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Sample records for khan basin offshore

  1. Exploration potential of offshore northern California basins

    SciTech Connect

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

    1988-01-01

    A series of exploratory wells was drilled in the northern California offshore basins in the 1960s following leasing of federal tracts off northern California, Oregon, and Washington. The drilling, although encountering numerous oil shows, was considered at the time to indicate low prospectivity in an area that extended as far south as the offshore Santa Maria basin. However, subsequent major discoveries in this decade in the offshore Santa Maria basin, such as the Point Arguello field, indicate that these offshore basins may be highly prospective exploration targets. Many of the key features of Monterey production in central and southern California are also present in the offshore basins of northern California. A new 5-year leasing plan has scheduled leasing in the northern California OCS starting in early 1989. The first basins on the schedule, the Point Arena and Eel River basins, differ in some respects. The Point Arena basin is more typical of a Monterey basin, with the potential for fractured chert reservoirs and organic-rich sections, deep burial of basinal sections to enhance the generation of higher gravity oils, and complex folding and faulting. The Eel River basin is more clastic-rich in its gas-producing, onshore extension. Key questions in the Eel River basin include whether the offshore, more distal stratigraphy will include Monterey-like biogenic sediments, and whether the basin has oil potential in addition to its proven gas potential. The Outer Santa Cruz basin shares a similar stratigraphy, structure, and hydrocarbon potential with the Point Arena basin. The Santa Cruz-Bodega basin, also with a similar stratigraphy, may have less exploration potential because erosion has thinned the Monterey section in parts of the basin.

  2. 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.

  3. 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.

  4. Crustal structure across the Colorado Basin, offshore Argentina

    NASA Astrophysics Data System (ADS)

    Franke, Dieter; Neben, Soenke; Schreckenberger, Bernd; Schulze, Albrecht; Stiller, Manfred; Krawczyk, Charlotte M.

    2006-06-01

    The geology of the wide shelves surrounding the South Atlantic is closely linked to the kinematics and history of the opening of the ocean. However, several wide sedimentary basins, which developed along the margins show peculiarities that are not yet understood in the context of the evolution of the South Atlantic. The Colorado Basin, a wide sedimentary basin on the broad shelf of Argentina, extends in EW direction. The basin's evolution oblique or orthogonal to the continent-ocean boundary indicates that it is not a product of simple progressive extension and crustal thinning. In addition a basement high, paralleling the continental margin and separating the Colorado Basin from the deep-sea basin is a common interpretation. These findings are hardly in accordance with the idea that the Colorado Basin is an extensional basin that developed in conjunction with the early E-W opening phase of the South Atlantic in the Late Jurassic/Early Cretaceous. The composition, type, and structure of the basement, key points for the evaluation of the basins evolution, are widely speculative. In this context multichannel seismic reflection data from the Argentine Shelf and a 665-km-long onshore-offshore refraction profile, running across the Colorado Basin onto the coast are discussed in combination with gravity data. The stratigraphy for the sedimentary successions was adopted from the literature and the reflection seismic marker horizons formed besides the interval velocities the input for the starting model for refraction seismic traveltime modelling. The modelling strategy was an iterative procedure between refraction seismic traveltime and gravity modelling. The preparation of the density models was coarsely orientated on published velocity-density relations. The modelling results are in favour of a continuation of the main onshore geological features beneath the sedimentary infill of the Colorado Basin. We interpret the basement along the line from west to east as offshore

  5. Operators renewing exploration in offshore basins of France

    SciTech Connect

    Lamiraux, C.; Mascle, A.

    1995-07-03

    Forty nine wells were drilled without success from the latter 1960s to the first half of the 1980s in French offshore areas. About 10 years of reduced activity followed this first phase of exploration. For a couple of years, these areas have been closely reassessed, taking into account the experience and data previously acquired. More particularly, a better understanding of tectonic processes at the origin of complex structural traps, a better taking into account of the distribution, quality, and maturation history of source rocks, together with significant improvements in seismic data acquisition-processing and basin modeling techniques, have led a few oil companies to apply for licenses in three offshore areas. The paper discusses prospects in the Bay of Biscay, the Iroise Sea and English Channel, and the Gulf of Lions.

  6. 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.

  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. 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.

  9. 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.

  10. Sequence stratigraphy of the Orange basin, western offshore South Africa

    SciTech Connect

    Muntingh, A. )

    1991-03-01

    A seismic/sequence-stratigraphic framework for the siliciclastic fluvial to deepwater Cretaceous strata of the Orange basin has been constructed. Sequence-stratigraphic concepts developed by Exxon were used to interpret 10,000 km of seismic data and logs from 31 exploration boreholes within an area of 90,000 km{sup 2}. The sequence stratigraphy of the western margin exhibits 34 cyclical depositional sequences interpreted to document the response of the passive margin to cyclical changes in relative sea-level from Mid-Aptian to Late Maastrichtian times. All but one of the sequence boundaries are type 1 unconformities displaying intense erosion on the shelf and interpreted to develop during periods of rapid fall in relative sea-level. Basin-wide sequence boundaries (type 1 and 2 unconformities) were correlated with the third-order cycles of Exxon's global cycle chart utilizing SOEKOR's paleontological dating of a limited number of marine condensed sections. Higher-order cycles are recognized and best developed along the flanks of the structural arches where lower subsidence rates permitted impact of higher frequency cycles. Component depositional systems tracts inferred to have resulted from changes in relative sea level were interpreted and paleogeographic maps were constructed outlining incised valley systems on the shelf, shelf edge canyons, prograding wedges, basin floor fan, and slope fan systems. Distal marine shales and marine condensed sections provide both seal and hydrocarbon source. The chronostratigraphic and depositional framework being used to predict prospective play areas for hydrocarbon exploration on the western offshore of South Africa is also applicable to the Namibian offshore.

  11. 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.

  12. 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

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    The Offshore Sydney Basin is located between latitudes 32°30'S and 34°30'S between the coastal cities of Newcastle in the north and Wollongong in the south, covering a total area of ~15,000 squire km. The structural framework of the offshore portion of the basin comprises five principal elements: the Offshore Syncline, an extension of the New England Fold Belt, an offshore extension of the Newcastle Syncline, the Offshore Uplift and the Outer Continental Shelf. The present easterly extent of the basin is the result of Cretaceous rifting and commencement of seafloor spreading in the adjacent Tasman Sea. The continental shelf is approximately 50 km wide offshore Sydney and is edged by relatively steep continental slope. This study has been carried out with 2D multichannel seismic data covering the northern half of the offshore basin. The Cenozoic sedimentary cover of the basin is characterized by two regional unconformities: one at the base of Cenozoic and another intra-Cenozoic. The unconformity at the base of Cenozoic is known as the Top Sydney Basin unconformity. In places the surface is displaced by faults and also characterized by possible mounds producing an overall highly irregular topography. Though most of the faults remained buried beneath the surface some continued up to seafloor. They seem to have NW-SE direction with significant lateral extension. The intra-Cenozoic unconformity forms a prominent reflector at about 80 to 200 msbs (TWT). It is characterized by an angular unconformity with the reflectors terminating onto it from beneath. It is also associated with prograding sequences beneath, terminating with toplap geometry, suggesting that it forms the boundary between a transgressive and regressive phase. This is interpreted as a prograding carbonate dominated shelf-edge. The most interesting aspect of this seismic reflector is that the major part of it presents reverse polarity with respect to the seafloor reflection. The amplitude of the reflector

  14. 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.

  15. Geological history of the Flemish Pass Basin, offshore Newfoundland

    SciTech Connect

    Foster, D.G.; Robinson, A.G. )

    1993-04-01

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

  16. Geology, prospects in Orange basin offshore western South Africa

    SciTech Connect

    Muntingh, A. Ltd., Parow )

    1993-01-25

    With the fast changing political situation in South Africa it has become possible for Soekor (Pty.) Ltd. To invite international companies to participate in oil and gas exploration in the South African part of the Orange basin. This paper reports on the Orange basin, which comprises a 130,000 sq km area off western South Africa that extends northwards into Namibia, represents a large frontier basin with known hydrocarbon accumulations and the potential for giant fields. Comprehensive seismic coverage and a recent deep-water seismic survey in the Orange basin indicate exciting opportunities in the form of shallow and deep-water plays.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  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.

    1996-12-31

    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.

  4. 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.

  5. 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

  6. [A search for a "Genghis Khan chromosome"].

    PubMed

    Zakharov, I A

    2010-09-01

    Zerial et al. (2003) have shown that a special variant of the Y chromosome, characterized by a set of microsatellite markers occurs at high frequency in the number of human populations of Central Asia. This variant was attributed to the descendants of Genghis Khan and its accumulation, to social selection. A search of this Y chromosome variant in Russian populations was conducted. The "Genghis Khan Y chromosome" has been found among Altaians, Altai Kazakhs, Buryats, Kalmyks, Nogaits, and Tuvinians. Its highest frequency (13.8%) was observed in Nogaits. In the examined cases the carriers of the "Genghis Khan Y chromosome" possessed no information on their origin.

  7. Subsidence history and tectonic evolution of Campos basin, offshore Brazil

    SciTech Connect

    Mohriak, W.U.; Karner, G.D.; Dewey, J.F.

    1987-05-01

    The tectonic component of subsidence in the Campos basin reflects different stages of crustal reequilibration subsequent to the stretching that preceded the breakup of Pangea. Concomitant with rifting in the South Atlantic, Neocomian lacustrine rocks, with associated widespread mafic volcanism, were deposited on a vary rapidly subsiding crust. The proto-oceanic stage (Aptian) is marked by a sequence of evaporitic rocks whose originally greater sedimentary thickness is indicated by residual evaporitic layers with abundant salt flow features. An open marine environment begins with thick Albian/Cenomanian limestones that grade upward and basinward into shales. This section, with halokinetic features and listric detached faulting sloping out on salt, is characterized by an increased sedimentation rate. The marine Upper Cretaceous to Recent clastic section, associated with the more quiescent phase of thermal subsidence, is characterized by drastic changes in sedimentation rate. Stratigraphic modeling of the sedimentary facies suggests a flexurally controlled loading mechanism (regional compensation) with a temporally and spatially variable rigidity. Locally, the subsidence in the rift-phase fault-bounded blocks shows no correspondence with the overall thermal subsidence, implying that the crust was not effectively thinned by simple, vertically balanced stretching. Deep reflection seismic sections show a general correspondence between sedimentary isopachs and Moho topography, which broadly compensates for the observed subsidence. However, even the Moho is locally affected by crustal-scale master faults that apparently are also controlling the movement mechanisms during the rift-phase faulting.

  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. Numerical Modeling of Petroleum Generation and Accumulation in the Sora Basin, Offshore Southern Korea

    NASA Astrophysics Data System (ADS)

    Son, Byeong-Kook; Lee, Seul-A.; Park, Mee-Sook

    2015-04-01

    Petroleum system modeling calculates and visualizes how and when hydrocarbons generate, migrate, and accumulate in a sedimentary basin. Therefore, it can be used effectively to predict the future prospects of oil and gas based on the understanding of the petroleum system in time and space. The petroleum system modeling was performed on the Sora Basin which is a small Cenozoic basin located offshore southern Korea, also including the offshore area of western Kyushu, Japan. Oil and gas shows were detected in two wells drilled in the basin, indicating that petroleum systems are present in the basin. Input parameters were selected from the well data as well as previous geological and geophysical studies for the 1-D model, from which thermal parameters such as heat flow and thermal maturity are also calculated and applied to 2-D model. The 2-D modeling was performed on an E-W seismic section across the basin from western margin in the Korea Block to eastern margin in Japanese Block. The PetroMod software was employed in the 2-D modeling, and stratigraphy, including lithology and organic content, was obtained from the wells and previous geological studies. 2-D modeling shows that hydrocarbons were expelled from the pod of the Eocene source rock in the Miocene time. The hydrocarbons migrate vertically along faults to the upper Oligocene sandstone formation, rather than the updip migrations along the sandstone bed, and hence form small-sized accumulations in the upper part of the sandstone formation. 3-D model was also performed based on depth maps of each formation in the Sora basin. Hydrocarbons are generated and expelled from the pod of the source rock of Eocene formation from 32Ma. In addition, the 3-D model shows that the hydrocarbon migrates northwestward and eastward in the carrier bed of sandstone. The petroleum models indicate that only a small amount of hydrocarbons are accumulated in the reservoir formation, probably due to small size of the basin and low degree

  11. 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.

  12. 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…

  13. Tectono-stratigraphic analysis of the Malvinas Basin, offshore the southernmost Argentinean continental margin

    NASA Astrophysics Data System (ADS)

    Baristeas, N.; Anka, Z.; di Primio, R.; Rodriguez, J. F.; Marchal, D.; Dominguez, F.

    2012-04-01

    A detailed tectono-stratigraphic analysis of the Malvinas Basin development, located offshore the Argentinean margin, was carried out. This was achieved through the interpretation of around 65,000 km of 2D seismic reflection profiles, spanning a dense grid on the shelf and the upper-slope of the basin. Five main seismo-stratigraphic units and their sub-units, informally named U1 to U5 a/b, bound by major unconformities were identified and correlated with the Mesozoic to Cenozoic main tectonic phases of the basin. U1 (Pre-168 Ma) represents the seismic basement and deepens gradually southwards. U2 (168-150.5 Ma, syn rift phase) fills regional depressions, onlapping the basement, and it thickens and deepens southwards. U1 and U2 are affected by several syn-rift normal faults, which have a main NE-SW strike direction in the south of the basin and a NW-SE strike direction in the centre of the basin. This suggests that the Malvinas Basin may have been developed initially as a rift basin with two different extensional directions. (1) a NW-SE directed extension probably linked with the opening of the Weddell Sea (Early Mid-Jurassic) and (2) a NE-SW directed extension most likely linked with the opening of the South Atlantic during Mid-Jurassic to Early Cretaceous. U3 (150.5-68 Ma, sag phase) is mainly an aggradational wedge-shaped unit. Some syn-rift faults continue into the Cretaceous. Sedimentation in this unit is mainly derived from the north and during Mid-Cretaceous also from the northeast, as documented by the presence of a southwestward prograding sedimentary fan located in the northeast of the basin. U4 (68-42.5 Ma, transtensional foredeep phase) overlies unconformly U3 and thickens to the south. Sediment input decreases dramatically during that time and only a thin sedimentary succession was deposited over the entire basin. Although a regional compressional regime is established from late Cretaceous to Cenozoic due to the Andean orogenesis, an extensional regime

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. Onshore-Offshore Fault Correlation: An Integrated Approach for Understanding Basin Evolution

    NASA Astrophysics Data System (ADS)

    Hansen, J. A.; Bergh, S.; Henningsen, T.; Olesen, O.

    2008-12-01

    The Lofoten and Vesterålen passive continental margin in north Norway records prolonged rifting during the Mesozoic, leading to final separation and formation of the Norwegian-Greenland Sea in the early Eocene. The islands of Lofoten and Vesterålen represent exposed basement highs, being an integral part of this margin. This makes it the ideal location for onshore-offshore investigations. In this study we integrate offshore seismic data and stratigraphy, bathymetry, potential field data onshore- offshore, onshore lineament analysis, digital elevation models, AFT age data and fault/fracture mapping. This allows us to correlate the offshore and onshore fault system(s), infer timing and kinematics of rifting, and investigate potential basement control of fault development. Our results indicate that the Mid/Late Jurassic to early Cretaceous rifting initiated in the Callovian (possibly Bathonian) as a result of E-W directed extension, and was followed by a period of tectonic quiescence or reduced tectonic activity in Volgian to Berriasian times, with renewed rifting in the Valanginian lasting up to the late Early Cretaceous. These rifting events resulted in the development of major fault-bounded basins, delineated by N-S to NNE-SSW striking normal faults linked by ENE-WSW striking transfer faults, together defining a zig-zag fault pattern in map view. Onshore the ENE-WSW striking fault zones tend to follow pre- existing (ductile) basement fabric while the N-S to NNE-SSW striking faults often cut the basement fabric. This indicates that the pre-existing basement fabric played an important role in localizing zones of fault segment linkage and basin segmentation. In the Late Cretaceous the margin was uplifted and eroded until the final rifting event, due to NNW-SSE directed extension, was initiated in the latest Cretaceous and resulted in final breakup in the early Eocene. This last rifting event reactivated and utilized some of the more distal NE-SW to ENE-WSW striking

  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.

    1996-12-31

    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.

  20. 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.

  1. 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.

  2. 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…

  3. 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.

  4. 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.

  5. Shelf sheet-sand reservoir of the lower Cretaceous Greensand, North Celtic Sea Basin, offshore Ireland

    SciTech Connect

    Winn, R.D. Jr.

    1994-11-01

    Core and log data show that the marine, early to middle Albian {open_quotes}A{close_quotes} Sand of the Aptian to lower Cenomanian Greensand-Gault interval, North Celtic Sea Basin, offshore Ireland, was deposited as an approximately tabular sand body in shelf water depths. The {open_quotes}A{close_quotes} Sand is the major reservoir interval at Kinsale Head and Ballycotton gas fields. The reservoir sandstone is bioturbated, variably glauconitic, shell rich, and least muddy toward its provenance in a local area of the Irish massif and finer grained southeastward into the basin. Thickness and coarseness of the {open_quotes}A{close_quotes} Sand are related, in part, to distance from a narrow area of the paleoshore. Bathymetric control of sand thickness was superimposed on proximal-distal trends. Specifically, thick intervals are inferred to have been deposited in shelf lows, and thin zones were deposited over bathymetric highs. The {open_quotes}A{close_quotes} Sand was not deposited as a ridge sand, and positive relief on the depositional sand body appears to have been minor. Deposition of the Greensand occurred during thermal subsidence of the North Celtic Sea Basin following Early Cretaceous rifting. Overall late Early Cretaceous to Late Cretaceous transgression was interrupted by progradation of the {open_quotes}A{close_quotes} Sand, probably caused by a relative drop in sea level (forced regression). The {open_quotes}A{close_quotes} Sand sheet consists of several units within the central depositional basin. Three slightly coarsening-upward units up to 15 m thick probably are the consequence of high-frequency fluctuations in sea level during progradation. The top of the {open_quotes}A{close_quotes} Sand consists of a several-meter-thick, very glauconitic, muddy sandstone to sandy mudstone. The upper unit accumulated in deepening water following the maximum lowstand.

  6. 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…

  7. Interactive interpretation of morphology of upper Tertiary contourites, Porcupine basin, offshore Ireland

    SciTech Connect

    Macurda, D.B.; Nelson, R.

    1989-03-01

    A workstation-based, seismic-stratigraphic study of a series of Miocene-Pliocene sequences in the eastern portion of Porcupine basin, offshore Ireland, reveals the stratigraphic complexities and evolution of a contourite dune. Five seismic facies are present: parallel reflectors, which onlap the continental slope; a mound, with internal prograding oblique reflectors that dip to the southwest; a channel axis, oriented northwest-southeast; a natural levee, on the southwest side of the channel; and parallel or hummocky reflectors, downdip toward the basin center. Morphologically the mound, comprised of prograding clinoforms and channel and levee facies, resembles the point bar, channel, and levee of a terrestrial river meander system. The length of the mound exceeds 50 km; channel widths are as great as 8 km. Internally the mound is comprised of at least six sequences that were deposited episodically. Current flow was southeast, parallel to contours. Interactive mapping and contouring of seismic sequences, using paper and a seismic workstation, allow the shifts of directions of progradation and main depocenters to be detailed through the Miocene-Pliocene interval. Mapping of seismic facies suggests possible variations in environments and lithofacies. Ongoing investigations of contourites suggest that possible end members are morphologically complex and variable. By understanding their variability, the role of contour currents in modifying submarine fans or possibly forming sand facies capable of reservoiring hydrocarbons can be determined.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. The junction of Hellenic and Cyprus arcs: the Bey Daglari lineament, offshore termination of the Antalya Basin

    NASA Astrophysics Data System (ADS)

    Gogacz, A.; Hall, J.; Çifçi, G.; Yaşar, D.; Küçük, M.; Yaltırak, C.; Aksu, A.

    2009-04-01

    The Antalya Basin is one of a series of basins that sweep along the Cyprus Arc in the forearc region between the (formerly) volcanic Tauride Mountains on Turkey in the north and the subduction zone and associated suture between the African plate and the Aegean-Anatolian microplate in the eastern Mediterranean, south of Cyprus. Miocene contraction occurs widely on southwest verging thrusts. Pliocene-Quaternary structures vary from extension/transtension in the northeast, adjacent to the Turkish coastline, to transpression in the southwest, farther offshore. All these structures are truncated at the northwest end of the Antalya Basin by a broad zone of NNE-SSW-trending transverse structure that appears to represent a prolongation of the extreme easterly transform end of the Hellenic arc. Our mapping suggests that this broad zone links the Hellenic Arc with the Isparta Angle in southern Turkey, which we suggest is an earlier location of the junction of Hellenic and Cyprus Arcs: the junction migrated to the southwest over time, as the Hellenic Arc rolled back. The Turkish coastline turns from parallel to the Antalya Basin structures in the east to a N-S orientation, cutting across the trend of the Antalya Basin. The Antalya Complex and the Bey Dağlari Mountains provide a spectacular backdrop to this edge of the offshore basin. Somewhere offshore lies the structural termination of the Antalya Basin. In 2001, we acquired around 400 km of high-resolution multi-channel seismic reflection data across the western end of the Antalya Basin to explore the nature of the termination, which we call the Bey Dağlari lineament. We present a selection of the seismic profiles with interpretation of the nature and Neogene history of the lineament. Landward of the N-S-trending coastline, ophiolites of the Antalya Complex are exposed in a series of westerly-verging thrust slivers that extend to the carbonate sequences of the Bey Dağlari Mountains. Our seismic data indicate that N

  15. The Junction of Hellenic and Cyprus Arcs: the Bey Daglari Lineament, Offshore Termination of the Antalya Basin

    NASA Astrophysics Data System (ADS)

    Gogacz, A.; Hall, J.; Cifci, G.; Yasar, D.; Kucuk, M.; Yaltirak, C.; Aksu, A.

    2009-05-01

    The Antalya Basin is one of a series of basins that sweep along the Cyprus Arc in the forearc region between the (formerly) volcanic Tauride Mountains on Turkey in the north and the subduction zone and associated suture between the African plate and the Aegean-Anatolian microplate in the eastern Mediterranean, south of Cyprus. Miocene contraction occurs widely on southwest verging thrusts. Pliocene-Quaternary structures vary from extension/transtension in the northeast, adjacent to the Turkish coastline, to transpression in the southwest, farther offshore. All these structures are truncated at the northwest end of the Antalya Basin by a broad zone of NNE-SSW-trending transverse structure that appears to represent a prolongation of the extreme easterly transform end of the Hellenic arc. Our mapping suggests that this broad zone links the Hellenic Arc with the Isparta Angle in southern Turkey, which we suggest is an earlier location of the junction of Hellenic and Cyprus Arcs: the junction migrated to the southwest over time, as the Hellenic Arc rolled back. The Turkish coastline turns from parallel to the Antalya Basin structures in the east to a N-S orientation, cutting across the trend of the Antalya Basin. The Antalya Complex and the Bey Dağları Mountains provide a spectacular backdrop to this edge of the offshore basin. Somewhere offshore lies the structural termination of the Antalya Basin. In 2001, we acquired around 400 km of high-resolution multi-channel seismic reflection data across the western end of the Antalya Basin to explore the nature of the termination, which we call the Bey Dağları lineament. We present a selection of the seismic profiles with interpretation of the nature and Neogene history of the lineament. Landward of the N-S-trending coastline, ophiolites of the Antalya Complex are exposed in a series of westerly-verging thrust slivers that extend to the carbonate sequences of the Bey Dağları Mountains. Our seismic data indicate that N

  16. 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.

  17. 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.…

  18. 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…

  19. 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…

  20. 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

  1. Thermotectonic history of the southeastern Brazilian margin: Evidence from apatite fission track data of the offshore Santos Basin and continental basement

    NASA Astrophysics Data System (ADS)

    Engelmann de Oliveira, Christie Helouise; Jelinek, Andréa Ritter; Chemale, Farid; Cupertino, José Antônio

    2016-08-01

    The Santos Basin is the largest offshore sedimentary basin in the southeastern Brazilian margin and originated by breakup of West Gondwana in the Early Cretaceous. We carried out a new thermochronological study by apatite fission track analysis from borehole samples of the Santos Basin and its continental basement to constrain the tectonic history of the southeastern Brazilian margin. Apatite fission track central ages of the basement and borehole samples vary from 21.0 ± 1.8 to 157.0 ± 35.0 Ma and from 6.5 ± 1.1 to 208.0 ± 11.0 Ma, respectively. From thermal modeling, the basement samples reached the maximum paleotemperatures during the final breakup of South America and Africa. The onshore basement and offshore basin record an early thermotectonic event during the Late Cretaceous linked to the uplift and denudation of the Serra do Mar and Serra da Mantiqueira. Maturation of the organic matter in the offshore basin is related with the progressive increase of the geothermal gradient due to burial. The thermal modeling indicates that the oil generation window started at 55-25 Ma. The basement samples experienced the final cooling during the Cenozoic, with an estimated amount of denudation linked to the sedimentary influx in the offshore basin. A rapid cooling during the Neogene becomes evident and it is linked to the reactivation along Precambrian shear zones and change of the Paraíba do Sul drainage system.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Chemistry and origin of Miocene and Eocene oils and tars in the onshore and offshore Santa Cruz Basins, California

    SciTech Connect

    Kornacki, A.S.; McNeil, R.I.

    1996-12-31

    The Santa Cruz (La Honda) Basin is a small {open_quote}slice{close_quote} of the San Joaquin Basin that has been displaced c. 300 km to the northwest by the San Andreas Fault. The poorly-explored offshore area that now lies within the Monterey Bay NMS includes portions of the Outer Santa Cruz and Bodega basins. A modest amount (c. 1.3 MM bbl) of variable-quality oil has been produced from Eocene and Pliocene pay zones in the La Honda Field. Much smaller amounts of light oil ({ge}40{degrees} API) have been produced from three other fields (Oil Creek; Moody Gulch; Half Moon Bay). Large tar deposits also outcrop near the city of Santa Cruz. Proven source rocks in this basin include the Eocene Twobar Shale and three Miocene units: the Lambert Shale, Monterey Formation, and the Santa Cruz Mudstone. A high-gravity oil sample from the Oil Creek Field contains isotopically-light carbon ({delta}{sup 13}C = - 28.2 per mil) and has a relatively high pristane/phytane ratio. This oil was generated at high temperature (c. 140{degrees}C) by pre-Miocene source rocks (probably the Twobar Shale). The presence of isotopically-heavy carbon in all other oil and tar samples demonstrates they were generated by Miocene source rocks. But the C{sub 7} oil-generation temperatures, sulfur content, vanadium/nickel ratios, and biomarker chemistry of these Miocene oils are significantly different than in Monterey oils from the prolific Santa Maria Basin (SMB). The sulfur content (8.0 wt%) and V-Ni chemistry of tarry petroleum recovered in the P-036-1 well (Outer Santa Cruz Basin) resembles the chemistry of very heavy (<15{degrees}API) oils generated by phosphatic Monterey shales in the SMB.

  9. Chemistry and origin of Miocene and Eocene oils and tars in the onshore and offshore Santa Cruz Basins, California

    SciTech Connect

    Kornacki, A.S. ); McNeil, R.I. )

    1996-01-01

    The Santa Cruz (La Honda) Basin is a small [open quote]slice[close quote] of the San Joaquin Basin that has been displaced c. 300 km to the northwest by the San Andreas Fault. The poorly-explored offshore area that now lies within the Monterey Bay NMS includes portions of the Outer Santa Cruz and Bodega basins. A modest amount (c. 1.3 MM bbl) of variable-quality oil has been produced from Eocene and Pliocene pay zones in the La Honda Field. Much smaller amounts of light oil ([ge]40[degrees] API) have been produced from three other fields (Oil Creek; Moody Gulch; Half Moon Bay). Large tar deposits also outcrop near the city of Santa Cruz. Proven source rocks in this basin include the Eocene Twobar Shale and three Miocene units: the Lambert Shale, Monterey Formation, and the Santa Cruz Mudstone. A high-gravity oil sample from the Oil Creek Field contains isotopically-light carbon ([delta][sup 13]C = - 28.2 per mil) and has a relatively high pristane/phytane ratio. This oil was generated at high temperature (c. 140[degrees]C) by pre-Miocene source rocks (probably the Twobar Shale). The presence of isotopically-heavy carbon in all other oil and tar samples demonstrates they were generated by Miocene source rocks. But the C[sub 7] oil-generation temperatures, sulfur content, vanadium/nickel ratios, and biomarker chemistry of these Miocene oils are significantly different than in Monterey oils from the prolific Santa Maria Basin (SMB). The sulfur content (8.0 wt%) and V-Ni chemistry of tarry petroleum recovered in the P-036-1 well (Outer Santa Cruz Basin) resembles the chemistry of very heavy (<15[degrees]API) oils generated by phosphatic Monterey shales in the SMB.

  10. 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.

  11. 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

  12. Hydrocarbon formation and migration in the volcanic Møre and Vøring basins offshore Norway

    NASA Astrophysics Data System (ADS)

    Planke, S.; Aarnes, I.; Svensen, H.; Polteau, S.

    2010-12-01

    Voluminous igneous sheet intrusions were emplaced in low quality Cretaceous source rocks in the Vøring and Møre basins offshore Norway about 55.8 million years ago. We show that several hundred gigatons of carbon gas can be formed as a result of contact metamorphism in the basin during the intrusive event based on studies of borehole data and numerical modeling. The numerical modeling further shows that multiple sill intrusions emplaced at the same time increase the gas generation potential by up to 35 % relative to intrusions emplaced sequentially. The gas migrated out of the aureoles by two mechanisms. (1) The major gas release occurred immediately after the gas was generated through thousands of hydrothermal vent complexes, and may have caused disruption in the global carbon cycle triggering the Paleocene-Eocene thermal maximum (PETM). (2) The second mechanism involves slow gas seepage, occasionally to the seafloor, in the Eocene to the Paleogene forming seep carbonates and hydrocarbon deposits. In addition, significant volumes of aureole gas (dry gas and CO2-rich gas) are still likely trapped in the source rocks as shale gas. Our results are important to understand petroleum systems in volcanic basins and the cause of rapid climate changes and mass extinctions in Earth history.

  13. 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.

  14. Sea-level and tectonic control of middle to late Pleistocene turbidite systems in Santa Monica Basin, offshore California

    USGS Publications Warehouse

    Normark, W.R.; Piper, D.J.W.; Sliter, R.

    2006-01-01

    Small turbidite systems offshore from southern California provide an opportunity to track sediment from river source through the turbidity-current initiation process to ultimate deposition, and to evaluate the impact of changing sea level and tectonics. The Santa Monica Basin is almost a closed system for terrigenous sediment input, and is supplied principally from the Santa Clara River. The Hueneme fan is supplied directly by the river, whereas the smaller Mugu and Dume fans are nourished by southward longshore drift. This study of the Late Quaternary turbidite fill of the Santa Monica Basin uses a dense grid of high-resolution seismic-reflection profiles tied to new radiocarbon ages for Ocean Drilling Program (ODP) Site 1015 back to 32 ka. Over the last glacial cycle, sedimentation rates in the distal part of Santa Monica Basin averaged 2-3 mm yr-1, with increases at times of extreme relative sea-level lowstand. Coarser-grained mid-fan lobes prograded into the basin from the Hueneme, Mugu and Dume fans at times of rapid sea-level fall. These pulses of coarse-grained sediment resulted from river channel incision and delta cannibalization. During the extreme lowstand of the last glacial maximum, sediment delivery was concentrated on the Hueneme Fan, with mean depositional rates of up to 13 mm yr-1 on the mid- and upper fan. During the marine isotope stage (MIS) 2 transgression, enhanced rates of sedimentation of > 4 mm yr-1 occurred on the Mugu and Dume fans, as a result of distributary switching and southward littoral drift providing nourishment to these fan systems. Longer-term sediment delivery to Santa Monica Basin was controlled by tectonics. Prior to MIS 10, the Anacapa ridge blocked the southward discharge of the Santa Clara River into the Santa Monica Basin. The pattern and distribution of turbidite sedimentation was strongly controlled by sea level through the rate of supply of coarse sediment and the style of initiation of turbidity currents. These two

  15. Explanation for the occurrence of biodegraded oil in the Jeanne d`Arc Basin, offshore eastern Canada

    SciTech Connect

    Fowler, M.G.; Williamson, M.A.

    1996-10-01

    Several discoveries of biodegraded oil have been made in the Jeanne d`Arc: Basin, offshore eastern Canada. All have the same Kimmeridgian-aged source rock. Plots of oil saturation versus permeability suggest that biodegradation took place in the reservoir. Some pools contain just one phase of biodegraded oil. Other reservoirs show a mixture of lower maturity biodegraded oil and higher maturity undegraded oil. Geochemical and fluid inclusion data, supported by migration modelling, indicates the following scenario for these occurrences. An initial hydrocarbon generation and migration phase during the Late Cretaceous-early Tertiary, followed by a fall in sea-level coupled to some uplift and erosion on the flanks of the basin which allowed meteoric waters to penetrate deeper into the subsurface thus breaching recently charged reservoirs. Subsidence resumed during late Eocene resulting in a second expulsion/migration phase of more mature hydrocarbons that migrated either into traps that had already been charged and biodegraded, or into newly formed traps.

  16. 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.

  17. 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.

  18. 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.

  19. 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).

  20. Offshore remobilization processes and deposits in low-energy temperate-water carbonate-ramp systems: Examples from the Neogene basins of the Betic Cordillera (SE Spain)

    NASA Astrophysics Data System (ADS)

    Puga-Bernabéu, Ángel; Martín, José M.; Braga, Juan C.; Aguirre, Julio

    2014-05-01

    General facies models developed for modern and ancient Mediterranean temperate-water carbonates in the last two decades have shown that the style of deposition on outer-ramp, slope, and basin environments in low-energy areas such as the Mediterranean Sea differs overall from that of high-energy open-ocean areas, given the wider variety of smaller-scale topographic and hydrodynamic conditions in the former setting. However, these depositional models generally lack relevant information about sedimentary processes, transport mechanisms and controlling factors on offshore sediment redeposition, which are potential sources of information for sequence stratigraphic, palaeoclimate and exploration studies. Several examples from the Neogene Betic basins of the western Mediterranean region have been selected to integrate the processes and controlling factors on the offshore sediment transport and the resulting deposits. Additional published data from other Mediterranean localities have also been considered.

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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…

  6. 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

  7. Geology of offshore southern Namibia: Evidence from tectonic and basin-fill modeling based on modern seismic data

    SciTech Connect

    Houghton, M.L.; Peacock, D.N. )

    1993-09-01

    License 2815 is located offshore southern Namibia between Cape Dernberg and the South African border, approximately 50 km east of the 1974 Kudu gas discovery. Interactive workstation modeling of modern two-dimensional seismic data from the License area provides an improved understanding of the geology and tectonic history of this unexplored region. Although presently a broad submarine shelf influenced by late Cretaceous-Tertiary deltaic sedimentation from the Orange River, Interpretation based on modern seismic coverage has resulted in the recognition of a Late Jurassic-Early Cretaceous rift complex associated with the initial opening of the Atlantic Ocean. Geologic modeling suggests that a seismically-identified elongate rift localized along a major westward-dipping bounding fault may contain significant thicknesses of Neocomian( ) clastic sediments. Barremian-Aptian marine flooding of this area followed the rifting episode. Mixed marine and deltaic sedimentation has dominated the region since the middle Aptian. Palinspastic restorations of depth-converted seismic lines have helped to unravel the episodic tectonic history of rifting in this area. Input of geologic parameters, including relative sea level changes and sedimentation rates, has yielded computer-derived basin-fill models, which have in turn been integrated with the local tectonic model to make lithology predictions.

  8. Pockmark asymmetry and seafloor currents in the Santos Basin offshore Brazil

    NASA Astrophysics Data System (ADS)

    Schattner, U.; Lazar, M.; Souza, L. A. P.; ten Brink, U.; Mahiques, M. M.

    2016-09-01

    Pockmarks form by gas/fluid expulsion into the ocean and are preserved under conditions of negligible sedimentation. Ideally, they are circular at the seafloor and symmetrical in profile. Elliptical pockmarks are more enigmatic. They are associated with seafloor currents while asymmetry is connected to sedimentation patterns. This study examines these associations through morphological analysis of new multibeam data collected across the Santos continental slope offshore Brazil in 2011 (353-865 mbsl). Of 984 pockmarks, 78% are both elliptical and asymmetric. Geometric criteria divide the pockmarks into three depth ranges that correlate with a transition between two currents: the Brazil Current transfers Tropical Water and South Atlantic Central Water southwestwards while the Intermediate Western Boundary Current transfers Antarctic Intermediate Water northeastwards. It is suggested that the velocity of seafloor currents and their persistence dictate pockmark ellipticity, orientation and profile asymmetry. Fast currents (>20 cm/s) are capable of maintaining pockmark flank steepness close to the angle of repose. These morphological expressions present direct evidence for an edge effect of the South Atlantic Subtropical Gyre and, in general, provide a correlation between pockmark geometry and seafloor currents that can be applied at other locations worldwide.

  9. Pockmark asymmetry and seafloor currents in the Santos Basin offshore Brazil

    USGS Publications Warehouse

    Schattner, U.; Lazar, M.; Souza, L. A. P.; Brink, Uri ten; Mahiques, M. M.

    2016-01-01

    Pockmarks form by gas/fluid expulsion into the ocean and are preserved under conditions of negligible sedimentation. Ideally, they are circular at the seafloor and symmetrical in profile. Elliptical pockmarks are more enigmatic. They are associated with seafloor currents while asymmetry is connected to sedimentation patterns. This study examines these associations through morphological analysis of new multibeam data collected across the Santos continental slope offshore Brazil in 2011 (353–865 mbsl). Of 984 pockmarks, 78% are both elliptical and asymmetric. Geometric criteria divide the pockmarks into three depth ranges that correlate with a transition between two currents: the Brazil Current transfers Tropical Water and South Atlantic Central Water southwestwards while the Intermediate Western Boundary Current transfers Antarctic Intermediate Water northeastwards. It is suggested that the velocity of seafloor currents and their persistence dictate pockmark ellipticity, orientation and profile asymmetry. Fast currents (>20 cm/s) are capable of maintaining pockmark flank steepness close to the angle of repose. These morphological expressions present direct evidence for an edge effect of the South Atlantic Subtropical Gyre and, in general, provide a correlation between pockmark geometry and seafloor currents that can be applied at other locations worldwide.

  10. "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…

  11. Coastal waters environmental monitoring supported by river basin pluviometry and offshore wave data.

    PubMed

    Abramic, Andrej; Martínez-Alzamora, Nieves; González del Rio Rams, Julio; Ferrer Polo, José

    2015-03-15

    Environmental monitoring in the scope of the Water Framework Directive 2000/60/EC (WFD) is usually expensive and requires considerable human effort. In this study, we analyzed data obtained by a WFD coastal waters monitoring network over a three-year period (35 campaigns), with the aim to ascertain is it possible to increase the monitoring efficiency and obtain more accurate results. As the trophic condition of the coastal waters of Valencia is primarily, but not entirely, determined by continental loads and hydrodynamic conditions, additionally we analyzed related river basin pluviometry (daily frequency) and oceanographic (one hour frequency) data. Chlorophyll a, salinity, rain and wave data time series were analyzed separately, to identify any possible pattern. Analyzing coastal water bodies integrating all four parameters, it is found strong interactions between coastal waters trophic conditions, sea hydrodynamics and related basin pluviometry. Eight phytoplankton biomass scenarios associated to environmental conditions are identified and finally developed basis for a new efficient monitoring strategy and more accurate coastal waters assessment.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. Facies characterization and sequential evolution of an ancient offshore dunefield in a semi-enclosed sea: Neuquén Basin, Argentina

    NASA Astrophysics Data System (ADS)

    Veiga, Gonzalo D.; Schwarz, Ernesto

    2016-08-01

    This study analyses a 30-m-thick, sand-dominated succession intercalated between offshore mudstones in the Lower Cretaceous record of the Neuquén Basin, Argentina, defining facies associated with unidirectional currents as sand dunes (simple and compound), rippled sand sheets and heterolithic sheets. These facies associations are related to the development of an offshore, forward-accreting dunefield developed as a response to the onset of a tidal-transport system. The reported stratigraphic record results from the combination of the gradual downcurrent decrease of the current speed together with the long-term climbing of the entire system. Maximum amplification of the tidal effect associated with incoming oceanic tides to this epicontinental sea would develop at the time of more efficient connection between the basin and the open ocean. Thus, the onset of the offshore tidal system approximately corresponds to the time of maximum flooding conditions (or immediately after). The short-term evolution of the tidal-transport system is more complex and characterized by the vertical stacking of small-scale cycles defined by the alternation of episodes of construction and destruction of the dunefield. The development of these cycles could be the response to changes in tidal current speed and transport capacity.

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. The marine geology of the eastern Santa Barbara Channel, with particular emphasis on the ground water basins offshore from the Oxnard Plain, Southern California

    USGS Publications Warehouse

    Greene, H. Gary; Wolf, Stephen C.; Blom, Ken G.

    1978-01-01

    Marine geophysical investigations provide new data concerning the stratigraphy, tectonic and sedimentary history, and the ground water geology of the southeastern Santa Barbara Channel region. The offshore stratigraphy identified in seismic reflection profiles includes a succession of Neogene to Quaternary strata. The middle Miocene Conejo volcanics form an acoustical basement and the overlying late Cenozoic sedimentary rocks attain a thickness greater than 2,500 m. These sedimentary deposits fill a structurally controlled, physiographic and depositional depression called the Ventura Basin. Structure consists generally of a gently folded, east-trending Tertiary synclinorium bordered on the north by a regional thrust fault and on the south by a steep asymmetrical anticlinal ridge. Most structures show evidence of north-south compression that occurred during early Pleistocene time. Three well-defined unconformities represent widespread erosion in late Miocene, early to middle Pleistocene, and late Pleistocene time. The boundaries of Miocene, Pliocene, and lower Pleistocene strata continue uninterrupted eastward along the southern part of Santa Barbara basin to Hueneme Canyon, where they turn northeast and can be traced to the coast near Port Hueneme. These limits probably represent the south edge of the Santa Barbara basin during Pliocene and Pleistocene time. Fresh water-bearing materials of the Oxnard plain are unconsolidated Quaternary sediment laid down on more consolidated Tertiary rocks. Offshore, the total fresh water-bearing materials distinguished in the seismic reflection profiles attain a thickness of about 356 m and have an areal extent of over 760 km2. Strata that contain the offshore continuation of the five major on-land aquifers (Grimes Canyon, Fox Canyon, Hueneme, Mugu, and Oxnard aquifers) are identified in the seismic reflection profiles. These strata make up the two offshore ground-water basins, the Mound and Oxnard plain ground-water basins

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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.

  11. 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.

  12. 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.

  13. Type 1 and Type 2 unconformity development in response to differential subsidence rates and eustatic sea level fluctuations, Pletmos basin, offshore South Africa

    SciTech Connect

    Jollands, A. )

    1989-03-01

    The Pletmos basin, offshore South Africa, has had variable subsidence rates from mid-Valanginian to mid-Campanian times. During this period, third-, fourth-, and fifth-order sea level fluctuations occurred. The interplay of eustasy and differential subsidence rates caused 67 unconformities. Seventeen are major type 1 unconformities, 44 are minor type 1 unconformities, and 3 are type 2 unconformities. A further three exhibit type 2 characteristics and grade laterally into equivalent type 1 unconformities. Slow subsidence rates permitted fourth- and fifth-order eustatic variations to move sea level below the shelf edge and to erode minor type 1 unconformities. Periodically, when higher order cycles coincided with the trough of a third-order cycle, major type 1 unconformities occurred. Later periods of rapid subsidence precluded fourth- and fifth-order cycles being recorded in the stratigraphic section, and only third-order cycles were interpreted. When the rate of third-order eustatic falls were of the same order of magnitude as subsidence rates, relative sea level did not shift beyond the shelf edge, resulting in type 2 erosion. Deep-seated growth faulting established differential subsidence rates in the central Pletmos basin. In areas of slow subsidence the effects of eustatic variations were amplified relative to areas of rapid subsidence. This resulted in enhanced erosion associated with the former where major and minor type 1 unconformities coalesce and type 2 unconformities grade laterally into equivalent type 1 unconformities.

  14. Recognition of seismic facies, genetic elements, and depositional environments in lowstand system tracts, Pletmos basin, offshore South Africa

    SciTech Connect

    Pferdekamper, H.W.

    1989-03-01

    Postrift Cretaceous strata in the Pletmos basin comprise 67 cyclic depositional sequences that were deposited in response to third-, fourth-, and perhaps fifth-order sea level oscillations. Seismic facies characteristics, identified by analyzing 200 seismic profiles totaling 7000 km, depict an extensive spectrum of lowstand lithogenetic elements and inferred clastic depositional systems. Mid-Valanginian to late Hauterivian lowstand deposition was generally restricted to submarine channel infill and mounded and/or sheetlike marine fill lapping out onto type 1 unconformities. Deposition took place during falling sea level during valley and submarine canyon incision. The rarity of lowstand progradation reflects sea level rises that exceeded sediment supply. Late Hauterivian to middle Aptian areally restricted prograding wedges were deposited in response to apparent equilibrium between fluvial lowstand sediment input, basin subsidence, and slow sea level rise. The wedges clearly exhibit coastal onlap onto type 1 unconformities and pinch out updip against a relict shelf edge. High-angle, oblique clinothems with associated toplap are common and indicate active lowstand deltaic progradation. Clinothems may baselap onto (1) channelized slope fans typified by marine onlap and chaotic reflections, (2) mounded basin-floor fans, or (3) the basin floor itself. Detached mounded basin-floor fans distal from lowstand wedges are numerous throughout the sequences. Excellent seismic data quality and moderate to shallow depths of burial permitted resolution of the genetic elements of lowstand system tracts in this unique tectonic setting.

  15. 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

  16. New insights into the tectono-stratigraphic evolution of the Malvinas Basin, offshore of the southernmost Argentinean continental margin

    NASA Astrophysics Data System (ADS)

    Baristeas, N.; Anka, Z.; di Primio, R.; Rodriguez, J. F.; Marchal, D.; Dominguez, F.

    2013-09-01

    A detailed tectono-stratigraphic analysis of the Malvinas Basin was achieved by the interpretation of around 65,000 km of 2D seismic reflection profiles. Five main seismo-stratigraphic units and their sub-units, informally named units U1 to U5 a/b, bound by major unconformities were identified and correlated with the Mesozoic to Cenozoic main tectonic phases of the basin. Unit U1 (Pre-168 Ma) represents the seismic basement. Unit U2 (168-150.5 Ma, syn rift phase) thickens and deepens southwards. Units U1 and U2 are affected by several syn-rift normal faults that exhibit a main NE-SW strike direction in the south of the basin and a NW-SE strike direction in the centre of the basin. This suggests that the Malvinas Basin may have developed initially as a rift basin with two different extensional directions: (1) a NW-SE directed extension probably linked with the opening of the Weddell Sea (Early Mid-Jurassic), and (2) a NE-SW directed extension most likely linked with the Jurassic back-arc extension of Gondwana and probably later with the onset of the opening of the South Atlantic during Late Jurassic to Early Cretaceous time. Unit U3 (150.5-68 Ma, sag phase) is mainly an aggradational wedge-shaped unit. Unit U4 (68-42.5 Ma, transtensional foredeep phase) overlies unconformable unit U3. It deepens in the south because of an N-S/NW-SE directed extensional regime. Accumulation rates decrease during units U2, U3, and U4 from 4.84, to 1.23 to 0.8 km3/Ma × 103. Units U5a and U5b (42.5-5.5 and 5.5-0 Ma, transpressional foredeep phase) finally represent a change from aggradation to progradation sedimentary pattern and to a left-lateral transpressional regime in the south. The sediment supply was considerably higher than before and a thick sedimentary wedge has been deposited until today. Accumulations rates increased in units U5a and U5b from 2.28 to 8.91 km3/Ma × 103.

  17. 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.

  18. Crowdsourcing the unknown: the satellite search for Genghis Khan.

    PubMed

    Lin, A Y M; 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.

  19. 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

  20. Crowdsourcing the unknown: the satellite search for Genghis Khan.

    PubMed

    Lin, A Y M; 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

  1. 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.; 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.

  2. 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

  3. Sandstone and shale compaction curves derived from sonic and gamma ray logs in offshore wells, North Slope, Alaska; parameters for basin modeling

    USGS Publications Warehouse

    Rowan, Elisabeth L.; Hayba, Daniel O.; Nelson, Philip H.; Burns, W. Matthew; Houseknecht, David W.

    2003-01-01

    Representative compaction curves for the principle lithologies are essential input for reliable models of basin history. Compaction curves influence estimates of maximum burial and erosion. Different compaction curves may produce significantly different thermal histories. Default compaction curves provided by basin modeling packages may or may not be a good proxy for the compaction properties in a given area. Compaction curves in the published literature span a wide range, even within one lithology, e.g., sandstone (see Panel 3). An abundance of geophysical well data for the North Slope, from both government and private sources, provides us with an unusually good opportunity to develop compaction curves for the Cretaceous-Tertiary Brookian sandstones, siltstones, and shales. We examined the sonic and gamma ray logs from 19 offshore wells (see map), where significant erosion is least likely to have occurred. Our data are primarily from the Cretaceous-Tertiary Brookian sequence and are less complete for older sequences. For each well, the fraction of shale (Vsh) at a given depth was estimated from the gamma ray log, and porosity was computed from sonic travel time. By compositing porosities for the near-pure sand (Vsh99%)from many individual wells we obtained data over sufficient depth intervals to define sandstone and shale 'master' compaction curves. A siltstone curve was defined using the sonic-derived porosities for Vsh values of 50%. These compaction curves generally match most of the sonic porosities with an error of 5% or less. Onshore, the curves are used to estimate the depth of maximum burial at the end of Brookian sedimentation. The depth of sonic-derived porosity profiles is adjusted to give the best match with the 'master' compaction curves. The amount of the depth adjustment is the erosion estimate. Using our compaction curves, erosion estimates on the North Slope range from zero in much of the offshore, to as much as 1500 ft along the coast, and to

  4. 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

  5. [Distribution of the male lineages of Genghis Khan's descendants in northern Eurasian populations].

    PubMed

    Derenko, M V; Maliarchuk, B A; Wozniak, M; Denisova, G A; Dambueva, I K; Dorzhu, C M; Grzybowski, T; Zakharov, I A

    2007-03-01

    Data on the variation of 12 microsatellite loci of Y-chromosome haplogroup C3 were used to screen lineages included in the cluster of Genghis Khan's descendants in 18 northern Eurasian populations (Altaian Kazakhs, Altaians-Kizhi, Teleuts, Khakassians, Shorians, Tyvans, Todjins, Tofalars, Sojots, Buryats, Khamnigans, Evenks, Mongols, Kalmyks, Tajiks, Kurds, Persians, and Russians; the total sample size was 1437 people). The highest frequency of haplotypes from the cluster of the Genghis Khan's descendants was found in Mongols (34.8%). In Russia, this cluster was found in Altaian Kazakhs (8.3%), Altaians (3.4%), Buryats (2.3%), Tyvans (1.9%), and Kalmyks (1.7%). PMID:17486763

  6. 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

  7. 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…

  8. 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,…

  9. 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…

  10. 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…

  11. 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

  12. Offshore Oligo-Miocene volcanic fields within the Corsica-Liguria Basin: Magmatic diversity and slab evolution in the western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Réhault, J.-P.; Honthaas, C.; Guennoc, P.; Bellon, H.; Ruffet, G.; Cotten, J.; Sosson, M.; Maury, R. C.

    2012-07-01

    The European and Corsica-Sardinia margins of the Ligurian Sea (western Mediterranean) have been affected by a geochemically diverse igneous activity, offshore and onshore, since the Eocene. This magmatism occurred in a global subduction-related framework. On the European side, the oldest Tertiary magmatism dated at ca. 35 Ma was mainly calc-alkaline. It included the emplacement of plutonic bodies of adakitic affinity, such as the quartz microdiorite laccolith locally referred to as "esterellite". Younger magmatic events on-land within the whole Ligurian domain were mostly medium-K or K-rich calc-alkaline. Miocene volcanic activity was important in Sardinia, where andesites and ignimbrites were erupted during several magmatic cycles. In Corsica, it was minor although it emplaced lamprophyres near Sisco at 15 Ma. Dredging and diving cruises conducted in the Ligurian Sea during the last thirty years allowed us to collect a number of submarine samples. We discuss here their geochemistry (major and trace elements) and their whole-rock K-Ar ages and mineral 40Ar-39Ar plateau ages. Around 15 Ma, minor amounts of adakitic lavas were emplaced off southwestern Corsica, in the deepest part of the Liguria-Corsica Basin. They rested over the thinnest southwestern Corsica Hercynian continental crust. Closer to the coast, contemporaneous calc-alkaline rocks erupted on a less thinned crust. The adakitic events could be indicative of either the final stages of active subduction, or alternatively of a slab tearing linked to the southeastern retreat and steepening of the slab. The latter event could be connected with the end of the Corsica-Sardinia block drifting and its correlative eastern collision. Younger volcanic effusions, dated at 14-6 Ma, occurred mostly northwest and north of Corsica. K-rich calc-alkaline basalts, shoshonites and K-rich trachytes were emplaced during this period, and alkali basalts erupted as early as 12 Ma in Sardinia. In the Toulon area, alkali basalts

  13. 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

  14. Offshore medicine.

    PubMed

    Baker, D

    2001-03-01

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

  15. Offshore medicine.

    PubMed

    Baker, D

    2001-03-01

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

  16. 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.

  17. 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.

  18. Smarter offshoring.

    PubMed

    Farrell, Diana

    2006-06-01

    During the past 15 years, companies have flocked to a handful of cities in India and Eastern Europe for offshore service functions. As a result, the most popular sites are now overheating: Demand for young professionals is outstripping supply, wages and turnover are soaring, and overburdened infrastructure systems are struggling to serve the explosive growth. The happy news is that the tight labor markets in the well-known hot spots are the exceptions, not the rule. Many attractive alternatives are emerging around the world. According to a McKinsey Global Institute study, more than 90% of the vast and rapidly growing pool of university-educated people suitable for work in multinationals are located outside the current hot spot cities. For instance, Morocco is now home to offshore centers for French and Spanish companies requiring fluent speakers of their home languages. Neighboring Tunisia has used its modern infrastructure, business-friendly regulations, and stable, low-cost workforce to attract companies such as Siemens and Wanadoo. Vietnam offers university graduates who have strong mathematics skills; speak French, English, German, or Russian; and do not demand high wages. The problems facing the hot spots, coupled with the emergence of many more countries able and willing to provide offshore services, mean that picking a site has become more complicated. In choosing a location, companies will have to focus less on low wages and much more on other ways that candidate cities can fulfill their business needs. They will have to be much more rigorous in articulating precisely what they require from an offshore location. That means evaluating their unique needs on a range of dimensions and understanding how alternative locations can meet those needs for the foreseeable future.

  19. 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

  20. The fate of medical knowledge and the neurosciences during the time of Genghis Khan and the Mongolian Empire.

    PubMed

    Safavi-Abbasi, Sam; Brasiliense, Leonardo B C; Workman, Ryan K; Talley, Melanie C; Feiz-Erfan, Iman; Theodore, Nicholas; Spetzler, Robert F; Preul, Mark C

    2007-01-01

    In 25 years, the Mongolian army of Genghis Khan conquered more of the known world than the Roman Empire accomplished in 400 years of conquest. The recent revised view is that Genghis Khan and his descendants brought about "pax Mongolica" by securing trade routes across Eurasia. After the initial shock of destruction by an unknown barbaric tribe, almost every country conquered by the Mongols was transformed by a rise in cultural communication, expanded trade, and advances in civilization. Medicine, including techniques related to surgery and neurological surgery, became one of the many areas of life and culture that the Mongolian Empire influenced.

  1. 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

  2. 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.

  3. The effect of an oil drilling operation on the trace metal concentrations in offshore bottom sediments of the Campos Basin oil field, SE Brazil.

    PubMed

    Rezende, C E; Lacerda, L D; Ovalle, A R C; Souza, C M M; Gobo, A A R; Santos, D O

    2002-07-01

    The concentrations of Al, Fe, Mn, Zn, Cu, Pb, Ni, Cr, Ba, V, Sn and As in offshore bottom sediments from the Bacia de Campos oil field, SE Brazil, were measured at the beginning and at 7 months after completion of the drilling operation. Concentrations of Al, Fe, Ba, Cr, Ni and Zn were significantly higher closer to the drilling site compared to stations far from the site. Average concentrations of Al, Cu, and in particular of Ni, were significantly higher at the end of the drilling operation than at the beginning. Comparison between drilling area sediments with control sediments of the continental platform, however, showed no significant difference in trace metal concentrations. Under the operation conditions of this drilling event, the results show that while changes in some trace metal concentrations do occur during drilling operations, they are not significantly large to be distinguished from natural variability of the local background concentrations.

  4. The effect of an oil drilling operation on the trace metal concentrations in offshore bottom sediments of the Campos Basin oil field, SE Brazil.

    PubMed

    Rezende, C E; Lacerda, L D; Ovalle, A R C; Souza, C M M; Gobo, A A R; Santos, D O

    2002-07-01

    The concentrations of Al, Fe, Mn, Zn, Cu, Pb, Ni, Cr, Ba, V, Sn and As in offshore bottom sediments from the Bacia de Campos oil field, SE Brazil, were measured at the beginning and at 7 months after completion of the drilling operation. Concentrations of Al, Fe, Ba, Cr, Ni and Zn were significantly higher closer to the drilling site compared to stations far from the site. Average concentrations of Al, Cu, and in particular of Ni, were significantly higher at the end of the drilling operation than at the beginning. Comparison between drilling area sediments with control sediments of the continental platform, however, showed no significant difference in trace metal concentrations. Under the operation conditions of this drilling event, the results show that while changes in some trace metal concentrations do occur during drilling operations, they are not significantly large to be distinguished from natural variability of the local background concentrations. PMID:12222892

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  6. 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…

  7. 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...

  8. Increasing transcultural awareness: the McMaster-Aga Khan-CIDA Project workshop model.

    PubMed

    Smith, S E

    1997-01-01

    McMaster-Aga Khan-CIDA Project personnel at McMaster University School of Nursing over a period of four years designed and conducted eight one-day introductory workshops for nurses, faculty, staff, host families, and others involved with Pakistani nurses and Lady Health Visitors studying in Canada. The workshops (entitled Increasing Intercultural Awareness) assisted the Canadian and international participants to improve their awareness and knowledge of transcultural communication in preparation for working and socializing together. Using a participatory and active-learning approach, the workshop method introduced participants to transcultural communication; emphasized appreciation of cultural values, similarities and differences; and provided country-specific information on Pakistan. This article outlines the workshop design and rationale and describes specific examples of the transcultural nursing principles, practices, and teaching activities included in the one-day event. PMID:9369662

  9. 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

  10. Results of recent drilling of specific lowstand systems tracts targets, the implications to future exploration, and the seismic-sequence stratigraphic model Pletmos basin, offshore South Africa

    SciTech Connect

    Keenan, J.H.G. )

    1991-03-01

    The Pletmos basin is a complex series of subbasins off the south coast of South Africa. Depositional styles displayed in the postrift mid-Valanginian to recent sediments reflect the complex interplay of variations in subsidence, sediment supply, eustatic change, and climate. An extensive seismic sequence stratigraphic framework study carried out in 1988 served as the basis for further oil exploration and the evaluation of lowstand systems tracts. Wells were drilled to intersect shelf-margin wedges, basin-floor fans, slope-front fans, prograding lowstand wedges, and incised valley-fill successions depicted by detailed mapping of recent seismic data, integrated with well data. Sequences that apparently resulted from both major and minor downward shift in relative sea level were tested. Although there appears to be adequate sand accumulations on the relict shelf edge in the provenance area, there was little sand in the lowstand target. Seismically, the interpreted lowstand elements are located beyond and below the relict shelf and reflect geometries clearly indicative of component elements of a lowstand systems tract. However, there seems to be some contention about the processes that brought about their deposition. It is important to d toiibe sh between lowstand systems that have been derived by slumping and slope failure, and those that have developed as a result of sediment removal from the shelf and subareal regions during relative sea-level fall. Sand prediction and the relationships between source rock, migration pathways, and reservoir can, therefore, be ascertained with a higher degree of certainty.

  11. 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

  12. 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.

  13. Geologic framework of the offshore region adjacent to Delaware

    USGS Publications Warehouse

    Benson, R.N.; Roberts, J.H.

    1989-01-01

    Several multichannel, common depth point (CDP) seismic reflection profiles concentrated in the area of the entrance to Delaware Bay provide a tie between the known onshore geology of the Coastal Plain of Delaware and the offshore geology of the Baltimore Canyon Trough. The data provide a basis for understanding the geologic framework and petroleum resource potential of the area immediately offshore Delaware. Our research has focused on buried early Mesozoic rift basins and their geologic history. Assuming that the buried basins are analogous to the exposed Newark Supergroup basins of Late Triassic-Early Jurassic age, the most likely possibility for occurrence of hydrocarbon source beds in the area of the landward margin of the Baltimore Canyon Trough is presumed to be lacustrine, organic-rich shales probably present in the basins. Although buried basins mapped offshore Delaware are within reach of drilling, no holes have been drilled to date; therefore, direct knowledge of source, reservoir, and sealing beds is absent. Buried rift basins offshore Delaware show axial trends ranging from NW-SE to NNE-SSW. Seismic reflection profiles are too widely spaced to delineate basin boundaries accurately. Isopleths of two-way travel time representing basin fill suggest that, structurally, the basins are grabens and half-grabens. As shown on seismic reflection profiles, bounding faults of the basins intersect or merge with low-angle fault surfaces that cut the pre-Mesozoic basement. The rift basins appear to have formed by Mesozoic extension that resulted in reverse motion on reactivated basement thrust faults that originated from compressional tectonics during the Paleozoic. Computer-plotted structure contour maps derived from analysis of seismic reflection profiles provide information on the burial history of the rift basins. The postrift unconformity bevels the rift basins and, in the offshore area mapped, ranges from 2000 to 12,000 m below present sea level. The oldest

  14. 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.

  15. Pathways and mechanisms of offshore water intrusions on the Espírito Santo Basin shelf (18°S-22°S, Brazil)

    NASA Astrophysics Data System (ADS)

    Palóczy, A.; Brink, K. H.; da Silveira, Ilson C. A.; Arruda, Wilton Z.; Martins, Renato P.

    2016-07-01

    The pathways and physical mechanisms associated with intrusions of cold, nutrient-rich South Atlantic Central Water (SACW) on the continental shelf of the Espírito Santo Basin (ESB), off southeast Brazil (18°S-22°S), are investigated. To this end, a set of process-oriented, Primitive-Equation (PE) numerical models are used, together with an independent and more complete PE model, available observations and simple theoretical ideas. SACW enters the model ESB shelf mostly through two preferential pathways along the Tubarão Bight (TB, 19.5°S-22°S). These pathways are found to be locations where an equatorward along-isobath pressure gradient force (PGFy*) of O>(10-6 m s-2) develops in response to steady wind forcing. This equatorward PGFy* is essentially in geostrophic balance, inducing onshore flow across the shelf edge, and most of the shelf proper. The Brazil Current (BC) imparts an additional periodic (in the along-shelf direction) PGFy* on the shelf. The intrinsic pycnocline uplifting effect of the BC in making colder water available at the shelf edge is quantified. The BC also induces local intrusions by inertially overshooting the shelf edge, consistent with estimated Rossby numbers of ≈0.3-0.5. In addition, the planetary β-effect is related to a background equatorward PGFy*. A modified Arrested Topographic Wave model is shown to be a plausible rationalization for the shelf-wide spreading of the pressure field imparted by the BC at the shelf edge. The deep-ocean processes examined here are found to enhance the onshore transport of SACW, while wind forcing is found to dominate it at leading order.

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

    PubMed Central

    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

    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

  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. The cytoskeletal regulator Genghis khan is required for columnar target specificity in the Drosophila visual system

    PubMed Central

    Gontang, Allison C.; Hwa, Jennifer J.; Mast, Joshua D.; Schwabe, Tina; Clandinin, Thomas R.

    2011-01-01

    A defining characteristic of neuronal cell type is the growth of axons and dendrites into specific layers and columns of the brain. Although differences in cell surface receptors and adhesion molecules are known to cause differences in synaptic specificity, differences in downstream signaling mechanisms that determine cell type-appropriate targeting patterns are unknown. Using a forward genetic screen in Drosophila, we identify the GTPase effector Genghis khan (Gek) as playing a crucial role in the ability of a subset of photoreceptor (R cell) axons to innervate appropriate target columns. In particular, single-cell mosaic analyses demonstrate that R cell growth cones lacking Gek function grow to the appropriate ganglion, but frequently fail to innervate the correct target column. Further studies reveal that R cell axons lacking the activity of the small GTPase Cdc42 display similar defects, providing evidence that these proteins regulate a common set of processes. Gek is expressed in all R cells, and a detailed structure-function analysis reveals a set of regulatory domains with activities that restrict Gek function to the growth cone. Although Gek does not normally regulate layer-specific targeting, ectopic expression of Gek is sufficient to alter the targeting choices made by another R cell type, the targeting of which is normally Gek independent. Thus, specific regulation of cytoskeletal responses to targeting cues is necessary for cell type-appropriate synaptic specificity. PMID:22007130

  19. Genghis Khan (Gek) as a putative effector for Drosophila Cdc42 and regulator of actin polymerization.

    PubMed

    Luo, L; Lee, T; Tsai, L; Tang, G; Jan, L Y; Jan, Y N

    1997-11-25

    The small GTPases Cdc42 and Rac regulate a variety of biological processes, including actin polymerization, cell proliferation, and JNK/mitogen-activated protein kinase activation, conceivably via distinct effectors. Whereas the effector for mitogen-activated protein kinase activation appears to be p65PAK, the identity of effector(s) for actin polymerization remains unclear. We have found a putative effector for Drosophila Cdc42, Genghis Khan (Gek), which binds to Dcdc42 in a GTP-dependent and effector domain-dependent manner. Gek contains a predicted serine/threonine kinase catalytic domain that is 63% identical to human myotonic dystrophy protein kinase and has protein kinase activities. It also possesses a large coiled-coil domain, a putative phorbol ester binding domain, a pleckstrin homology domain, and a Cdc42 binding consensus sequence that is required for its binding to Dcdc42. To study the in vivo function of gek, we generated mutations in the Drosophila gek locus. Egg chambers homozygous for gek mutations exhibit abnormal accumulation of F-actin and are defective in producing fertilized eggs. These phenotypes can be rescued by a wild-type gek transgene. Our results suggest that this multidomain protein kinase is an effector for the regulation of actin polymerization by Cdc42.

  20. The cytoskeletal regulator Genghis khan is required for columnar target specificity in the Drosophila visual system.

    PubMed

    Gontang, Allison C; Hwa, Jennifer J; Mast, Joshua D; Schwabe, Tina; Clandinin, Thomas R

    2011-11-01

    A defining characteristic of neuronal cell type is the growth of axons and dendrites into specific layers and columns of the brain. Although differences in cell surface receptors and adhesion molecules are known to cause differences in synaptic specificity, differences in downstream signaling mechanisms that determine cell type-appropriate targeting patterns are unknown. Using a forward genetic screen in Drosophila, we identify the GTPase effector Genghis khan (Gek) as playing a crucial role in the ability of a subset of photoreceptor (R cell) axons to innervate appropriate target columns. In particular, single-cell mosaic analyses demonstrate that R cell growth cones lacking Gek function grow to the appropriate ganglion, but frequently fail to innervate the correct target column. Further studies reveal that R cell axons lacking the activity of the small GTPase Cdc42 display similar defects, providing evidence that these proteins regulate a common set of processes. Gek is expressed in all R cells, and a detailed structure-function analysis reveals a set of regulatory domains with activities that restrict Gek function to the growth cone. Although Gek does not normally regulate layer-specific targeting, ectopic expression of Gek is sufficient to alter the targeting choices made by another R cell type, the targeting of which is normally Gek independent. Thus, specific regulation of cytoskeletal responses to targeting cues is necessary for cell type-appropriate synaptic specificity.

  1. 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.

  2. Structural features offshore northern Taiwan

    NASA Astrophysics Data System (ADS)

    Yicheng Yang, Eason; Liu, Char-Shine; Chang, Jih-Hsin; Chiu, Chien-Hsuan

    2016-04-01

    The area offshore northern Taiwan is the place where East China Sea Shelf extends into the Southern Okinawa Trough, and where pre-Pleistocene arc-continental collision had occurred. Comparison between fault distribution in the area with previously published results suggests that the fault distribution and regional structural framework are still controversial. Using marine multichannel seismic reflection data collected in 3 marine geophysical survey cruises, we remapped the fault distribution in the northern offshore area of Taiwan. By analyzing all the seismic profiles using the KINGDOM suite (a seismic interpretation software), a new fault distribution map is presented, and a subsurface unconformity PRSB (Pliocene reflection sequence boundary) is identified. Six major NE-SW trending high-angle normal faults cut the PRSB can be traced to the fault systems on land northernmost Taiwan. These normal faults are located between the Southern Okinawa Trough and the East China Sea continental shelf basin, and have been suggested to be reactivated from pre-existing reverse faults. The offsets of fault ramps in PRSB increase toward southeast. The isopach map of the study area compiled shows that sediment strata overlying PRSB thin toward northwest.

  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.

  4. 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

  5. Servicing the offshore industry

    SciTech Connect

    1997-03-01

    What factors are leading operators to using boat-based services vs. those that are rig-based for offshore completions, stimulations and workovers? What trends are companies experiencing in completion practices for the unconsolidated formations in the Gulf of Mexico? What are companies` most important specifications for well service boats operating near their offshore platforms? To answer these and other questions, Petroleum Engineering International asked those who should know -- the producing companies active in offshore operations in the Gulf of Mexico and worldwide.

  6. 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.

  7. 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.

  8. 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.

  9. Offshore technology has a tremendous future

    SciTech Connect

    Brundage, H.T.

    1984-05-01

    Proven offshore technology has the capability to produce oil and gas through the world's continental shelves, on the continental slopes, and toward the abyssal plains. As with all other economic endeavors, there will eventually be a point of diminishing returns in producing offshore hydrocarbons. But just where or when this point will be reached is not now known, nor is it likely to be known soon. A basic fact of oceanographic research is that oil shows have been found in deep ocean basins, such as at Challenger Knoll in the Sigsbee Deep in the central Gulf of Mexico, and elsewhere. At least 240 billion barrels of recoverable oil are considered to exist in the world's continental shelves. Exploratory drilling combined with engineering and oceanographic research, continually broaden horizons and potential in this respect.

  10. A tribute to Sheik Humarr Khan and all the healthcare workers in West Africa who have sacrificed in the fight against Ebola virus disease: Mae we hush.

    PubMed

    Bausch, Daniel G; Bangura, James; Garry, Robert F; Goba, Augustine; Grant, Donald S; Jacquerioz, Frederique A; McLellan, Susan L; Jalloh, Simbirie; Moses, Lina M; Schieffelin, John S

    2014-11-01

    The Kenema Government Hospital Lassa Fever Ward in Sierra Leone, directed since 2005 by Dr. Sheikh Humarr Khan, is the only medical unit in the world devoted exclusively to patient care and research of a viral hemorrhagic fever. When Ebola virus disease unexpectedly appeared in West Africa in late 2013 and eventually spread to Kenema, Khan and his fellow healthcare workers remained at their posts, providing care to patients with this devastating illness. Khan and the chief nurse, Mbalu Fonnie, became infected and died at the end of July, a fate that they have sadly shared with more than ten other healthcare workers in Kenema and hundreds across the region. This article pays tribute to Sheik Humarr Khan, Mbalu Fonnie and all the healthcare workers who have acquired Ebola virus disease while fighting the epidemic in West Africa. Besides the emotional losses, the death of so many skilled and experienced healthcare workers will severely impair health care and research in affected regions, which can only be restored through dedicated, long-term programs. PMID:25196533

  11. A tribute to Sheik Humarr Khan and all the healthcare workers in West Africa who have sacrificed in the fight against Ebola virus disease: Mae we hush.

    PubMed

    Bausch, Daniel G; Bangura, James; Garry, Robert F; Goba, Augustine; Grant, Donald S; Jacquerioz, Frederique A; McLellan, Susan L; Jalloh, Simbirie; Moses, Lina M; Schieffelin, John S

    2014-11-01

    The Kenema Government Hospital Lassa Fever Ward in Sierra Leone, directed since 2005 by Dr. Sheikh Humarr Khan, is the only medical unit in the world devoted exclusively to patient care and research of a viral hemorrhagic fever. When Ebola virus disease unexpectedly appeared in West Africa in late 2013 and eventually spread to Kenema, Khan and his fellow healthcare workers remained at their posts, providing care to patients with this devastating illness. Khan and the chief nurse, Mbalu Fonnie, became infected and died at the end of July, a fate that they have sadly shared with more than ten other healthcare workers in Kenema and hundreds across the region. This article pays tribute to Sheik Humarr Khan, Mbalu Fonnie and all the healthcare workers who have acquired Ebola virus disease while fighting the epidemic in West Africa. Besides the emotional losses, the death of so many skilled and experienced healthcare workers will severely impair health care and research in affected regions, which can only be restored through dedicated, long-term programs.

  12. 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

  13. Getting offshoring right.

    PubMed

    Aron, Ravi; Singh, Jitendra V

    2005-12-01

    The prospect of offshoring and outsourcing business processes has captured the imagination of CEOs everywhere. In the past five years, a rising number of companies in North America and Europe have experimented with this strategy, hoping to reduce costs and gain strategic advantage. But many businesses have had mixed results. According to several studies, half the organizations that have shifted processes offshore have failed to generate the expected financial benefits. What's more, many of them have faced employee resistance and consumer dissatisfaction. Clearly, companies have to rethink how they formulate their offshoring strategies. A three-part methodology can help. First, companies need to prioritize their processes, ranking each based on two criteria: the value it creates for customers and the degree to which the company can capture some of that value. Companies will want to keep their core (highest-priority) processes in-house and consider outsourcing their commodity (low-priority) processes; critical (moderate-priority) processes are up for debate and must be considered carefully. Second, businesses should analyze all the risks that accompany offshoring and look systematically at their critical and commodity processes in terms of operational risk (the risk that processes won't operate smoothly after being offshored) and structural risk (the risk that relationships with service providers may not work as expected). Finally, companies should determine possible locations for their offshore efforts, as well as the organizational forms--such as captive centers and joint ventures--that those efforts might take. They can do so by examining each process's operational and structural risks side by side. This article outlines the tools that will help companies choose the right processes to offshore. It also describes a new organizational structure called the extended organization, in which companies specify the quality of services they want and work alongside providers

  14. 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

  15. 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.

  16. Indoor radon monitoring near an in situ leach mining site in D G Khan, Pakistan.

    PubMed

    Matiullah; Malik, Fariha; Rafique, Muhammad

    2012-12-01

    Indoor radon and its decay products are considered to be the second leading cause of lung cancer after cigarette smoking. This is why extensive radon surveys have been carried out in many countries of the world, including Pakistan. In this context, 25 spots were selected at workplaces in the vicinity of the uranium mining site in Dera Ghazi Khan District for indoor radon measurement. For this purpose, CR-39 based radon detectors were installed at head height and were exposed to indoor radon for 60 days. After retrieval, these detectors were etched in a 6 M solution of NaOH at the temperature of 80 °C for 16 h in order to make the alpha particle tracks visible. The observed track densities were related to the indoor radon concentration using a calibration factor of 2.7 tracks cm(-2) h(-1)/kBq m(-3). The measured indoor radon concentration ranged from ∼386 ±161 to 3028 ± 57 Bq m(-3) with an average value of 1508 ± 81 Bq m(-3) in the studied areas of Dera Ghazi Khan District. The mean annual effective dose ranged from 2.22 ± 0.93 to 17.44 ± 0.33 mSv yr(-1), with an average of 8.68 ± 0.47 mSv yr(-1). The effect of the seasonal correction factor (SCF) on the annual average radon concentration has also been considered. Results of the current study show that, for the majority of the workplaces studied, indoor radon levels exceed the action levels proposed by many world organisations.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. The state of offshore

    SciTech Connect

    Nelson, B.F.

    1991-01-01

    In this book, the author explains the factors behind state involvement in offshore petroleum activities. From his analysis of government workings in Great Britain and Norway, he concludes that state intervention is determined by complex interactions among government officials, economic interests, and environmental pressures.

  3. 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)

  4. 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.

  5. 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.

  6. Offshore Space Center (offshore launch site)

    NASA Astrophysics Data System (ADS)

    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.

  7. 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.

  8. 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.

  9. 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.

  10. The Y-chromosome C3* star-cluster attributed to Genghis Khan's descendants is present at high frequency in the Kerey clan from Kazakhstan.

    PubMed

    Abilev, Serikbai; Malyarchuk, Boris; Derenko, Miroslava; Wozniak, Marcin; Grzybowski, Tomasz; Zakharov, Ilya

    2012-02-01

    To verify the possibility that the Y-chromosome C3* star-cluster attributed to Genghis Khan and his patrilineal descendants is relatively frequent in the Kereys, who are the dominant clan in Kazakhstan and in Central Asia as a whole, polymorphism of the Y-chromosome was studied in Kazakhs, represented mostly by members of the Kerey clan. The Kereys showed the highest frequency (76.5%) of individuals carrying the Y-chromosome variant known as C3* star-cluster ascribed to the descendants of Genghis Khan. C3* star-cluster haplotypes were found in two subclans, Abakh-Kereys and Ashmaily-Kereys, diverged about 20-22 generations ago according to the historical data. Median network of the Kerey star-cluster haplotypes at 17 STR loci displays a bipartite structure, with two subclusters defined by the only difference at the DYS448 locus. Noteworthy is a strong correspondence of these subclusters with the Kerey subclans affiliation. The data obtained suggest that the Kerey clan appears to be the largest known clan in the world descending from a common Y-chromosome ancestor. Possible ways of Genghis Khan's relationship to the Kereys are discussed.

  11. Pesticides in shallow groundwater of Bahawalnagar, Muzafargarh, D.G. Khan and Rajan Pur districts of Punjab, Pakistan.

    PubMed

    Tariq, Muhammad Ilyas; Afzal, Shahzad; Hussain, Ishtiaq

    2004-06-01

    In Pakistan there is little data on environmental contamination of rural water sources by pesticides. This study evaluated pesticide contamination of groundwater in four intensive cotton growing districts. Water samples were collected from 37 rural open wells in the areas of Bahwalnagar, Muzafargarh, D.G. Khan and Rajan Pur districts of Punjab and analysed for eight pesticides which are mostly used. Information on types of pesticide used and distance to nearest pesticide mixing area and application areas was obtained for each site. From the eight pesticides analysed, six pesticides were detected in the water samples. Only cypermethrin and cabosulfan were not detected. The percentage of detection of bifenthrin, lambda-cyhalothrin, carbofuran, endosulfan, methyl parathion and monocrotophos was, respectively 13.5%, 5.4%, 59.4%, 8%, 5.4% and 35.1% in July; 16.2%, 13.55%, 43.2%, 8%, N.D. (not detected) and 24.3% in October. Maximum contamination levels (MCLs) established by the U.S. Environmental Protection Agency for drinking water were not exceeded. The study has shown the need for monitoring pesticide contamination in rural water resources, and the development of drinking water quality standards for specific pesticides in Pakistan. The conclusions and recommendations will be disseminated to senior decision makers in central and local governments, extension agents and farmers.

  12. 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.

  13. 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.

  14. 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.

  15. Offshore gas liquefaction without offshore LNG plants

    SciTech Connect

    Haines, G.H.; Thompson, J.

    1980-02-18

    Constructors John Brown Ltd.'s Cold Box Shuttle liquefaction system offers an economical means of recovering offshore gas by eliminating the need for platform liquefaction facilities and by producing onshore the bulk of the cold for LNG refrigeration. Under the C.B.S. concept, a ship provided with heat-exchange equipment conveys liquid nitrogen from a shore terminal out to the platform, where the ship is attached to a single-point mooring (SPM). Heat exchange between the liquid nitrogen and the gas from the platform produces LNG for transport back to port in the same ship. At the port terminal, the cold in LNG can help generate the power needed in the liquid-nitrogen plant. The production efficiency of the C.B.S. system depends upon the gas production rate, the number and size of LNG vessels served by the shore terminal, the limiting wave heights for mooring and loading, the journey time, the mooring time, the planned maintenance of SPM, and the unplanned downtime of the SPM.

  16. 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.

  17. 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.

  18. 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.

  19. Advanced offshore oil platforms

    SciTech Connect

    Ellers, F.S.

    1982-04-01

    Four innovative offshore platforms that are designed to withstand 100-foot waves in waters 600-feet deep are described. These platforms are: (1) Stratfjord B Concrete Gravity-Base Platform; (2) Magnus Steel-Template-Jacket Platform; (3) Hutton Tension-Leg Platform; and (4) Block 280 Guyed Tower. The Statfjord B platform, designed in Norway, rests on four massive concrete columns with storage tanks at the base. It depends solely on its own mass for stability. The Magnus platform, designed by the British, is the heaviest offshore platform yet fabricated, weighing 41,000 tons. Two of the platform's four legs will incorporate flotation chambers so that the structure can be floated to its site in the North Sea. The Hutton structure, also designed in England, will consist of a buoyant hull tethered to the sea floor by slender steel tubes at its four corners. The first platform of its type, the Hutton structure is also destined for the North Sea. The US designed Block 280 guyed tower is designed for service in the Gulf of Mexico in water 1000 feet deep. It will be pinned to the sea floor by a spokelike array of 20 steel cables, each one more than 3000 feet long. The tower and its guys will weigh 43,000 tons, slightly more than the Magnus steel-template jacket and more than four time as much as the Eiffel Tower. At a cost of approximately $2.6 billion, the Magnus is the most expensive offshore platform to date. The Statfjord B was put into production in 1982. The Magnus is scheduled for oil production in 1983. The Hutton and the Block 280 will both be producing in 1984. (JMT)

  20. 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

  1. Buckling of offshore structures

    SciTech Connect

    Walker, A.C.; Ellinas, C.P.; Supple, W.J.

    1984-01-01

    This new handbook gives detailed design guidance for a wide range of structural components and types of loading related to the buckling of offshore structures. It presents many hundreds of test results that have been examined and collated to give a common base of comparison, and its surveys all the relevant national and international design codes, comparing the relative accuracy of their predictions against the available test results. Contents are: unstiffened cord and bracing elements; ring-stiffened cylinders; stringer-stiffened and orthogonally-stiffened cylinders; flat panels; and end-closures and transition shells.

  2. Offshore abandonment heats up

    SciTech Connect

    1995-08-01

    This paper reviews the new concerns regarding the decommissioning of offshore oil platforms which are rapidly coming of age. It reviews the history of past removal operations and the public outcry which is now causing a reevaluation of this abandonment policy. It reviews the number of platforms which are rapidly approaching maturity on a global basis. It then goes on to costs involved in such removal operations. Finally, it reviews the new platform designs which should allow a much more cost effective decommissioning process for these future rigs.

  3. Offshore Fish Community: Ecological Interactions

    EPA Science Inventory

    The offshore (>80 m) fish community of Lake Superior is made up of predominately native species. The most prominent species are deepwater sculpin, kiyi, cisco, siscowet lake trout, burbot, and the exotic sea lamprey. Bloater and shortjaw cisco are also found in the offshore zone...

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Bahrain's offshore banking center

    SciTech Connect

    Gerakis, A.S.; Roncesvalles, O.

    1983-01-01

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

  9. Mobile offshore drilling units for frontier areas

    SciTech Connect

    Kelly, P.L.

    1983-04-01

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

  10. Observations of gas hydrates in marine sediments, offshore northern California

    USGS Publications Warehouse

    Brooks, J.M.; Field, M.E.; Kennicutt, M.C.

    1991-01-01

    Biogenic gas hydrates were recovered in shallow cores (< 6 m deep) from the Eel River basin in offshore northern California between 40??38??? and 40??56???N. The gas hydrates contained primarily methane (??13C = -57.6 to -69.1???) and occurred as dispersed crystals, small (2-20 mm) nodules, and layered bands within the sediment. These hydrates, recovered in sediment at water depths between 510 and 642 m, coincide nearly, but not exactly, with areas showing bottom-simulating reflectors (BSRs) on seismic-reflection records. This study confirms indirect geophysical and geologic observations that gas hydrates are present north of the Mendocino Fracture Zone in sediment of the Eel River basin but probably are absent to the south in the Point Arena basin. This discovery extends the confirmed sites of gas hydrates in the eastern Pacific region beyond the Peruvian and Central American margins to the northern California margin. ?? 1991.

  11. 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.

  12. Offshore pipeline failures. Master's thesis

    SciTech Connect

    Woodson, R.D.

    1990-12-01

    An overview of current concerns in the regulation of offshore pipelines is presented along with tabulated summaries of pipeline failure causes, failure prevention techniques, and pipeline monitoring and early intervention techniques. A database of over 1000 offshore pipeline failures in the Gulf of Mexico Offshore waters has been compiled from combined records of the Department of Transportation Office of pipeline Safety, U.S. Coast Guard National Response Center, and the Department of Interior Minerals Management Service. The data has been analyzed to identify trends and initial recommendations for future data collection have been suggested.

  13. Quantifying the Benefits of Combining Offshore Wind and Wave Energy

    NASA Astrophysics Data System (ADS)

    Stoutenburg, E.; Jacobson, M. Z.

    2009-12-01

    For many locations the offshore wind resource and the wave energy resource are collocated, which suggests a natural synergy if both technologies are combined into one offshore marine renewable energy plant. Initial meteorological assessments of the western coast of the United States suggest only a weak correlation in power levels of wind and wave energy at any given hour associated with the large ocean basin wave dynamics and storm systems of the North Pacific. This finding indicates that combining the two power sources could reduce the variability in electric power output from a combined wind and wave offshore plant. A combined plant is modeled with offshore wind turbines and Pelamis wave energy converters with wind and wave data from meteorological buoys operated by the US National Buoy Data Center off the coast of California, Oregon, and Washington. This study will present results of quantifying the benefits of combining wind and wave energy for the electrical power system to facilitate increased renewable energy penetration to support reductions in greenhouse gas emissions, and air and water pollution associated with conventional fossil fuel power plants.

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

    USGS Publications Warehouse

    Coleman, James L.; 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.

  15. 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…

  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. 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.

  18. Offshore well support miniplatform

    SciTech Connect

    Blandford, J.W.

    1987-07-14

    This patent describes a protective well support system installed on an offshore well having an upstanding conductor pipe extending above the seabed, the system comprising: (a) an upstanding conductor clamp (adapts to encircle the conductor pipe) formed by two upstanding facing members supported by a bottom engaging frame; (b) the frame including frame members joined together defining a substantially horizontal rectangular support frame for engaging the seabed; (c) angularly extending brace members secured at one end to the conductor clamp and at the other end to the frame; (d) the conductor clamp attaches to the frame and extending upright to enable the conductor clamp to fasten about the conductor pipe; (e) a boat landing mounts about the conductor pipe, the boat landing formed by at least two sectional components fixedly secured to semicircular clamp members adapted to encircle the conductor pipe for mounting the boat landing components; and (f) well platform means supported on bracket means adapted to encircle the conductor pipe for removably securing the well platform means.

  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. 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.

  1. Spring sapping on the lower continental slope, offshore New Jersey

    USGS Publications Warehouse

    Robb, James M.

    1984-01-01

    Undersea discharge of ground water during periods of lower sea level may have eroded valleys on part of the lower continental slope, offshore New Jersey. Steep-headed basins, cliffed and terraced walls, and irregular courses of these valleys may have been produced by sapping of exposed near-horizontal Tertiary strata. Joints in Eocene calcareous rocks would have localized ground-water movement. Some karstlike features of the submarine topography and the outcrops suggest that solution of the calcareous rocks also took place.

  2. 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.

  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. 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.

  5. 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

  6. High-resolution imagery of active faulting offshore Al Hoceima, Northern Morocco

    NASA Astrophysics Data System (ADS)

    d'Acremont, E.; Gutscher, M.-A.; Rabaute, A.; Mercier de Lépinay, B.; Lafosse, M.; Poort, J.; Ammar, A.; Tahayt, A.; Le Roy, P.; Smit, J.; Do Couto, D.; Cancouët, R.; Prunier, C.; Ercilla, G.; Gorini, C.

    2014-09-01

    Two recent destructive earthquakes in 1994 and 2004 near Al Hoceima highlight that the northern Moroccan margin is one of the most seismically active regions of the Western Mediterranean area. Despite onshore geodetic, seismological and tectonic field studies, the onshore-offshore location and extent of the main active faults remain poorly constrained. Offshore Al Hoceima, high-resolution seismic reflection and swath-bathymetry have been recently acquired during the Marlboro-2 cruise. These data at shallow water depth, close to the coast, allow us to describe the location, continuity and geometry of three active faults bounding the offshore Nekor basin. The well-expressed normal-left-lateral onshore Trougout fault can be followed offshore during several kilometers with a N171°E ± 3° trend. Westward, the Bousekkour-Aghbal normal-left-lateral onshore fault is expressed offshore with a N020°E ± 4° trending fault. The N030°E ± 2° Bokkoya fault corresponds to the western boundary of the Plio-Quaternary offshore Nekor basin in the Al Hoceima bay and seems to define an en échelon tectonic pattern with the Bousekkour-Aghbal fault. We propose that these three faults are part of the complex transtensional system between the Nekor fault and the Al-Idrissi fault zone. Our characterization of the offshore expression of active faulting in the Al Hoceima region is consistent with the geometry and nature of the active fault planes deduced from onshore geomorphological and morphotectonic analyses, as well as seismological, geodetic and geodynamic data.

  7. Offshore fares well in energy storm

    SciTech Connect

    Ball, E.R.

    1982-05-01

    The effects of the worldwide economic slowdown on the energy industry in general, and offshore petroleum production activity, in particular is discussed. The world crude oil supply is reviewed, and the effects of the petroleum glut are evaluated for onshore and offshore activity. Offshore drilling has fared better than most of the other energy industry sectors, primarily because major operators, worldwide, still view the offshore as the prime province for large oil discoveries, particularly in the United States. (JMT)

  8. 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.

  9. Numerical and experimental analysis of a retrievable offshore loading facility

    SciTech Connect

    Sterndorff, M.J.; O`Brien, P.

    1995-12-31

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

  10. 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.

  11. Proceedings of Offshore Europe 91

    SciTech Connect

    Not Available

    1991-01-01

    All papers in this volume were presented at Offshore Europe held in Aberdeen, Scotland, September 3--6, 1991. Included are the following papers: Low-damage-fluid-loss control for well completions; Isolation techniques for subsea gas pipelines; New water injection technology.

  12. 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

  13. 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.

  14. Transfer terminal for offshore production

    SciTech Connect

    Arnaudeau, M.

    1983-02-01

    A mooring station and transfer terminal for offshore hydrocarbon production is provided, comprising a coaxial riser linking underwater production and safety manifolds to surface lines. An underwater connector and quick release means are provided to facilitate rapid connection and disconnection of the riser pipes.

  15. 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.

  16. Ubarana Oil Field, offshore Brazil: case history

    SciTech Connect

    Chagas, L.S.; Stringhini, A.V.; Gontijo, J.E.

    1981-05-01

    Ubarana is the first commercial oil field on the northern continental shelf of Brazil. Discovery well No. 1-RNS-3, drilled in 1973, was located on a seismic structural high in the offshore extension of the Potiguar Basin, about 13 km from the coast and 160 km northwest of Natal. The well penetrated oil-bearing, fluvio-deltaic sandstones of the Cretaceous acu formation. Five outpost wells, also located on the mapping of seismic horizons adjacent to the producing interval, helped to extend the limits of the accumulation. A total of 1.4 million cu m of oil has been produced between 1976 and Oct. 1980. The surface area of Ubarana Field is approximately 35 sq km with oil-bearing reservoirs at an average depth of approximately 2400 m. Permeability and porosity of the sandstones generally are poor. Pressure is normal and the main production mechanism is solution gas drive. The volume of oil in place is approximately 37 million cu m; estimated recovery factor is 29%. There are presently 4 platforms in the Ubarana Field active in drilling and production with 32 producing wells, and 14 locations to be drilled.

  17. Climate modulated erosion and sediment flux control offshore crustal structure at South China Sea continental margin

    NASA Astrophysics Data System (ADS)

    Clift, P. D.; Brune, S.; Quinteros, J.

    2015-12-01

    Rifted continental lithosphere subsides as a consequence of combined crustal thinning and mantle lithosphere cooling yet basins on some continental margins experience anomalous subsidence events that postdate active extension. Deep basins on the northern margin of the South China Sea, notably the Baiyun Sag, show basement subsidence accelerating after ~21 Ma, postdating extension by several million years. Similar subsidence events are seen after 5 Ma in the Song Hong Basin and after 11 Ma in the Qiongdongnan Basin. We combine geophysical observations and numerical forward modeling to show that loading of the offshore basins by increased sediment flux caused by faster onshore erosion following Early Miocene monsoon intensification is a viable trigger for ductile flow after the cessation of active extension. Loading works in conjunction with onshore uplift to drive flow of the lower crust away from the rift axis. As well as sediment supply rates distribution patterns and drainage capture can be significant in controlling crustal flow and thinning. This illustrates that offshore basin dynamics at continental margins with weak crust can be controlled by onshore surface processes in a newly recognized form of climate-tectonic coupling.

  18. 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.

  19. 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

  20. Water resources and related geology of Dera Ismail Khan district, West Pakistan, with reference to the availability of ground water for development

    USGS Publications Warehouse

    Hood, J.W.; Khan, Lutfe Ali; Jawaid, Khalid

    1970-01-01

    Dera Ismail (D.I.) Khan District contains an area of 3,450 square miles between the right bank of the Indus River and the Sulaiman Range in westcentral West Pakistan. Agriculture is the principal source of income in the District, but only a small part of the arable land is fully utilized. The region is semiarid and has an average annual rainfall of about 9 inches and a potential evapotranspirational rate of eight to nine times the annual rainfall. Thus, rainfall alone is not adequate for high-intensity cropping. Irrigation is practiced near the Indus River; the Paharpur Canal is used, as well as the traditional inundation method. Elsewhere in the District, adequate water is supplied to local areas by karezes, perennial streams from the mountains, and some recently installed tubewells (see 'Glossary'). Further development of ground-water supplies would permit a more effective utilization of most of the presently tilled land and would allow additional land to be farmed. D.I. Khan District is primarily an alluvial plain that slopes from the mountain ranges in the northern and western parts of the District toward the Indus River. Rocks in the bordering mountains are of Paleozoic to early or middle Pleistocene age. The unconsolidated rocks of the plain, of middle (?) Pleistocene to Holocene (Recent) age, consist of piedmont deposits derived from the hills to the north and west and of alluvium laid down by the Indus River. These deposits interfinger in a transitional zone about 8 to 12 miles west of the river. Lithologic and structural features indicate that the unconsolidated rocks possibly may be divided into broad units. The investigations in D.I. Khan District have revealed two main areas of potential ground-water development based on considerations of both permeability and chemical quality of the ground water: 1. A belt about 10 miles wide parallels the Indus River from the Khisor Range southward to the area immediately south of D.I. Khan town. In this belt, the

  1. 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.

  2. 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.

  3. 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

  4. Classification of offshore mass movements

    SciTech Connect

    Mulder, T. |; Cochonat, P.

    1996-01-01

    More than 100 offshore mass-movement deposits have been studied in Holocene and Pleistocene sediments. The processes can be divided into three main types: slides/slumps, plastic flows, and turbidity currents, of which 13 main varieties have been recognized. The three types are differentiated mainly by motion, architecture, and shape of failure surface. For slides, the morphology of deposits can usually be linked to a process, but for plastic flows and turbidity currents, information about the motion is mainly provided by the sedimentary record. A static classification based on these features is given, and is related to a dynamic classification system to try to underline the morphological transformation of an offshore event from initiation to deposition.

  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. 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.

  7. 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.

  8. A primer of offshore operations

    SciTech Connect

    Not Available

    1985-01-01

    This book is written in simple language. It gives information about offshore oil and gas operations by not only describing the operations, but also telling why they are necessary. Techniques and equipment utilized the world over are covered in the colorfully illustrated text, and both English and metric measurements are used. The text includes chapters on exploration, drilling, production and workover, and oil and gas transportation.

  9. 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.

  10. 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

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  13. Petroleum geology of the mid-Atlantic continental margin, offshore Virginia

    USGS Publications Warehouse

    Bayer, K.C.; Milici, R.C.

    1989-01-01

    The Baltimore Canyon Trough, a major sedimentary basin on the Atlantic continental shelf, contains up to 18 km of Mesozoic and Cenozoic strata. The basin has been studied extensively by multichannel common depth point (CDP) seismic reflection profiles and has been tested by drilling for hydrocarbon resources in several places. The Mesozoic and Cenozoic strata contained in the basin were deposited in littoral to bathyal depositional settings and contain immature to marginally mature oil-prone and gas-prone kerogen. The more deeply buried strata of Early Mesozoic age are more likely to be thermally mature than are the younger strata with respect to hydrocarbon generation, but contain terrestrially derived coaly organic matter that would be prone to yield gas, rather than oil. An analysis of available CDP seismic reflection data has indicated that there are several potential hydrocarbon plays in the area offshore of Virginia. These include: (1) Lower Mesozoic synrift basins that appear similar to those exposed in the Appalachian Piedmont, (2) a stratigraphic updip pinchout of strata of Early Mesozoic age in the offshore region near the coast, (3) a deeply buried paleoshelf edge, where seismic reflectors dip sharply seaward; and (4) a Cretaceous/Jurassic shelf edge beneath the present continental rise. Of these, the synrift basins and Cretaceous/Jurassic shelf edge are considered to be the best targets for exploration. ?? 1989.

  14. 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.

  15. Vessel movement influences offshore communications system design

    SciTech Connect

    Holcomb, S.R.; Burger, S.D.

    1996-05-27

    Communications links for the Liuhua 11-1 oil production project, offshore China, required a system that would function with vessel movement under typhoon conditions of heavy rainfall and extreme wave action. The system includes a microwave path between two floating production facilities and a satellite connection between the offshore facilities and onshore China. The system provides multiple local-area-network (LAN) linkages, and voice with fax in English and Chinese. The satellite link has a geostabilized platform offshore and a China National Offshore Oil Corp. master earth station onshore. System operations started in mid-1995. This paper reviews the design and performance of this communications network.

  16. 1991 worldwide offshore contractors and equipment directory

    SciTech Connect

    Not Available

    1991-01-01

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

  17. 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.

  18. 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

  19. 78 FR 18618 - National Offshore Safety Advisory Committee; Vacancies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-27

    ... offshore drilling; (c) One member representing companies, organizations, enterprises or similar entities... 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...

  20. 76 FR 39410 - National Offshore Safety Advisory Committee; Vacancies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... specializing in offshore drilling; and, (e) One member representing companies engaged in production of... SECURITY Coast Guard National Offshore Safety Advisory Committee; Vacancies AGENCY: Coast Guard, DHS... National Offshore Safety Advisory Committee. This Committee advises the Secretary of Department of...

  1. 76 FR 11503 - National Offshore Safety Advisory Committee; Vacancies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-02

    ... environmental interests; and, (e) One person representing enterprises specializing in offshore drilling. To be... SECURITY Coast Guard National Offshore Safety Advisory Committee; Vacancies AGENCY: Coast Guard, DHS... National Offshore Safety Advisory Committee. This Committee advises the Coast Guard on matters...

  2. 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.

  3. 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.

  4. 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.…

  5. Seismic expressions of Monterey Formation diagenesis: examples from offshore California

    SciTech Connect

    Roy, M.B.

    1988-03-01

    Diagenesis of the diatomaceous rocks in the Monterey Formation in California coastal and offshore basins involves changes from amorphous biogenic silica to a stable crystalline quartz facies. In the intermediate stage, the transformation undergoes passage from the Opal-A to the Opal-CT phase. Associated with this diagenetic process is a marked increase in bulk densities between the different silica phases, owing to loss of porosity from compaction and solution recrystallization caused by increase in burial load and other physical factors. The sharp density contrast between the silica phases is manifested by an acoustic impedance boundary that may be expressed on seismic records. This seismic event can be distinct and independent of structural configuration, and in many places cuts through stratigraphic boundaries. Several examples of seismic records from offshore California demonstrate the diagenetically caused reflection cutting through Monterey and post-Monterey formations. Current and future exploration efforts in offshore California will continue to center on the widespread Monterey Formation. In addition to being the main source rock, the Monterey is also the reservoir rock. Recent discoveries indicate that oil production is mainly from the highly permeable, fractured, silica-rich sections. It is therefore important to recognize the diagenetic boundaries on seismic records and to delineate the more brittle quartz-rich facies where the reservoir quality is expected to be better than the intermediate Opal-A or Opal-CT facies. Furthermore, these boundaries could also provide good diagenetic traps off the flanks of structures where updip unaltered impermeable rocks hinder fluid migration.

  6. [Offshore ecosystem health status assessment: a review].

    PubMed

    Dai, Ben-lin; Hua, Zu-lin; Mu, Fei-hu; Xu, Ning; He, Yu-long

    2013-04-01

    With the promotion of the concept of sustainable development, the issues of aquatic ecosystem health attract substantial attention, and considerable work has been carried out on the health assessment of waters, e. g. , rivers and lakes. However, the health assessment of offshore ecosystem is still at its exploratory stage. Based on the investigations on the related references at home and abroad, this paper analyzed the concepts of offshore ecosystem health assessment, summarized the main methods for the assessment, the principles for screening related indicators, and the research philosophy, and systematically listed the quantitative indices for the assessment. Aiming at the main existing issues in the researches of offshore ecosystem health, the future research directions about the offshore ecosystem health were suggested. It was considered that the concept and connotation analyses, the screening of assessment indicators, the choice of assessment scale, and the integration of assessment methods should be further strengthened to improve the assessment of offshore ecosystem health.

  7. Offshore Wind Market and Economic Analysis

    SciTech Connect

    Hamilton, Bruce Duncan

    2014-08-27

    This report is the third annual assessment of the U.S. offshore wind market. It includes the following major sections: Section 1: key data on developments in the offshore wind technology sector and the global development of offshore wind projects, with a particular focus on progress in the United States; Section 2: analysis of policy developments at the federal and state levels that have been effective in advancing offshore wind deployment in the United States; Section 3: analysis of actual and projected economic impact, including regional development and job creation; Section 4: analysis of developments in relevant sectors of the economy with the potential to affect offshore wind deployment in the United States

  8. Underbalanced drilling benefits now available offshore

    SciTech Connect

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

    1997-05-01

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

  9. California State Waters Map Series: offshore of Refugio Beach, California

    USGS Publications Warehouse

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

    2015-01-01

    Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft, unconsolidated sediment interspersed with isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Offshore of Refugio Beach map area are directly related to its Quaternary geologic history, geomorphology, and active sedimentary processes. These potential habitats, which lie primarily within the Shelf (continental shelf) but also partly within the Flank (basin flank or continental slope) megahabitats, primarily are composed of soft sediment interrupted by a few carbonate mounds. This homogeneous seafloor of sediment and low-relief bedrock provides promising habitat for groundfish, crabs, shrimp, and other marine benthic organisms.

  10. Comparative management of offshore posidonia residues: composting vs. energy recovery.

    PubMed

    Cocozza, Claudio; Parente, Angelo; Zaccone, Claudio; Mininni, Carlo; Santamaria, Pietro; Miano, Teodoro

    2011-01-01

    Residues of the marine plant posidonia (Posidonia oceanica, PO) beached in tourist zones represent a great environmental, economical, social and hygienic problem in the Mediterranean Basin, in general, and in the Apulia Region in particular, because of the great disturb to the bathers and population, and the high costs that the administrations have to bear for their removal and disposal. In the present paper, Authors determined the heating values of leaves and fibres of PO, the main offshore residues found on beaches, and, meantime, composted those residues with mowing and olive pruning wood. The final composts were characterized for pH, electrical conductivity, elemental composition, dynamic respiration index, phytotoxicity, fluorescence and infrared spectroscopic fingerprints. The aim of the paper was to investigate the composting and energy recovery of PO leaves and fibres in order to suggest alternative solutions to the landfill when offshore residues have to be removed from recreational beaches. The fibrous portion of PO residues showed heating values close to those of other biofuels, thus suggesting a possible utilization as source of energy. At the same time, compost obtained from both PO wastes showed high quality features on condition that the electrical conductivity and Na content are lowered by a correct management of wetting during the composting. PMID:20888211

  11. Comparative management of offshore posidonia residues: composting vs. energy recovery.

    PubMed

    Cocozza, Claudio; Parente, Angelo; Zaccone, Claudio; Mininni, Carlo; Santamaria, Pietro; Miano, Teodoro

    2011-01-01

    Residues of the marine plant posidonia (Posidonia oceanica, PO) beached in tourist zones represent a great environmental, economical, social and hygienic problem in the Mediterranean Basin, in general, and in the Apulia Region in particular, because of the great disturb to the bathers and population, and the high costs that the administrations have to bear for their removal and disposal. In the present paper, Authors determined the heating values of leaves and fibres of PO, the main offshore residues found on beaches, and, meantime, composted those residues with mowing and olive pruning wood. The final composts were characterized for pH, electrical conductivity, elemental composition, dynamic respiration index, phytotoxicity, fluorescence and infrared spectroscopic fingerprints. The aim of the paper was to investigate the composting and energy recovery of PO leaves and fibres in order to suggest alternative solutions to the landfill when offshore residues have to be removed from recreational beaches. The fibrous portion of PO residues showed heating values close to those of other biofuels, thus suggesting a possible utilization as source of energy. At the same time, compost obtained from both PO wastes showed high quality features on condition that the electrical conductivity and Na content are lowered by a correct management of wetting during the composting.

  12. Drilling optimization in deepwater field development offshore Brazil

    SciTech Connect

    Awad, S.P.; Piazza, M.R.; Nogueira, E.F.

    1995-12-31

    Giant deepwater oilfields had been discovered in Campos Basin, offshore Brazil, through the eighties. After overcoming initial problems while drilling the exploratory wells, appraisal wells were drilled under regular performance standards, comparing to shallow water previous data. At that time, Albacora and Marlim field development plans were considering improved performances to occur due to the expected learning effects. The combination of the simultaneous use of dynamic positioned and deep anchored rigs with the technical improvements in well operations resulted in an outstanding overall drilling performance for the development campaign of those fields. The drilling program was concluded well ahead of schedule, establishing guidelines for future deepwater field exploitation. This paper describes Petrobras experience of planning and drilling deepwater development wells, showing the principal measures and factors that led to an update of the company`s operational standards. Also, the ultra deepwater drilling R and D projects carried out at the moment are briefly introduced, being their aims to keep or even improve the company`s performance and safety records as water depths up to 2,000 m are considered for oilfield developments offshore Brazil in the future.

  13. Bathymetry Offshore Sumatra First Comprehensive map of International Data Sets

    NASA Astrophysics Data System (ADS)

    Gaedicke, C.; Ladage, S.; Soh, W.; Weinrebe, W.; Tappin, D. R.; Henstock, T.; McNeill, L.; Sibuet, J.; Klingelhoefer, F.; Singh, S.; Flueh, E.; Djajadihardja, Y.

    2006-12-01

    Knowledge of the bathymetry offshore Sumatra is of great importance for geohazard risk assessment, modelling of tsunami runup heights and development of tsunami early warning systems as well as for the general understanding of plate boundary processes and morphotectonic features. Since the devastating December 26, 2004 Sumatra-Andaman Islands earthquake and tsunami a number of marine expeditions, funded by Canada, France, Germany, India, Indonesia, Japan, United Kingdom and the United States have acquired bathymetric data over the southern part of the earthquake rupture zone but also along strike the whole Sunda trench. Here we present the first compilation of these bathymetric data sets as one bathymetric map. The bathymetric data acquired up to date covers a vast part of the trench, continental slope and in part also of the fore arc basins. The map incorporates the newest data sets from 2005 of the British high-resolution HMS SCOTT survey, the French Marion-Dufresene "Aftershocks" and the Japanese Natsushima cruises. While these surveys concentrated on the southern rupture zone of the Dec. 26th, 2004 earthquake, the German RV SONNE SeaCause and Sumatra cruises in 2005 and 2006 mapped the March 28th 2005 rupture area as well as large parts of the central Sunda trench and slope and in part the fore arc basins. Surveys reaching back to 1997 covering parts of the Sunda Strait and offshore southern Sumatra are also incorporated. A nearly complete coverage of the Sunda trench and slope area in the north is achieved. In the south data gaps on the slope still exist. This map compilation is a collaborative international effort initiated and partly funded by InterMARGINS. It is a major contribution to the Indonesian and international science community.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  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 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.

  1. 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

  2. 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.

  3. Application of seismic sequence concepts to basin evolution and petroleum exploration, Pletmos basin, offshore South Africa

    SciTech Connect

    Keenan, J.H.G. )

    1989-03-01

    As a result of excellent seismic data, shallow burial depths, and slow subsidence rates, 67 type 1 and type 2 unconformities were identified in the postrift Cretaceous section of the Pletmos subbasins. The purpose of this study was to develop a seismic sequence-stratigraphic framework for the mid-Valanginian to mid-Campanian sequences as a basis for future petroleum exploration. The study further developed the recent stratigraphic techniques proposed by Exxon. Sixteen of the 67 type 1 and type 2 unconformities could be correlated directly with Exxon's global third-order cycles; the remaining 51, interpreted to be fourth- and fifth-order cycles, could be grouped into megasequences comprising 2 to 6 sequences, bounded by major third-order type 1 unconformities. The study demonstrates the complex interplay of variations in sea level fluctuation, differential subsidence rates, sediment supply, and tectonic stability and the resultant wide range of geometries and styles in depositional environments. By using seismic sequence concepts, these variables can be accounted for and can be made with greater assurance. Further analyses of lowstand systems tracts are underway to localize stratigraphic trap prospects to be drilled in the near future.

  4. 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.

  5. EMS offshore. A new horizon for paramedics.

    PubMed

    Mallard, A S

    1991-10-01

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

  6. 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.

  7. EMS offshore. A new horizon for paramedics.

    PubMed

    Mallard, A S

    1991-10-01

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

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. Arctic and offshore research: Technology status report

    SciTech Connect

    Not Available

    1987-01-01

    DOE's Morgantown Energy Technology Center and the DOE Fossil Energy Office of Technical Coordination in coordination with the Office of Oil, Gas, and Shale Technology are performing the following activities in Arctic and Offshore Research (AOR): AOR Energy-Related Technology Data Base Development: AOR Seminars and Workshops; Arctic and Offshore Energy Research Coordination; and Arctic and Offshore Research. This research includes: analysis of ice island generation, and prediction of drift paths; field and laboratory determination of the engineering properties of multiyear ice, and the interaction of sea ice with offshore structures; investigation of the effects of ice accretion on offshore structures; measurements of seismic acceleration and velocity for analyzing vibration in and stability of offshore structures; analysis of ice gouging in deep water (150 to 210 feet) in the Artic Ocean, and numerical simulation modeling of the gouging process; analysis of the location and origin of the ice-ridging shear zone; analysis of sea-ice thickness using airborne-radar sensing techniques; and improvement of permafrost detection techniques, analysis of permafrost characteristics, and how temperature and salinity influence seabed freezing. DOE AOR was initiated in the fall of 1982. Current activities include developing the Arctic energy-related technology data base and initiating most of the research described above (except multiyear ice properties, pipeline research, and subice systems development). 12 refs., 11 figs., 4 tabs.

  15. Arctic and offshore research. Technology status report

    SciTech Connect

    Not Available

    1985-10-01

    DOE's Morgantown Energy Technology Center (METC) and the DOE Fossil Energy Office of Oil, Gas, and Shale Technology are performing the following activities in Arctic and Offshore Research (AOR): (1) AOR Energy-Related Technology Data Base Development; (2) AOR seminars and workshops; (3) Arctic and Offshore Energy Research Coordination; (4) Arctic and Offshore Research which includes analysis of ice island generation, and prediction of drift paths; field and laboratory determination of (1) the engineering properties of multiyear ice, and (2) the interaction of multiyear ice with offshore structures; analysis of ice gouging in deep water (150 to 210 feet) in the Arctic Ocean, and numerical simulation modeling of the gouging process; analysis of the location and origin of the ice-ridging shear zone; analysis of sea-ice thickness using airborne radar sensing techniques; improvement of permafrost detection techniques, and analysis of permafrost characteristics; investigation of the effects of ice accretion and corrosion on offshore structures; measurements of seismic acceleration and velocity for analyzing vibration in and stability of off-shore structures; detection of oil spills that occur below the Arctic ice pack; analysis of the effects of frost heave and corrosion on pipelines; (5) Advanced Recovery Technologies; and (6) Subice Systems Development. Current activities include determining the Arctic bibliographic data base and initiating most of the research described above (except multiyear ice properties, pipeline research, and subice systems development). 10 refs., 15 figs., 3 tabs.

  16. 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.

  17. 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.

  18. Problems unique to offshore measurement

    SciTech Connect

    Young, J.G.

    1995-12-01

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

  19. Arctic & Offshore Technical Data System

    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

  20. 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.

  1. Seafloor bathymetry and gravity from the ALBACORE marine seismic experiment offshore southern California

    NASA Astrophysics Data System (ADS)

    Shintaku, N.; Weeraratne, D. S.; Kohler, M. D.

    2010-12-01

    Although the North America side of the plate boundary surrounding the southern California San Andreas fault region is well studied and instrumented, the Pacific side of this active tectonic boundary is poorly understood. In order to better understand this complex plate boundary offshore, its microplate structures, deformation, and the California Borderland formation, we have recently conducted the first stage of a marine seismic experiment (ALBACORE - Asthenospheric and Lithospheric Broadband Architecture from the California Offshore Region Experiment) deploying 34 ocean bottom seismometers offshore southern California in August 2010. We present preliminary data consisting of seafloor bathymetry and free air gravity collected from this experiment. We present high-resolution maps of bathymetry and gravity from the ALBACORE experiment compiled with previous ship track data obtained from the NGDC (National Geophysical Data Center) and the USGS. We use gravity data from Smith and Sandwell and study correlations with ship track bathymetry data for the features described below. We observe new seafloor geomorphological features far offshore and within the Borderland. Steep canyon walls which line the edges of the Murray fracture zone with possible volcanic flows along the canyon floor were mapped by multibeam bathymetry for the first time. Deep crevices juxtaposed with high edifices of intensely deformed plateaus indicate high strain deformation along the arcuate boundary of the Arguello microplate. Small volcanic seamounts are mapped which straddle the Ferrelo fault (Outer Borderland) and San Pedro fault (Inner Borderland), and appear to exhibit fracture and fault displacement of a portion of the volcanic centers in a left-lateral sense. A large landslide is also imaged extending approximately 6 miles in length and 3 miles in width in the Santa Cruz basin directly south of Santa Rosa Island. Deformation associated with capture of Arguello and Patton microplates by the

  2. Submarine landslides hazard offshore Israel

    NASA Astrophysics Data System (ADS)

    Katz, Oded

    2016-04-01

    Submarine landslides pose significant natural hazards. They can damage seafloor infrastructure, such as that used to recover oil and gas or seafloor telecommunication cables, and even generate tsunamis. We recently mapped 447 submarine landslides across the east Mediterranean continental slope, offshore Israel (hereafter the studied area). The mapped landslides are found at water depths of 130 m to 1,000 m and their volume ranges 10-5 - 100 km3. Landslide scars are typically related to a critical slope angle of >4° . Landslides at the northern part of the studied area are spatially associated with fault scarps and are smaller than the ones on the southern part. In this work we evaluate the potential hazard to population and to on- and off- shore facilities posed by submarine landslides across the studied area. We integrate three independent probabilities: (1) the probability for a landslide event of a given volume, based on the size distribution of the mapped landslides; (2) the probability for a landslide event in a given time, based on the reoccurrence time of triggering earthquakes with M >7, and on a 50,000 years general time frame derived from submarine landslides identified across the Mediterranean Sea; (3) the probability for a landslide event in a given area, based on the distribution of slopes exceeding the critical angle. Overall, the fraction of potentially destructive landslides (size > 0.1 km3) is small, 0.05. Thus, considering typical planning time scales of less than 100 years, the calculated hazard is only moderate. The small fraction of landslides with tsunamogenic potential (size > 1 km3), suggests that the hazard for landslide-induced tsunamis along the open slope part of the studied area is small. Landslides in the southern part of the studied area are larger and thus present a somewhat bigger potential source of tsunami waves.

  3. Optimization program for offshore network

    SciTech Connect

    Oster, J.P.

    1983-08-01

    The Upper Zakum field, 50 km (31 miles) long and 30 km (19 miles) wide, is located offshore the United Arab Emirates, in latitude 25/sup 0/ North and in longitude 53/sup 0/30' East, approximately. The field facilities include one central production platform (central complex), three satellite platforms for primary separation, about 60 drilling or injection platforms, and one exporting terminal located on Zirku Island. Drilling and injection platforms are connected to the satellite platforms through 134 flowlines ranging from 4 to 12 in. in diameter. Connection between each satellite platform and the central complex is ensured through three special-purpose trunklines designed to convey crude oil and gas from satellites to a central complex, and injection water from the central complex to satellites. The trunklines are either 18 or 24 in. in diameter. Crude oil is dispatched from the central complex to Zirku Island through a 42-in. main oil line. This paper describes a program designed to optimize the pipelaying procedures. Since May 1980, the program has been run in the field office on a Hewlett Packard 9845 T computer. Once the yearly overall pipelaying schedule was determined, the program was run weekly to optimize the next 10 lines representing about 2 months of lay barge work. Such optimum monitoring and record keeping of the entire construction effort from the pipe mill to the riser installation would not have been possible without this management tool which certainly saved considerable barge transfer and stand-by times, resulting in an important reduction of the overall investment.

  4. 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.

  5. 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.

  6. 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.

  7. Basement geology in the sedimentary basins of Nigeria

    NASA Astrophysics Data System (ADS)

    Avbovbo, Akpo A.

    1980-07-01

    In Nigeria, the dominant type of basement rock intersected by wells drilled for hydrocarbons, limestone, or water is granite. The three sedimentary basins in Nigeria are underlain by continental crust except in the Niger delta, where the basement rock is interpreted to be oceanic crust. Most of the wells that penetrated the basement are in the Eastern Dahomey embayment of western Nigeria. A maximum thickness of about 12,000 m of sedimentary rocks is attained in the offshore western Niger delta, but maximum thicknesses of sedimentary rocks are about 2,000 m in the Chad basin and only 500 m in the Sokoto embayment.

  8. 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.

  9. Federal offshore statistics: leasing - exploration - production - revenue

    SciTech Connect

    Essertier, E.P.

    1984-01-01

    Federal Offshore Statistics is a numerical record of what has happened since Congress gave authority to the Secretary of the Interior in 1953 to lease the Federal portion of the Continental Shelf for oil and gas. The publication updates and augments the first Federal Offshore Statistics, published in December 1983. It also extends a statistical series published annually from 1969 until 1981 by the US Geological Survey (USGS) under the title Outer Continental Shelf Statistics. The USGS collected royalties and supervised operation and production of minerals on the Outer Continental Shelf (OCS) until the Minerals Management Service (MMS) took over these functions in 1982. Statistics are presented under the following topics: (1) highlights, (2) leasing, (3) exploration and development, (4) production and revenue, (5) federal offshore production by ranking operator, 1983, (6) reserves and undiscovered recoverable resources, and (7) oil pollution in the world's oceans.

  10. Slimhole advancements allow economic offshore exploitation

    SciTech Connect

    Shanks, E.

    1995-07-01

    Slimhole drilling technology is a proven method to reduce well cost in remote areas of the world. It also provides advantages in offshore drilling and production applications where smaller tubular sizes can make marginal fields economic. The technological accomplishments within the industry have provided a sound basis to apply slimhole technology offshore worldwide. And it is feasible to develop methods to apply this technology to more sever applications, including deeper wells, high-pressure wells and hole problem areas, such as troublesome shales. Such applications will require additional technology development to be adequately prepared for proper well designs and possible contingencies during drilling. From the experience to date with this technology, it is feasible to design wells to total drilled depths of 12,000 ft--15,000 ft onshore or offshore. For purposes of this article, a slimhole well is one with the diameter at TD less than 6-in.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Near-Vertical Moho Reflections Under the Hanoi Basin, Vietnam

    NASA Astrophysics Data System (ADS)

    Dinh, T. V.; Harder, S. H.

    2008-12-01

    Surface expression of the Red River fault, a major strike-slip fault originating from the India-Eurasian collision, terminates as a large pull-apart basin in northern Vietnam. The onshore part is called the Hanoi basin and is an extension of the larger offshore Song Hong basin. Rifting in these basins began early Eocene with inversion in the late Miocene and continued subsidence today. Gravity studies indicate crustal thinning under the Hanoi basin, however both the Hanoi and Song Hong basins are in near isostatic balance resulting in relatively small gravity anomalies from large crustal-scale features. Hence, seismic methods would seem to be a more appropriate method for studying crustal structure in this situation. In January 2008 we shot the first deep crustal seismic lines in Southeast Asia in and near the Hanoi basin. Crustal seismic experiments in densely populated areas are challenging because of the high cultural noise levels and the lack of available space for shotpoints. This experiment however produced an unusually strong near-vertical reflection from the Moho under the Hanoi basin as well as a number of other arrivals. Analyses of these arrivals indicate the crust is 27 km thick, thinner than estimated from gravity data. They also show the Moho is a complex reflector with a high impedance contrast.

  16. 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

  17. Fouling of offshore structures in China--a review.

    PubMed

    Yan, Tao; Yan, Wen Xia

    2003-04-01

    Biofouling on ships' hulls and other man-made structures is a major economic and technical problem around the world. In recent decades, the development and growth of the offshore oil and gas industry has led to increased interest in, and studies on marine fouling in offshore regions. This paper reviews the effects of marine fouling on offshore structures, the development of offshore fouling studies in China, and the characteristics of marine fouling in relevant areas. Future research strategies are also proposed.

  18. 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

  19. 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.

  20. 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.

  1. 47 CFR 22.1037 - Application requirements for offshore stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Application requirements for offshore stations. 22.1037 Section 22.1037 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Offshore Radiotelephone Service § 22.1037 Application requirements for offshore stations. Applications for...

  2. 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... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Hazardous Locations § 111.105-33 Mobile offshore drilling units. (a) Applicability. This section applies to each mobile offshore drilling unit. (b) Definitions. As used in...

  3. 78 FR 63233 - National Offshore Safety Advisory Committee; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... Equipment in Hazardous Areas on Foreign Flag Mobile Offshore Drilling Units. (4) Safety Impact of Liftboat... Equipment in Hazardous Areas on Foreign Flag Mobile Offshore Drilling Units (MODUs); (d) Safety Impact of... SECURITY Coast Guard National Offshore Safety Advisory Committee; Meeting AGENCY: Coast Guard, DHS....

  4. 78 FR 18614 - National Offshore Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-27

    ... Continental Shelf (OCS); (b) Electrical Equipment in Hazardous Areas on Foreign Flag Mobile Offshore Drilling... SECURITY Coast Guard National Offshore Safety Advisory Committee AGENCY: United States Coast Guard. ACTION: Committee Management; Notice of Federal Advisory Committee Meetings. SUMMARY: The National Offshore...

  5. 46 CFR 15.520 - Mobile offshore drilling units.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Mobile offshore drilling units. 15.520 Section 15.520... REQUIREMENTS Manning Requirements; Inspected Vessels § 15.520 Mobile offshore drilling units. (a) The requirements in this section for mobile offshore drilling units (MODUs) supplement other requirements in...

  6. 46 CFR 15.520 - Mobile offshore drilling units.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Mobile offshore drilling units. 15.520 Section 15.520... REQUIREMENTS Manning Requirements; Inspected Vessels § 15.520 Mobile offshore drilling units. (a) The requirements in this section for mobile offshore drilling units (MODUs) supplement other requirements in...

  7. 46 CFR 15.520 - Mobile offshore drilling units.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Mobile offshore drilling units. 15.520 Section 15.520... REQUIREMENTS Manning Requirements; Inspected Vessels § 15.520 Mobile offshore drilling units. (a) The requirements in this section for mobile offshore drilling units (MODUs) supplement other requirements in...

  8. 77 FR 17491 - National Offshore Safety Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-26

    ... SECURITY Coast Guard National Offshore Safety Advisory Committee AGENCY: United States Coast Guard.... SUMMARY: The National Offshore Safety Advisory Committee (NOSAC) will meet on April 11 and 12, 2012, in... affecting the oil and gas offshore industry. These meetings are open to the public. DATES: NOSAC will...

  9. 46 CFR 111.105-33 - Mobile offshore drilling units.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Mobile offshore drilling units. 111.105-33 Section 111... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Hazardous Locations § 111.105-33 Mobile offshore drilling units. (a) Applicability. This section applies to each mobile offshore drilling unit. (b) Definitions. As used in...

  10. 46 CFR 111.105-33 - Mobile offshore drilling units.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Mobile offshore drilling units. 111.105-33 Section 111... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Hazardous Locations § 111.105-33 Mobile offshore drilling units. (a) Applicability. This section applies to each mobile offshore drilling unit. (b) Definitions. As used in...

  11. 46 CFR 15.520 - Mobile offshore drilling units.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Mobile offshore drilling units. 15.520 Section 15.520... REQUIREMENTS Manning Requirements; Inspected Vessels § 15.520 Mobile offshore drilling units. (a) The requirements in this section for mobile offshore drilling units (MODUs) supplement other requirements in...

  12. 46 CFR 15.520 - Mobile offshore drilling units (MODUs).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Mobile offshore drilling units (MODUs). 15.520 Section... MANNING REQUIREMENTS Manning Requirements; Inspected Vessels § 15.520 Mobile offshore drilling units... endorsement on an MMC as offshore installation manager (OIM), barge supervisor (BS), or ballast...

  13. 46 CFR 111.105-33 - Mobile offshore drilling units.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Mobile offshore drilling units. 111.105-33 Section 111... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Hazardous Locations § 111.105-33 Mobile offshore drilling units. (a) Applicability. This section applies to each mobile offshore drilling unit. (b) Definitions. As used in...

  14. 46 CFR 111.105-33 - Mobile offshore drilling units.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Mobile offshore drilling units. 111.105-33 Section 111... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Hazardous Locations § 111.105-33 Mobile offshore drilling units. (a) Applicability. This section applies to each mobile offshore drilling unit. (b) Definitions. As used in...

  15. 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…

  16. 46 CFR 126.170 - Carriage of offshore workers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... workers authorized for carriage exceed 36, unless the vessel meets the applicability and construction... 46 Shipping 4 2014-10-01 2014-10-01 false Carriage of offshore workers. 126.170 Section 126.170... CERTIFICATION General § 126.170 Carriage of offshore workers. (a) Offshore workers may be carried aboard an...

  17. 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…

  18. 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.

  19. 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

  20. Offshore-onshore recent tectonic deformations in the eastern Rif and its foreland (Alhoceima-Nador, Morocco)

    NASA Astrophysics Data System (ADS)

    Ruano, Patricia; Galindo-Zaldívar, Jesús; Comas, Menchu; Chalouan, Ahmed; Azzouz, Omar; Jesús Román-Alpiste, Manuel; Pedrera, Antonio; Sanz de Galdeano, Carlos; López-Garrido, Ángel Carlos; Benmakhlouf, Mohamed; Roldán-García, Francisco Javier; Anahnah, Farida; González-Castillo, Lourdes

    2014-05-01

    The Rif Cordillera is formed by the southwestwards emplacement of the internal zones on the African foreland in the western Alboran Sea. However, the recent deformations are driven also by interaction with the NW-SE convergence of the Eurasian and African plates. The eastern Rif and its foreland constitute a key region to study the variability in structure and stresses related to a lateral boundary of this Alpine Cordillera. The continental crust of the Rif thinned toward Alboran Sea. The onshore and offshore area nearby the coast line, between Al Hoceima and Nador are suitable for recent tectonics studies due to the presence of wide Neogene and Quaternary basins that contribute to record the activity of recent structures. Multichannel seismic reflection data obtained along the coast during the GASALB cruise in November 2011, together with available data, allows to characterize the differences of the Rif and forleland Neogene-Quaternary basins. Offshore results are compared with field observations, that detailed cover several areas. In the Rif Cordillera (Al Hoceima area), recent basins open towards the Alboran Sea are formed by the active roughly N-S oriented faults in this seismogenic area. They are mainly normal in onshore area and becomes strike-slip offshore connecting with sinistral Al-Idrisi fault zone. In contrast, in the foreland represented by the Trois Fourches area, onshore N-S faults are inactive and are developed above a very well exposed folded detachment. Paleostress data in this area support the activity of the exhumed low-angle faults with NE-SW extension and a late radial extension. These new data allows underline the different stresses and age of deformation in the Rif and its foreland and support a westward displacement of deformation along recent time. Then, the most active and hence higher seismic hazard along Moroccan coast, also related to possible tsunamogenic faults, are located offshore Alhoceima area.

  1. 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

  2. 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.

    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

  3. 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.

  4. 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.

  5. 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.

  6. 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…

  7. 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...

  8. Accord near for offshore California oil shipments

    SciTech Connect

    Not Available

    1993-02-15

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

  9. 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 §...

  10. 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.

  11. 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)…

  12. 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.

  13. 31 CFR 548.406 - 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. 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 Interpretations §...

  14. 31 CFR 548.406 - 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. 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 Interpretations §...

  15. 31 CFR 548.406 - 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. 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 Interpretations §...

  16. 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...

  17. 31 CFR 548.406 - 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. 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 Interpretations §...

  18. Analysis techniques for offshore platform tieback systems

    SciTech Connect

    Griffith, D.L.

    1983-03-01

    The development of offshore fields using subsea drilling templates and tie-back equipment has become an accepted method of achieving early production. This technical paper gives an introduction to tie-back systems, presents a method of analyzing them, discusses the loading conditions that affect tie-back systems, and describes a method of accounting for loading conditions during analysis.

  19. 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.

  20. 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.

  1. 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.

  2. 31 CFR 594.407 - 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. 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 REGULATIONS...

  3. 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...

  4. 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.

  5. 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...

  6. 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...

  7. 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...

  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. Wrench faulting in the Canada Basin, Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Hutchinson, D. R.; Jackson, H. R.; Shimeld, J.; Houseknecht, D. W.; Chian, D.; Li, Q.; Saltus, R. W.; Oakey, G. N.

    2015-12-01

    Synthesis of seismic velocity, potential field, and geologic data from within the Canada Basin of the Arctic Ocean and its surrounding margins suggests that a northeast-trending structural fabric has influenced the origin, evolution, and current tectonics of the basin. This fabric is defined by a diverse set of observations, including (1) a magnetic lineament extending from offshore Prince Patrick Island to the bend in the Canada Basin Gravity Low that separates higher magnetic amplitudes to the northwest from a region of more subdued anomalies to the southeast; (2) the orientation of the 600-km long Northwind Escarpment along the edge of the Canada Basin; (3) a large, linear, positive magnetic anomaly that parallels Northwind Escarpment; (4) negative flower structures along the base of the Northwind Escarpment identified in seismic reflection profiles; (5) the edges of a linear, 150-km-long by 20-km-wide by 2000-m deep, basin in the Chukchi Plateau; (6) the sub-parallel ridges of Sever Spur along the Canadian margin north of Prince Patrick Island; (7) an oblong gravity low interpreted to indicate thick sediments beneath an inferred rift basin at 78oN in ~3600 m water depth; (8) the offshore extensions of the Canning sinistral and Richardson dextral fault zones; (9) the offshore extension of the D3 magnetic terrain of Saltus et al. (2011); and (10) the association of dredged rocks of the Chukchi Borderland with the Pearya terrane ~2000 km northeast of its present location (Brumley et al., 2015). Ongoing deformation of the Beaufort margin by impingement of the Brooks Range tectonic front is recorded by modern seismicity along the Canning and Richardson fault zones, which imply that deformation is accommodated by slip along the northeast-trending fabric. Together, these features are interpreted to indicate long-lived northeast-southwest oriented tectonic fabric in the development of the Canada Basin from initial rifting to modern deformation of the Beaufort margin

  10. 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

  11. 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

  12. 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

  13. Integrated reservoir study - M/T structure offshore Abu Dhabi

    SciTech Connect

    Cartier, G.; Combes, J.T. des; Hassan, T.H.

    1995-08-01

    A multidisciplinary approach involving geology, geophysics, petrophysics and reservoir engineering is used to assess the oil-bearing Thamama reservoirs in the Offshore Abu Dhabi M/T Structure. The structural definition is hampered by subtle variations of the seismic velocities created by shallow high velocity channel fills. Improved time to depth conversion was achieved through detailed velocity studies and layer caking. As currently defined at the Thamama level, the M/T structure is a gentle low relief feature with closure of about 125 feet. The Lower Cretaceous Thamama Group comprises the producing zones and consists of a succession which was deposited over an extensive carbonate ramp platform. Seven depositional environments and fifteen associated lithofacies range from slope or basin edge, gradually passing to fore shoal, algal shoal, and rudistid backshoal of the inner ramp. Three third order sequences, their associated systems tracts, sequence boundaries and shallowing upwards parasequences are recognised. Based on geological and petrophysical data, a rock type scheme was developed as a basis for detailed reservoir layering and simulation studies. The main diagenetic processes which adversely affect porosity are circumgranular, ferroan and non-ferroan calcite and saddle dolomite cementation, while leaching is the primary porosity-enhancing process. Conventional and special core analyses indicate that specific poroperm, petrophysical and engineering parameters can be assigned to various rock types. The integration of all disciplines will optimise future appraisal drilling and lead to a more efficient development strategy of this field.

  14. 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.; Johnson, Samuel Y.; Cochran, Susan A.

    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

  15. 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

  16. 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.

  17. 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.

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

    DOE PAGES

    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

  19. Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California

    USGS Publications Warehouse

    Ryan, H.F.; Parsons, T.; Sliter, R.W.

    2008-01-01

    A new fault map of the shelf offshore of San Francisco, California shows that faulting occurs as a distributed shear zone that involves many fault strands with the principal displacement taken up by the San Andreas fault and the eastern strand of the San Gregorio fault zone. Structures associated with the offshore faulting show compressive deformation near where the San Andreas fault goes offshore, but deformation becomes extensional several km to the north off of the Golden Gate. Our new fault map serves as the basis for a 3-D finite element model that shows that the block between the San Andreas and San Gregorio fault zone is subsiding at a long-term rate of about 0.2-0.3??mm/yr, with the maximum subsidence occurring northwest of the Golden Gate in the area of a mapped transtensional basin. Although the long-term rates of vertical displacement primarily show subsidence, the model of coseismic deformation associated with the 1906 San Francisco earthquake indicates that uplift on the order of 10-15??cm occurred in the block northeast of the San Andreas fault. Since 1906, 5-6??cm of regional subsidence has occurred in that block. One implication of our model is that the transfer of slip from the San Andreas fault to a fault 5??km to the east, the Golden Gate fault, is not required for the area offshore of San Francisco to be in extension. This has implications for both the deposition of thick Pliocene-Pleistocene sediments (the Merced Formation) observed east of the San Andreas fault, and the age of the Peninsula segment of the San Andreas fault.

  20. Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California

    NASA Astrophysics Data System (ADS)

    Ryan, H. F.; Parsons, T.; Sliter, R. W.

    2008-10-01

    A new fault map of the shelf offshore of San Francisco, California shows that faulting occurs as a distributed shear zone that involves many fault strands with the principal displacement taken up by the San Andreas fault and the eastern strand of the San Gregorio fault zone. Structures associated with the offshore faulting show compressive deformation near where the San Andreas fault goes offshore, but deformation becomes extensional several km to the north off of the Golden Gate. Our new fault map serves as the basis for a 3-D finite element model that shows that the block between the San Andreas and San Gregorio fault zone is subsiding at a long-term rate of about 0.2-0.3 mm/yr, with the maximum subsidence occurring northwest of the Golden Gate in the area of a mapped transtensional basin. Although the long-term rates of vertical displacement primarily show subsidence, the model of coseismic deformation associated with the 1906 San Francisco earthquake indicates that uplift on the order of 10-15 cm occurred in the block northeast of the San Andreas fault. Since 1906, 5-6 cm of regional subsidence has occurred in that block. One implication of our model is that the transfer of slip from the San Andreas fault to a fault 5 km to the east, the Golden Gate fault, is not required for the area offshore of San Francisco to be in extension. This has implications for both the deposition of thick Pliocene-Pleistocene sediments (the Merced Formation) observed east of the San Andreas fault, and the age of the Peninsula segment of the San Andreas fault.

  1. Sea-bed image off-shore County Antrim, Northern Ireland

    NASA Astrophysics Data System (ADS)

    Bulat, Joseph; Gafeira, Joana D. L.; Quinn, Martyn F.; Reay, Derek M.

    2010-05-01

    In September 2009 the British Geological Survey acting for the Department of Enterprise, Trade and Industry (DETI) of Northern Ireland commissioned a high-resolution multichannel nearshore 2D seismic survey in the North Channel, offshore Northern Ireland. The purpose of the survey was to image the Permian and Triassic Halite successions known to exist offshore for the purpose of mapping and evaluating their potential as off-shore gas storage sites. In addition to the high-resolution seismic data, swath bathymetry was also acquired. These swath data have been gridded into a 10m by 10m data array that although not entirely continuous, does provide a detailed image of the sea floor. The image suggests a complex interplay between the underlying geology and the strong tidal currents that are prevalent within the North Channel. Volcanic features and basin faults have a clear expression on the sea-bed. In slightly deeper water obvious sediment wave-fields are observed as well as very pronounced linear mounds with an ENE- WSW trend. These somewhat enigmatic features do not appear to have any obvious direct relationship with underlying geology in the area. Similar features have been observed regionally in the Beaufort's Dyke, offshore northern Ulster and appear to be very similar to features in the Irish Sea described by other authors as Trochoidal sediment waves. In shallower waters, linear sinuous banks are imaged. The availability of both swath and coincident 2D high-resolution seismic profiles provides an interesting opportunity to investigate the relationship between sea-bed morphology and deeper geological structures.

  2. 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.

  3. Potential earthquake faults offshore Southern California, from the eastern Santa Barbara Channel south to Dana Point

    USGS Publications Warehouse

    Fisher, M.A.; Sorlien, C.C.; Sliter, R.W.

    2009-01-01

    Urban areas in Southern California are at risk from major earthquakes, not only quakes generated by long-recognized onshore faults but also ones that occur along poorly understood offshore faults. We summarize recent research findings concerning these lesser known faults. Research by the U.S. Geological Survey during the past five years indicates that these faults from the eastern Santa Barbara Channel south to Dana Point pose a potential earthquake threat. Historical seismicity in this area indicates that, in general, offshore faults can unleash earthquakes having at least moderate (M 5-6) magnitude. Estimating the earthquake hazard in Southern California is complicated by strain partitioning and by inheritance of structures from early tectonic episodes. The three main episodes are Mesozoic through early Miocene subduction, early Miocene crustal extension coeval with rotation of the Western Transverse Ranges, and Pliocene and younger transpression related to plate-boundary motion along the San Andreas Fault. Additional complication in the analysis of earthquake hazards derives from the partitioning of tectonic strain into strike-slip and thrust components along separate but kinematically related faults. The eastern Santa Barbara Basin is deformed by large active reverse and thrust faults, and this area appears to be underlain regionally by the north-dipping Channel Islands thrust fault. These faults could produce moderate to strong earthquakes and destructive tsunamis. On the Malibu coast, earthquakes along offshore faults could have left-lateral-oblique focal mechanisms, and the Santa Monica Mountains thrust fault, which underlies the oblique faults, could give rise to large (M ??7) earthquakes. Offshore faults near Santa Monica Bay and the San Pedro shelf are likely to produce both strike-slip and thrust earthquakes along northwest-striking faults. In all areas, transverse structures, such as lateral ramps and tear faults, which crosscut the main faults, could

  4. 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

  5. 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.

  6. The Onset of the Messinian Salinity Crisis along the offshore Betic Range

    NASA Astrophysics Data System (ADS)

    Ochoa, Diana; Sierro, Francisco J.; Lofi, Johanna; Maillard, Agnes; Driussi, Olivier; Flores, Jose-Abel

    2014-05-01

    During the latest Miocene tectonic-driven processes triggered the closure of the gateways connecting the Atlantic and the Mediterranean seas. Consequently, the Mediterranean Sea experienced major changes on sea level, water chemistry, faunal assemblages, and sedimentary patterns. The extended presence of thick evaporitic sequences on both marginal and deep areas indicates the magnitude of this event and its basin-wide nature. However most of the evidence explaining the origin, nature and system responses to this crisis, also known as the Messinian Salinity Crisis (MSC), comes from continental/shallow marine areas. Hence, responses of deep marine environments to the MSC and their correlation with marginal regions are still poorly understood. In this work, we aim to provide a chronostratigraphic framework for sediments located along the offshore Betic Range (Valencia basin and Alicante shelf). This area, which is the offshore extension of the Betic gateway, potentially can help to correlate onland sedimentary successions with seismic stratigraphic sequences recognized at intermediate-depths. Thus, moving a step further on the marginal-deep basin correlation across Western Mediterranean. An age model was built by using several planktonic foraminifera events that have been astronomically dated in other Mediterranean sections. In addition, sonic and resistivity well logs were tuned to the astronomical target curves. Well log patterns allow us to identify a cyclical sequence of gypsum on the Alicante shelf, which is very similar to the one present onshore in the Sorbas basin. Our preliminary results suggest that the first gypsum bed is conformable overlying Messinian marls. These results support the idea of a synchronous precipitation of the Lower Primary Gypsum across the entire Mediterranean basin. Finally, well-logging and micropaleontological data is being integrated with recently gathered 2D-seismic data (SIMBAD cruise), intentionally tied to some of our studied

  7. 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.; Johnson, Samuel Y.; Cochran, Susan A.

    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

  8. Analysis of offshore atmospheric diffusion characteristics

    SciTech Connect

    Hiraga, Kunio; Omoto, Akira; Takahashi, Keiichi; Momoi, Kazuyoshi

    1994-12-31

    Although almost all of the thermal and nuclear power stations in Japan are located on the coastline to take advantage of seawater available to condense steam, offshore siting is one of the candidates for the future plant sitting. Figures developed by Pasquill-Gifford model has been conventionally utilized in analyzing atmospheric diffusion of gaseous effluent from power plants. However, there are limitations to apply this to offshore plants because these figures are based on inland diffusion experiments and this model does not specifically take into consideration the effects of thermal capacity of seawater, its surface roughness and so on. Even in the case of coastline sitting, atmospheric diffusion of gaseous effluent might be affected by atmospheric diffusion characteristics above seawater. With this background gaseous, diffusion experiments were conducted at one of TEPCo`s (Tokyo Electric Power Company) coastline power station and empirical formula to model atmospheric diffusion above seawater has been developed.

  9. Industry approach to aging offshore platforms

    SciTech Connect

    Wisch, D.J. )

    1993-05-01

    The US offshore oil industry started in the late 1940's in the Gulf of Mexico. At the beginning of 1992, there were over 4,000 platforms in US coastal waters with the oldest being 44 years old. Since platforms in the Gulf of Mexico are demanned and shut-in prior to the passage of a hurricane, the life and environmental safety records have been excellent with these mitagation procedures inplace. However, as the facilities continue to age and new technology is developed that allows for additional oil recovery, the desire to extend service life is becoming more frequent. In efforts to manage both the safety and economic aspects of the facilities, many operators have established inhouse programs for inspection and evaluation of their platform inventories. The industry is currently involved in collaborating in efforts to develop general guidelines for all facilities for establishing Recommended Practice for the continued safe and economical use of offshore platforms. 11 refs., 3 figs.

  10. Drilling tools for continuous offshore operations

    SciTech Connect

    Gelfgat, M.Y.; Surkov, D.V.; Buyanovsky, I.N.

    1995-12-31

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

  11. 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.

  12. 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.

  13. 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

  14. 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.; Johnson, Samuel Y.; Cochran, Susan A.

    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

  15. 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.

  16. 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.

  17. 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.

  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. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 26th Annual offshore technology conference: 1994 Proceedings

    SciTech Connect

    Not Available

    1994-01-01

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

  4. 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.

  5. 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.

  6. 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.

  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. 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.

  9. 77 FR 62247 - Dynamic Positioning Operations Guidance for Vessels Other Than Mobile Offshore Drilling Units...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-12

    ... recommended interim voluntary guidance titled ``Mobile Offshore Drilling Unit Dynamic Positioning Guidance''. The notice recommended owners and operators of Mobile Offshore Drilling Units (MODUs) follow Marine....'' The recommended interim voluntary guidance titled ``Mobile Offshore Drilling Unit (MODU)...

  10. 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

  11. 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.; Johnson, Samuel Y.; Cochran, Susan A.

    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

  12. Reserves in Western Basins

    SciTech Connect

    Caldwell, R.H.; Cotton, B.W.

    1993-12-31

    The objective of this project is to investigate the reserves potential of overpressured tight (OPT) gas reservoirs in three Rocky Mountain basins. These are the Greater Green River Basin (GGRB), Uinta Basin and Piceance Basin. By documenting productive characteristics in these basins and characterizing the nature of the vast gas resources in place, the reserves potential may be understood and quantified. Through this understanding, it is hoped that the oil and gas industry will be encouraged to pursue exploitation of this resource. At this point in time, the GGRB work has been completed and the final report submitted for publication. Work on the Uinta basin has just commenced and work on the Piceance basin will commence next year. Since the GGRB portion of this project has been completed, further discussion centers upon this Basin.

  13. 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.

  14. 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.

  15. Petroleum geology of Campos Basin, Brazil: A successful case history of deep water exploration

    SciTech Connect

    Franke, M.R.; Lugon, H.A.F.; Beraldo, W.L. )

    1990-05-01

    Campos Basin, the most prolific Brazilian basin, produces almost 400,000 bbl of oil per day and contains 70% of the national reserves. The basin is located on the southeastern coast of Brazil, covering a prospectable area of 100,000 km{sup 2} Campos is a passive continental margin basin originated by the breakup of Pangea and the rifting of the South American and African plates in the Early Cretaceous. The basin's sedimentary section encompasses three megasequences: nonmarine, transitional, and marine, ranging in age from Neocomian to Holocene. Hydrocarbon generation is related to nonmarine organic-rich shales and marls, and hydrocarbon entrapment assumes ascendent migration along fault planes and through salt gaps toward reservoirs ranging in age from Neocomian to Tertiary (mainly turbiditic sandstones). The first onshore stratigraphic well was drilled based on gravity surveys in 1958. The acquisition of new geophysical data, mainly seismic reflection data, followed after 1968. The first offshore well was drilled in 1971, and in 1974, the first oil field, Garopua, was discovered. Giant hydrocarbon accumulations have been discovered in water depths ranging from 400 to 1,800 m since 1984. As of mid-1989, 35 offshore oil fields have been discovered, 760 million bbl of oil, and 490 bcf of gas have been produced. The basin oil and equivalent gas reserves are estimated in 6.0 billion bbl, 60% of which is located in the deep-water giant oil fields.

  16. 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.

  17. 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.; Johnson, Samuel Y.; 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Protection of offshore structures against corrosion

    SciTech Connect

    Bird, M.F.; Smith, H.M.; Bowley, C.V. Ltd., Denso House, Chapel Road, London SE27 OTR )

    1989-09-01

    Maintaining protection of metal structures against corrosion in marine environments presents problems of surface preparation, accessibility and the limitations of various coating systems. Cathodic protection may be utilized underwater but its effectiveness is severely limited in the splash zone. Hence, reliable coatings are required. Petrolatum tapes have special virtues under these conditions. Following years of experience of the use of petrolatum tapes in difficult environments a comprehensive corrosion protection system was developed for piles, offshore platforms, risers etc. The paper covers both laboratory and field experience leading to commercially viable coatings.

  4. 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.

  5. 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

  6. 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... Minerals Management Service 30 CFR Part 250 RIN 1010-AD47 Annular Casing Pressure Management 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. 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...

  9. 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.......

  10. 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.

  11. 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.

  12. 26th Annual offshore technology conference: 1994 Proceedings

    SciTech Connect

    Not Available

    1994-01-01

    This conference is the world's largest and most comprehensive technical conference and exhibition on offshore resource development. This conference is divided into four volumes with this volume containing conference papers relative to offshore drilling and well completion information. Papers also deal with construction specifications for marine risers and pipelines, along with any relevant installation and performance information.

  13. 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)

  14. 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.

  15. 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.

  16. 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.

    2016-10-01

    SKS arrivals from ocean bottom seismometer (OBS) data from an offshore southern California deployment are analysed for shear wave splitting. The project involved 34 OBSs deployed for 12 months in a region extending up to 500 km 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.

  17. 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.

  18. 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.

  19. Predicting deep reservoir quality, offshore Norway

    SciTech Connect

    Welton, J.E. )

    1996-01-01

    Reducing risk by predicting deep reservoir potential has long been the goal of the explorationist. To successfully evaluate deep reservoir potential requires the integration of information on depositional setting, mineralogy, texture (i.e. grain size and sorting), burial history, temperature, porosity, and permeability. In 1991, prior to the 14th Round, exploration potential on the Halten Terrace (Offshore Norway) was limited by reservoir predictions (based on generalized mineralogy trends) which suggested economic basement was 4000m. However, an integrated reservoir study conducted between 1991-1993 concluded that in certain Jurassic facies, significant deep reservoir potential existed. The study predicted that coarser-grained, quartz-rich braided stream, delta front, and offshore shelf sandbodies would have good porosity and permeability below 4000m, particularly there early chlorite grain coatings were present to inhibit silica cement. In the spring of 1995, the discovery of significant hydrocarbon reserves below 4000m on Block 6406/2 confirmed these predictions and proved that integrated reservoir characterization can lead to accurate deep reservoir quality predictions. The integrated methodology used will be discussed.

  20. 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.

  1. 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

  2. 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.

  3. Offshore winds using remote sensing techniques

    NASA Astrophysics Data System (ADS)

    Peña, Alfredo; Bay Hasager, Charlotte; Gryning, Sven-Erik; Courtney, Michael; Antoniou, Ioannis; Mikkelsen, Torben; Sørensen, Paul

    2007-07-01

    Ground-based remote sensing instruments can observe winds at different levels in the atmosphere where the wind characteristics change with height: the range of heights where modern turbine rotors are operating. A six-month wind assessment campaign has been made with a LiDAR (Light Detection And Ranging) and a SoDAR (Sound Detection and Ranging) on the transformer/platform of the world's largest offshore wind farm located at the West coast of Denmark to evaluate their ability to observe offshore winds. The high homogeneity and low turbulence levels registered allow the comparison of LiDAR and SoDAR with measurements from cups on masts surrounding the wind farm showing good agreement for both the mean wind speed and the longitudinal component of turbulence. An extension of mean wind speed profiles from cup measurements on masts with LiDAR observations results in a good match for the free sectors at different wind speeds. The log-linear profile is fitted to the extended profiles (averaged over all stabilities and roughness lengths) and the deviations are small. Extended profiles of turbulence intensity are also shown for different wind speeds up to 161 m. Friction velocities and roughness lengths calculated from the fitted log-linear profile are compared with the Charnock model which seems to overestimate the sea roughness for the free sectors.

  4. 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

  5. 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.

  6. Surficial geology of the sea floor in Long Island Sound offshore of Plum Island, New York

    USGS Publications Warehouse

    McMullen, K.Y.; Poppe, L.J.; Danforth, W.W.; Blackwood, D.S.; Schaer, J.D.; Ostapenko, A.J.; Glomb, K.A.; 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.

  7. OMAE 1995 -- Proceedings of the 14. international conference on offshore mechanics and arctic engineering. Volume 1, Part B: Offshore technology

    SciTech Connect

    Chakrabarti, S.K.; Gudmestad, O.T.; Sparks, C.; Morrison, D.G.

    1995-12-31

    This conference proceeding represents the second part of the volume of papers related to offshore technology as it relates to design of offshore structures, jacket and floating structures, tension leg platforms, mooring systems, risers, and cables. It also contains papers relating to structural and geotechnical mechanics. Separate abstracts were prepared for 48 papers in this report for inclusion in the information retrieval system.

  8. 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.

  9. 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.

  10. Holocene to Pliocene tectonic evolution of the region offshore of the Los Angeles urban corridor, southern California

    USGS Publications Warehouse

    Bohannon, R.G.; Gardner, J.V.; Sliter, R.W.

    2004-01-01

    comprised a northeast basin slope, and the present offshore basins and Catalina Island formed an emergent or shallowly submerged shelf. Since extensional, compressional, and lateral strains are all locally in evidence, simple notions that this part of southern California underwent a change from Miocene transtension to Quaternary transpression fail to explain our observations.

  11. 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.

  12. Thermal history of the Krishna-Godavari basin, India: Constraints from apatite fission track thermochronology and organic maturity data

    NASA Astrophysics Data System (ADS)

    Sahu, Himansu S.; Raab, Matthias J.; Kohn, Barry P.; Gleadow, Andrew J. W.; Bal, Kiron D.

    2013-09-01

    The Krishna-Godavari (KG) basin, a passive margin Late Carboniferous to Holocene basin along the rifted east coast of India, includes the deltaic and inter-deltaic regions of the Krishna and Godavari rivers onshore and extends into the offshore. It is one of India's premier hydrocarbon-bearing basins. In an attempt to better understand the thermal history of the basin, apatite fission track (AFT) data has been obtained from six exploration wells (five onshore and one offshore). AFT thermal history models as well as other thermal indicators e.g. vitrinite reflectance (VR), Rock-Eval Tmax data reveal that the host rocks are currently at their maximum post-depositional temperatures and that any possible heating related to small-scale tectonism or rifting episodes in the basin bears little significance on the maturation of the sediments. In the case of one borehole (M-1) however, the organic maturity data reveals a period of Oligocene cooling across an unconformity when ∼1000 m of section was eroded due to falling sea-level. This information offers the potential for improved basin modeling of the KG basin.

  13. 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.

  14. Seismic activity of the East Sea, Korea offshore earthquake sequence

    NASA Astrophysics Data System (ADS)

    PARK, E.; Park, S.; Hahm, I.; Kim, Y.

    2013-12-01

    Seismicity in Korea is known to be relatively low compared to China and Japan. But it seems to be more active historically, according to historical documents on earthquake. The magnitudes of historical earthquakes were estimated to be about 4 - 6 by previous studies and there were several events with magnitude over 6. Instrumental earthquakes recorded in 1978 - 2012 seem to be smaller than historical earthquakes, according to the Korea Meteorological Administration (KMA) catalog. Their magnitudes are smaller than 4 in general. Although epicenters of instrumental earthquakes seem to be randomly distributed on the entire Korean Peninsula, some earthquakes occur intensively in several specific areas in the East Sea and the eastern region of Jeju Island. The areas having intensive seismic activity in the East Sea are offshore regions of Uljin (Region A), Yeongdeok (Region B), and Ulsan (Region C) from north to south. Eleven earthquakes of ML 2.0 - 3.2 occurred in Region A on April 2006. The epicenters were distributed within a radius of about 0.7 km. And the focal depths were in the range of 1.6 - 13.0 km (Kang and Shin, 2006). Kang and Shin (2006) propose that the sequence is closely related to the marginal geometry of the Ulleung Basin and the regional stress regime. Seven events with ML 2.1 - 3.0 occurred between September 12 and October 17 in 2007, and four events with ML 2.3 - 3.5 did between 07 December 2008 and 13 January 2009 in Region B. The relocations of eleven events greatly improved the epicenter locations that fall within an area with a radius of about 4 km. The relocated depths are in a range of 8 km to 14 km. According to Shin et al. (2012), the distribution of epicenters and fault plane solution of the largest earthquake in the sequences implied that the earthquake sequences are closely related to the Hupo fault at the eastern margin of Hupo basin. The sequences have been considered to have swarm seismicity pattern. In this study, we analyzed the

  15. 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.

  16. 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.; Johnson, Samuel Y.; 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

  17. 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

  18. 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.

  19. 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.

  20. Greenland unveils terms for offshore licenses

    SciTech Connect

    Not Available

    1992-04-20

    This paper reports that Greenland has spelled out terms for its first round of offshore licensing. The action off western Greenland could lead to the first oil and gas exploration there since an unsuccessful campaign in the 1970s. The Mineral Resources Administration (MRA) for Greenland pegged exploration license terms on 133 blocks, all south of the 66th parallel, at 10 years with options for 2 year extensions to a maximum of 6 more years. The license can cover as many as six blocks. In the first 3 year period companies will have only a seismic obligation of 1,588 km per six blocks. For the second 3 year period there will be a one well obligation and one well in each subsequent 2 year periods.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Personnel evacuation apparatus for an offshore platform

    SciTech Connect

    Hunter, A.F.

    1987-04-28

    An apparatus is described for evacuating personnel from an offshore platform in all weather conditions to a position on the ocean surface a safe distance from the platform the apparatus comprising: a boat launching ramp; flotation means; boat means adapted to be supported and launched by the ramp; means for releasably securing the boat means within the ramp means adjacent the entry end; means for releasing the latch means to permit the flotation means to move the launching ramp from its stowed position to a deployed position; and means for releasing the boat securing means, thereby permitting the boat means to slide down the ramp and be launched from the exit end of the ramp onto the surface of the ocean a safe distance from the platform.

  7. 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.

  8. 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...

  9. 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.

  10. 75 FR 82055 - Commercial Leasing for Wind Power on the Outer Continental Shelf (OCS) Offshore Massachusetts...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ..._Options_Offshore_Wind_12-01-09.pdf . In January 2010, the Executive Office of Energy and Environmental... potential development of offshore wind energy in an ``area of mutual interest'' (AMI) on the OCS offshore... area on the OCS for wind energy projects offshore of Massachusetts will be the evaluation...

  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. 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

  13. Modelling the hydrodynamics of offshore sandbanks

    NASA Astrophysics Data System (ADS)

    Pan, S.; MacDonald, N.; Williams, J.; O'Connor, B. A.; Nicholson, J.; Davies, A. M.

    2007-05-01

    This paper describes the details of a quasi-three-dimensional model (3DBANK), which has been developed to investigate medium and long-term morphological evolution and development of offshore sandbanks. The model is based on a three-dimensional tidal module using the Galerkin-eigenfunction method, but also includes four sub-modules to compute: the instantaneous bedform characteristics from which the temporal and spatial variations of the shear stresses at the sea bed can be derived; the suspended sediment concentration through the water column; the bed-load and suspended sediment fluxes at a point-in-plan; and the resulting morphological changes, respectively. The model also includes the effects of the wind and waves at the sea surface, as well as the wave-current interaction (WCI), and operates with full hydrodynamic and morphodynamic interaction. The components of the model were tested against laboratory and field data, and the complete model was then applied to Middlekerke Bank off the Flemish coast where extensive field measurements were taken during the European Community (EC) funded Circulation and Sediment Transport Around Banks (CSTAB) Project using various advanced instrumentation including STABLE and HF OSCR. Comparisons of the model results with the field measurements and observations show that the model is capable of reproducing the current and wave-induced bedforms, bed roughness, tidal currents and tidal residuals around the sandbank satisfactorily, and can be used to study the long-term sandbank evolution under various offshore conditions. This paper, however, focuses on the hydrodynamic aspects of the model, while the details of the morphological components will be given in a companion paper.

  14. 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.

  15. 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.; Cochrane, Guy R.; Cochran, Susan A.

    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.

  16. 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.

  17. 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.

  18. 26th annual offshore technology conference, 1994 proceedings

    SciTech Connect

    Not Available

    1994-01-01

    This conference is the world's largest and most comprehensive technical conference and exhibition on offshore resource development. The four Proceedings volumes have been separated by major areas of interest, with relative sessions included in each volume. This Volume 3 contains information relative to offshore platforms and marine system designs. It describes both the installation and decommissioning of offshore platforms, retrofitting platforms to meet current safety standards, and technology assessments for both drilling and platform designs. Papers are also provided which describe maintenance and repair technologies for damages to platform.

  19. 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.

  20. Evaluation of offshore penetration tests at El Palito refinery, Venezuela

    SciTech Connect

    Rodriguez, J.I.; Simone, A.; Tichatscheck, C.; Boggess, R.

    1995-12-01

    Data from an offshore study in the western part of Venezuela are presented in terms of the penetration test data and liquefaction evaluation. Two types of penetration test were performed (SPT and DCPT) and the results of each are compared. This was made possible by the comparison testing performed at two different locations where the separation between boreholes with different penetration tests was small enough to allow direct comparison of the results. To the authors` knowledge, this is the first time that dynamic cone measurements have been made in an offshore environment. Comments in relation to the evaluation of liquefaction resistance based on the results of the offshore penetration testing are made.

  1. Devonian shelf basin, Michigan basin, Alpena region

    SciTech Connect

    Gutschick, R.C.

    1986-08-01

    This biostratigraphic study involves the Devonian paleogeography-paleoecology-paleobathymetry of the transition from carbonate platform shelf margin to basinal sedimentation for the northern part of the Michigan basin in the Alpena region. Shelf-basin analysis is based on lithofacies, rock colors, concretion, biostratigraphy, paleoecology of faunas - especially microfaunas and trace fossils - stratified water column, eustasy, and application of Walther's Law. Field observations were made on Partridge Point along Lake Huron, where type sections of the Middle Devonian Thunder Bay Limestone and Late Devonian Squaw Bay Limestone are exposed; and the Antrim black shale at Paxton quarry. The Thunder Bay Limestone evolved as a carbonate platform, subtidal shelf-margin aerobic environment dominated by sessile benthic coralline organisms and shelly fauna, but not reef framework. The Squaw Bay Limestone is transitional shelf to basin, with aspects of slope environment and deeper water off-platform, pelagic organic biostromal molluscan-conodont carbonate deposited during the onset of a stratified water column (dysaerobic benthos-polychaete. agglutinated tubes, sulfides) and pycnocline. The Antrim Shale, in an exceptional black shale exposure in the Paxton quarry, represents deep-water basinal deposition whose bottom waters lacked oxygen. Faunas (conodonts, styliolines, radiolarians) and floras (tasmanitids, calamitids, palynomorphs) are from the aerobic pelagic realm, as indicated from concretions and shale fossil evidence. A benthos is lacking, except for bioturbation from organisms introduced by entrained oxygenated distal turbidite dispersion into the barren bottom black muds. Basinal hydrocarbon source rocks are abundant and updip carbonate reservoirs rim the basin. The Antrim Shale sequence contains the interval of Frasnian-Famennian faunal extinction.

  2. Origin of cratonic basins

    SciTech Connect

    de V. Klein, G.; Hsui, A.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. 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, 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 supercontinent. 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.

  3. Is sinuosity a function of slope and bankfull discharge? - A case study of the meandering rivers in the Pannonian Basin

    NASA Astrophysics Data System (ADS)

    Petrovszki, J.; Timár, G.; Molnár, G.

    2014-11-01

    Pre-regulation channel sinuosities of the meandering rivers of the Pannonian Basin are analysed in order to define a mathematical model to estimate the influence of the bankfull discharge and the channel slope on them. As a primary database, data triplets of slope, discharge and sinuosity values were extracted from historical and modern datasets and pre-regulation historical topographic maps. Channel slope values were systematically modified to estimate figures valid before the river regulation works. The bankfull discharges were estimated from the average discharges using a robust yet complex method. The "classical" graphs of Leopold and Wolman (1957), Ackers and Charlton (1970b) and Schumm and Khan (1972) were compiled to a set up a theoretical surface, whose parameters are estimated by the real values of the above database, containing characteristics of the Pannonian Basin rivers. As a result it occurred that there is a two-dimensional function of the bankfull discharges, which provides a good estimation of the most probable sinuosity values of the rivers with the given slope and discharge characteristics. The average RMS error of this estimation is around 15% on this dataset and believed to be the effect of the non-analysed changes in the sediment discharge and size distribution.

  4. 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.

  5. 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.

  6. 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.

  7. Intra-arc basins

    SciTech Connect

    Smith, G.A.

    1988-01-01

    Convergent-margin tectonic models feature forearc and back-arc basins and generally portray the arc itself as structurally static. However, intra-arc tectonics not only control distribution and petrology of extrusives and plutons, but also generate basins along the magmatic axis. Magma withdrawal and crustal loading by volcanic edifices contribute to subsidence, but most intra-arc basins are grabens or half-grabens indicative of extension. Grabens are isolated or continuous along long segments of the arc. Basin development may alternate with periods of arc uplife. No unique set of conditions causes intra-arc extension; numerous scenarios may initiate extension and subsidence of thermally weakened arc crust. Transtension related to oblique convergence contributed to the formation of most modern intra-arc basins. Andean basins may result from gravitational spreading of an unusually highstanding arc. Intra-arc basin sediment traps may starve arc-adjacent basins from coarse volcaniclastic detritus. Terrestrial intra-arc basins accommodate thick volcanic and volcaniclastic sediment sections, including lacustrine sequences. Marine intra-arc basins include bounding carbonate shelves, marginal and local intrabasinal submarine fans and aprons, and basin plains receiving pelagic and hemipelagic sediments. Structural patterns are appropriate for trapping hydrocarbons, source rocks are commonly present, and high heat flow favors early maturation. Reservoir quality is typically poor because of volcaniclastic diagenesis, but secondary porosity from dissolution of framework feldspars and carbonate or laumontite cements, and the known productivity of some volcanic reservoirs, suggest the potential for hydrocarbon accumulations. Geothermal resources and modest coal potential have also been recognized.

  8. 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.

  9. 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.

  10. OUTSHORE Maturity Model: Assistance for Software Offshore Outsourcing Decisions

    NASA Astrophysics Data System (ADS)

    Mäkiö, Juho; Betz, Stafanie; Oberweis, Andreas

    Offshore outsourcing software development (OOSD) is increasingly being used by the Software Industry. OOSD is a specific variant of Geographically Distributed Software Developmentdistributed software development (GDSD). Compared to the traditional mode of software development (i.e., in-house) GDSD is more edgy and puts at risk the attainment of the expected results. Although the failure of an offshore outsourcing software project may be caused by a variety of factors, one major complication is geographical distance. Consequently we argue that risk avoidance in outshore software development should be undertaken well in advance of the development launch. This could be done by testing the offshore outsourcing relevance of each software project and then the offshore outsourcing company involved. With this in mind we have developed the OUTSHORE Maturity Modeloutshore maturity model - OMM.

  11. “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.

  12. 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.

  13. Onshore-offshore biofacies patterns, Greenhorn eustatic cycle, western interior Cretaceous epicontinental seaway, North America

    SciTech Connect

    Kauffman, E.G.; Sageman, B.B. )

    1990-05-01

    The Cretaceous Western Interior foreland basin provides an ideal testing ground for models of evolution and dispersion among benthic communities. Biological patterns of adaptation, diversity, life habit, population structure, trophic strategies, community composition/structure, and biogeography define biofacies in this epeiric sea. Biofacies distributions are documented for the 6-m.y. Greenhorn eustatic cyclothem (latest Albian-middle Turonian). Two high-resolution cross sections provide a stratigraphic framework: (1) Utah/Arizona to Minnesota, transecting diverse tectonic/sedimentologic provinces within the same warm temperate climatic zone and (2) Alberta to Oklahoma/New Mexico, crossing three biogeographic subprovinces within basinal facies. Plotting biofacies distributions on the cross sections allows the spatial and temporal evolution of Western Interior benthic communities to be studied. Resulting patterns suggest four points. (1) Onshore-offshore and latitudinal trends in shell size, thickness, and ornamentation, community diversity/structure, and the development and dispersion of adaptive characters reflect changes in temperature, benthic oxygen levels, and substrate characteristics. (2) These trends indicate that diverse short-term and long-term oxygen depletion events occurred during Greenhorn deposition, modifying community structure and reflecting dynamic paleooceanographic changes in the seaway. (3) Biofacies/lithofacies data in conjunction with paleogeographic reconstructions allow modeling of community dispersion in response to trends in chemical and physical sedimentologic events. (4) Integration of community data and paleooceanographic models with latest Albian through middle Turonian eustatic history furthers their understanding of the relationship between sea level changes and community evolution in epeiric seas.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Offshore data base shows decline in rig accidents

    SciTech Connect

    Bertrand, A.; Escoffier, L. )

    1991-09-16

    Institut Francais du Petrole (IFP) has compiled statistical figures on offshore accidents for risk, safety, and reliability studies. IFP calls this data base Platform. It provides a body of essential data for accidents concerning both mobile and stationary offshore drilling rigs. Historical accident data bases are a basic implement for risk assessment of safety and reliability. IFP has built this data base with all available information from 950 actual listings.

  20. 2014–2015 Offshore Wind Technologies Market Report

    SciTech Connect

    Smith, Aaron; Stehly, Tyler; Musial, Walter

    2015-09-30

    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.