.; Torres, M. E.

    2014-12-01

    The cycling of methane in marine sediments has been actively studied for the past several decades, but less attention has been paid to the cycling of CO2 produced in methanogenic sediments. The National Gas Hydrate Program Expedition 01 cored 10 sites with the Joides Resolution drillship in the Krishna-Godavari basin, located on the southeastern margin of India. A comprehensive suite of pore water solute concentrations and isotope ratios were analyzed to investigate the distribution and concentration of gas hydrate along the margin, in situ diagenetic and metabolic reactions, fluid migration and flow pathways, and fluid and gas sources. This represents one of the most comprehensive pore water geochemical datasets collected at a continental margin to date, and provides the necessary tracers to better understand the processes and sinks controlling CO2 in margin sediments. Our results show that the CO2 produced through net microbial methanogenesis is effectively neutralized through silicate weathering throughout the sediment column drilled at each site (~100-300 m), buffering the pH of the sedimentary pore water and generating excess alkalinity through the same reaction sequence as continental silicate weathering. Most of the excess alkalinity produced through silicate weathering in the Krishna-Godavari basin is sequestered in Ca- and Fe-carbonates as a result of ubiquitous calcium release from weathering detrital silicates and Fe-reduction within the methanogenic sediments. Formation of secondary hydrous silicates (e.g. smectite) related to incongruent primary silicate dissolution acts as a significant sink for pore water Mg, K, Li, Rb, and B. The consumption of methane through anaerobic oxidation of methane, sequestration of methane in gas hydrate, and sequestration of dissolved inorganic carbon in authigenic carbonates keeps methanogenesis as a thermodynamically feasible catabolic pathway. Our results combined with previous indications of silicate weathering in

  12. Subsurface plumbing and fluid expulsion from sedimentary basins: evidence from the sedimentary record offshore West Africa (Invited)

    NASA Astrophysics Data System (ADS)

    Huuse, M.

    2010-12-01

    Many petroliferous basins around the world show evidence for fluid expulsion and seepage on the land surface or seafloor. However, not all fluid expulsion features are evidence of a working hydrocarbon systems and one needs to carefully evaluate fluid expulsion features and their associated geology and in particular their plumbing systems before inferring the nature of the expelled fluids. Geochemical fingerprinting of the migrating fluids may be sampled directly or via carbonate cements secreted in association with focus fluid conduits and may help determine the nature of the expelled fluids including their stratigraphic origin. When such evidence is unavailable, one may have to rely on remote sensing, including 3D seismic characterization in order to assess the nature of expelled fluids and links with hydrocarbon migration and/or ‘normal’ diagenetic fluid expulsion. This paper presents 3D seismic case studies of pockmarks, fluid flow pipes and polygonal fault systems which show evidence of both deep and shallow sources of expelled fluids and discuss the different controls on their occurrence and significance. Importantly, there is evidence of both conducting and sealing behaviours of polygonal fault sytems. Bottom-Simulating Reflections from interfaces between free gas and overlying gas hydrate occur in a variety of manifestations and may be linked with both deep and shallow sources of methane. Their depth of occurrence relative to seafloor depth may be used to infer local geothermal gradients and it is shown that underlying salt causes BSRs to shallow, indicative of a doubling of the geothermal gradient above salt structures compared to the adjacent salt mini basins. It is further suggested that salt structures on the middle slope serve a dual purpose as trap and leak-forming features, with traps focused on the down-dip side of overhanging diapirs and leaks located on the updip side and flanks. Associated leakage phenomena include gas and gas hydrate

  13. Active deformation in the frontal part of the Northern Apennines: insights from the lower Metauro River basin area (northern Marche, Italy) and adjacent Adriatic off-shore

    NASA Astrophysics Data System (ADS)

    Di Bucci, D.; Mazzoli, S.; Nesci, O.; Savelli, D.; Tramontana, M.; De Donatis, M.; Borraccini, F.

    2003-09-01

    An integration of seismological data with geological and geomorphological information aided by seismic interpretation was performed to characterise the Quaternary tectonic evolution of the Metauro River basin area (northern Marche) and adjacent off-shore sector of the external Northern Apennines. On-shore, along the Adriatic coast, the youngest age of thrusting and folding post-dates the Early-Middle Pliocene, while Pleistocene deposits appear to be, at least in part, not involved in the deformation. Recent (i.e. post-thrusting) tectonic structures have been recognised both in pre-Quaternary substratum rocks and in Upper Quaternary continental deposits (Upper Pleistocene terrace alluvium, Upper Pleistocene-Holocene slope deposits). These faults are all compatible with a WSW-ENE oriented extension. In the Metauro River basin area, preserved flights of stream terraces have been categorised according to the presence or absence of alluvial suites in relationship to each terrace level. Here, based on both the heights above the valley floor and the areal distribution of stream terraces, a generalised vertical tectonic uplift can be inferred, particularly during the Middle-Late Pleistocene. Moreover, the along-valley distribution of stream terraces provides further constraints on the age of thrusting and folding. In fact, the reconstructed terrace-levels are substantially parallel, and no evidence for any significant deformation by fold activity has been recognised. Local deformation displayed by both terrace surfaces and alluvial/slope-waste deposits suggests, instead, the intervening of some minor differential movements associated with the generalised uplift and/or to Middle-Late Pleistocene normal faulting. Their occurrence appears anyhow to be unrelated with the pattern of folds and associated thrusts. The present-day seismic activity of the study area was considered by analysing 83 seismic events that occurred from 1987 to 2000. The epicentre distribution is very

  14. Gas in Place Resource Assessment for Concentrated Hydrate Deposits in the Kumano Forearc Basin, Offshore Japan, from NanTroSEIZE and 3D Seismic Data

    NASA Astrophysics Data System (ADS)

    Taladay, K.; Boston, B.

    2015-12-01

    Natural gas hydrates (NGHs) are crystalline inclusion compounds that form within the pore spaces of marine sediments along continental margins worldwide. It has been proposed that these NGH deposits are the largest dynamic reservoir of organic carbon on this planet, yet global estimates for the amount of gas in place (GIP) range across several orders of magnitude. Thus there is a tremendous need for climate scientists and countries seeking energy security to better constrain the amount of GIP locked up in NGHs through the development of rigorous exploration strategies and standardized reservoir characterization methods. This research utilizes NanTroSEIZE drilling data from International Ocean Drilling Program (IODP) Sites C0002 and C0009 to constrain 3D seismic interpretations of the gas hydrate petroleum system in the Kumano Forearc Basin. We investigate the gas source, fluid migration mechanisms and pathways, and the 3D distribution of prospective HCZs. There is empirical and interpretive evidence that deeply sourced fluids charge concentrated NGH deposits just above the base of gas hydrate stability (BGHS) appearing in the seismic data as continuous bottoms simulating reflections (BSRs). These HCZs cover an area of 11 by 18 km, range in thickness between 10 - 80 m with an average thickness of 40 m, and are analogous to the confirmed HCZs at Daini Atsumi Knoll in the eastern Nankai Trough where the first offshore NGH production trial was conducted in 2013. For consistency, we calculated a volumetric GIP estimate using the same method employed by Japan Oil, Gas and Metals National Corporation (JOGMEC) to estimate GIP in the eastern Nankai Trough. Double BSRs are also common throughout the basin, and BGHS modeling along with drilling indicators for gas hydrates beneath the primary BSRs provides compelling evidence that the double BSRs reflect a BGHS for structure-II methane-ethane hydrates beneath a structure-I methane hydrate phase boundary. Additional drilling

  15. High Resolution Mapping of an Alleged Chemical Weapons Dump Site in the Santa Cruz Basin, offshore California

    NASA Astrophysics Data System (ADS)

    Brewer, P. G.; Peltzer, E. T.; Walz, P. M.; Caress, D. W.; Thomas, H. J.

    2013-12-01

    Nautical charts record seven locations off the coast of California labeled as 'Chemical Munitions Dumping Area, Disused' that together cover some 12,000 km2 of sea floor. However only one such chemical munitions site is officially documented and no record exists of any chemical munitions disposed of at other locations, thus creating confusion. We have executed a one day AUV mapping survey of a corner of one such site in the Santa Cruz Basin, south of Port Hueneme, to examine and investigate the debris field. The region is covered with soft sediment and the overlying water is very low in oxygen at ~10 μmol/kg. The processed 110 kHz sidescan data revealed some 754 targets in 25.6 km2 for an average of 29 targets per km2. This was followed by two ROV dives to investigate the targets identified. We found but one false positives among the over 40 targets visited, and found items ranging from two distinct lines of unmarked or labeled and now empty barrels, two target drones, and much miscellaneous debris including 4-packs of cat food cans and a large ships mast over 30m in length. There was zero evidence of chemical weapons materiel as expected given the lack of official records. Almost all of the targets were covered in dense and colorful assemblages of invertebrates: sponges, anemones, and crabs. Where barrels were sufficiently open for full visual inspection, the interior sea floor appeared to have become fully anoxic and was covered in white and yellow bacterial mat. The area chosen for our survey (centered at 33.76 deg N 119.56 deg W) was across the north western boundary of the marked site, and represents only ~ 10% percent of the designated area. Our expectation, that human nature would drive the disposal activities to the nearest corner of the chosen area rather than the center of the field appears to have been confirmed. Objects were found both within and outside of the boundary of the dump site. We have not surveyed the full marked area but there appears to be

  16. Assessment of Mass-Transport Deposits occurrence offshore Espírito Santo Basin (SE Brazil) using a bivariate statistical method

    NASA Astrophysics Data System (ADS)

    Piedade, Aldina; Alves, Tiago; Luís Zêzere, José

    2016-04-01

    Mass Transport Deposits (MTDs) are one of the most important process shaping passive and active margins. It is frequently happening and its characteristics, features and processes has been very well documented from diverse approaches and methodologies. In this work a methodology for evaluation of MTDs occurrence is tested in an area offshore Espírito Santo Basin, SE Brazil. MTDs inventory was made on three-dimensional (3D) seismic volume interpreting a high amplitude reflection which correspond to the top and base of the MTDs. The inventory consists of four MTDs which were integrated into a GIS database. MTDs favourability scores are computed using algorithms based on statistical/probabilistic analysis (Information Value Method) over unique condition terrain units in a raster basis. Terrain attributes derived from the Digital Terrain Model (DTM) are interpreted as proxies of driving factors of MTDs and are used as predictors in our models which are based on a set of different MTDs inventories. Three models are elaborated independently according to the area of the MTDs body (Model 1, Model 2 and Model 3). The final result is prepared by sorting all pixels according to the pixel favourability value in descending order. The robustness and accuracy of the MTDs favourability models are evaluated by the success-rate curves, which are used for the quantitative interpretation of the models expressing the goodness of fit of the MTDs. In addition, a sensitivity analysis was performed and the predisposing factors which have highest prediction performance on MTDs occurrence were identified. The obtained results allow to conclude the method is valid to apply to submarine slopes as it is demonstrated by the highest obtained goodness of fit (0.862). This work is very pioneer, the methodology used was never applied to submarine environment. It is a very promising and valid methodology within the prediction of submarine slopes regarding failing and instability to the industry. In

  17. A Case Study for Teaching Quantitative Biochemical Buffer Problems Using Group Work and "Khan Style" Videos

    ERIC Educational Resources Information Center

    Barreto, Jose; Reilly, John; Brown, David; Frost. Laura; Coticone, Sulekha Rao; Dubetz, Terry Ann; Beharry, Zanna; Davis-McGibony, C. Michele; Ramoutar, Ria; Rudd, Gillian

    2014-01-01

    New technological developments have minimized training, hardware expense, and distribution problems for the production and use of instructional videos, and any science instructor can now make instructional videos for their classes. We created short "Khan style" videos for the topic of buffers in biochemistry and assigned them as…

  18. Increasing Student Engagement in Math: The Use of Khan Academy in Chilean Classrooms

    ERIC Educational Resources Information Center

    Light, Daniel; Pierson, Elizabeth

    2014-01-01

    Khan Academy, an online platform offering educational videos and exercises in different content areas, has awakened intense interest among foundations, multilateral organizations, policy makers, and educators about how this tool can help meet the educational challenges facing countries around the world. With support from Intel, Education…

  19. Parents' Attitude toward Daughters' Education in Tribal Area of Dera Ghazi Khan (Pakistan)

    ERIC Educational Resources Information Center

    Buzdar, Muhammad Ayub; Ali, Akhtar

    2011-01-01

    The paper aimed to investigate the parents' attitudes toward their daughters' education in tribal areas of district Dera Ghazi Khan (Pakistan). To achieve the objectives four research questions were established. Focus of the questions was to examine the significance of girls' education for tribal parents. Existing and expected role of tribal…

  20. Shaping Influences on the Leadership of Genghis Khan, George Washington, and Nelson Mandela: Applications for Educators

    ERIC Educational Resources Information Center

    Bongila, Jean-Pierre

    2011-01-01

    Using a prosopographical methodology this study examines common leadership influences that might have existed among Genghis Khan, George Washington, and Nelson Mandela. Shoup (2005) suggests that the following seven influences have contributed to nurturing the leadership of 12 renowned individuals: involved parents, happy childhood, formal,…

  1. KHAN DU! II. Final Project Performance Report, November 1, 1978-September 30, 1979.

    ERIC Educational Resources Information Center

    KLRN/KLRU-TV, Austin, TX.

    This KHAN DU! project produced four half-hour television programs in the area of career education with emphasis on the handicapped, plus an extra nonbroadcast program designed for teachers. The four-program series was designed for children aged eight to eleven, although older children have responded favorably. The goals of the series were (1) to…

  2. The magnetostratigraphy of the Chitarwata and lower Vihowa formations of the Dera Ghazi Khan area, Pakistan

    NASA Astrophysics Data System (ADS)

    Friedman, Rachel; Gee, Jeff; Tauxe, Lisa; Downing, Kevin; Lindsay, Everett

    1992-12-01

    Three sections of the Chitarwata and lower Vihowa formations were sampled along the Dalana River on the southeastern flank of the Zinda Pir Dome in the southern Sulaiman Range near Dera Ghazi Khan, Pakistan. Together they provide nearly 800 m of a continuous sedimentary record of the Miocene derived from the uplifted Himalayan highlands. Previous studies have examined the Middle and Upper Miocene sediments, the Siwalik Group, of the Potwar Plateau to the north. However, detailed investigations of earlier periods are impossible in that area due to the absence of Oligocene and Lower Miocene sediments caused by continued overthrusting associated with the Himalayan orogeny. Fortunately, the Sulaiman basin to the south, which was further removed from the tectonic activity, provides a record of the Early Miocene in the form of the Chitarwata Formation. The Dalana A, B, and C sections (DGA, DGB, and DGC) were examined and sampled for this study. A magnetostratigraphic analysis was carried out to correlate and date the Chitarwata and Vihowa formations exposed in this area. The samples were subjected to step-wise demagnetization to resolve the primary and secondary remanent magnetization components. Thermal demagnetization trajectories indicate that the majority of samples have sufficient internal consistency that their calculated polarities are reliable. Likewise, the majority of the 126 measured sites showed statistically significant agreement between the three measured samples per site. However, the bimodal data set does not pass the reversal test and so is deemed unsuitable for tectonic interpretations. The individual sections were initially correlated using lithologic and stratigraphic methods, and the relationship was reinforced by the magnetostratigraphy. The composite DG section was tentatively correlated with the standard magnetic polarity time scale placing the disconformable base of the Chitarwata in the DGA section at just older than 22 Ma, the Chitarwata

  3. Global Sea-Level Versus Local Control of Middle-Miocene to Recent Sequences on a Current-Swept Divergent Margin: Offshore Canterbury Basin, New Zealand

    NASA Astrophysics Data System (ADS)

    Lu, H.; Fulthorpe, C. S.; Mann, P.

    2002-12-01

    Upper Miocene to Recent sequences beneath the continental shelf and slope of the offshore Canterbury Basin, New Zealand, are mapped using closely spaced, high-resolution multichannel seismic data collected in January 2000. Sequence geometries and morphologies of unconformities reflect competing influences of eustasy, contour-currents, and rate of sediment supply. Eighteen regional sequence-bounding unconformities form three seismic stratigraphic units: 1) Miocene unconformities U1-8 (>16-5 Ma; all ages are from ODP Site 1119 and Clipper exploration well) have smooth shelves. Onlap can occur on both shelf and slope. Most sequences are progradational and of relatively long duration (>1.4 m.y.). Six additional localized unconformities also occur; each onlaps the underlying regional unconformity and is either truncated basinward by sediment drifts or downlaps onto the underlying unconformity. 2) Pliocene to early Pleistocene unconformities U9-13 (3.6-1.25 Ma) define aggradational sequences with durations ranging from 0.11 to 1.4 m.y. Frequency of onlap decreases up section. Each sequence contains a downlap surface, which onlaps the underlying unconformity and is truncated basinward by the overlying unconformity. 3) Early Pleistocene (~1.2 Ma) to Recent unconformities U14-18 display shelf channel incision and erosional truncation by currents on the slope. Sequences are progradational and of short duration (<0.4 m.y.). They are downlapped on the shelf and slope failure truncates reflections near their well-defined shelf edges. Five additional local unconformities are truncated to landward by the overlying regional unconformity; most are only preserved on the outer shelf and upper slope. The most recent unconformities (17 and 18, plus three local unconformities) correlate well with 100 k.y. cycles in the oxygen isotope record (stages 6-14) over the last 500 k.y., suggesting that they are of eustatic origin. Older sequences are of longer duration and encompass multiple

  4. Depth-to-basement, sediment-thickness, and bathymetry data for the deep-sea basins offshore of Washington, Oregon, and California

    USGS Publications Warehouse

    Wong, Florence L.; Grim, Muriel S.

    2015-01-01

    Contours and derivative raster files of depth-to-basement, sediment-thickness, and bathymetry data for the area offshore of Washington, Oregon, and California are provided here as GIS-ready shapefiles and GeoTIFF files. The data were used to generate paper maps in 1992 and 1993 from 1984 surveys of the U.S. Exclusive Economic Zone by the U.S. Geological Survey for depth to basement and sediment thickness, and from older data for the bathymetry.

  5. Building a three-dimensional geological model of the Pegasus Basin (offshore New Zealand) with the aim of improving our understanding of gas hydrate distribution

    NASA Astrophysics Data System (ADS)

    Crutchley, G. J.; Barnes, P.; Kroeger, K. F.; Hill, M.; Mountjoy, J. J.; Pecher, I. A.

    2014-12-01

    The Pegasus Basin, on the southern end of New Zealand's Hikurangi margin, developed as a passive margin from the end of subduction along the Chatham Rise around 105 Ma to the initiation of the modern plate boundary around 25 Ma. Multi-channel seismic reflection data acquired by the New Zealand government in 2009 and 2010 show well-developed bottom-simulating reflections (BSRs) throughout the basin and also indications for deeply-sourced fluid migration. We have used the seismic data, together with previously published age constraints, to identify and map key stratigraphic horizons from the ancient subduction margin (on the southeast), through the sedimentary basin, and up onto the modern subduction margin (on the northwest). We have also used BSRs to map the extent of the gas hydrate system throughout the basin. These interpretations are being used to construct a 3D geological model of the basin that will be converted to depth using seismic velocities from the available data. The geological model will provide the basis for modelling fluid flow processes through the basin and ultimately to simulate gas hydrate formation using Petromod. We will present the latest results of this project and outline the implications for gas hydrate formation in the Pegasus Basin.

  6. Molecular Genealogy of a Mongol Queen's Family and Her Possible Kinship with Genghis Khan.

    PubMed

    Lkhagvasuren, Gavaachimed; Shin, Heejin; Lee, Si Eun; Tumen, Dashtseveg; Kim, Jae-Hyun; Kim, Kyung-Yong; Kim, Kijeong; Park, Ae Ja; Lee, Ho Woon; Kim, Mi Jin; Choi, Jaesung; Choi, Jee-Hye; Min, Na Young; Lee, Kwang-Ho

    2016-01-01

    Members of the Mongol imperial family (designated the Golden family) are buried in a secret necropolis; therefore, none of their burial grounds have been found. In 2004, we first discovered 5 graves belonging to the Golden family in Tavan Tolgoi, Eastern Mongolia. To define the genealogy of the 5 bodies and the kinship among them, SNP and/or STR profiles of mitochondria, autosomes, and Y chromosomes were analyzed. Four of the 5 bodies were determined to carry the mitochondrial DNA haplogroup D4, while the fifth carried haplogroup CZ, indicating that this individual had no kinship with the others. Meanwhile, Y-SNP and Y-STR profiles indicate that the males examined belonged to the R1b-M343 haplogroup. Thus, their East Asian D4 or CZ matrilineal and West Eurasian R1b-M343 patrilineal origins reveal genealogical admixture between Caucasoid and Mongoloid ethnic groups, despite a Mongoloid physical appearance. In addition, Y chromosomal and autosomal STR profiles revealed that the four D4-carrying bodies bore the relationship of either mother and three sons or four full siblings with almost the same probability. Moreover, the geographical distribution of R1b-M343-carrying modern-day individuals demonstrates that descendants of Tavan Tolgoi bodies today live mainly in Western Eurasia, with a high frequency in the territories of the past Mongol khanates. Here, we propose that Genghis Khan and his family carried Y-haplogroup R1b-M343, which is prevalent in West Eurasia, rather than the Y-haplogroup C3c-M48, which is prevalent in Asia and which is widely accepted to be present in the family members of Genghis Khan. Additionally, Tavan Tolgoi bodies may have been the product of marriages between the lineage of Genghis Khan's Borjigin clan and the lineage of either the Ongud or Hongirad clans, indicating that these individuals were members of Genghis Khan's immediate family or his close relatives. PMID:27627454

  7. Biodiversity and importance of floating weeds of Dara Ismail, Khan District of KPK, Pakistan.

    PubMed

    Marwat, Sarfaraz Khan; Khan, Mir Ajab; Fazal-ur-Rehman; Ahmad, Mushtaq; Zafar, Muhammad

    2011-01-01

    The present paper is based on the results of taxonomic research work conducted in Dera Ismail Khan District of KPK, Pakistan, during 2005 - 2007. The area was extensively surveyed in order to collect floating aquatic weeds. From the study area 11 floating aquatic weed species belonging to 9 genera and 9 families were collected and identified in the light of available literature. These plants include Bryophytes: 1 species, Ricciocarpus natans (L.) Corda; Pteridophytes: 2 species, Azolla pinnata R.Br. and Marselia quadrifolia L., and Spermatophytes: 8 species, Lemna aequinoctialis Welw., L. gibba L., Marselia quadrifoliata L. Nelumbo nucifera Gaerth., Nymphoides cristata (Roxb.) O. Ketze. Nymphoides indica (L.) Kuntze:, Pistia stratiotes L. Potamogeton nodosus Poiret and Spirodela polyrrhiza (L.) Schleid. Floating weeds on one hand cause serious problems and on the other hand they are used for various purposes. Data inventory consists of botanical name, family, major group, habit and habitat, flowering period, availability, distribution in D.I.Khan, Pakistan and world, beneficial and harmful effects. Key to the floating aquatic species of the area was developed for easy and correct identification and differentiation. PMID:22754062

  8. Slope gradient and lithology as controls on the initiation of submarine slope gullies; Insights from the North Carnarvon Basin, Offshore NW Australia

    NASA Astrophysics Data System (ADS)

    Prélat, Amandine; Pankhania, Shyam S.; Jackson, Christopher A.-L.; Hodgson, David M.

    2015-11-01

    Slope-confined submarine gullies are present on many continental margins, yet the controls on their initiation and demise are poorly understood because modern or recently active systems are rarely if ever monitored, and exhumed systems, typically formed in very fine-grained successions, are poorly preserved at outcrop. We use 3D seismic reflection and borehole data from offshore NW Australia to investigate long-term (~ 40 Myr) variations in the geomorphology of Eocene-to-Miocene gullies that developed in mixed carbonate-clastic clinothems. Through time, clinoform slope gradient increases from 1.6° to 3.2°, with gullies forming when the clinoform slope exceeds 2.5°. After their inception, gullies increase in width (from 350 m to 770 m) and depth (from 37 m to 60 m). Slope steepening appears to coincide with a change from poorly cemented, fine-grained carbonate to better-cemented, coarse-grained carbonate, implying a secondary, lithological control on slope dip and, ultimately, gully formation.

  9. Effective medium modeling of gas hydrate-filled fractures using the sonic log in the Krishna-Godavari basin, offshore eastern India

    NASA Astrophysics Data System (ADS)

    Ghosh, Ranjana; Sain, Kalachand; Ojha, Maheswar

    2010-06-01

    Indian National Gas Hydrate Program Expedition 01 has established that clay-rich marine sediment from the Krishna-Godavari (KG) basin in the eastern Indian margin hosts one of the richest gas hydrate deposits in the world. Resistivity at-bit images and pressure cores reveal that the gas hydrate morphology in clay-rich sediment varies from complex vein structures (grain displacing) to invisible pore filling. Existing rock physics models, which relate acoustic data to in situ gas hydrate concentrations, generally assume isotropic pore-filling gas hydrate, which yields misleading concentration estimates for fractured fine-grained sediments. The anisotropic KG basin sediment presents additional complications. Here we apply differential effective medium theory to incorporate grain-displacing morphologies by which gas hydrate is included as vertical ellipsoids with aspect ratios ranging from those of thin veins up to those of nodules in an elastic anisotropic background. We have estimated gas hydrate concentrations from sonic velocities at hole 10D in the KG basin considering three basic gas hydrate morphologies: (i) pore filling, (ii) grain displacing, and (iii) a combination of grain displacing and pore filling. Average gas hydrate saturations for these three cases are 35-42%, 27-30%, and 33-41% of the total porosity, respectively, in the depth range 60-140 m below seafloor (mbsf). Saturation is highest at ˜67 mbsf for any morphology but the values differ between morphologies. For the pore-filling morphology, the maximum gas hydrate saturation of 56% is 18-22% higher than the grain-displacing morphology and 2-9% higher than the combined morphology. Estimates differ by ±6% of the sediment volume with rotations of gas hydrate veins from vertical to horizontal.

  10. The School Improvement Programme of the Aga Khan Education Service, Kenya at Kisumu, Western Kenya: Evaluation Report.

    ERIC Educational Resources Information Center

    Capper, Joanne; Nderitu, Shelomith; Ogula, Paul

    This evaluation study was conducted at the behest of the Aga Khan Foundation (AKF) and the Institute for Policy Reform (IPR), working under contract with United States Agency for International Development. AKF's primary concern was to evaluate the effectiveness, cost-effectiveness, and the likelihood of sustainability of the School Improvement…

  11. 76 FR 42159 - Lifting of Sanctions on Person Associated With the A.Q. Khan Nuclear Procurement Network

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-18

    ... were first imposed on January 16, 2009 (see 74 FR 3126, Jan 16, 2009; Public Notice 6486). Dated: July... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF STATE Lifting of Sanctions on Person Associated With the A.Q. Khan Nuclear Procurement Network AGENCY: Bureau...

  12. Epidemiological survey of the prevalence of parasites among children in Khan Younis governorate, Palestine.

    PubMed

    Astal, Z

    2004-12-01

    The prevalence of intestinal parasites was determined for 1,370 children in Khan Younis Governorate, Gaza Strip. The age of the children ranged from 6 to 11 years. For stool samples, inspection, direct smear microscopy, flotation and sedimentation techniques were used. The general prevalence of intestinal parasites was 34.2%. Different types of intestinal parasites were detected during this survey: Ascaris lumbricoides seemed to be the most common parasite (12.8%), whereas Giardia lamblia had a prevalence of 8.0%, Entamoeba histolytica 7.0%, Entamoeba coli 3.6%, Trichuris trichiura 1.6% and Hymenolepis nana 1.0%. The prevalence of enterobiasis was determined using a scotch tape preparation. A total of 20.9% of the children examined were infected and there was sex variation in the prevalence of enterobiasis. PMID:15517386

  13. Glacistore: Understanding Late Cenozoic Glaciation and Basin Processes for the Development of Secure Large Scale Offshore CO2 Storage (North Sea).

    NASA Astrophysics Data System (ADS)

    Stewart, H. A.; Barrio, M.; Akhurst, M.; Aagaard, P.; Alcalde, J.; Bauer, A.; Bradwell, T.; Cavanagh, A.; Faleide, J. I.; Furre, A. K.; Haszeldine, S.; Hjelstuen, B. O.; Holloway, S.; Johansen, H.; Johnson, G.; Kuerschner, W.; Mondol, N. H.; Querendez, E.; Ringrose, P. S.; Sejrup, H. P.; Stewart, M.; Stoddart, D.; Wilkinson, M.; Zalmstra, H.

    2014-12-01

    The sedimentary strata of the North Sea Basin (NSB) record the glacial and interglacial history of environmental change in the Northern Hemisphere, and are a proposed location for the engineered storage of carbon dioxide (CO2) captured from power plant and industrial sources to reduce greenhouse gas emissions. These aspects interact in the geomechanical and fluid flow domain, as ice sheet dynamics change the properties of potential seal and reservoir rocks that are the prospective geological storage strata for much of Europe's captured CO2. The intensification of the global glacial-interglacial cycle at the onset of the Pleistocene (2.5-2.7 Ma) was a critical tipping-point in Earth's recent climate history. The increased severity of glaciations at the Plio-Pleistocene boundary triggered the first development of large-scale continental ice sheets in the Northern Hemisphere. The central part of the NSB preserves a unique history of the depositional record spanning at least the last 3 Ma, which also forms the overburden and seal to the underlying CO2 reservoirs. There is good evidence that these ice sheets created strong feedback loops that subsequently affected the evolution of the Quaternary climate system through complex ocean-atmosphere-cryosphere linkages. Understanding NSB dynamics, including the role of fluids in controlling compaction, cementation, and diagenetic processes in shale-dominated basins, is essential for CO2 storage site characterisation to increase understanding and confidence in secure storage. An increased understanding of the overlying sequence will inform quantitative predictions of the performance of prospective CO2 storage sites in glaciated areas in Europe and worldwide; to include improved resolution of glacial cycles (depositional and chronological framework), characterise pore fluids, flow properties of glacial landforms within the sequence (e.g. tunnel valleys) and the geomechanical effects (quantify compaction, rock stiffness, strength

  14. Where the offshore search for oil and gas is headed

    SciTech Connect

    King, R.E.

    1980-10-01

    This overview of the world's potential offshore oil and gas frontiers points out that although solutions to technical and political problems have opened up some promising areas for exploration, many key frontier basins have yet to be explored by modern technology. Long-standing disputes between bordering countries over offshore rights have deterred exploration activities in the Malvinas basin off Argentina and in the Gulf of Venezuela. Political problems have also slowed activity in the US Atlantic offshore, where Mesozoic reef trends may be related to Mexico's large oil fields. In Canada's Labrador Sea and Grand Banks, the problems are largely operational because of the inclement weather and threatening icebergs. The thick sediments off northern Norway remain untapped due to the deep water, Arctic conditions, and boundary disputes with the USSR. The main areas of active exploration are the Gulf of Thailand-Penyu-Natuna basin in Southeast Asia and Ireland's Porcupine Bight basin.

  15. Tectono-sedimentary events and geodynamic evolution of the Mesozoic and Cenozoic basins of the Alpine Margin, Gulf of Tunis, north-eastern Tunisia offshore

    NASA Astrophysics Data System (ADS)

    Melki, Fetheddine; Zouaghi, Taher; Chelbi, Mohamed Ben; Bédir, Mourad; Zargouni, Fouad

    2010-09-01

    The structural pattern, tectono-sedimentary framework and geodynamic evolution for Mesozoic and Cenozoic deep structures of the Gulf of Tunis (north-eastern Tunisia) are proposed using petroleum well data and a 2-D seismic interpretation. The structural system of the study area is marked by two sets of faults that control the Mesozoic subsidence and inversions during the Paleogene and Neogene times: (i) a NE-SW striking set associated with folds and faults, which have a reverse component; and (ii) a NW-SE striking set active during the Tertiary extension episodes and delineating grabens and subsiding synclines. In order to better characterize the tectono-sedimentary evolution of the Gulf of Tunis structures, seismic data interpretations are compared to stratigraphic and structural data from wells and neighbouring outcrops. The Atlas and external Tell belonged to the southernmost Tethyan margin record a geodynamic evolution including: (i) rifting periods of subsidence and Tethyan oceanic accretions from Triassic until Early Cretaceous: we recognized high subsiding zones (Raja and Carthage domains), less subsiding zones (Gamart domain) and a completely emerged area (Raouad domain); (ii) compressive events during the Cenozoic with relaxation periods of the Oligocene-Aquitanian and Messinian-Early Pliocene. The NW-SE Late Eocene and Tortonian compressive events caused local inversions with sealed and eroded folded structures. During Middle to Late Miocene and Early Pliocene, we have identified depocentre structures corresponding to half-grabens and synclines in the Carthage and Karkouane domains. The north-south contractional events at the end of Early Pliocene and Late Pliocene periods are associated with significant inversion of subsidence and synsedimentary folded structures. Structuring and major tectonic events, recognized in the Gulf of Tunis, are linked to the common geodynamic evolution of the north African and western Mediterranean basins.

  16. Google, Mathletics and Khan Academy: students' self-initiated use of online mathematical resources

    NASA Astrophysics Data System (ADS)

    Muir, Tracey

    2014-12-01

    Today's students increasingly engage in online environments, with ready access to digital resources and mobile technologies. While much of this activity is socially motivated, the internet is also a source of knowledge for students and frequently accessed for school assignments, projects and assessment purposes. As mathematics continues to be an area in which many students experience difficulties, it is not surprising that a recent Google search produced 57,600,000 results for `help with mathematics'. Current research, however, is limited in terms of documenting students' use of such resources, particularly when they are self-initiated and often accessed in an out of classroom environment. This paper reports on a study that investigated the use of mathematical online resources accessed by students in Grades 5-9, with a particular focus on evaluating the effectiveness of Khan Academy, an online tutorial site. Data collected through surveys and interviews showed that while students did access online sites, particularly in the later years of schooling, they varied in both their reasons for doing so and their perceptions of how useful these sites were. The findings add to the limited research in this area and have practical implications for students and teachers, including the potential to challenge the traditional role of the teacher.

  17. Students’ perception of educational environment at Aga Khan University Medical College, Karachi, Pakistan

    PubMed Central

    Rehman, Rehana; Ghias, Kulsoom; Fatima, Syeda Sadia; Hussain, Mehwish; Alam, Faiza

    2016-01-01

    Objective: To assess educational environment in Aga Khan University Medical College (AKUMC) by Dundee Ready Educational Environmental Measure (DREEM) scale. Methods: A cross-sectional survey of students at the AKUMC with simple random sampling was carried out from June 2014 till March 2015. Responses in five subscales were used to calculate DREEM scores. Results: The average DREEM score was 125.77±16.8 with a reliability of 91.3%. With regards to subscales, on the 12-item students’ perceptions of learning (PoL) subscale, the maximum score was 48; 11 items of students’ perceptions of teachers (PoT) had a maximum score of 44; students’ academic self-perceptions (ASP) identified by 8 items showed maximum score of 32; students’ perceptions of atmosphere (PoA) with 12 items obtained maximum score 48 and students’ social self-perceptions (SSP) subscale of 7 items had a maximum score of 28. Conclusion: Students perceived a positive learning environment at AKUMC Karachi. PMID:27375721

  18. Natural radioactivity, dose assessment and uranium uptake by agricultural crops at Khan Al-Zabeeb, Jordan.

    PubMed

    Al-Kharouf, Samer J; Al-Hamarneh, Ibrahim F; Dababneh, Munir

    2008-07-01

    Khan Al-Zabeeb, an irrigated cultivated area lies above a superficial uranium deposits, is regularly used to produce vegetables and fruits consumed by the public. Both soil and plant samples collected from the study area were investigated for their natural radioactivity to determine the uranium uptake by crops and hence to estimate the effective dose equivalent to human consumption. Concentrations of (238)U, (235)U, (232)Th, (226)Ra, (222)Rn, (137)Cs and (40)K in nine soil profiles were measured by gamma-ray spectrometry whereas watermelon and zucchini crops were analyzed for their uranium content by means of alpha spectrometry after radiochemical separation. Correlations between measured radionuclides were made and their activity ratios were determined to evaluate their geochemical behavior in the soil profiles. Calculated soil-plant transfer factors indicate that the green parts (leaves, stems and roots) of the studied crops tend to accumulate uranium about two orders of magnitude higher than the fruits. The maximum dose from ingestion of 1 kg of watermelon pulp was estimated to be 3.1 and 4.7 nSv y(-1) for (238)U and (234)U, respectively. Estimations of the annual effective dose equivalent due to external exposure showed extremely low values. Radium equivalent activity and external hazard index were seen to exceed the permissible limits of 370 Bq kg(-1) and 1, respectively. PMID:18359539

  19. Applications for concrete offshore

    SciTech Connect

    Not Available

    1982-01-01

    The report collects and summarizes the various proposals for development offshore which have in common the use of concrete as the main structural material, and where possible, indicates their relative feasibility. A study encompassing such diverse schemes as offshore windmills, concrete LNG carriers, hydrocarbon production platforms and floating airports cannot be completely exhaustive on each subject, so references to sources of further information have been given wherever possible. Details of individual projects and proposals are included for Power plants, Hydrocarbon production platforms, Concrete ships, Storage systems and industrial plants, Subsea systems, Offshore islands, Coastal works and Other concrete structures.

  20. Session: Offshore wind

    SciTech Connect

    Gaarde, Jette; Ram, Bonnie

    2004-09-01

    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.

  1. Norwegian Offshore Stratigraphic Lexicon (NORLEX)

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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.

  2. Exploration and development offshore southern Vietnam

    SciTech Connect

    Ferguson, A.M. )

    1996-01-01

    In Vietnam, the major focus of the oil and gas industry is on the Nam Con Son and Cuu Long Basins in the southern offshore area. Major licensing first occurred here in the early 1970s. Some exploration was also undertaken by foreign companies in the early 1980s. In 1981, the Soviet Union undertook to assist Vietnam with the development of oil and gas. Vietsovpetro, a joint venture between the then Soviet Oil and Gas Ministry and the Vietnam Oil and Gas Corporation was formed. Most of Vietsovpetro's efforts have been to develop the Bach Ho field in the Cuu Long Basin. This now produces [approximately]130000 bopd. The most recent large scale licensing round occurred in 1992, and, at present, there are over thirty foreign companies active in these Basins' blocks . The first phase of exploration is ending and successes in the Nam Con Son Basin include the BP-led Lan Tay/Lan Do gas discoveries and Pedco's gas discoveries. Mitsubishi's and Petronas' oil discoveries in the Cuu Long Basin have attracted much attention also. The Dai Hung oil field (BHP-operated) has been producing since late 1994. Certain blocks are being appraised, and exploration work is also continuing. Areas of the Cuu Long Basin that were part of Vietsovpetro's acreage, but which may soon be re-licensed, have generated keen interest. The presence of an active upstream industry - exploring, appraising, developing and producing - indicates the emergence of Vietnam as an important East Asian oil and gas player.

  3. Medicinal uses of honey (Quranic medicine) and its bee flora from Dera Ismail Khan District, KPK, Pakistan.

    PubMed

    Marwat, Sarfaraz Khan; Khan, Muhammad Aslam; Rehman, Fazalur; Khan, Kaleemullah

    2013-03-01

    This study was carried out during 2005-2008 to identify existing plant species visited by workers of honeybees for nectar and pollen collection in Dera Ismail Khan (D.I.Khan) District, Pakistan. The honeybee species investigated in the area were, rock bee (Apis dorsata F.), little bee (A. florea F.) and European honeybee (A. mellifera L.). A detailed list of 86 plant species both wild and cultivated was prepared, out of which 12 species, Phulai (Acacia modesta Wall.), Sarsoon (Brassica campestris L.), Kaghzi nimboo (Citrus aurantifolia L.), Khatta (C. medica L.), Malta (C. sinensis (L.) Osbeck.), Shisham (Dalbergia sissoo Roxb.), Date (Phoenix dactylifera L.), Barseen (Trifolium alexandrianum L.), Shaftal (T. resupinatum L), Makai (Zea mays L.), Ber (Zizyphus mauritiana Lam.) and Jher beri (Z. numularia (Burm. f.) Wight & Arn.,) were found as major sources (table 1) for the production of surplus honey in a year at different localities in the District. Among the minor sources various plant species were included (table 2). These plants fill the flowering gaps between the major sources in various parts of the year and help in continuous supply of food to honey bees. PMID:23455201

  4. The Offshore East African Rift System

    NASA Astrophysics Data System (ADS)

    Franke, D.; Klimke, J.; Jokat, W.; Stollhofen, H.; Mahanjane, S.

    2014-12-01

    Numerous studies have addressed various aspects of the East African Rift system but surprisingly few on the offshore continuation of the south-eastern branch of the rift into the Mozambique Channel. The most prominent article has been published almost 30 years ago by Mougenot et al. (1986) and is based on vintage seismic data. Several studies investigating earthquakes and plate motions from GPS measurements reveal recent deformation along the offshore branch of the East African Rift system. Slip vectors from earthquakes data in Mozambique's offshore basins show a consistent NE direction. Fault plane solutions reveal ~ E-W extensional failure with focal depth clustering around 19 km and 40 km, respectively. Here, we present new evidence for neotectonic deformation derived from modern seismic reflection data and supported by additional geophysical data. The modern rift system obviously reactivates structures from the disintegration of eastern Gondwana. During the Jurassic/Cretaceous opening of the Somali and Mozambique Basins, Madagascar moved southwards along a major shear zone, to its present position. Since the Miocene, parts of the shear zone became reactivated and structurally overprinted by the East African rift system. The Kerimbas Graben offshore northern Mozambique is the most prominent manifestation of recent extensional deformation. Bathymetry data shows that it deepens northwards, with approximately 700 m downthrown on the eastern shoulder. The graben can be subdivided into four subbasins by crosscutting structural lineaments with a NW-SE trend. Together with the N-S striking graben-bounding faults, this resembles a conjugate fault system. In seismic reflection data normal faulting is distinct not only at the earthquake epicenters. The faults cut through the sedimentary successions and typically reach the seafloor, indicating ongoing recent deformation. Reference: Mougenot, D., Recq, M., Virlogeux, P., and Lepvrier, C., 1986, Seaward extension of the East

  5. Offshore Benin, a classic passive margin

    SciTech Connect

    Mathalone, J.M.P. )

    1991-03-01

    Offshore Benin comprises a narrow east-west continental shelf, some 30 km wide. A sharp shelf break running parallel to the coast borders the shelf, whereupon water depths rapidly increase to over 7000 ft. The area lies within the Dahomey Embayment, one of a series of Cretaceous and younger basins lining the coast of Africa that owe their inception to the Late Mesozoic break-up of the Gondwanaland Continent. The basin extends some 100 km inland, but sedimentary section is thin onshore compared to a maximum of 20,000 ft of sediment offshore. Initial sedimentation in this basin was of Neocomian alluvial and lacustrine clastics. These were deposited in east-west-trending narrow half-grabens associated with the initial break up of the South American and African continents. They are covered unconformably by more extensive Albian and Cenomanian transgressive clastics and shallow marine Turonian sandstones which are the main reservoir at Seme, Benin's only oilfield. The Senonian section offshore comprises passive margin deep sea clastic sediments prograding southwards. Very large proximal deep sea channels up to 2500 ft thick are developed in this interval. These channels are associated with excellent petroleum source rocks, averaging 4-5% oil-prone organic carbon, and form the main exploration target in the area when configured in a trap morphology. Seismic data quality is excellent in the region allowing detailed examination of the relationships between the rifted section and later units. In addition, these data illustrate clearly both internal and external morphology of the Senonian proximal deep sea channels.

  6. Drilling and producing offshore

    SciTech Connect

    Hall, R.S.

    1983-01-01

    Hall and his team of authors share technically detailed state-of-the-art designs, equipment and techniques, focusing on fixed-platform operations. This book provides explicit data on offshore equipment and procedures. Contents: Development drilling structures -- template, concrete gravity, and other platforms; Development drilling systems -- through-the-leg drilling, floating drilling, tension-leg platform drilling, template utilization, and mud-line casing suspension and casing support systems; Completion systems -- platform completions, through-the-leg completions, tension-leg completions, multiwell subsea completions, and subsea satellite completion systems; Production control -- wellhead control systems and subsea production control systems; Offshore oil-field diving operations and equipment -- commercial diving, history of diving, international offshore oil-field diving, physiological constraints in diving, diving capabilities and equipment, future trends.

  7. Energy from Offshore Wind: Preprint

    SciTech Connect

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

    2006-02-01

    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.

  8. Tectonic framework of Turkish sedimentary basins

    SciTech Connect

    Yilmaz, P.O. )

    1988-08-01

    Turkey's exploration potential primarily exists in seven onshore (Southeast Turkey platform, Tauride platform, Pontide platform, East Anatolian platform, Interior, Trace, and Adana) basins and four offshore (Black Sea, Marmara Sea, Aegean Sea, and Mediterranean Sea) regional basins formed during the Mesozoic and Tertiary. The Mesozoic basins are the onshore basins: Southeast Turkey, Tauride, Pontide, East Anatolian, and Interior basins. Due to their common tectonic heritage, the southeast Turkey and Tauride basins have similar source rocks, structural growth, trap size, and structural styles. In the north, another Mesozoic basin, the Pontide platform, has a much more complex history and very little in common with the southerly basins. The Pontide has two distinct parts; the west has Paleozoic continental basement and the east is underlain by island-arc basement of Jurassic age. The plays are in the upper Mesozoic rocks in the west Pontide. The remaining Mesozoic basins of the onshore Interior and East Anatolian basins are poorly known and very complex. Their source, reservoir, and seal are not clearly defined. The basins formed during several orogenic phases in mesozoic and Tertiary. The Cenozoic basins are the onshore Thrace and Adana basins, and all offshore regional basins formed during Miocene extension. Further complicating the onshore basins evolution is the superposition of Cenozoic basins and Mesozoic basins. The Thrace basin in the northwest and Adana basin in the south both originate from Tertiary extension over Tethyan basement and result in a similar source, reservoir, and seal. Local strike-slip movement along the North Anatolian fault modifies the Thrace basin structures, influencing its hydrocarbon potential.

  9. Offshore rectenna feasbility

    NASA Technical Reports Server (NTRS)

    Freeman, J. W.; Hervey, D.; Glaser, P.

    1980-01-01

    A preliminary study of the feasibility and cost of an offshore rectenna to serve the upper metropolitan east coast was performed. A candidate site at which to build a 5 GW rectenna was selected on the basis of proximity to load centers, avoidance of shipping lanes, sea floor terrain, and relocated conditions. Several types of support structures were selected for study based initially on the reference system rectenna concept of a wire mesh ground screen and dipoles each with its own rectifier and filter circuits. Possible secondary uses of an offshore rectenna were examined and are evaluated.

  10. Offshore wave energy experiment

    SciTech Connect

    Nielsen, K.; Scholten, N.C.; Soerensen, K.A. |

    1995-12-31

    This article describes the second phase of the off-shore wave energy experiment, taking place in the Danish part of the North Sea near Hanstholm. The wave power converter is a scale model consisting of a float 2.5 meter in diameter connected by rope to a seabed mounted piston pump installed on 25 meter deep water 2,5 km offshore. The structure, installation procedure results and experience gained during the test period will be presented and compared to calculations based on a computer model.

  11. Cyrtodactylus samroiyot, a new limestone-dwelling Bent-toed Gecko (Squamata: Gekkonidae) from Prachuap Khiri Khan Province, peninsular Thailand.

    PubMed

    Pauwels, Olivier S G; Sumontha, Montri

    2014-01-01

    We describe Cyrtodactylus samroiyot sp. nov. from a limestone relief in Sam Roi Yot District, Prachuap Khiri Khan Province, peninsular Thailand. It is characterized by a maximal known SVL of 66.9 mm; 17-18 longitudinal rows of dorsal tubercles; 33-34 longitudinal rows of ventrals across the abdomen between the ventrolateral skin folds; a continuous series of seven precloacal pores in males (six shallow precloacal pits in females); a series of slightly enlarged, poreless and pitless femoral scales; no precloacal groove nor depression; median row of transversely enlarged subcaudal scales; a complete nuchal loop; and a dorsal pattern consisting of three long dark brown bands, one above shoulders and two above abdomen.  PMID:24869842

  12. Foam pigs solve pipe cleaning problems offshore Brazil

    SciTech Connect

    Lima, P.C.R.; Neto, S.J.A.

    1995-10-02

    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.

  13. Offshore Wind Energy Systems

    ERIC Educational Resources Information Center

    Musgrove, P.

    1978-01-01

    Explores the possibility of installing offshore windmills to provide electricity and to save fuel for the United Kingdom. Favors their deployment in clusters to facilitate supervision and minimize cost. Discusses the power output and the cost involved and urges their quick development. (GA)

  14. Offshore Wind Research (Fact Sheet)

    SciTech Connect

    Not Available

    2011-10-01

    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.

  15. Offshore space center (offshore launch site)

    SciTech Connect

    Harvey, D.G.

    1980-07-01

    Any activity requiring the development of the HLLV can benefit by operations from an offshore space center (OSC) since operating near the equator provides a twenty percent increase in payload in an ecliptic plan orbit. Some OSC concepts considered include a moored floating (semisubmersible) design, a stationary design supported by fixed piles, and a combination of these two. The facility supports: a 15,000 foot long, 300 foot wide runway, designed to accommodate a two staged winged launch vehicle, with a one million pound payload capacity to low earth orbit, an industrial area for HLLV maintenance, an airport terminal, control and operation center, and observation tower, liquid hydrogen and liquid oxygen production and storage, and fuel storage platforms, a power generation station, docks with an unloading area, two separate launch sites, and living accommodations for 10,000 people. Potential sites include the Paramount Seamount in the Pacific Ocean off the north coast of South America. Cost estimates are considered.

  16. Offshore Space Center (offshore launch site)

    NASA Technical Reports Server (NTRS)

    Harvey, D. G.

    1980-01-01

    Any activity requiring the development of the HLLV can benefit by operations from an offshore space center (OSC) since operating near the equator provides a twenty percent increase in payload in an ecliptic plan orbit. Some OSC concepts considered include a moored floating (semisubmersible) design, a stationary design supported by fixed piles, and a combination of these two. The facility supports: a 15,000 foot long, 300 foot wide runway, designed to accommodate a two staged winged launch vehicle, with a one million pound payload capacity to low earth orbit; an industrial area for HLLV maintenance; an airport terminal, control and operation center, and observation tower; liquid hydrogen and liquid oxygen production and storage, and fuel storage platforms; a power generation station, docks with an unloading area; two separate launch sites; and living accommodations for 10,000 people. Potential sites include the Paramount Seamount in the Pacific Ocean off the north coast of South America. Cost estimates are considered.

  17. Industry decries sharp decline in U. S. offshore activity

    SciTech Connect

    Not Available

    1992-05-11

    Roadblocks to offshore activity in the U.S. drew much of the spotlight at the 24th Offshore Technology Conference last week in Houston. Among OTC highlights included in this paper are: Two panels reviewed how federal leasing moratoriums and regulatory restrictions are reining U.S. offshore development. Conoco Inc.'s manager of exploration and development in Russia detailed the allure of giant and supergiant fields in the Commonwealth of Independent States and reviewed the status of the company's efforts to negotiate E and D deals with Russian partners. Minerals Management Service officials reviewed environmental challenges facing operators on the U.S. Outer Continental Shelf and new MMS inspection strategies in the Gulf of Mexico. The 1992 OTC Distinguished Achievement Award for companies went to Brazil's Petroleo Brasileiro SA for deepwater development records set with the 3 Marlim well in the Campos basin off Brazil.

  18. Evidence of offshore lake trout reproduction in Lake Huron

    USGS Publications Warehouse

    DeSorcie, Timothy J.; Bowen, Charles A., II

    2003-01-01

    Six Fathom Bank-Yankee Reef, an offshore reef complex, was an historically important spawning area believed to represent some of the best habitat for the rehabilitation of lake trout Salvelinus namaycush in Lake Huron. Since 1986, lake trout have been stocked on these offshore reefs to reestablish self-sustaining populations. We sampled with beam trawls to determine the abundance of naturally reproduced age-0 lake trout on these offshore reefs during May-July in 1994-1998 and 2000-2002. In total, 123 naturally reproduced lake trout fry were caught at Six Fathom Bank, and 2 naturally reproduced lake trout fry were caught at nearby Yankee Reef. Our findings suggest that this region of Lake Huron contains suitable habitat for lake trout spawning and offers hope that lake trout rehabilitation can be achieved in the main basin of Lake Huron.

  19. Exploration and development offshore southern Vietnam

    SciTech Connect

    Ferguson, A.M.

    1996-12-31

    In Vietnam, the major focus of the oil and gas industry is on the Nam Con Son and Cuu Long Basins in the southern offshore area. Major licensing first occurred here in the early 1970s. Some exploration was also undertaken by foreign companies in the early 1980s. In 1981, the Soviet Union undertook to assist Vietnam with the development of oil and gas. Vietsovpetro, a joint venture between the then Soviet Oil and Gas Ministry and the Vietnam Oil and Gas Corporation was formed. Most of Vietsovpetro`s efforts have been to develop the Bach Ho field in the Cuu Long Basin. This now produces {approximately}130000 bopd. The most recent large scale licensing round occurred in 1992, and, at present, there are over thirty foreign companies active in these Basins` blocks . The first phase of exploration is ending and successes in the Nam Con Son Basin include the BP-led Lan Tay/Lan Do gas discoveries and Pedco`s gas discoveries. Mitsubishi`s and Petronas` oil discoveries in the Cuu Long Basin have attracted much attention also. The Dai Hung oil field (BHP-operated) has been producing since late 1994. Certain blocks are being appraised, and exploration work is also continuing. Areas of the Cuu Long Basin that were part of Vietsovpetro`s acreage, but which may soon be re-licensed, have generated keen interest. The presence of an active upstream industry - exploring, appraising, developing and producing - indicates the emergence of Vietnam as an important East Asian oil and gas player.

  20. Arctic offshore platform

    SciTech Connect

    Bhula, D.N.

    1984-01-24

    An offshore structure is disclosed for use in drilling and producing wells in arctic regions having a conical shaped lower portion that extends above the surface of the water and a cylindrical upper section. The conical portion is provided with a controlled stiffness outer surface for withstanding the loads produced by ice striking the structure. The stiffness properties of the outer shell and flexible members are designed to distribute the load and avoid high local loads on the inner parts of the structure.

  1. Stratigraphic modeling of sedimentary basins

    SciTech Connect

    Aigner, T. ); Lawrence, D.T. )

    1990-11-01

    A two-dimensional stratigraphic forward model has been successfully applied and calibrated in clastic, carbonate, and mixed clastic/carbonate regimes. Primary input parameters are subsidence, sea level, volume of clastics, and carbonate growth potential. Program output includes sequence geometries, facies distribution lithology distribution, chronostratigraphic plots, burial history plots, thermal and maturity histories, and crossplots. The program may be used to predict reservoir distribution, to constrain interpretations of well and seismic data, to rapidly test exploration scenarios in frontier basins, and to evaluate the fundamental controls on observed basin stratigraphy. Applications to data sets from Main Pass (US Gulf Coast), Offshore Sarawak (Malaysia), Rub'al Khali basin (Oman), Paris basin (France), and Baltimore Canyon (US East Coast) demonstrate that the program can be used to simulate stratigraphy on a basin-wide scale as well as on the scale of individual prospects.

  2. Combining rainfall data from rain gauges and TRMM in hydrological modelling of Laotian data-sparse basins

    NASA Astrophysics Data System (ADS)

    Liu, Xing; Liu, Fa Ming; Wang, Xiao Xia; Li, Xiao Dong; Fan, Yu Yan; Cai, Shi Xiang; Ao, Tian Qi

    2015-09-01

    At present, prediction of streamflow simulation in data-sparse basins of the South East Asia is a challenging task due to the absence of reliable ground-based rainfall information, while satellite-based rainfall estimates are immensely useful to improve our understanding of spatio-temporal variation of rainfall, particularly for data-sparse basins. In this study the TRMM 3B42 V7 and its bias-corrected data were, respectively, used to drive a physically based distributed hydrological model BTOPMC to perform daily streamflow simulations in Nam Khan River and Nam Like River basins during the years from 2000 to 2004 so as to investigate the potential use of the TRMM in complementing rain gauge data in hydrological modelling of data-sparse basins. The results show that although larger difference exists in the high streamflow process and the low streamflow process, the daily simulations fed with TRMM precipitation data could basically reflect the daily streamflow processes at the four stations and determine the time to peak. Furthermore, the calibrated parameters in the Nam Khan River basin are more suitable than that in the Nam Like River basin. By comparing the two precipitation data, it indicates that the integration of TRMM precipitation data and rain gauge data have a promising prospect on the hydrological process simulation in data-sparse basin.

  3. Fluoride enrichment in groundwater of semi-arid urban area: Khan Younis City, southern Gaza Strip (Palestine)

    NASA Astrophysics Data System (ADS)

    Abu Jabal, Mohamed Shaban; Abustan, Ismail; Rozaimy, Mohd Remy; Al-Najar, Hussam

    2014-12-01

    The aim of this study is to determine fluoride enhancement in the groundwater of semi-arid urban area of Khan Younis City, southern Gaza Strip. Physicochemical data for a total of 200 groundwater samples were analyzed. The fluoride concentrations were varied from 0.3 to 6.45 mg/L with average value of 2.87 mg/L. Correlations between fluorides with other measured ions were relatively observed, negative correlation with calcium and the positive correlation with pH, bicarbonate and sodium increase the dissolution/solubility of fluoride bearing minerals, leading to fluoride leaching into the groundwater. Fluoride enrichment in the groundwater of the area is due to water hydrochemistry, mineral-water interaction (mainly calcite and fluorite), fluorite resulted from fluorapatite dissolution. The saturation indexes evaluation indicated that 42% of the samples are over saturated with respect to calcite and 35.5% under saturated with respect to fluorite, while 40.5% approached equilibrium with respect to both calcite and fluorite. At fluoride concentrations of less than 2.2 mg/L fluorite saturation indexes show under-saturation condition for fluorite and at higher fluoride concentrations show near saturation condition.

  4. Geological history of the west Libyan offshore and adjoining regions

    SciTech Connect

    Benniran, M.M.; Taleb, T.M.; McCrossan, R.G.

    1988-08-01

    The continental margin of the African plate north of Libya is separated from the Saharan platform to the south by a major Variscan fault system running along the coastline. The structural evolution of three sedimentary basins within the margin is discussed. The Jeffara basin, onshore western Libya-southern Tunisia, formed as a right-lateral pull-part late in the Variscan event. When the strike-slip motion ceased in the Late Permian, the basin continued to subside thermally. The Sabratah (Tripolitanian) basin, offshore western Libya-southern Tunisia, and the Benghazi basin in the Sirte rise were both formed as left-lateral pull-aparts in the Late Triassic-Early Jurassic. From the Middle Jurassic to the present they have subsided thermally. Onshore the lower Mesozoic is characterized by continental and nearshore clastics, separated by an evaporite sequence of Late Triassic-Early Jurassic age. Offshore this sequence is thought to grade northward into open marine carbonates. Uplift along the edge of the Saharan platform during the Early Cretaceous sourced coarse clastics, which grade northward into a thick sequence of shallow-water carbonates. Throughout the Late Cretaceous and early Tertiary, high-energy carbonates were deposited around the flanks of the Sabratah basin, grading into deeper-water, fine-grained clastics and carbonates toward the center of the basin. The late Tertiary succession is dominated by clastics derived from the growing Tellian Atlas to the northwest. During the Mesozoic and Tertiary a thick sequence of carbonates was deposited on the Pelagian platform to the north of the Sabratah basin. Periodically the platform was exposed subaerially.

  5. Rift basins in western margin of India and their hydrocarbon prospects with special reference to Kutch basin

    SciTech Connect

    Biswas, S.K.

    1982-10-01

    The western continental margin of India can be classed as a divergent or passive margin. The western continental shelf is an extensive carbonate bank (Bombay offshore basin) passing into clastic sediments on the north and south. Three craton-margin embayed basins-Kutch, Cambay, and Narmada- in the northern part of the shelf, are filled predominantly with clastic sediments. These basins occupy grabens bounded by faults diverging seaward. The grabens were formed by three rift systems along major Precambrian tectonic trends. The rifting developed sequentially from north to south around the Saurashtra horst. Kutch basin was formed in the Early Jurassic, followed by Cambay basin in Early Cretaceous time, and the Narmada in the Late Cretaceous. It appears that these rifting events occurred at successive stages during the northward migration of the Indian plate after its break from Gondwanaland in Late Triassic or Early Jurassic. It is inferred that these rift basins opened up successively as a result of the counterclockwise drift of the Indian craton. Bombay offshore and Cambay are two major oil-producing basins in the western margin. These basins are characterized by high geothermal gradients attributed to the shallowness of the mantle in this region. Oil has not been found in KUtch basin, which is mainly an onshore Mesozoic basin. The basin basin depocenter shifted offshore at the northwestern part of the continental shelf where the shelf is wide.

  6. Reinforced concrete offshore platform

    SciTech Connect

    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

    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.

  7. Assessment of undiscovered conventional oil and gas resources of Bonaparte Basin, Browse Basin, Northwest Shelf, and Gippsland Basin Provinces, Australia, 2011

    USGS Publications Warehouse

    Pollastro, Richard M.; Brownfield, Michael E.; Charpentier, Ronald R.; Cook, Troy A.; Klett, Timothy R.; Kirschbaum, Mark A.; Pitman, Janet K.; Schenk, Christopher J.

    2012-01-01

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated means of 4.7 billion barrels of undiscovered oil and 227 trillion cubic feet of undiscovered natural gas in three major offshore petroleum basins of northwest Australia and in the Gippsland Basin of southeast Australia.

  8. Offshore outlook: the American Arctic

    SciTech Connect

    Jahns, M.O.

    1985-05-01

    Offshore areas in the American Arctic are highlighted and the development of the area is compared with other offshore areas where the required technology is more readily available. Principal areas are shown in which new concepts are being put to practice. Canada's east coast is examined. Several technological trends are reviewed to help operators accelerate the discovery and development of arctic petroleum reserves.

  9. Towers for Offshore Wind Turbines

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

    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

  10. Pioneering offshore excellence

    SciTech Connect

    Kent, R.P.; Grattan, L.

    1996-11-01

    Hibernia Management and Development Company Ltd. (HMDC) was formed in 1990 by a consortium of oil companies to develop their interests in the Hibernia and Avalon reservoirs offshore Newfoundland in a safe and environmentally responsible manner. The reservoirs are located 315km ESE of St. John`s in the North Atlantic. The water depth is about 80m. The entire Hibernia field is estimated to contain more than three billion barrels of oil in place and the owners development plan area is estimated to contain two billion barrels. Recoverable reserves are estimated to be approximately 615 million barrels. The Hibernia reservoir, the principle reservoir, is located at an average depth of 3,700m. HMDC is building a large concrete gravity based structure (GBS) that which will support the platform drilling and processing facilities and living quarters for 280 personnel. In 1997 the platform will be towed to the production site and production will commence late 1997. Oil will be exported by a 2 km long pipeline to an offshore loading system. Dynamically positioned tankers will then take the oil to market. Average daily production is expected to plateau between 125,000 and 135,000 BOPD. It will be the first major development on the east coast of Canada and is located in an area that is prone to pack ice and icebergs.

  11. Offshore production challenged

    SciTech Connect

    Franco, A.

    1983-10-01

    The capability to produce oil fields from under 20,000 ft of water or below the thick and treacherous Arctic icepack are 2 of the breakthroughs that have been brought about by a quietly emerging technology. A scan of announcements by designers, contractors, operators, and manufacturers reveals that substantial research and development efforts are being undertaken to ease the task of bringing to market the energy resources trapped under presently inaccessible locations. As a result, entirely new breeds of permanent or temporary drilling/production systems are evolving, some of which could be scaled down to face still another challenge: the economic exploitation of marginal offshore fields, whose meager reserves do not justify development by conventional means. New offshore systems described include the mobile Arctic drilling system, the mobile concrete island drilling system, the base and independent deck platform, the buoyant tower, the semiflex floating station, the tension leg platform, the big buoy floating cylinder, and the Sea Plex retrievable drilling/production system.

  12. Colloidal origin of colloform-banded textures in the Paleogene low-sulfidation Khan Krum gold deposit, SE Bulgaria

    NASA Astrophysics Data System (ADS)

    Marinova, Irina; Ganev, Valentin; Titorenkova, Rositsa

    2014-01-01

    We studied both colloform-banded macro- and micro-textures as well as the composition of electrum from the epithermal Khan Krum (or Ada Tepe) gold deposit, Bulgaria (5 Mt at 5.1 g/t Au + 2.7 g/t Ag) using optical and electron scanning microscopy, vibration spectroscopy, electron micro-probe analysis, and LA-ICP-MS. The individual textural bands differ in grain size, porosity, quartz-to-adularia ratio, and abundance of electrum, pyrite, and scattered dusty opaque micro-inclusions. The individual macro-bands have formed successively via intermittent fault dilation from episodic hydrothermal pulses, as a result of regional extension and most likely originated from colloidal solutions formed by vigorous boiling during rapid pressure drop and supersaturation with respect to amorphous silica in a closed or quasi-closed hydrothermal system. Electrum is highly concentrated in the finest quartz-adularia colloform micro-bands, which fill joints with widths up to 1-2 mm. We presume that the joints have filled in with more concentrated colloidal solutions than those in the macro-bands, most likely due to extreme boiling of fluids in open or quasi-open hydrothermal system. Electrum in the micro-bands forms transverse dendrite- and chain-like aggregates as well as oval clots along the banding, all of globular morphology. We explain these locations of electrum with reorientation of aggregated electrum globules during plastic deformation of a mixed electrum-silicate gel and in result from the consequent crystallization of silicates. At the same time, electrum is not present in pores and cracks of syneresis, which indicates that it had not been a soluble phase at the time of syneresis, rather colloidal particles. Electrum also forms dense sprinkles of globular morphology deposited in open space on the surfaces of some quartz-adularia bands, due to a condensation of gaseous phase, separated during the boiling of fluids. We found that the electrum-rich quartz-adularia micro

  13. Seismic evidence for hyper-stretched crust and mantle exhumation offshore Vietnam.

    NASA Astrophysics Data System (ADS)

    Savva, D.; Meresse, F.; Pubellier, M.; Chamot-Rooke, N.; Franke, D.; Steuer, S.; Sapin, F.; Auxietre, J. L.

    2012-04-01

    The Phu Khan basin is one of the sub-basins opened during the rifting of the South China Sea during the Eocene. The basin is located against the East-Vietnam Boundary Fault (EVBF) to the west and the oceanic crust to the east. Good quality seismic lines allow us to observe structures which highlight the rifting history of the South China Sea margin and the processes of crustal boudinage. A Moho rise is the prominent feature of the Central part of the basin. The mantle is shallowest in the center of the basin and at places is directly in contact with the sediments, via a large low-angle detachment fault which separates several crustal blocks. The axis of the Moho rise is roughly parallel to the South China Sea propagator direction. As a consequence, the upper and lower crusts are strongly extended by large crustal boudins. The network of normal fault is dense in the upper crust and propagates into the lower crust occasionally. However, the lower crust seems to be missing at some places. At the apex of the Moho rise, several indicators of fluids circulations have been observed, including volcanic edifices and gas escapes features. The seismic facies just above this Moho rise looks poorly stratified and might be affected by a certain degree of metamorphism. Three stages of extension are clearly identifiable, with age constrained by wells calibration of the horizons: the oldest rift sequence is identified from basement to Oligocene horizons; a second from Oligocene to Mid Miocene (15.5 Ma), and a third from Mid-Miocene to Upper Miocene (10.5 Ma). These three rifts have been formed with at least two directions of extension, a first which is North-South and a second NW - SE The well imaged 15.5 Ma horizon is tilted, as well as part of the subsequent in-filling which is fan-shaped. These are in turn sealed by the 10.5Ma unconformity. Although tectonic activity appears diachronous from north to south, we suggest that cessation of rifting and opening did not occur before 12

  14. Caribbean basin framework, 1: Introduction, Nicaraguan rise and Greater Antilles

    SciTech Connect

    Mann, P. )

    1991-03-01

    Recent progress in lithologic description and microfossil dating of onshore basins from around the Caribbean has improved constraints on the age and tectonic setting of major basin-forming periods. The author presents an integrated tectonostratigraphic summary from the northern, western, and southwestern Caribbean and use this framework to interpret seismic profiles in offshore areas lacking wells.

  15. Ice interaction with offshore structures

    SciTech Connect

    Cammaert, A.B.; Muggeridge, D.B.

    1988-01-01

    Oil platforms and other offshore structures being built in the arctic regions must be able to withstand icebergs, ice islands, and pack ice. This reference explain the effect ice has on offshore structures and demonstrates design and construction methods that allow such structures to survive in harsh, ice-ridden environments. It analyzes the characteristics of sea ice as well as dynamic ice forces on structures. Techniques for ice modeling and field testing facilitate the design and construction of sturdy, offshore constructions. Computer programs included.

  16. Offshore search continues despite disappointments

    SciTech Connect

    Cornitius, T.

    1985-05-01

    Exploration drilling activity in Australia broke records onshore in 1984, but offshore it was a different story. A total of 373 wells were drilled, onshore and offshore, with 266 labeled as wildcats and appraisals. Out of 80 wells drilled offshore last year, 43 were exploratory compared with 49 in 1983; 48 were oil wells, seven were gas, and 25 were dusters. Offshore discoveries included the Talisman 1 off the coast of Western Australia, which tested around 6000 b/d, and Challis 1 in the Timor Sea, which flowed at 5000 b/d. The failure to establish Jabiru in the Timor Sea as a major oil province like Bass Strait was a major disappointment. However, the Challis 1 was a relief since it indicated the presence of a commercial field adjacent to Jabiru.

  17. Preliminary catalog of the sedimentary basins of the United States

    USGS Publications Warehouse

    Coleman, James L., Jr.; Cahan, Steven M.

    2012-01-01

    One hundred forty-four sedimentary basins (or groups of basins) in the United States (both onshore and offshore) are identified, located, and briefly described as part of a Geographic Information System (GIS) data base in support of the Geologic Carbon Dioxide Sequestration National Assessment Project (Brennan and others, 2010). This catalog of basins is designed to provide a check list and basic geologic framework for compiling more detailed geologic and reservoir engineering data for this project and other future investigations.

  18. The Math of Khan

    ERIC Educational Resources Information Center

    Schaffhauser, Dian

    2013-01-01

    It's like a dream come true for educators: free resources available wherever a web browser can operate and with nary an iota of advertising. What's not to like? What is it about this organization, whose mission is "to provide a free, world-class education for anyone anywhere," that has provoked such vitriol? Part of it is that when its videos have…

  19. Reassessment of offshore platforms

    SciTech Connect

    Nair, V.V.D.; Kuhn, J.M. )

    1993-05-01

    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.

  20. Large internal waves in Massachusetts Bay transport sediments offshore

    USGS Publications Warehouse

    Butman, B.; Alexander, P.S.; Scotti, A.; Beardsley, R.C.; Anderson, S.P.

    2006-01-01

    A field experiment was carried out in Massachusetts Bay in August 1998 to assess the role of large-amplitude internal waves (LIWs) in resuspending bottom sediments. The field experiment consisted of a four-element moored array extending from just west of Stellwagen Bank (90-m water depth) across Stellwagen Basin (85- and 50-m water depth) to the coast (24-m water depth). The LIWs were observed in packets of 5–10 waves, had periods of 5–10 min and wavelengths of 200–400 m, and caused downward excursions of the thermocline of as much as 30 m. At the 85-m site, the current measured 1 m above bottom (mab) typically increased from near 0 to 0.2 m/s offshore in a few minutes upon arrival of the LIWs. At the 50-m site, the near-bottom offshore flow measured 6 mab increased from about 0.1 to 0.4–0.6 m/s upon arrival of the LIWs and remained offshore in the bottom layer for 1–2 h. The near-bottom currents associated with the LIWs, in concert with the tidal currents, were directed offshore and sufficient to resuspend the bottom sediments at both the 50- and 85-m sites. When LIWs are present, they may resuspend sediments for as long as 5 hours each tidal cycle as they travel westward across Stellwagen Basin. At 85-m water depth, resuspension associated with LIWs is estimated to occur for about 0.4 days each summer, about the same amount of time as caused by surface waves.

  1. Offshore Wind Energy Market Overview (Presentation)

    SciTech Connect

    Baring-Gould, I.

    2013-07-01

    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.

  2. Potential threats to offshore platforms

    SciTech Connect

    Jenkins, B.M.

    1988-01-01

    Increasingly spectacular acts of terrorism have led to growing concern that terrorists will move beyond the symbols of society and directly attack its technological and industrial vulnerabilities. Offshore platforms have been frequently mentioned among the potential targets terrorists might attack. This concern, however, has not resulted in extensive research like that devoted to possible threats to nuclear facilities, which have also been frequently mentioned as possible future targets of terrorists. For one thing, offshore drilling does not invoke the fear inherent in the word nuclear, a fear that translates directly into heavy security for the nuclear industry. Neither does the construction of offshore platforms provoke anything like the kind of protest generated by the construction of nuclear facilities.

  3. Offshore Energy Knowledge Exchange Workshop Report

    SciTech Connect

    none,

    2012-04-12

    A report detailing the presentations and topics discussed at the Offshore Energy Knowledge Exchange Workshop, an event designed to bring together offshore energy industry representatives to share information, best practices, and lessons learned.

  4. Oblique Collision of the Leeward Antilles, Offshore Venezuela: Linking Onshore and Offshore Data from BOLIVAR

    NASA Astrophysics Data System (ADS)

    Beardsley, A. G.; Avé Lallemant, H. G.; Levander, A.; Clark, S. A.

    2006-12-01

    The kinematic history of the Leeward Antilles (offshore Venezuela) can be characterized with the integration of onshore outcrop data and offshore seismic reflection data. Deformation structures and seismic interpretation show that oblique convergence and wrench tectonics have controlled the diachronous deformation identified along the Caribbean - South America plate boundary. Field studies of structural features in outcrop indicate one generation of ductile deformation (D1) structures and three generations of brittle deformation (F1 - F3) structures. The earliest deformation (D1/F1) began ~ 110 Ma with oblique convergence between the Caribbean plate and South American plate. The second generation of deformation (F2) structures initiated in the Eocene with the extensive development of strike-slip fault systems along the diffuse plate boundary and the onset of wrench tectonics within a large-scale releasing bend. The most recent deformation (F3) has been observed in the west since the Miocene where continued dextral strike-slip motion has led to the development of a major restraining bend between the Caribbean plate transform fault and the Oca - San Sebastian - El Pilar fault system. Deformation since the late Cretaceous has been accompanied by a total of 135° clockwise rotation. Interpretation of 2D marine reflection data indicates similar onshore and offshore deformation trends. Seismic lines that approximately parallel the coastline (NW-SE striking) show syndepositional normal faulting during F1/F2 and thrust faulting associated with F3. On seismic lines striking NNE-SSW, we interpret inversion of F2 normal faults with recent F3 deformation. We also observe both normal and thrust faults related to F3. The thick sequence of recent basin sedimentation (Miocene - Recent), interpreted from the seismic data, supports the ongoing uplift and erosion of the islands; as suggested by fluid inclusion analysis. Overall, there appears to be a strong correlation between

  5. Climate and offshore energy resources

    NASA Astrophysics Data System (ADS)

    Twitchell, P. F.

    1980-12-01

    A conference discussed the relationship of climate to the world's offshore energy resources. The conference focused upon such areas as the impact of oil resources upon the economies of developed and developing countries, the importance of providing climatic data in sufficient time to meet users' needs, and the hazards and financial burdens associated with the development of offshore oil reserves. One of the important achievements of the confidence was the establishment of better communications between the users of environmental data and those charged with producing predictions.

  6. China, JNOC start exploration in Tarim basin

    SciTech Connect

    Not Available

    1992-06-15

    This paper reports that a joint venture of China National Oil and Natural Gas Corp and Japan National Oil Corp (JNOC) has begun exploration in Northwest China's remote Tarim basin in Xinjiang Uygur Autonomous Region. That marks the first time China has allowed a foreign oil company to participate in exploration of the highly prospective basin. China pins much of its hope for the future on the Tarim basin as production declines from its older, mainstay fields in the east and offshore results have proved largely disappointing. The Chinese-Japanese combine began operations in the southwest part of the 560,000 sq km basin. The 200 member exploration team plans to complete a seismic survey covering 3,500 line km in the Kashi and Yecheng areas during the next 4 1/2 years. The survey follows a feasibility study that began last October covering 30,000 sq km in the basin.

  7. Eighteenth annual offshore technology conference. Volume 1

    SciTech Connect

    Not Available

    1986-01-01

    These sixty papers were given at a conference on offshore technology. Topics covered include friction effects of driving piles into sea beds of various compositions, wave forces on offshore platforms, stability, materials testing of various components such as plates, legs, wellheads, pipe joints, and protection of offshore platforms against ice and collision with icebergs.

  8. Peru onshore-deepwater basins should have large potential

    SciTech Connect

    Zuniga-Rivero, F.; Keeling, J.A.; Hay-Roe, H.

    1998-10-19

    Perupetro`s recent announcement that 13 offshore exploration blocks of nearly 1 million acres each will be offered for bids in the fourth quarter of 1998 has reawakened interest in this extensive, largely unexplored area. The new government policy, combined with the results of modern, deep-probing seismic surveys, has already led to a stepped-up search for oil and gas that will probably escalate. Most of Peru`s ten coastal basins are entirely offshore, but at both ends of the 1,500-mile coastline the sedimentary basins stretch from onshore across the continental shelf and down the continental slope. Two of these basin areas, both in the north, have commercial production. The third, straddling the country`s southern border, has never been drilled either on land or offshore. The Peruvian sectors of these three basins total roughly 50,000 sq miles in area, 75% offshore. All have major oil and gas potential. They are described individually in this article, an update in the ongoing studies last reported at the 1998 Offshore Technology Conference and in the first article of this series.

  9. Foundations for offshore wind turbines.

    PubMed

    Byrne, B W; Houlsby, G T

    2003-12-15

    An important engineering challenge of today, and a vital one for the future, is to develop and harvest alternative sources of energy. This is a firm priority in the UK, with the government setting a target of 10% of electricity from renewable sources by 2010. A component central to this commitment will be to harvest electrical power from the vast energy reserves offshore, through wind turbines or current or wave power generators. The most mature of these technologies is that of wind, as much technology transfer can be gained from onshore experience. Onshore wind farms, although supplying 'green energy', tend to provoke some objections on aesthetic grounds. These objections can be countered by locating the turbines offshore, where it will also be possible to install larger capacity turbines, thus maximizing the potential of each wind farm location. This paper explores some civil-engineering problems encountered for offshore wind turbines. A critical component is the connection of the structure to the ground, and in particular how the load applied to the structure is transferred safely to the surrounding soil. We review previous work on the design of offshore foundations, and then present some simple design calculations for sizing foundations and structures appropriate to the wind-turbine problem. We examine the deficiencies in the current design approaches, and the research currently under way to overcome these deficiencies. Designs must be improved so that these alternative energy sources can compete economically with traditional energy suppliers. PMID:14667305

  10. National Offshore Wind Energy Grid Interconnection Study

    SciTech Connect

    Daniel, John P.; Liu, Shu; Ibanez, Eduardo; Pennock, Ken; Reed, Greg; Hanes, Spencer

    2014-07-30

    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.

  11. Circum-Arctic lithospheric transects from onshore to offshore

    NASA Astrophysics Data System (ADS)

    Pease, V.; Coakley, B.; Faleide, J. I.; Jokat, W.; Miller, E. L.; Stephenson, R.; Meisling, K. E.

    2015-12-01

    Understanding the evolution of the lithosphere over time involves the integration and interpretation of geological and geophysical data, combined with good knowledge of the physical processes at work in the lithosphere giving rise to past and present structures. Tectonic activity related to the rifting process created the present-day structure of today's Arctic basins and bathymetric highs, and in the process modified older structures and architecture of the crust and lithosphere. The correlation of circum-Arctic terranes and orogens help to not only reconstruct paleogeography but to also define the role and determine the nature of the lithospheric processes that were active in the complex tectonic evolution of the Arctic. CALE (Circum Arctic Lithosphere Evolution), an international and multidisciplinary effort involving c. 35 geologists and geophysicists from ten different countries working to link the onshore and offshore regions across the circum-Arctic region, is a scientific network in it's last year of a 5-year program. Sedimentary cover and crust to mantle cross-sections from onshore to offshore have been created integrating the latest scientific knowledge and data sets available for the Arctic. The project's principal Arctic transects include: Ellesmere-Canada Basin, Pacific Ocean-Lomonosov Ridge through the Bering Strait, across the Laptev Sea rift to the DeLong Islands, Barents and Kara regions across Timan-Pechora and Taimyr. These sections, the culmination of the CALE project, and their principle findings will be presented for the first time with discussion of outstanding issues yet to be resolved.

  12. Promise seen in Petrel sub-basin off northwestern Australia

    SciTech Connect

    Maung, T.U.; Passmore, V. )

    1995-01-30

    The Australian government during the past 11 years has been regularly releasing vacant areas on the Australian continental shelf for exploration. Although Australia's offshore basins cover an area of 12 million sq km, only about 1,100 exploration and development wells have been drilled, and most of the basins are underexplored by world standards. One of these areas is the Petrel sub-basin of the Bonaparte basin in water shallower than 100 m off Northwest Australia. The government recently released six areas in the southern offshore Petrel subbasin for petroleum exploration. The results of a study by the Petroleum Resources Branch of the bureau of Resource Sciences have been synthesized into a Petrel Sub-basin Bulletin, some selections of which are discussed in this article. Although there are over 44,000 km of seismic data recorded in the sub-basin, the quality of pre-1979 data is very poor to poor, and only 15,800 km of data recorded between 1980--94 (including 1,000 km of 3D seismic data over the Barnett structure) are of fair to good quality. The paper describes the regional geology, reservoir and seals, source rocks, and types of geologic traps. The study identified over 30 structures and leads in the offshore southern Petrel sub-basin. Significant opportunities exist for delineation and definition of drillable prospects in this promising Australian petroleum province.

  13. Quantifying the Hurricane Risk to Offshore Wind Power (Invited)

    NASA Astrophysics Data System (ADS)

    Apt, J.; Rose, S.; Jaramillo, P.; Small, M.

    2013-12-01

    The U.S. Department of Energy has estimated that over 50 GW of offshore wind power will be required for the United States to generate 20% of its electricity from wind. Developers are actively planning offshore wind farms along the U.S. Atlantic and Gulf coasts and several leases have been signed for offshore sites. These planned projects are in areas that are sometimes struck by hurricanes. Whether that risk will grow as a result of climate change is uncertain. Recent years have seen an increase in hurricane activity in the Atlantic basin (1) and, all else being equal, warmer sea surface temperatures can be expected to lead to increased storm intensity. We have developed a method to estimate the catastrophe risk to offshore wind power using simulated hurricanes (2). In Texas, the most vulnerable region we studied, 10% of offshore wind power could be offline simultaneously due to hurricane damage with a 100-year return period and 6% could be destroyed in any 10-year period. Much of the hurricane risk to offshore wind turbines can be mitigated by designing turbines for higher maximum wind speeds, ensuring that turbine nacelles can turn quickly to track the wind direction even when grid power is lost, and building in areas with lower risk. 1. Iris Grossmann and M. Granger Morgan, "Tropical Cyclones, Climate Change, and Scientific Uncertainty: What do we know, what does it mean, and what should be done?," Climatic Change, 108, pp 543-579, 2011. 2. Carnegie Mellon Electricity Industry Center Working Paper CEIC-13-07, http://wpweb2.tepper.cmu.edu/electricity/papers/ceic-13-07.asp This work was supported in part by the EPA STAR fellowship program, a grant from the Alfred P. Sloan Foundation and EPRI to the Carnegie Mellon Electricity Industry Center, and by the Doris Duke Charitable Foundation, the R.K. Mellon Foundation and the Heinz Endowments for support of the RenewElec program at Carnegie Mellon University. This research was also supported in part by the Climate and

  14. Stratigraphic and sedimentological observations from seismic data across the Chicxulub impact basin

    NASA Astrophysics Data System (ADS)

    Bell, C.; Morgan, J. V.; Hampson, G. J.; Trudgill, B.

    2004-07-01

    Seismic data across the offshore half of the Chicxulub impact crater reveal a 145 km diameter post-impact basin to be a thickening of Tertiary sediment, which thickens by ~0.7 sec from the basin margin to the basin center. The basin existed long after the impact and was gradually infilled to its current flat surface. A suite of seismic horizons within the impact basin have been picked on four reflection lines across the crater. They reveal that the western and northwestern parts of the impact basin were filled first. Subsequently, there was a dramatic change in the depositional environment, indicated by an unconformable surface that can be mapped across the entire basin. A prograding shelf sequence downlaps onto this unconformity in the eastern basin. The seismic stratigraphic relationships suggest a marine regression, with sedimentation becoming gradually more passive as sediments fill the eastern part of the impact basin. The central and northeastern parts of the basin are filled last. The onshore hole Yaxcopoil-1 (Yax-1), which was drilled on the flanks of the southern basin, has been projected onto the offshore seismic data to the west of the crater center. Using dates obtained from this onshore well and regional data, approximate ages have been placed on the most significant horizons in the offshore seismic data. Our preliminary interpretation is that the western and northwestern basins were almost entirely filled by 40 Ma and that the marine regression observed in the eastern basin is early Miocene in age. Offshore seismic stratigraphic analyses and onshore data within Yax-1 suggest that the early Paleocene is highly attenuated across the impact basin. The Mesozoic section appears to be ~1 km thicker offshore than onshore. We calculate that, given this offshore thickening, the volume of Mesozoic rocks that have been excavated, melted, or vaporized during impact is around 15% larger than expected from calculations that assume the offshore thickness is equal to

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

    SciTech Connect

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

    2012-11-01

    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.

  16. Hydrocarbon prospects of southern Indus basin, Pakistan

    SciTech Connect

    Quadri, V.U.N.; Shuaib, S.M.

    1986-06-01

    The Southern Indus basin extends approximately between lat. 23/sup 0/ and 28/sup 0/31'N, and from long. 66/sup 0/E to the eastern boundary of Pakistan. Of the 55 exploratory wells drilled (1955-1984), 27 were based on results of multifold seismic surveys. Five commercial oil discoveries and one gas discovery in Cretaceous sands, three gas discoveries in Paleocene limestone or sandstone, and one gas-condensate discovery from lower Eocene limestone prove that hydrocarbons are present. The main hydrocarbon fairways are Mesozoic tilted fault blocks. Tertiary reefal banks, and drape and compressional anticlines. Older reservoirs are accessible toward the east and northeast, and younger mature source rocks are to the west, including offshore, of the Badin block oil field area. The Indus offshore basin reflects sedimentation associated with Mesozoic rifting of the Pakistan-Indian margin, superimposed by a terrigenous clastic depositional system comprised of deltas, shelves, and deep-sea fans of the Indus River.

  17. At the tip of a propagating rift - The offshore East African Rift

    NASA Astrophysics Data System (ADS)

    Franke, Dieter; Jokat, Wilfried; Ladage, Stefan; Stollhofen, Harald; Klimke, Jennifer; Lutz, Ruediger; Mahanjane, Stefane; Ehrhardt, Axel; Schreckenberger, Bernd

    2016-04-01

    Numerous studies have addressed various aspects of the East African Rift system (EARS) but surprisingly few the offshore continuation of the south-eastern branch of the rift into the Mozambique Channel. Here, we present new evidence for neotectonic deformation derived from modern seismic reflection data and supported by additional geophysical data. The Kerimbas Graben offshore northern Mozambique is the most prominent manifestation of sub-recent extensional deformation. The seismic reflection data reveals that recent normal faulting often utilizes preexisting, deeply buried half-graben structures which likely are related to the formation of the Somali Basin. The ~30 km wide and ~150 km long symmetric graben is in a stage where the linkage of scattered normal faults already did happen, resulting in increased displacement and accommodation of most of the extension across the basin. However, deep earthquakes below the rift indicate a strong and still preserved lithospheric mantle. Extension is becoming diffuse where an onshore suture, subdividing the northern from the southern metamorphic basement onshore Mozambique, is closest to the offshore rift. It appears likely that this suture is the origin for the variation in rifting style, indicating that mantle fabric resulting from a Cambrian collision has been preserved as mechanical anisotropy of the lithospheric mantle. Further south the rift focuses in an about 30 km wide half-graben. An important finding is that the entire offshore branch of the EARS lacks significant volcanism. Along the offshore EARS there are only negligible indications for recent volcanism in the reflection seismic data such as sills and dikes. Apparently the "Comoros mantle plume" (French and Romanowicz, 2015) has a very minor influence on the progressive extensional deformation along the northern Mozambique continental margin, leading eventually to breakup sometimes in the future. Combining structural with earthquake data reveals that the magma

  18. Chicxulub impact basin: Gravity characteristics and implications for basin morphology and deep structure

    NASA Technical Reports Server (NTRS)

    Sharpton, Virgil L.; Burke, Kevin; Hall, Stuart A.; Lee, Scott; Marin, Luis E.; Suarez, Gerardo; Quezada-Muneton, Juan Manuel; Urrutia-Fucugauchi, Jaime

    1993-01-01

    The K-T-aged Chicxulub Impact Structure is buried beneath the Tertiary carbonate rocks of the Northern Yucatan Platform. Consequently its morphology and structure are poorly understood. Reprocessed Bouguer (onshore) and Free Air (offshore) gravity data over Northern Yucatan reveal that Chicxulub may be a 200-km-diameter multi-ring impact basin with at least three concentric basin rings. The positions of these rings follow the square root of 2 spacing rule derived empirically from analysis of multi-ring basins on other planets indicating that these rings probably correspond to now-buried topographic basin rings. A forward model of the gravity data along a radial transect from the southwest margin of the structure indicates that the Chicxulub gravity signature is compatible with this interpretation. We estimate the basin rim diameter to be 204 +/- 16 km and the central peak ring diameter (D) is 104 +/- 6 km.

  19. Fatigue handbook: Offshore steel structures

    SciTech Connect

    Almarnaess, A.

    1985-01-01

    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.

  20. Offshore sand and gravel mining

    SciTech Connect

    Pandan, J.W.

    1983-05-01

    This paper reviews the status of mining offshore for sand and gravel on a world-wide basis. It discusses the technology for exploration and evaluation of sea floor mineral targets, as well as mining, transportation, and processing. Large operations in Japan and Europe are described, based upon personal observations of the author. The U.S. situation is outlined and opinions offered as to the outlook for the future.

  1. Pipelaying in artic offshore waters

    SciTech Connect

    Langner, C. G.

    1985-11-19

    The present invention provides a method and apparatus for constructing pipelines in Arctic offshore waters by a directional drilling technique, thereby minimizing exposure to ice gouging and eliminating the hazards associated with unstable permafrost. A special drilling-pipe-line construction vessel is also provided which has a conical shape with reinforced outer walls to resist ice forces, which vessel includes means to install deep underground pipeline segments and means to connect and protect the pipe ends.

  2. Two offshore Australian crudes assayed

    SciTech Connect

    Rhodes, A.K.

    1994-05-09

    Two light, sweet crudes from offshore Australia have been assayed. Gippsland crude, also called Bass Strait, is produced off the coast of Victoria, in southeastern Australia. The 47 API, 0.09% sulfur crude was analyzed in mid-1993. Skua, a 42 API, 0.06 wt % sulfur crude, is produced in the Timor Sea. Data are given on the whole crude and fractions for both deposits. Both chemical and physical properties are listed.

  3. Offshore oil: Correctness of perspective

    SciTech Connect

    Burns, R.F.

    1993-05-01

    Except for the Gulf of Mexico, the offshore oil industry has been virtually banned from the US Exclusive Economic Zone for ten years. The oil potential in Alaska's Arctic National Wildlife Refuge (ANWR) is also off limits. The Gulf of Mexico is the only place with prospects for future success and a number of companies both large and small are determined to move forward. The depressed price of oil does not encourage development but recently gas prices in the US have increased, making offshore gas development more feasible. Perhaps most significant is development and application of new technology and more intense management to make sure it works. The offshore oil companies and support industries have made significant technological advances, expending over and above the dollars paid in taxes, lease fees, and royalties. The ocean industries harbor a great reservoir of high technology knowledge. They have demonstrated the ability to successfully meet a vast array of challenges in exploring for, drilling, and producing oil and gas in extreme conditions. These facts beg the question as to the rational basis of each and every regulation and the ban on drilling.

  4. Structural development of the western Makran Accretionary Complex, Offshore Iran

    NASA Astrophysics Data System (ADS)

    Burberry, C. M.; Jackson, C. A.

    2013-12-01

    The Makran Accretionary Complex (MAC), which straddles the southern offshore regions of Iran and Pakistan, is a fold-thrust system bound by the Murray Ridge and Ornach Nal Fault to the east, and the Minab Fault System (MFS) to the west. It is c. 1000 km wide and the frontal c. 125 km of the system is submerged beneath the Gulf of Oman. Relatively little is known about this system, despite the fact that constitutes a large portion of the Central Tethyan Orogen and is one of the largest accretionary complexes in the world. We use offshore 2D seismic reflection data to investigate the structural style and evolution of the Iranian segment of the MAC. The MAC is divided into two morphologically distinct domains: (i) a northern domain (Domain 1), which is located landward of a prominant break-in-slope on the seabed and is characterised by a series of normal fault-bound sub-basins that are approximately 50 km wide, and which contain numerous, unconformity-bound seismic units; and (ii) a southern domain (Domain 2), which is located basinward of the prominent seabed slope break, and is characterised by alternating ridges and troughs. Seismic data indicate that these structures are laterally continuous (over 100 km long) north-dipping thrust faults, which are overlain by south-verging, non-cylindrical, fault-propagation folds. Towards the western end of the study area, immediately offshore of the prominent onshore trace of the MFS, there is no single structure that can be reliably interpreted as the offshore extension of the MFS. Instead, a series of oblique-slip faults with thrust and strike-slip components are identified, spanning a zone that is c. 40 km wide. In the north and close to the coastline, the faults are dominantly strike-slip, whereas further south, closer to the deformation front, the thrust-sense component is more important. Irrespective of their slip sense, faults in this zone have a similar N-S strike to the onshore trace of the MFS. In addition, the basin

  5. Post-breakup Basin Evolution along the South-Atlantic Margins

    NASA Astrophysics Data System (ADS)

    Strozyk, Frank; Back, Stefan; Kukla, Peter

    2014-05-01

    The post-breakup tectono-stratigraphic evolution of large offshore basins along the South American and African continental margins record strongly varying post-rift sedimentary successions. The northernmost segment of the South Atlantic rift and salt basins is characterized by a pronounced asymmetry, with the Brazilian margin comprising narrower and deeper rift basins with less salt in comparison to the Congo-Gabon conjugate margin. Another important observation is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. A regional comparison based on tectonic-stratigraphic analysis of selected seismic transects between the large basins offshore southern Brazil (Espirito Santo Basin, Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Lower Congo Basin, Kwanza Basin, Namibe Basin, Walvis Basin) provides a comprehensive basin-to-basin documentation of the key geological parameters controlling ocean and continental margin development. This comparison includes the margin configuration, subsidence development through time, sediment influx and storage patterns, type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems) and finally major tectonic and magmatic events. Data from the salt basins indicate that salt-related tectonic deformation is amongst the prime controls for the non-uniform post-rift margin development. The diversity in the stratigraphic architecture of the conjugate margins offshore southern Brazil, Namibia and Angola reflects variations in the interplay of a number of controlling factors, of which the most important are (a) the structural configuration of each margin segment at the time of break-up, (b) the post break-up subsidence history of the respective margin segment

  6. Offshore Socotra, Republic of Yemen: Potential for a new hydrocarbon province?

    SciTech Connect

    Richardson, S.M.; Bott, W.F.; Birse, T.C.R.

    1995-08-01

    A new plate reconstruction has enabled the Island of Socotra, currently located in the Gulf of Aden adjacent to the Somalian coast, to be confidently restored to its original spatial position, adjacent to the southern Omani coastline. New studies integrated with these plate reconstructions, have confirmed the presence of an untested Mesozoic graben, which trends across the Socotra platform. Fieldwork carried out in the region now enables a SE extension of the prolific Lower Cretaceous Qishn `play` (delinated in the Masilah Basin, onshore Yemen) to be postulated offshore into the Gulf of Aden. Following the award of offshore acreage adjacent to the Island of Socotra, exploration studies have confirmed the presence of the Qishn `play` both on the Island of Socotra, and offshore in the one available basin-margin control well. This work has also identified two additional plays: the Shuabia-equivalent carbonates, which are prolific producing reservoirs in central Oman; and the Permo-Triassic clastics, which may provide a new reservoir target for the region. Fieldwork has also identified Jurassic siliclastics outcropping on the Island, which may provide further reservoir potential. Ongoing multidisciplinary studies, integrating the results of a detailed geophysical interpretation with high resolution structural-stratigraphic studies, have confirmed the presence of large structures within an undrilled Mesozoic rift-basin, which will be tested during 1995.

  7. Sequence stratigraphic framework of Neogene strata in offshore Nigeria

    SciTech Connect

    Pacht, J.A.; Bowen, B.E.; Hall, D.J.

    1996-08-01

    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.

  8. Potential on-shore and off-shore reservoirs for CO2 sequestration in Central Atlantic magmatic province basalts

    PubMed Central

    Goldberg, David S.; Kent, Dennis V.; Olsen, Paul E.

    2010-01-01

    Identifying locations for secure sequestration of CO2 in geological formations is one of our most pressing global scientific problems. Injection into basalt formations provides unique and significant advantages over other potential geological storage options, including large potential storage volumes and permanent fixation of carbon by mineralization. The Central Atlantic Magmatic Province basalt flows along the eastern seaboard of the United States may provide large and secure storage reservoirs both onshore and offshore. Sites in the South Georgia basin, the New York Bight basin, and the Sandy Hook basin offer promising basalt-hosted reservoirs with considerable potential for CO2 sequestration due to their proximity to major metropolitan centers, and thus to large industrial sources for CO2. Onshore sites are suggested for cost-effective characterization studies of these reservoirs, although offshore sites may offer larger potential capacity and additional long-term advantages for safe and secure CO2 sequestration. PMID:20080705

  9. Wave slamming on offshore structures

    NASA Astrophysics Data System (ADS)

    Miller, B. L.

    1980-03-01

    Experimental and theoretical work on the slamming of circular cylinders is surveyed. Data are included from controlled drop tests. The influence of inclined impact and beam dynamics on the resulting stresses is calculated for a wide range of wave conditions. The statistical distributions of the estimated stresses are analyzed to provide data for the calculation of slamming loads on fixed offshore structures using simple formulas in which the slamming coefficients incorporate both the member dynamics and the sea wave statistics. Slamming coefficients and associated stress calculation methods are presented for extreme values and fatigue damage. These may also be used for slamming during jacket launching. A film of wave slam was also produced.

  10. Offshore drilling and production structure

    SciTech Connect

    Crockett, R.K.; Palmer, H.E.; Stenning, D.G.

    1982-02-09

    The invention relates to an off-shore marine structure that provides an elevated support for a drilling and/or production platform. A structure comprised of three interlocking components is provided, the first component being a large foundation base installed on the sea bed; the second being a conical shaped support component which is engagable with the foundation base and which, releasably carries the third platform supporting component. In the preferred form, the platform supporting component comprises a centrally-disposed vertical column, means being provided to facilitate engagement of the column with the platform and the second component and to subsequently elevate the platform to an operating height above sea level.

  11. Growth and yield of rice as affected by transplanting dates and seedlings per hill under high temperature of Dera Ismail Khan, Pakistan

    PubMed Central

    Baloch, Mohammad Safdar; Awan, Inayat Ullah; Hassan, Gul

    2006-01-01

    Studies were initiated for two consecutive years to find out the effect of time of transplanting and seedlings hill−1 on the productivity of rice in Dera Ismail Khan district of North West Frontier Province (NWFP), Pakistan. The experiment was laid out in a randomized complete block design with split plot arrangements. Main plots consisted of four transplanting dates viz. 20th and 27th of June and 4th and 11th of July while sub-plots contained 1, 2, 3 or 4 seedlings hill−1. Among transplanting dates, June 20th planted crop gave highest paddy yield and net return with 1 seedling hill−1. It explains that the use of more seedlings hill−1 not only adds to cost but is also a mere wastage of natural resources. Based on research findings, we conclude that the use of 1 seedling hill−1 is most appropriate for timely sowing otherwise 4 seedlings hill−1 should be used to compensate for the yield gap in late transplanted rice. PMID:16773732

  12. 31 CFR 547.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 547.406 Section 547.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... REGULATIONS Interpretations § 547.406 Offshore transactions. The prohibitions in § 547.201 on transactions...

  13. 31 CFR 542.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 542.406 Section 542.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... § 542.406 Offshore transactions. The prohibitions in § 542.201 on transactions involving...

  14. 31 CFR 588.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 588.406 Section 588.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Interpretations § 588.406 Offshore transactions. The prohibitions in § 588.201 on transactions involving...

  15. 31 CFR 598.407 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 598.407 Section 598.407 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Interpretations § 598.407 Offshore transactions. The prohibitions contained in § 598.203 apply to transactions...

  16. 31 CFR 543.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 543.406 Section 543.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... Interpretations § 543.406 Offshore transactions. The prohibitions in § 543.201 on transactions or...

  17. 31 CFR 546.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 546.406 Section 546.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE... § 546.406 Offshore transactions. The prohibitions in § 546.201 on transactions or dealings...

  18. U.S. Offshore Wind Port Readiness

    SciTech Connect

    C. Elkinton, A. Blatiak, H. Ameen

    2013-10-13

    This study will aid decision-makers in making informed decisions regarding the choice of ports for specific offshore projects, and the types of investments that would be required to make individual port facilities suitable to serve offshore wind manufacturing, installation and/or operations.

  19. Domestic Options to Offshore Oil and Gas.

    ERIC Educational Resources Information Center

    Kash, Don E.

    1983-01-01

    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.…

  20. Application of low density foam pigs offshore Brazil

    SciTech Connect

    Lima, P.C.R.; Alves, S.J.

    1995-12-31

    In complex offshore installations, such as in the Campos Basin, it is relatively common to encounter pipeline systems where conventional pigs can not be run due to several factors. Changing pipe diameters, and presence of wet X-mas trees and manifolds are the most troublesome ones. In this work a new successful concept of using low cost and low density foam pigs for both liquid removal in wet-gas pipelines, and paraffin removal in oil and multiphase flow pipelines, is presented. Experimental work conducted in a 4 in laboratory facility, including a small scale glass manifold and a 6 in steel manifold, proved these pigs to be very effective. The performance of almost all kind of flexible polyurethane foams manufactured in Brazil is evaluated. Three field tests are also reported. The first low density foam pig operation was performed on a 127 mile long, 16 in diameter wet-gas offshore pipeline where the foam pig showed even higher liquid removal efficiency than the conventional inflatable spheres. The second operation was performed on a 6 mile long, 12 in diameter multiphase production offshore pipeline, which has never been pigged during its 9 year operation, and resulted in the removal of approximately 200 tons of paraffin. Finally, the third successful case is the cleaning of a 2 mile long flexible flow line of a subsea completed satellite well, in which the foam pigs were sent through a 2.5 in gas lift line, through a wet x-mas tree, not designed to be pigged, and then back through the 4 in production flow line. In spite of the fact that this paper is focusing on condensate and paraffin removal in pipeline, the basic principles can be applied to several kinds of operations: general pipeline cleaning; products separation in pipeline; corrosion evaluation; chemical product application.

  1. Chronostratigraphy of Plio-Pleistocene sequences, offshore Louisiana

    SciTech Connect

    Scott, R.W. )

    1991-03-01

    Plio-Pleistocene cool stages correlate with sequence boundaries in the Gulf of Mexico, offshore Louisiana. The cool/warm stages are defined by planktonic foram assemblages in the Vema 16-205 core in the eastern tropical Atlantic. The mean duration of each climatic stage was 230,000 years. These climatic stages were incorporated into a composite standard section with oxygen isotope events, planktonic foraminiferal and nannofossil datums, and magnetostratigraphic events from oceanic core holes: DSDP 502 in the Columbia basin, Caribbean; DSDP 552 on the Rockall Plateau, northeast Atlantic; DSDP 572C in the equatorial Pacific; Vema 28 core 219 on the Solomon Rise, west Pacific; and the Eureka 57 core 135 in DeSoto Canyon, offshore Florida. The oxygen isotope events and the paleontologic datums were identified in two exploration wells in the Green Canyon block, offshore Louisiana, and correlated with seismic sequence boundaries. Iterative graphic correlation with the composite standard refines the positions of the tops of the isotope events where data noise makes the pick equivocal providing a precise, high-resolution correlation tool. Each oxygen isotope event represents approximately 31,000 years. The sequences in the Green Canyon area are from 300 m to 800 m thick, and were deposited at rates from 800 to 1500 cm/ka. The duration of the hiatuses at the sequence boundaries range from 27,000 to 200,000 years. These seismic/depositional sequences were deposited during the alter parts of the cool stage and the warm climates, which indicate rising sea level to highstand. The ages of the sequence boundaries are approximately 500,000 years, 900,000 years, 1.5 Ma, 2.0 Ma, 2.7 Ma, 3.0 Ma, and 3.75 Ma.

  2. Viet Nam steps up offshore E and D push

    SciTech Connect

    Not Available

    1992-06-22

    This paper reports on Viet Nam's offshore exploration and development. Hanoi tentatively awarded three of five remaining blocks of prime offshore South China Sea acreage to companies from Europe and the Far East, with a fourth such award reported imminent. And state owned Petrovietnam signed a production sharing contract (PSC) covering acreage in the same area to a combine of British Petroleum Co. plc and Norway's Den norske stats oljeselskap AS. Retention of one block in the area covered by Viet Nam's second bidding round fueled speculation Hanoi is holding it in reserve for U.S. companies to enter bidding, pending easing of U.S. trade sanctions against Viet Nam, Agence France France (AFP) reported. Second round blocks have been carved from a concession held by Vietsovpetro, a joint venture of Petrovietnam and the former Soviet Union. All are in the southern Con Sun basin of the South China Sea off the port of Vung Tao and on trend with Viet Nam's only producing oil fields.

  3. Electrokinetic improvement of offshore foundations

    NASA Astrophysics Data System (ADS)

    Micic, Silvana

    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

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

    SciTech Connect

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

    2014-07-01

    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.

  5. Simulation modeling of stratigraphic sequences along the Louisiana offshore

    SciTech Connect

    Kendall, C.G.S.C. ); Lowrie, A.

    1990-09-01

    Sequence stratigraphic analysis of a representative (schematic) dip seismic section along the Louisiana offshore reveals 4th order (Milankovitch) sea-level cycles within 3rd order sequences. This representative line is characteristic of a dip section along the western area where progradation has exceeded subsidence by multifold since the upper Miocene, the last 6.7 m.y., and by twofold through the rest of the Miocene, back to at least 22 m.y. ago. Lowstands cause the outer shelf to act as a sediment bypass zone with shelf deposition during highstands. Salt-sediment interaction is isostatic, the adjustments occurring principally during lowstands. This interpreted stratigraphy has been simulated on an interactive computer program (SEDPAK) developed at the University of South Carolina. SEDPAK erects models of sedimentary geometries by filling in a two-dimensional basin from both sides with a combination of clastic sediment and/or in situ and transported carbonate sediments. Data inputs include the initial basin configuration, local tectonic behavior, sea-level curves, and the amount and source direction of clastic sediment as a function of water depth. The modeled geometries of clastic sediments evolve through time and respond to depositional processes that include tectonic movement, eustasy, sedimentation, sediment compaction, and isostatic response, sedimentary bypass, erosion, and deposition in various physiographic settings such as coastal plains, continental shelf, basin slope, and basin floor. The computer simulation allows for a quantification of the various processes noted and described in the interpretation. Sedimentation rates, isostatic adjustment, and tectonic movement are given in cm/year. Simulation modeling of sequence stratigraphy is seen as a next logical step in the quest for detailed and quantified interpretations.

  6. Offshore Wind Energy Systems Engineering Curriculum Development

    SciTech Connect

    McGowan, Jon G.; Manwell, James F.; Lackner, Matthew A.

    2012-12-31

    Utility-scale electricity produced from offshore wind farms has the potential to contribute significantly to the energy production of the United States. In order for the U.S. to rapidly develop these abundant resources, knowledgeable scientists and engineers with sound understanding of offshore wind energy systems are critical. This report summarizes the development of an upper-level engineering course in "Offshore Wind Energy Systems Engineering." This course is designed to provide students with a comprehensive knowledge of both the technical challenges of offshore wind energy and the practical regulatory, permitting, and planning aspects of developing offshore wind farms in the U.S. This course was offered on a pilot basis in 2011 at the University of Massachusetts and the National Renewable Energy Laboratory (NREL), TU Delft, and GL Garrad Hassan have reviewed its content. As summarized in this report, the course consists of 17 separate topic areas emphasizing appropriate engineering fundamentals as well as development, planning, and regulatory issues. In addition to the course summary, the report gives the details of a public Internet site where references and related course material can be obtained. This course will fill a pressing need for the education and training of the U.S. workforce in this critically important area. Fundamentally, this course will be unique due to two attributes: an emphasis on the engineering and technical aspects of offshore wind energy systems, and a focus on offshore wind energy issues specific to the United States.

  7. Independent focuses Philippines exploration on Visayan basin

    SciTech Connect

    Rillera, F.G.

    1995-08-21

    Cophil Exploration Corp., a Filipino public company, spearheaded 1995 Philippine oil and gas exploration activity with the start of its gas delineation drilling operations in Libertad, northern Cebu. Cophil and its Australian partners, Coplex Resources NL and PacRim Energy NL, have set out to complete a seven well onshore drilling program within this block this year. The companies are testing two modest shallow gas plays, Libertad and Dalingding, and a small oil play, Maya, all in northern Cebu about 500 km southeast of Manila. Following a short discussion on the geology and exploration history of the Visayan basin, this article briefly summarizes Cophil`s ongoing Cebu onshore drilling program. Afterwards, discussion focuses on identified exploration opportunities in the basin`s offshore sector.

  8. Coupled onshore erosion and offshore sediment loading as causes of lower crust flow on the margins of South China Sea

    NASA Astrophysics Data System (ADS)

    Clift, Peter D.

    2015-12-01

    Hot, thick continental crust is susceptible to ductile flow within the middle and lower crust where quartz controls mechanical behavior. Reconstruction of subsidence in several sedimentary basins around the South China Sea, most notably the Baiyun Sag, suggests that accelerated phases of basement subsidence are associated with phases of fast erosion onshore and deposition of thick sediments offshore. Working together these two processes induce pressure gradients that drive flow of the ductile crust from offshore towards the continental interior after the end of active extension, partly reversing the flow that occurs during continental breakup. This has the effect of thinning the continental crust under super-deep basins along these continental margins after active extension has finished. This is a newly recognized form of climate-tectonic coupling, similar to that recognized in orogenic belts, especially the Himalaya. Climatically modulated surface processes, especially involving the monsoon in Southeast Asia, affects the crustal structure offshore passive margins, resulting in these "load-flow basins". This further suggests that reorganization of continental drainage systems may also have a role in governing margin structure. If some crustal thinning occurs after the end of active extension this has implications for the thermal history of hydrocarbon-bearing basins throughout the area where application of classical models results in over predictions of heatflow based on observed accommodation space.

  9. Image processing in offshore engineering

    SciTech Connect

    Rodriguez, M.V.R.; A. Oliveira, M. de; Almeida, M.E.T. de; Lorenzoni, C.; Ferrante, A.J.

    1995-12-31

    The technological progress which has taken place during the last decade introduced a totally new outlook regarding the professional computational environment in general, and regarding the engineering profession in particular. During many years engineering computing was performed based on large computer centers, getting bigger and bigger all the time, going from mainframes to super computers, essentially producing numerical results on paper media. Lately, however, it has been realized that a much more productive computational environment can be implemented using an open architecture of client/server type, based on smaller lower cost equipment including workstations and PC`s, and considering engineering information in a broader sense. This papers reports briefly the experience of the Production Department of Petrobras in transforming its centralized, mainframe based, computational environment into a open distributed client/server computational environment, focusing on the problem of handling technical graphics information regarding its more than 70 fixed offshore platforms.

  10. 46 CFR 90.10-40 - Offshore supply vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Offshore supply vessels. 90.10-40 Section 90.10-40... PROVISIONS Definition of Terms Used in This Subchapter § 90.10-40 Offshore supply vessels. (a) An offshore..., supplies or equipment in support of exploration, exploitation, or production of offshore mineral or...

  11. 46 CFR 126.170 - Carriage of offshore workers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Carriage of offshore workers. 126.170 Section 126.170 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS INSPECTION AND CERTIFICATION General § 126.170 Carriage of offshore workers. (a) Offshore workers may be carried aboard an...

  12. Offshore drilling, construction: Fortunes tied to stable gas prices

    SciTech Connect

    Pagano, S.S.; Marsh, T.

    1993-01-01

    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.

  13. Offshore drilling to increase in 1984

    SciTech Connect

    Not Available

    1984-05-01

    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.

  14. Post-breakup Basin Evolution along the South-Atlantic Margins in Brazil and Angola/Namibia

    NASA Astrophysics Data System (ADS)

    Kukla, P. A.; Strozyk, F.; Back, S.

    2013-12-01

    The post-breakup tectono-stratigraphic evolution of large offshore basins along the South American and African continental margins record strongly varying post-rift sedimentary successions. The northernmost segment of the South Atlantic rift and salt basins is characterized by a pronounced asymmetry, with the Brazilian margin comprising narrower and deeper rift basins with less salt in comparison to the Congo-Gabon conjugate margin. Another important observation is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. A regional comparison based on tectonic-stratigraphic analysis of selected seismic transects between the large basins offshore southern Brazil (Espirito Santo Basin, Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Lower Congo Basin, Kwanza Basin, Namibe Basin, Walvis Basin) provides a comprehensive basin-to-basin documentation of the key geological parameters controlling ocean and continental margin development. This comparison includes the margin configuration, subsidence development through time, sediment influx and storage patterns, type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems) and finally major tectonic and magmatic events. Data from the salt basins indicate that salt-related tectonic deformation is amongst the prime controls for the non-uniform post-rift margin development. The diversity in the stratigraphic architecture of the conjugate margins offshore southern Brazil, Namibia and Angola reflects variations in the interplay of a number of controlling factors, of which the most important are (a) the structural configuration of each margin segment at the time of break-up, (b) the post break-up subsidence history of the respective margin segment

  15. Salt deformation history and postsalt structural trends, offshore southern Gabon, West Africa

    SciTech Connect

    Liro, L.M.; Coen, R.

    1996-12-31

    Salt deformation in offshore southern Gabon is represented by mobilization of an Aptian salt layer in reaction to Tertiary clastic progradation. Seismic mapping of salt bodies and associated faulting has resulted in increased understanding of the types and distribution of these salt bodies, their associated faulting patterns, and some aspects of their origin. Away from the Tertiary depocenter, the growth history of salt swells or pillows can be determined by examining onlapping and draping seismic reflectors. Significant Tertiary clastic progradation into the area mobilized the salt and resulted in a series of linear, deep salt walls and asymmetric, basinward-dipping salt rollers, commonly associated with significant up-to-basin faulting dominates the southern Gabon subbasin. The expansion history of associated sediments suggests that these faults expanded episodically throughout the Tertiary, continuing to present-day bathymetric fault scarps. The bias toward up-to-basin faults, to the apparent exclusion of down-to-basin expansion faults, remains enigmatic.

  16. Synchronous onset of the Messinian evaporite precipitation: First Mediterranean offshore evidence

    NASA Astrophysics Data System (ADS)

    Ochoa, Diana; Sierro, Francisco J.; Lofi, Johanna; Maillard, Agnès; Flores, Jose-Abel; Suárez, Mercedes

    2015-10-01

    The Messinian Salinity Crisis (MSC) was a major ecological crisis affecting shallow and deep-water settings over the entire Mediterranean basin. However, the evolution of the MSC and its ecological impacts have mainly been explained on the basis of sediments from onshore outcrops. Lack of complete and physically connected records from onshore and offshore settings has inhibited comprehensive understanding of basin behaviour during the MSC. Herein we present a continuous record from an intermediate-depth basin on the Balearic Promontory that comprises late Tortonian-Messinian marls and evaporitic beds from the first MSC phase (i.e., Primary Lower Gypsum-PLG stage). Well-log and biostratigraphic data allow us establishing a large-scale calibration to the astronomical solutions, and to correlate pre-MSC sediments with classical rhythmic successions outcropping onshore. Thickness and characteristic sedimentary patterns observed in the offshore evaporitic records resemble those from marginal PLG sequences. Furthermore, seismic reflectors from a Bedded Unit (BU), which corresponds to an evaporitic interval according to well-to-seismic ties, are correlated with the onshore PLG sequences. This correlation constitutes the first attempt to link well-known marginal sequences with intermediate-depth offshore settings, which have previously only been studied through seismic imaging. Our time-calibration provides direct evidence supporting a synchronous onset of the PLG phase between onshore and offshore settings along the southwestern Balearic Promontory margin. Those BU reflectors, which were positively correlated to the PLG, were likely precipitated offshore the continental shelf at Messinian times. These results suggest that gypsum precipitation and/or preservation was not always limited to 200 m water-depths and could occur in non-silled basins. Finally, we only found a major erosion at the top of the PLG sequences, implying that the MSC drawdown occurred after the

  17. Changes in the nearshore and offshore zooplankton communities in Lake Ontario: 1981-88

    USGS Publications Warehouse

    Johannsson, Ora E.; Mills, Edward L.; O'Gorman, Robert

    1991-01-01

    We examined trends and factors influencing changes in nearshore and offshore zooplankton abundance and composition in Lake Ontario between 1981 and 1988. In the nearshore (southshore and eastern basin), zooplankton abundance decreased and shifts occurred in the relative abundances of Bosmina longirostris and Daphnia retrocurva (eastern basin) and Daphnia retrocurva and Daphnia galeata mendotae (southshore). These changes could have resulted from increased vertebrate predation or reduced food resources which intensified the effects of predation. In the offshore, the first appearance (FA) of the larger, less common cladoceran species occurred earlier in the season as of 1985. FA was correlated with cumulative epilimnetic temperature (CET) and the catch per unit effort (CPUE) of alewife (Alosa pseudoharengus) a?Y165 mm caught in U.S. waters in the spring. In 1987, when CET was high and CPUE of alewife a?Y165 mm was low, large populations of these cladocerans developed in June and July. Bythotrephes cederstroemi, a recent invader in the Great Lakes, was abundant only in 1987 when the CPUE of alewife was lowest. Changes in zooplankton abundance, development, and composition along the nearshore-offshore gradient reflected effects of temperature, habitat, and planktivory on the community.

  18. 17 CFR 230.135e - Offshore press conferences, meetings with issuer representatives conducted offshore, and press...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... RULES AND REGULATIONS, SECURITIES ACT OF 1933 General § 230.135e Offshore press conferences, meetings... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Offshore press conferences, meetings with issuer representatives conducted offshore, and press-related materials released offshore....

  19. Parana basin

    SciTech Connect

    Zalan, P.V.; Wolff, S.; Conceicao, J.C.J.; Vieira, I.S.; Astolfi, M.A.; Appi, V.T.; Zanotto, O.; Neto, E.V.S.; Cerqueira, J.R.

    1987-05-01

    The Parana basin is a large intracratonic basin in South America, developed entirely on continental crust and filled with sedimentary and volcanic rocks ranging in age from Silurian to Cretaceous. It occupies the southern portion of Brazil (1,100,000 km/sup 2/ or 425,000 mi/sup 2/) and the eastern half of Paraguay (100,000 km/sup 2/ or 39,000 mi/sup 2/); its extension into Argentina and Uruguay is known as the Chaco-Parana basin. Five major depositional sequences (Silurian, Devonian, Permo-Carboniferous, Triassic, Juro-Cretaceous) constitute the stratigraphic framework of the basin. The first four are predominantly siliciclastic in nature, and the fifth contains the most voluminous basaltic lava flows of the planet. Maximum thicknesses are in the order of 6000 m (19,646 ft). The sequences are separated by basin wide unconformities related in the Paleozoic to Andean orogenic events and in the Mesozoic to the continental breakup and sea floor spreading between South America and Africa. The structural framework of the Parana basin consists of a remarkable pattern of criss-crossing linear features (faults, fault zones, arches) clustered into three major groups (N45/sup 0/-65/sup 0/W, N50/sup 0/-70/sup 0/E, E-W). The northwest- and northeast-trending faults are long-lived tectonic elements inherited from the Precambrian basement whose recurrent activity throughout the Phanerozoic strongly influenced sedimentation, facies distribution, and development of structures in the basin. Thermomechanical analyses indicate three main phases of subsidence (Silurian-Devonian, late Carboniferous-Permian, Late Jurassic-Early Cretaceous) and low geothermal gradients until the beginning of the Late Jurassic Permian oil-prone source rocks attained maturation due to extra heat originated from Juro-Cretaceous igneous intrusions. The third phase of subsidence also coincided with strong tectonic reactivation and creation of a third structural trend (east-west).

  20. Offshore oil in the Alaskan Arctic

    NASA Technical Reports Server (NTRS)

    Weeks, W. F.; Weller, G.

    1984-01-01

    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.

  1. Proceedings of offshore and arctic operations, 1992

    SciTech Connect

    Tawfik, A.S. ); Attia, F.G. )

    1992-01-01

    This book contains the proceeding of the offshore and Arctic operations. Topics included are: Pile driving; Flexible pipes; QA/QC Requirements; Oil and gas exploitations and Off shore well-log analysis.

  2. Engineering Challenges for Floating Offshore Wind Turbines

    SciTech Connect

    Butterfield, S.; Musial, W.; Jonkman, J.; Sclavounos, P.

    2007-09-01

    The major objective of this paper is to survey the technical challenges that must be overcome to develop deepwater offshore wind energy technologies and to provide a framework from which the first-order economics can be assessed.

  3. Requirements for construction of offshore concrete platforms

    SciTech Connect

    Gudmestad, O.T.; Pollard, N.

    1994-12-31

    For development of offshore fields, the operator must select production concepts. As several options like subsea templates, floating production and storage concepts, semisubmersibles and steel platforms etc. are available, this paper will review the specifics of one of the possible concepts, the concrete platform. The application of offshore concrete platforms is gaining renewed interest world wide. Several operators are presently carrying out comparisons between offshore concrete structures and jacket support structures. This evaluation includes considerations related to constructability incorporating studies of potential construction sites, and infrastructures as well as availability of materials. This paper summarizes requirements for carrying out an offshore concrete platform construction project and will be useful to those interested in concrete projects.

  4. An example of hybrid petroleum system in offshore Angola

    SciTech Connect

    Duval, B.C.; De Janvry, C.; Heidmann, G.

    1995-08-01

    Block 2 is located on the western Lower Congo basin, in offshore Angola. In the Pinda Album carbonate reservoirs, oil was often found together with gas and gas content generally increases westwards. The Pinda structures are related to the Aptian halokinesis resulting in the segmentation of the Pinda carbonate platform into allochthonous blocks (rafts). Three main source-rocks were identified. Strong source potential was locally observed in the lacustrine Pre-salt Bucomazi equivalent. The major pan of this section is presently in the gas window. The principal marine source-rock is restricted to the upper part of the labe formation (mainly Senonian and Paleocere). The lithe is in the oil kitchen over most of the western part of the block. The Tertiary Malembo marine section has a gas and condensate potential in the westernmost area of the block (Miocene trough). Oil tested in the Pinda formation belongs to two groups. Oils from the easternmost part of the block are of pure lacustrine origin and were generated in the Pre-salt. All the other oils have a mixed origin (Iabe and Pre-salt). Basin modelling was performed to assess the timing of generation and migration and the migration paths. The development of overpressure at the boundary between the Malembo and the labe controls the hydrocarbon migration.

  5. New perspectives in offshore wind energy.

    PubMed

    Failla, Giuseppe; Arena, Felice

    2015-02-28

    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

  6. 2014 Offshore Wind Market and Economic Analysis

    SciTech Connect

    Hamilton, Bruce

    2014-08-25

    The objective of this report is to provide a comprehensive annual assessment of the U.S. offshore wind market.This 3rd annual report focuses on new developments that have occurred in 2014. The report provides stakeholders with a reliable and consistent data source addressing entry barriers and U.S. competitiveness in the offshore wind market. Available for download are both the full report and the report's underlying data.

  7. New perspectives in offshore wind energy

    PubMed Central

    Failla, Giuseppe; Arena, Felice

    2015-01-01

    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

  8. Medical evacuations from offshore structures.

    PubMed

    Norman, J N; Ballantine, B N; Brebner, J A; Brown, B; Gauld, S J; Mawdsley, J; Roythorne, C; Valentine, M J; Wilcock, S E

    1988-09-01

    A retrospective study was carried out on medical evacuations from the installations of four major oil or gas producing companies, or both, operating offshore on the United Kingdom continental shelf. The study covered 1976-84 during which 2162 evacuations were recorded. Of these, 137 (7.7%) required the use of a chartered helicopter. In the earlier years of the study there were substantially more injuries sustained than episodes of illness recorded but from 1980 onwards the cases of illness equalled those of injury. Using the International Classification of Diseases, the digestive system was responsible for most evacuations for illness and of those, about half (115 evacuations) were for dental problems. Suspected fractures were responsible for about one third of those evacuated for an injury but injuries of hands and eye conditions were particularly common, accounting for 25% of all evacuations. As the age of the evacuee increased the proportion of evacuations for injury decreased and that for illness increased. The mean age for evacuation for injury was 28.3 years and for illness 34.4 years. Few evacuations were required for those aged over 45. PMID:3179237

  9. Offshore oil and the coastline

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    A radical, accelerated 5-year plan to offer 875 million acres (of which 20 million could actually be leased for oil and gas extraction purposes) on the outer continental shelf (OCS) could result in the release of large volumes of drilling wastes and spillage (Environ. Sci. Tech., Nov. 1981). The actual leasing, under the 5-year plan proposed by Secretary of the Interior James G. Watt, could amount to 4-5 million acres per year—about 10 times as much, on the average, as had been leased over the past 25 years. Regulations on the environmental effects may be less complicated yet more effective in that impact statements will cover large areas instead of the tract-by-tract statements now required. A number of the new offshore leasing areas, for example, the Alaska Coast (Cook Inlet, Beaufort Bay, Gulf of Alaska), the Blake Plateau and Baltimore Canyon, and the Georges Bank, are extremely valuable in terms of renewable resources and potentially fragile in terms of environmental conditions. Fishing interests in these areas have produced considerable controversy over the planned sale of petroleum rights.

  10. Arctic & Offshore Technical Data System

    Energy Science and Technology Software Center (ESTSC)

    1990-07-01

    AORIS is a computerized information system to assist the technology and planning community in the development of Arctic oil and gas resources. In general, AORIS is geographically dependent and, where possible, site specific. The main topics are sea ice, geotechnology, oceanography, meteorology, and Arctic engineering, as they relate to such offshore oil and gas activities as exploration, production, storage, and transportation. AORIS consists of a directory component that identifies 85 Arctic energy-related databases and tellsmore » how to access them; a bibliographic/management information system or bibliographic component containing over 8,000 references and abstracts on Arctic energy-related research; and a scientific and engineering information system, or data component, containing over 800 data sets, in both tabular and graphical formats, on sea ice characteristics taken from the bibliographic citations. AORIS also contains much of the so-called grey literature, i.e., data and/or locations of Arctic data collected, but never published. The three components are linked so the user may easily move from one component to another. A generic information system is provided to allow users to create their own information systems. The generic programs have the same query and updating features as AORIS, except that there is no directory component.« less

  11. Structure and geologic history of late Cenozoic Eel River basin, California

    SciTech Connect

    Clarke, S.H. Jr.

    1988-03-01

    The Eel River basin formed as a late Cenozoic forearc basin floored by late Mesozoic and early Cenozoic allochthonous terranes (central and coastal belts of the Franciscan complex). Regionally, basement rocks are unconformably overlain on land by a sedimentary sequence as much as about 4200 m thick that comprises the Bear River Formation (early and middle Miocene) and the Wildcat Group (late Miocene to middle Pleistocene) and offshore by broadly coeval upper Tertiary and Quaternary deposits as much as 3300 m thick. Offshore, the southern part of the basin is typified by the seaward extensions of youthful northeast-dipping thrust and reverse faults and northwest-trending anticlines. The latest period of deformation in this part of the basin began during the middle Pleistocene and probably reflects north-northwestward migration of the Mendocino triple junction and encroachment of the Pacific plate. Farther north, the western basin margin and adjacent upper continental slope are separated from the axial part of the offshore basin by a narrow zone of north-northwest-trending, right-stepping en echelon folds. These folds indicate that northeast-southwest compression characteristic of the southern part of the basin is accompanied toward the north by right-lateral shear between the accretionary complex to the west and the basin to the east. The northeastern margin of the offshore basin is cut by north to north-northwest-trending high-angle reverse faults that vertically offset basement rocks as much as 1300 m, west side down. These faults, which may merge northward, coincide with older terrane boundaries and locally show evidence of late Cenozoic reactivation with possible right-lateral slip.

  12. 78 FR 27913 - Revision of Crane Regulation Standards for Mobile Offshore Drilling Units (MODUs), Offshore...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-13

    ...The Coast Guard proposes to revise regulations related to the design, certification, inspection, and testing of cranes. These regulations apply to cranes installed on Mobile Offshore Drilling Units (MODUs), Offshore Supply Vessels (OSVs), and floating Outer Continental Shelf (OCS) facilities. This revision would update industry standards incorporated by reference with more recent versions,......

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

    SciTech Connect

    Grover, G. Jr. )

    1993-09-01

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

  14. Distribution and interannual variability of supraglacial lakes on debris-covered glaciers in the Khan Tengri-Tumor Mountains, Central Asia

    NASA Astrophysics Data System (ADS)

    Qiao, Liu; Mayer, Christoph; Liu, Shiyin

    2015-01-01

    Supraglacial lakes are widely formed on debris-covered glaciers in the Khan Tengri-Tumor Mountains (KTTM), Tianshan, Central Asia. Study of their distribution characters based on regional-wide remote sensing investigations is still lacking, but it can promote our understanding about the influence of supraglacial lakes on the surface melting, hydrology and dynamics of debris-covered glaciers in this region. This study presents results of the supraglacial lake inventory in the KTTM region, based on multi-year Landsat images. We focus on the glacio-geomorphological characters of the supraglacial lakes and their late summer conditions, since all suitable Landsat images were acquired between August and September during 1990-2011. With a minimum threshold extent of 3600 m2 for conservative mapping results, we totally mapped 775 supraglacial lakes and 38 marginal glacial lakes on eight huge debris-covered glaciers. Supraglacial lakes are concentrated on the Tumor Glacier and the South Inylchek Glacier, two biggest glaciers in this region. Although most supraglacial lakes are short-lived, a number of lakes can be repeatedly identified between different Landsat images. Detailed investigation of these ‘perennial’ lakes on the Tumor Glacier indicates that their filling frequency and area contributions have increased since 2005. Analysis of the area-elevation distributions for all mapped supraglacial lakes shows that they predominantly occur close to the altitude of 3250 m a.s.l., as high as the lowest reach of clean ice where surface debris begins to appear, and can further develop upglacier to a limit of about 3950 m a.s.l.. Total and mean area of supraglacial lakes in the KTTM region during the late summer seasons show great variability between years. Correlation analysis between the annual lake area and the observed nearby meteorological conditions suggests that warmer springs seem related to the draining of some supraglacial lakes during the following seasons, due to

  15. Tectonic and geodynamic setting of oil and gas basins of the Soviet Union

    SciTech Connect

    Khain, V.E.; Sokolov, B.A. ); Kleshchev, K.A.; Shein, V.S. )

    1991-02-01

    Within the territory of the Soviet Union and its off-shore economic zone are about 70 sedimentary basins containing oil and gas. The basins include almost all basin types described in present-day plate-tectonic classifications, namely (1) intracontinental and pericontinental rifts, suprarift syneclises, and zones of pericratonic downwarps; (2) ancient passive margins of continents with adjacent overthrust fold system; (3) modern passive margins of continents; (4) zones of convergence of lithospheric plates (i.e., zones of subduction of oceanic plates below continental plates); and (5) zones of collision of continental lithospheric plates. So, far, the only type of basin not identified within the territory of the Soviet Union is the pull-apart basin. The location and distribution of oil and gas deposits in the section of a basin, prevailing types of traps, and scale of potential resources are all features influenced by the geodynamic type of the basin.

  16. New OBS network deployment offshore Ireland

    NASA Astrophysics Data System (ADS)

    Le Pape, Florian; Bean, Chris; Craig, David; Jousset, Philippe; Horan, Clare; Hogg, Colin; Donne, Sarah; McCann, Hannah; Möllhoff, Martin; Kirk, Henning; Ploetz, Aline

    2016-04-01

    With the presence of the stormy NE Atlantic, Ireland is ideally located to investigate further our understanding of ocean generated microseisms and use noise correlation methods to develop seismic imaging in marine environments as well as time-lapse monitoring. In order to study the microseismic activity offshore Ireland, 10 Broad Band Ocean Bottom Seismographs (OBSs) units including hydrophones have been deployed in January 2016 across the shelf offshore Donegal and out into the Rockall Trough. This survey represents the first Broadband passive study in this part of the NE Atlantic. The instruments will be recovered in August 2016 providing 8 months worth of data to study microseisms but also the offshore seismic activity in the area. One of the main goal of the survey is to investigate the spatial and temporal distributions of dominant microseism source regions, close to the microseism sources. Additionally we will study the coupling of seismic and acoustic signals at the sea bed and its evolution in both the deep water and continental shelf areas. Furthermore, the survey also aims to investigate further the relationship between sea state conditions (e.g. wave height, period), seafloor pressure variations and seismic data recorded on both land and seafloor. Finally, the deployed OBS network is also the first ever attempt to closely monitor local offshore earthquakes in Ireland. Ireland seismicity although relatively low can reduce slope stability and poses the possibility of triggering large offshore landslides and local tsunamis.

  17. Operational management of offshore energy assets

    NASA Astrophysics Data System (ADS)

    Kolios, A. J.; Martinez Luengo, M.

    2016-02-01

    Energy assets and especially those deployed offshore are subject to a variety of harsh operational and environmental conditions which lead to deterioration of their performance and structural capacity over time. The aim of reduction of CAPEX in new installations shifts focus to operational management to monitor and assess performance of critical assets ensuring their fitness for service throughout their service life and also to provide appropriate and effective information towards requalification or other end of life scenarios, optimizing the OPEX. Over the last decades, the offshore oil & gas industry has developed and applied various approaches in operational management of assets through Structural Health and Condition Monitoring (SHM/CM) systems which can be, at a certain level, transferable to offshore renewable installations. This paper aims to highlight the key differences between offshore oil & gas and renewable energy assets from a structural integrity and reliability perspective, provide a comprehensive overview of different approaches that are available and applicable, and distinguish the benefits of such systems in the efficient operation of offshore energy assets.

  18. A framework for offshore vendor capability development

    NASA Astrophysics Data System (ADS)

    Yusuf Wibisono, Yogi; Govindaraju, Rajesri; Irianto, Dradjad; Sudirman, Iman

    2016-02-01

    Offshore outsourcing is a common practice conducted by companies, especially in developed countries, by relocating one or more their business processes to other companies abroad, especially in developing countries. This practice grows rapidly owing to the ease of accessing qualified vendors with a lower cost. Vendors in developing countries compete more intensely to acquire offshore projects. Indonesia is still below India, China, Malaysia as main global offshore destinations. Vendor capability is among other factors that contribute to the inability of Indonesian vendor in competing with other companies in the global market. Therefore, it is essential to study how to increase the vendor's capability in Indonesia, in the context of global offshore outsourcing. Previous studies on the vendor's capability mainly focus on capabilities without considering the dynamic of capabilities due to the environmental changes. In order to be able to compete with competitors and maintain the competitive advantage, it is necessary for vendors to develop their capabilities continuously. The purpose of this study is to develop a framework that describes offshore vendor capability development along the client-vendor relationship stages. The framework consists of three main components, i.e. the stages of client-vendor relationship, the success of each stage, and the capabilities of vendor at each stage.

  19. Offshore oil gas trends in ROVs tooling

    SciTech Connect

    Jacobson, J.R. )

    1994-04-01

    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.

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

    SciTech Connect

    Francois, D.K.

    1994-12-31

    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.

  1. Solar power satellite offshore rectenna study

    NASA Technical Reports Server (NTRS)

    1980-01-01

    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.

  2. Greece licensing round to focus on western sedimentary basins

    SciTech Connect

    Roussos, N.; Marnelis, F. )

    1995-03-06

    New opportunities for international oil companies to explore for hydrocarbons in Greece will emerge shortly. Parliament ratified a new petroleum law in January 1995, and DEP-EKY SA will undertake an international licensing round for offshore-onshore areas mainly in western Greece during second half 1995. The paper describes the fold and thrust belt of western Greece; the Katakolon oil field; the tertiary basins of eastern Greece; the Prinos and Prinos North oil fields; and the Epanomi gas field.

  3. National Offshore Wind Energy Grid Interconnection Study Full Report

    SciTech Connect

    Daniel, John P.; Liu, Shu; Ibanez, Eduardo; Pennock, Ken; Reed, Gregory; Hanes, Spencer

    2014-07-30

    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.

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

    SciTech Connect

    Not Available

    2012-02-01

    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.

  5. National Offshore Wind Energy Grid Interconnection Study Executive Summary

    SciTech Connect

    Daniel, John P.; Liu, Shu; Ibanez, Eduardo; Pennock, Ken; Reed, Gregory; Hanes, Spencer

    2014-07-30

    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.

  6. Offshore-platform decommissioning perceptions change

    SciTech Connect

    Twachtman, R.

    1997-12-08

    The oil and gas industry has seen a change in the perceptions about decommissioning offshore facilities. Now, decommissioning projects are being planned ahead of actual field development, and new concepts derived during decommissioning often are used to provide feedback for new development projects. The current trends and concepts applicable to decommissioning can be summarized as: advanced planning; engineered solutions; research and development; reuse; expanded use of offshore reefs; and deepwater disposal. Planning the platform decommissioning ahead of time (at least 2 years before production ceases) is key to a safe, environmentally conscious, and efficient decommissioning project. The paper discusses decommissioning projects, engineered solutions, research and development; reuse of platforms, and deepwater disposal.

  7. Regional method to assess offshore slope stability.

    USGS Publications Warehouse

    Lee, H.J.; Edwards, B.D.

    1986-01-01

    The slope stability of some offshore environments can be evaluated by using only conventional acoustic profiling and short-core sampling, followed by laboratory consolidation and strength testing. The test results are synthesized by using normalized-parameter techniques. The normalized data are then used to calculate the critical earthquake acceleration factors or the wave heights needed to initiate failure. These process-related parameters provide a quantitative measure of the relative stability for locations from which short cores were obtained. The method is most applicable to offshore environments of gentle relief and simple subsurface structure and is not considered a substitute for subsequent site-specific analysis. -from ASCE Publications Information

  8. Buried Mesozoic rift basins of the U. S. middle Atlantic continental margin

    SciTech Connect

    Benson, R.N. )

    1991-08-01

    The Atlantic continental margin is one of the frontier areas for oil and gas exploration in the US. Most the activity has been offshore where Upper Jurassic-Lower Cretaceous siliciclastic and carbonate rocks have been the drilling objectives, with only one significant but noncommercial gas discover. Onshore, recent exploration activities have focused on early Mesozoic rift basins buried beneath the postrift sediments of the middle Atlantic coastal plain. Many of the basins are of interest because they contain fine-grained lacustrine rocks that have sufficient organic richness, if not lost through hydrocarbon generation, to be classified as source beds for oil or gas. Locations of inferred rift basins beneath the middle Atlantic coastal plain were determined by analysis of drill-hole data in combination with gravity anomaly and aeromagnetic maps. Two basins in Delaware and the Queen Anne basin of Maryland are imaged on a regional Vibroseis profile. Areas enclosing inferred rift basins in the offshore region were mapped from interpretation of seismic reflection profiles. Assuming that petroleum source beds are present in the basin (synrift) rocks, hydrocarbon-generation models (Lopatin method) indicate that for a basin just offshore Delaware that is buried by 7 km of postrift sediments, only dry gas would be present in reservoir rocks; for the Norfolk basin of the Virginia coast buried by only 3 km of postrift rocks, the upper few hundred meters of synrift rocks are still within the oil-generation window. The less deeply buried basins beneath the coastal plain likely are still within the oil window.

  9. Boundary Spanning in Offshored Information Systems Development Projects

    ERIC Educational Resources Information Center

    Krishnan, Poornima

    2010-01-01

    Recent growth in offshore outsourcing of information systems (IS) services is accompanied by managing the offshore projects successfully. Much of the project failures can be attributed to geographic and organizational boundaries which create differences in culture, language, work patterns, and decision making processes among the offshore project…

  10. 47 CFR 22.1007 - Channels for offshore radiotelephone systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Channels for offshore radiotelephone systems. 22.1007 Section 22.1007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Offshore Radiotelephone Service § 22.1007 Channels for offshore radiotelephone systems. The channels listed in...

  11. 76 FR 24504 - National Offshore Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-02

    ... SECURITY National Offshore Safety Advisory Committee AGENCY: United States Coast Guard, DHS. ACTION: Committee Management; Notice of Federal Advisory Committee Meeting. SUMMARY: The National Offshore Safety... Federal Advisory Committee Act, 5 U.S.C. App. (Pub. L. 92-463). The National Offshore Safety...

  12. 78 FR 18618 - National Offshore Safety Advisory Committee; Vacancies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-27

    ... SECURITY Coast Guard National Offshore Safety Advisory Committee; Vacancies AGENCY: United States Coast... Offshore Safety Advisory Committee (NOSAC). NOSAC advises the Secretary of the Department of Homeland... exploration of offshore mineral and energy resources insofar as they relate to matters within Coast...

  13. International Offshore Students' Perceptions of Virtual Office Hours

    ERIC Educational Resources Information Center

    Wdowik, Steven; Michael, Kathy

    2013-01-01

    Purpose: The main aim of this study is to gauge international offshore students' perceptions of virtual office hours (VOH) to consult with their offshore unit coordinators in Australia. Design/methodology/approach: This paper employs a quantitative and qualitative approach where data was sourced from three offshore campuses over a 12-month period…

  14. United States Offshore Wind Resource Assessment

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    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

  15. The limits of seaward spreading and slope instability at the continental margin offshore Mt Etna, imaged by high-resolution 2D seismic data

    NASA Astrophysics Data System (ADS)

    Gross, Felix; Krastel, Sebastian; Geersen, Jacob; Behrmann, Jan Hinrich; Ridente, Domenico; Chiocci, Francesco Latino; Bialas, Jörg; Papenberg, Cord; Cukur, Deniz; Urlaub, Morelia; Micallef, Aaron

    2016-01-01

    Mount Etna is the largest active volcano in Europe. Instability of its eastern flank is well documented onshore, and continuously monitored by geodetic and InSAR measurements. Little is known, however, about the offshore extension of the eastern volcano flank, defining a serious shortcoming in stability models. In order to better constrain the active tectonics of the continental margin offshore the eastern flank of the volcano, we acquired a new high-resolution 2D reflection seismic dataset. The data provide new insights into the heterogeneous geology and tectonics at the continental margin offshore Mt Etna. The submarine realm is characterized by different blocks, which are controlled by local- and regional tectonics. A compressional regime is found at the toe of the continental margin, which is bound to a complex basin system. Both, the clear link between on- and offshore tectonic structures as well as the compressional regime at the easternmost flank edge, indicate a continental margin gravitational collapse as well as spreading to be present at Mt Etna. Moreover, we find evidence for the offshore southern boundary of the moving flank, which is identified as a right lateral oblique fault north of Catania Canyon. Our findings suggest a coupled volcano edifice/continental margin instability at Mt Etna, demonstrating first order linkage between on- and offshore tectonic processes.

  16. Lake Michigan Offshore Wind Feasibility Assessment

    SciTech Connect

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

    2014-06-30

    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

  17. Petroleum systems of the Northwest Java Province, Java and offshore southeast Sumatra, Indonesia

    USGS Publications Warehouse

    Bishop, Michele G.

    2000-01-01

    Mature, synrift lacustrine shales of Eocene to Oligocene age and mature, late-rift coals and coaly shales of Oligocene to Miocene age are source rocks for oil and gas in two important petroleum systems of the onshore and offshore areas of the Northwest Java Basin. Biogenic gas and carbonate-sourced gas have also been identified. These hydrocarbons are trapped primarily in anticlines and fault blocks involving sandstone and carbonate reservoirs. These source rocks and reservoir rocks were deposited in a complex of Tertiary rift basins formed from single or multiple half-grabens on the south edge of the Sunda Shelf plate. The overall transgressive succession was punctuated by clastic input from the exposed Sunda Shelf and marine transgressions from the south. The Northwest Java province may contain more than 2 billion barrels of oil equivalent in addition to the 10 billion barrels of oil equivalent already identified.

  18. Evaluating the Contribution of Nearshore Offshore Exchange to Lake Superior Warming

    NASA Astrophysics Data System (ADS)

    McKinney, P. J.; Matsumoto, K.

    2014-12-01

    Lake Superior is one of the largest lakes in the world and provides important benefits such as clean water, recreation, and waterway transportation between neighboring communities in the U.S. and Canada. Temperatures recorded at mid-lake buoys indicate the date of annual summer stratification is arriving earlier and surface temperatures are increasing. In this study, we use a realistically configured, 3D model of Lake Superior to characterize the exchange of nearshore waters with offshore waters and evaluate the hypothesis that warmer coastal waters, transported offshore, contribute to warming the surface waters of the central lake basin. There are relatively few studies on Superior's circulation and it is unclear how long nearshore waters remain along the coast, an important timescale influencing the lake's water quality and biogeochemistry. Preliminary results indicate that nearshore waters have months-long residence time in select locations along the southern coast where coastline and bottom slope seem to favor sluggish circulation. Nearshore-offshore exchange occurs rapidly when counterclockwise coastal circulation sets in during the summer stratified period. We assess the contribution of this exchange to lake-wide surface temperatures and biogeochemistry.

  19. The offshore East African Rift System: Structural framework at the toe of a juvenile rift

    NASA Astrophysics Data System (ADS)

    Franke, Dieter; Jokat, Wilfried; Ladage, Stefan; Stollhofen, Harald; Klimke, Jennifer; Lutz, Ruediger; Mahanjane, Estevão. Stefane; Ehrhardt, Axel; Schreckenberger, Bernd

    2015-10-01

    The Cenozoic East African Rift System (EARS) extends from the Red Sea to Mozambique. Here we use seismic reflection and bathymetric data to investigate the tectonic evolution of the offshore branch of the EARS. The data indicate multiple and time transgressive neotectonic deformations along ~800 km of the continental margin of northern Mozambique. We observe a transition from a mature rift basin in the north to a juvenile fault zone in the south. The respective timing of deformation is derived from detailed seismic stratigraphy. In the north, a ~30 km wide and more than 150 km long, N-S striking symmetric graben initiated as half-graben in the late Miocene. Extension accelerated in the Pliocene, causing a continuous conjugate border fault and symmetric rift graben. Coevally, the rift started to propagate southward, which resulted in a present-day ~30 km wide half-graben, approximately 200 km farther south. Since the Pleistocene, the rift has continued to propagate another ~300 km, where the incipient rift is reflected by subrecent small-scale normal faulting. Estimates of the overall brittle extension of the matured rift range between 5 and 12 km, with an along-strike southward decrease of the extension rate. The offshore portion of the EARS evolves magma poor, similar to the onshore western branch. The structural evolution of the offshore EARS is suggested to be related to and controlled by differing inherited lithospheric fabrics. Preexisting fabrics may not only guide and focus extension but also control rift architecture.

  20. Observations of the Eastern Maine Coastal Current and its offshore extensions in 1994

    NASA Astrophysics Data System (ADS)

    Pettigrew, Neal R.; Townsend, David W.; Xue, Huijie; Wallinga, John P.; Brickley, Peter J.; Hetland, Robert D.

    1998-12-01

    Cold surface temperatures, reflecting Scotian Shelf origins and local tidal mixing, serve as a tracer of the Eastern Maine Coastal Current and its offshore extensions, which appear episodically as cold plumes erupting from the eastern Maine shelf. A cold water plume emanating from the Eastern Maine Coastal Current in May 1994 was investigated using advanced very high resolution radiometer (AVHRR) imagery, shipboard surveys of physical and biochemical properties, and satellite-tracked drifters. Evidence is presented that suggests that some of the plume waters were entrained within the cyclonic circulation over Jordan Basin, while the major portion participated in an anticyclonic eddy at the distal end of the plume. Calculations of the nitrate transported offshore by the plume show that this feature can episodically export significant quantities of nutrients from the Eastern Maine Coastal Current to offshore regions that are generally nutrient depleted during spring-summer. A series of AVHRR images is used to document the seasonal along-shelf progression of the coastal plume separation point. We speculate on potential causes and consequences of plume separation from the coastal current and suggest that this feature may be an important factor influencing the patterns and overall biological productivity of the eastern Gulf of Maine.

  1. Built-up of the continental margin offshore Central Mozambique from marine geophysical investigations

    NASA Astrophysics Data System (ADS)

    Heyde, I.; Block, M.; Ehrhardt, A.; Reichert, C. J.; Schreckenberger, B.

    2009-12-01

    In September/October 2007, along with institutes from Germany, France and Portugal BGR conducted the cruise MoBaMaSis (Mozambique Basin Marine Seismic Survey) using RV MARION DUFRESNE. The goal of the marine geophysical measurements offshore central Mozambique was the investigation of the continental margin in terms of its structure and formation history with special focus on the opening history of Eastern Gondwana and the hydrocarbon potential. A total of four long transects (450 to 225 km long) and a number of connection lines were acquired from the shelf and the slope into the deep Mozambique Basin. The data comprises multichannel seismic reflection (MCS), magnetic, gravimetric and swath bathymetry. On the eastern two transects two on-/offshore seismic refraction studies were carried out. Apart from results of the MCS and the magnetic work, in particular the results of the gravity data are presented. A 3D density model was developed. In the Mozambique Basin a large thick sedimentary succession of up to 8 km thickness from Jurassic to present is observed. Two deep reaching wells supported, at least in part, the identification of stratigraphy. Faint indications for SDR sequences related to volcanic flows are found in the northern part of the study area. In the south, the Beira High represents a prominent structure. The basement high with sediments of considerable reduced thickness is characterized by a distinct gravity minimum. A possible explanation is that the high is formed by a continental fragment. In addition, no clear magnetic chrons are identifiable. Thus, stretched continental crust is assumed underlying this part of the Mozambique Basin.

  2. Cut drydocking costs for offshore rigs

    SciTech Connect

    Albaugh, E.K.

    1985-07-01

    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.

  3. 31 CFR 544.406 - Offshore transactions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Offshore transactions. 544.406 Section 544.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY WEAPONS OF MASS DESTRUCTION PROLIFERATORS...

  4. 31 CFR 544.406 - Offshore transactions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Offshore transactions. 544.406 Section 544.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY WEAPONS OF MASS DESTRUCTION PROLIFERATORS...

  5. 31 CFR 544.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 544.406 Section 544.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY WEAPONS OF MASS DESTRUCTION...

  6. 31 CFR 544.406 - Offshore transactions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Offshore transactions. 544.406 Section 544.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY WEAPONS OF MASS DESTRUCTION PROLIFERATORS...

  7. 31 CFR 544.406 - Offshore transactions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Offshore transactions. 544.406 Section 544.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY WEAPONS OF MASS DESTRUCTION PROLIFERATORS...

  8. 31 CFR 576.407 - Offshore transactions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Offshore transactions. 576.407 Section 576.407 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRAQ STABILIZATION AND INSURGENCY SANCTIONS...

  9. 31 CFR 576.407 - Offshore transactions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Offshore transactions. 576.407 Section 576.407 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRAQ STABILIZATION AND INSURGENCY SANCTIONS...

  10. 31 CFR 576.407 - Offshore transactions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Offshore transactions. 576.407 Section 576.407 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRAQ STABILIZATION AND INSURGENCY SANCTIONS...

  11. 31 CFR 576.407 - Offshore transactions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Offshore transactions. 576.407 Section 576.407 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY IRAQ STABILIZATION AND INSURGENCY SANCTIONS...

  12. 31 CFR 587.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 587.406 Section 587.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FEDERAL REPUBLIC OF YUGOSLAVIA (SERBIA...

  13. 31 CFR 594.407 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 594.407 Section 594.407 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY GLOBAL TERRORISM SANCTIONS...

  14. Human Rights, Academic Freedom, and Offshore Academics

    ERIC Educational Resources Information Center

    Ross, Andrew

    2011-01-01

    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)…

  15. Planning and evaluation parameters for offshore complexes

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    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.

  16. Solar power satellite offshore rectenna study

    NASA Astrophysics Data System (ADS)

    1980-11-01

    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.

  17. Offshore blowouts, data for risk assessment

    SciTech Connect

    Holand, P.

    1995-12-31

    Blowouts are, besides gas leakages, the major contributor to the total risk for offshore installations. Therefore, the blowout risk is always included in Quantitative Risk Analyses (QRAs) of offshore installations in the Norwegian Sector of the North Sea. SINTEF Offshore Blowout Database has existed since 1984 (until 1990 it was called Marintek`s blowout database). In 1990 the responsibility of the database was transferred to SINTEF Safety and Reliability. Throughout these years the database has been used for assessing blowout risk associated to development and operation of fields offshore Norway. Six oil companies and two consultants are presently sponsoring the database. These companies are using the database when performing risk analyses. During the past three years the database has been subjected to a thorough quality improvement, both with respect to the user interface, and most important, regarding the blowout data included in the database. What is unique with this database, besides the high quality of blowout descriptions, is first that the blowout causes are categorized related to loss of primary and secondary barriers. Secondly that the user interface makes it possible to establish searches to withdraw information regarding any blowout type subjected for specific searches.

  18. 31 CFR 537.406 - Offshore transactions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Offshore transactions. 537.406 Section 537.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY BURMESE SANCTIONS REGULATIONS Interpretations §...

  19. 31 CFR 541.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 541.406 Section 541.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ZIMBABWE SANCTIONS REGULATIONS...

  20. Efficient high-permeability fracturing offshore

    SciTech Connect

    Phillipi, M.; Farabee, M.

    1996-12-31

    Offshore operators can more efficiently and effectively perform high-permeability and conventional hydraulic fracture treatments by blending treatment slurries under microprocessor control, adding undiluted acid on-the-fly, and altering sand concentrations and other slurry properties instantaneously. A two-skid system has been designed with these considerations in mind. The system, which can be shipped efficiently in ISO containers, has been tested on fluids up to 210-cp viscosity and can step or ramp sand concentrations up to a maximum of 20 lb/gal. All additives, including acid treatments, are added on-the-fly; leftover additives and acids may be stored for future jobs. The system may be applied in most conditions, including offshore wells requiring conventional or high-permeability fracture treatments and certain land-based wells in remote areas where a compact skid is needed. Three significant benefits have resulted from using the compact-skid system: offshore operators have been able to ship the skid system at 20% of shipping costs of non-ISO equipment; on-the-fly mixing has prevented material waste associated with batch-mixing; and volumes pumped on actual jobs have closely matched job designs. Data have been collected from several Gulf of Mexico jobs run with the two-part skid system that has been designed for conducting hydraulic fracture treatments from offshore rigs.

  1. 31 CFR 548.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 548.406 Section 548.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY BELARUS SANCTIONS REGULATIONS...

  2. 31 CFR 593.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 593.406 Section 593.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FORMER LIBERIAN REGIME OF CHARLES...

  3. 31 CFR 593.406 - Offshore transactions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Offshore transactions. 593.406 Section 593.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FORMER LIBERIAN REGIME OF CHARLES TAYLOR...

  4. Solar power satellite offshore rectenna study

    NASA Technical Reports Server (NTRS)

    1980-01-01

    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.

  5. 31 CFR 549.406 - Offshore transactions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Offshore transactions. 549.406 Section 549.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY LEBANON SANCTIONS REGULATIONS Interpretations §...

  6. 31 CFR 549.406 - Offshore transactions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Offshore transactions. 549.406 Section 549.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY LEBANON SANCTIONS REGULATIONS Interpretations §...

  7. 31 CFR 549.406 - Offshore transactions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Offshore transactions. 549.406 Section 549.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY LEBANON SANCTIONS REGULATIONS Interpretations §...

  8. 31 CFR 549.406 - Offshore transactions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Offshore transactions. 549.406 Section 549.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY LEBANON SANCTIONS REGULATIONS Interpretations §...

  9. 31 CFR 537.406 - Offshore transactions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Offshore transactions. 537.406 Section 537.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY BURMESE SANCTIONS REGULATIONS...

  10. 31 CFR 541.406 - Offshore transactions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Offshore transactions. 541.406 Section 541.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ZIMBABWE SANCTIONS REGULATIONS Interpretations §...

  11. 31 CFR 541.406 - Offshore transactions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Offshore transactions. 541.406 Section 541.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ZIMBABWE SANCTIONS REGULATIONS Interpretations §...

  12. 31 CFR 541.406 - Offshore transactions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Offshore transactions. 541.406 Section 541.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ZIMBABWE SANCTIONS REGULATIONS Interpretations §...

  13. 31 CFR 541.406 - Offshore transactions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Offshore transactions. 541.406 Section 541.406 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ZIMBABWE SANCTIONS REGULATIONS Interpretations §...

  14. Offshore Investments by Colleges Draw Scrutiny

    ERIC Educational Resources Information Center

    Fain, Paul; Wolverton, Brad

    2007-01-01

    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…

  15. Basin-mountain structures and hydrocarbon exploration potential of west Junggar orogen in China

    NASA Astrophysics Data System (ADS)

    Wu, X.; Qi, X.; Zheng, M.

    2015-12-01

    Situated in northern Xinjiang, China, in NE-SW trend, West Junggar Orogen is adjacent to Altai fold belt on the north with the Ertix Fault as the boundary, North Tianshan fold belt on the south with the Ebinur Lake Strike-slip Fault as the boundary, and the Junggar Basin on the southeast with Zaire-Genghis Khan-Hala'alat fold belt as the boundary. Covering an area of about 10×104 km2 in China, there are medium and small intermontane basins, Burqin-Fuhai, Tacheng, Hefeng and Hoxtolgay, distributing inside the orogen. Tectonically West Junggar Orogen lies in the middle section of the Palaeo-Asian tectonic domain where the Siberia, Kazakhstan and Tarim Plates converge, and is the only orogen trending NE-SW in the Palaeo-Asian tectonic domain. Since the Paleozoic, the orogen experienced pre-Permian plate tectonic evolution and post-Permian intra-plate basin evolution. Complex tectonic evolution and multi-stage structural superimposition not only give rise to long term controversial over the basin basement property but also complex basin-mountain coupling relations, structures and basin superimposition modes. According to analysis of several kinds of geological and geophysical data, the orogen was dominated by compressive folding and thrust napping from the Siberia plate in the north since the Late Paleozoic. Compressive stress weakened from north to south, corresponding to subdued vertical movement and enhanced horizontal movement of crustal surface from north to south, and finally faded in the overthrust-nappe belt at the northwest margin of the Junggar Basin. The variation in compressive stress is consistent with the surface relief of the orogen, which is high in the north and low in the south. There are two kinds of basin-mountain coupling relationships, i.e. high angle thrusting and overthrusting and napping, and two kinds of basin superimposition modes, i.e. inherited and progressive, and migrating and convulsionary modes. West Junggar orogen has rich oil and gas

  16. Geology of the Eel River basin and adjacent region: implications for late Cenozoic tectonics of the southern Cascadia subduction zone and Mendocino triple junction

    USGS Publications Warehouse

    Clarke, S.H., Jr.

    1992-01-01

    Two upper Cenozoic depositional sequences of principally marine strata about 4000m thick overlie accreted basement terranes of the Central and Coastal belts of the Franciscan Complex in the onshore-offshore Eel River basin of northwestern California. The older depositional sequence is early to middle Miocene in age and represents slope basin and slope-blanket deposition, whereas the younger sequence, late Miocene to middle Pleistocene in age, consists largely of forearc basin deposits. -from Author

  17. The offshore basement of Perú: Evidence for different igneous and metamorphic domains in the forearc

    NASA Astrophysics Data System (ADS)

    Romero, Darwin; Valencia, Kiko; Alarcón, Pedro; Peña, Daniel; Ramos, Victor A.

    2013-03-01

    As a result of new studies carried out in the offshore of Perú during the exploration and hydrocarbon evaluation of the forearc basins, new U-Pb SHRIMP and TIMS in zircons and some Ar-Ar data were obtained in the metamorphic and igneous basement. The understanding of this basement was critical to evaluate different hypotheses that have been proposed for the tectonic evolution of pre-Andean crust of Perú. Recent research performed in the basement rocks of the Marañón Massif in northern Perú, claimed that west of this area was a basement-free region in the Paleozoic, where the arc and forearc were developed in a mafic quasi-oceanic crust. However, petrographic studies and new preliminary ages indicate, for the first time, the nature and age of this sialic basement. Reconnaissance studies were performed in several offshore islands, as the Las Hormigas de Afuera Island west of Lima, and Macabí and Lobera islands along the edge of the continental platform. These data were complemented with the studies of some cutting samples obtained in recent exploration wells in northern Perú. The results of the present work show two large crustal domains in the Peruvian offshore forearc. A northern domain contains late Paleozoic igneous rocks that appear to be the southern offshore continuation of the Amotape-Tahuin block, which is interpreted as the southernmost remnant of the Laurentia Alleghenian orogen. The central offshore domain, known as the Paracas High, corresponds to the outer shelf high of previous studies. It contains orthogneisses of Grenville-age, probably recrystallized during an Ordovician magmatic episode. The new results show that the central offshore of Perú is an extension of the Grenville-age basement affected by Famatinian, early Paleozoic magmatism, well exposed in the southern domain in the Arequipa Massif along the coast of southern Perú.

  18. How Pecten Brazil drilled the Amazon basin

    SciTech Connect

    Bleakley, W.B.

    1983-09-01

    Pecten Brazil overcame numerous obstacles to drill two exploratory wells in the Amazon Basin last year. These included: The threat of low water in normally navigable rivers. Dense jungle growth at both locations. Lack of suitable roads for heavy hauling. Inconvenient distances from supply points. An unusual basalt formation responsible for unique drilling problems. Hundreds of helicopter lifts to move drilling rigs, supplies, and personnel. Pecten contracted with Petrobras, the Brazilian national oil company, to evaluate three blocks in the Amazon jungle, each about 68 miles (110 km) on a side, through seismic study and ultimate drilling. Planning for the drilling phase got started on March 17, 1981 with December 1 targeted as spud date for the first well. Actual spud date was November 25, 5 days ahead of schedule, in spite of all obstacles. Pecten has a mid-Amazonas block now under seismic investigation for possible exploratory drilling. Logistics problems in this one provide new difficulties, as the area is extremely wet. Most work is carried on by boat. The company is also looking offshore Bahia, testing the possible extension of the Renconcavo basin. Two wells have already provided good shows of a high pour point oil, with flow rates from 400 to 1,000 b/d. Another area of interest to Pecten is offshore Rio Grande do Norte.

  19. Leveraging Somali Basin Magnetic Anomalies to Constrain Gondwana Breakup and Early Indian Ocean Formation

    NASA Astrophysics Data System (ADS)

    Davis, J. K.; Lawver, L. A.; Norton, I. O.; Gahagan, L.

    2015-12-01

    The Somali Basin, found between the Horn of Africa and Madagascar was formed during the rifting of East and West Gondwana. Understanding the evolution of the basin has historically been hindered by enigmatic seafloor fabric and an apparent paucity of magnetic anomaly data. Recent iterations of satellite gravity data have revealed nearly complete fracture zones as well as a distinct extinct spreading ridge within the basin. Through a thorough compilation of available Somali Basin shiptrack profiles, we have been able to successfully model and interpret magnetic anomalies with exceptional detail. This complication is unrivaled in completeness and provides unprecedented insight into basin formation. Using this high quality data, we have interpreted magnetic anomalies M0r (120.8 Ma) to M24Bn (152.43 Ma) about the extinct ridge. The interpreted Somali Basin spreading rate and spreading direction, through anomaly M15n (135.76 Ma), are similar to those observed in the neighboring coeval Mozambique Basin. This similarity suggests that East Gondwana separated from West Gondwana as a cohesive unit, and that the internal rifting of East Gondwana began later around 135 Ma. Our magnetic anomaly interpretations have been combined with additional magnetic interpretations from around the Indian Ocean to build a regionally consistent plate model of Gondwana breakup and early Indian Ocean formation. This plate model will be crucial for future efforts unraveling a precise history of East Gondwana fragmentation and constraining the formation of the Enderby Basin offshore East Antarctica and Bay of Bengal offshore East India.

  20. Mapping Seabird Sensitivity to Offshore Wind Farms

    PubMed Central

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

    2014-01-01

    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

  1. Mapping seabird sensitivity to offshore wind farms.

    PubMed

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

    2014-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2002-12-01

    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 local water agencies to (1) understand and model the process of salt-water intrusion in this siliciclastic, structurally complex basin, and (2) identify potential pathways for the salt-water intrusion. We collected over 2000 trackline-km of single- and multi-channel intermediate- and high-resolution seismic-reflection profiles (60 to 5000 Hz) from the Los Angeles/Long Beach Harbor complex and the adjacent San Pedro shelf to develop a 3-dimensional stratigraphic model of the coastal aquifer system. These data define stratal geometries, paleo-channels, and fault traces in the offshore that are potential pathways of salt-water intrusion. The offshore seismic-reflection profiles correlate with onshore geophysical and borehole data collected from four nearby drill sites that were cored continuously to depths ranging to 400 meters. These core holes provide detailed 1-dimensional reference sections that furnish stratigraphic, age, and facies control for the seismic-reflection profiles. The coastal aquifer system is described using sequence stratigraphic concepts as units deposited during eustatic sea level fluctuations during the Pleistocene to Recent. Seismic-reflection profiles identify sequence boundaries, and hence aquifer and aquitard units, by the truncation and onlap of reflectors. If and where the sequences crop out on the sea floor provides a potential pathway for intrusion. The youngest unit, the Gaspur aquifer, is intruded with salt water and consists of at least two flat-lying sequences, each marked by basal gravelly sands deposited by the ancestral Los Angeles

  3. Holocene morphologic changes offshore the Quarteira region, Algarve, south Portugal

    NASA Astrophysics Data System (ADS)

    Noiva, João.; Duarte, Henrique; Terrinha, Pedro; Gonçalves, Daniela

    2010-05-01

    A 160 km long SPARKER single channel seismic reflection survey was acquired in November 2008 on the shallow continental shelf of south Portugal to investigate the recent tectonics of the S.Marcos - Quarteira Fault (SMQF) and of the Carcavai Fault. The NW-SE trending S.Marcos - Quarteira Fault (SMQF) can be traced on the onshore-offshore region of south Portugal for an extension of 160 km. It is a Variscan (Hercynian) orogenic thrust that was inverted as an extensional fault during the Mesozoic rifting in south Portugal, during which it played a major role in the segmentation of the Algarve Basin. The SMQF was re-inverted as a transpressive fault during the Paleogene-Miocene compression and folding and thrusting of Pleistocene terrigenous strata attest for its present day tectonic activity. The Carcavai fault trends NE-SW, intersects the SMQF. The Carcavai fault also played the role of rift fault during the Mesozoic and was inverted as a thrust during the Cenozoic compression. The mapping of both SMQ and Carcavai Faults offshore south Portugal attests for a complex interaction between the two in what concerns the Holocene and tectonics and paleogeography. The Carcavai Fault accommodates most of the Pliocene-Quaternary compression on its hanging-wall, whilst the SMQF takes up the deformation on the foot-wall of the Carcavai Fault. In what refers the early Holocene paleogeography, the interpretation of the seismic profiles shows the existence of two sedimentary bodies of possible Holocene age separated by a peninsula that consists of Pliocene-Pleistocene prograding clastics that make up the present day coastal cliff. This peninsula is parallel to the present day coastline, which is also parallel to the SMQF. The two bodies have different seismic facies. The offshore Holocene displays fairly continuous reflections, whilst the internal Holocene is made up of more discontinuous reflections. The isobaths map of the base of the external Holocene unit shows a smooth gently

  4. Offshore fault system in the Al Hoceima region from new high-resolution bathymetric and seismic reflection data

    NASA Astrophysics Data System (ADS)

    Lafosse, Manfred; d'Acremont, Elia; Rabaute, Alain; Mercier de l'Epinay, Bernard; Gorini, Christian; André Gutscher, Marc; Poort, Jeffrey; Ammar, Abdellah; Tahayt, Abdelilah; Leroy, Pascal; Smit, Jeroen; Do Couto, Damien; Cancouët, Romain; Prunier, Christophe; Ercilla, Gemma

    2014-05-01

    The Al-Hoceima Region (Morocco) is the one of the most active seismic area of the western Mediterranean Sea. Detailed surveys in a shallow water environment are required to identify the connecting onshore-offshore active structures and to propose a tectonic framework. We use combined high-resolution seismic reflection and swath-bathymetry data from the Marlboro-2 cruise, which took place in 2012 off the coast of Al Hoceima, to detail the fault system through the Nekor basin, between the Trougout Fault and the Boussekour Agdal fault. The Boussekour-Agdal fault is a N026 oriented fault, dipping east and affecting the plio-quaternary sequence offshore and the internal units of the oriental Rif onshore. The fault trace shows a vertical offset of 6.5 m on the high-resolution swath bathymetry close to the shoreline, while the northern prolongation of the fault is buried. The Bokkoya fault (Calvert et al. 1997) is a N029 oriented fault dipping east. The vertical offset at the seafloor is 13m. This fault affects sedimentary structures above a paleo-terrace at -105mbsl, probably related to the last sea-level fall. The onshore-offshore N-S oriented Trougout fault corresponds to the eastern boundary between the plio-quaternary Nekor basin and the volcano-clastic deposits of Ras Tarf. This fault produces a vertical offset of 2.3m at the sea-floor. These three major fault zones limit two basins: the Nekor basin between the Bokkoya and the Trougout faults, and a depression between the Boussekour-Agdal and the Bokkoya Faults. The quaternary deposits are syn-tectonic. In the Nekor basin secondary normal faults are oriented N150, shift the sea-floor and affect the Messinian unconformity. Successive positions of a paleo-canyon (seen in the seismic lines) show a migration of the subsidence from east to west inside the Nekor basin. Faults affecting the Messinian unconformity control this subsidence. Between the Boussekour-Agdal and the Bokkoya faults, the thickness and the geometry of

  5. Evolution and hydrocarbon prospectivity of the Douala Basin, Cameroon

    SciTech Connect

    Batupe, M.; Tampu, S.; Aboma, R.S.

    1995-08-01

    The Douala Basin is a stable Atlantic-type, predominantly offshore basin and forms the northern terminal of a series of divergent passive margin basins located on the Southwest coast of Africa that resulted from the rifting of Africa from South America. An integration of new studies including detailed well, biostratigraphic, sedimentological, geochemical and seismic data has confirmed that the tectonostratigraphic evolution in the basin can be broadly divided into three developmental phases: the Syn-rift, Transitional and Drift phases. This basis has been explored intermittently for hydrocarbon for the past 40 years with two important gas fields discovered and no commercial oil found as yet. This early gas discovery and a corresponding lack of any significant oil discovery, led early operators to term this basin as essentially a gas province. However, recent geochemical analyses of various oil-seeps and oil samples from various localities in the basin, using state-of-the-art techniques have demonstrated that this basin is a potential oil prone basin. The results show that two models of oil sourcing are possible: a Lower Cretaceous lacustrine saline source, similar to the presalt basins of Gabon or a marine Upper Cretaceous to lower Tertiary source, similar to the neighbouring Rio del Rey/Niger Delta Complex. Additionally, seismic reflection data also demonstrate a variety of reservoir horizons, including submarine fans, channel-like features and buried paleohighs, all interbedded within regionally extensive, uniformity bounded mudstone units. Hence, it is now quite evident that within this basin, there exist a vast potential for a wide variety of stratigraphic, structural and combined traps. These features, which are considered to have significantly enhanced the prospectivity of this basin, will be discussed in this paper.

  6. Geological structure of the offshore Sumatra forearc region estimated from high-resolution MCS reflection survey

    NASA Astrophysics Data System (ADS)

    Misawa, Ayanori; Hirata, Kenji; Seeber, Leonard; Arai, Kohsaku; Nakamura, Yasuyuki; Rahardiawan, Riza; Udrekh; Fujiwara, Toshiya; Kinoshita, Masataka; Baba, Hisatoshi; Kameo, Katsura; Adachi, Keita; Sarukawa, Hiroshi; Tokuyama, Hidekazu; Permana, Haryadi; Djajadihardja, Yusuf S.; Ashi, Juichiro

    2014-01-01

    To investigate detailed fault distributions and shallow geological structure offshore northwestern Sumatra, we obtained high-resolution Multi-Channel Seismic (MCS) reflection data around the Sunda Trench, trench slope, and forearc high regions offshore northwestern Sumatra. In general, trench-parallel anticlinal ridges are distributed from trench slope region to forearc high region. Two kinds of different vergence systems are characterized in the Sumatra forearc region; landward vergence is dominant in the lower trench slope region, and seaward vergence is dominant in the forearc high region. Moreover, piggyback or slope basins are recognized between anticlinal ridges. Deformation in the uppermost part of these basins, that is referred to ‘recent’ deformation in this paper, can be identified not only along major thrusts but also between major thrusts and the lower trench slope, suggesting these are related to recently active faulting. Several but the largest number of such deformation are distributed along a major thrust located in the middle of the forearc high region, whereas few are done along other major thrusts.

  7. Using altimetry and seafloor pressure data to estimate vertical deformation offshore: Vanuatu case study

    NASA Astrophysics Data System (ADS)

    Ballu, V.; Bonnefond, P.; Calmant, S.; Bouin, M.-N.; Pelletier, B.; Laurain, O.; Crawford, W. C.; Baillard, C.; de Viron, O.

    2013-04-01

    Measuring ground deformation underwater is essential for understanding Earth processes at many scales. One important example is subduction zones, which can generate devastating earthquakes and tsunamis, and where the most important deformation signal related to plate locking is usually offshore. We present an improved method for making offshore vertical deformation measurements, that involve combining tide gauge and altimetry data. We present data from two offshore sites located on either side of the plate interface at the New Hebrides subduction zone, where the Australian plate subducts beneath the North Fiji basin. These two sites have been equipped with pressure gauges since 1999, to extend an on-land GPS network across the plate interface. The pressure series measured at both sites show that Wusi Bank, located on the over-riding plate, subsides by 11 ± 4 mm/yr with respect to Sabine Bank, which is located on the down-going plate. By combining water depths derived from the on-bottom pressure data with sea surface heights derived from altimetry data, we determine variations of seafloor heights in a global reference frame. Using altimetry data from TOPEX/Poseidon, Jason-1, Jason-2 and Envisat missions, we find that the vertical motion at Sabine Bank is close to zero and that Wusi Bank subsides by at least 3 mm/yr and probably at most 11 mm/yr.This paper represents the first combination of altimetry and pressure data to derive absolute vertical motions offshore. The deformation results are obtained in a global reference frame, allowing them to be integrated with on-land GNSS data.

  8. Calibration and validation of a spar-type floating offshore wind turbine model using the FAST dynamic simulation tool

    SciTech Connect

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

    2014-01-01

    In this study, high-quality computer simulations are required when designing floating wind turbines because of the complex dynamic responses that are inherent with a high number of degrees of freedom and variable metocean conditions. 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. Wave basin tests with the spar attached to a scale model of the NREL 5-megawatt reference wind turbine were performed at the Maritime Research Institute Netherlands under the DeepCwind project. This project included free-decay tests, tests with steady or turbulent wind and still water (both periodic and irregular waves with no wind), and combined wind/wave tests. The resulting data from the 1/50th model was scaled using Froude scaling to full size and used to calibrate and validate a full-size simulated model in FAST. Results of the model calibration and validation include successes, subtleties, and limitations of both wave basin testing and FAST modeling capabilities.

  9. Calibration and validation of a spar-type floating offshore wind turbine model using the FAST dynamic simulation tool

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    High-quality computer simulations are required when designing floating wind turbines because of the complex dynamic responses that are inherent with a high number of degrees of freedom and variable metocean conditions. 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. Wave basin tests with the spar attached to a scale model of the NREL 5-megawatt reference wind turbine were performed at the Maritime Research Institute Netherlands under the DeepCwind project. This project included free-decay tests, tests with steady or turbulent wind and still water (both periodic and irregular waves with no wind), and combined wind/wave tests. The resulting data from the 1/50th model was scaled using Froude scaling to full size and used to calibrate and validate a full-size simulated model in FAST. Results of the model calibration and validation include successes, subtleties, and limitations of both wave basin testing and FAST modeling capabilities.

  10. Calibration and validation of a spar-type floating offshore wind turbine model using the FAST dynamic simulation tool

    DOE PAGESBeta

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

    2014-01-01

    In this study, high-quality computer simulations are required when designing floating wind turbines because of the complex dynamic responses that are inherent with a high number of degrees of freedom and variable metocean conditions. 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 inmore » 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. Wave basin tests with the spar attached to a scale model of the NREL 5-megawatt reference wind turbine were performed at the Maritime Research Institute Netherlands under the DeepCwind project. This project included free-decay tests, tests with steady or turbulent wind and still water (both periodic and irregular waves with no wind), and combined wind/wave tests. The resulting data from the 1/50th model was scaled using Froude scaling to full size and used to calibrate and validate a full-size simulated model in FAST. Results of the model calibration and validation include successes, subtleties, and limitations of both wave basin testing and FAST modeling capabilities.« less

  11. Petroleum Systems in the Austral Basin

    SciTech Connect

    Robbiano, J.; Arbe, H.

    1996-08-01

    The aggressive exploration activities pursued over the past five years, both onshore and offshore, have contributed to increase our knowledge about how the Petroleum Systems functioned within the basin. Three main Petroleum Systems were identified, and referred to as Jurassic, Lower Cretaceous and Aptian-Tertiary Petroleum Systems. The Jurassic P.S. is restricted to the volcanic, volcaniclastic and clastic sequences (known as Tobifera Series) related to the opening of the South Atlantic Ocean. Lacustrine to marine black shales give good source rock, locally developed; oil and gas, poorly developed, was trapped in fluvial to littoral sandstones, related to the same sedimentary cycle. The Lower Cretaceous P.S. represents the main petroleum system of the Austral Basin, and it is related to the main oil and gas accumulations today known within the basin. The lateral relation between the marine source rocks (Palermo Aike, Inoceramus Inferior, Pampa Rincon Formations) and the continental to littoral Springhill Formation in a transgressive signature indicates the extent of the migration from the oil kitchen, in the present deep location of the basin, to the shallow eastern flank of the Austral Basin. The cumulative production and reserves of this efficient petroleum system are more than 400 MM of petroleum and gas equivalent. The Aptian-Tertiary P.S. is related to the Margas Verdes source rock that has fed younger reservoirs which have developed since the Upper Cretaceous (?)-Palaeocene and could also feed Upper Oligocene sandstones, associated with low-stand system tracts. Commercial accumulations were tested in Campo Boleadoras and Maria Ines fields, towards the deepest zones of the Austral Basin. This petroleum system will figure prominently in exploration activities over the coming years, specifically in those areas where the main petroleum system is not laterally efficient.

  12. Plio-Quaternary tectonic evolution off Al Hoceima, Moroccan Margin of the Alboran Basin.

    NASA Astrophysics Data System (ADS)

    Lafosse, Manfred; d'Acremont, Elia; Rabaute, Alain; Mercier de Lépinay, Bernard; Gorini, Christian; Ammar, Abdellah; Tahayt, Abdelilah

    2015-04-01

    We use data from a compilation of industrial and academic 2D surveys and recent data from MARLBORO-1 (2011), MARLBORO-2 (2012), and SARAS (2012) surveys, which provide high resolution bathymetry and 2D seismic reflexion data. We focus on the key area located south of the Alboran Ridge and the Tofiño Bank, and encompassing the Nekor and Boudinar onshore-offshore basins on the Moroccan side of the Alboran Sea. The Nekor basin is a present pull-apart basin in relay between inherited N050° sinistral strike-slip faults. We consider that these faults define the Principal Displacement Zones (PDZ). The northern PDZ marks the position of the crustal Bokkoya fault, which is connected to the Al-Idrisi Fault Zone en relais with the Adra and Carboneras Fault Zones. On the seabed, right-stepping non-coalescent faults characterize the sinistral kinematics of the northern PDZ and give a general N050° azimuth for the crustal discontinuity. The southern PDZ corresponds to the Nekor fault Zone, a Miocene sinistral strike-slip fault acting as the structural limit of the External Rif. On its eastern edge, the Nekor basin is bounded by the N-S onshore-offshore Trougout fault, connecting the northern and the southern PDZ. The western boundary of the Nekor basin is marked by the Rouadi and El-Hammam Quaternary active N-S normal faults. In the offshore Nekor basin, recent N155° conjugated normal faults affect the seabed. Further east, the Boudinar basin is a Plio-Quaternary uplifted Neogene basin. The northeastern segment of the Nekor fault bounds this basin to the south but is inactive in the Quaternary. Normal east-dipping N150° faults are visible offshore in the continuity of the Boudinar fault. From our perspective, the orientation of major tectonic structures (Bokkoya, Nekor and Carboneras faults and the Alboran ridge) under the present compressive regime due to the Europe/Africa convergence is not compatible with a strike-slip motion. The orientation of the most recent Plio

  13. Tectonic controls on the hydrocarbon habitats of the Barito, Kutei, and Tarakan Basins, Eastern Kalimantan, Indonesia: major dissimilarities in adjoining basins

    NASA Astrophysics Data System (ADS)

    Satyana, Awang Harun; Nugroho, Djoko; Surantoko, Imanhardjo

    1999-04-01

    The Barito, Kutei, and Tarakan Basins are located in the eastern half of Kalimantan (Borneo) Island, Indonesia. The basins are distinguished by their different tectonic styles during Tertiary and Pleistocene times. In the Barito Basin, the deformation is a consequence of two distinct, separate, regimes. Firstly, an initial transtensional regime during which sinistral shear resulted in the formation of a series of wrench-related rifts, and secondly, a subsequent transpressional regime involving convergent uplift, reactivating old structures and resulting in wrenching, reverse faulting and folding within the basin. Presently, NNE-SSW and E-W trending structures are concentrated in the northeastern and northern parts of the basin, respectively. In the northeastern part, the structures become increasingly imbricated towards the Meratus Mountains and involve the basement. The western and southern parts of the Barito Basin are only weakly deformed. In the Kutei Basin, the present day dominant structural trend is a series of tightly folded, NNE-SSW trending anticlines and synclines forming the Samarinda Anticlinorium which is dominant in the eastern part of the basin. Deformation is less intense offshore. Middle Miocene to Recent structural growth is suggested by depositional thinning over the structures. The western basin area is uplifted, large structures are evident in several places. The origin of the Kutei structures is still in question and proposed mechanisms include vertical diapirism, gravitational gliding, inversion through regional wrenching, detachment folds over inverted structures, and inverted delta growth-fault system. In the Tarakan Basin, the present structural grain is typified by NNE-SSW normal faults which are mostly developed in the marginal and offshore areas. These structures formed on older NW-SE trending folds and are normal to the direction of the basin sedimentary thickening suggesting that they developed contemporaneously with deposition, as

  14. Geofluid Dynamics of Faulted Sedimentary Basins

    NASA Astrophysics Data System (ADS)

    Garven, G.; Jung, B.; Boles, J. R.

    2014-12-01

    Faults are known to affect basin-scale groundwater flow, and exert a profound control on petroleum migration/accumulation, the PVT-history of hydrothermal fluids, and the natural (submarine) seepage from offshore reservoirs. For example, in the Santa Barbara basin, measured gas flow data from a natural submarine seep area in the Santa Barbara Channel helps constrain fault permeability k ~ 30 millidarcys for the large-scale upward migration of methane-bearing formation fluids along one of the major fault zones. At another offshore site near Platform Holly, pressure-transducer time-series data from a 1.5 km deep exploration well in the South Ellwood Field demonstrate a strong ocean tidal component, due to vertical fault connectivity to the seafloor. Analytical solutions to the poroelastic flow equation can be used to extract both fault permeability and compressibility parameters, based on tidal-signal amplitude attenuation and phase shift at depth. These data have proven useful in constraining coupled hydrogeologic 2-D models for reactive flow and geomechanical deformation. In a similar vein, our studies of faults in the Los Angeles basin, suggest an important role for the natural retention of fluids along the Newport-Inglewood fault zone. Based on the estimates of fault permeability derived above, we have also constructed new two-dimensional numerical simulations to characterize large-scale multiphase flow in complex heterogeneous and anisotropic geologic profiles, such as the Los Angeles basin. The numerical model was developed in our lab at Tufts from scratch, and based on an IMPES-type algorithm for a finite element/volume mesh. This numerical approach allowed us model large differentials in fluid saturation and relative permeability, caused by complex geological heterogeneities associated with sedimentation and faulting. Our two-phase flow models also replicated the formation-scale patterns of petroleum accumulation associated with the basin margin, where deep

  15. Morphotectonics of the Southern Puerto Rico Offshore Margin

    NASA Astrophysics Data System (ADS)

    Granja Bruna, J.; Carbó-Gorosabel, A.; Llanes Estrada, P.; Ten Brink, U. S.; Munoz Martin, A.; Fuertes Ortega, R.; Druet, M.; Gómez, M.; Martin Davila, J. M.; Pazos, A.; Catalan, M.

    2012-12-01

    The southern insular slope of Puerto Rico is characterized by active tectonics, sedimentary and slope failure processes related to the southward thrusting of the island arc over the Caribbean plate's interior. The east-west trending Muertos fold-and-thrust belt and the Investigator fault zone are the main structural and morphological features along the insular slope. It was suggested that these tectonic features accommodate a highly oblique motion between the Caribbean plate's interior and the North American plate. New systematic multibeam bathymetry data and seismic reflection profiles have allowed us to improve the knowledge of the complex morphologic and structural fabric of this zone of active deformation. We divided the region into morphotectonic slope provinces on the basis of morphological, structural and sedimentological criteria. The lower slope province is occupied by the east-west trending Muertos fold-and-thrust belt. Seismic data image pelagic, hemipelagic and turbiditic sediments of the Venezuelan basin and Muertos Trough basin being partially offscraped and accreted forming a sequence of numerous imbricate thrust slices verging southwards. The surface expression of the imbricate structure is a highly steeped slope characterized by an alternation of narrow troughs and elongate anticline ridges oriented sub-parallel to the deformation front. The upper slope province is occupied by the Investigator fault zone, a broad zone of deformation composed of two straight strands that form narrow E-W trending valleys in the insular slope. Submarine canyons carve through the narrow E-W trending valleys or terminate in them but show no evidence for lateral offsets, indicating an absence of recent strike-slip motion. The seafloor expression of the Investigator fault zone suggests a sub-vertical fault plane accommodating a small amount of N-S extension. This fault zone terminates eastward in Whiting basin and disappears westwards beneath the thick slope deposits on a

  16. Potential cretaceous play in the Rharb basin of northern Morocco

    SciTech Connect

    Jobidon, G.P. )

    1993-09-01

    The autochthonous Cretaceous in the Rharb basin of northern Morocco is located underneath a cover of neogene sediments and of the Prerif nappe olistostrome, which was emplaced during the Tortonian 7 m.y. The presence of infranappe Cretaceous sediments is documented in a few onshore wells in the Rharb basin and in the adjacent Prerif Rides area, as well as in the Rif Mountains. Their presence in the deeper portion of the Rharb basin is difficult to detail because of poor seismic resolution data beneath dispersive prerif nappe. A recent study of offshore seismic data acquired by PCIAC in 1987 indicates that the infranappe interval can be more than 1500 m thick in some of the offshore Kenitra area. These sediments have seismic signatures that would correspond to Middle Cretaceous transgressions, culminating with a Turonian highstand. Their deposition systems were located on the northern and western flanks of the Meseta and were followed by a hiatus lasting until the Miocene. Regional studies of gravity and magnetic data provide and additional understanding of the Rif province, its evolution, and the possible presence of autochthonous Cretaceous sediments below the prerif nappe cover. The infranappe of Rharb basin has a good potential to develop into a major hydrocarbon play with the presence of middle Cretaceous reservoir rocks, Turonian-Cenomanian black shale source rocks, as well as the timely combination of trap formation, source rock maturation, and hydrocarbon migration.

  17. Locating Microseism Sources in Offshore Southern California

    NASA Astrophysics Data System (ADS)

    Tian, X.; Clayton, R. W.

    2007-12-01

    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.

  18. Offshore hydraulics: tough, reliable, and failsafe

    SciTech Connect

    Hoock, C.J.

    1983-08-01

    The Offshore Comet is a modern offshore drilling rig with a hydraulic-cylinder-actuated jacking (raising and lowering) system. Hydraulic-cylinder jacking provides a safe and efficient method for placing the rig at the desired height above the water and insuring that it can withstand the expected heavy loads imposed by machinery, supplies, and the ocean environment. The drilling rig consists of a steel-hulled barge that is floated to the site and then supported during drilling operations by four steel triangular-cross-section lattice legs. The legs are planted firmly on the ocean bottom by a procedure called preloading. Each leg with its integral footing weighs 657 tons. The barge with its deck load can weigh up to 9200 tons.

  19. Active Venting System Offshore Northern Norway

    NASA Astrophysics Data System (ADS)

    Chand, Shyam; Rise, Leif; Bellec, Valérie; Dolan, Margaret; Bøe, Reidulv; Thorsnes, Terje; Buhl-Mortensen, Pål; Buhl-Mortensen, Lene

    2008-07-01

    A combined sediment-sampling, high-resolution seismic, multiple echo sounder, and video survey was conducted offshore Vesterålen, northern Norway, in October 2007 as part of the ongoing Marine Area Database for Norwegian Coast and Oceanic Regions (MAREANO) program. MAREANO is a multidisciplinary seabed mapping program conducting physical, biological, and environmental mapping in the Lofoten/southern Barents Sea area. Data and analysis arising from this program will provide the basis for ecosystem-based management of Norway's coastal and offshore regions. The survey used multicorer, box corer, and grab samplers; a TOPAS parametric subbottom profiler; 18-, 38-, 70-, 120-, 200-, and 400-kilohertz echo sounders; and a CAMPOD camera system with two video cameras and lights mounted on an aluminum frame.

  20. Offshore desulfurization unit permits gas lift operations

    SciTech Connect

    Cabes, A.; Elgue, J.; Tournier-Lasserve, J. )

    1992-01-13

    This paper reports on the installation of a desulfurization unit for the Tchibouela oil field, offshore Congo, which allowed produced low-pressure associated gas containing CO{sub 2} to be kept for gas lift operations while, for safety reasons, the large volume of H{sub 2}S at low pressure was removed prior to compression. Since October 1989, the world's first offshore amine sweetening unit has worked satisfactorily and continues to prove that it is an attractive production alternative. For desulfurization, a selective methyldiethanolamine (MDEA) process, developed by Elf Aquitaine, was chosen because it was the only process that met the required specifications at a low pressure of 3.5 bar (51 psi).

  1. The International Standards Organisation offshore structures standard

    SciTech Connect

    Snell, R.O.

    1994-12-31

    The International Standards Organisation has initiated a program to develop a suite of ISO Codes and Standards for the Oil Industry. The Offshore Structures Standard is one of seven topics being addressed. The scope of the standard will encompass fixed steel and concrete structures, floating structures, Arctic structures and the site specific assessment of mobile drilling and accommodation units. The standard will use as base documents the existing recommended practices and standards most frequently used for each type of structure, and will develop them to incorporate best published and recognized practice and knowledge where it provides a significant improvement on the base document. Work on the Code has commenced under the direction of an internationally constituted sub-committee comprising representatives from most of the countries with a substantial offshore oil and gas industry. This paper outlines the background to the code and the format, content and work program.

  2. Offshore production riser with flexible connector

    SciTech Connect

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

    1981-06-16

    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.

  3. Improved thermoplastic materials for offshore flexible pipes

    SciTech Connect

    Dawans, F.; Jarrin, J.; Hardy, J.

    1988-08-01

    Long-term aging tests representative of field operating conditions have been conducted on various thermoplastic materials proposed for the inner tube of flexible pipes for offshore drilling and production applications. In particular, experimental data are provided about the changes of the mechanical properties of selected thermoplastic materials owing to optimized formulation when the pipes are exposed over time to crude oil in the presence of gas and water.

  4. Protective riser-conductor for offshore structures

    SciTech Connect

    Rutherford, D. A.; Albers, G. P.

    1985-07-09

    A protective sleeve for fitting about the periphery of the leg of an offshore structure. The sleeve comprises means for carrying and enclosing a plurality of conductors. It further includes one or more inner rings; an outer jacket is fixedly spaced from the rings to define longitudinal passages within which the respective conductors are fixedly positioned. The sleeve is capable of deflecting packed ice and floating objects which represent possible sources of damage to the structure or to conductors.

  5. Arctic and offshore research: Technology status report

    SciTech Connect

    Not Available

    1988-01-01

    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.

  6. Designing Australia's North West Shelf offshore pipeline

    SciTech Connect

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

    1984-05-07

    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.

  7. Caisson shield for arctic offshore production platform

    SciTech Connect

    Clinton, J. D.; Reusswig, G. H.

    1985-03-12

    A caisson shield for the protection of an offshore production platform and, more particularly, a caisson shield for use in an arctic environment for the protection of the offshore structure in iceberg-infested waters which is capable of absorbing the destructive forces of an impact produced by a large iceberg. The caisson shield consists of an essentially annular concrete structure encircling at least the submerged support section of the offshore production platform including vertically upstanding concentrically spaced, annular side walls, a horizontal slab base resting on the marine bottom on which the side walls are supported, and a slab top supported on the side walls, and including annularly spaced internal radial partition walls whereby the entire overall caisson shield structure provides a generally toroidal configuration incorporating a plurality of closed compartments. In one embodiment of the invention, located along the outer annular wall is a plurality of arcuate wall sections forming a series of arches and enclosed compartments between each arcuate wall section and the outer annular wall, which impart a ''scallop-like'' configuration to the outer circumference of the caisson shield. The ''scallop-like'' outer walls are capable of resisting and absorbing extremely high ice loads by being adapted to progressively crush the leading edge of an impacting iceberg and to thereby minimize the crush of the iceberg against the caisson shield before coming to rest against the shield.

  8. California State Waters Map Series: offshore of Carpinteria, California

    USGS Publications Warehouse

    Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Kvitek, Rikk G.; Greene, H. Gary; Endris, Charles A.; Seitz, Gordon G.; Sliter, Ray W.; Erdey, Mercedes D.; Wong, Florence L.; Gutierrez, Carlos I.; Krigsman, Lisa M.; Draut, Amy E.; Hart, Patrick E.

    2013-01-01

    and a few small residential clusters. Rincon Point is a well-known world-class surf break, and Rincon Island, constructed for oil and gas production, lies offshore of Punta Gorda. The steep bluffs backing the coastal strip are geologically unstable, and coastal erosion problems are ongoing in the map area; most notably, landslides in 2005 struck the small coastal community of La Conchita, engulfing houses and killing ten people. The Offshore of Carpinteria map area lies in the central part of the Santa Barbara littoral cell, whose littoral drift is to the east-southeast. Drift rates have been estimated to be about 400,000 tons/yr at Santa Barbara Harbor (about 15 km west of Carpinteria). At the east end of the littoral cell, eastward-moving sediment is trapped by Hueneme and Mugu Canyons and then transported to the deep-water Santa Monica Basin. Sediment supply to the western and central part of the littoral cell is largely from relatively small transverse coastal watersheds, which have an estimated cumulative annual sediment flux of 640,000 tons/yr. The much larger Ventura and Santa Clara Rivers, the mouths of which are about 25 to 30 km southeast of Carpinteria, yield an estimated 3.4 million tons of sediment annually, the coarser sediment load generally moving southeast, down the coast, and the finer sediment load moving both upcoast and offshore. The offshore part of the map area consists of a relatively flat and shallow continental shelf, which dips so gently (about 0.4° to 0.5°) that water depths at the 3-nautical-mile limit of California’s State Waters are 40 to 45 m. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north and northwest by Point Conception and from the south and southwest by offshore islands and banks. Fair-weather wave base is typically shallower than 20-m water depth, but winter storms are capable of resuspending fine-grained sediments in 30 m of water, and so shelf sediments in the map

  9. Evaluation of modeling as a tool to determine the potential impacts related to drilling wastes in the Brazilian offshore.

    PubMed

    Pivel, María Alejandra Gómez; Dal Sasso Freitas, Carla Maria

    2010-08-01

    Numerical models that predict the fate of drilling discharges at sea constitute a valuable tool for both the oil industry and regulatory agencies. In order to provide reliable estimates, models must be validated through the comparison of predictions with field or laboratory observations. In this paper, we used the Offshore Operators Committee Model to simulate the discharges from two wells drilled at Campos Basin, offshore SE Brazil, and compared the results with field observations obtained 3 months after drilling. The comparison showed that the model provided reasonable predictions, considering that data about currents were reconstructed and theoretical data were used to characterize the classes of solids. The model proved to be a valuable tool to determine the degree of potential impact associated to drilling activities. However, since the accuracy of the model is directly dependent on the quality of input data, different possible scenarios should be considered when used for forecast modeling. PMID:20532618

  10. Deformation of the Bellingham Basin in the Northern Cascadia Forearc as Inferred from Potential Field Data

    NASA Astrophysics Data System (ADS)

    Taylor, J.; Wolf, L. W.; Blakely, R. J.; Sherrod, B. L.; Brown, J.

    2013-12-01

    The Bellingham basin, spanning onshore and offshore regions of northwestern Washington state and southwestern British Columbia, is deforming under north-south shortening in the north Cascadia forearc. Accommodating the regional strain are Holocene-active faults within the basin that have been traced both offshore and onshore on the basis of gravity, aeromagnetic, and limited seismic data. In this study, we add 160 new gravity measurements to an existing database to better define the geometry of the Bellingham basin and its relation to recently discovered NW-trending faults. The new gravity data, spaced at ~ 1 km in the study area, were collected to address gaps in the irregular spatial distribution of existing data and extrapolate deformation recorded in coastal areas eastward into the basin. Regional-residual separation methods and derivative maps suggest that the Bellingham basin is segmented into three smaller basins. The southeast-trending Birch Bay fault extends 30 km into the basin, in agreement with previous work. The Sandy Point fault to the south of Birch Bay and the Drayton Harbor fault to the north appear as pronounced NW-SE trending lineations in magnetic data but are not as apparent as the Birch Bay fault in the new gravity data. The new data indicate that the northern margin of the Bellingham basin follows an arcuate path, southeastward from Birch Bay, then curving northeastward to connect with the Boulder Creek Fault. Two cross-sectional 2.5D models crossing the Bellingham basin show that the Birch Bay fault is steeply dipping and closely associated with a NW-SE trending anticlinal structure involving the underlying Chuckanut Formation and older rocks. An industry seismic line located ~2 km north of the Birch Bay fault shows an anticline involving Quaternary strata, consistent with the cross-sectional models. Results from the study suggest that the Bellingham basin contains evidence of Holocene-active faulting that, like other forearc basins to the

  11. Long-term trends in habitat use of offshore demersal fishes in western Lake Huron suggest large-scale ecosystem change

    USGS Publications Warehouse

    Riley, Stephen C.; Adams, Jean V.

    2010-01-01

    We estimated mean depths of capture for offshore demersal fish species, grouped into three habitat-based guilds (shallow benthic, pelagic, and deep benthic), using fall bottom trawl data (27–73 m) in the western main basin of Lake Huron from 1976 to 2007. The mean depth of capture of the shallow and deep benthic guilds initially exhibited a trend toward capture in shallower water, switched to a trend toward capture in deeper water in 1991, and changed back to a trend toward capture in shallower water in 2001–2002. Species in the pelagic guild showed a similar pattern, but the initial change point occurred in 1981 for this guild. Individual species in these guilds showed variable patterns of depth distribution, but a feature common to all guilds and all pelagic and deep benthic species was a change to a trend toward capturing fish in shallower water that occurred nearly simultaneously (1999–2002). These common trends suggest that large-scale factors are affecting the habitat use of offshore demersal fish species in Lake Huron. The depth distributions of the three guilds have converged in recent years, indicating that the locations of suitable habitat for offshore demersal fishes may be changing. Our results indicate that the benthic ecology of the western main basin of Lake Huron is undergoing profound changes across a large spatial scale that are affecting the habitat use of offshore demersal fishes. We suggest that these changes are related to recent invasions of exotic species.

  12. 10 CFR 150.7 - Persons in offshore waters not exempt.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Persons in offshore waters not exempt. 150.7 Section 150.7... AGREEMENT STATES AND IN OFFSHORE WATERS UNDER SECTION 274 Continued Commission Regulatory Authority in Offshore Waters § 150.7 Persons in offshore waters not exempt. Persons in offshore waters are not...

  13. Offshore exploration in Australia: Is it a good business? A five year look back

    SciTech Connect

    Samson, P.N.

    1996-12-31

    In the 5 years from 1991 to 1995 the exploration business in Australia has undergone significant changes. Most notable are the shift of exploration focus from Carnarvon Basin to the Timor Gap and the increased importance of gas prospectivity in the exploration portfolio. Diminishing acreage supply and increased maturity of existing acreage has meant that more and more subtle plays are being tested every year. The re-opening in 1991 of the Timor Gap (Zone of Cooperation) area for exploration saw a flurry of oil companies from around the world bidding fiercely for the 15 blocks on offer. The Elang oil and the Undan/Bayu gas condensate discovery have been the notable success stories. The Laminaria oil discovery in adjacent Australian waters was a direct result of the political settlement between Indonesia and Australia and the encouragement of the Elang discovery. The omnipresent gas strategy driven by domestic gas and Asian energy demand and advances in technology has pushed the oil companies to look for major gas resources in water depths of up to 1000m. While in the late 80`s gas prospect could not been given away, today they demand a very high premium. The renewed interest for gas has resulted in significant discoveries in the NWS and the opening of a new offshore gas province in the Otway Basin. Although not deliberate, part of the Timor Gap may also become a major gas province. Limited frontier offshore exploration took place during the period. Results of the drilling in the Duntroon and Browse Basins have provided hope for the more adventurous explorers. The discoveries made in the last 5 years have again shown that for those who are prepared to take on the challenge, Australia has the potential for considerable reward.

  14. Offshore exploration in Australia: Is it a good business A five year look back

    SciTech Connect

    Samson, P.N. )

    1996-01-01

    In the 5 years from 1991 to 1995 the exploration business in Australia has undergone significant changes. Most notable are the shift of exploration focus from Carnarvon Basin to the Timor Gap and the increased importance of gas prospectivity in the exploration portfolio. Diminishing acreage supply and increased maturity of existing acreage has meant that more and more subtle plays are being tested every year. The re-opening in 1991 of the Timor Gap (Zone of Cooperation) area for exploration saw a flurry of oil companies from around the world bidding fiercely for the 15 blocks on offer. The Elang oil and the Undan/Bayu gas condensate discovery have been the notable success stories. The Laminaria oil discovery in adjacent Australian waters was a direct result of the political settlement between Indonesia and Australia and the encouragement of the Elang discovery. The omnipresent gas strategy driven by domestic gas and Asian energy demand and advances in technology has pushed the oil companies to look for major gas resources in water depths of up to 1000m. While in the late 80's gas prospect could not been given away, today they demand a very high premium. The renewed interest for gas has resulted in significant discoveries in the NWS and the opening of a new offshore gas province in the Otway Basin. Although not deliberate, part of the Timor Gap may also become a major gas province. Limited frontier offshore exploration took place during the period. Results of the drilling in the Duntroon and Browse Basins have provided hope for the more adventurous explorers. The discoveries made in the last 5 years have again shown that for those who are prepared to take on the challenge, Australia has the potential for considerable reward.

  15. Proceedings - annual offshore technology conference, 13th, 1981

    SciTech Connect

    Anon

    1981-01-01

    The four volumes contain 183 papers presented at the meeting, all of which are indexed separately. Among the subjects covered are floating structure response, fatigue considerations in offshore systems, structural analysis and design, wave forces and hydroelastic response, offshore pipelines, ocean mining, tension leg platforms, oil terminals, geophysical data processing, seafloor surveying and mapping, subsea production systems, wind forces, towage of offshore structures, foundation performance, mooring and anchoring, and others.

  16. Three-dimensional æolian dynamics within a bowl blowout during offshore winds: Greenwich Dunes, Prince Edward Island, Canada

    NASA Astrophysics Data System (ADS)

    Hesp, Patrick A.; Walker, Ian J.

    2012-01-01

    This paper examines the æolian dynamics of a deep bowl blowout within the foredune of the Greenwich Dunes, on the northeastern shore or Prince Edward Island, Canada. Masts of cup anemometers and sonic anemometers were utilized to measure flow velocities and directions during a strong regional ESE (offshore) wind event. The flow across the blowout immediately separated at the upwind rim crest, and within the blowout was strongly reversed. High, negative vertical flows occurred down the downwind (but seaward) vertical scarp which projected into the separation envelope and topographically forced flow back into the blowout. A pronounced, accelerated jet flow existed near the surface across the blowout basin, and the flow exhibited a complex, anti-clockwise structure with the near-surface flow following the contours around the blowout basin and lower slopes. Significant æolian sediment transport occurred across the whole bowl basin and sediment was delivered by saltation and suspension out the blowout to the east. This study demonstrates that strong offshore winds produce pronounced topographically forced flow steering, separation, reversal, and more complex three-dimensional motions within a bowl blowout, and that such winds within a bowl blowout play a notable role in transporting sediment within and beyond deep topographic hollows in the foredune.

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

    SciTech Connect

    Jonkman, J.; Musial, W.

    2010-12-01

    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.

  18. The Alegre Lineament and its role over the tectonic evolution of the Campos Basin and adjacent continental margin, Southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Calegari, Salomão Silva; Neves, Mirna Aparecida; Guadagnin, Felipe; França, George Sand; Vincentelli, Maria Gabriela Castillo

    2016-08-01

    The structural framework and tectonic evolution of the sedimentary basins along the eastern margin of the South American continent are closely associated with the tectonic framework and crustal heterogeneities inherited from the Precambrian basement. However, the role of NW-SE and NNW-SSE structures observed at the outcropping basement in Southeastern Brazil and its impact over the development of those basins have not been closely investigated. In the continental region adjacent to the Campos Basin, we described a geological feature with NNW-SSE orientation, named in this paper as the Alegre Fracture Zone (AFZ), which is observed in the onshore basement and can be projected to the offshore basin. The main goal of this work was to study this structural lineament and its influence on the tectonic evolution of the central portion of the Campos Basin and adjacent mainland. The onshore area was investigated through remote sensing data joint with field observations, and the offshore area was studied through the interpretation of 2-D seismic data calibrated by geophysical well logs. We concluded that the AFZ occurs in both onshore and offshore as a brittle deformation zone formed by multiple sets of fractures that originated in the Cambrian and were reactivated mainly as normal faults during the rift phase and in the Cenozoic. In the Campos Basin, the AFZ delimitates the western side of the Corvina-Parati Low, composing a complex fault system with the NE-SW faults and the NW-SE transfer faults.

  19. Operational Impacts of Large Deployments of Offshore Wind (Poster)

    SciTech Connect

    Ibanez, E.; Heaney, M.

    2014-10-01

    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.

  20. Evolution history of the Heuksan Basin, a continental rift basin in the Yellow Sea

    NASA Astrophysics Data System (ADS)

    Yoon, S.; Kim, G.; Park, M.

    2011-12-01

    This study focuses on the establishment of evolutionary framework of the Heuksan Basin regions located on the southwestern part of the concession block III of the Korean offshore in the Yellow Sea. Three fault-bounded sub-basins (SB-1, SB-2, and SB-3) are recognized on the basis of topographic map of acoustic basement, which are generally in asymmetric half-graben geometry trending WNW-ESE. The axial lengths of the sub-basins are generally less than 80 km in axial length and 20 km in width. The acoustic basement occurs at around 0.6 to 0.8 s twt bsl in generally, locally much deeper at about 2.4 s twt bsl in the deepest part of the sub-basins, and it is correlated with the Upper Paleozoic to Lower Mesozoic sequence of thick micritic limestones overlying major clastic cycles with thin coals. In the sedimentary succession, two erosional surfaces (ES-1 and ES-2) are identified based on the interpretation of truncated geometries and lap-out patterns, which provide three stratigraphic units (SU-1, SU-2, and SU-3). During the Late Cretaceous to Oligocene the basin had opened by NE-SW extension or transtension. By this tectonic movement, WNW-ESE trending sub-basins with an array of listric normal faults were formed. Until the cessation of the opening, the wedge-shaped syn-rift unit (SU-1) infilled the depressions of the rift basins. In the Late Oligocene to Early Miocene time the extensional or transtensional tectonic movement of the Heuksan Basin region was aborted or partly inverted into compressional or transpressional regime. By this tectonic movement, acoustic basement and syn-rift unit (SU-1) might have uplifted, and have experienced a regional planation process. Topographic irregularities were removed by erosion and infilling process. SU-1 might have formed during this period in the localized topographic lows of the basins. Subaerial to shallow-marine planation process on the slightly folded and uplifted SU-1during subsequent tectonic inversion in the Early Miocene

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

    SciTech Connect

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

    2010-11-23

    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.

  2. Campano-Maastrichtian foraminifera from onshore sediments in the Rio del Rey Basin, Southwest Cameroon

    NASA Astrophysics Data System (ADS)

    Njoh, Oliver Anoh; Victor, Obiosio; Christopher, Agyingi

    2013-03-01

    Campanian-Maastrichtian marine sediments outcrop in five genetically linked sedimentary basins along the West African coast in the Gulf of Guinea, from the Douala Basin in Cameroon to the Anambra Basin in Nigeria. These sediments in the more centrally located Rio del Rey Basin have been the least studied. Therefore, the geologic history of this region has merely been speculative. The Rio del Rey Basin like the adjacent Niger Delta is producing hydrocarbon from the offshore Tertiary sedimentary interval in which all studies have been focused, neglecting the onshore Cretaceous sediments. Outcrops in the basin are rare, small and highly weathered. Samples from some of these sediments have yielded a few Planktonic and dominantly benthonic foraminiferal assemblages. The long-ranging heterohelix and hedbergellids characterized the planktics while the species Afrobolivina afra which is a well known diagnostic taxon for Campanian-Maastrichtian sediments in West African basins clearly dominate the benthic assemblage. Its occurrence in association with other Upper Cretaceous forms such as Bolivina explicata, Praebulimina exiqua, Gabonita lata, Ammobaculites coprolithiformis amongst others, formed the basis on which this age was assigned to the sediments sampled from the Rio del Rey Basin. Hence, this work has undoubtedly established the much needed link in this regional geologic history and correlates these sediments with the Logbaba and Nkporo Formations in the Douala Basin in Cameroon and the southeastern Nigerian Sedimentary Basins. Thus, these units were all deposited during this same geologic period and probably controlled by the same geologic event.

  3. Emplacement of magma in sedimentary basins

    NASA Astrophysics Data System (ADS)

    Malthe-Sorenssen, A.; Planke, S.

    2002-12-01

    Sheet-like intrusive complexes are commonly present in sedimentary basins on rifted volcanic margins. Such sill complexes have important impact on petroleum maturation, migration and trapping. We are currently completing an integrated seismic, field and theoretical study on the petroleum implications of sill intrusions. One aspect of this study has been to get new understanding of the magma emplacement processes based on integrated numerical modeling and geophysical/geological mapping activities. Extensive sill complexes have been identified and mapped in the NE Atlantic and Karoo basins based on seismic, borehole, remote sensing and field data. Early Tertiary intrusive complexes are present in the Voring and More basins offshore mid-Norway. Similar sill complexes are exposed onshore in Cretaceous to Permian age sedimentary sequences on the conjugate central-east Greenland margin. A voluminous Jurassic age intrusive complex is well exposed in the Permian to Jurassic Karoo basin as the erosionally strong dolerites form an impressive mountainous landscape in large parts of South Africa. The sheet intrusions are found at paleodepths of 0-6 km. Deep intrusions are generally long and smooth, whereas shallow intrusions are rough, transgressive and commonly saucer-shaped. Saucer-shaped intrusions are present in unstructured basin segments. The diameter of the saucers increases with depth. Structured basin segments are characterized by a variety of sill complex geometries. The intrusions generally mimic the basin structure. In nature, magma is emplaced in internally pressurized, planar cracks. The emplacement process is controlled by the local stress field and complex interactions of buoyancy forces, host rock resistance to fracture, elastic deformation of country rock, magma hydrostatic pressure and fluctuating magma pressure, magma viscosity and weight of overburden. We have developed a discrete element model to study the emplacement process. Results from the modeling

  4. Evolutionary sequences and hydrocarbon potential of Kenya sedimentary basins

    SciTech Connect

    Cregg, A.K. )

    1991-03-01

    Kenya basins have evolved primarily through extension related to episodic continental rifting. In eastern Kenya, thick accumulations of sediments formed within grabens during the prerift phase (Precambrian to Carboniferous) of the Gondwana breakup. Synrift sedimentation (Late Carboniferous to Middle Jurassic) occurred within a north-south rift system, which included the Mandera basin, South Anza basin, and Lamu embayment. During the Early Jurassic, a marine transgression invaded the margins of the eastern Kenya rift basins, resulting in the deposition of platform carbonates and shales. A Callovian-aged salt basin formed in the offshore regions of the Lamu embayment. Intermittent tectonic activity and eustatic sea-level changes controlled sedimentation, which produced marine shales, carbonates or evaporites, and fluvio-deltaic to lacustrine sandstones. From the Early Cretaceous to recent, continental sediments were deposited within the North Anza and Turkana basins. These fluvial-lacustrine sediments are similar to the Lower Cretaceous sequences that have produced oil in the Mesozoic Sudanese Abu Gabra rift. Although exploration activities began in the early 1950s, significant occurrences of potential reservoir, source, and seal lithologies as well as trapping configurations remain in many areas. Favorable structures and sequences of reservoir sandstones and carbonates overlain by potentially sealing lacustrine or marine shales, evaporites, or volcanics have been noted. Potential source beds are believed to be present within shales of the lacustrine or marine depositional environments.

  5. Integrated exploration study of Norwegian-Danish basin, northwestern Europe

    SciTech Connect

    Joergensen, N.B.; Haselton, T.M.

    1987-05-01

    The Norwegian-Danish basin (NDB) extends from offshore Norway southeast through Denmark. This study, initiated by the Danish Energy Agency to evaluate hydrocarbon potential, consists of geophysical structural and stratigraphic mapping combined with geologic source rock and reservoir analysis. Approximately 25 wells and 15,000 km of seismic data were included. Formation of the NDB resulted from uplift of the Variscan foldbelt followed by subsidence of the foreland, i.e., the NDB and the North German basin. The Ringkoebing-Fyn High, a positive feature probably established in the late Precambrian and persisting to present, separates the basins, thus constituting the southern boundary of the NDB. Northeast the basin is bounded by the Fennoscandian shield and to the west by the North Sea graben system. Following deposition of Rotliegendes eolian and fluviatile sandstones, a major Late Permian marine transgression deposited up to 2000 m of evaporites and carbonates. Early Triassic regression resulted in thick red-bed deposits. Halokinesis commencing in the Upper Triassic dominated subsequent structural development. Continued subsidence led to deposition of Early Jurassic shelf mudstones overlain by deltaic sandstones. Rising seas during Late Cretaceous allowed widespread deposition of oceanic pelagic chalk. Early Paleocene wrench movements produced inversion. Basinal downwarping during the Tertiary was accompanied by progradation from the northeast. The complex tectonic history provides numerous different structural styles and a variety of depositional environments. To date only obvious structural features have been tested. This integrated basin study demonstrates that a number of other hydrocarbon plays remain to be explored.

  6. Visayan Basin - the birthplace of Philippine petroleum exploration revisited

    SciTech Connect

    Rillera, F.G. ); Durkee, E.F. )

    1994-07-01

    Petroleum exploration in the Philippines has its roots in the Visayan Basin in the central Philippines. This is a Tertiary basin with up to 30,000 ft of sedimentary fill. With numerous surface oil and gas manifestations known as early as 1888, the area was the site of the first attempts to establish commercial petroleum production in the country. Over the past 100 years, more than 200 wells have been drilled in the basin. Several of these have yielded significant oil and gas shows. Production, albeit noncommercial in scale, has been demonstrated to be present in some places. A review of past exploration data reveals that many of the earlier efforts failed due to poorly located tests from both structural and stratigraphic standpoints. Poor drilling and completion technology and lack of funding compounded the problems of early explorationists. Because of this, the basin remains relatively underexplored. A recent assessment by COPLEX and E.F. Durkee and Associates demonstrates the presence of many untested prospects in the basin. These prospects may contain recoverable oil and gas potential on the order of 5 to 10 MMBO onshore and 25 to 100 MMBO offshore. With new exploration ideas, innovative development concepts, and the benefit of modern technology, commercial oil and gas production from the basin may yet be realized.

  7. Generation and Migration of Natural Gas in Miocene Strata, Offshore Southeastern Korea

    NASA Astrophysics Data System (ADS)

    Son, Byeong-Kook

    2016-04-01

    Natural gas and condensate are produced from Miocene strata of the Tertiary marine basin, called Ulleung Basin, which is located offshore southeastern Korea. Petroleum system in the basin has not been fully understood, because effective source rocks have not been identified in the area. However, 1-D petroleum system modelling and isotope data indicate that the source rock of the natural gas and condensate might be present at deeper strata than 5,000 m in the basin. In addition, the analysis of diamondoids in the condensate shows that the gas was transformed from type II kerogen. Based on this source rock information and other geological data, 2-D petroleum system modelling was conducted on two cross sections in the southwestern margin of the basin. The 2-D models show two phase generation and migration, which are caused by the geometry of source bed and the maturity level of each pod of the bed. In addition, the accumulation of hydrocarbon is constrained greatly by the timing of development of the regional seal. The first generation and migration of oil and gas begins with a high rate of sedimentation at a deeply and early buried pod of the source bed at 15 Ma. The hydrocarbon, however, migrates upward and diffuses toward the surface. The second generation and migration occurs at around 11 Ma from the other pod of the source bed. This hydrocarbon migrates updip toward anticlines and accumulates into the traps of anticlines. On the other hand, the model shows that the generation and migration is dominated by gas, rather than oil. This model indicates that the accumulation of hydrocarbon can be completed only by the proper and sophisticated combination of the geological elements and the timing of hydrocarbon migration in time and space. This 2-D feature of generation and migration is supported by additional 1-D models of two pseudo-wells drilled on the 2-D section.

  8. Mapping Active Faults and Tectonic Geomorphology offshore central California

    NASA Astrophysics Data System (ADS)

    Johnson, S. Y.; Watt, J. T.; Hart, P. E.; Sliter, R. W.; Wong, F. L.

    2009-12-01

    In June 2008, and July 2009, the USGS conducted two high-resolution, marine, seismic-reflection surveys across the continental shelf and upper slope between Piedras Blancas and Point Sal, central California, in order to better characterize regional earthquake sources. More than 1,300 km of single-channel seismic data were acquired aboard the USGS R/V Parke Snavely using a 500-joule mini-sparker source fired at a 0.5-second shot interval and recorded with a 15-meter streamer. Most tracklines were run perpendicular to the coast at 800-meter spacing, extending from the nearshore (~ 10-15 m water depth) to as far as 20 km offshore. Sub-bottom imaging varies with substrate, ranging from outstanding (100 to 150 m of penetration) in inferred Quaternary shallow marine, shelf and upper slope deposits to poor (0 to 10 m) in the Mesozoic basement rocks. Marine magnetic data were collected simultaneously on this survey, and both data sets are being integrated with new aeromagnetic data, publicly available industry seismic-reflection data, onshore geology, seismicity, and high-resolution bathymetry. Goals of the study are to map geology, structure, and sediment distribution; to document fault location, length, segmentation, shallow geometry and structure; and to identify possible sampling targets for constraining fault slip rates, earthquake recurrence, and tsunami hazard potential. The structure and tectonic geomorphology of the >100-km-long, right-lateral, Hosgri fault zone and its connections to the Los Osos, Pecho, Oceano and other northwest-trending inboard faults are the focus of this ongoing work. The Hosgri fault forms the eastern margin of the offshore Santa Maria basin and coincides in places with the outer edge of the narrow (5- to 15-km-wide), structurally complex continental shelf. The Hosgri is imaged as a relatively continuous, vertical fault zone that extends upward to the seafloor; varies significantly and rapidly along strike; and incorporates numerous

  9. California State Waters Map Series--Offshore of Ventura, California

    USGS Publications Warehouse

    Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Kvitek, Rikk G.; Greene, H. Gary; Krigsman, Lisa M.; Endris, Charles A.; Seitz, Gordon G.; Gutierrez, Carlos I.; Sliter, Ray W.; Erdey, Mercedes D.; Wong, Florence L.; Yoklavich, Mary M.; Draut, Amy E.; Hart, Patrick E.

    2013-01-01

    In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Ventura map area lies within the Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges, and the region is presently undergoing north-south shortening. The city of Ventura is the major cultural center in the map area. The Ventura River cuts through Ventura, draining the Santa Ynez Mountains and the coastal hills north of Ventura. Northwest of Ventura, the coastal zone is a narrow strip containing highway and railway transportation corridors and a few small residential clusters. Rincon Island, an island constructed for oil and gas production, lies offshore of Punta Gorda. Southeast of Ventura, the coastal zone consists of the mouth and broad, alluvial plains of the Santa Clara River

  10. Geophysical basin structure of the Cotonou (Dahomey/Benin) basin, West African Gulf of Guinea

    SciTech Connect

    Babalola, O.O. )

    1990-05-01

    The frontier Cotonou basin (or Dahomey/Benin embayment), situated west of the prolific Niger Delta basin, appears from seismic, gravity, and aeromagnetic interpretation, as a series of grabens and troughs confined on the west and east by the Romanche and the Chain fracture zones, respectively. The Keta trough of the western basin rim was formed by a 2700-m southeasterly downthrow of the Adina fault. This trough is separated by a north-northeasterly fault from the Lome-Anecho gravity high. Eastward, the arcuate Allada-Adjohon trough is abutted on its southern flank by the northwest-trending Nokue-Afowo trough and separated from the northwesterly Ikorodu trough by the 50-km-wide aeromagnetically inferred ro-Otta ridge. The Ikorodu trough is adjoined on the northwest by the Aiyetoro trough and on the southeast by the Yemoja offshore graben trending east northeast as the Seme oil-field structural trend. North of the regional northeasterly axial, gravity positive, structural divide (the continental precursor of the Charcot fracture zone) a series of half-grabens (notably the Aplahoue, Bohicon, and Keiou troughs), normal faulted eastward and downthrown in the west, dominate the landward western rim of the Cotonou basin. Graben-bounding faults control the upper valleys of the basin drainage, converge toward the regional intrabasin structural trend and continue into the Fenyi-koe fault and the Charcot fracture zone. These faults resulted from brittle dextral shear of continental crust oblique to local, preexisting north-northeast structural trends. In the eastern basin rim, preexisting north-northwest structural trends influenced the shearing stress regime to generate small, shallow, structurally bounded, east-northeast- and north-northwest trending grabens.

  11. Tsunami and seiche-triggered deformation within offshore sediments

    NASA Astrophysics Data System (ADS)

    Alsop, G. Ian; Marco, Shmuel

    2012-06-01

    Most studies of tsunami and seiche related deposits have focussed on coastal and near coastal zones which are most readily accessible, with few investigations of deeper water settings and the potential soft-sediment deformation effects of such waves. The Late Pleistocene Lisan Formation outcropping to the west of the Dead Sea contains superb examples of sedimentary slump folds formed in water depths of < 100 m. We have collected new structural data from an individual horizon that demonstrate that these gravity-driven slumps may be coaxially refolded and reworked by sheared folds and thrusts verging both back up and then down the palaeoslope. This suggests that it is possible to generate upslope flow of material in some circumstances. A progressive increase in reworking and shearing is developed up through the folded sediment, culminating in a breccia layer that is capped by a thin, typically graded horizon of undeformed silt and sand. We suggest that these sequentially reworked deposits are consistent with seismically triggered tsunami and seiche waves that would flow back and forth across the main slump horizon triggered by the same earthquake. The overlying sands and silts that infill local topography are considered to be deposited from turbid suspension during cessation of wave action and represent homogenite deposits. Although tsunami and seiche waves have previously been both numerically modelled and directly witnessed in the Dead Sea Basin, this study forms the first detailed structural analysis and interpretation of potential reworking associated with such waves in offshore settings, where the potential for preservation in the geological record is increased.

  12. Arctic and offshore research. Technology status report

    SciTech Connect

    Not Available

    1984-10-01

    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.

  13. Shelf response to intense offshore wind

    NASA Astrophysics Data System (ADS)

    Grifoll, Manel; Aretxabaleta, Alfredo L.; Espino, Manuel

    2015-09-01

    Cross and along-shelf winds drive cross-shelf transport that promotes the exchange of tracers and nutrients to the open sea. The shelf response to cross-shelf winds is studied in the north shelf of the Ebro Delta (Mediterranean Sea), where those winds are prevalent and intense. Offshore winds in the region exhibit strong intensities (wind stress larger than 0.8 Pa) during winter and fall. The monthly average flow observed in a 1 year current meter record at 43.5 m was polarized following the isobaths with the along-shelf variability being larger than the cross-shelf. Prevalent southwestward along-shelf flow was induced by the three-dimensional regional response to cross-shelf winds and the coastal constraint. Seaward near-surface velocities occurred predominantly during offshore wind events. During intense wind periods, the surface cross-shelf water transport exceeded the net along-shelf transport. During typically stratified seasons, the intense cross-shelf winds resulted in a well-defined two-layer flow and were more effective at driving offshore transport than during unstratified conditions. While transfer coefficients between wind and currents were generally around 1%, higher cross-shelf transfer coefficients were observed in the near-inertial band. The regional extent of the resulting surface cold water during energetic cross-shelf winds events was concentrated around the region of the wind jet. Cross-shelf transport due to along-shelf winds was only effective during northeast wind events. During along-shelf wind conditions, the transport was estimated to be between 10 and 50% of the theoretical Ekman transport.

  14. Evolution and hydrocarbon potential of offshore Pinar Del Rio area, Southern Gulf of Mexico

    SciTech Connect

    Tenreyro-Perez, R.; Lopez-Rivera, J.G.; Fernandez-Carmona, J.; Lopez-Quintero, J.O.

    1996-09-01

    The evolution of Southeast Gulf of Mexico comprises three main periods: pre-orogenic, syn-orogenic and post-orogenic. During pre-orogenic time, from Lower Jurassic to Campanian, the stages are the rift of Pangaea and the thermal subsidence (or drift). In drift stage two domains interacted in the space; the carbonate platforms (Bahamas, Yucatan, Organos and others), and the deepwater basins. These fluctuations were dictated by the differential subsidence and horizontal displacements of basement blocks as well as by the eustatic movements of the ocean. The Organos platform, for example, was entirely drowned since Upper Jurassic and the sedimentation continued in deepwater environment. The collision between Great Antilles Volcanic Arc and the continental margins since Upper Cretaceous modeled the Cuban orogen. Here, the southern facies thrusted over the northern section with simultaneous strike-slip movements. The interaction suddenly ceased in Eocene. The source rock levels are considerably more frequent in the deepwater domain than in the platforms. The Lower and Upper Jurassic as well as Lower and Middle Cretaceous horizons contain very high levels of organic matter. The offshore seismic shows the transition from the thrusted belt to the foreland basin with a typical triangle zone configuration. Reservoirs are expected in the Cretaceous section covered by seals conformed by early foreland basin sediments of Upper Cretaceous-Paleocene age. Foothill structures has a great potential for hydrocarbon exploration.

  15. California State Waters Map Series: offshore of Santa Barbara, California

    USGS Publications Warehouse

    Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Greene, H. Gary; Krigsman, Lisa M.; Kvitek, Rikk G.; Dieter, Bryan E.; Endris, Charles A.; Seitz, Gordon G.; Sliter, Ray W.; Erdey, Mercedes D.; Gutierrez, Carlos I.; Wong, Florence L.; Yoklavich, Mary M.; Draut, Amy E.; Hart, Patrick E.; Conrad, James E.; Cochran, Susan A.

    2013-01-01

    utilized Santa Barbara coastal zone, including Arroyo Burro Beach Park, Leadbetter Beach, East Beach, and “Butterfly Beach.” There are ongoing coastal erosion problems associated with both development and natural processes; between 1933–1934 and 1998, cliff erosion in the map area occurred at rates of about 0.1 to 1 m/yr, the largest amount (63 m) occurring at Arroyo Burro in the western part of the map area. In addition, development of the Santa Barbara Harbor, which began in 1928, lead to shoaling west of the harbor as the initial breakwater trapped sand, as well as to coastal erosion east of the harbor. Since 1959, annual harbor dredging has mitigated at least some of the downcoast erosion problems. The Offshore of Santa Barbara map area lies in the central part of the Santa Barbara littoral cell, which is characterized by littoral drift to the east-southeast. Drift rates have been estimated to be about 400,000 tons/yr at Santa Barbara Harbor. Sediment supply to the western and central parts of the littoral cell, including the map area, is largely from relatively small transverse coastal watersheds. Within the map area, these coastal watersheds include (from east to west) San Ysidro Creek, Oak Creek, Montecito Creek, Sycamore Creek, Mission Creek, Arroyo Burro, and Atascadero Creek. The Ventura and Santa Clara Rivers, the mouths of which are about 40 to 50 km southeast of Santa Barbara, are much larger sediment sources. Still farther east, eastward-moving sediment in the littoral cell is trapped by Hueneme and Mugu Canyons and then transported to the deep-water Santa Monica Basin. The offshore part of the map area consists of a relatively flat and shallow continental shelf, which dips gently seaward (about 0.4° to 0.8°) so that water depths at the 3-nautical-mile limit of California’s State Waters are about 45 m in the east and about 75 m in the west. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north

  16. Progressive fracture of composite offshore risers

    SciTech Connect

    Chamis, C.C.; Minnetyan, L.

    1995-08-01

    Structural durability/damage tolerance characteristics of a pressurized fiber composite tube designed as an offshore oil production riser is investigated via computational simulation. The composite structure is made of graphite/epoxy angle plies and S-glass/epoxy hoop plies. An integrated computer code that accounts for all possible failure modes is utilized for the simulation of composite structural degradation under loading. Damage initiation, growth, accumulation, and propagation to structural fracture are included in the simulation. Results show the structural degradation stages due to pressurization of a composite riser and illustrate the use of computational simulation for the investigation of a composite tube.

  17. Aluminium alloys for offshore drilling systems

    SciTech Connect

    Fine, G.M.; Basovich, V.S.; Pisarnitsky, A.D.; Jemetz, B.V.; Mazurova, L.D.; Gelfgat, M.Ya.

    1995-12-31

    This paper presents the experience gained in the USSR (now CIS) over many years in the use of Aluminum Drill Pipe (ADP). The main advantages of aluminum over steel for drill pipe applications are discussed. Methods of fabricating aluminum pipes with steel tool joints are explained. The problems of abrasion and corrosion resistance are presented. Recent experience testing ADP after exposure to the offshore environment have shown negligible reduction in fatigue life. It is now considered possible to design a slimline riser in aluminum for water depths of 3--4 kilometers.

  18. Offshore installation and maintenance of submersible pumps

    SciTech Connect

    Verdina, G.G.

    1983-01-01

    Pertamina/IIAPCO operates a large offshore production complex in the Southeast Sumatra Contract Area of Indonesia. The use of submersible centrifugal electric pumps both for artificial lift and for pipeline transfer of produced fluids has played an important role in the success enjoyed by this contract area during its 10-year producing life. This paper describes the conditions and considerations contributing to the initial selection and eventual standardized use of these pumps by the company. Also included are a discussion of operational experience gained and a summary of the submersible pumps' performance record.

  19. Platform evaluation of an offshore field

    SciTech Connect

    Huang, K.L.; Saleri, N.G.; Al-Khowaiter, A.O.

    1995-10-01

    A numerical study of an offshore field was performed to evaluate the relative performance of horizontal versus conventional wells, and various well completion/placement/production scenarios for a six-well platform. The results presented in this paper are found to be counterintuitive. While horizontal/high slant wells showed delayed gas and/or water breakthroughs, the overall platform performance remained largely insensitive to well configuration (horizontal versus conventional). Well placement, completion interval, and production strategy after breakthrough were identified to be the critical parameters in determining the performance of the platform. The study results favor conventional completions for this particular six-well platform.

  20. Along-shore variations of offshore flow

    NASA Astrophysics Data System (ADS)

    Moore, Erin; Mahrt, L.

    2003-02-01

    Using eddy correlation data collected by the LongEZ research aircraft, the adjustment of atmospheric flow downstream from a coastline is examined. Along-shore variation of the turbulence over the water is generated by the varying width of the upstream land strip between the sea and inland water. Over the coastal zone, the turbulence is strongest downstream from the widest part of land. The along-shore variation of the turbulence decreases with increasing sea fetch due to horizontal mixing. In other terms, the footprint of the flux farther offshore includes a larger width of upstream land. Beyond 5 km sea fetch, the along-shore variation becomes small.

  1. Deep water riser system for offshore drilling

    SciTech Connect

    Potts, H.L.

    1984-05-15

    A buoyant riser system for use in a deep water offshore drilling environment is anchored by a system of compliant guys below the active weather zone of the sea. A controllably buoyant housing of the system is submerged at a depth that is readily accessible to divers and includes a blow-out preventer (BOP) from which a suspended sub-riser leads to a well bore to which the sub-riser is coupled. Above the housing, a riser suspended from a floating drill rig is coupled to the BOP thereby communicating the drill rig directly with the well bore for drilling and well completion operations.

  2. Calculator program helps set offshore design criteria

    SciTech Connect

    Tran, V.B.

    1983-01-10

    Describes a new program for the Hewlett-Packard HP 41C (or HP-41C) hand-held programmable calculator which predicts the design criteria for building offshore facilities. Points out that the ''wind and wave'' (WIWA) program can quickly provide the calculations necessary for proper design involving wind forces, wave forces, and stress acting on the hydrostatic pressure case of a submerged system. Presents a flow diagram of the program and the program listing. Explains the equations used as the basis of the program.

  3. Hydrocarbon potential of the Lamu basin of south-east Kenya

    SciTech Connect

    Nyagah, K.; Cloeter, J.J.; Maende, A. )

    1996-01-01

    The Lamu basin occupies the coastal onshore and offshore areas of south-east Kenya. This fault bounded basin formed as a result of the Paleozoic-early Mesozoic phase of rifting that developed at the onset of Gondwana dismemberment. The resultant graben was filled by Karroo (Permian-Early Jurassic) continental siliciclastic sediments. Carbonate deposits associated with the Tethyan sea invasion, dominate the Middle to Late Jurassic basin fill. Cessation of the relative motion between Madagascar and Africa in the Early Cretaceous, heralded passive margin development and deltaic sediment progradation until the Paleogene. Shallow seas transgressed the basin in the Miocene when another carbonate regime prevailed. The basin depositional history is characterized by pulses of transgressive and regressive cycles, bounded by tectonically enhanced unconformities dividing the total sedimentary succession into discrete megasequences. Source rock strata occur within Megasequence III (Paleogene) depositional cycle and were lowered into the oil window in Miocene time, when the coastal parts of the basin experienced the greatest amount of subsidence. The tectono-eustatic pulses of the Tertiary brought about source and reservoir strata into a spatial relationship in which hydrocarbons could be entrapped. A basement high on the continental shelf has potential for Karroo sandstone and Jurassic limestone reservoirs. Halokinesis of Middle Jurassic salt in Miocene time provides additional prospects in the offshore area. Paleogene deltaic sands occur in rotated listric fault blacks. A Miocene reef Play coincides with an Eocene source rock kitchen.

  4. Hydrocarbon potential of the Lamu basin of south-east Kenya

    SciTech Connect

    Nyagah, K.; Cloeter, J.J.; Maende, A.

    1996-12-31

    The Lamu basin occupies the coastal onshore and offshore areas of south-east Kenya. This fault bounded basin formed as a result of the Paleozoic-early Mesozoic phase of rifting that developed at the onset of Gondwana dismemberment. The resultant graben was filled by Karroo (Permian-Early Jurassic) continental siliciclastic sediments. Carbonate deposits associated with the Tethyan sea invasion, dominate the Middle to Late Jurassic basin fill. Cessation of the relative motion between Madagascar and Africa in the Early Cretaceous, heralded passive margin development and deltaic sediment progradation until the Paleogene. Shallow seas transgressed the basin in the Miocene when another carbonate regime prevailed. The basin depositional history is characterized by pulses of transgressive and regressive cycles, bounded by tectonically enhanced unconformities dividing the total sedimentary succession into discrete megasequences. Source rock strata occur within Megasequence III (Paleogene) depositional cycle and were lowered into the oil window in Miocene time, when the coastal parts of the basin experienced the greatest amount of subsidence. The tectono-eustatic pulses of the Tertiary brought about source and reservoir strata into a spatial relationship in which hydrocarbons could be entrapped. A basement high on the continental shelf has potential for Karroo sandstone and Jurassic limestone reservoirs. Halokinesis of Middle Jurassic salt in Miocene time provides additional prospects in the offshore area. Paleogene deltaic sands occur in rotated listric fault blacks. A Miocene reef Play coincides with an Eocene source rock kitchen.

  5. Sedimentary architecture of a Plio-Pleistocene proto-back-arc basin: Wanganui Basin, New Zealand

    NASA Astrophysics Data System (ADS)

    Proust, Jean-Noël; Lamarche, Geoffroy; Nodder, Scott; Kamp, Peter J. J.

    2005-11-01

    The sedimentary architecture of active margin basins, including back-arc basins, is known only from a few end-members that barely illustrate the natural diversity of such basins. Documenting more of these basins types is the key to refining our understanding of the tectonic evolution of continental margins. This paper documents the sedimentary architecture of an incipient back-arc basin 200 km behind the active Hikurangi subduction margin, North Island, New Zealand. The Wanganui Basin (WB) is a rapidly subsiding, Plio-Pleistocene sedimentary basin located at the southern termination of the extensional back-arc basin of the active Central Volcanic Region (TVZ). The WB is asymmetric with a steep, thrust-faulted, outer (arc-ward) margin and a gentle inner (craton-ward) margin. It contains a 4-km-thick succession of Plio-Pleistocene sediments, mostly lying offshore, composed of shelf platform sediments. It lacks the late molasse-like deposits derived from erosion of a subaerial volcanic arc and basement observed in classical back-arc basins. Detailed seismic stratigraphic interpretations from an extensive offshore seismic reflection data grid show that the sediment fill comprises two basin-scale mega-sequences: (1) a Pliocene (3.8 to 1.35 Ma), sub-parallel, regressive "pre-growth" sequence that overtops the uplifted craton-ward margin above the reverse Taranaki Fault, and (2) a Pleistocene (1.35 Ma to present), divergent, transgressive, "syn-growth" sequence that onlaps: (i) the craton-ward high to the west, and (ii) uplifted basement blocks associated with the high-angle reverse faults of the arc-ward margin to the east. Along strike, the sediments offlap first progressively southward (mega-sequence 1) and then southeastward (mega-sequence 2), with sediment transport funnelled between the craton- and arc-ward highs, towards the Hikurangi Trough through the Cook Strait. The change in offlap direction corresponds to the onset of arc-ward thrust faulting and the rise of

  6. 47 CFR 22.1007 - Channels for offshore radiotelephone systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Channels for offshore radiotelephone systems. 22.1007 Section 22.1007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Offshore Radiotelephone Service § 22.1007 Channels for...

  7. Flying in, Flying out: Offshore Teaching in Higher Education

    ERIC Educational Resources Information Center

    Seah, Wee Tiong; Edwards, Julie

    2006-01-01

    This paper discusses the relatively new phenomenon of university education faculties offering offshore education. The analogy, "flying in, flying out" captures the intensity of such offshore experiences for visiting academics, and contrasts their professional experiences against expatriate academics. This paper reports on case studies of two…

  8. 76 FR 62817 - National Offshore Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-11

    ...The National Offshore Safety Advisory Committee (NOSAC) will meet on November 15, 2011, in Houston, Texas to discuss various issues related to safety of operations and other matters affecting the oil and gas offshore industry. The meeting will be open to the...

  9. 2014-2015 Offshore Wind Technologies Market Report

    SciTech Connect

    Smith, Aaron

    2015-11-18

    This presentation provides an overview of progress toward offshore wind cost reduction in Europe and implications for the U.S. market. The presentation covers an overview of offshore wind developments, economic and performance trends, empirical evidence of LCOE reduction, and challenges and opportunities in the U.S. market.

  10. 75 FR 23582 - Annular Casing Pressure Management for Offshore Wells

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-04

    ... published the proposed rule Annular Casing Pressure Management for Offshore Wells (74 FR 38147). The comment... the published proposed rule 1010-AD47 Annular Casing Pressure Management for Offshore Wells (74 FR... subsea wellhead. (3) hybrid well, a riser or the production casing pressure is greater than 100...

  11. 76 FR 39410 - National Offshore Safety Advisory Committee; Vacancies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... construction of offshore exploration and recovery facilities; (c) One member representing employees of...-2011-0539) in the Search box, and click ``Go.'' Please do not post your resume on this site. Dated... SECURITY Coast Guard National Offshore Safety Advisory Committee; Vacancies AGENCY: Coast Guard,...

  12. 46 CFR 175.115 - Applicability to offshore supply vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Applicability to offshore supply vessels. 175.115 Section 175.115 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) GENERAL PROVISIONS § 175.115 Applicability to offshore supply vessels....

  13. 75 FR 30845 - National Offshore Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard National Offshore Safety Advisory Committee AGENCY: Coast Guard, DHS. ACTION: Notice... National Offshore Safety Advisory Committee (NOSAC) to discuss items listed in the agenda as well as...

  14. 75 FR 47311 - National Offshore Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-05

    ... SECURITY Coast Guard National Offshore Safety Advisory Committee AGENCY: Coast Guard, DHS. ACTION: Notice of open teleconference meeting. SUMMARY: The National Offshore Safety Advisory Committee (NOSAC) will meet by teleconference to discuss items related to safety of operations and other matters affecting...

  15. 46 CFR 111.105-33 - Mobile offshore drilling units.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Mobile offshore drilling units. 111.105-33 Section 111.105-33 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Hazardous Locations § 111.105-33 Mobile offshore drilling units. (a) Applicability. This section applies to...

  16. Offshore Oil: Environmental Impacts on Land and Sea

    ERIC Educational Resources Information Center

    Baldwin, Pamela L.

    1974-01-01

    Presents a counter position to that provided in SE 512 127 in which the author emphasizes that there are too many problems yet to be solved (related to offshore oil development) to proceed with full-scale development of offshore oil drilling. (PEB)

  17. Wind Resource Mapping for United States Offshore Areas: Preprint

    SciTech Connect

    Elliott, D.; Schwartz, M.

    2006-06-01

    The U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) is producing validated wind resource maps for priority offshore regions of the United States. This report describes the methodology used to validate the maps and to build a Geographic Information Systems (GIS) database to classify the offshore wind resource by state, water depth, distance from shore, and administrative unit.

  18. International Collaboration on Offshore Wind Energy Under IEA Annex XXIII

    SciTech Connect

    Musial, W.; Butterfield, S.; Lemming, J.

    2005-11-01

    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.

  19. 76 FR 77223 - Enbridge Offshore Pipelines (UTOS); Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Enbridge Offshore Pipelines (UTOS); Notice of Filing Take notice that on November 30, 2011, Enbridge Offshore Pipelines (UTOS) submitted a request for a waiver of the...

  20. CHEMICAL COMPOSITION OF PRODUCED WATER AT SOME OFFSHORE OIL PLATFORMS

    EPA Science Inventory

    The effectiveness of produced water treatment was briefly studied in offshore oil and gas extraction operations in Cook Inlet, Alaska, and the Gulf of Mexico. Three offshore oil extraction facilities were examined in the Cook Inlet production field, and seven platforms were studi...

  1. 75 FR 65025 - National Offshore Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-21

    ...The National Offshore Safety Advisory Committee (NOSAC) will meet to discuss items related to safety of operations and other matters affecting the oil and gas offshore industry. The purpose of this meeting is to review and discuss reports and recommendations received from the various NOSAC subcommittees. The Committee will then use this information to formulate recommendations to the agency.......

  2. 75 FR 80064 - National Offshore Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-21

    ...The National Offshore Safety Advisory Committee (NOSAC) will meet by teleconference to discuss items related to safety of operations and other matters affecting the oil and gas offshore industry. The purpose of this meeting is to review and discuss reports and recommendations received from the two NOSAC subcommittees and to address two new tasks for the Committee. This meeting will be open to......

  3. 46 CFR 90.10-40 - Offshore supply vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Offshore supply vessels. 90.10-40 Section 90.10-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 90.10-40 Offshore supply vessels. (a) An...

  4. 46 CFR 90.10-40 - Offshore supply vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Offshore supply vessels. 90.10-40 Section 90.10-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 90.10-40 Offshore supply vessels. (a) An...

  5. Reinterpretation of the Northern Terminus of the San Andreas Transform System: Implications for basin development and hydrocarbon exploration

    SciTech Connect

    Foland, S.S. ); Enzor, K.J. )

    1994-07-01

    The northern San Andreas transform system was studied to evaluate the tectonic history of offshore Point Arena basin, northern California. The Point Arena basin lies 250 km north of San Francisco and encompasses 8500 km[sup 2] on the outer continental shelf. It is a tertiary basin formed during Eocene subduction and overprinted by Pliocene-Pleistocene strike-slip motion of the San Andreas fault system. Interpretation of the data yields a new tectonic model for the northern San Andreas fault system and Point Arena basin. Previous models curved the fault system east parallel to the coast, intersecting faults exposed on Point Delgada, and then bending the fault sharply west to join the Mendocino triple junction. The new model projects the San Andreas fault system due northwest, straight into the offshore basin, as a series of parallel faults aligned with the onshore fault trace to directly intersect the triple junction. The new interpretation is supported by aeromagnetic data, which indicates the basin is divided by a major northwest-trending structural boundary and floored by two distinct basement types (Mesozoic Salinian granies and Jurassic Franciscan metasediments). The latest seismic data contain enough information to determine the genesis and orientation of the offshore fault system and associated folds. Basin modeling indicates hydrocarbon generation has occurred in the Miocene source beds. The model estimates the Point Arena basin contains multibillion barrel potential trapped in large antiforms associated with the through-going San Andreas system. Integration of all geotechnical data allowed reinterpretation of the tectonic history, and produced an enhanced understanding of Point Arena basin.

  6. Site characterisation of a basin-scale CO2 geological storage system: Gippsland Basin, southeast Australia

    NASA Astrophysics Data System (ADS)

    Gibson-Poole, C. M.; Svendsen, L.; Underschultz, J.; Watson, M. N.; Ennis-King, J.; van Ruth, P. J.; Nelson, E. J.; Daniel, R. F.; Cinar, Y.

    2008-06-01

    Geological storage of CO2 in the offshore Gippsland Basin, Australia, is being investigated by the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) as a possible method for storing the very large volumes of CO2 emissions from the nearby Latrobe Valley area. A storage capacity of about 50 million tonnes of CO2 per annum for a 40-year injection period is required, which will necessitate several individual storage sites to be used both sequentially and simultaneously, but timed such that existing hydrocarbon assets will not be compromised. Detailed characterisation focussed on the Kingfish Field area as the first site to be potentially used, in the anticipation that this oil field will be depleted within the period 2015 2025. The potential injection targets are the interbedded sandstones of the Paleocene-Eocene upper Latrobe Group, regionally sealed by the Lakes Entrance Formation. The research identified several features to the offshore Gippsland Basin that make it particularly favourable for CO2 storage. These include: a complex stratigraphic architecture that provides baffles which slow vertical migration and increase residual gas trapping and dissolution; non-reactive reservoir units that have high injectivity; a thin, suitably reactive, lower permeability marginal reservoir just below the regional seal providing mineral trapping; several depleted oil fields that provide storage capacity coupled with a transient production-induced flow regime that enhances containment; and long migration pathways beneath a competent regional seal. This study has shown that the Gippsland Basin has sufficient capacity to store very large volumes of CO2. It may provide a solution to the problem of substantially reducing greenhouse gas emissions from future coal developments in the Latrobe Valley.

  7. Anisotropy from SKS splitting across the Pacific-North America plate boundary offshore southern California

    NASA Astrophysics Data System (ADS)

    Ramsay, Joseph; Kohler, Monica D.; Davis, Paul M.; Wang, Xinguo; Holt, William; Weeraratne, Dayanthie S.

    2016-07-01

    SKS arrivals from ocean bottom seismometer (OBS) data from an offshore southern California deployment are analyzed for shear-wave splitting. The project involved 34 OBSs deployed for 12 months in a region extending up to 500 kilometers west of the coastline into the oceanic Pacific plate. The measurement process consisted of removing the effects of anisotropy using a range of values for splitting fast directions and delay times to minimize energy along the transverse seismometer axis. Computed splitting parameters are unexpectedly similar to onland parameters, exhibiting WSW-ENE fast polarization directions and delays between 0.8 and 1.8 s, even for oceanic plate sites. This is the first SKS splitting study to extend across the entire boundary between the North America and Pacific plates, into the oceanic part of the Pacific plate. The splitting results show that the fast direction of anisotropy on the Pacific plate does not align with absolute plate motion (APM), and they extend the trend of anisotropy in southern California an additional 500 km west, well onto the oceanic Pacific plate. We model the finite strain and anisotropy within the asthenosphere associated with density-buoyancy driven mantle flow and the effects of APM. In the absence of plate motion effects, such buoyancy driven mantle flow would be NE-directed beneath the Pacific plate observations. The best-fit patterns of mantle flow are inferred from the tomography-based models that show primary influences from foundering higher-density zones associated with the history of subduction beneath North America. The new offshore SKS measurements, when combined with measurements onshore within the plate boundary zone, indicate that dramatic lateral variations in density-driven upper mantle flow are required from offshore California into the plate boundary zone in California and western Basin and Range.

  8. Structural character of Hosgri fault zone and adjacent areas in offshore central California

    SciTech Connect

    Crouch, J.K.; Bachman, S.B.

    1987-05-01

    The Hosgri fault zone extends from the east-west Transverse Ranges structures near Point Arguello northward for more than 150 km to the offshore area near San Simeon Point. The fault zone is seismically active and consists chiefly of a continuous series of eastside-up thrust and high-angle reverse faults. East of the fault zone, Miocene Monterey and volcanic rocks, along with underlying pre-Miocene strata, have been tightly folded as a result of low-angle imbricate thrust faulting during post-Miocene time. These highly deformed strata have been uplited and truncated along the inner shelf. Immediately west of the Hosgria fault zone, similar Monterey and older rocks, which are less folded, conformably underlie Pliocene and younger basinal strata at structural levels that are generally 1200 to 2000 m deeper than correlative strata east of the Hosgri fault zone. Following its discovery in 1971, the Hosgri fault zone was characterized by subsequent investigators as a northwest-trending fault that was part of the San Andreas system of strike-slip faults, with disagreements on the timing and amount of right-lateral offset along the fault zone. However, modern offshore seismic-reflection data, earthquake focal-mechanism studies, and recently available offshore well information suggest that the Hosgri fault zone is instead a major imbricate thrust zone. Detailed structural analyses along part of the Hosgri fault zone suggest that little, if any, strike-slip offset has occurred along this structural trend since its post-Miocene inception. Nevertheless, the Hosgri fault zone itself can be interpreted to be a product of the larger overall San Andreas transform system in that compression has developed because the San Andreas is not parallel to the Pacific-North American plate motion.

  9. Offshore Structure of the Cascadia Subduction Zone from Full-wave Tomography

    NASA Astrophysics Data System (ADS)

    Gao, H.

    2014-12-01

    We construct a preliminary offshore model of the crust and uppermost mantle at the Cascadia subduction zone using a full-wave tomographic method. We include the ocean bottom seismometers deployed by the Cascadia Initiative community experiment and Neptune Canada from 2011-2013, and the available broadband stations on land. We have extracted the empirical Green's functions from continuous seismic records on the vertical components of the OBS and inland station pairs with a frequency-time normalization method, which provide useful Rayleigh-wave signals within the periods of 7-50 s. We have also selected ~50 regional earthquakes between 2011-2013 offshore of the Cascadia subduction zone, which generated useful surface-wave signals up to 75 s period. We simulate wave propagation within a 3D Earth structure using a finite-difference method to generate a station Strain Greens Tensor database and synthetic waveforms. Rayleigh wave phase delays are obtained by cross-correlating the observed and synthetic waveforms. The sensitivity kernels of Rayleigh waves on the perturbations of Vp and Vs are calculated based on the Strain Greens Tensor database. We then invert for the velocity perturbation from the reference model and progressively improve the model resolution. Our preliminary full-wave tomographic imaging using the EGFs and earthquake Rayleigh waves shows: (1) Segmented low-velocity anomalies along the forearc, which are spatially correlated with the patterns of offshore basins and high slip patches; (2) Low velocities beneath the Blanco fracture zone; (3) The distribution of pseudofaults defines the seismic velocity heterogeneities; and (4) A low-velocity zone beneath the oceanic Moho near the trench, which may indicate serpentinization of the mantle lithosphere.

  10. Ghana seeks to resume offshore production

    SciTech Connect

    Not Available

    1991-06-17

    Ghana National Petroleum Corp. (GNPC) plans a two well offshore drilling program it hopes will lead to a resumption of hydrocarbon production in the West African state. The wells will be drilled in South Tano field in the extreme western sector of Ghana's offshore area, near the boundary with Ivory Coast. If the program is successful, the state company will develop a novel floating production system to handle and export oil. Gas will provide fuel for an electrical power generating unit integrated into a floating production system. Power will move ashore through a submarine cable. North and south Tano fields were discovered by Phillips Petroleum Corp., which relinquished the acreage in 1982. The South Tano discovery well flowed 1,614 b/d of oil and 8.2 MMCfd of gas. Studies by a unit of ARCO, when it was a partner in a group that later acquired the Tano block, pegged North Tano hydrocarbons in place at 53.6 million bbl of oil and 102 bcf of gas. Braspetro, under contract with GNPC, estimated South Tano hydrocarbons in place at 82 million bbl of oil and 100 bcf of gas. GNPC is evaluating the possibility of rehabilitating Saltpond oil field about 150 miles east-northeast of North and South Tano. Saltpond has been shut in since 1985.

  11. Optimization of monopiles for offshore wind turbines.

    PubMed

    Kallehave, Dan; Byrne, Byron W; LeBlanc Thilsted, Christian; Mikkelsen, Kristian Kousgaard

    2015-02-28

    The offshore wind industry currently relies on subsidy schemes to be competitive with fossil-fuel-based energy sources. For the wind industry to survive, it is vital that costs are significantly reduced for future projects. This can be partly achieved by introducing new technologies and partly through optimization of existing technologies and design methods. One of the areas where costs can be reduced is in the support structure, where better designs, cheaper fabrication and quicker installation might all be possible. The prevailing support structure design is the monopile structure, where the simple design is well suited to mass-fabrication, and the installation approach, based on conventional impact driving, is relatively low-risk and robust for most soil conditions. The range of application of the monopile for future wind farms can be extended by using more accurate engineering design methods, specifically tailored to offshore wind industry design. This paper describes how state-of-the-art optimization approaches are applied to the design of current wind farms and monopile support structures and identifies the main drivers where more accurate engineering methods could impact on a next generation of highly optimized monopiles. PMID:25583868

  12. Thermometric well testing on the Vietnam offshore

    SciTech Connect

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

    1994-12-31

    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.

  13. U.K. offshore safety regime raises new challenges

    SciTech Connect

    Baily, M.

    1996-08-19

    In November 1995, UK operators completed implementation of the offshore safety case regime, which resulted from Lord Cullen`s inquiry into the Piper Alpha explosion of 1988. Since then a number of significant milestones have been achieved, but there are continuing challenges both for the operators of offshore installations and the regulator, the Offshore Safety Division (OSD) of the Health and Safety Executive (HSE). Recommendations from Lord Cullen`s report on the Piper Alpha disaster were far-reaching and included proposals for an extensive legislative review. They included a requirement for the submission and acceptance of a safety case document for each offshore installation, in advance of operations and underpinning goal-setting regulations covering arrangements for prevention and mitigation of fire and explosion, emergency response, offshore management, and design and construction, and for verification of integrity. The paper discusses safety cases, benefits and costs, work in progress, challenges, appraisal, and compliance.

  14. Management of offshore wastes in the United States.

    SciTech Connect

    Veil, J. A.

    1998-10-22

    During the process of finding and producing oil and gas in the offshore environment operators generate a variety of liquid and solid wastes. Some of these wastes are directly related to exploration and production activities (e.g., drilling wastes, produced water, treatment workover, and completion fluids) while other types of wastes are associated with human occupation of the offshore platforms (e.g., sanitary and domestic wastes, trash). Still other types of wastes can be considered generic industrial wastes (e.g., scrap metal and wood, wastes paints and chemicals, sand blasting residues). Finally, the offshore platforms themselves can be considered waste materials when their useful life span has been reached. Generally, offshore wastes are managed in one of three ways--onsite discharge, injection, or transportation to shore. This paper describes the regulatory requirements imposed by the government and the approaches used by offshore operators to manage and dispose of wastes in the US.

  15. Three cycles of sedimentation in ancient sedimentary basins of southern Ireland: insights from detrital zircon U-Pb ages

    NASA Astrophysics Data System (ADS)

    Fairey, Brenton; Kerrison, Aidan; Meere, Patrick; Mulchrone, Kieran; Linnemann, Ulf; Hofmann, Mandy; Gaertner, Andreas; Sonntag, Benita-Lisette; Byrne, Keith

    2016-04-01

    Previous work has shown that sedimentary rocks from the Lower Devonian Dingle Basin were uplifted and recycled by Acadian orogenic activity into the Upper Devonian Munster Basin. This is particularly applicable for sediments deposited in the western part of the Munster Basin. In the present study, a new dataset of U-Pb ages for detrital zircons has been established that spans a large geographic area which includes the Dingle and Munster basins as well as the offshore Mesozoic North Celtic Sea, South Celtic Sea, 'Goban Spur' and Fastnet basins. The study is the first of its kind in any of these sedimentary basins. The aim is to investigate whether sediments deposited in the offshore basins during the Mesozoic reflect three erosion-deposition cycles. Detritus that has undergone three sedimentary cycles would yield super-mature sediments suitable for hydrocarbon storage. Detrital zircon age spectra for Lower Devonian Dingle Basin samples indicate strong sediment input from Avalonian (~600 Ma) and Laurentian (~1.7 Ga and ~1.1 Ga) sources with some input from Caledonian orogenic sources (400-480 Ma). Detrital zircon age spectra in the western Munster Basin largely reflect input from Caledonian-aged igneous crustal input (400-480 Ma) and Laurentian sources. An Avalonian component is not detected in any of the samples from the western Munster Basin. In the central and eastern parts of the Munster Basin, detrital zircon age spectra indicate that the dominant sources of detritus are derived from Laurentia and from Caledonian igneous rocks. In contrast to the western part of the basin, age components around 600 Ma are present in some samples and represent an Avalonian source. These signals are echoed, at varying degrees, in detrital age spectra from Jurassic and Cretaceous samples of the central North Celtic Sea Basin. These age spectra also indicate a significant contribution of detritus from Avalonian terrane. The Avalonian signature is completely absent from Jurassic

  16. Intelligent system for start-up of a petroleum offshore platform.

    PubMed

    Campos, M C; Satuf, E; de Mesquita, M

    2001-01-01

    It is difficult to control and to manage the start-up of a petroleum offshore platform. In order to solve this problem an intelligent system can play an important role, since available qualitative operator and design knowledge can be easily implemented to assist the operator during start-up. This paper describes the integration of an expert system with a fuzzy controller applied to such a process. The intelligent system has many heuristic rules to implement the automation of the start-up procedures, like the opening of many on-off valves while simultaneously monitoring process variables. It also has a fuzzy controller to optimize the opening of the oil wells, in order to minimize the start-up time. This intelligent system is being implemented in the platform P-19 of Petrobras, the Brazilian oil company, in Campos Basin, Brazil. The prototype has been operating since October 1998. PMID:11515945

  17. Recent Inversion, Seismic Potential, and Neogene Kinematics of the Algerian Margin (Western Mediterranean) from Offshore Studies

    NASA Astrophysics Data System (ADS)

    Deverchere, J.; Yelles, K.; Bracene, R.; Mercier de Lepinay, B. F.; Cattaneo, A.; Medaouri, M.; Gaullier, V.; Babonneau, N.; Ratzov, G.; Boudiaf, A.; Graindorge, D.; Kherroubi, A.; Strzerzynski, P. H.; Authemayou, C.; Djellit, H.; Heddar, A.; Maradja'03; Maradja-Samra'05 Scientific Teams

    2011-12-01

    The reasons to study the Algerian margin (Western Mediterranean) are at least threefold: (1) the seismic hazard offshore is obviously present but unconstrained, (2) the way the opening of the Algerian basin occurred is highly debated, and (3) this margin represents one of the rare examples on Earth of an ongoing subduction inception. We present an overview of recent findings on the tectonic evolution of this margin, where most of the plate convergence between Africa and Europe is taken up today, mostly from cruises MARADJA and MARADJA2/SAMRA led by joint Algerian and French teams. Large, overlapping active thrust faults and folds apparently dominate the seismotectonic pattern from the Atlas domain on land to the foot of the margin offshore, with a clear segmentation. Strain is distributed across the whole area, with a significant part of the relative plate convergence taken up offshore. Fault activity offshore is tenuous and most often indirect (Plio-Quaternary growth strata, folds, uplifted basins, scars and slope breaks). Along the eastern margin, faults form stepwise, en-échelon systems on the slope and in the deep basin. Some thrusts identified turn to fault-propagation folds at the sub-surface. Thrusts interact with the sediment flux, Messinian salt and seafloor currents, forming complex structures at deep-sea fans and scarps or scars on the main slope breaks. The 2003 Mw 6.9 Boumerdes rupture is correlated segmented cumulative scarps on the slope and at the foot of the margin. Using various VHR seismic reflection and coring analyses, we show that the record of turbidite deposition since ca. 10.000 yrs can be identified and correlated over long distances within or across large segments of the margin affected by the 1954, 1980 and 2003 events. The consequences in term of earthquake size and recovery of their recurrences (identification of paleo-events) are explored and discussed. Although we cannot associate the triggering of large turbidity currents to a

  18. Rock magnetism of gas hydrate-bearing rocks in the Nankai Trough, offshore SW Japan

    NASA Astrophysics Data System (ADS)

    Kars, M. A.; Kodama, K.

    2013-12-01

    For the last decade, focus on gas hydrates has been increasing because of their potential value as an energy resource and their possible impact on climate change. Convergent margins, such as the Cascadia Margin (offshore Oregon, USA) and the Nankai Trough (offshore SW Japan) are favorable locations for the formation of gas hydrates. High amplitude bottom simulating reflectors (BSR) are often considered to be indicators of the presence of gas hydrates. Rock magnetism has also appeared to be a suitable approach. Here we focus on gas hydrate-bearing rocks from hole C0008C drilled in 2008 during the IODP Expedition 316, part of the Nankai Trough Seismogenic Experiment Zone (NanTroSEIZE) drilling project. Site C0008 is located at the slope basin seaward of the splay fault. In hole C0008C, seven gas hydrates occurrences were identified by local Cl minima from ~70 to ~170 m CSF (core depth below seafloor). We conducted a high-resolution rock magnetic study from ~70 to ~110 m CSF in order to determine the nature, size and concentration of the magnetic minerals present in the cores. As a preliminary study, about 200 discrete samples were analyzed. In addition, comparison with geochemical data and scanning electron microscope observations were made.

  19. Sea-floor geology and character offshore of Rocky Point, New York

    USGS Publications Warehouse

    Poppe, L.J.; McMullen, K.Y.; Ackerman, S.D.; Blackwood, D.S.; Irwin, B.J.; Schaer, J.D.; Lewit, P.G.; Doran, E.F.

    2010-01-01

    The U.S. Geological Survey (USGS), the Connecticut Department of Environmental Protection, and the National Oceanic and Atmospheric Administration (NOAA) have been working cooperatively to interpret surficial sea-floor geology along the coast of the Northeastern United States. NOAA survey H11445 in eastern Long Island Sound, offshore of Plum Island, New York, covers an area of about 12 square kilometers. Multibeam bathymetry and sidescan-sonar imagery from the survey, as well as sediment and photographic data from 13 stations occupied during a USGS verification cruise are used to delineate sea-floor features and characterize the environment. Bathymetry gradually deepens offshore to over 100 meters in a depression in the northwest part of the study area and reaches 60 meters in Plum Gut, a channel between Plum Island and Orient Point. Sand waves are present on a shoal north of Plum Island and in several smaller areas around the basin. Sand-wave asymmetry indicates that counter-clockwise net sediment transport maintains the shoal. Sand is prevalent where there is low backscatter in the sidescan-sonar imagery. Gravel and boulder areas are submerged lag deposits produced from the Harbor Hill-Orient Point-Fishers Island moraine segment and are found adjacent to the shorelines and just north of Plum Island, where high backscatter is present in the sidescan-sonar imagery.

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

    SciTech Connect

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

    1986-05-01

    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.

  1. Reserves in western basins

    SciTech Connect

    Caldwell, R.H.; Cotton, B.W.

    1992-06-01

    This project requires generation of producible tight gas sand reserve estimates for three western basins. The requirement is to perform such reserve estimates using industry accepted practices so that results will have high credibility and acceptance by the oil and gas industry. The ultimate goal of the project is to encourage development of the tight gas formation by industry through reduction of the technical and economic risks of locating, drilling and completing commercial gas wells. The three geological basins selected for study are the Greater Green River Basin, Uinta Basin and Piceance Basin, located in the Colorado, Utah and Wyoming Rocky Mountain region.

  2. Reserves in western basins

    SciTech Connect

    Caldwell, R.H.; Cotton, B.W.

    1992-01-01

    This project requires generation of producible tight gas sand reserve estimates for three western basins. The requirement is to perform such reserve estimates using industry accepted practices so that results will have high credibility and acceptance by the oil and gas industry. The ultimate goal of the project is to encourage development of the tight gas formation by industry through reduction of the technical and economic risks of locating, drilling and completing commercial gas wells. The three geological basins selected for study are the Greater Green River Basin, Uinta Basin and Piceance Basin, located in the Colorado, Utah and Wyoming Rocky Mountain region.

  3. A hindcast study of the extreme wave climate of offshore west Africa (WAX)

    SciTech Connect

    Cardone, V.J.; Cooper, C.K.; Szabo, D.

    1995-12-01

    This paper describes the methodology and selected results of a Joint Industry Project called WAX (West Africa Extremes) whose purpose was to develop estimates of extreme waves for the West Coast of Africa between 5 N and 15 S. Extreme waves there consist of swell propagated from distant sources associated with extratropical storms in deep southern latitudes or from episodic enhancements of anticyclonic southeast winds off South Africa. The basic steps of the hindcast method are described: storm selection, specification of wind fields, application of a directional spectral wave prediction model, model validation and external analysis of results of hindcasts of the historical storm population selected. The validation consisted of a comparison of wave model predictions and measurements of significant wave height, peak spectral period and frequency spectra during several episodes of extreme swell conditions, selected from wave measurements recorded at a platform offshore Nigeria over a two-year period (1981--82) and over a 12-month period (1990--91) by a Waverider buoy moored offshore Cabinda. It was found that despite the special difficulties of hindcasting the wind fields of Southern Hemisphere (SH) storms caused by sparsity of meteorological data, the hindcast skill exhibited in these comparisons is comparable with the good agreement typically achieved in Northern Hemisphere (NH) basins with the hindcast methodology applied. The wave model used for these hindcasts has been well validated in NH basins mainly in extreme storm regimes where the source terms which model the physical mechanisms of wave growth and dissipation dominate the model solution. The WAX extremes are derived from hindcasts of a population of 50 historical storms. The extremes are summarized for selected areas.

  4. A High Resolution Geophysical Study of the Offshore Western Gulf of Corinth Rift

    NASA Astrophysics Data System (ADS)

    McNeill, L.; Cotterill, C.; Stefatos, A.; Henstock, T.; Bull, J.; Collier, R.; Papatheodorou, G.; Georgiopoulou, A.; Ferentinos, G.

    2003-12-01

    The western Gulf of Corinth has generated recent debate in terms of distribution of extensional strain, interactions between active faults and fault geometry. Onshore data suggest that faults do not accommodate extensional strain of the magnitude suggested by geodetic measurements. Recently acquired high resolution geophysical data in the western Gulf of Corinth, including Reson Seabat 8160 50 kHz multibeam bathymetry (with sidescan collected simultaneously) and sparker and boomer seismic profiles, will allow a detailed study of faulting relationships, fault propagation history and associated sedimentological processes. Multibeam data indicate the complex axial and tributary channel pattern of the gulf as well as revealing the surface expression of active faults on both margins and within the basin centre. Several fault tips are evident, including the Aigion fault which has been surveyed in great detail with boomer lines spaced between 25-100 m. The fault tip is complex with multiple synthetic and antithetic splays. The post-lowstand transgressive surface is clearly imaged and therefore fault growth rates can be established. Gas-related features are common, including pockmarks and mud volcanoes. To the east, displacement on the eastern tip of the Eliki fault decreases rapidly offshore and a splay of the Derveni fault is observed. A major S-dipping antithetic fault opposite the Eastern Eliki fault has clear bathymetric expression and is locally associated with a prominent basement ridge. This fault may make a significant contribution to extensional strain in this part of the rift. In the centre of the basin, sediments are deformed by multiple minor faults with seafloor displacement. Ultimately, high resolution offshore interpretations can be integrated with regional datasets and existing data (e.g., geomorphic, paleoseismological and sedimentological) onshore and used to better assess rift deformation models, rift evolution and local seismic hazards.

  5. [Life and work at the petroleum industry in Campos Basin].

    PubMed

    Leite, Rose Mery dos Santos Costa

    2009-01-01

    In this paper we detach the subject of confinement as a central axle in the activity at maritime oil platforms of Campos Basin, in north region of the Rio de Janeiro state. This work reality that determines for offshore workers, as they are known, a rupture between two different moments in there lives: the period of fourteen days in the sea and the life in land per twenty one days. We adopt as material empiricist, the research carried out on this universe, detaching here the way as these professionals understand the conditions of confined work in which they are submitted. PMID:20069186

  6. Gulf of Mexico Oil and Gas Atlas Series: Play analysis of oligocene and miocene reservoirs from Texas State Offshore Waters

    SciTech Connect

    Seni, S.J.; Finley, R.J.

    1993-12-31

    The objective of the Offshore Northern Gulf of Mexico Oil and Gas Resource Atlas Series is to define hydrocarbon plays by integrating geologic and engineering data for oil and gas reservoirs with large-scale patterns of depositional basin fill and geologic age. The primary product of the program will be an oil and gas atlas set for the offshore northern Gulf of Mexico and a computerized geographical information system of geologic and engineering data linked to reservoir location. The oil and gas atlas for the Gulf of Mexico will provide a critically compiled, comprehensive reference that is needed to more efficiently develop reservoirs, to extend field limits, and to better assess the opportunities for intrafield exploration. The play atlas will provide an organizational framework to aid development in mature areas and to extend exploration paradigms from mature areas into frontier areas deep below the shelf and into deep waters of the continental slope. In addition to serving as a model for exploration and education, the offshore atlas will aid resource assessment efforts of State, Federal, and private agencies by allowing for greater precision in the extrapolation of variables within and between plays. Classification and organization of reservoirs into plays have proved to be effective in previous atlases produced by the Bureau, including the Texas oil and gas atlases, the Midcontinent gas atlas, and Central and Eastern Gulf Coast gas atlas.

  7. Geospatial characteristics of Florida's coastal and offshore environments: Administrative and political boundaries and offshore sand resources

    USGS Publications Warehouse

    Demopoulos, Amanda W.J.; Foster, Ann M.; Jones, Michal L.; Gualtieri, Daniel J.

    2011-01-01

    The Geospatial Characteristics Geopdf of Florida's Coastal and Offshore Environments is a comprehensive collection of geospatial data describing the political and natural resources of Florida. This interactive map provides spatial information on bathymetry, sand resources, military areas, marine protected areas, cultural resources, locations of submerged cables, and shipping routes. The map should be useful to coastal resource managers and others interested in the administrative and political boundaries of Florida's coastal and offshore region. In particular, as oil and gas explorations continue to expand, the map may be used to explore information regarding sensitive areas and resources in the State of Florida. Users of this geospatial database will find that they have access to synthesized information in a variety of scientific disciplines concerning Florida's coastal zone. This powerful tool provides a one-stop assembly of data that can be tailored to fit the needs of many natural resource managers.

  8. Geologic Storage at the Basin Scale: Region-Based Basin Modeling, Powder River Basin (PRB), NE Wyoming and SE Montana

    NASA Astrophysics Data System (ADS)

    Melick, J. J.; Gardner, M. H.

    2008-12-01

    (second- through fourth-order cycles). Within the small- scale 4th-order sequences (30-150-m thick, 16 total), sedimentation regions, each corresponding to an EOD, are defined by thickness, lithology and core-calibrated well-log patterns. This talk illustrates the workflow by focusing on one of the 16 layers in the basin-scale model. Isopach maps from this sample layer conform to depositional patterns confirmed through definition of five core-calibrated, well-log defined sedimentation regions. Lithology distributions also conform to thickness trends in nearshore deltas, but not in offshore regions, where sand-rich and sheet-like, but thin-bedded sandstones are flanked by mud-rich intervals of equivalent thickness. These maps represent sedimentation patterns confined by basal erosional sequence boundary and basin-wide bentonite, yet containing up to seven high-frequency sequence boundaries. To illustrate over simplification problems in this same layer, a 14000 km2 sample area is 600 km3 and using standard averaging methods, which are considered to be geologic in origin, the CPV is 16 km3. However, averaging increases connectivity with high CPV more uniformly distributed; significantly, the key mud belt region separating nearshore from offshore sandstones is not represented. Region-based modeling of this layer yields 13 km3 (110 Bbl). Furthermore, significant vertical leakage may exist from the 20000 well penetrations and faults and fractures along the western basin margin. This example illustrates the importance of accurately characterizing heterogeneity and distributing CPV using sedimentation regions.

  9. Microseismicity at the North Anatolian Fault in the Sea of Marmara offshore Istanbul, NW Turkey

    USGS Publications Warehouse

    Bulut, Fatih; Bohnhoff, Marco; Ellsworth, William L.; Aktar, Mustafa; Dresen, Georg

    2009-01-01

    The North Anatolian Fault Zone (NAFZ) below the Sea of Marmara forms a “seismic gap” where a major earthquake is expected to occur in the near future. This segment of the fault lies between the 1912 Ganos and 1999 İzmit ruptures and is the only NAFZ segment that has not ruptured since 1766. To monitor the microseismic activity at the main fault branch offshore of Istanbul below the Çınarcık Basin, a permanent seismic array (PIRES) was installed on the two outermost Prince Islands, Yassiada and Sivriada, at a few kilometers distance to the fault. In addition, a temporary network of ocean bottom seismometers was deployed throughout the Çınarcık Basin. Slowness vectors are determined combining waveform cross correlation and P wave polarization. We jointly invert azimuth and traveltime observations for hypocenter determination and apply a bootstrap resampling technique to quantify the location precision. We observe seismicity rates of 20 events per month for M < 2.5 along the basin. The spatial distribution of hypocenters suggests that the two major fault branches bounding the depocenter below the Çınarcık Basin merge to one single master fault below ∼17 km depth. On the basis of a cross-correlation technique we group closely spaced earthquakes and determine composite focal mechanisms implementing recordings of surrounding permanent land stations. Fault plane solutions have a predominant right-lateral strike-slip mechanism, indicating that normal faulting along this part of the NAFZ plays a minor role. Toward the west we observe increasing components of thrust faulting. This supports the model of NW trending, dextral strike-slip motion along the northern and main branch of the NAFZ below the eastern Sea of Marmara.

  10. Divergent/passive margin basins

    SciTech Connect

    Edwards, J.D. ); Santogrossi, P.A. )

    1989-01-01

    This book discusses the detailed geology of the four divergent margin basins and establishes a set of analog scenarios which can be used for future petroleum exploration. The divergent margin basins are the Campos basin of Brazil, the Gabon basin, the Niger delta, and the basins of the northwest shelf of Australia. These four petroleum basins present a wide range of stratigraphic sequences and structural styles that represent the diverse evolution of this large and important class of world petroleum basins.

  11. Quantifying the hurricane catastrophe risk to offshore wind power.

    PubMed

    Rose, Stephen; Jaramillo, Paulina; Small, Mitchell J; Apt, Jay

    2013-12-01

    The U.S. Department of Energy has estimated that over 50 GW of offshore wind power will be required for the United States to generate 20% of its electricity from wind. Developers are actively planning offshore wind farms along the U.S. Atlantic and Gulf coasts and several leases have been signed for offshore sites. These planned projects are in areas that are sometimes struck by hurricanes. We present a method to estimate the catastrophe risk to offshore wind power using simulated hurricanes. Using this method, we estimate the fraction of offshore wind power simultaneously offline and the cumulative damage in a region. In Texas, the most vulnerable region we studied, 10% of offshore wind power could be offline simultaneously because of hurricane damage with a 100-year return period and 6% could be destroyed in any 10-year period. We also estimate the risks to single wind farms in four representative locations; we find the risks are significant but lower than those estimated in previously published results. Much of the hurricane risk to offshore wind turbines can be mitigated by designing turbines for higher maximum wind speeds, ensuring that turbine nacelles can turn quickly to track the wind direction even when grid power is lost, and building in areas with lower risk. PMID:23763387

  12. On the Offshore Advection of Boundary-Layer Structures and the Influence on Offshore Wind Conditions

    NASA Astrophysics Data System (ADS)

    Dörenkämper, Martin; Optis, Michael; Monahan, Adam; Steinfeld, Gerald

    2015-06-01

    The coastal discontinuity imposes strong signals to the atmospheric conditions over the sea that are important for wind-energy potential. Here, we provide a comprehensive investigation of the influence of the land-sea transition on wind conditions in the Baltic Sea using data from an offshore meteorological tower, data from a wind farm, and mesoscale model simulations. Results show a strong induced stable stratification when warm inland air flows over a colder sea. This stratification demonstrates a strong diurnal pattern and is most pronounced in spring when the land-sea temperature difference is greatest. The strength of the induced stratification is proportional to this parameter and inversely proportional to fetch. Extended periods of stable stratification lead to increased influence of inertial oscillations and increased frequency of low-level jets. Furthermore, heterogeneity in land-surface roughness along the coastline is found to produce pronounced horizontal streaks of reduced wind speeds that under stable stratification are advected several tens of kilometres over the sea. The intensity and length of the streaks dampen as atmospheric stability decreases. Increasing sea surface roughness leads to a deformation of these streaks with increasing fetch. Slight changes in wind direction shift the path of these advective streaks, which when passing through an offshore wind farm are found to produce large fluctuations in wind power. Implications of these coastline effects on the accurate modelling and forecasting of offshore wind conditions, as well as damage risk to the turbine, are discussed.

  13. Offshore wind farm electrical cable layout optimization

    NASA Astrophysics Data System (ADS)

    Pillai, A. C.; Chick, J.; Johanning, L.; Khorasanchi, M.; de Laleu, V.

    2015-12-01

    This article explores an automated approach for the efficient placement of substations and the design of an inter-array electrical collection network for an offshore wind farm through the minimization of the cost. To accomplish this, the problem is represented as a number of sub-problems that are solved in series using a combination of heuristic algorithms. The overall problem is first solved by clustering the turbines to generate valid substation positions. From this, a navigational mesh pathfinding algorithm based on Delaunay triangulation is applied to identify valid cable paths, which are then used in a mixed-integer linear programming problem to solve for a constrained capacitated minimum spanning tree considering all realistic constraints. The final tree that is produced represents the solution to the inter-array cable problem. This method is applied to a planned wind farm to illustrate the suitability of the approach and the resulting layout that is generated.

  14. Offshore structure and method of sinking same

    SciTech Connect

    Fern, D. T.

    1985-02-05

    An offshore structure and a method of skinking it to the sea bed. In accordance with one aspect of this invention, the structure is sunk asymmetrically by first sinking a first end portion thereof and then sinking the other end portion. The first end portion is sunk by ballasting it while the other end portion is closed to ballast. The structure is provided with sufficient water plane area while sinking each end portion to maintain stability during the sinking process. In accordance with another aspect of this invention, at least two spaced-apart piles are provided at the end corresponding to the first end portion to absorb the force of impact with the sea bed and to maintain a skirt on the structure out of contact with the sea bed until both ends of the structure have been sunk to the sea bed.

  15. Troll, Haltenpipe showcase offshore pipelay advances

    SciTech Connect

    Blaker, F.; Gjertveit, E.; Breivik, J.

    1996-07-29

    Pipelines installed on the Norwegian continental shelf represent current offshore pipeline installation technology for pipe size (up to 40 in.), water depth (to 540 m) distance between pigging stations (up to 800 km), and complex seabed intervention and landfall construction. Furthermore, the number of deepwater pipelines worldwide has triggered significant advances in the development of pipeline repair. The Troll oil pipeline and Haltenpipe projects faced technical challenges: irregular seabed, conditions requiring highly accurate mapping, careful routing, free-span design, seabed preparation works, and special low-tension lay techniques. The two projects, therefore, have in many ways benefited from each other and been run practically as one large integrated project. The paper describes the design, route preparation, and installation for both pipelines.

  16. Recent advances in offshore pipeline technology

    SciTech Connect

    Bruschi, R.; Vitali, L.

    1994-12-31

    Since the pioneering construction of the TRANSMED pipeline system across the Sicily Channel in the early 80`s, offshore pipeline technology has been progressing towards more and more difficult environments. Now the projects envisaged for the 90`s are venturing far beyond the challenges of the recent past. The scope of this paper is to present the recent research efforts aimed at tackling the main design aspects of the new challenges. Particular attention will be given to the experiences and achievements on the last few years in transmission pipelines across the European Continental Shelf, e.g. in the Central and Southern North Sea and across the Mediterranean Sea. Technologies, tools and purpose developed criteria will be discussed. The performance of current operating pipeline systems will be reviewed and incentives to rationalize design criteria and guidelines will be illustrated.

  17. EARTHQUAKE HAZARDS IN THE OFFSHORE ENVIRONMENT.

    USGS Publications Warehouse

    Page, Robert A.; Basham, Peter W.

    1985-01-01

    This report discusses earthquake effects and potential hazards in the marine environment, describes and illustrates methods for the evaluation of earthquake hazards, and briefly reviews strategies for mitigating hazards. The report is broadly directed toward engineers, scientists, and others engaged in developing offshore resources. The continental shelves have become a major frontier in the search for new petroleum resources. Much of the current exploration is in areas of moderate to high earthquake activity. If the resources in these areas are to be developed economically and safely, potential earthquake hazards must be identified and mitigated both in planning and regulating activities and in designing, constructing, and operating facilities. Geologic earthquake effects that can be hazardous to marine facilities and operations include surface faulting, tectonic uplift and subsidence, seismic shaking, sea-floor failures, turbidity currents, and tsunamis.

  18. Offshore platform structure for artic waters

    SciTech Connect

    Einstabland, T.

    1984-11-27

    An offshore platform structure of the gravity type intended to be installed on a sea bed in artic or corresponding waters. The platform structure comprises a substructure intended to be completely submerged and supported by the sea bed when in installed position, a superstructure extending up from the substructure and up above the sea bed and a deck superstructure supported by the superstructure above the sea level. A fender is provided intended to protect the superstructure against drifting ice and icebergs, the substructure being provided with a preferably horizontal top support slab supporting the fender, the fender being movably arranged on said support slab and comprising a preferably compartmented cylindrical ring-shaped body with a large weight resting preferably freely on the substructure, intended to be arranged apart from the superstructure when in normal position.

  19. Onshore offshore correlation of Pleistocene rhyolitic eruptions from New Zealand: implications for TVZ eruptive history and paleoenvironmental construction

    NASA Astrophysics Data System (ADS)

    Alloway, Brent V.; Pillans, Brad J.; Carter, Lionel; Naish, Tim R.; Westgate, John A.

    2005-08-01

    Taupo Volcanic Zone (TVZ), in the North Island, New Zealand, is arguably the most active Quaternary rhyolitic system in the world. Numerous and widespread rhyolitic tephra layers, sourced from the TVZ, form valuable chronostratigraphic markers in onshore and offshore sedimentary sequences. In deep-sea cores from Ocean Drilling Program (ODP) Leg 181 Sites 1125, 1124, 1123 and 1122, located east of New Zealand, ca 100 tephra beds are recognised post-dating the Plio-Pleistocene boundary at 1.81 Ma. These tephras have been dated by a combination of magnetostratigraphy, orbitally tuned stable-isotope data and isothermal plateau fission track ages. The widespread occurrence of ash offshore to the east of New Zealand is favoured by the small size of New Zealand, the explosivity of the mainly plinian and ignimbritic eruptions and the prevailing westerly wind field. Although some tephras can be directly attributed to known TVZ eruptions, there are many more tephras represented within ODP-cores that have yet to be recognised in near-source on-land sequences. This is due to proximal source area erosion and/or deep burial as well as the adverse effect of vapour phase alteration and devitrification within near-source welded ignimbrites. Despite these difficulties, a number of key deep-sea tephras can be reliably correlated to equivalent-aged tephra exposed in uplifted marine back-arc successions of Wanganui Basin where an excellent chronology has been developed based on magnetostratigraphy, orbitally calibrated sedimentary cycles and isothermal plateau fission track ages on tephra. Significant Pleistocene tephra markers include: the Kawakawa, Omataroa, Rangitawa/Onepuhi, Kaukatea, Kidnappers-B, Potaka, Unit D/Ahuroa, Ongatiti, Rewa, Sub-Rewa, Pakihikura, Ototoka and Table Flat Tephras. Six other tephra layers are correlated between ODP-core sites but have yet to be recognised within onshore records. The identification of Pleistocene TVZ-sourced tephras within the ODP record

  20. Beyond offshoring: assess your company's global potential.

    PubMed

    Farrell, Diana

    2004-12-01

    In the past few years, companies have become aware that they can slash costs by offshoring: moving jobs to lower-wage locations. But this practice is just the tip of the iceberg in terms of how globalization can transform industries, according to research by the McKinsey Global Institute (MGI). The institute's yearlong study suggests that by streamlining their production processes and supply chains globally, rather than just nationally or regionally, companies can lower their costs-as we've seen in the consumer-electronics and PC industries. Companies can save as much as 70% of their total costs through globalization--50% from offshoring, 5% from training and business-task redesign, and 15% from process improvements. But they don't have to stop there. The cost reductions make it possible to lower prices and expand into new markets, attracting whole new classes of customers. To date, however, few businesses have recognized the full scope of performance improvements that globalization makes possible, much less developed sound strategies for capturing those opportunities. In this article, Diana Farrell, director of MGI, offers a step-by-step approach to doing both things. Among her suggestions: Assess where your industry falls along the globalization spectrum, because not all sectors of the economy face the same challenges and opportunities at the same time. Also, pay attention to production, regulatory, and organizational barriers to globalization. If any of these can be changed, size up the cost-saving (and revenue-generating) opportunities that will emerge for your company as a result of those changes. Farrell also defines the five stages of globalization-market entry, product specialization, value chain disaggregation, value chain reengineering, and the creation of new markets-and notes the different levers for cutting costs and creating value that companies can use in each phase. PMID:15605568

  1. Offshore Deformation Front in Miaoli Area

    NASA Astrophysics Data System (ADS)

    Chiang, P.; Gwo-shyn, S.

    2015-12-01

    Taiwan is located at the junction of the Eurasian Plate and the Philippine Sea Plate. It's because arc-continent collision occurs in the western Taiwan, resulting in the orogeny has formed a fold-and-thrust belt, developing a series of thrusts aligned in north-south direction. The thrust faults, locating in the central island, are the oldest and have almost inactive. Westward to the island, the faults become younger, dipping angles are smaller, and motions were stronger. On the west side, the foot of the Taiwan Western Foothill is considered the youngest thrust faults located along west Taiwan. Scholars recognized them as so-called the deformation front, and they also believed that the deformation front is located in between the compressive terrain uplifted area and the extensional subsidence area. Therefore, this front line is on the boundary of two different tectonic zones. This study investigates the trace of the deformation front in Miaoli area. Previous studies suggested that the west side of Miaoli collision zone should be fault-bounded, and is located in the seabed. However, in the geological map, there is no geologic evidence that appears on land and so-called active faults related with this deformation front. In the near coast seafloor, according to the reflection earthquakes data from the Institute of Oceanography of NTU, we can only see the offshore strata have been uplifted, and the data also shows that seabed is only covered by thin layer of sediments. This study indicates that in offshore place within three kilometers, shallow formations show a special layer of slime which was extruded to be corrugated transversely. Accordingly, we believe that this slime layer should be pressurized and filled with muddy water. Such features should be further investigated with other geological and geophysical survey data to check if they belong to the structural product of the deformation front.

  2. 75 FR 2153 - Certificate of Alternative Compliance for the Offshore Supply Vessel C-CHARIOT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-14

    ... SECURITY Coast Guard Certificate of Alternative Compliance for the Offshore Supply Vessel C-CHARIOT AGENCY... Compliance was issued for the offshore supply vessel C-CHARIOT as required by 33 U.S.C. 1605(c) and 33 CFR 81... INFORMATION: Background and Purpose The offshore supply vessel C-CHARIOT will be used for offshore...

  3. Proceedings of the fifth international offshore mechanics and Arctic engineering (OMAE) symposium. Volume 4

    SciTech Connect

    Lunardini, V.J.; Wang, Y.S.; Ayorinde, O.A.; Sodhi, D.V.

    1986-01-01

    This book presents the papers given at a symposium on offshore platforms. Topics considered at the symposium included climates, Arctic regions, hydrate formation, the buckling of heated oil pipelines in frozen ground, icebergs, concretes, air cushion vehicles, mobile offshore drilling units, tanker ships, ice-induced dynamic loads, adfreeze forces on offshore platforms, and multiyear ice floe collision with a massive offshore structure.

  4. 75 FR 4579 - Certificate of Alternative Compliance for the Offshore Supply Vessel INGRID

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-28

    ... SECURITY Coast Guard Certificate of Alternative Compliance for the Offshore Supply Vessel INGRID AGENCY... Compliance was issued for the offshore ] supply vessel INGRID, as required by 33 U.S.C. 1605(c) and 33 CFR 81... INFORMATION: Background and Purpose The offshore supply vessel INGRID will be used for offshore...

  5. NREL Software Aids Offshore Wind Turbine Designs (Fact Sheet)

    SciTech Connect

    Not Available

    2013-10-01

    NREL researchers are supporting offshore wind power development with computer models that allow detailed analyses of both fixed and floating offshore wind turbines. While existing computer-aided engineering (CAE) models can simulate the conditions and stresses that a land-based wind turbine experiences over its lifetime, offshore turbines require the additional considerations of variations in water depth, soil type, and wind and wave severity, which also necessitate the use of a variety of support-structure types. NREL's core wind CAE tool, FAST, models the additional effects of incident waves, sea currents, and the foundation dynamics of the support structures.

  6. Offshore asphaltene and wax deposition: Problems/solutions

    SciTech Connect

    Leontaritis, K.J. |

    1996-05-01

    Many production facilities around the world suffer from either asphaltene or wax deposition. Such problems seriously threaten economic production from many offshore reservoirs due to the high cost of remedial measures. Offshore facilities are especially susceptible to such deposition for a number of reasons. This article presents ideas and methodologies on how to predict, diagnose, prevent, or mitigate problems caused by organic deposition in offshore production facilities. In one facility where these ideas were put to use, despite the debilitating magnitude of the problems, the field has been produced for more than 14 years with minimum environmental impact. Principal conclusions developed are discussed in this paper.

  7. California State Waters Map Series: offshore of San Francisco, California

    USGS Publications Warehouse

    Cochrane, Guy R.; Johnson, Samuel Y.; Dartnell, Peter; Greene, H. Gary; Erdey, Mercedes D.; Golden, Nadine E.; Hartwell, Stephen R.; Endris, Charles A.; Manson, Michael W.; Sliter, Ray W.; Kvitek, Rikk G.; Watt, Janet Tilden; Ross, Stephanie L.; Bruns, Terry R.

    2015-01-01

    Circulation over the continental shelf in the Offshore of San Francisco map area is dominated by the southward-flowing California Current, an eastern limb of the North Pacific Gyre that flows from Oregon to Baja California. At its midpoint offshore of central California, the California Current transports subarctic surface waters southeastward, about 150 to 1,300 km from shore. Seasonal northwesterly winds that are, in part, responsible for the California Current, generate coastal upwelling. Ocean temperatures offshore of central California have increased over the past 50 years, driving an ecosystem shift from the productive subarctic regime towards a depopulated subtropical environment.

  8. Assessment of Offshore Wind System Design, Safety, and Operation Standards

    SciTech Connect

    Sirnivas, S.; Musial, W.; Bailey, B.; Filippelli, M.

    2014-01-01

    This report is a deliverable for a project sponsored by the U.S. Department of Energy (DOE) entitled National Offshore Wind Energy Resource and Design Data Campaign -- Analysis and Collaboration (contract number DE-EE0005372; prime contractor -- AWS Truepower). The project objective is to supplement, facilitate, and enhance ongoing multiagency efforts to develop an integrated national offshore wind energy data network. The results of this initiative are intended to 1) produce a comprehensive definition of relevant met-ocean resource assets and needs and design standards, and 2) provide a basis for recommendations for meeting offshore wind energy industry data and design certification requirements.

  9. Spreading and slope instability at the continental margin offshore Mt Etna, imaged by high-resolution 2D seismic data

    NASA Astrophysics Data System (ADS)

    Gross, Felix; Krastel, Sebastian; Behrmann, Jan-Hinrich; Papenberg, Cord; Geersen, Jacob; Ridente, Domenico; Latino Chiocci, Francesco; Urlaub, Morelia; Bialas, Jörg; Micallef, Aaron

    2015-04-01

    Mount Etna is the largest active volcano in Europe. Its volcano edifice is located on top of continental crust close to the Ionian shore in east Sicily. Instability of the eastern flank of the volcano edifice is well documented onshore. The continental margin is supposed to deform as well. Little, however, is known about the offshore extension of the eastern volcano flank and its adjacent continental margin, which is a serious shortcoming in stability models. In order to better constrain the active tectonics of the continental margin offshore the eastern flank of the volcano, we acquired and processed a new marine high-resolution seismic and hydro-acoustic dataset. The data provide new detailed insights into the heterogeneous geology and tectonics of shallow continental margin structures offshore Mt Etna. In a similiar manner as observed onshore, the submarine realm is characterized by different blocks, which are controlled by local- and regional tectonics. We image a compressional regime at the toe of the continental margin, which is bound to an asymmetric basin system confining the eastward movement of the flank. In addition, we constrain the proposed southern boundary of the moving flank, which is identified as a right lateral oblique fault movement north of Catania Canyon. From our findings, we consider a major coupled volcano edifice instability and continental margin gravitational collapse and spreading to be present at Mt Etna, as we see a clear link between on- and offshore tectonic structures across the entire eastern flank. The new findings will help to evaluate hazards and risks accompanied by Mt Etna's slope- and continental margin instability and will be used as a base for future investigations in this region.

  10. Morphotectonics and sedimentation in convergent margin basins: An example from juxtaposed marginal sea basin and foreland basin, Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Yu, Ho-Shing; Huang, Zehn-Yin

    2009-03-01

    Using reflection seismic profiles and bathymetric mapping this paper reveals the tectonic-sedimentary characteristics of the convergent margins in the northern South China Sea, where it is strongly related to flexure of Chinese rifted margin and overthrust of Taiwan orogen. Convergent margin tectonics of the South China Sea near southern Taiwan is characterized by a progressively northward transition from oceanic subduction along the Manila Trench to the incipient collision zone offshore southern Taiwan where the continental crust of the Eurasian plate subducts beneath the Philippine Sea plate. North of 21°N, dip angles of the Benioff zone increase up to 80° in the incipient collision zone where the Manila Trench becomes shallower, gradually loses its morphological identity and finally merges into the nearly N-S trending Penghu Canyon. Convergent margin tectonics in the initial collision zone in SW Taiwan is manifested by the beginning of flexure of the Chinese margin under the westward migrating overthrust belt of Taiwan, forming two distinct basins. On the passive Chinese margin, the marginal sea basin becomes smaller and is underlain by the South China Sea Slope, while on the active Taiwan margin, a wedge-top basin has formed above the frontal thrust sheets of the Taiwan orogenic wedge. Sediments derived from the Taiwan orogen progressively overlie the strata of the passive Chinese margin, resulting in sediment thickening and basin shallowing from south to north. Sedimentary facies shows that offshore deep-water mud is gradationally overlain by shallow marine sediments. Sediments of the wedge-top basin are being actively deformed into mud diapiric intrusions and a series of west-vergent thrusts and folds with their associated piggy-back basins, resulting in irregular topography of the sea floor with alternating sea ridges and troughs. Pliocene-Quaternary strata of the passive Chinese margin are a little deformed under the westward compression induced by the

  11. Tectonosedimentary evolution of the Crotone basin, Italy: Implications for Calabrian Arc geodynamics

    SciTech Connect

    Smale, J.L. ); Rio, D. ); Thunell, R.C. )

    1990-05-01

    Analysis of outcrop, well, and offshore seismic data has allowed the Neogene tectonosedimentary evolution of an Ionian Sea satellite basin to be outlined. The Crotone basin contains a series of postorogenic sediments deposited since Serravallian time atop a complex nappe system emplaced in the early Miocene. The basin's evolution can be considered predominantly one of distension in a fore-arc setting punctuated by compressional events. The earliest sediments (middle-late Miocene) consist of conglomerates, marls, and evaporites infilling a rapidly subsiding basin. A basin-wide Messinian unconformity and associated intraformational folding mark the close of this sedimentary cycle. Reestablishment of marine conditions in the early Pliocene is documented by sediments which show a distinct color banding and apparent rhythmicity, which may represent the basin margin to lowermost Pliocene marl/limestone rhythmic couplets present in southern Calabria. A bounding unconformity surface of middle Pliocene age (3.0 Ma), which corresponds to a major northwest-southeast compressional event, closes this depositional sequence. The basin depocenter shifted markedly toward the southeast, and both chaotic and strong subparallel reflector seismic facies of wide-ranging thicknesses fill the depositional topography created during this tectonic episode. Basin subsidence decreases dramatically in the late Pliocene and cessates in response to basin margin uplift in the early Pleistocene. The chronostratigraphic hierarchy of these depositional sequences allows them to constrain the deformational history of the basin. In addition, similar depositional hierarchies in adjacent basins (i.e., Paola, Cefalu, and Tyrrhenian Sea) allow them to tie the stratigraphy and evolution of the Crotone basin to the geodynamic evolution of the Calabrian arc system.

  12. Geophysical evaluation of the enigmatic Bedout basement high, offshore northwestern Australia

    NASA Astrophysics Data System (ADS)

    Müller, R. D.; Goncharov, A.; Kritski, A.

    2005-08-01

    The Bedout High in the Roebuck Basin (formerly offshore Canning Basin) on the northwest shelf of Australia is an unusual structure, which has been controversially interpreted as an end-Permian impact structure similar in size to the K-T boundary Chicxulub Crater. We present a geophysical perspective of the associated debate, based on deep seismic reflection, refraction and well data. The basement and crust in the Roebuck Basin display a number of features that distinguish them from other basins along the northwest Australian margin, including major crustal thinning and the presence of a thick layer of interpreted magmatic underplating. The Bedout High consists of two separate highs separated by a Paleozoic fault, and is associated with a Moho uplift of 7-8 km, and is about 40-50 km wide. The normal fault separating the two highs trends NNW-SSE, roughly paralleling a Paleozoic fault system associated with rifting in the Canning Basin and terminating below the interpreted top-Permian reflection. There are no circular, symmetric fault zones bounding the proposed annular trough, and the distinct difference in seismic character normally associated with impact breccias versus layered sediments above are not expressed in deep multichannel seismic data. The end-Permian horizon exhibits little topography, with well-layered units both below and above. The area around the Bedout High stands out as an area of low velocity basement: 5400-5600 m/s compared to 5800-6000 m/s for other nearby basement areas located in a similar depth range, but known complex impact sites are not characterized by a unique seismic basement velocity signature. Both seismic velocity analysis, revealing a thick underplated layer in the lower crust, and thermal modelling based on data from well La Grange-1 and basalts drilled on top of the Bedout High, are consistent with rifting above anomalously hot mantle. The available geophysical and geological data are compatible with an interpretation of the

  13. Hydrocarbon prospects offshore southern West Greenland

    SciTech Connect

    Chalmers, J.A.; Dahl-Jensen, T.; Bate, K.J.; Whittaker, R.C.

    1996-12-31

    Interpretation of regional seismic data acquired in the 1990s together with a re-appraisal of the wells drilled in the 1970s has lead to an appreciation that the southern West Greenland Basin is underexplored and may contain large quantities of hydrocarbons. The regional structure and stratigraphy of the basin has been worked out. An early phase of extension, probably in the Early Cretaceous, was followed by a thermal subsidence phase in the Late Cretaceous during which thick mudstones were deposited. Renewed extension and strike-slip faulting associated with the onset of sea-floor spreading in the Labrador Sea in the Early Tertiary lead to the formation of large structures capable of trapping large quantities of hydrocarbons. Flat spots have been identified in several prospects in the Fylla Structural Complex, which is presently open for licensing, and other large structural traps exist on the Kang{cflx a}miut Ridge and in the Ikermiut area. Stratigraphic traps exist in a large syn-rift fan of mid-Cretaceous age and in Lower Tertiary basin-floor fans. All of these after structures are found in an area with an {open_quotes}open-door{close_quotes} licensing policy.

  14. Hydrocarbon prospects offshore southern West Greenland

    SciTech Connect

    Chalmers, J.A.; Dahl-Jensen, T.; Bate, K.J.; Whittaker, R.C. )

    1996-01-01

    Interpretation of regional seismic data acquired in the 1990s together with a re-appraisal of the wells drilled in the 1970s has lead to an appreciation that the southern West Greenland Basin is underexplored and may contain large quantities of hydrocarbons. The regional structure and stratigraphy of the basin has been worked out. An early phase of extension, probably in the Early Cretaceous, was followed by a thermal subsidence phase in the Late Cretaceous during which thick mudstones were deposited. Renewed extension and strike-slip faulting associated with the onset of sea-floor spreading in the Labrador Sea in the Early Tertiary lead to the formation of large structures capable of trapping large quantities of hydrocarbons. Flat spots have been identified in several prospects in the Fylla Structural Complex, which is presently open for licensing, and other large structural traps exist on the Kang[cflx a]miut Ridge and in the Ikermiut area. Stratigraphic traps exist in a large syn-rift fan of mid-Cretaceous age and in Lower Tertiary basin-floor fans. All of these after structures are found in an area with an [open quotes]open-door[close quotes] licensing policy.

  15. Basin-mountain structures and hydrocarbon exploration potential of west Junggar orogen in China

    NASA Astrophysics Data System (ADS)

    Wu, Xiaozhi; He, Dengfa; Qi, Xuefeng

    2016-04-01

    Situated in northern Xinjiang, China, in NE-SW trend, West Junggar Orogen is adjacent to Altai fold belt on the north with the Ertix Fault as the boundary, North Tianshan fold belt on the south with the Ebinur Lake Strike-slip Fault as the boundary, and the Junggar Basin on the southeast with Zaire-Genghis Khan-Hala'alat fold belt as the boundary. Covering an area of about 10×104 km2 in China, there are medium and small intermontane basins, Burqin-Fuhai, Tacheng, Hefeng and Hoxtolgay, distributing inside the orogen. Tectonically West Junggar Orogen lies in the middle section of the Palaeo-Asian tectonic domain where the Siberia, Kazakhstan and Tarim Plates converge, and is the only orogen trending NE-SW in the Palaeo-Asian tectonic domain. Since the Paleozoic, the orogen experienced pre-Permian plate tectonic evolution and post-Permian intra-plate basin evolution. Complex tectonic evolution and multi-stage structural superimposition not only give rise to long term controversial over the basin basement property but also complex basin-mountain coupling relations, structures and basin superimposition modes. According to analysis of several kinds of geological and geophysical data, the orogen was dominated by compressive folding and thrust napping from the Siberia plate in the north since the Late Paleozoic. Compressive stress weakened from north to south, corresponding to subdued vertical movement and enhanced horizontal movement of crustal surface from north to south, and finally faded in the overthrust-nappe belt at the northwest margin of the Junggar Basin. The variation in compressive stress is consistent with the surface relief of the orogen, which is high in the north and low in the south. There are two kinds of basin-mountain coupling relationships, i.e. high angle thrusting and overthrusting and napping, and two kinds of basin superimposition modes, i.e. inherited and progressive, and migrating and convulsionary modes. West Junggar orogen has rich oil and gas

  16. Use of a mobile diving support vessel, Offshore California

    SciTech Connect

    Carroll, J.P.

    1983-03-01

    The Blue Dolphin is a converted workboat with a one-atmosphere manipulator bell diving system. It provides diving support for Chevron's offshore drilling program. This support includes underwater inspection, repair and salvage.

  17. 78 FR 63233 - National Offshore Safety Advisory Committee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ..., issue of the Federal Register (73 FR 3316). Docket: For access to the docket to read documents or... Equipment in Hazardous Areas on Foreign Flag Mobile Offshore Drilling Units (MODUs); (d) Safety Impact...

  18. Understanding Potential Climate Variability Impacts on the Offshore Energy Industry

    NASA Astrophysics Data System (ADS)

    Stear, J.

    2014-12-01

    Climate variability may have important implications for the offshore energy industry. Scenarios of increased storm activity and changes in sea level could require the retrofit of existing offshore platforms and coastal infrastructure, the decommissioning of facilities for which upgrade or relocation is not economically viable, and the development of new methods and equipment which are removed from or less sensitive to environmental loads. Over the past years the energy industry has been actively involved in collaborative research efforts with government and academia to identify the potential changes in the offshore operating environment, and corresponding risk implications. This presentation will review several of these efforts, and for several of the hypothetical climate variation scenarios, review the potential impacts on and possible mitigations for offshore and coastal energy infrastructure and operations.

  19. OFFSHORE PLATFORM HAZARDOUS WASTE INCINERATION FACILITY: FEASIBILITY STUDY

    EPA Science Inventory

    This report describes a program conducted to evaluate the technical and environmental feasibility of using a proposed offshore platform incineration facility in the destruction of hazardous wastes and for incineration research.

  20. “Open Hatch” Tour of Offshore Wind Buoy

    SciTech Connect

    Zayas, Jose

    2015-09-18

    Wind and Water Power Technologies Office Director, Jose Zayas gives a behind the scenes tour of the AXYS WindSentinel research buoy, which uses high-tech instruments to measure conditions for potential offshore wind energy development.

  1. 12. OFFSHORE VIEW OF PIER, LOOKING EAST, SHOWING LIFEGUARD TOWER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. OFFSHORE VIEW OF PIER, LOOKING EAST, SHOWING LIFEGUARD TOWER AND 2ND TEE (CENTER), REFUGE BAY (RIGHT) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  2. 14. OFFSHORE VIEW OF PIER, LOOKING SOUTHEAST, SHOWING (LEFTRIGHT) PUMPHOUSE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. OFFSHORE VIEW OF PIER, LOOKING SOUTHEAST, SHOWING (LEFT-RIGHT) PUMPHOUSE, TACKLE BOX, RESTROOMS ON 3RD TEE - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  3. Acoustic Velocity Of The Sediments Offshore Southwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Tsai, C.; Liu, C.; Huang, P.

    2004-12-01

    Along the Manila Trench south of 21øXN, deep-sea sediments are being underthrusted beneath the Taiwan accretionary prism which is composed of the Kaoping Slope and Hengchun Ridge. Offshore southwestern Taiwan, foreland sediments and Late Miocene strata of the Tainan Basin are being accreted onto the fold-and thrust belt of the syn-collision accretionary wedge of the Kaoping Slope. The Kaoping Slope consists of thick Neogene to Recent siliciclastics deformed by fold-and-thrust structures and mud diapers. These Pliocene-Quaternary sediments deposited in the Kaoping Shelf and upper slope area are considered to be paleo-channel deposits confined by NNE-SSW trend mud diapiric structure. Seismic P-wave velocities of the sediment deposited in the Kaoping Shelf and Kaoping Slope area are derived from mutichannel seismic reflection data and wide-angle reflection and refraction profiles collected by sonobuoys. Sediment velocity structures constrained from mutichannel seismic reflection data using velocity spectrum analysis method and that derived from sonobuoy data using tau-sum inversion method are compared, and they both provide consistent velocity structures. Seismic velocities were analyzed along the seismic profile from the surface to maximum depths of about 2.0 km below the seafloor. Our model features a sediment layer1 with 400 ms in thickness and a sediment layer2 with 600 ms in thickness. For the shelf sediments, we observe a linear interval velocity trend of V=1.53+1.91T in layer1, and V=1.86+0.87T in layer2, where T is the one way travel time within the layer. For the slop sediment, the trend of V=1.47+1.93T in layer1, and V=1.70+1.55T in layer2. The layer1¡¦s velocities gradients are similar between the shelf (1.91 km/sec2) and the slope(1.93 km/sec2). It means layer1 distributes over the slope and shelf widely. The result of the sediment velocity gradients in this area are in good agreement with that reported for the south Atlantic continental margins.

  4. Seismic Data Analysis to the Converted Wave Acquisition: A Case Study in Offshore Malaysia

    NASA Astrophysics Data System (ADS)

    Latiff, A. H. Abdul; Osman, S. A. A.; Jamaludin, S. N. F.

    2016-07-01

    Many fields in offshore Malaysia suffer from the presence of shallow gas cloud which is one of the major issues in the basin. Seismic images underneath the gas cloud often show poor resolution which makes the geophysical and geological interpretation difficult. This effect can be noticed from the amplitude dimming, loss of high-frequency energy, and phase distortion. In this work, the subsurface will be analyzed through the geophysical interpretation of the converted P-S data. This P-S converted dataset was obtained through ocean bottom cable (OBC) procedure which was conducted at a shallow gas affected field located in Malaysian Basin. The geophysical interpretation process begin by picking the clear faults system and horizons, followed by thorough post-stack seismic data processing procedure. Finally, the attributes analyses were implemented to the seismic section in order to image the unseen faults system. The interpreted seismic sections show significant improvement in the seismic images, particularly through median filter process. Moreover, the combination of structural smoothing and variance procedure had contributed to the correct faults location interpretation.

  5. Frontier seismic geologic techniques and the exploration of the Miocene reefs in offshore Palawan, Philippines

    NASA Astrophysics Data System (ADS)

    Biswas, Buddhadeb

    An 88 km grid of Seislog sections (synthetic sonic log traces) was used to supplement the conventional seismic interpretation to assess the hydrocarbon potential of Lower Miocene reefs of offshore Palawan, Philippines. The porosity distribution in the zone of interest as well as the oil-water contact in and around the Tara and Libro patch reefs were mapped. The structural mapping was also fine tuned, including mapping of faults with small displacements. The paradox of pooling of hydrocarbons is evident in the maximum fill in the front line of traps near the shelf-slope break that are in the lowest structural position. Progressively dwindling amounts of fill in the structurally higher updip basin positions are interpreted to be due to the migration of hydrocarbons from the hydrocarbon kitchen in the Palawan Trough. The front line of traps had the benefit of maximum fill, the traps at the rear only of residual fill that spilled past the frontal traps. Three play types corresponding to the front line of traps, the rear line of traps and the most remote line of traps have been identified. Frontal reefs are considered to have the highest hydrocarbon potential. Diminishing hydrocarbon potential is inferred for closures in the updip direction. A thorough screening of all available seismic control for mapping all the patch reefs that might compensate for their dimensions by their numbers as well as for detecting possible pinnacle reefs in the downdip basin position has been suggested.

  6. Ground Motion Prediction of Subduction Earthquakes using the Onshore-Offshore Ambient Seismic Field

    NASA Astrophysics Data System (ADS)

    Viens, L.; Miyake, H.; Koketsu, K.

    2014-12-01

    Seismic waves produced by earthquakes already caused plenty of damages all around the world and are still a real threat to human beings. To reduce seismic risk associated with future earthquakes, accurate ground motion predictions are required, especially for cities located atop sedimentary basins that can trap and amplify these seismic waves. We focus this study on long-period ground motions produced by subduction earthquakes in Japan which have the potential to damage large-scale structures, such as high-rise buildings, bridges, and oil storage tanks. We extracted the impulse response functions from the ambient seismic field recorded by two stations using one as a virtual source, without any preprocessing. This method allows to recover the reliable phases and relative, rather than absolute, amplitudes. To retrieve corresponding Green's functions, the impulse response amplitudes need to be calibrated using observational records of an earthquake which happened close to the virtual source. We show that Green's functions can be extracted between offshore submarine cable-based sea-bottom seismographic observation systems deployed by JMA located atop subduction zones and on-land NIED/Hi-net stations. In contrast with physics-based simulations, this approach has the great advantage to predict ground motions of moderate earthquakes (Mw ~5) at long-periods in highly populated sedimentary basin without the need of any external information about the velocity structure.

  7. Offshore Wind Balance-of-System Cost Modeling

    SciTech Connect

    Maness, Michael; Stehly, Tyler; Maples, Ben; Mone, Christopher

    2015-09-29

    Offshore wind balance-of-system (BOS) costs contribute up to 70% of installed capital costs. Thus, it is imperative to understand the impact of these costs on project economics as well as potential cost trends for new offshore wind technology developments. As a result, the National Renewable Energy Laboratory (NREL) developed and recently updated a BOS techno-economic model using project cost estimates created from wind energy industry sources.

  8. 2014–2015 Offshore Wind Technologies Market Report

    SciTech Connect

    Smith, Aaron; Stehly, Tyler; Musial, Walter

    2015-09-01

    This report provides data and analysis to assess the status of the U.S. offshore wind industry through June 30, 2015. It builds on the foundation laid by the Navigant Consortium, which produced three market reports between 2012 and 2014. The report summarizes domestic and global market developments, technology trends, and economic data to help U.S. offshore wind industry stakeholders, including policymakers, regulators, developers, financiers, and supply chain participants, to identify barriers and opportunities.

  9. Evaluation of offshore stocking of Lake Trout in Lake Ontario

    USGS Publications Warehouse

    Lantry, B.F.; O'Gorman, R.; Strang, T.G.; Lantry, J.R.; Connerton, M.J.; Schanger, T.

    2011-01-01

    Restoration stocking of hatchery-reared lake trout Salvelinus namaycush has occurred in Lake Ontario since 1973. In U.S. waters, fish stocked through 1990 survived well and built a large adult population. Survival of yearlings stocked from shore declined during 1990–1995, and adult numbers fell during 1998–2005. Offshore stocking of lake trout was initiated in the late 1990s in response to its successful mitigation of predation losses to double-crested cormorants Phalacrocorax auritus and the results of earlier studies that suggested it would enhance survival in some cases. The current study was designed to test the relative effectiveness of three stocking methods at a time when poststocking survival for lake trout was quite low and losses due to fish predators was a suspected factor. The stocking methods tested during 2000–2002 included May offshore, May onshore, and June onshore. Visual observations during nearshore stockings and hydroacoustic observations of offshore stockings indicated that release methods were not a direct cause of fish mortality. Experimental stockings were replicated for 3 years at one site in the southwest and for 2 years at one site in the southeast. Offshore releases used a landing craft to transport hatchery trucks from 3 to 6 km offshore out to 55–60-m-deep water. For the southwest site, offshore stocking significantly enhanced poststocking survival. Among the three methods, survival ratios were 1.74 : 1.00 : 1.02 (May offshore : May onshore : June onshore). Although not statistically significant owing to the small samples, the trends were similar for the southeast site, with survival ratios of 1.67 : 1.00 : 0.72. Consistent trends across years and sites indicated that offshore stocking of yearling lake trout during 2000–2002 provided nearly a twofold enhancement in survival; however, this increase does not appear to be great enough to achieve the 12-fold enhancement necessary to return population abundance to restoration

  10. Conceptual Model of Offshore Wind Environmental Risk Evaluation System

    SciTech Connect

    Anderson, Richard M.; Copping, Andrea E.; Van Cleve, Frances B.; Unwin, Stephen D.; Hamilton, Erin L.

    2010-06-01

    In this report we describe the development of the Environmental Risk Evaluation System (ERES), a risk-informed analytical process for estimating the environmental risks associated with the construction and operation of offshore wind energy generation projects. The development of ERES for offshore wind is closely allied to a concurrent process undertaken to examine environmental effects of marine and hydrokinetic (MHK) energy generation, although specific risk-relevant attributes will differ between the MHK and offshore wind domains. During FY10, a conceptual design of ERES for offshore wind will be developed. The offshore wind ERES mockup described in this report will provide a preview of the functionality of a fully developed risk evaluation system that will use risk assessment techniques to determine priority stressors on aquatic organisms and environments from specific technology aspects, identify key uncertainties underlying high-risk issues, compile a wide-range of data types in an innovative and flexible data organizing scheme, and inform planning and decision processes with a transparent and technically robust decision-support tool. A fully functional version of ERES for offshore wind will be developed in a subsequent phase of the project.

  11. Origin of cratonic basins

    NASA Astrophysics Data System (ADS)

    Dev. Klein, George; Hsui, Albert T.

    1987-12-01

    Tectonic subsidence curves show that the Illinois, Michigan, and Williston basins formed by initial fault-controlled mechanical subsidence during rifting and by subsequent thermal subsidence. Thermal subsidence began around 525 Ma in the Illinois Basin, 520 460 Ma in the Michigan Basin, and 530 500 Ma in the Williston Basin. In the Illinois Basin, a second subsidence episode (middle Mississippian through Early Permian) was caused by flexural foreland subsidence in response to the Alleghanian-Hercynian orogeny. Resurgent Permian rifting in the Illinois Basin is inferred because of intrusion of well-dated Permian alnoites; such intrusive rocks are normally associated with rifting processes. The process of formation of these cratonic basins remains controversial. Past workers have suggested mantle phase changes at the base of the crust, mechanical subsidence in response to isostatically uncompensated excess mass following igneous intrusions, intrusion of mantle plumes into the crust, or regional thermal metamorphic events as causes of basin initiation. Cratonic basins of North America, Europe, Africa, and South America share common ages of formation (around 550 to 500 Ma), histories of sediment accumulation, temporal volume changes of sediment fills, and common dates of interregional unconformities. Their common date of formation suggests initiation of cratonic basins in response to breakup of a late Precambrian super-continent. This supercontinent acted as a heat lens that caused partial melting of the lower crust and upper mantle followed by emplacement of anorogenic granites during extensional tectonics in response to supercontinent breakup. Intrusion of anorogenic granites and other partially melted intrusive rocks weakened continental lithosphere, thus providing a zone of localized regional stretching and permitting formation of cratonic basins almost simultaneously over sites of intrusion of these anorogenic granites and other partially melted intrusive rocks.

  12. Deep structure of the Algerian margin offshore Great Kabylie: Preliminary results of an offshore-onshore seismic profile (SPIRAL campaign)

    NASA Astrophysics Data System (ADS)

    Chafik, Aidi; Abd el Karim, Yelles; Marie-Odile, Beslier; Frauke, Klingelhoefer; Philippe, Schnurle; Rabah, Bracene; Hamou, Djellit; Audrey, Galve; Laure, Schenini; Françoise, Sage; Abdallah, Bounif Mohand ou; Philippe, Charvis

    2013-04-01

    In October-November 2009 the Algerian-French SPIRAL research program (Sismique Profonde et Investigation Régionale du Nord de l'ALgérie) was conducted onboard the R/V Atalante in order to understand the deep structure and tectonic history of the Algerian Margin using multichannel and wide-angle seismic data. An extensive dataset was acquired along five regional transects off Algeria, from Arzew Bay to the west, to Annaba to the east. The profiles range from 80 to 180 km long and around 40 ocean-bottom seismometers were deployed on each profile. All profiles were extended on land up to 125 km by land-stations to better constrain the structure of the margin and the nature of the ocean-continent transition zone. We present the preliminary results from modeling of deep and superficial structures in the central Algerian margin, more precisely in the region of the Great Kabylie where a N-S transect of combined wide-angle data using a set of 40 OBS (ocean bottom seismometer) and 24 on-land seismological stations and reflection seismic data was acquired. The profile with a total length of about 260 km (140 km offshore and approximately 124 km onshore), crosses from the north to south the Algeria-Provence Basin, the central Algerian Margin and onshore the geological unit of the Great Kabylie that represents the Kabylides block and the transitional zone between the internal zone (Kabylides) and the external zone in the central Algeria. The network (OBS and seismological stations), recorded 1031 low frequency air gun shots in order to ensure good penetration in the crust. Travel time tomography of first arrivals time of OBS data has yielded a preliminary model of P wave velocities along the profile. In the oceanic domain, a relatively thin crust of about 5 km thickness was imaged overlying a mantle characterized by seismic velocities of about 8 km/s, and covered by a thin sedimentary layer of about 2 km thickness. For the study of the sedimentary cover near the margin

  13. Interactions of near-coastal and basin-wide features of the Mediterranean Sea in the surface colour and temperature historical record

    SciTech Connect

    Barale, V.; Filippi, P.

    1997-08-01

    Sea surface colour and temperature images, derived from time series of CZCS (1978-1986) and AVHRR (1982-1990) data, have been used to assess the interactions of near-coastal and basin-wide features in the Mediterranean basin. Individual images were processed to apply sensor(s) calibration, to correct for atmospheric contamination, and to estimate chlorophyll-like pigment concentration and surface temperature. Long-term composites show marked differences between western and eastern sub-basins, inshore and offshore domains, northern and southern near-coastal areas. Continental runoff and wind-driven mixing, as well as geomorphology and meteorology of the (northern) basin margins, appear to influence both water dynamics and bio-geo-chemistry. The major sub-basins present a distinct seasonality, superimposed to that of the basin.

  14. The Oquirrh basin revisited

    SciTech Connect

    Erskine, M.C.

    1997-04-01

    The upper Paleozoic succession in the Oquirrh basin in unusually thick, up to 9300 m, and consists mainly of a Pennsylvanian-middle Permian miogeocline of northwestern Utah. Previous workers have suggested a tectonic origin for the Oquirrh basin that is incompatible with the basin location in both time and space. There is no evidence for Pennsylvanian and Lower Permian tectonism in the middle of the miogeocline. Thermal evidence from the Mississippian Mission Canyon shale does no support the implied deep burial of the crustal sag models of basin formation. Stratigraphic and facies evidence indicates a growth fault origin for the basin. Regional isopach maps and facies maps are powerful tools in interpreting depositional environments and in reconstructing fold-and-thrust belts. However, the location of measured sections relative to the location of the growth fault basin. The Charleston-Nebo thrust may have essentially reversed the movement on a growth fault. Thick Oquirrh basin sedimentary rocks may not be required to balance structural sections across this thrust fault. A thin-skinned, extensional growth fault origin for the Oquirrh basin implies that the Cordilleran miogeocline did not participate in the Pennsylvanian north-vergent uplifts of the Ancestral Rocky Mountains.

  15. Data warehouse manages offshore project information

    SciTech Connect

    1998-05-04

    A data warehouse adopted from the POSC/Caesar data model will manage the life-cycle information for the offshore Norway Aasgard project. The Aasgard project comprises the Midgard, Smorbukk, and Smorbukk South fields, which lie in 780--985 ft of water. A semisubmersible production facility will handle gas exports, scheduled to begin in 2000. Statoil estimates that recoverable reserves in the fields are 7.5 tcf of gas and 780 million bbl of oil. Notia software components include: the Intergraph asset and information management (AIM) product; the P/C PDM and P/C RDL models; a data mapping, translation, and import toolkit; the application programming interface (API); and query and browser clients. Intergraph describes AIM, with its object management framework (OMF) from metaphase technology, as the engine upon which Notia is based. The P/C PDM defines the data terminology and structure. A dictionary of standard petrochemical data items, the P/C RDL, defines the various activities, materials, components, and relationships among these items. The API allows users to develop additional functionality, and the toolkit provides resources for translating and mapping data from existing sources into a neutral format so that administrators can prepopulate the data warehouse. A worldwide web browser client allows users to query the data warehouse and display results in a variety of configurable formats, including virtual data sheets.

  16. Integrated fire analysis: Application to offshore cases

    SciTech Connect

    Saubestre, V.; Khalfi, J.P.; Paygnard, J.C.

    1995-12-31

    Evaluating thermal loads from different fire scenarios and then response of the structure to these loads covers several fields. It is also difficult and time consuming to implement. Interfaces are necessary between the heat calculation, transient propagation and structural analysis software packages. Nevertheless, it is necessary to design structures to accommodate heat loads in order to meet safety requirements or functional specification. Elf, along with several operators and organizations, have sponsored a research project on this topic. The project, managed by SINTEF NBL (Norwegian Fire Research Laboratory), has delivered an integrated fire analysis software package which can be used to address design-to-fire-related issues in various contexts. The core modules of the integrated package are robust, well validated analysis tools. This paper describes some benefits (technical or cost related) of using an integrated approach to assess the response of a structure to thermal loads. Three examples are described: consequence of an accidental scenario on the living quarters in an offshore complex, necessity for the reinforcement of a flareboom following a change in process, evaluation of the amount of insulation needed for a topside process primary structure. The paper focuses on the importance for the operator to have a practical tool which can lead to substantial cost saving while reducing the uncertainty linked to safety issues.

  17. Wave loading on offshore structures: A review

    SciTech Connect

    Standing, R.G.

    1984-01-01

    Man has worked close to the sea for many centuries, exploiting its resources and sailing his ships across it. In the process he has experienced, and gained respect for, the enormous forces exerted by sea waves during a violent storm or tsunami. Occasionally a coastal village is devastated; more often ships, harbours, lighthouses and coastal defences are wrecked. The long-term damage may be less dramatic, but no less destructive: sea waves can gradually erode a structure or its foundations, and cause cracking, ultimately leading to failure. Offshore engineering for the oil and gas industry started before World War II, and progress since then has been rapid. Early steel jacket structures were in water depths of 5-15m. By the early 1960s the water depth had reached 100m, and in 1978 the Cognac platform was completed in the Gulf of Mexico at a depth exceeding 300m. Rapidly increasing costs, however, have forced designers to examine radically new methods of production for deeper waters. A range of compliant structures, including tethered buoyant platforms and guyed towers, has been proposed.

  18. Power generation for offshore oil production

    SciTech Connect

    Chellini, R.

    1997-01-01

    French industry has played a major role in supplying surface equipment for the exploitation of the N`Kossa oil field, located in deep waters (150-300 m) some 60 km offshore the Congo Coast. This immense reservoir (7 km long, 4 km wide, 3000 m under the seabed) was discovered in 1984, and production of oil and LPG started recently. Production of crude oil, which will peak 5 million tons in 1998, and LPG, reaching 300000 tons in 1999, is expected to continue for a period of 30 years. The NKP floating barge used for production is considered a world first in many aspects. It was designed by CTIP Geoproduction (TPG) for the operator, ELF Congo, and was constructed in Marseilles. The barge, which features a prestressed concrete hull, has a bearing capacity of 330000 tons. It is 220 long and 46 m wide, providing a deck area of one hectare. All production facilities as well as living quarters for 160 people are housed on the barge which, for construction purposes, was subdivided into six modules. This paper describes the design of the power generation module. 3 figs.

  19. Surface ozone in the Lake Tahoe Basin

    NASA Astrophysics Data System (ADS)

    Burley, Joel D.; Theiss, Sandra; Bytnerowicz, Andrzej; Gertler, Alan; Schilling, Susan; Zielinska, Barbara

    2015-05-01

    Surface ozone (O3) concentrations were measured in and around the Lake Tahoe Basin using both active monitors (2010) and passive samplers (2002, 2010). The 2010 data from active monitors indicate average summertime diurnal maxima of approximately 50-55 ppb. Some site-to-site variability is observed within the Basin during the well-mixed hours of 10:00 to 17:00 PST, but large differences between different sites are observed in the late evening and pre-dawn hours. The observed trends correlate most strongly with elevation, topography, and surface vegetation. High elevation sites with steeply sloped topography and drier ground cover experience elevated O3 concentrations throughout the night because they maintain good access to downward mixing of O3-rich air from aloft with smaller losses due to dry deposition. Low elevation sites with flat topography and more dense surface vegetation experience low O3 concentrations in the pre-dawn hours because of greatly reduced downward mixing coupled with enhanced O3 removal via efficient dry deposition. Additionally, very high average O3 concentrations were measured with passive samplers in the middle of the Lake in 2010. This latter result likely reflects diminished dry deposition to the surface of the Lake. High elevation Tahoe Basin sites with exposure to nocturnal O3-rich air from aloft experience daily maxima of 8-h average O3 concentrations that are frequently higher than concurrent maxima from the polluted upwind comparison sites of Sacramento, Folsom, and Placerville. Wind rose analyses of archived NAM 12 km meteorological data for the summer of 2010 suggest that some of the sampling sites situated near the shoreline may have experienced on-shore "lake breezes" during daytime hours and/or off-shore "land breezes" during the night. Back-trajectory analysis with the HYSPLIT model suggests that much of the ozone measured at Lake Tahoe results from the transport of "polluted background" air into the Basin from upwind

  20. Thermo-tectonic history of Taranaki Basin (New Zealand) using Apatite Fission Track Analysis (AFTA)

    SciTech Connect

    Kamp, P.J.J.; Hegarty, K.A.; Green, P.F.

    1988-01-01

    The Taranaki basin, which extends offshore between the north and south island of New Zealand, contains several large gas fields (e.g., Maui field) and smaller oil fields. The Taranaki basin is New Zealand's only productive hydrocarbon basin. The basin trends north-south, is asymmetrical in cross section, and is faulted with up to 7 km of displacement along parts of its eastern margin. Preliminary results from Apatite Fission Track Analysis (AFTA) reveal the timing and magnitude of basin inversion. Four well cross sections from the southern part of the basin have been used. Initially, basin tectonics and sedimentation were associated with extension and the formation of half-grabens that began in the Late Cretaceous with the breakup of Gondwana. However, most of the observed subsidence and sedimentation resulted from mid-Cenozoic rifting throughout western New Zealand. Following the formation of the modern Australia-Pacific plate boundary during the early Miocene, the southern part of the basin, which lies 60 km from the Alpine fault in places, was partially inverted. AFTA parameters (apparent age and length) downhold at the Fresne-1 well show a distinct break in slope at 1,100 m depth (currently at 30/sup 0/C) where the apparent age is 15 Ma for the Late Cretaceous Parkawau Coal Measures. The data indicate that basin inversion began about 15 Ma and was accompanied by the removal of 2-3 km of section. Sedimentation began again in the Taranaki basin during the mid-Pliocene. The source of the gas and gas condensate in the basin is probably the Eocene coal measures. The maturation history of these beds and the overlying reservoirs was modeled using the constraints from AFTA data. Discrepancies exist between estimates of maximum paleotemperature from AFTA results and from vitrinite reflectance.

  1. K Basin safety analysis

    SciTech Connect

    Porten, D.R.; Crowe, R.D.

    1994-12-16

    The purpose of this accident safety analysis is to document in detail, analyses whose results were reported in summary form in the K Basins Safety Analysis Report WHC-SD-SNF-SAR-001. The safety analysis addressed the potential for release of radioactive and non-radioactive hazardous material located in the K Basins and their supporting facilities. The safety analysis covers the hazards associated with normal K Basin fuel storage and handling operations, fuel encapsulation, sludge encapsulation, and canister clean-up and disposal. After a review of the Criticality Safety Evaluation of the K Basin activities, the following postulated events were evaluated: Crane failure and casks dropped into loadout pit; Design basis earthquake; Hypothetical loss of basin water accident analysis; Combustion of uranium fuel following dryout; Crane failure and cask dropped onto floor of transfer area; Spent ion exchange shipment for burial; Hydrogen deflagration in ion exchange modules and filters; Release of Chlorine; Power availability and reliability; and Ashfall.

  2. U.S. Offshore Wind Manufacturing and Supply Chain Development

    SciTech Connect

    Hamilton, Bruce Duncan

    2013-02-22

    The objective of the report is to provide an assessment of the domestic supply chain and manufacturing infrastructure supporting the U.S. offshore wind market. The report provides baseline information and develops a strategy for future development of the supply chain required to support projected offshore wind deployment levels. A brief description of each of the key chapters includes: » Chapter 1: Offshore Wind Plant Costs and Anticipated Technology Advancements. Determines the cost breakdown of offshore wind plants and identifies technical trends and anticipated advancements in offshore wind manufacturing and construction. » Chapter 2: Potential Supply Chain Requirements and Opportunities. Provides an organized, analytical approach to identifying and bounding the uncertainties associated with a future U.S. offshore wind market. It projects potential component-level supply chain needs under three demand scenarios and identifies key supply chain challenges and opportunities facing the future U.S. market as well as current suppliers of the nation’s land-based wind market. » Chapter 3: Strategy for Future Development. Evaluates the gap or competitive advantage of adding manufacturing capacity in the U.S. vs. overseas, and evaluates examples of policies that have been successful . » Chapter 4: Pathways for Market Entry. Identifies technical and business pathways for market entry by potential suppliers of large-scale offshore turbine components and technical services. The report is intended for use by the following industry stakeholder groups: (a) Industry participants who seek baseline cost and supplier information for key component segments and the overall U.S. offshore wind market (Chapters 1 and 2). The component-level requirements and opportunities presented in Section 2.3 will be particularly useful in identifying market sizes, competition, and risks for the various component segments. (b) Federal, state, and local policymakers and economic development

  3. Petroleum geology of the major producing basins of Algeria

    SciTech Connect

    Attar, A.; Chaouch, A.

    1988-08-01

    The South Atlas flexure divides Algeria into two contrasting geologic provinces: (1) the Saharan Atlas and offshore region in the north, both of which are part of the Mediterranean basin, and (2) the Saharan platform on the south, part of the North African craton. The limits of the various sedimentary basins on the Saharan platform are tied to late Paleozoic (Hercynian) crustal reactivation. Comparable structurally controlled basins in northern Algeria are the products of Mesozoic-Recent tectonism. The spatial and temporal distribution of hydrocarbons in the Algerian Sahara can be understood in terms of the geologic evolution of the region. Analysis of areas of proven hydrocarbon reserves permits the following generalizations. (1) There is a concentration of oil and gas fields northeast of a northwest-southeast-trending line connecting Hassi R'Mel with In Amenas. Production is also established in the Sbaa basin and in northern Algeria, where recent discoveries have been made in, respectively, upper Paleozoic and Mesozoic reservoirs. (2) Hydrocarbon are present throughout the entire sedimentary column, but major production currently is restricted to the lower Paleozoic (Cambrian-Ordovician and Lower Devonian) and Triassic reservoirs.

  4. A sediment budget for the Transkei Basin, Southwest Indian Ocean

    NASA Astrophysics Data System (ADS)

    Uenzelmann-Neben, Gabriele; Clift, Peter D.

    2015-12-01

    Deep sea sediment budgets can be used to constrain erosion rates in the neighboring continents from which the material was derived. Here we construct a sediment budget for the Transkei Basin, offshore South Africa using an existing seismic reflection survey and dated by correlation of seismic attributes to dated sections in nearby basins. Backstripping of the sections reveals that sediment accumulation rates fell from 110 to 11 Ma, with a possible period of rapid accumulation from 36 to 34 Ma that may be driven by strengthening of the Antarctic Bottom Water (AABW). The long term trend is linked to erosional degradation of the onshore continental escarpment, formed as a consequence of continental break-up. No change is noted at 30 Ma, coincident with proposed uplift of southern Africa driven by plume activity. The basin shows a significant increase in sediment accumulation after 11 Ma, which we interpret to reflect strengthening and rerouting of the AABW from the south into Transkei Basin, as a far field effect of the start of closure of the Indonesian Throughflow.

  5. Geology of the Eel River basin and adjacent region: Implications for late Cenozoic tectonics of the southern Cascadia subduction zone and Mendocino triple junction

    SciTech Connect

    Clarke, S.H. Jr. )

    1992-02-01

    Two upper Cenozoic depositional sequences of principally marine strata about 4,000 m thick overlie accreted basement terranes of the Central and Coastal belts of the Franciscan Complex in the onshore-offshore Eel River basin of northwestern California. The older depositional sequence is early to middle Miocene in age and represents slope basin and slope-blanket deposition, whereas the younger sequence, later Miocene to middle Pleistocene in age, consists largely of forearc basin deposits. Youthful tectonic activity related to Gorda-North American plate convergence indicates an active Cascadia subduction zone and strong partial coupling between these plates. Structures of the northeastern margin of the Eel River basin are principally north-northwest-trending, east-northeast-dipping thrust and reverse faults that form imbricate thrust fans. The Coastal belt fault, the early Tertiary accretionary suture between the Franciscan Central and Coastal belts, can be traced from Arcata Bay northward offshore to the southern Oregon border. It is tentatively extended farther northward based on aeromagnetic data to an offshore position west of Cape Blanco. Thereafter, it may coincide with the offshore Fulmar fault. The Cascadia subduction zone (CSZ) does not join the Mendocino transform fault at the commonly depicted offshore location of the Mendocino triple junction (MTJ). Instead, the CSZ extends southeastward around the southern Eel River basin and shoreward along Mendocino Canyon to join the Petrolia shear zone. Similarly, the Mendocino fault may extend shoreward via Mattole Canyon and join the Cooskie shear zone. These two shear zones intersect onshore north of the King Range, and the area of their intersection is the probable location of the MTJ.

  6. Crustal structure and rift tectonics across the Cauvery-Palar basin, Eastern Continental Margin of India based on seismic and potential field modelling

    NASA Astrophysics Data System (ADS)

    Twinkle, D.; Rao, G. Srinivasa; Radhakrishna, M.; Murthy, K. S. R.

    2016-03-01

    The Cauvery-Palar basin is a major peri-cratonic rift basin located along the Eastern Continental Margin of India (ECMI) that had formed during the rift-drift events associated with the breakup of eastern Gondwanaland (mainly India-Sri Lanka-East Antarctica). In the present study, we carry out an integrated analysis of the potential field data across the basin to understand the crustal structure and the associated rift tectonics. The composite-magnetic anomaly map of the basin clearly shows the onshore-to-offshore structural continuity, and presence of several high-low trends related to either intrusive rocks or the faults. The Curie depth estimated from the spectral analysis of offshore magnetic anomaly data gave rise to 23 km in the offshore Cauvery-Palar basin. The 2D gravity and magnetic crustal models indicate several crustal blocks separated by major structures or faults, and the rift-related volcanic intrusive rocks that characterize the basin. The crustal models further reveal that the crust below southeast Indian shield margin is ˜36 km thick and thins down to as much as 13-16 km in the Ocean Continent Transition (OCT) region and increases to around 19-21 km towards deep oceanic areas of the basin. The faulted Moho geometry with maximum stretching in the Cauvery basin indicates shearing or low angle rifting at the time of breakup between India-Sri Lanka and the East Antarctica. However, the additional stretching observed in the Cauvery basin region could be ascribed to the subsequent rifting of Sri Lanka from India. The abnormal thinning of crust at the OCT is interpreted as the probable zone of emplaced Proto-Oceanic Crust (POC) rocks during the breakup. The derived crustal structure along with other geophysical data further reiterates sheared nature of the southern part of the ECMI.

  7. Ferry Lake, Rodessa, and Punta Gorda Anhydrite bed correlation, lower cretaceous, offshore eastern Gulf of Mexico

    SciTech Connect

    Petty, A.J.

    1995-10-01

    The Lower Cretaceous Ferry Lake and Punta Gorda Anhydrite have been used as marker beds throughout Gulf of Mexico, and divided into nine individual anhydrite beds traceable from southern Mississippi to southern Florida. The underlying Rodessa Formation has an equally well-developed anhydrite section in the offshore Eastern Gulf of Mexico and is divided into twelve basinwide anhydrite bed groupings. The anhydrites of Ferry Lake and Rodessa Formation are traceable to the anhydrites of the Punta Gorda and Lehigh Acres Formations of South Florida. Anhydrite beds appear to thicken in the central part of the trend interfingering with carbonates of the Lower Cretaceous shelf edge reef. Paleontologic data indicate that depositional water depths of the interbedded carbonates range from sea level to 100 meters. Carbonates and anhydrites may be deposited simultaneously with carbonate patchreefs developing on crests of paleo anhydrites may be deposited simultaneously with carbonate patchreefs developing on crests of paleo highs with evaporites precipitating out of a hyper-saline solution on the flanks. Areas where poor anhydrite bed development occurs may indicate areas of patch reefs and, therefore, the best potential for hydrocarbon reservoirs. Individual anhydrite beds have been correlated and color-coded on photocopies of compensated neutron density logs to determine their geographic distribution. Prepared cross sections show some beds to be areawide while others are more restricted. Isopach maps show the configuration of the basin in which these beds were deposited with the basin`s long isopach axis parallel to the reef trend. Anhydrite deposition occurred with evaporation of restricted highstand waters behind reefs that rimmed the shelf edge.

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

    SciTech Connect

    Turner, N.L. )

    1990-06-01

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

  9. Structure and sediment budget of Yinggehai-Song Hong basin, South China Sea: Implications for Cenozoic tectonics and river basin reorganization in Southeast Asia

    NASA Astrophysics Data System (ADS)

    Lei, Chao; Ren, Jianye; Sternai, Pietro; Fox, Matthew; Willett, Sean; Xie, Xinong; Clift, Peter D.; Liao, Jihua; Wang, Zhengfeng

    2015-08-01

    The temporal link between offshore stratigraphy and onshore topography is of key importance for understanding the long-term surface evolution of continental margins. Here we present a grid of regional, high-quality reflection seismic and well data to characterize the basin structure. We identify fast subsidence of the basin basement and a lack of brittle faulting of the offshore Red River fault in the Yinggehai-Song Hong basin since 5.5 Ma, despite dextral strike-slip movement on the onshore Red River fault. We calculate the upper-crustal, whole-crustal, and whole-lithospheric stretching factors for the Yinggehai-Song Hong basin, which show that the overall extension observed in the upper crust is substantially less than that observed for the whole crust or whole lithosphere. We suggest that fast basement subsidence after 5.5 Ma may arise from crustal to lithospheric stretching by the regional dynamic lower crustal/mantle flow originated by collision between India-Eurasia and Indian oceanic subduction below the Eurasian margin. In addition, we present a basin wide sediment budget in the Yinggehai-Song Hong basin to reconstruct the sedimentary flux from the Red River drainage constrained by high-resolution age and seismic stratigraphic data. The sediment accumulation rates show a sharp increase at 5.5 Ma, which suggests enhanced onshore erosion rates despite a slowing of tectonic processes. This high sediment supply filled the accommodation space produced by the fast subsidence since 5.5 Ma. Our data further highlight two prominent sharp decreases of the sediment accumulation at 23.3 Ma and 12.5 Ma, which could reflect a loss of drainage area following headwater capture from the Paleo-Red River. However, the low accumulation rate at 12.5 Ma also correlates with drier and therefore less erosive climatic conditions.

  10. High energy environment offshore deposits in the western Gulf of Corinth, Greece

    NASA Astrophysics Data System (ADS)

    Beckers, Arnaud; Mortier, Clément; Beck, Christian; Hubert-Ferrari, Aurélia; Reyss, Jean-Louis; Tripsanas, Efthymios; Sakellariou, Dimitris; De Batist, Marc; De Rycker, Koen; Bascou, Pascale; Strivay, David

    2013-04-01

    Related to the Gulf of Corinth rifting, five earthquakes of magnitude greater than 5.8 occurred in the last 35 years. Consequently, the question of earthquake hazard is particularly relevant. A partial historical seismic catalogue exists but is not enough for a reliable estimate of recurrence times of co-seismic activity of the normal (or normal/strike slip) faults bounding the Gulf. Onland paleoseismological data are scarce and offshore data were absent before the present study. In 2011, We investigated recent sediments bounding two well-defined major seismogenic faults: Aegion and Trizonia F.. We retrieved 7 gravity cores from 50 to 70 cm long in two distinct sites. On the Aigion Site located on the Southern Shelf of the Gulf (between 40 and 50 m deep), we collected four cores in a transect across the Aigion Fault. On the Trizonia Site located in a 180m deep Sub-Basin on the northern part of the Gulf, three cores are taken in transect from the northern edge to the center of the Sub-Basin, itself lying on the footwall of the Trizonia Fault .Chronology is based on 137Cs (Atmospheric Nuclear Experiments) and 210Pb decay. Concentrations are measured on one core from each site in order to propose an age model. Considering sedimentation rates estimates in these areas, cores could record between 300 and 650 years of sedimentary archives. We performed granulometry, magnetic susceptibility, loss on ignition (105°C, 550°C, 950°C) and geochemical (X-Ray Fluorescence) measurements on cores from each site. We sought to identify layers potentially attributed to earthquake-related processes like liquefaction and tsunamis for the Aigion Shelf or mass transport and turbidity currents for the Trizonia Sub-Basin. In Aegion, three coarser layers have been identified at identical depth in three cores across the scarp. They all are composed of terrigenous grains and sea shell fragments. Geochemical analysis did not show any typical signature. The high number of sea shell fragments

  11. Sensitivity Analysis of Offshore Wind Cost of Energy (Poster)

    SciTech Connect

    Dykes, K.; Ning, A.; Graf, P.; Scott, G.; Damiami, R.; Hand, M.; Meadows, R.; Musial, W.; Moriarty, P.; Veers, P.

    2012-10-01

    No matter the source, offshore wind energy plant cost estimates are significantly higher than for land-based projects. For instance, a National Renewable Energy Laboratory (NREL) review on the 2010 cost of wind energy found baseline cost estimates for onshore wind energy systems to be 71 dollars per megawatt-hour ($/MWh), versus 225 $/MWh for offshore systems. There are many ways that innovation can be used to reduce the high costs of offshore wind energy. However, the use of such innovation impacts the cost of energy because of the highly coupled nature of the system. For example, the deployment of multimegawatt turbines can reduce the number of turbines, thereby reducing the operation and maintenance (O&M) costs associated with vessel acquisition and use. On the other hand, larger turbines may require more specialized vessels and infrastructure to perform the same operations, which could result in higher costs. To better understand the full impact of a design decision on offshore wind energy system performance and cost, a system analysis approach is needed. In 2011-2012, NREL began development of a wind energy systems engineering software tool to support offshore wind energy system analysis. The tool combines engineering and cost models to represent an entire offshore wind energy plant and to perform system cost sensitivity analysis and optimization. Initial results were collected by applying the tool to conduct a sensitivity analysis on a baseline offshore wind energy system using 5-MW and 6-MW NREL reference turbines. Results included information on rotor diameter, hub height, power rating, and maximum allowable tip speeds.

  12. Paleogeography of the Mesozoic Jeanne d'Arc basin, Grand Banks, Newfoundland, Canada

    SciTech Connect

    Mccracken, J.N. )

    1991-03-01

    The major stratigraphic sequences of the Jeanne d'Arc basin, Grand Banks, offshore Newfoundland, Canada, and their relationship to the tectonic events involved in the opening of the North Atlantic are summarized. This basin has been a major exploration area for Mobil and industry since 1971. This activity has resulted in the shooting of over 300,000 km of reflection seismic lines and the drilling of 65 wells. Fifteen discoveries have been found in the basin to date by industry. The Hibernia project is underway with production planned in 1996. Government basin analysis estimates for total ultimate recoverable reserves in the Jeanne d'Arc basin range from 3.3 to 10 billion bbl of oil equivalent. The major stratigraphic events from the Late Jurassic to the Early Eocene within the Jeanne d'Arc basin are illustrated by six isometric paleogeographic reconstructions. These geological sequences are then related on the stratigraphic column to the tectonics and coastal onlap curves. The major controls on Jeanne d'Arc basin deposition were the tectonics created as a result of the northward propagation of the rifting of the Atlantic Ocean and its effect locally on the broad arch to the south called the Avalon Uplift. This provided the major clastic source throughout the Mesozoic. Changes in relative sea level then overprinted these tectonic events.

  13. Mesozoic history of the Fairway-Aotea Basin: Implications for the early stages of Gondwana fragmentation

    NASA Astrophysics Data System (ADS)

    Collot, J.; Herzer, R.; Lafoy, Y.; GéLi, L.

    2009-12-01

    The Fairway Ridge is a buried continental structure that separates the Fairway Basin from the New Caledonia Basin. The proposed Cretaceous age of the Fairway Basin has remained highly hypothetical to date. Deep offshore petroleum exploration wells revealed well-dated Mesozoic carbonaceous sedimentary rocks in the Taranaki Basin at the southern end of the Aotea Basin. In this paper we use geophysical data to confirm the continuity of the 2000 km long Fairway-Aotea Basin connecting New Caledonia to New Zealand and prove its early Late Cretaceous age. Analysis of seismic reflection profiles together with newly compiled gravity and magnetic maps reveals Late Cretaceous NE-SW trending lineaments projecting northeastward from major Tasman Sea fracture zones and the Bellona Trough, which demonstrate that the opening of the Fairway-Aotea Basin predates the opening of the Tasman Sea. This result combined with observations of the Mesozoic regional geology suggests that the Lord Howe, Fairway, and Norfolk ridges are part of a remnant late Early Cretaceous continental arc, which was fragmented into three pieces by the late Early to early Late Cretaceous. This event might be contemporaneous with a plate motion change between the Gondwana and Pacific plates and/or the arrival of the Hikurangi plateau in the subduction zone around 105 Ma, which caused the cessation of subduction along this plate boundary. We interpret either of those two events as being possible trigger events for the post-Early Cretaceous fragmentation of the eastern Gondwana margin in a slab retreat process.

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

    NASA Astrophysics Data System (ADS)

    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

    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

  15. Petroleum geology and resources of the West Siberian Basin, Russia

    USGS Publications Warehouse

    Ulmishek, Gregory F.

    2003-01-01

    The West Siberian basin is the largest petroleum basin in the world covering an area of about 2.2 million km2. The basin occupies a swampy plain between the Ural Mountains and the Yenisey River. On the north, the basin extends offshore into the southern Kara Sea. On the west, north, and east, the basin is surrounded by the Ural, Yenisey Ridge, and Turukhan-Igarka foldbelts that experienced major deformations during the Hercynian tectonic event and the Novaya Zemlya foldbelt that was deformed in early Cimmerian (Triassic) time. On the south, the folded Caledonian structures of the Central Kazakhstan and Altay-Sayan regions dip northward beneath the basin?s sedimentary cover. The basin is a relatively undeformed Mesozoic sag that overlies the Hercynian accreted terrane and the Early Triassic rift system. The basement is composed of foldbelts that were deformed in Late Carboniferous?Permian time during collision of the Siberian and Kazakhstan continents with the Russian craton. The basement also includes several microcontinental blocks with a relatively undeformed Paleozoic sedimentary sequence. The sedimentary succession of the basin is composed of Middle Triassic through Tertiary clastic rocks. The lower part of this succession is present only in the northern part of the basin; southward, progressively younger strata onlap the basement, so that in the southern areas the basement is overlain by Toarcian and younger rocks. The important stage in tectono-stratigraphic development of the basin was formation of a deep-water sea in Volgian?early Berriasian time. The sea covered more than one million km2 in the central basin area. Highly organic-rich siliceous shales of the Bazhenov Formation were deposited during this time in anoxic conditions on the sea bottom. Rocks of this formation have generated more than 80 percent of West Siberian oil reserves and probably a substantial part of its gas reserves. The deep-water basin was filled by prograding clastic clinoforms

  16. Reserves in western basins

    SciTech Connect

    Caldwell, R.H.; Cotton, B.W.

    1995-04-01

    The objective of this project is to investigate the reserves potential of tight gas reservoirs in three Rocky Mountain basins: the Greater Green River (GGRB), Uinta and Piceance basins. The basins contain vast gas resources that have been estimated in the thousands of Tcf hosted in low permeability clastic reservoirs. This study documents the productive characteristics of these tight reservoirs, requantifies gas in place resources, and characterizes the reserves potential of each basin. The purpose of this work is to promote understanding of the resource and to encourage its exploitation by private industry. At this point in time, the GGRB work has been completed and a final report published. Work is well underway in the Uinta and Piceance basins which are being handled concurrently, with reports on these basins being scheduled for the middle of this year. Since the GGRB portion of the project has been completed, this presentation win focus upon that basin. A key conclusion of this study was the subdivision of the resource, based upon economic and technological considerations, into groupings that have distinct properties with regard to potential for future producibility, economics and risk profile.

  17. Longitudinal evolution of the tectonic style along the Cyprus Arc, northern margin of the Levant and Herodotus Basins

    NASA Astrophysics Data System (ADS)

    Symeou, Vasilis; Homberg, Catherine; Nader, Fadi; Darnault, Romain; Lecomte, Jean-Claude

    2016-04-01

    The Levant Basin is bounded to the north by the Cyprus Arc zone which was created by the northward movement of the African plate with respect to the Eurasian plate since Late Cretaceous time. The westward movement of the Anatolian micro-plate since Late Miocene created an additional strike-slip component along the plate boundary. The main objective of this contribution is to portray the structural architecture and features offshore Cyprus by analyzing available 2D seismic data in order to investigate the transition in tectonic style from compression to strike slip along the Cyprus Arc zone. We identified three different crustal domains offshore Cyprus that are from east to west: the eastern domain which belongs to the Levant Basin, the South-central domain which includes the Eratosthenes Seamount, and the South-West domain of Cyprus which corresponds to the Herodotus Basin. In the Levant Basin, the sequences identified are from Base Pliocene extending until the Senonian unconformity. The same sequences in the Cyprus Basin are offset and less thick due to the movement of the Latakia Ridge, which is identified as a steeply dipping sub-vertical fault on our data. In the central domain, the horizons identified on the Eratosthenes Seamount indicate that the Seamount is a Mesozoic carbonate platform covered by thin Miocene/Plio-Pleistocene sediments. A subdivision of the sedimentary sequence in the Herodotus Basin is proposed down to the Paleocene-Eocene basis. A major change in the structural style of the deformation is observed form west to east. Whereas the Levant Basin is almost undeformed south of the Latakia Ridge, several structures were mapped in the central domain, like flexural basin, pop-up structures and back-thrusts. South-verging thrusts were also, identified in the Cyprus Basin. All these structures show a Pliocene activity. Our data suggest that the heterogeneity of the crustal structure played a major role in the longitudinal evolution of the plate

  18. Future for Offshore Wind Energy in the United States: Preprint

    SciTech Connect

    Musial, W.; Butterfield, S.

    2004-06-01

    Until recently, the offshore wind energy potential in the United States was ignored because vast onshore wind resources have the potential to fulfill the electrical energy needs for the entire country. However, the challenge of transmitting the electricity to the large load centers may limit wind grid penetration for land-based turbines. Offshore wind turbines can generate power much closer to higher value coastal load centers. Reduced transmission constraints, steadier and more energetic winds, and recent European success, have made offshore wind energy more attractive for the United States. However, U.S. waters are generally deeper than those on the European coast, and will require new technology. This paper presents an overview of U.S. coastal resources, explores promising deepwater wind technology, and predicts long-term cost-of-energy (COE) trends. COE estimates are based on generic 5-MW wind turbines in a hypothetical 500-MW wind power plant. Technology improvements and volume production are expected to lower costs to meet the U.S. Department of Energy target range of $0.06/kWh for deployment of deepwater offshore wind turbines by 2015, and $0.05/kWh by 2012 for shallow water. Offshore wind systems can diversify the U.S. electric energy supply and provide a new market for wind energy that is complementary to onshore development.

  19. Shift work at a modern offshore drilling rig.

    PubMed

    Rodrigues, V F; Fischer, F M; Brito, M J

    2001-12-01

    The oil and gas exploration and production offshore units are classified as hazardous installations. Work in these facilities is complex, confined and associated with a wide range of risks. The continuous operation is secured by various shift work patterns. The objective of this study was to evaluate how offshore drilling workers perceived shift work at high seas and its impacts on their life and working conditions. The main features of the studied offshore shift work schedules are: long time on board (14 to 28 days), extended shifts (12 hours or more per day), slow rotation (7 to 14 days in the same shift), long sequence of days on the night shift (7 to 14 days in a row) and the extra-long extended journey (18 hours) on shift change and landing days. Interviews revealed a wide range of stressors caused by the offshore shift work, as well as difficulties to conciliate work with family life. It was observed that changes of the family model, leading to role conflicts and social isolation, work in a hazardous environment, perceiving poor sleep when working at night shifts and the imbalance between the expected and actual rewards are the major stressors for the offshore drilling workers. PMID:14564877

  20. Data and Modeling Needs for Offshore Wind Energy

    NASA Astrophysics Data System (ADS)

    Green, D. S.; Bailey, B.; AMS Offshore Energy APT

    2011-12-01

    The offshore wind energy community is identifying needs and strategies for expansion of meteorological and oceanographic (met-ocean) data required to support studies of the U.S. wind resource and conditions relevant to wind farm development and operation in offshore locations. The American Meteorological Society (AMS) in collaboration with many other organizations has identified Offshore Wind Energy as an Annual Partnership Topic and established a Committee that is bringing stakeholders to focus on data and modeling needs. The areas being addressed include types of data that impact offshore wind energy such as wind, wave, and current, and including non-restricted public access to other relevant meteorological parameters. This presentation will update the community on progress of the AMS APT and solicit input to their report. The core sections of the report will include an overview of offshore wind energy opportunities & challenges in the US, the role of met-ocean data in addressing project planning, design & operations, sources of existing measured and modeled data, and data gaps and strategies to address them.