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1

Atlantic Outer Continental Shelf, Georges Bank: Compilation of Continental Offshore Stratigraphic Test (COST) and Industry Exploration Drilling, 1976-1982.  

National Technical Information Service (NTIS)

Ten wells were drilled offshore from New England on Georges Bank from 1976 through 1982. The first two wells were Continental Offshore Stratigraphic Test (COST) wells, drilled during 1976 and 1977 by energy company consortiums to gain geologic information...

2002-01-01

2

Norwegian Offshore Stratigraphic Lexicon (NORLEX)  

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

3

Controls on sequence development and preservation offshore Namibia: Implications for sequence stratigraphic models and hydrocarbon prediction  

SciTech Connect

Regional seismic interpretation of the passive margin offshore Namibia has enabled a sequence stratigraphic framework to be established for this previously under-studied region. Within this framework potential hydrocarbon plays, for example the location of source, seal and reservoir rocks can be pinpointed. The history of sequence stratigraphic models suggests that the passive margin offshore Namibia should provide an ideal setting for applying and testing sequence stratigraphic concepts. Results from this study however suggest that alongside the documented controls in sequence stratigraphy (i.e. tectonics, eustacy and sediment flux), additional factors act to influence sequence development and preservation along this margin. Detailed seismic interpretation of the post rift section of the Namibian margin has led to the identification of a member of erosional and depositional events; for example, charmers, canyons and slumps. Seismic facies analysis allows causative mechanisms to be inferred for the different geometries observed. In addition, the recognition of characteristic seismic facies enables reservoir and non-reservoir targets to be identified, thus aiding the prediction of potential hydrocarbon plays. Backstripping studies provide further information as to the evolution of the Namibian margin. For example, estimates can be made regarding changes in the rates of tectonics and sedimentation and the relative importance of these factors on the development of the margin can be assessed.

Bagguley, J.G. (Oxford Brookes Univ., Oxford (United Kingdom)); Prosser, S. (Saga Petroleum, Sandvika (Norway))

1996-01-01

4

Sequence stratigraphic framework of Neogene strata in offshore Nigeria  

SciTech Connect

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

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

1996-08-01

5

Simulation modeling of stratigraphic sequences along the Louisiana offshore  

SciTech Connect

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

Kendall, C.G.S.C. (Univ. of South Carolina, Columbia (USA)); Lowrie, A.

1990-09-01

6

Numeric stratigraphic modeling: Testing sequence Numeric stratigraphic modeling: Testing sequence stratigraphic concepts using high resolution geologic examples  

SciTech Connect

Numeric simulations based on integrated data sets enhance our understanding of depositional geometry and facilitate quantification of depositional processes. Numeric values tested against well-constrained geologic data sets can then be used in iterations testing each variable, and in predicting lithofacies distributions under various depositional scenarios using the principles of sequence stratigraphic analysis. The stratigraphic modeling software provides a broad spectrum of techniques for modeling and testing elements of the petroleum system. Using well-constrained geologic examples, variations in depositional geometry and lithofacies distributions between different tectonic settings (passive vs. active margin) and climate regimes (hothouse vs. icehouse) can provide insight to potential source rock and reservoir rock distribution, maturation timing, migration pathways, and trap formation. Two data sets are used to illustrate such variations: both include a seismic reflection profile calibrated by multiple wells. The first is a Pennsylvanian mixed carbonate-siliciclastic system in the Paradox basin, and the second a Pliocene-Pleistocene siliciclastic system in the Gulf of Mexico. Numeric simulations result in geometry and facies distributions consistent with those interpreted using the integrated stratigraphic analysis of the calibrated seismic profiles. An exception occurs in the Gulf of Mexico study where the simulated sediment thickness from 3.8 to 1.6 Ma within an upper slope minibasin was less than that mapped using a regional seismic grid. Regional depositional patterns demonstrate that this extra thickness was probably sourced from out of the plane of the modeled transect, illustrating the necessity for three-dimensional constraints on two-dimensional modeling.

Armentrout, J.M.; Smith-Rouch, L.S. [Mobil Exploration and Producing Technical Center, Dallas, TX (United States); Bowman, S.A. [Marco Polo Software, Inc., Houston, TX (United States)

1996-08-01

7

Seismic stratigraphic analysis of the Punta del Este basin, offshore Uruguay, South America  

SciTech Connect

The Punta del Este part of the greater Salado basin is relatively unexplored with only two wells having been drilled, both in the updip part of the basin. These two wells have contributed some understanding of the stratigraphic succession but have failed to adequately assess the basin's true hydrocarbon potential. This paper constitutes one of the first detailed, comprehensive published accounts of this basin and is a prerequisite for future exploration in the area. In this paper, the authors give the results and major conclusions of a regional seismic stratigraphic analysis of the Punta del Este basin, offshore Uruguay. This paper is one of the first detailed, comprehensive published accounts of the tectonic and sedimentary evolution of this basin. The study area covers approximately 15,000 km{sup 2} (5,790 mi{sup 2}) of the continental shelf, from the shoreline to the 200-m (655-ft) shelf isobath.

Stoakes, F.A.; Campbell, C.V. (Stoakes Campbell Geoconsulting Ltd., Calgary, Alberta (Canada)); Cass, R. (Arvec Consulting Ltd., Calgary, Alberta (Canada)); Ucha, N. (ANCAP, Montivideo (Uruguay))

1991-02-01

8

Sequence stratigraphic applications to deep-water exploration in the Makassar Strait, offshore East Kalimantan, Indonesia  

SciTech Connect

A sequence stratigraphic study was conducted to help evaluate the exploration potential of the Makassar PSC, offshore East Kalimantan, Indonesia. The PSC is on the present-day slope in water depths of 500-3000 ft and borders the large oil and gas fields of the Mahakam delta. The study provided important insights on reservoir distribution, trapping style, and seismic hydrocarbon indicators. Lowstand deposition on a slope modified by growth faulting and shale diapirism controlled reservoir distribution within the prospective late Miocene section. Three major lowstand intervals can be seismically defined and tied to deep-water sands in nearby wells where log character and biostratigraphic data support the seismic system tract interpretation. The three intervals appear to correlate with third-order global lowstand events and are consistent with existing sequence stratigraphic schemes for the shelf and upper slope in the Makassar area. Seismic mapping delineated lowstand features, including incised valleys and intraslope to basin-floor thicks. Regional information on positions of middle-late Miocene delta lobes and shelf edges, helped complete the picture for sand sources, transport routes, and depocenters.

Malacek, S.J.; Reaves, C.M.; Atmadja, W.S.; Widiantara, K.O. (Mobil Oil Indonesia, Jakarta (Indonesia))

1994-07-01

9

Offshore well test platform system  

Microsoft Academic Search

This patent describes an offshore well test platform system positionable above one or more underwater wells. It comprises: a submergible buoy to be restrained below the surface of the water and above one or more underwater wells; a platform structure connectable to the buoy and having an upper portion extending above the surface of the water when connected to the

H. Chiu; D. K. Nelsen

1990-01-01

10

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

NASA Astrophysics Data System (ADS)

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 established in the Malvinas Basin during the Paleocene to early Eocene. This period was accompanied by the development of a deep sedimentary trough in the south. Extension was possibly related to the opening of the Drake Passage or to lithospheric flexure and bending. Structures mainly consist of reactivated normal faults, strike-slip faults and some minor reverse faults. The units U5a and U5b (42.5-5.5 and 5.5-0 Ma, transpressional foredeep phase) represent a stratigraphic switch from aggradation to progradation. While on the west of the basin downlapping clinoforms prograding eastwards are present, a northward onlapping wedge is identified in the deeper southern part of the basin. During this time, the sediment supply was considerably higher. The entire basin was filled and the depocenter migrated southeastwards. The tectonic regime changed to compression and later during the Oligocene to transpression, developing a major sinistral transpressional fault in the south of the basin. In summary, the basin developed initially as a Mesozoic rift basin which switches to a foreland basin with a sinistral wrench component and increased sediment input in the south during the Cenozoic.

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

2012-04-01

11

Offshore well test platform system  

SciTech Connect

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

Chiu, H.; Nelsen, D.K.

1990-03-06

12

Sequence stratigraphic analysis of an unstable shelf margin: An example from Miocene section of offshore western Louisiana, Gulf of Mexico  

SciTech Connect

Sequence stratigraphic analysis using seismic baselap terminations is not usually applicable to the Miocene section of offshore western Louisiana, Gulf of Mexico, because of the lack of identifiable baselap and expansion at growth faults. Identification of condensed sections, which usually occur at the top of the transgressive systems tracts and are easily identifiable marker beds in nannofossil, well log, and seismic data, is an alternative approach to sequence stratigraphic analysis. Integrated interpretation of high-resolution calcareous nannofossil abundance data from nine wells, 91 paleontological reports (foraminifera), well log data from 73 wells, and more than 2,400 mi of seismic data defines seven genetic stratigraphic sequences and corresponding systems tracts from the late Early Miocene through the early Pliocene. The highstand systems tracts are dominant on the shelf and slop in the study area. The transgressive systems tracts are rather thin. The lowstand systems tracts are usually limited on the downthrown sides of major growth faults except for a thick lowstand prograding wedge of the Ampbistegina B-Discorbis B sequence deposited on the shelf and slope. The seismic amplitudes of highstand systems tracts are moderate to variable in the updip area and low in the downdip area. The seismic attributes of transgressive systems tracts are moderate amplitude, high frequency, and moderate to high community. The condensed section exhibits a strong reflection. Seismic attributes of lowstand systems tracts are low amplitude and low continuity, and sometimes a hummocky pattern.

Yang, S.Y.; Watkins, J.S. (Texas A and M Univ., College Station (United States))

1991-08-01

13

Tectono-stratigraphic signature of multiphased rifting on divergent margins (deep-offshore southwest Iberia, North Atlantic)  

NASA Astrophysics Data System (ADS)

Regional 2D multichannel seismic, borehole, dredge and outcrop data, together with burial models for strata in southwest Iberia, are used to investigate the tectono-stratigraphic signature of multiphased rifting on divergent margins. Our burial model reveals that Mesozoic extension occurred during three main phases, each comprising distinct subsidence pulses separated by short-lived periods of crustal uplift. The importance of the three phases varies across discrete sectors of the margin, each one revealing similar depositional architectures and associated tectonic systems tracts: 1) the Rift Initiation phase, characterized by incipient subsidence and overall aggradation/progradation over a basal unconformity, 2) the Rift Climax phase, which marks maxima of tectonic subsidence and is characterized by retrogradation-progradation, and 3) the Late Rift phase, recording the progradational infill of the basin and the effects of eustasy. The Rift Initiation systems tracts comprise Sinemurian and late Callovian-early Oxfordian strata. Marine units in the Pliensbachian and Late Oxfordian-Kimmeridgian represent the Rift Climax phase, a period marked by the development of Maximum Flooding Surfaces. Late Rift deposits were identified in the Rhaetian-Hettangian, Toarcian-Bathonian and Kimmeridgian-Berriasian. The results of this work are important to the economic exploration of deep-offshore rift basins, as they reveal that sequence stratigraphy can be used to predict sedimentary facies distribution in more distal segments of such basins. Significantly, this work recognizes that multiple tectonic-stratigraphic (rift) cycles can occur on deep-offshore rift basins, from the onset of rift-related extension until continental break-up, a character that contrast to what is known from deep-sea drilling data from the distal margin of Northwest Iberia.

Pereira, Ricardo; Alves, Tiago M.

2012-08-01

14

Coupled stratigraphic and structural evolution of a glaciated orogenic wedge, offshore St. Elias orogen, Alaska  

NASA Astrophysics Data System (ADS)

The St. Elias orogen is the result of ˜10 Myr of oblique convergence and flat-slab subduction in the Gulf of Alaska between North America and the Yakutat microplate. Extensive glaciation and a complex tectonic environment make this region a unique case study in which to examine the details of terrane accretion and the possible coupled influence of climate and tectonic drivers on the structural and topographic evolution of an orogenic wedge. Reflection seismic profiles across the offshore Pamplona zone fold-thrust belt, the frontal St. Elias orogenic wedge, provide constraints for quantifying Pleistocene deformation recorded in the glaciomarine Yakataga formation. The total amount of Pleistocene shortening observed varies from ˜3 to 5 mm/yr, compared to the current GPS-derived Yakutat-North America convergence rate across the St. Elias orogen of ˜45 mm/yr. Growth strata and kinematic fold analysis allow comparison of relative timing of fault activity, which reveals temporal and spatial shifting of active deformation during the glacial period: faulting localized adjacent to the coastline and at the current submarine deformation front. The abandoned, currently inactive region is colocated with the major glacial depocenter in the region, the Bering Trough. These observations imply that glacial processes such as sediment loading and focused erosion during advance-retreat cycles has a direct effect on the evolution of individual faults within the Pamplona zone and the overall deformation pattern in the offshore St. Elias margin. This information provides key constraints for understanding how climatic shifts may have affected the evolution of margin architecture during Pleistocene glacial-interglacial periods.

Worthington, Lindsay L.; Gulick, Sean P. S.; Pavlis, Terry L.

2010-12-01

15

Seismic and Gravity Data Help Constrain the Stratigraphic and Tectonic History of Offshore New Harbor, Ross Sea, Antarctica  

NASA Astrophysics Data System (ADS)

The ANDRILL (ANtarctic geological DRILLing) Program’s Offshore New Harbor (ONH) Project successfully conducted multi-channel seismic and gravity surveys in 2008 to investigate the stratigraphic and tectonic history of westernmost Southern McMurdo Sound, Ross Sea, Antarctica, during the Greenhouse World (Eocene) into the start of the Icehouse World (Oligocene). Approximately 48 km of multi-channel seismic reflection data were collected on a sea-ice platform east of New Harbor. The seismic survey used and improved upon methods employed successfully by ANDRILL’s surveys in Southern McMurdo Sound (2005) and in Mackay Sea Valley (2007). These methods include using an air gun and snow streamer of gimbaled geophones. Upgrades in the ONH project’s field equipment substantially increased the rate at which seismic data could be acquired in a sea-ice environment compared to all previous surveys. In addition to the seismic survey, gravity data were collected from the sea ice in New Harbor with the aim of defining basin structural controls. Both the seismic and gravity data indicate thick sediment accumulation above the hanging wall of a major range front fault. This clearly identified fault could be the postulated master fault of the Transantarctic Mountains. An approximately 5 km thick sequence of sediments is present east of the CIROS-1 drill hole. CIROS-1 was drilled adjacent to the range front fault and recovered 702 m of sediments that cross the Eocene/Oligocene boundary. The new geophysical data indicate that substantial sediment core below the Eocene/Oligocene boundary could be recovered to the east of CIROS-1 during future drilling. Inshore of the range front fault, the data show fault bounded half grabens with sediment fill thickening eastward against localized normal faults. Modeling of the gravity data, that extends farther inland than the seismic profiles, suggests that over 1 km of sediments could be present locally offshore Taylor Valley. Future drilling of offshore Taylor Valley could help to constrain the East Antarctic Ice Sheet’s contributions to glacial-interglacial cyclicity in southern McMurdo Sound as far back as the middle Miocene. Unfortunately, the 2008 ONH seismic profiles do not extend far enough up Taylor Valley or Ferrar Fjord to fully define drilling targets. As a result, valley parallel seismic profiles are proposed to extend our seismic interpretations inland and substantiate the gravity models.

Speece, M. A.; Pekar, S. F.; Wilson, G. S.; Sunwall, D. A.; Tinto, K. J.

2010-12-01

16

Alaska Gas Hydrate Research and Stratigraphic Test Preliminary Results  

Microsoft Academic Search

Gas hydrate may contain significant gas resources in both onshore arctic and offshore regions throughout the world. The BP-DOE collaborative research project is designed to help determine whether or not gas hydrate can become a technically and economically recoverable gas resource. Reservoir characterization, development scenario modeling, and associated studies indicated that 0-0.34 Trillion Cubic Meters (0-12 Trillion Cubic Feet -

Robert B. Hunter; Scott A. Digert; Ray Boswell; Timothy S. Collett

17

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

NASA Astrophysics Data System (ADS)

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

Gomez-Cabrera, Pedro Tomas

2003-10-01

18

Quantitative seismic attribute analysis using artificial neural networks and seismic stratigraphic interpretation of lower to middle Miocene sediments offshore New Jersey  

NASA Astrophysics Data System (ADS)

This study comprises two parts intended to improve understanding of the lower and middle Miocene depositional history of the New Jersey continental shelf. The first, lower Miocene-based part, aims to determine lateral variations in lithofacies between holes drilled by IODP Expedition 313 using seismic attributes and artificial neural networks. The second provides detailed seismic sequence stratigraphy of mid-Miocene successions. Neural networks are used in the first part to search for a relationship between seismic attributes and gamma log measurements of the lower Miocene section. Using this relationship, the networks generate 'pseudo gamma logs' that predict lateral changes in lithofacies based on accompanying changes in seismic attributes. A successful test of the technique is demonstrated using 3D seismic data and 6 closely-spaced gamma ray logs from the Denver Basin. A similar application to lower Miocene successions offshore NJ is unsuccessful, most likely due to an insufficient number of wells, complexity of lithofacies variations between wells up to 12 km apart, and/or an incorrect selection of attributes. In the second part, candidate sequence boundaries are identified in a grid of high-resolution, densely spaced profiles. In addition to a more detailed history than derived from prior studies, this part reveals previously unreported records of sediment erosion and possible global climate influence on the middle Miocene stratigraphic evolution offshore New Jersey. Eleven candidate sequence boundaries, three not documented by previous studies, are identified. System tract positions of each sequence are determined, while only one transgressive system tract and no lowstand fans are observed. Age estimates based on published studies show that the 11 mid Miocene sequences reported here span the interval between ˜11.8-12.9 Ma, suggesting an average interval between each of 100 kyr. Clinoform rollovers prograded SE during the development of the oldest sequence of the study area beginning at a time that coincides with a major shift in ?18O towards heavier values (represented by Mi4) and at about the time of the permanent East Antarctic ice sheet development. Grain size distribution of the prograding clinoforms is predicted by extrapolating IODP Expedition 313’s lithostratigraphic analysis of lower Miocene succession.

Karakaya, Sarp

19

Constructing Stratigraphic Relationships Using Secondary Craters: A Lunar Test Case  

NASA Astrophysics Data System (ADS)

Secondary cratering is a possible contaminant of small crater distributions used to date young terrains in the Solar System. As such, much attention has been paid to identifying the effect of the secondary population on the cratering record of various bodies. Our technique utilizes 100m resolution circular polarization ratio (CPR) maps generated from 2.38 GHz Arecibo radar data of the lunar South Pole to distinguish secondary craters from small primaries at large distances from the primary impact. High levels of CPR are indicative of blocky ejecta tails and can be used not only to identify secondaries in this "far field” regime, but can also indicate the associated primary crater by the tail direction. We apply this method to a region on the floor of Newton-A crater ( 60 km diameter), where our refined counts identify 56 secondary craters with diameters above 400m (43.8% of the total population) associated with the primary crater Tycho (85 km diameter)—some 1000 km to the north. In addition to providing information on the relative importance of secondary and primary craters at small diameters, this method of secondary crater identification provides valuable information about the terrains on which they are emplaced. Secondary craters associated with a single primary event form simultaneously, therefore serving as a convenient layer around which stratigraphic relationships can be constructed—particularly if the age of the primary is well constrained. For extensive secondary networks, the semi-global reach of this layer provides a way to compare in a standardized way terrain units separated by thousands of kilometers. As a demonstration of this technique, we employ a combination of crater morphology and CPR tail analysis to determine the ages of features on the floor of Newton-A relative to the layer of Tycho secondaries present there. Funding by NASA's Planetary Astronomy program is acknowledged.

Wells, Kassandra; Campbell, D. B.; Campbell, B. A.; Carter, L. M.

2008-09-01

20

59 FR- Draft NPDES General Permit for Offshore Oil and Gas Operations on the Outer Continental Shelf...  

Federal Register 2010, 2011, 2012, 2013

...Draft NPDES General Permit for Offshore Oil and Gas Operations on the Outer Continental...Elimination System (NPDES) general permit for oil and gas stratigraphic test and exploration...Arctic general permit will authorize offshore oil and gas stratigraphic test and...

1994-09-20

21

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

Microsoft Academic Search

Microfacies analysis of marine carbonates cored by Petrobras well 1-SPS-6 in the offshore Santos Basin (southeastern Brazil) has revealed a remarkable fossil assemblage of calpionellids (colomiellids), favusellids, hedbergellids, globigerinelloidids, buliminids, radiolarians, inoceramid prisms, roveacrinids, and saccocomids(?) preserved in lower Albian calcimudstones–wackestones of the lower part of the Guarujá Formation. This assemblage represents an allochtonous accumulation in a deep neritic to

D. Dias-Brito; B Ferré

2001-01-01

22

Selected stratigraphic data for drill holes located in Frenchman Flat, Nevada Test Site. Rev. 1  

SciTech Connect

Stratigraphic data are presented in tabular form for 72 holes drilled in Frenchman Flat, Nevada Test Site, between 1950 and 1993. Three pairs of data presentations are included for each hole: depth to formation tops, formation thicknesses, and formation elevations are presented in both field (English) and metric units. Also included for each hole, where available, are various construction data (hole depth, hole diameter, surface location coordinates) and certain information of hydrogeologic significance (depth to water level, top of zeolitization). The event name is given for holes associated with a particular nuclear test. An extensive set of footnotes is included, which indicates data sources and provides other information. The body of the report describes the stratigraphic setting of Frenchman Flat, gives drill-hole naming conventions and database terminology, and provides other background and reference material.

Drellack, S.L. Jr.

1997-02-01

23

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

Microsoft Academic Search

The Mount Elbert Gas Hydrate Stratigraphic Test Well was drilled within the Alaska North Slope (ANS) Milne Point Unit (MPU) from February 3 to 19, 2007. The well was conducted as part of a Cooperative Research Agreement (CRA) project co-sponsored since 2001 by BP Exploration (Alaska), Inc. (BPXA) and the U.S. Department of Energy (DOE) in collaboration with the U.S.

Robert B. Hunter; Timothy S. Collett; Ray Boswell; Brian J. Anderson; Scott A. Digert; Gordon Pospisil; Richard Baker

2011-01-01

24

Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Coring operations, core sedimentology, and lithostratigraphy  

Microsoft Academic Search

In February 2007, BP Exploration (Alaska), the U.S. Department of Energy, and the U.S. Geological Survey completed the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well (Mount Elbert well) in the Milne Point Unit on the Alaska North Slope. The program achieved its primary goals of validating the pre-drill estimates of gas hydrate occurrence and thickness based on 3-D seismic

Kelly Rose; Ray Boswell; Timothy Collett

2011-01-01

25

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

26

Neogene and Quaternary geology of a stratigraphic test hole on Horn Island, Mississippi Sound  

USGS Publications Warehouse

During April and May, 1991, the U.S. Geological Survey (USGS) drilled a 510-ft-deep, continuously cored, stratigraphic test hole on Horn Island, Mississippi Sound, as part of a field study of the Neogene and Quaternary geology of the Mississippi coastal area. The USGS drilled two new holes at the Horn Island site. The first hole was continuously cored to a depth of 510 ft; coring stopped at this depth due to mechanical problems. To facilitate geophysical logging, an unsampled second hole was drilled to a depth of 519 ft at the same location.

Gohn, Gregory S.; Brewster-Wingard, G. Lynn; Cronin, Thomas M.; Edwards, Lucy E.; Gibson, Thomas G.; Rubin, Meyer; Willard, Debra A.

1996-01-01

27

Tests prove two-phase efficiency for offshore pipeline  

SciTech Connect

Tests prior to the conversion of the Matagorda Offshore Pipeline System (MOPS) from single-phase flow to two-phase flow revealed the weakness of many generalized theories and correlations when applied to large (20-30 in.) pipelines. Northern Natural Gas (NNG) Co., operator of the south Texas line, set up the procedures and conducted the tests that led to this observation.

Schweikert, L.E.

1986-02-03

28

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

USGS Publications Warehouse

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

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

2011-01-01

29

Distorted polyester lines for model testing of offshore moored platforms  

Microsoft Academic Search

Model tests of floating offshore platforms replace the mooring lines by inextensible cables connected to steel springs with a linear restoring capability. With the help of fundamental investigation on the similarity laws, the present work shows that the use of very thin polyester lines in model scaling is feasible and may allow a better physical representation of the full-scale polyester

A. C. Fernandes; R. R. Rossi

2005-01-01

30

Dynamic Response of a Mobile Offshore Base Hydroelastic Test Model.  

National Technical Information Service (NTIS)

The objective of the work presented in this thesis deals with the study of dynamic response of a Mobile Offshore Base (MOB) hydroelastic test model. The MOB is a very large floating structure consisting of multiple self- propelled. semi-submersible module...

V. Venkataraman

2001-01-01

31

Tectonic reconstructions of the southwestern Great Basin: Stratigraphic tests of structural models  

SciTech Connect

Accurate paleogeographic reconstruction of the tectonically dismembered southwestern Great Basin is in large part dependent on the validity of the Wernicke et al. (1988) and Snow and Wernicke (1989) correlations of Mesozoic (pre-Tertiary) contractile deformational features. In order to independently assess these structurally based models and their predictions, carefully chosen stratigraphic data were used as tests. In the northern Death Valley region, sediment dispersal trends in two regionally developed facies of the Lower Cambrian Wood Canyon Formation and Zabriskie Quartzite suggest that otherwise uniformly northwest-directed paleocurrent indicators have undergone vertical axis rotations comparable in direction and magnitude to those predicted for anti-clockwise rotation of the Grapevine Mountains structural block. In the central Death Valley region, stratigraphic differences in upper plate rocks in the proposed Tucki Mountain-northern Nopah Range pierce point prevent the adjacent juxtaposition of those rocks but are permissive of such a correlation. Finally, in the southern Death Valley region, the Levy and Christie-Blick (1989) pre-Mesozoic reconstruction results in overlap of range blocks and juxtaposition of disparate facies in the Proterozoic Pahrump Group rocks. This implies that the Cenozoic deformational vector displacement paths, determined for elsewhere in the southern Great Basin, are not applicable to southern Death Valley and must be reassessed.

Prave, A.R. (City College of New York, NY (United States). Dept. of Earth and Atmospheric Sciences); Snow, J.K. (California Inst. of Technology, Pasadena, CA (United States). Division of Geology and Planetary Sciences)

1993-04-01

32

Test evaluates high-volume ESP application offshore Mexico  

Microsoft Academic Search

An electric submersible pump (ESP) test, although shorter than hoped for, indicated that artificial lift with ESPs had potential for replacing gas-lift operations, offshore Mexico. Petroleos Mexicanos (Pemex) recently preformed this test of a high-volume (10,000 b\\/d) ESP in the Akal reservoir of the Cantarell field, northeast Marina Region in the Gulf of Mexico. In the Marine Region, gas lift

S. G. Almazo; G. Riling

1998-01-01

33

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

USGS Publications Warehouse

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

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

2011-01-01

34

Digital offshore radio system to be tested  

SciTech Connect

Tests on a digital selective calling marine communications system that is to be examined by the International Maritime Organization (IMO) this year are described. The new system, designed to operate routinely on VHF frequency, will create a new era for marine communications. A land-based frequency management computer will screen emergency and routine calls while also automatically switching to frequencies offering the best field strength. The computer will automatically change frequencies. The operator will never know what frequency he is using. The network also will include a direct printing unit operating on 518 kilocycles. The printer will continually provide the ship or rig with weather reports and navigational warnings.

Not Available

1985-04-01

35

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

SciTech Connect

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

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

1996-01-01

36

Test evaluates high-volume ESP application offshore Mexico  

SciTech Connect

An electric submersible pump (ESP) test, although shorter than hoped for, indicated that artificial lift with ESPs had potential for replacing gas-lift operations, offshore Mexico. Petroleos Mexicanos (Pemex) recently preformed this test of a high-volume (10,000 b/d) ESP in the Akal reservoir of the Cantarell field, northeast Marina Region in the Gulf of Mexico. In the Marine Region, gas lift is the main artificial lift method; however, to maintain production on gas lift, sweetened gas requirements for the Akal reservoir would have to increase by about 30 MMscfd. The ESP design was complex because the pump would have to handle 20--40% of free gas at its intake. Installed in September 1996, the ESP had to be pulled from the well in November 1997 because of an electrical short. Actual operating time was about 7 months. The paper describes test objectives, pump environment, pump design, downhole equipment, surface equipment, operating history, production history, and an analysis.

Almazo, S.G. [Pemex, Villahermosa (Mexico); Riling, G. [Cealc, Bartlesville, OK (United States)

1998-02-16

37

Offshore filtration testing and analysis of seawater for oil-field injection  

Microsoft Academic Search

A high rate media-type filter developed for water injection applications has been tested on a 400 BWPD (barrels of water per day) pilot plant to gather data on water quality achievable on equipment practical for offshore oil production installations. This work has been spread over 13 offshore locations around the world in seven different seas that represent a wide variety

J. B. Cappi; H. R. Blagden

1981-01-01

38

Large Scale Service Loading Fatigue Testing with Particular Reference to Offshore Structures.  

National Technical Information Service (NTIS)

A range of tests on welded steel tubular joints, as used in offshore jacket platforms, and parallel work on simpler cruciform welded joints are described. Testing in a seawater environment and the effect of various random loading stress histories appropri...

K. J. Marsh

1980-01-01

39

Characterizing Structural and Stratigraphic Heterogeneities in a Faulted Aquifer Using Pump Tests with an Array of Westbay Multilevel Monitoring Wells  

NASA Astrophysics Data System (ADS)

We are developing and assessing field testing and analysis methodologies for quantitative characterization of aquifer heterogenities using data measured in an array of multilevel monitoring wells (MLW) during pumping and recovery well tests. We have developed a unique field laboratory to determine the permeability field in a 20m by 40m by 70m volume in the fault partitioned, siliciclastic Hickory aquifer system in central Texas. The site incorporates both stratigraphic variations and a normal fault system that partially offsets the aquifer and impedes cross-fault flow. We constructed a high-resolution geologic model of the site based upon 1050 m of core and a suite of geophysical logs from eleven, closely spaced (3-10m), continuously cored boreholes to depths of 125 m. Westbay multilevel monitoring systems installed in eight holes provide 94 hydraulically isolated measurement zones and 25 injection zones. A good geologic model is critical to proper installation of the MLW. Packers are positioned at all significant fault piercements and selected, laterally extensive, clay-rich strata. Packers in adjacent MLW bracket selected hydrostratigraphic intervals. Pump tests utilized two, uncased, fully penetrating irrigation wells that straddle the fault system and are in close proximity (7 to 65 m) to the MLW. Pumping and recovery transient pressure histories were measured in 85 zones using pressure transducers with a resolution of 55 Pa (0.008 psi). The hydraulic response is that of an anisotropic, unconfined aquifer. The transient pressure histories vary significantly from zone to zone in a single MLW as well as between adjacent MLW. Derivative plots are especially useful for differentiating details of pressure histories. Based on the geologic model, the derivative curve of a zone reflects its absolute vertical position, vertical stratigraphic position, and proximity to either a fault or significant stratigraphic heterogeneity. Additional forward modeling is needed to assist qualitative interpretation of response curves. Prior geologic knowledge appears critical. Quantitative interpretation of the transient pressure histories requires utilizing a numerical aquifer response model coupled with a geophysical inversion algorithm.

Johnson, B.; Zhurina, E. N.

2001-12-01

40

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

EPA Science Inventory

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

41

Gas-Charged Sediments Within the Hyblean Plateu Seismo-Stratigraphic Sequence and Associated Likely Shallow Mud-Volacanoes Seafloor Features Offshore Southern Sicily (Sicily Channel - Mediterranean Sea)  

NASA Astrophysics Data System (ADS)

A shallow province of small-scale likely mud-volcanoes (MVs) seafloor features was recently discovered few miles offshore south-eastern Sicily (Holland et al., 2003) over the Hyblean-Malta plateau (Sicily-channel - Mediterranean sea), on an area whose surface might be over 100 square km and in a bathymetric range comprised between -100 and -200m. Such discovery promoted the National multidisciplinary programm MESC (Mud volcanoes Ecosystem study - Sicily Channel) aimed to provide a detailed acoustic mapping of the area (Savini et al., 2006) and focused water and sediment samples to study the ecosystem response to such geological phenomena. The main data set thus collected, during three different cruises carried out by the Italian R/V UNIVERSITATIS by mean of acoustic survey techniques, including new multibeam bathymetric data, side- scan sonar mosaics, a dense network of chirp-sonar profiles and focused multi-tip sparker profiles, is here presented. The detailed seafloor topography and the side scan sonar mosaic well show the occurrence of a field of more than 100 small scale conical and sub-conical seabed features, few meters high. Their morphologies, their strong acoustic scattering and the presence over them of distinct gas plumes, are foremost distinctive proprieties that liken them to MVs. Such filed consists of single and composite MVs arranged on the seafloor in two main different styles: 1) several conical features 50 - 200m in diameter, preferentially aligned along the isobaths 2) numerous close-set small cones no more than 10m in diameter, settled within well defined, flat, elongated areas (the largest one reaches 2000m in its long axis and 500m in its short axis) rising up to 10m from the seafloor. The acoustic character of the sediments in the chirp and sparker records indicates that such features are gas charged, because of the presence of numerous acoustic anomalies (i.e.: acoustic turbidity zones, wipe outs, gas pockets, enhanced reflectors...). In particular, the identified gas-related seafloor features are associated to sub- surface structures formed within a gas accumulative horizon covered by a variable thickness of sediments. This gas accumulative horizon has been found in association to a marked unconformity resembles the last trasgressive surface at the boundary between the Holocene and the Pleistocene sediments. Such gas-charged horizon has been used to map the depth of the free gas within the seafloor sediments. The depth of this "gas- front" is variable and domes up to the seafloor where MVs morphologies are found at the surface, often showing gas plumes (up to 20m high) at their top.

Savini, A.; Tessarolo, C.; Corselli, C.

2007-12-01

42

Offshore next generation weather radar (NEXRAD) test and evaluation master plan (TEMP)  

Microsoft Academic Search

This document provides the test philosophy and approach for the Offshore Next Generation Weather Radar (NEXRAD) Test and Evaluation Master Plan (TEMP). The NEXRAD differs from the typical Federal Aviation Administration (FAA) weather radar acquisition in that it is jointly funded by the Department of Defense (DOD), the Department of Commerce (DOC), and the Department of Transportation (DOT). These three

Radame Martinez; Robert Cranston; John Porcello

1995-01-01

43

First quantitative test of alluvial stratigraphic models: Southern Rio Grande rift, New Mexico  

Microsoft Academic Search

Since 1978 the results of computational architectural models have been widely used to aid interpretation of ancient alluvial successions: here we present the first quantitative test of such models. We parameterize variables from field and magnetostratigraphic data collected from the well-exposed Pliocene-Pleistocene Camp Rice and Palomas Formations of the Rio Grande rift in south-central New Mexico. Computational runs establish that

Mike R. Leeder; Greg H. Mack; Jeff Peakall; Stephen L. Salyards

1996-01-01

44

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

SciTech Connect

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

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

2008-01-01

45

First quantitative test of alluvial stratigraphic models: Southern Rio Grande rift, New Mexico  

NASA Astrophysics Data System (ADS)

Since 1978 the results of computational architectural models have been widely used to aid interpretation of ancient alluvial successions: here we present the first quantitative test of such models. We parameterize variables from field and magnetostratigraphic data collected from the well-exposed Pliocene-Pleistocene Camp Rice and Palomas Formations of the Rio Grande rift in south-central New Mexico. Computational runs establish that the LAB (Leeder, Allen, and Bridge) model correctly predicts the gross architectural patterns of ancestral axial Rio Grande half grabens and full grabens. Convergence of tectonic subsidence rate and mean sedimentation rate over the studied interval suggests that the dynamic basis of the models is correct; i.e., it is the tectonic “drawdown” of axially supplied sediment that controls the net preservation potential of alluvial successions.

Leeder, Mike R.; Mack, Greg H.; Peakall, Jeff; Salyards, Stephen L.

1996-01-01

46

Stratigraphic and palaeoenvironmental summary of the south-east Georgia Embayment: a correlation of exploratory wells  

USGS Publications Warehouse

A Continental Offshore Stratigraphic Test (COST) well and six exploratory wells have been drilled in the south-east Georgia embayment. The oldest rocks penetrated are weakly metamorphosed Lower Ordovician quartz arenites and Silurian shales and argillites in the Transco 1005-1 well and Upper Devonian argillites in the COST GE-1 well. The Palaeozoic strata are unconformably overlain by interbedded non-marine Jurassic sandstones and shales and marginal marine Lower Cretaceous rocks. Together, these rocks are stratigraphically equivalent to the onshore Fort Pierce and Cotton Valley(?) Formations and rocks of the Lower Cretaceous Comanchean Provincial Series. The Upper Cretaceous part of the section is composed mainly of neritic calcareous shales and shaley limestones stratigraphically equivalent to the primarily marginal marine facies of the onshore Atkinson, Cape Fear and Middendorf Formations and Black Creek Group, and to limestones and shales of the Lawson Limestone and Peedee Formations. Cenozoic strata are also described. -from Authors

Poppe, L. J.; Popenoe, P.; Poag, C. W.; Swift, B. A.

1995-01-01

47

Synthetic “mud ropes” for offshore mooring applications - field history and testing data  

Microsoft Academic Search

With the continuing development of synthetic ropes and real-world experience gained through their use in offshore mooring operations, it is evident that previous reservations about the use of synthetics in soils are no longer warranted. This is proven through the extensive documentation of field service history, coupled with rope and fiber testing of a jointly developed High Modulus Polyethylene (HMPE)

Jason D. Pasternak; John Shelton; Justin Gilmore

2011-01-01

48

Offshore next generation weather radar (NEXRAD) test and evaluation master plan (TEMP)  

NASA Astrophysics Data System (ADS)

This document provides the test philosophy and approach for the Offshore Next Generation Weather Radar (NEXRAD) Test and Evaluation Master Plan (TEMP). The NEXRAD differs from the typical Federal Aviation Administration (FAA) weather radar acquisition in that it is jointly funded by the Department of Defense (DOD), the Department of Commerce (DOC), and the Department of Transportation (DOT). These three agencies chartered the Joint System Program Office (JSPO) to manage the NEXRAD development and subsequent test programs. JSPO has deployed 70 single-channel radar systems across the continental United States (CONUS). The FAA is deploying NEXRAD systems at non-CONUS (offshore) locations such as Alaska, Hawaii, and the Caribbean. The FAA Offshore NEXRAD will have a redundant configuration and a Remote Monitoring Subsystem (EMS). A total of 14 Offshore NEXRAD's will be procured under this acquisition: 3 in the Caribbean, 4 in Hawaii, and 7 in Alaska. Funding constraints will limit the acquisition to seven NEXRAD's in the 1994-1995 timeframe.

Martinez, Radame; Cranston, Robert; Porcello, John

1995-01-01

49

Geophysical, stratigraphic, and flow-zone logs of selected test, monitor, and water-supply wells in Cayuga County, New York  

USGS Publications Warehouse

Volatile-organic compounds have been detected in water sampled from more than 50 supply wells between the City of Auburn and Village of Union Springs in Cayuga County, New York, and the area was declared a Superfund site in 2002. In 2001-04, geophysical logs were collected from 37 test, monitor, and water-supply wells as a preliminary part of the investigation of volatile-organic compound contamination in the carbonate-bedrock aquifer system. The geophysical logs included gamma, induction, caliper, wellbore image, deviation, fluid resistivity and temperature, and flowmeter. The geophysical logs were analyzed along with core samples and outcrops of the bedrock to define the stratigraphic units and flow zones penetrated by the wells. This report describes the logging methods used in the study and presents the geophysical, stratigraphic, and flow-zone logs.

Anderson, J. Alton; Williams, John H.; Eckhardt, David A. V.; Miller, Todd S.

2003-01-01

50

Investigation in the readability and reliability of Basic Offshore Safety and Emergency (B.O.S.E.T) test  

Microsoft Academic Search

This paper presents the development of a Basic Offshore Safety and Emergency Training (B.O.S.E.T) knowledge test. The knowledge test is a research tool that is meant to measure B.O.S.E.T knowledge retention among offshore professionals. The objective of this paper is to validate a research tool by using key test elements such as validity, reliability and readability. The knowledge test was

Mohamad Fahmi Bin Hussin; Siti Zaliha Mohammad Noor; Bin Wang; Ramani Hipnie

2011-01-01

51

Sentinel Hill Core Test 1: Facies Descriptions and Stratigraphic Reinterpretations of the Prince Creek and Schrader Bluff Formations, North Slope, Alaska  

USGS Publications Warehouse

The Sentinel Hill Core Test 1 well penetrated an intertonguing sequence of (1) the marine Schrader Bluff Formation in the depth intervals 950?1,180 ft and 690?751 ft, which consists of shoreface and offshore deposits that accumulated along a storm-dominated, barred shoreline; and (2) the nonmarine Prince Creek Formation in the depth intervals 751?950 ft and surface to 690 ft, which consists of fluvial channel, crevasse splay, backswamp, and ash fall deposits. The strata range in age from early Campanian to early Maastrichtian. An erosional contact at a depth of 690 ft at the base of the upper unit of the Prince Creek Formation is interpreted as a major regional sequence boundary, and the overlying conglomeratic fluvial channel deposits are interpreted to have accumulated in a paleovalley. In its more proximal reaches along the Colville River, channels of this paleovalley cut down 75 ft into the lowermost Prince Creek Formation and the uppermost Schrader Bluff Formation. Farther offshore, the equivalent surface to the aforementioned paleovalley appears to be a subtle discontinuity between middle and lower Schrader Bluff Formation shelfal marine strata. Still farther offshore, the equivalent paleovalley surface is interpreted as a marine mass-wasting surface that locally cuts through the lowermost Schrader Bluff Formation and into the underlying Seabee Formation.

Flores, Romeo M.; Stricker, Gary D.; Decker, Paul L.; Myers, Mark D.

2007-01-01

52

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

SciTech Connect

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

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

2011-02-02

53

LOOP: first US offshore terminal will be tested in April or May  

SciTech Connect

In April or May a specially trained mooring master will board a supertanker 24 miles off Lafourche Parish Louisiana, to begin the first offloading test from a US offshore terminal. The vessel will be guided shoreward for 5 miles and positioned at one of three SALM (Single Anchor Leg Mooring) buoys. The tanker will be moored only by bowlines, permitting it to weathervane into prevaling wind and waves while it offloads into the LOOP (Louisiana Offshore Oil Port) terminal. The $630,000,000 facility is constructed in 110-ft water in Grand Isle Block 59, approximately 19 miles offshore. The terminal is the first serious US effort to build a facility capable of handling supertankers and gain the economics of scale the large-volume ships offer. The components of LOOP are discussed and the mooring systems are explained. LOOP will handle six different designations of crude imports; use of the specific caverns for segregation is important. The Clovelly facility is an underground tank farm. Crude will move in and out of the caverns via brine displacement. Crude pumped into a cavity will displace brine to the surface storage reservoir. Typically, oil leaving the Clovelly Salt Dome will head northwest through the 48 inch diameter LOCAP pipe line connecting the dome with the St. James terminal of Capline. From St. James, the crude either will be piped to refineries in Louisiana or sent up the Capline system. Because of Capline and adjacent crude pipe lines, LOOP imports are connected with approximately 25% of the nation's refinery capacity. (DP)

Not Available

1980-11-01

54

Damage-detection monitoring method for offshore platforms is field-tested  

SciTech Connect

There is a clear need to develop new methods for condition monitoring and inspection of offshore platforms. Two key reasons for this are the unreliability and the high cost of visual inspection-currently the most commonly used method. Among the inspection and monitoring methods now available, those based on vibration analysis seem to hold the greatest promise. A joint effort by two French firms has resulted in field-testing two new methods on a living quarters platform in the Arabian Gulf. This work describes the concepts, equipment, and operating procedures developed, and the significant results obtained. Full-scale experiments using vibro-detection and modal analysis, as described, have demonstrated these techniques possess considerable capability for purposes of structural integrity monitoring and potential as design aids.

Crohas, H.; Lepert, P.

1982-02-22

55

Case study of preliminary cyclic load evaluation and triaxial soil testing in offshore wind farm planning  

NASA Astrophysics Data System (ADS)

In 2020 Germany aims to produce 20% of its electrical power trough renewable energy sources. Assigned Offshore Wind farms in the German exclusive economic zone of the North- and the Baltic Sea are important step toward a fulfilment of this goal. However the save erecting of 5-6 MW wind power plants (total construction size: > 200m) in water depth of around 40 m is related to unprecedented technical, logistical and financial challenges. With an intended lifetime expectation of 50 years for the foundations, construction materials and the soils around the foundation are subject to high and continued stresses from self-weight, waves, wind and current. These stresses are not only static, but have also a significant cyclic component. An estimated 250 million cyclic load changes may lead to an accumulation of plastic deformation in the soil that potentially may affect operability or lifespan of the plant. During a preliminary geotechnical site survey of one of the largest (~150 km2) offshore wind project sites within the German Bight (~45 km North off the island Juist) a total of 16 drill cores with in situ cone penetration data and a total sample length of ~800 m where recovered. Preliminary foundation designs and static self weight and lateral load calculations were used to design a cycling triaxial lab testing program on discrete natural soil samples. Individual tests were performed by foundation type and at vertical and lateral load maxima to evaluate the long-term soil behaviour under cyclic load. Tests have been performed on granular, cohesive and intermediate natural soils. Following an introduction to the unique MARUM triaxial apparatus and testing conditions, the cyclic triaxial test results are shown and explained. Furthermore cyclic shear strength and stiffness are compared to their static counterparts. Unique soil behaviour like abrupt partial failure, pore pressure response and unexpected in part load independent cyclic deformation behaviour is discussed and compared to literature results. The shown case study is intended to demonstrate a feasible procedure for evaluating cyclic loads, designing test procedures, presenting results and interpreting data in a so far unregulated field without common standards. The presented data has been produced within the framework of germanwind, a science industry partnership including RWE-Innogy, ENOVA and MARUM.

Otto, Daniel; Ossig, Benjamin; Kreiter, Stefan; Kouery, Saed; Moerz, Tobias

2010-05-01

56

Teaching with Stratigraphic Profiles  

ERIC Educational Resources Information Center

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

Stefanich, Greg P.

1974-01-01

57

Hydrodynamic loading of slope-mounted OTEC pipelines: A review of offshore design experience and model test data requirements  

Microsoft Academic Search

Proposed slope-mounted pipelines for OTEC proof-of-concept experiments have much larger diameters than the pipelines currently being used in the offshore oil and gas industry. Test data taken from the ocean engineering literature on subsea hydrocarbon pipeline design are thus not directly applicable to these large-diameter OTEC cold water and discharge pipes. Furthermore, the proposed location of these pipes (on or

1982-01-01

58

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

USGS Publications Warehouse

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

Wrege, Beth M.; Jen, Philip S.

2004-01-01

59

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

SciTech Connect

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

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

2009-09-01

60

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

USGS Publications Warehouse

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

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

2011-01-01

61

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

USGS Publications Warehouse

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

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

2011-01-01

62

Identification of third-order (approx. 10{sup 6} yrs) and fourth-order (approx. 10{sup 5}/10{sup 4} yrs) stratigraphic cycles in the South Addition, West Cameron Lease Area, Louisiana offshore  

SciTech Connect

In the highly explored South Addition of the West Cameron Lease Area, Louisiana offshore, interpretation of a six-mile ({approx}10 km) seismic section across a single intraslope basin yielded 20 sediment packages. Several interpretive tools were necessary. Seismic stratigraphy indicated that the shallower zone was an outer shelf marked by 8 major sea level oscillations. In the portion between 1 and 3 seconds, seismic stratigraphy and paleontology led to the interpretation of depositional environments such as upper slope, and paleobathymetrically deeper intervals with descent through the section. The intraslope basin, while small, may be viewed as a micro-continental margin. Each sea level oscillation cycle apparently made a distinct progradational unit, decipherable in the seismic data. Fourth order cycles have been provisionally interpreted, throughout most of the entire 3.7 second section. Such precision is possible only in explored basins with excellent seismic data. The sequence thickness showed a seven-fold variability, from 0.08 to 0.58 seconds. The shallower section, deposited along an outer shelf, has an average individual sequence thickness of 0.13 seconds. Individual seismic sequences in the deeper section, interpreted to have been deposited on an upper slope, have average thicknesses of 0.25 seconds. The thinner sequences of the shallower section are compatible with the notion that the outer shelf was a bypass zone during a glacial epoch. The thicker sequences of the deeper section are the result of deposition onto an aggrading upper slope within an intraslope basin during a highstand.

Lowrie, A.; Meeks, P. [Specialty Office Services, Waveland, MS (United States); Hoffman, K. [Dynamics Graphics, Houston, TX (United States)

1996-09-01

63

Coupling thermo-mecanical simulation and stratigraphic modelling: impact of lithosphere deformation on stratigraphic architecture of passive margin basins.  

NASA Astrophysics Data System (ADS)

The aim of this study is to revise the view of the long-term stratigraphic trends of the Atlantic-type passive margins to include the impact of the coupling between the lithosphere deformation and the surface processes. However, modeling coupling lithosphere deformation and surface processes usually address large-scale deformation processes, i.e. they cannot resolve the stratigraphic trend of the simulated basins. On the other hand, models dedicated to stratigraphic simulation do not include these feedbacks of erosion/sedimentation on deformation processes. The recent development of a numerical modeling tool, coupling the thermal and flexural evolution of the lithosphere and including the (un)loading effects of surface processes in 3D (Flex3D; J. Braun), allows us to propose a new procedure to investigate, in 3D, the evolution of passive margins, from the scale of the lithosphere to the detailed stratigraphic architecture, including syn- and post-rift phases and onshore and offshore domains. To do this, we first simulate the syn-rift phase of lithosphere stretching by thermo-mechanical modeling (Sopal, R. Huismans). We use the resulting lithosphere geometry as input of the 3D flexural modeling to simulate the post-rift evolution of the margin. We then use the resulting accumulation and subsidence histories as input of the stratigraphic simulation (Dionisos, D. Granjeon) to model the detailed stratigraphic architecture of the basin. Using this procedure, we evaluate the signature of various boundary conditions (lithosphere geometries and thermal states, stretching distributions, surface processes efficiencies and drainage organization) in the uplift/subsidence and denudation histories as well as in the stratigraphic architectures of the associated sedimentary basins. We apply the procedure to the case study of the passive margins bounding the Southern Africa plateau, for which we have compiled data constraining the thermal history, the terrigeneous sediment accumulations, and the long term stratigraphic architectures.

Rouby, Delphine; Huismans, Ritske; Braun, Jean; Rohais, Sebastien

2013-04-01

64

Damage-detection monitoring method for offshore platforms is field-tested  

Microsoft Academic Search

There is a clear need to develop new methods for condition monitoring and inspection of offshore platforms. Two key reasons for this are the unreliability and the high cost of visual inspection-currently the most commonly used method. Among the inspection and monitoring methods now available, those based on vibration analysis seem to hold the greatest promise. A joint effort by

H. Crohas; P. Lepert

1982-01-01

65

Comparison of three marine screening tests and four Oslo and Paris Commission procedures to evaluate toxicity of offshore chemicals  

SciTech Connect

The results from the screening toxicity tests Artemia salina, Microtox{reg_sign}, and Mitochondria RET test were compared with those obtained from OSPAR (Oslo and Paris Commissions)-authorized procedures for testing of offshore chemicals (Skeletonema costatum, Acartia tonsa, Abra alba, and Corophium volutator). In this study 82 test substances (26 non-water soluble) were included. The Microtox test was found to be the most sensitive of the three screening tests. Microtox and Mitochondria RET test results showed good correlation with results from Acartia and Skeletonema testing, and it was concluded that the Microtox test was a suitable screening test as a base for assessment of further testing, especially regarding water-soluble chemicals. Sensitivity of Artemia salina to the tested chemicals was too low for it to be an appropriate bioassay organism for screening testing. A very good correlation was found between the results obtained with the Skeletonema and Acartia tests. The results indicated no need for more than one of the Skeletonema or Acartia tests if the Skeletonema median effective concentration or Acartia median lethal concentration was greater than 200 mg/L. The sediment-reworker tests (A. Alba or C. volutator) for chemicals that are likely to end up in the sediments (non-water soluble or surfactants) should be performed, independent of results from screening tests and other OSPAR species.

Weideborg, M.; Vik, E.A.; Oefjord, G.D.; Kjoennoe, O. [Aquateam-Norwegian Water Technology Centre A/S, Oslo (Norway)

1997-02-01

66

Microcomputer stratigraphic applications  

SciTech Connect

With the advent of large-capacity computer files, interactive languages for retrieval of large data bases, and low-cost effective microcomputers, the approach to stratigraphic analysis has been dramatically improved. In terms of immediate payoff, the computer assumes the role of retriever and data presenter, while the geologist concentrates on analysis of retrieved data. The biggest benefit of these new approaches is a measurable increase in productivity for the geologist. Through use of the computer, gathering and interpretive data from sample logs are greatly facilitated. With the computer, logs are encoded electronically for access by the geologist via a computer terminal, and analysis of the data is accomplished interactively. The process obviates the need for the time-consuming process of locating the appropriate logs, hanging them for analysis, and researching each log to locate appropriate intervals for correlation and interpretation. Recent studies indicate that through computerized approaches, time required for these steps is vastly diminished, and resulting productivity is 40-80% greater than with conventional manual methods. A by-product of this approach results from the data being created in a form that lends itself to graphic presentation upon demand by the geologist. This avoids the time-consuming delays inherent in interrelating with the computing department for mapping requests to ensure that the results of the analysis are as expected. With the computer, many kinds of maps become practical to produce from the terminal, including base maps, cross sections, and lithofacies, structures, and isopach maps.

Choyce, R.

1984-04-01

67

Building the Link Between NearShore Dynamics and the Stratigraphic Record  

Microsoft Academic Search

In order to further investigate the transport mechanisms and the life cycle of sediments in continental margins, an experimental approach has been designed. It is outlined by the following three objectives: monitoring near-shore dynamics using acoustic tools, measuring seabed stress and load using sensors buried in the seafloor, interpreting off-shore stratigraphic record from seismic surveys. The overall objective is to

N. Le Dantec; G. B. Deane; N. W. Driscoll

2004-01-01

68

A Small Test Model of the Transmission Grid with a Large Offshore Wind Farm for Education and Research at Technical University of Denmark  

Microsoft Academic Search

A small test model of the transmission system containing a number of central power plants, consumption centers, local wind turbines and a large offshore wind farm is implemented in the simulation tool Powerfactory (DigSilent). This small test model is used for demonstration of interaction between electricity-producing wind turbines and a realistic transmission system and investigation of problems with relation to

V. Akhmatov; A. Hejde Nielsen

2006-01-01

69

Sequence stratigraphic framework of Neogene strata in offshore Nigeria  

Microsoft Academic Search

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

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

1996-01-01

70

Stratigraphic statistical curvature analysis techniques  

SciTech Connect

SCAT applies statistical techniques to dipmeter data to identify patterns of bulk curvature, determine transverse and longitudinal structural directions, and reconstruct cross sections and contour maps. STRAT-SCAT applies the same concepts to geometric interpretation of multistoried unimodal, bimodal, or trough-type cross-bedding and also to seismic stratigraphy-scale stratigraphic structures. Structural dip, which comprises the bulk of dipmeter data, is related to beds that (statistically) were deposited with horizontal attitudes; stratigraphic dip is related to beds that were deposited with preferentially oriented nonhorizontal attitudes or to beds that assumed such attitudes because of differential compaction. Stratigraphic dip generates local zones of departure from structural dip on special SCAT plots. The RMS (root-mean-square) of apparent structural dip is greatest in the (structural) T-direction and least in the perpendicular L-direction; the RMS of stratigraphic dip (measured with respect to structural dip) is greatest in the stratigraphic T*-direction and least in the stratigraphic L*-direction. Multistoried, cross-bedding appears on T*-plots as local zones of either greater scatter or statistically significant departure of stratigraphic median dip from structural dip. In contrast, the L*-plot (except for trough-type cross-bedding) is sensitive to cross-bedding. Seismic stratigraphy-scale depositional sequences are identified on Mercator dip versus azimuth plots and polar tangent plots as secondary cylindrical-fold patterns imposed on global structural patterns. Progradational sequences generate local cycloid-type patterns on T*-plots, and compactional sequences generate local cycloid-type patterns on T*-plots, and compactional sequences generate local half-cusp patterns. Both features, however, show only structural dip on L*-plots.

Bengtson, C.A.; Ziagos, J.P.

1987-05-01

71

World offshore  

SciTech Connect

An update for offshore operations in the Bahamas, Gulf of Mexico, North Sea, Brazil, Australia, and Argentina is presented. The points of discussion are exploration targets, production figures, governmental controls, and drilling programs. There is some discussion of land leases.

Redden, J.

1984-07-20

72

Subsalt risk reduction using seismic sequence-stratigraphic analysis  

SciTech Connect

Several recent projects involving detailed seismic-sequence stratigraphic analysis of existing wells near subsalt prospects in the south additions of the offshore Louisiana area in the Gulf of Mexico have demonstrated the utility of using seismic sequence-stratigraphic analysis to reduce risk when drilling subsalt plays. First, the thick section of sediments that was thought to be above and below the salt was penetrated in the area away from the salt. These sediments were accurately dated using maximum flooding surface first occurrence downhole of important bioevent, condensed sections, abundance and diversity histograms, and high-resolution biostratigraphy while the wells were being drilled. Potential reservoir sands within specific Vail sequences in these wells were projected on seismic up to the subsalt and non-subsalt sediment interface. The systems tract above and below the maximum flooding surface and the type of reservoir sands that were to be encountered were predictable based on the paleobathymetry, increase and decrease of fauna and flora abundance, recognition of the bottom-set turbidite, slope fan and basin floor fan condensed sections, and superpositional relationship of the Vail sequences and systems tracts to provide a detailed sequence-stratigraphic analysis of the well in question. Subsequently, the wells drilled through the salt could be accurately correlated with the Vail sequences and systems tracts in wells that were previously correlated with seismic reflection profiles away from the salt layer.

Wornardt, W.W. Jr. [Micro-Strat, Inc., Houston, TX (United States)

1994-09-01

73

Eighteenth annual offshore technology conference. Volume 1  

SciTech Connect

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.

Not Available

1986-01-01

74

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

Microsoft Academic Search

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

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

1996-01-01

75

Stratigraphic Modelling of Continental Rifting  

NASA Astrophysics Data System (ADS)

Interlinks between deformation and sedimentation have long been recognised as an important factor in the evolution of continental rifts and basins development. However, determining the relative impact of tectonic and climatic forcing on the dynamics of these systems remains a major challenge. This problem in part derives from a lack of modelling tools capable of simulated high detailed surface processes within a large scale (spatially and temporally) tectonic setting. To overcome this issue an innovative framework has been designed using two existing numerical forward modelling codes: Underworld, capable of simulating 3D self-consistent tectonic and thermal lithospheric processes, and Tellus, a forward stratigraphic and geomorphic modelling framework dedicated to simulating highly detailed surface dynamics. The coupling framework enables Tellus to use Underworld outputs as internal and boundary conditions, thereby simulating the stratigraphic and geomorphic evolution of a realistic, active tectonic setting. The resulting models can provide high-resolution data on the stratigraphic record, grain-size variations, sediment provenance, fluvial hydrometric, and landscape evolution. Here we illustrate a one-way coupling method between active tectonics and surface processes in an example of 3D oblique rifting. Our coupled model enables us to visualise the distribution of sediment sources and sinks, and their evolution through time. From this we can extract and analyse at each simulation timestep the stratigraphic record anywhere within the model domain. We find that even from a generic oblique rift model, complex fluvial-deltaic and basin filling dynamics emerge. By isolating the tectonic activity from landscape dynamics with this one-way coupling, we are able to investigate the influence of changes in climate or geomorphic parameters on the sedimentary and landscape record. These impacts can be quantified in part via model post-processing to derive both instantaneous and cumulative erosion/sedimentation.

Mondy, Luke; Duclaux, Guillaume; Salles, Tristan; Thomas, Charmaine; Rey, Patrice

2013-04-01

76

Artificial lift with coiled tubing for flow testing the Monterey formation, offshore California  

SciTech Connect

This paper provides a technical comparison of jet-pump and nitrogen lift during the drillstem tests (DST's) of a low-gravity, high-viscosity crude on a semisubmersible drilling vessel. Eight DST testing sequences are presented to demonstrate that jet-pump-lift operations are better suited than nitrogen-lift techniques for obtaining reservoir data during Monterey DST's.

Peavy, M.A.; Fahel, R.A. (Oryx Energy Company (US))

1991-05-01

77

Field tests of six offshore oil containment booms. I. Final report  

Microsoft Academic Search

This report describes the test procedures and equipment used in testing six different oil containment booms in the Gulf of Mexico. Oil was not used. Each boom was evaluated for its seakeeping and logistic requirements for deployment and retrieval. Each boom was moored in a U shape, or catenary, configuration. This was done by establishing two sets of mooring buoys

P. R. Corpuz; R. A. Griffiths

1978-01-01

78

Hydrodynamic test apparatus with offshore structure model using gas bag seal at model bottoms  

SciTech Connect

An inflatable air bag for filling and sealing the gap between the flat, underside of a model of a gravity-based, exploratory drilling structure, or the like, to improve the accuracy and reliability of data obtained from hydrodynamic forces acting on the model when the latter is under test. The bag is of substantially the same shape in plan as the underside of the model and is inflated with gas to a pressure sufficient to seal the gap and prevent hydrodynamic forces from acting on the underside of the model during testing. The material of the bag is of minimal thickness so as to minimize load transfer thereto. Variations in the internal pressure of the bag during a hydrodynamic test of the model is utilized to improve the accuracy and reliability of the data obtained from load cells which support the model in the test facility.

Brogren, E. E.; Chakrabarti, S. K.

1985-12-24

79

Major marine source rocks and stratigraphic cycles  

SciTech Connect

The identification of continental encroachment cycles and subcycles by using sequence stratigraphy can assist explorationists in locating source rocks. The continental encroachment cycles are associated with the breakup of the supercontinents and fit a smooth long-term eustatic curve. They are first order, with a duration greater than 50 m.y., and are composed of transgressive and regressive phases inducing major changes in shoreline. The limit between the transgressive and regressive phases corresponds to a major downlap surface, and major marine source rocks are often found in association with this surface, particularly in the northern hemisphere. Potential {open_quotes}secondary{close_quotes} source rock intervals can also be sought by sequence stratigraphy because each continental encroachment cycle is composed of several subcycles, and the same configuration of a regressive forestepping phase overlying a transgressive backstepping phase also creates a downlap surface that may correspond with organic-rich intervals. The stratigraphic distribution of source rocks and related reserves fits reasonably well with continental encroachment cycles and subcycles. For instance, source rocks of Silurian, Upper Jurassic, and Middle-Upper Cretaceous are associated with eustatic highs and bear witness to this relationship. The recognition and mapping of such downlap surfaces is therefore a useful step to help map source rocks. The interpretation of sequence stratigraphy from regional seismic lines, properly calibrated with geochernical data whenever possible, can be of considerable help in the process. Several examples from around the world illustrate the power of the method: off-shore of eastern Venezuela, coastal basin of Angola, western Africa, the North Sea, south Algeria, and the North Caucasian trough.

Duval, B.C. [Institut Francais du Petrole, Rueil Malmaison (France)

1995-11-01

80

Modelling floating offshore units moored in broken ice: comparing simulations with ice tank tests  

Microsoft Academic Search

A numerical simulation model that simulates the behaviour of a vessel moored in broken ice has been used to compare results from numerical simulations with ice tank tests. In the simulations a tanker moored on an eight legged catenary mooring of the Submerged Turret Loading (STL) concept was towed through a broken ice field. The setup of this situation was

Edmond H Hansen; Sveinung Løset

1999-01-01

81

Evaluation of Production Tests in Oil Wells Stimulated by Massive Acid Fracturing Offshore Qatar  

Microsoft Academic Search

This paper presents the evaluation of pressure-buildup data from production tests in wells that have been stimulated by massive acid fracturing. Fracture type curves are used in combination with conventional semilog analysis techniques. Fracture characteristics are calculated from a match of the early-time pressure data with the type curves, and reservoir characteristics are calculated from a conventional semilog plot of

Simon McDonald

1983-01-01

82

Hydrodynamic test apparatus with offshore structure model using gas bag seal at model bottoms  

Microsoft Academic Search

An inflatable air bag for filling and sealing the gap between the flat, underside of a model of a gravity-based, exploratory drilling structure, or the like, to improve the accuracy and reliability of data obtained from hydrodynamic forces acting on the model when the latter is under test. The bag is of substantially the same shape in plan as the

E. E. Brogren; S. K. Chakrabarti

1985-01-01

83

Recognition of a thin stratigraphic trap by seismic reflection character analysis  

Microsoft Academic Search

The Cretaceous Cardium Formation, Alberta, Canada, which produces oil and gas from thin stratigraphic traps comprising coastal and offshore shelf sand-ridge deposits, appears as railroad tracks on seismic sections. Ninety-seven seismic lines were examined over a 10,000 km² area. Here, the Cardium is divided into the Cardium Sand and the overlying Cardium Zone, both of which are 15-50 m thick.

R. M. Slatt; K. Lighty; J. Robinson

1985-01-01

84

New concepts, environment and model testing. [Safety engineering designs for offshore platforms  

SciTech Connect

With continued low oil prices, there is a need to develop low-cost production platforms for marginal and deep water. On the other hand, there is an increasing awareness related to safety and environmental aspects. These constraints call for a high degree of innovation and integrity. The scientists and engineers working in this climate cannot accept simplification and shortcuts and it is important that proper engineering, testing and design be carried out. It is appreciated that the management of operating companies acknowledge the importance of safe design to protect lives, the environment, and their investments.

Gudmestad, O.T.

1993-02-01

85

Monitoring the Methane Hydrate Dissociation by the Offshore Methane Hydrate Production Tests using Multi-component Seismic  

NASA Astrophysics Data System (ADS)

We developed a new OBC (Ocean Bottom Cable), named as 'DSS' (Deep-sea Seismic System). The sensor has 3-component accelerometer and a hydrophone applicable for four-component (4C) seismic survey. Using the DSS, the methane hydrate dissociation zone will be tried to be monitored at the water depth of around 1000m during JOGMEC offshore methane hydrate production test in early 2013. Before the DSS, we had developed the RSCS (Real-time Seismic Cable System) with 3-component gimbaled geophones, and carried out a reflection seismic survey in the Nankai Trough in 2006. Referring this successful survey, we improved the RSCS to the DSS. The receiver size is reduced to 2/3 and the receiver case has a protective metallic exterior and the cable is protected with steel-screened armouring, allowing burial usage using ROV for sub-seabed deployment at the water depth up to 2000m. It will realize a unique survey style that leaves the system on the seabed between pre-test baseline survey and post-test repeated surveys, which might be up to 6 months. The fixed location of the receiver is very important for time-lapse monitoring survey. The DSS has totally 36 sensors and the sensor spacing is 26.5m. The total length is about 1km. We carried out the pre-test baseline survey between off Atsumi and Shima-peninsula in August, 2012.We located the DSS close to the production test well. The nearest sensor is 63m apart from the well. A newly developed real-time 3-D laying simulation system consisting of ADCP (Acoustic Doppler Current Profiler), transponders attached to the DSS, and real-time 3-D plotting system for transponder locations have been adopted. After we laid the cable, we buried the DSS using ROV (Remotely Operated Vehicle). The baseline survey included 2D/3D seismic surveys with shooting vessel and cable laying/observation ship. The resultant 2D section and 3D volume shows the good quality to delineate the methane hydrate concentrated zone. After the baseline survey, we have left the DSS on seafloor until the first monitoring survey scheduled in April 2013, because the fixed location of the sensors is essential for time-lapse monitoring survey.

Asakawa, Eiichi; Hayashi, Tsutomu; Tsukahara, Hitoshi; Takahashi, Hiroo; Saeki, Tatsuo

2013-04-01

86

Ice interaction with offshore structures  

SciTech Connect

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.

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

1988-01-01

87

Smarter offshoring.  

PubMed

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. PMID:16770896

Farrell, Diana

2006-06-01

88

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

SciTech Connect

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

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

2010-03-01

89

Subsidence and stratigraphic modeling of the US Atlantic margin  

SciTech Connect

The deep offshore basins of the US Atlantic margin show an exponential subsidence consistent with lithospheric extension followed by cooling. In the Baltimore Canyon Trough, extension reaches ..beta.. approx. =4. The resultant deep burial and inaccessibility of the syn-rift sediment preclude a detailed understanding of the rifting history. On the other hand, the general similarity of predicted subsidence for all rifting models during the later post-rift period allows a detailed reconstruction of the paleobathymetry and an evaluation of the nature of the control of the stratigraphic record. Layer by layer backstripping indicates that there has been no major erosional retreat of the Early Cretaceous shelf edge. The change in position of the shelf edge following the termination of the Jurassic-Early Cretaceous reef, was accomplished by a gentle sagging and sediment supply variations. Stratigraphic modeling reveals the primary factors affecting the post-rift development of the shelf. These are the presence of a broad thermal uplift during the Jurassic at the site of the present coastal plain, increasing flexural rigidity of the lithosphere creating the coastal plain wedge, and a moderate (150-200 m) sea level fall since the Late Cretaceous in order to match the observed thicknesses and coastal onlap-offlap patterns during the Cenozoic.

Steckler, M.S.; Watts, A.B.; Thorne, J.A.

1985-01-01

90

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

Microsoft Academic Search

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

D. Abrahao; J. E. Warme

1988-01-01

91

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

SciTech Connect

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.

Richardson, S.M.; Bott, W.F.; Birse, T.C.R. [British Gas Exploration & Production Ltd., Reading (United Kingdom)

1995-08-01

92

Proceedings of the nineteenth annual offshore technology conference. Vol. 2  

SciTech Connect

This book presents the papers given at a conference on offshore platforms. Topics considered at the conference included ice forces, multi-leg structures, subsea completions, computer graphics, algorithms, positioning, tanker ships, wave forces, moorings, stability, leaks in submarine pipelines, damping, offshore drilling, nonlinear dynamic analysis of hybrid riser systems, fatigue life analysis, offshore microprocessors, materials testing, corrosion, and terminal facilities.

Not Available

1987-01-01

93

Neogene sequence stratigraphy, Nam Con Son Basin, offshore Vietnam  

Microsoft Academic Search

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

K. J. McMillen; E. K. Lee; S. S. Hong

1996-01-01

94

Pacific offshore record of plinian arc volcanism in Central America: 1. Along-arc correlations  

Microsoft Academic Search

We collected 56 marine gravity cores from the Pacific seafloor offshore Central America which contain a total of 213 volcanic ash beds. Ash-layer correlations between cores and with their parental tephras on land use stratigraphic, lithologic, and compositional criteria. In particular, we make use of our newly built database of bulk-rock, mineral, and glass major and trace element compositions of

S. Kutterolf; A. Freundt; W. Peréz; T. Mörz; U. Schacht; H. Wehrmann; H.-U. Schmincke

2008-01-01

95

Pliocene paleoenvironment evolution as interpreted from 3D-seismic data in the southern North Sea, Dutch offshore sector  

Microsoft Academic Search

A high-resolution 3D-seismic survey from the Dutch offshore sector has been interpreted and subsequently correlated with existing regional seismo-stratigraphic concepts derived from conventional 2D-seismic data sets. The interpreted 13 seismic units have been related to a newly established chrono-stratigraphic framework [Kuhlmann et al., 2006a,b. Chronostratigraphy of Late Neogene sediments in the southern North Sea Basin and paleoenvironmental interpretations. Palaeogeography, Palaeoclimatology,

Gesa Kuhlmann; Theo E. Wong

2008-01-01

96

Stratigraphic control of flow and transport characteristics.  

PubMed

Ground water flow and travel time are dependent on stratigraphic architecture, which is governed by competing processes that control the spatial and temporal distribution of accommodation and sediment supply. Accommodation is the amount of space in which sediment may accumulate as defined by the difference between the energy gradient and the topographic surface. The temporal and spatial distribution of accommodation is affected by processes that change the distribution of energy (e.g., sea level or subsidence). Fluvial stratigraphic units, generated by FLUVSIM (a stratigraphic simulator based on accommodation and sediment supply), with varying magnitudes and causes of accommodation, were incorporated into a hydraulic regime using MODFLOW (a ground water flow simulator), and particles were tracked using MODPATH (a particle-tracking algorithm). These experiments illustrate that the dominant type of accommodation process influences the degree of continuity of stratigraphic units and thus affects ground water flow and transport. When the hydraulic gradient is parallel to the axis of the fluvial system in the depositional environment, shorter travel times occur in low-total accommodation environments and longer travel times in high-total accommodation environments. Given the same total accommodation, travel times are longer when sea-level change is the dominant process than those in systems dominated by subsidence. PMID:17257334

Edington, Dwaine; Poeter, Eileen

97

Stratigraphic control of flow and transport characteristics.  

PubMed

Ground water flow and travel time are dependent on stratigraphic architecture, which is governed by competing processes that control the spatial and temporal distribution of accommodation and sediment supply. Accommodation is the amount of space in which sediment may accumulate as defined by the difference between the energy gradient and the topographic surface. The temporal and spatial distribution of accommodation is affected by processes that change the distribution of energy (e.g., sea level or subsidence). Fluvial stratigraphic units, generated by FLUVSIM (a stratigraphic simulator based on accommodation and sediment supply), with varying magnitudes and causes of accommodation, were incorporated into a hydraulic regime using MODFLOW (a ground water flow simulator), and particles were tracked using MODPATH (a particle-tracking algorithm). These experiments illustrate that the dominant type of accommodation process influences the degree of continuity of stratigraphic units and thus affects ground water flow and transport. When the hydraulic gradient is parallel to the axis of the fluvial system in the depositional environment, shorter travel times occur in low-total accommodation environments and longer travel times in high-total accommodation environments. Given the same total accommodation, travel times are longer when sea-level change is the dominant process than those in systems dominated by subsidence. PMID:17087754

Edington, Dwaine; Poeter, Eileen

98

Stratigraphic Evidence of Sorted Bedform Evolution  

Microsoft Academic Search

An examination of inner shelf sediments off Tairua on the north east coast of New Zealand provides stratigraphic evidence of the manner in which `sorted bedforms' or `rippled scour depressions' evolve and the oceanographic or geological conditions control their growth. Side-scan sonar, seismics and 15 vibracores (6 m long), interpreted in the context of wider field studies including swath mapping,

T. M. Hume; G. Coco; M. O. Green; B. Murray; A. Trembanis; J. McNinch

2005-01-01

99

Offshore Essaouira basin: Geology and hydrocarbon potential  

SciTech Connect

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.

Jabour, H.; Ait Salem, A. (ONAREP, Rabat (Morocco))

1991-03-01

100

Offshore yearbook, 1987  

SciTech Connect

This book is an annual compilation of information and articles on offshore petroleum operations. It includes an industry analysis, engineering highlights, a news review of the Western Hemisphere, and an industry outlook for 1987. It provides survey information on deepwater wells, worldwide offshore daily oil production, producing fields by country, and international offshore well count. It also contains mobile rig statistics, including rig scrappings, rig name changes, cold-stacked and for-sale units, and unit types.

Not Available

1987-01-01

101

Subsurface sequence stratigraphic correlation using well logs  

NSDL National Science Digital Library

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

Gani, M. R.

102

Offshore wind energy prospects  

Microsoft Academic Search

In last two years offshore wind energy is becoming a focal point of national and non national organizations particularly after the limitations of fossil fuel consumption, adopted by many developed countries after Kyoto conference at the end of 1997 on global climate change. North Europe is particularly interested in offshore for the limited land areas still available, due to the

Gaetano Gaudiosi

1999-01-01

103

Session: Offshore wind  

Microsoft Academic Search

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

Jette Gaarde; Bonnie Ram

2004-01-01

104

Offshore oil: an overview  

SciTech Connect

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

Manners, I.R.

1980-06-01

105

Pricing offshore wind power  

Microsoft Academic Search

Offshore wind offers a very large clean power resource, but electricity from the first US offshore wind contracts is costlier than current regional wholesale electricity prices. To better understand the factors that drive these costs, we develop a pro-forma cash flow model to calculate two results: the levelized cost of energy, and the breakeven price required for financial viability. We

Andrew C. Levitt; Willett Kempton; Aaron P. Smith; Walt Musial; Jeremy Firestone

2011-01-01

106

A mid-Cretaceous prograding sedimentary complex in the Sisimiut Basin, offshore West Greenland—stratigraphy and hydrocarbon potential  

Microsoft Academic Search

A prograding and aggrading depositional system has been mapped from seismic data in the Sisimiut Basin, offshore West Greenland. Seismic stratigraphic analysis resulted in mapping of three seismic sequences and internal boundaries. Mounds at the base of the prograding sequences may represent massflows, which could be prospective. The sealing deposits are Cretaceous claystone, indicated by correlation to the Ikermiut-1 well.

Ulrik Gregersen; Nina Skaarup

2007-01-01

107

Proceedings of the seventh international conference on offshore mechanics and Arctic engineering  

SciTech Connect

These proceedings collect papers given at a conference on offshore engineering. Topics include: fracture mechanics, vibration testing, wave energy converters, ocean thermal energy converters, underwater pipelines, offshore platforms, and design and installation of permanent mooring systems for tankers.

Chung, J.S.; Sparks, C.P.; Brekke, J.N.; Clukey, E.C.; Penney, T.R.

1988-01-01

108

Depositional history and tectonic evolution of Late Triassic Age rifts of the United States central Atlantic margin: Results of an integrated stratigraphic, structural, and paleomagnetic analysis of the Taylorsville and Richmond Basins  

NASA Astrophysics Data System (ADS)

Subsurface, onshore and offshore rifts, found throughout the U.S. mid-Atlantic margin, are known from geophysical imaging and few test wells. My analysis of the largely subsurface Taylorsville rift is based on over 13 km of continuous rock core and well cuttings, more than 250 kin of seismic reflection profiles, outcrop studies, and laboratory paleomagnetic experiments. This study is the most complete evaluation of one of the subsurface rifts in eastern North America. The Taylorsville Basin is Late Triassic, Carnian to Norian in age and contains more than 4.5 km of stratigraphic section in two, unconformity-bounded tectonostratigraphic sequences. The lower sequence was deposited in sub-regional scale half-grabens formed during the initial stages of rifting. The upper sequence was deposited in a regional-scale half-graben formed by the linkage of several sub-regional rift normal faults. An erosional unconformity formed in the lower sequence rocks during the transition from sub-regional to regional-scale rifting. Post-rift deformation included reverse faulting, compressional folding, and dike emplacement from tectonic inversion during the latest Triassic and earliest Jurassic. The neighboring Richmond rift experienced a similar stratigraphic and structural history, but subsidence of the Richmond Basin ended in the Carnian while the Taylorsville Basin continued subsiding into the Norian. The paleomagnetic analysis of Taylorsville cores reveal normal and reverse polarity Late Triassic age magnetization. The 11 paleomagnetic reversal zones of the Taylorsville Basin magnetostratigraphic section correlate one-to-one with zones E6r through E17n of the Late Triassic Newark Basin reference section. The Taylorsville Basin spans more than 23 m.y. from about 234 Ma to 211 Ma. The large-scale stratigraphic patterns observed in the Taylorsville and Richmond basins conform well to predictions of tectonically controlled basin filling models. The small scale variability in the large-scale patterns reveal the influence of paleolatitude and orbital climatic change on rift sedimentation.

Letourneau, Peter Mark

109

IT Offshoring and American Labor  

Microsoft Academic Search

This article presents an overview of the offshoring of information technology (IT), especially software and IT-enabled services, and its impacts on American labor. Topics include the history of offshoring politics in the United States, differences in attitudes between politicians and economists in their attitudes about the severity of the offshoring “problem,” national differences in types of offshoring providers, technological and

William Aspray

2010-01-01

110

Seismic stratigraphy of the offshore Nile delta  

SciTech Connect

The seismic stratigraphy of the offshore Nile delta has been established using a 10,000-km Merlin reprocessed regional seismic database. This paper focuses on the Neogene interval in which three major seismic super sequences have been recognized. The oldest (super sequence A) is a thick sheet unit of middle Miocene age composed of marine shales and sandstones, affected in places by shale diapirism. The upper super sequence, of Pliocene age (C), is characterized by progradation complicated by both slumping and faulting. These sediments represent deposits from the present Nile delta system, a relatively recent event. Between super sequences A and C lies a thin upper Miocene - lowermost Pliocene unit (super sequence B). This unit can be divided into three sequences, the upper and lower of which (Abu Madi and Oawasim Formations, respectively) are characterized by widespread channeling. The intermediate Messinian sequence, commonly evaporitic, may also be associated with channeling episodes. Potential hydrocarbon plays exist in all three super sequences, and varied trapping mechanisms may be invoked. Dip closures are associated with both rollover on listric normal faults and shale diapirism. Stratigraphic trap potential involves both truncation of C beneath B, occasionally associated with severe angular unconformity, and super sequence B channeling. The Abu Madi channel-fill sand bodies form the primary exploration target. Despite only 12 offshore wells drilled, there have already been gas discoveries (Abu Qir field, Naf-1 well) which, together with recent changes in Egyptian hydrocarbon legislation, make this region an attractive exploration province.

Kilenyi, T.; Trayner, P.; Doherty, M.; Jamieson, G.

1988-08-01

111

Offshore Pipeline Failures.  

National Technical Information Service (NTIS)

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 10...

R. D. Woodson

1990-01-01

112

CONFERENCE REPORT: Engineering offshore  

Microsoft Academic Search

Report on 3rd international offshore mechanics and arctic engineering symposium (part of Energy sources technology conference and exhibition), ASME and others, 12-16 February 1984 in New Orleans, USA.

Tony Blakeborough

1984-01-01

113

Session: Offshore wind  

SciTech Connect

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

Gaarde, Jette; Ram, Bonnie

2004-09-01

114

Paleontological Events: Stratigraphic, Ecologic, and Evolutionary Implications  

NASA Astrophysics Data System (ADS)

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

Bralower, Timothy J.

115

Stratigraphic Assessment of the Mineral Aggregate Resources in the St. Bernard Shoals, Offshore Louisiana.  

National Technical Information Service (NTIS)

This report describes the results of an assessment of sand resources of the St. Bernard Shoals, and it examines the Holocene geologic framework of the St. Bernard Shoals region on the Louisiana-Mississippi continental shelf. These shoals are located about...

D. Pope P. Connor S. Penland

1993-01-01

116

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

SciTech Connect

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

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

1996-05-01

117

“Slicing the Value Chain” Internationally: Empirical Evidence on the Offshoring Strategy by French Firms  

Microsoft Academic Search

This paper analyzes the offshoring strategy from an empirical view. It focuses on a set of models, extracts a set of testable hypothesises and creates a suitable set of variable to test their validity. This analysis is based on a data set from French manufacturing firms that provides detailed information on the offshoring strategy. The choice of offshoring modes is

Liza Jabbour

118

FBG sensors for the measurement of the dynamic response of offshore oil platform model  

Microsoft Academic Search

The dynamic response of offshore oil platform under seismic excitation is the coupling response of liquid and solid vibration. In recent years, the computation of dynamic responses and design of offshore platform have attracted the attention of many researchers. This paper presents a shaking table test of offshore oil platform model scaled down an actual one. Fiber Bragg grating is

Li Sun; Hongnan Li; Qiao Jin

2005-01-01

119

Oil and gas exploration, offshore southern California  

SciTech Connect

Four local Tertiary basins comprise the regional Pacific Basin south of Point Conception: the San Diego trough and the offshore Los Angeles, Outer Banks, and Ventura-Santa Barbara Channel Basins. The San Diego trough has not been tested by deep wells. The offshore Los Angeles Basin produces oil and gas from Neogene sandstones in giant oil fields which extend on shore. The Outer Banks Basin is primarily a late cretaceous and Eocene-Oligocene basin which does not extend on shore; 6 test wells have been drilled since the 1975 sale, but no discoveries have been announced. The offshore Ventura-Santa Barbara Channel Basin produces oil and gas from Pliocene, Miocene, Oligocene, and Eocene sandstones and from fractured Monterey chert and siliceous shale of Miocene age; major future reserves are expected to be found in these reservoirs. 13 references.

Wallis, W.S.

1981-01-01

120

Stratigraphic and structural interpretation with 3-D seismic coherence  

Microsoft Academic Search

3-D seismic discontinuity is useful for identifying faults, stratigraphic features and the relationship between them. This paper covers the application of coherence technology to three basins; the Gulf of Mexico, the North Sea, and the Ardmore Basin of Oklahoma. In the Gulf of Mexico, 3-D coherence data may be used to simultaneously view faults and stratigraphic features and therefore see

M. Bahorich; J. Lopez; N. Haskell; S. Nissen; A. Poole

1996-01-01

121

APPLICATION OF TRANSITION PROBABILITY GEOSTATISTICS IN A DETAILED STRATIGRAPHIC FRAMEWORK  

Microsoft Academic Search

Heterogeneity of hydraulic properties at multiple scales in an alluvial aquifer is largely controlled by the distribution of facies. Therefore, we require quantified stratigraphic and sedimentologic models in order to incorporate this spatial variability of hydraulic properties into groundwater flow and contaminant transport simulations. Our approach uses sequence stratigraphic concepts, developed for the fluvial fan continental setting to (1) delineate

Gary S. Weissmann

122

Forward stratigraphic modeling of the Permian of the Delaware Basin  

Microsoft Academic Search

Permian platform-to-basin strata of the Delaware Basin In west Texas and New Mexico represent one of the world's most complete, best studied, and most hydrocarbon productive records of this geologic period in the world. This superb marriage of a refined stratigraphic framework and active exploration provided impetus to develop a forward stratigraphic model of this section to better predict the

Ye Qiucheng; C. Kerans; S. Bowman

1996-01-01

123

Evolving sequence-stratigraphic concepts: Emphasis on siliciclastic systems tracts  

Microsoft Academic Search

During the past five years, rapidly evolving new sequence-stratigraphic concepts have begun to impose significant changes in the application of stratigraphy in petroleum exploration and reservoir development. The growing number and variety of oral and published papers on sequence stratigraphy clearly document this stratigraphic revolution. Not since depositional systems concepts evolved in the 1960s to give rise to seismic stratigraphy

L. F. Jr

1994-01-01

124

Getting offshoring right.  

PubMed

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 to get that quality. PMID:16334588

Aron, Ravi; Singh, Jitendra V

2005-12-01

125

Climate cyclicity revealed from X-ray CT images of deep offshore sediments  

Microsoft Academic Search

We present a methodology to assess climate variability by using X-ray computed tomography (CT) images along with laboratory velocity measurements and borehole logs and apply it to a specific stratigraphic interval in deep water Campos Basin, offshore Brazil. The higher resolution of sampling in the core data (extracted from 2.8km depth) overcomes the aliasing and smoothing effect of log-based measurements

M. Grochau; T. M. Muller; E. Campos; B. Clennell; B. Gurevich

2009-01-01

126

Reservoir characterization of the Miocene Starfak and Tiger Shoal fields, offshore Louisiana through integration of sequence stratigraphy, 3-D seismic, and well-log data  

NASA Astrophysics Data System (ADS)

Many "mature" Gulf of Mexico (GOM) fields, due to their structurally and stratigraphically complex nature, possess significant remaining resources. Such is the case in the Starfak and Tiger Shoal fields, offshore Louisiana. In these fields, forty hydrocarbon reservoirs occur in a regressive Miocene-age succession that comprises 10 third-order and at least 58 fourth-order sequences. Reservoir-scale heterogeneity is controlled by the nature and distribution of sedimentary facies and is usually below the resolution of current subsurface seismic sampling. Sequence-stratigraphic analysis helps to improve predictions of spatial and temporal reservoir heterogeneity. This study addresses the application of the correlation between petrophysical properties (PP) (e.g., effective porosity and shale volume) and seismic attributes (SA) within a high-frequency sequence-stratigraphic framework to identify untapped reservoir compartments in the two offshore Louisiana fields. Synthetic modeling of the seismic data showed that the vertical resolution of the seismic is approximately 12 ms. The relief on the fourth-order sequence boundary (SB) is below seismic resolution. A new method of mapping fourth-order SBs was developed. This method is based on the ability to image planiform morphology along the SB that can be depicted from a sequence of 4-ms-thick stratal slices. This method was successfully applied in the study area, and showed increased resolution when compared to two other mapping methods (manual tracking and proportional slicing). Three methods were tested to correlate SA with PP: (1) direct correlation between SAs and PPs through regression analysis, (2) seismic inversion, and (3) probabilistic neural network (PNN). Among the three methods, the PNN proved to be the best technique. Four uncontacted compartments targeting incised-valley sands in genetic sequence 30 were identified upon analyzing the inverted Vshale volume created using PNN method. Starfak and Tiger Shoal are typical of mature shelf-bound fields in the GOM, with long and sustained production histories. Structural and stratigraphic heterogeneities present opportunities for reserve-growth potential if an improved process for mapping of geologic complexity can be unraveled.

Badescu, Adrian Constantin

127

Tectonic and stratigraphic evolution in South Alboran Sea (Morocco)  

NASA Astrophysics Data System (ADS)

The Alboran Basin, in western Mediterranean, concentrates on a relatively small surface and densely-populated, a large structural complexity linked to seismic activity with recurrent mass-transport deposits that may trigger tsunamis. It was formed by Oligo-Miocene extension while tectonic inversion occurred since the Late Miocene (Tortonian) due to the African-European collision. This North-South compression produces a conjugated fault system located in the central area from Al Hoceima to Andalusia. Numerous instabilities are linked to the recent and present-day seismic activity and show the link between seismicity and erosion-sedimentation processes. On the Andalusia margin the active structures have been identified and recently mapped in detail by using MBES data (including backscatter), and high-resolution seismic data. Such detailed studies have not yet been carried out on the Moroccan margin. The Marlboro-1 oceanographic cruise (R/V Côtes de la Manche, July 2011) has imaged and constrained active structures and associated sedimentary systems through seismic reflection data (MCS). The Xauen/Tofino banks (growth folds), the Alboran Ridge, and the Al Hoceima basin offshore Morocco have been selected because they constitute key-study areas that record a complete deformation history since the Tortonian. Active features including faults, growth folds, channels, mass transport deposits, contourites and volcanoes has provided first order tectonic and sedimentary markers of the basin's evolution. A high chrono-stratigraphical resolution will constitute the basis for reconstructing the evolution of this tectonically active area marked by strong seismic activity. The Marlboro-1 cruise will allow determining key-study area of the Marlboro-2 cruise scheduled for 2012 (R/V Téthys-II, CNFC Call). These cruises should allow for the acquisition of data necessary to characterize basin morphology, active tectonic and sedimentary structures and also make the link with existing 2D seismic lines that image deeper structures. The Marlboro proposals are linked to the international MerAlbo and SARAS cruises (Ifremer-IPEV-IRD and Eurofleets proposals), the French Termex CNRS Program, Actions Marges research group, and the Spanish and European programs Contouriber and Topomed. The aim of these cruises is to acquire a full geophysical and geological dataset to allow increase our knowledge and understanding of the tectonic and sedimentary processes acting at different spatial and temporal scales that are responsible for creating potentially catastrophic events such as earthquakes, slope failures and consequently tsunamis.

D'Acremont, E.; Gorini, C.; El Abbassi, M.; Farran, M.; Leroy, S.; Mercier De Lepinay, B. F.; Migeon, S.; Poort, J.; Ammar, A.; Smit, J.; Ercilla, G.; Alonso, B.; Scientific Team of the Marlboro project

2011-12-01

128

Alaskan North Slope stratigraphic nomenclature and data summary for government-drilled wells  

SciTech Connect

In the years since the discovery of the Prudhoe Bay oil field in 1968, a great amount of new information on the geology of the North Slope has become available, largely as a result of continued oil exploration and development. In an attempt to organize and summarize some of this information, the author has compiled in this chapter an annotated list of North Slope Stratigraphic names and a tabulation of selected well data for Government-drilled North Slope wells. This work was facilitated by the National Petroleum Reserve in Alaska (NPRA) computerized data base. The list of stratigraphic names includes names for most of the rock units that might be encountered in wells or surface exposures anywhere on the North Slope. Because these names are accompanied by explanatory notes or references, this chapter provides the first update of North Slope stratigraphic nomenclature since the earlier summary by Kopf. The tabulation of well data is patterned after the summary made by Collins and Robinson of wells drilled during the Pet-4 Program. This summary includes updated information on each of the 81 Pet-4 wells and information on all of the 45 wells drilled by the Government since then. For each well, the information provided consists of identification, location, hydrocarbon occurrences, and drilling period; total depth and depths of penetration of stratigraphic units; cores attempted and core recovery; and drillstem or production test results.

Bird, K.J.

1989-01-01

129

Marine Pollution from Offshore Chemicals.  

National Technical Information Service (NTIS)

The report analyses the influencing impact on the marine environment caused by the various chemical effluents from the offshore drilling and production. The offshore chemicals used at the Statfjord and Ekofisk fields on the Norwegian Continental Shelf are...

O. Bjoerseth G. Halmoe R. Romslo T. Syvertsen

1986-01-01

130

Energy from Offshore Wind: Preprint  

SciTech Connect

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

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

2006-02-01

131

Offshore and Arctic operations, 1991  

Microsoft Academic Search

This book contains the following topics: Design advantages of Beta Titanium 38-644 springs in outfield applications, Caissin support structure (CSS), Optimizing operations for offshore platform fabrication, Concrete strength evaluation of offshore structures.

R. G. Urquhart; A. S. Tawfik

1991-01-01

132

Improved Offshore Recovery. Pt. 5.  

National Technical Information Service (NTIS)

This section of the proceedings contains five papers covering: Improving recoveries from offshore chalk reservoirs; Improved recovery from thin oil sands, Part I Frigg field; Part II Troll field; Part III Balder field; Improved offshore recovery-state of ...

1984-01-01

133

Drilling and producing offshore  

SciTech Connect

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

Hall, R.S.

1983-01-01

134

California offshore LNG port feasible  

Microsoft Academic Search

An offshore facility for liquefied natural gas (LNG) has been declared technologically and economically feasible by the California Coastal Commission, which is also charged with selecting the best onshore site. The Commission chose an offshore site in Ventura County on the basis of its remoteness and fewer potential environmental impacts. An offshore LNG terminal is estimated to cost in the

Murnane

1978-01-01

135

Offshore platform cathodic protection retrofits  

SciTech Connect

Cathodic protection (CP) is the primary technique used for underwater corrosion control on the majority of offshore steel structures. Offshore platforms are often kept in service far beyond their original design life. Refurbishment of the CP system is required when adequate protection can no longer be maintained. Various offshore platform CP retrofit designs are discussed.

Turnipseed, S.P. [Chevron Research and Technology Co., Richmond, CA (United States)

1996-10-01

136

New stratigraphic technologies in exploration/exploitation  

SciTech Connect

With the demand for increased accuracy and precision in the interpretation of seismic sections for the prediction of reservoirs and traps, traditional paleontologic and new non-paleontologic stratigraphic data have assumed a greater role in exploration/exploitation. Strata bounded by sequence boundaries can be dated have assumed a greater role in exploration/exploitation. Strata bounded by sequence boundaries can be dated precisely by the graphic correlation technique. For example, Arabian Cretaceous reservoirs pinch out by facies change and diagenesis into coeval strata. But Pliocene sands in the Gulf Coast are truncated by regional unconformities accentuated by salt dome movement. In this Plio-Pleistocene section high precision chronostratigraphy is achieved by the integration of paleontological and geochemical data. Detailed biostratigraphic analysis of many sections of Mississippian carbonates along the eastern side of the Transcontinental Arch allows for the recognition of four unconformity-bounded units (biothems of Lane and others, 1994). These biotherms have been traced form Illinois to New Mexico and are not easily detected in the subsurface by using seismic or electric log technology because of the rather uniform carbonate lithologies composing the entire Mississippian in the region. Mississippian hydrocarbon production in western Kansas can be shown to be associated with these intra-Mississippian carbonate-on-carbonate unconformities that are easily detected biostratigraphically.

Scott, R.W. [Precision Stratigraphy Associates, Tulsa, OK (United States); Lane, H.R. [Amoco, Houston, TX (United States)

1995-09-01

137

Stratigraphic evolution of paleozoic erathem, northern Florida  

SciTech Connect

Unmetamorphosed Paleozoic sedimentary and volcanic rocks have been drilled in numerous wells throughout northern Florida and southern Georgia, in what is today a gently folded and block-faulted relict continental fragment of northwest Africa and northeast South America. Stratigraphic and lithologic equivalents of these North American Paleozoic units are prolific hydrocarbon producers in North Africa. The northern Florida Paleozoic sediments were deposited on Pan-African and Cadoman basement. Widespread continental glaciation from late Precambrian to Early Cambrian introduced a thick sequence of fine-grained marine sandstones (glacial flour), which overlie medium to coarse-grained glaciofluvial sandstones. Basinward of the sand shelf, the accretion of a volcanic island arc complex began during the Ordovician. A fluctuating transgression, accompanying a major glacial minimum, brought open-marine, graptolitic, black shales onto the sand shelf, producing an interbedded shoreface-shelf sand and black shale section during the Middle and Late Ordovician. At the Ordovician-Silurian boundary, renewed continental glaciation lowered sea level, producing a widespread unconformity. A Late Silurian major marine transgression returned black, graptolitic, highly organic shales onto the sand shelf. Devonian deltaic sands from Avalonia(.) to the north and the craton to the south closed the Paleozoic sedimentary record of northern Florida.

Coleman, J.L. Jr.

1985-02-01

138

Stratigraphic and structural interpretation of Willapa basin  

SciTech Connect

Willapa basin is a middle Eocene to Holocene depocenter in southwestern Washington and on the adjacent continental shelf. Surface geology, biostratigraphy, and seismic and well data have been used to develop a stratigraphic and structural interpretation of the basin. Middle Eocene deep-water sediments were deposited on convergent margin and accreted to North America prior to the early Miocene. Turbidite sandstones interpreted to be the lower to middle Miocene Astoria(.) Formation overlie this Eocene sequence in onshore wells. Distal turbidites of lower to middle Miocene age (Hoh assemblage) were thrust beneath the Eocene and Astoria(.) Formation rocks during the middle to upper Miocene. Upper Miocene bathyal shales and siltstones unconformably overlie the older rocks. This sequence was then unconformiably(.) covered by upper Miocene sandstones and siltstones deposited in a nearshore shelf environment. This extreme change in water depth is interpreted to be of tectonic origin. The occurrence of redeposited lower to middle Miocene deep-water fauna in the late Miocene shelf sequence is ascribed to erosion at the sea floor of mud diapirs rooted in Hoh assemblage rocks. Activation of these diapirs was probably associated with this tectonic uplift. Pliocene and Pleistocene conglomerates, sandstones, and siltstones were deposited in both marine and deltaic environments and are locally exhibited as an onlap sequence in marine seismic data. Diapiric growth has continued into the Holocene, resulting in both angular truncation of the Pliocene-Pleistocene sequence and diapiric breaching at the sea floor.

Palmer, S.P.

1989-04-01

139

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

SciTech Connect

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

Not Available

1987-12-18

140

Industry tackles offshore decommissioning  

Microsoft Academic Search

A number of issues still remain unresolved concerning the oil and gas industry`s plans for decommissioning offshore production equipment, especially in deeper waters. Some options preferred by the industry are: deepwater disposal; creation of artificial reefs; and partial removal to more than 85 ft of water depth and leaving the remaining structure in place. The complicating factor for these scenarios

Moritis

1997-01-01

141

Offshore world petroleum frontiers  

Microsoft Academic Search

The potential to find the large oil and gas fields of the future lies in the offshore frontiers. Exploration for petroleum in the coming decades must be concentrated on discovering commercial supplies of the hydrocarbons that lie untapped in these areas. New and better uses of geology, geophysics, petroleum engineering, and technology must be employed in all aspects of exploration,

Halbouty

1983-01-01

142

Offshore balancing revisited  

Microsoft Academic Search

The “Through the Looking Glass” contributors reveal that U.S. hegemony is a double?edged sword. As the debate about future U.S. grand strategy unfolds after September 11, offshore balancing should become the successor strategy to primacy.

Christopher Layne

2002-01-01

143

Pyramidal offshore structure  

SciTech Connect

Tethered or bottom-ballasted offshore platforms preferably have a pyramidal configuration. Struts connect the apexes of a polyhedron configuration to form a triangle defining each face. The pyramidal configuration can be ballasted to the bottom in relatively shallow water. A hexahedron configuration can be tethered in deep water with tension members and flotation members.

Grimsley, R.L.; Gawel, L.J.

1984-03-20

144

Combination offshore drilling rig  

Microsoft Academic Search

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

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

1986-01-01

145

Stratigraphic sequence analysis of the Antler foreland  

SciTech Connect

Mid-Upper Devonian to Upper Mississippian strata in western Utah were deposited in the distal Antler foreland. They record lateral and vertical changes in depositional environments that define five successive stratigraphic sequences, each representing a third-order transgressive-regressive cycle. In ascending order, these sequences are informally named the Langenheim (LA) of late Frasnian to mid-Famennian age, the Gutschick (GU) of late Famennian to early Kinderhookian age, the Morris (MO) of late Kinderhookian age; the Sadlick (SA) of Osagean to early Meramecian age, and the Maughan (MA) of mid-Meramecian to Chesterian age. MO is widespread and recognized within carbonate rocks of the Fitchville Formation and Joana Limestone. SA formed in concert with and to the east and south of the Wendover foreland high; the Delle phosphatic event marks maximum marine flooding during SA deposition. The transgressive systems tract of MA includes rhythmic-bedded limestone in the upper part of the Deseret Limestone in west-central Utah and, farther west, the hypoxic limestone and black shale of the Skunk Spring Limestone Bed and part of the overlying Chainman Shale. Traced westward into Nevada, MA first oversteps SA and then MO. Lithostratigraphic correlation of these sequences still farther west into the Eureka thrust belt (ETB) could mean that the youngest strata truncated by the Roberts Mountains thrust belong to the MA and that this thrust is simply part of the post-Mississippian ETB. However, some strata in central Nevada that lithically resemble those of the MA are paleontologically dated as Early Mississippian, the age of sequences overstepped by MA not far to the east. Thus, at least some imbricates of the ETB may contain a sequence stratigraphy which reflects local tectonic control.

Silberling, N.J.; Nichols, K.M.; Macke, D.L. (Geological Survey, Denver, CO (United States))

1993-04-01

146

The stratigraphic filter and bias in measurement of geologic rates  

NASA Astrophysics Data System (ADS)

Erosion and deposition rates estimated from the stratigraphic record frequently exhibit a power-law dependence on measurement interval. This dependence can result from a power-law distribution of stratigraphic hiatuses. By representing the stratigraphic filter as a stochastic process called a reverse ascending ladder, we describe a likely origin of power-law hiatuses, and thus, rate scaling. While power-law hiatuses in certain environments can be a direct result of power-law periods of stasis (no deposition or erosion), they are more generally the result of randomness in surface fluctuations irrespective of mean subsidence or uplift. Autocorrelation in fluctuations can make hiatuses more or less heavy-tailed, but still exhibit power-law characteristics. In addition we show that by passing stratigraphic data backward through the filter, certain statistics of surface kinematics from their formative environments can be inferred.

Schumer, Rina; Jerolmack, Douglas; McElroy, Brandon

2011-06-01

147

Offshore space center (offshore launch site)  

SciTech Connect

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.

Harvey, D.G.

1980-07-01

148

SINTEF focuses on offshore needs  

SciTech Connect

The design of a new two-phase flow laboratory in Norway is discussed. The laboratory, the largest of its kind in the world, is experimenting with the possiblity of transporting both crude oil and natural gas simultaneously through the same pipeline - eliminating the need for offshore separation equipment. The near full scale test unit is arranged as a closed loop and consists of a 400-meter horizontal section of 8 in. diameter pipe terminating in a vertical riser 50 meters high. At the top of the riser, the two-phase flow enters a separator, where oil and gas are separated and returned through separate pipelines to the starting point of the test pipe.

Not Available

1984-05-01

149

Offshore arctic structure  

SciTech Connect

An apparatus is disclosed for minimizing the horizontal forces on an offshore arctic structure due to ice movement. The structure includes a base portion, sloped side walls and a smooth, unobstructed portion. The structure is substantially submerged in a body of water with the top portion at or near the water surface permitting floating ice sheets which strike the side walls to flex slightly upward and advance along and over the structure without substantially destroying the overall integrity of ice sheet. In this manner, the horizontal forces on the structure resulting from the ice sheet are minimized due to the elimination of a crushing failure mode of the ice sheet commonly associated with conventional offshore arctic structures.

Weiss, R.

1983-08-09

150

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

NASA Astrophysics Data System (ADS)

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

Marok, Abbas; Reolid, Matías

2012-11-01

151

Arctic offshore platform  

SciTech Connect

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.

Bhula, D.N.

1984-01-24

152

Offshore finds inspire optimism  

SciTech Connect

The author reviews the oil market in Australia and the Pacific. Some of the highlights are: Australia/Pacific drilling hit 308 in 1987; about 300 seen for 1988; Offshore holds action in New Zealand, while onshore Papua makes news; Reduced taxes, relaxed foreign investment rules aid Aussie development work; Four solid solid discoveries made in Papua's Southern Highlands in 18 months; and Austrialia and New Zealand enact industry degregulation measures.

Not Available

1988-08-01

153

Sequential biostratigraphy of the San Jose-1, Puerto Estrella-1, Santa Ana-1, Uashir-1, and Jarara-1 offshore wells, Guajira Peninsula Colombia  

SciTech Connect

Sequence stratigraphical analysis of the San Jose-1, Puerto Estrella-1, Santa Ana-1, Santa Ana-1, Uashir-1, and Jarara-1 offshore wells located in the Portete area, Guajira Peninsula, provide insight into the development and distribution of reservoirs and seals and allows for a finer stratigraphic resolution and correlation than previous available. The sequence stratigraphical interpretation is based on the interpretation of detailed biostratigraphical analysis, the parasequence stacking patterns from the wireline logs, sedimentological data, and seismic stratigraphical interpretation. The Eocene to Pliocene sediments of the Portete wells were deposited for the most part in outer shelf (shelf-slope break) to upper bathyal, disoxic to anoxic environments. Important reservoir development is formed by lowstand slope and basin floor fans interpreted to correspond to the Early Miocene TB1, 1.4 and 1.5, the Middle Miocene TB2 2.3 and 2.4 sequences, and to the Late Eocene to Early Oligocen TA4 supercycle.

Perez, L. (HOCOL S.A., Cartagena (Colombia))

1993-02-01

154

Chevron sets offshore records  

SciTech Connect

Chevron U.S.A. overcame numerous logistical and engineering problems to drill its offshore wildcat in Destin Dome Block 422. Besides being an operational success, the resulting well established two drilling records: The deepest well ever drilled from a floating drilling rig. The longest and heaviest string of casing run from a floating vessel. Chevron drilled the well to a total depth of 22,222 ft, which surpassed the previous offshore record well depth of 21,872 ft, drilled on Georges Bank offshore New England in 1977. A record 19,260-ft tapered string of 9 5/8- and 10-in. casing was run and landed in the well. Indicator weight of the casing string was 1,050,000 lb. The Block 422 wildcat - located 64 miles southwest of Panama City, Fla., in 674 ft of water - was drilled to evaluate Chevron acreage in one of the few remaining frontier areas in the Gulf of Mexico. Chevron drilled the well, which remains a tight hole, to determine if the area is geologically similar to Mobile Bay to the west.

Moore, S.D.

1986-05-01

155

Offshore Petroleum Discharge System (OPDS)  

Microsoft Academic Search

In response to the requirement to provide large quantities of petroleum products for forces ashore, from tankers offshore without port facilities, the Naval Sea Systems Command has developed and demonstrated the Offshore Petroleum Discharge System (OPDS). OPDS is capable of delivering 1.2 million gallons of product per day from a tanker moored four miles offshore. The system is largely off-the-shelf

J. Exell

1987-01-01

156

California offshore enters new era  

SciTech Connect

California's offshore industry offers the prospect of the discovery and development of giant oil fields. Two offshore fields, Hondo in the Santa Barbara Channel and the Beta field in San Pedro Bay, have helped push the state's production to an all-time high, and the upcoming output from additional OCS fields should keep this progress going steady. Signs point to the development of significant oil reserves in the offshore area extending northward from Point Conception through the offshore portion of the Santa Maria basin. Chevron USA has hinted big oil finds. Additional exploration is expected in the Monterey formation. (DP)

Rintoul, B.

1982-02-01

157

Offshore~WMEP - Monitoring offshore wind energy use  

Microsoft Academic Search

Offshore wind energy use is commonly suggested to play an important role in future electricity supply. However, long-term experience with thousands of onshore wind turbines explicitly hint on possible barriers for a save, efficient, economic and user friendly supply relying on offshore wind energy. A national German programme shall on the one hand support the wind energy branch improving technology

P. Lyding; S. Faulstich; B. Hahn; D. Callies

158

Offshore sand resources for coastal erosion control in Louisiana  

SciTech Connect

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

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

1990-09-01

159

Improved thermoplastic materials for offshore flexible pipes  

SciTech Connect

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

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

1988-08-01

160

Offshore outlook: the American Arctic  

SciTech Connect

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.

Jahns, M.O.

1985-05-01

161

Offshoring”: How big an issue?  

Microsoft Academic Search

Spurred by the political debate in the US and several high-profile corporate moves, “offshoring” has become a lively topic of discussion. This paper by Grant Colquhoun, Keith Edmonds and David Goodger tries to put recent developments in context and argues that “offshoring” should be seen as part of a long-standing and largely beneficial trend of international specialisation. In the short

Grant Colquhoun; Keith Edmonds; David Goodger

2004-01-01

162

Overview of Offshore Wind Technology  

Microsoft Academic Search

Over the past 10 years, offshore wind energy has become a major focus of European wind energy research and deployment. Although current technology has been based mainly on land-based wind turbine designs, more turbines are being designed specifically for offshore applications. New standards have been developed to address the unique design environment imposed by loading from both turbulent wind acting

W. Musial; J. Jonkman

163

California offshore enters new era  

Microsoft Academic Search

California's offshore industry offers the prospect of the discovery and development of giant oil fields. Two offshore fields, Hondo in the Santa Barbara Channel and the Beta field in San Pedro Bay, have helped push the state's production to an all-time high, and the upcoming output from additional OCS fields should keep this progress going steady. Signs point to the

Rintoul

1982-01-01

164

Offshore platform structual accessment system  

SciTech Connect

A system for assessing the structural integrity of offshore drilling platforms employs structural moment detector and associated electronics, microprocessor and software, which monitors the condition of the offshore platform structure and continuously provides useful information concerning the effects of external forces on the structure and its remaining life.

Scott, D.R.; Rhoades, T.S.

1984-02-28

165

Offshore platform structual accessment system  

Microsoft Academic Search

A system for assessing the structural integrity of offshore drilling platforms employs structural moment detector and associated electronics, microprocessor and software, which monitors the condition of the offshore platform structure and continuously provides useful information concerning the effects of external forces on the structure and its remaining life.

D. R. Scott; T. S. Rhoades

1984-01-01

166

Offshore Drilling From Ice Platforms  

Microsoft Academic Search

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

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

1976-01-01

167

Towers for Offshore Wind Turbines  

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

168

Evaluation of offshore stocking of Lake Trout in Lake Ontario  

USGS Publications Warehouse

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 targets.

Lantry, B. F.; O'Gorman, R.; Strang, T. G.; Lantry, J. R.; Connerton, M. J.; Schanger, T.

2011-01-01

169

Stratigraphic and paleoecologic criteria that distinguish coseismically submerged from gradually submerged tidal wetland deposits, Oregon and Washington  

SciTech Connect

Widespread buried tidal-wetland soils exposed in outcrop in southern Washington and northern Oregon suggest that sudden coastal subsidence accompanied great (M>8) Cascadia subduction zone earthquakes at least twice in the past 2,000 years. But interpretation of the estuarine stratigraphic record along the subduction zone is complicated by the interplay of many coastal-sedimentation and sea-level factors found on passive as well as active continental margins. In this presentation, the author outlines-some simple models of sea-level and land-level change along subduction zone coasts, explain how these types of changes might be recorded in the tidal-wetland stratigraphic record, compare stratigraphies from the active-margin coasts of Oregon and Washington with stratigraphies from similar sites along passive continental margins in North America and Europe, and identify criterion that can help distinguish stratigraphic sequences produced by gradual sea-level change from those that may have been produced by coseismic subsidence. Field stratigraphic data alone are an inadequate basis for mapping the coastal extent of past great earthquakes -- only through detailed paleoecologic and dating analyses can one test proposed models of crustal subsidence and recovery during great earthquakes. Rigorous testing of such models is essential if the coastal paleoseismic record is to be used in forecasting the timing and magnitude of future subduction zone earthquakes in Oregon and Washington.

Nelson, A.R. (Geological Survey, Denver, CO (United States))

1993-04-01

170

Proceedings of the fifth international offshore mechanics and Arctic engineering (OMAE) symposium. Volume 3  

SciTech Connect

This book presents the paper given at a symposium on offshore platforms. Topics considered at the symposium included tension leg platforms, tether damage, mechanical vibrations, seismic effects, guyed towers, nonlinear characteristics, wave forces, jack-up drilling units, design, impact strength, barges, hoists, remotely-controlled underwater vehicles, buckle initiation in damaged subsea pipelines, flexible marine risers, offshore cables, hydrodynamics, fatigue properties of mooring chains, underwater inspection systems, offshore accidents, quality assurance, safety, deep water gravity platforms, reinforced concrete, foundations, and leak testing.

Chung, J.S.; Yoshida, K.; Sparks, C.P.; Tsahalis, D.T.

1986-01-01

171

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

Microsoft Academic Search

The distribution in space and time of liquid water on Mars is relevant to astrobiology and astroclimatology. To date, most orbital observations that attest to past fluvial and lacustrine activity on Mars have been dedicated to surficial landforms (i.e., drainage networks and depositional fans). Here we report an unprecedented identification of typical stratigraphic architectures made in Mars Global Surveyor Mars

Gilles Dromart; Cathy Quantin; Olivier Broucke

2007-01-01

172

3-D seismic has renewed the search for stratigraphic traps  

Microsoft Academic Search

Exploration activity has been stimulated in two Lower Permian oil plays of the West Texas Permian basin by a string of economically successful well completions beginning in early 1991. This paper reports that stratigraphic oil targets in each of these trends were identified by new geologic analysis and three dimensional (3-D) seismic methods. The locations of these discoveries are shown.

C. F. Garvey; W. R. Gibson

1992-01-01

173

Middle Devonian (Eifelian) carbonates, Appalachian Basin: A new stratigraphic synthesis  

Microsoft Academic Search

Carbonate-dominated strata equivalent to the Onondaga Formation of New York are widely known across eastern North America, from the James Bay Region of Ontario to southeastern Quebec to Georgia to Illinois. Relationships between Onondaga-equivalent strata within the Appalachian Basin itself, however, have been poorly understood. Detailed stratigraphic study of interbedded limestones and calcareous shales of the Selinsgrove Member (Needmore Formation)

C. A. Ver Straeten; C. E. Brett

1994-01-01

174

Factors controlling the stratigraphic evolution of eastern Brazil basins  

Microsoft Academic Search

The east Brazilian marginal basins offer the best opportunity for understanding the interaction between geological processes and stratigraphic response for Atlantic-type margins. Tectonic subsidence, eustatic changes of sea level, and paleoclimate are the factors that primarily control the nature of the sedimentary infill. Two tectonic stages - rift and thermal - are attributed to lithospheric extension as deduced from crustal

H. K. Chang; R. O. Kowsmann; A. M. Figueiredo; L. G. Aranha

1987-01-01

175

Method for generating reservoir models utilizing synthetic stratigraphic columns  

US Patent & Trademark Office Database

The present invention incorporates the use of geophysical, geological and formation evaluation data to develop synthetic stratigraphic columns based on depositional rules and sedimentary stacking patterns. The present invention utilizes dynamic assignment and matching whereby the synthetic columns can be easily conformed throughout the reservation characterization process as geological data becomes available.

Wilkinson; David A. (Concord, CA); Xie; Deyi (San Ramon, CA)

2010-04-27

176

Understanding organizational capabilities for effective offshoring  

Microsoft Academic Search

In the current competitive environment, the question is no longer whether or not to go offshore, but in determining what should be offshored and how it should be offshored, while keeping the value proposition for the organization as a whole coherent. The decision to offshore work to locations such as India and China may often be initially driven by the

Petra Edoff; Jayakanth Srinivasan

2011-01-01

177

Interpretation of biostratigraphic data at a sequence stratigraphic scale  

SciTech Connect

Recent advances in sequence stratigraphic concepts provide a framework within which biostratigraphic data can be used in conjunction with other stratigraphic tools in an integrated approach to stratigraphic analysis. Sequence stratigraphic concepts suggest that lithologic sections are composed of a succession of unconformity-bounded units or sequences. These sequences can, in turn, be subdivided into systems tracts bounded by flooding surfaces or maximum flooding surfaces. Three systems tracts comprise a sequence: the lowstand or shelf margin systems tract at the base, followed by the transgressive systems tract, and the highstand systems tract. On continental margins with a discrete shelf/slope break, deep-sea submarine fans, shelf-margin deltas, and incised-valley fills characterize the lowstand systems tract. On ramp-like continental margin, the lowstand systems tract is characterized by basinally-isolated lowstand shorelines with or without preserved incised-valley feeder systems. The transgressive systems tract has backstepping shorelines and estuarine fill of incised valley systems. The highstand systems tract is has forestepping depositional systems and widespread floodplain development. A large amount of the structure in the stratigraphic distribution of fossils can be attributed to sequence architecture. This structure can be statistically delineated in terms of a hierarchy that is independent of both fossil group and geological age. The definition of [open quotes]biological analogs[close quotes] of systems tracts reduces the complexity of paleontological census data to a set of (1) internal characteristics within genetic units and (2) boundary conditions at stratal discontinuities. Different taxon groups should display unique and repeatable patterns within different systems tracts and at stratal discontinuities within a basin, providing a new perspective of paleontological data across a spectrum of applications in sequence characterization and correlation.

Goodman, D.K. (ARCO Oil Gas Company, Midland, TX (United States)); Posamentier, H.W. (ARCO Exploration and Production Technology, Plano, TX (United States))

1993-02-01

178

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

SciTech Connect

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

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

1996-01-01

179

Arctic and offshore research: Technology status report  

SciTech Connect

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

Not Available

1988-01-01

180

GNULEX - new online USGS database of stratigraphic nomenclature for US western interior  

Microsoft Academic Search

Accurate and up-to-date information on the definitions of stratigraphic units is essential to both industry and academic activities in the earth sciences. In order to encourage accurate use of stratigraphic nomenclature, they are compiling a new database - GNULEX - which contains comprehensive information on stratigraphic units of the US Western interior (from the Mississippi River to the western borders

M. E. MacLachlan; W. A. Bryant; L. M. Stone; T. W. Judkins

1988-01-01

181

Construction of Large Offshore Structures.  

National Technical Information Service (NTIS)

The engineering and construction of offshore structures, such as steel jackets, mobile drilling rigs, and artificial islands, are one of the main fields of NKK's activities in large steel structures. The paper, describes NKK's contribution in the fields, ...

K. Tsuruta K. Azuma O. Inokoshi T. Naksume H. Ito

1985-01-01

182

State of the art review of oil containment barriers for use at offshore terminals  

Microsoft Academic Search

A review of information on oil barriers suitable for use offshore has been conducted. The technical literature, data from manufacturers and interviews with cognizant personnel at research, test and evaluation agencies, all through June, 1973 have been reviewed. Environmental conditions under which oil containment barriers at offshore oil terminals will be expected to operate effectively have been determined. The problem

Mainville

1973-01-01

183

Seismic expressions of Monterey Formation diagenesis: examples from offshore California  

SciTech Connect

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.

Roy, M.B.

1988-03-01

184

High-resolution records of location and stratigraphic provenance from the rare earth element composition of fossil bones  

NASA Astrophysics Data System (ADS)

Bone apatite acts as a natural, timed sampling device, scavenging trace elements from local pore waters over timescales of ca. 1 50 ka. The rare earth element (REE) and U/Th composition of fossil bones reflects associated pore water compositions during the period of recrystallisation. The REE composition of fossil bones is controlled by partitioning of REE between pore waters and particle surfaces, and the REE composition of fossil bones reflects the REE composition of pore waters which vary spatially and temporally. Light REE are preferentially sorped onto particle surfaces, thus the high La/Yb values seen in many bones from coastal marine and aeolian environments are best explained by release of REE from light REE-enriched particles to local pore waters and subsequent immobilisation in recrystallising bones. The REE compositions of bones recovered from pedogenically altered diatomite sediments of the Olorgesailie Formation of southern Kenya vary over spatial scales of less than 10 m. Location accounts for 48% of the observed variation in bone chemistry and bones recovered from eight discrete excavations within the same time-equivalent stratigraphic layer can be assigned to their excavation location with >70% accuracy based on a discriminant analysis of REE, U, and Th composition. Despite this within-layer variation, bones recovered from different stratigraphic horizons within the Olorgesailie Formation can also be distinguished on the basis of their trace element composition. Bones recovered from four stratigraphic horizons spanning ca. 0.5 million years were assigned to their correct stratigraphic layer with >90% accuracy. Where sedimentological conditions are favourable, the trace element composition of fossil bone may be used to test stratigraphic provenance and burial location in excavated bone with a temporal resolution of <10 ka and a spatial resolution of <10 m. The trace element composition of fossil bone may also be used to investigate the accumulation history of vertebrate assemblages and to reconstruct pore water variability across land surfaces.

Trueman, C. N.; Behrensmeyer, A. K.; Potts, R.; Tuross, N.

2006-09-01

185

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

186

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

NASA Astrophysics Data System (ADS)

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

Dromart, Gilles; Quantin, Cathy; Broucke, Olivier

2007-04-01

187

Probabilistic stratigraphic alignment of Pleistocene d18O records  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

188

Stratigraphic dipmeter interpretation of turbidite sequences, Gulf of Mexico  

Microsoft Academic Search

High-resolution dipmeter logs have been compared to conventional and sidewall cores from Gulf of Mexico turbidite depositional sequences. These calibrations, conjunction with seismic and conventional log data, allow numerous stratigraphic interpretations from dipmeter data. Bedding styles and lithological information can be interpreted from resistivity character and vertical dip progressions. Examples in sand-rich deposits demonstrate (1) thin-bedded vs. thick-bedded or massive

Pettingill

1989-01-01

189

Paleoclimate controls on stratigraphic repetition of chemical and siliciclastic rocks  

SciTech Connect

Climate is a primary control on sediment flux from continental sources into sedimentary systems. In warm climates, siliciclastic input is greatest under highly seasonal rainfall. Nonseasonal conditions favor formation of end member chemical rocks; perennially wet climates are conductive to coal formation, whereas dry climates produce carbonates and/or evaporites. Stratigraphic repetition of siliciclastic and chemical rocks therefore appears to be related to paleoclimate cycles as well as to transgressive-regressive events and tectonics.

Cecil, C.B. (Geological Survey, Reston, VA (USA))

1990-06-01

190

Alaskan Peninsula Cenozoic stratigraphy: stratigraphic sequences and current research  

Microsoft Academic Search

Geology of the Alaska Peninsula-Island Arc and Continental Margin, by C.A. Burk, is the principal reference for stratigraphic studies on the Alaska Peninsula. Burk mapped the Phanerozoic stratigraphy and provided a geologic history and structural interpretation of the area between Wide Bay and Unimak Island. Cenozoic rocks were mapped as three unconformity-bounded sequences. Recognition of specific formations was difficult due

J. M. Armentrout

1985-01-01

191

Offshore industry executives meet  

SciTech Connect

The future of the Gulf of Mexico is tied to the overall future of oil/gas on the international market as it relates to the US. Conquering this last frontier, possibly only through development of technology, was one of the themes covered in the 21st Annual Meeting of the National Ocean Industries Association held in early April, 1993 in Washington, D.C. Oil is the major source for foreign exchange but there are major uncertainties in predicting the future. The swing (imports vs. exports) is two million barrels per day. The big oil users (heavy industry) have reduced consumption. The last big uncertainty is the environmental policies of the West. Development of resources in the Gulf was the third record year in a row in 1992. The potential for hydrocarbon discoveries is significant, a substantial number of new fields have been made and significant discoveries are likely to continue. More than 100 trillion cubic feet of natural gas lies undiscovered offshore - 35% of undiscovered domestic resources. The oil potential exceeds nine billion barrels, more than any other basin except Alaska.

Burns, R.F.

1993-05-01

192

Offshore well support miniplatform  

SciTech Connect

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.

Blandford, J.W.

1987-07-14

193

46 CFR 126.170 - Carriage of offshore workers.  

Code of Federal Regulations, 2010 CFR

... 2009-10-01 false Carriage of offshore workers. 126.170 Section 126...DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS INSPECTION AND CERTIFICATION... General § 126.170 Carriage of offshore workers. (a) Offshore...

2009-10-01

194

Recognition of a thin stratigraphic trap by seismic reflection character analysis  

SciTech Connect

The Cretaceous Cardium Formation, Alberta, Canada, which produces oil and gas from thin stratigraphic traps comprising coastal and offshore shelf sand-ridge deposits, appears as railroad tracks on seismic sections. Ninety-seven seismic lines were examined over a 10,000 km/sup 2/ area. Here, the Cardium is divided into the Cardium Sand and the overlying Cardium Zone, both of which are 15-50 m thick. The Cardium Sand systematically grades eastward from (a) shoreface-strandplain massive sandstones to (b) inner-shelf sandstones encased in shale. The Cardium zone grades eastward from (a) marginal marine/inner-shelf sandstones (< 10 m thick) encased in shale to (b) shelf shales. Two major reflection patterns characterize the Cardium Formation. One consists of two high-amplitude reflections spaced 20-30 m apart, and the other consists of a single reflection; further subdivision is possible on the basis of reflection amplitude. Arealy, these patterns correlate with the regional distribution of sediment facies described above. Reflection patterns of 26 1-D seismic models generated from sonic logs correlate with those of the field seismic data thus allowing interpretation of the field data in terms of sedimentary facies. Thickness of the Cardium Zone and number and thickness of sandstone beds in the Zone were found to control seismic reflection patterns. The double reflection pattern occurs where the Cardium Zone is more than 24 m thick and contains shelf sandstone beds encased in shale. A single reflection, generated from the Cardium Sand, occurs where the zone is less than 24 m thick and lacks sandstones. These relationships can be used to detect and map potential sandstone reservoirs on seismic records.

Slatt, R.M.; Lighty, K.; Robinson, J.

1985-02-01

195

Stratigraphic source and depth into bedrock control composition of ground water across a buried anticline in central Illinois  

SciTech Connect

Buried beneath glacial drift in Coles, Douglas and Champaign Counties, seven stratigraphic units have been tapped for ground water across a small (ca. 10 x 20 mi.) doubly-plunging anticline, part of the LaSalle Anticlinal Belt. Analyses of groundwater from 78 wells in these units have been obtained from the Illinois State Water Survey's Ground-Water Quality Database. Bedrock sources for the water have been determined from well depth, thickness of drift, and the Geologic Map of the US. Piper diagrams have been prepared for all data, by stratigraphic unit, and by depth of well in each unit. Water types, using the convention of > 50% on a milliequivalents per liter basis to determine dominant cation and anion names, include 38 no dominant cation bicarbonate samples, 33 sodium bicarbonate, 5 sodium chloride and 2 calcium bicarbonate samples. Principal variation among cation composition involves presence of Na + K whereas Mg/Mg + Ca remains relatively constant at 43% (s.d. 4%). Groundwater composition tends to be lower in Na+K and Cl from P[sub 3] and higher in older units. A Chi Square test rejects the hypothesis of independence of water type and stratigraphic unit. Similarly, groundwater composition tends to be lower in Na+K and Cl from P[sub 3] and higher in older units. A Chi Square test rejects the hypothesis of independence of water type and stratigraphic unit. Similarly, groundwater composition tends to be lower in Na+K and Cl from shallower wells and higher from deeper wells. A Chi Square test rejects (P of .0001) the hypothesis of independence of water type and depth of well into bedrock.

DeCastro, R.R.; Corbett, R.G. (Illinois State Univ., Normal, IL (United States). Dept. of Geography-Geology)

1994-04-01

196

Off-Shore Wind Power Plants.  

National Technical Information Service (NTIS)

Information is presented concerning the offshore wind power availability in the Baltic Sea; and economics, specifications, and environmental considerations for large offshore wind power plants. (ERA citation 06:004734)

R. Hardell C. Olsson L. Ljung

1979-01-01

197

Geotechnics of Fixed Offshore Drilling Platforms.  

National Technical Information Service (NTIS)

Fixed offshore-structures are widely used for exploration and exploitation of undersea oil and gas resources. The object of this report is to survey the general geotechnical design principles and foundation technics of fixed offshore-structures. Additiona...

J. Toernqvist

1984-01-01

198

Foam pigs solve pipe cleaning problems offshore Brazil  

SciTech Connect

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

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

1995-10-02

199

Steel Plate with Superior HAZ Toughness for Offshore Structures,  

National Technical Information Service (NTIS)

In order to develop steel plate with excellent HAZ toughness for offshore structures, a study was made on the dominating factor for toughness, particularly CTOD. In the CTOD test specimens of welded joints, the majority of cracks were initiated from the c...

T. Haze S. Alhara Y. Ohno K. Uchino Y. Kawashima

1987-01-01

200

Proceedings of the nineteenth annual offshore technology conference. Vol. 1  

SciTech Connect

This book presents the papers given at a conference on offshore platforms. Topics considered at the conference included soil-structure interactions, foundations, hydrodynamics, remotely operated vehicles, wave forces, seismic surveys, morrings, marine risers, steel platform repairs, underwater welding, underwater inspections, wave equations, well completion, damping, anchors, field tests, mechanical vibrations, and hydraulic equipment.

Not Available

1987-01-01

201

Submerged Coastal Offshore Mussles Aquaculture System (SCIMAS): A Mulitidisciplinary Approach.  

National Technical Information Service (NTIS)

This report summarizes the activities and findings during the final period of a two year effort to study the grow-out of mussels offshore. The site of the experiment was the 'Buoy Farm' of the Woods Hole Oceanographic Institution (WHOI), a charted test ar...

W. Paul M. Grosenbaugh

1999-01-01

202

Proceedings of the 22nd annual offshore technology conference  

SciTech Connect

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

Not Available

1990-01-01

203

Prediction of Weather Operating Windows for Offshore Drilling Vessels  

Microsoft Academic Search

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

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

1983-01-01

204

Stratigraphic and structural interpretation with 3-D seismic coherence  

SciTech Connect

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

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

1996-06-01

205

Punctuated Stratigraphic Appearance of Cold-Water Coral Reefs  

NASA Astrophysics Data System (ADS)

Existing and new data acquired with an AUV document a high abundance of cold-water coral mounds in the bottom of the Straits of Florida (SoF). These mounds display a large variability of shapes and heights. The abundance and variability encountered in these and modern cold-water coral mounds elsewhere is in stark contrast to lack of reported ancient cold-water coral reefs. Furthermore, the stratigraphic distribution suggests that cold-water corals punctuate the stratigraphic record with times of bloom and times of near complete absence. In the Florida Bahamas region, for example, the stratigraphic distribution is non-uniform. Preliminary age dating of the modern coral mounds produce ages of a few hundred to 1300 years for corals at the surface of the mounds. Sub-bottom profiles and seismic data across the investigated mound fields reveal that the "modern" mounds root in Pleistocene strata but are absent in the Pliocene strata below. Cores taken during ODP Legs 101 and 166 in the SoF confirm the punctuated appearance as deep-water coral rubble was penetrated only in the Pleistocene and in the upper Oligocene strata. The vast occurrence of Oligocene cold-water coral mounds is also visible on a 2-D seismic line in the northern SoF and on a 3-D seismic survey in the southwestern portion of the SoF. In this latter data set a mid-Miocene and the base of Tertiary seismic horizon also image mounded features. These spikes in reef development indicate that environmental conditions were only occasionally favorable for reef growth. The punctuated appearance is surprising as the core and seismic data document continuous current activity since the late Miocene in the SoF. We speculate that the "modern" bloom of cold-water coral reefs in the Pleistocene coincides with the onset of the large barrier reef systems in the Australia and Belize.

Eberli, G. P.; Correa, T.; Massaferro, J. L.

2008-05-01

206

Maritime and offshore structure maintenance  

SciTech Connect

This volume provides the most up-to date material available on methods of keeping maritime installations operational. It also draws out the exceptionally valuable expertise that has been gained from servicing the major installations in the North Sea and elsewhere in the world. Subjects cover maintenance and repair including a detailed analysis of structural maintenance on specific structures. Papers include expertise in North Sea structures, corrosion protection of a North Sea platform, maintenance of ports overseas, East Africa, low maintenance concrete and maintenance of steel offshore structures. Guidelines are also included for the inspection and maintenance of marine facilities and offshore installations.

Not Available

1986-01-01

207

Climate and offshore energy resources  

NASA Astrophysics Data System (ADS)

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

Twitchell, P. F.

1980-12-01

208

Offshoring in the New Global Political Economy  

Microsoft Academic Search

abstract? This essay challenges claims by economists and management scholars that ‘offshoring’ is simply another form of trade with mutual benefits. I argue that reducing wages through offshoring leads to wealth creation for shareholders but not necessarily for countries and employees, and that many displaced workers have difficulty ‘trading up’ to higher skilled jobs. Offshoring is a new phenomenon that

David L. Levy

2005-01-01

209

OFFSHORE ARCTIC PIPELINE OIL SPILL RISK ASSESSMENT  

Microsoft Academic Search

While offshore arctic pipelines have been under consideration for more than 25 years, few have been built. Renewed interest in offshore arctic oil and gas has necessitated the design of pipelines capable of both overcoming the technical challenges of the arctic offshore environment and minimizing the risk to it. This paper describes a quantitative risk assessment completed by BMT Fleet

A. Dinovitzer; R. Lazor; D. Hinnah

2004-01-01

210

Offshore QRA and the ALARP principle  

Microsoft Academic Search

A discussion is presented of the use of QRA within a requirement, of the UK offshore safety case regime, to demonstrate that risks from offshore major accidents are ALARP. General considerations are given to uncertainties in failure and incident data, assumptions and consequence methodologies within the analysis element of offshore QRA. The validity of risk results arising from the analysis

Stan Schofield

1998-01-01

211

OMAE 1994. Volume 1: Offshore technology  

Microsoft Academic Search

This is volume 1 of a 5 part proceedings from the 13th International Conference on Offshore Mechanics and Arctic Engineering. Volume 1 deals with Offshore Technology and includes information on ocean waves and energy; hydrodynamic forces; fluid-structure interactions; offshore engineering and design; risers, moorings, and cables, compliant towers; and computational hydrodynamics. The proceedings contain 49 papers covering these topics related

S. K. Chakrabarti; D. Morrison; A. N. Williams; R. C. Ertekin; Hisaaki Maeda; M. S. Pantazopoulos

1994-01-01

212

Measuring safety climate on offshore installations  

Microsoft Academic Search

The human and organizational factors affecting safety were examined on 10 offshore installations using the Offshore Safety Questionnaire. The questionnaire contained scales measuring work pressure and work clarity, job communication, safety behaviour, risk perception, satisfaction with safety measures and safety attitudes. A total of 722 UK offshore workers (33% response rate) from a range of occupations completed and returned the

Kathryn Mearns; Rhona Flin; Rachale Gordon; Mark Fleming

1998-01-01

213

Efficiency Evaluation for Offshore Wind Farms  

Microsoft Academic Search

The offshore wind farm with large capacity and long distance to shore has attracted more and more attention as a promising option in the near future. The large-scale offshore wind farm may be designed with very different configurations, which may cause very different cost, efficiency and reliability. This paper presents different possible configurations for a real offshore wind farm in

Zheng Li; Menghua Zhao; Zhe Chen

2006-01-01

214

Advanced transmission solutions for offshore wind farms  

Microsoft Academic Search

Future offshore wind farms will have large power ratings and will be situated much further offshore than current projects. The associated costs for grid connection will be high. This paper explores alternative methods of grid connection. By creating synergies with other applications for offshore power transmission, the total costs will be lower. Such synergies include the bundling of multiple wind

W. L. Kling; R. L. Hendriks; J. H. den Boon

2008-01-01

215

Reliability Issues of Offshore Wind Farm Topology  

Microsoft Academic Search

The main development trend of wind power generation system is large offshore wind farms with grid connection. Due to extraordinarily high investment, many technical issues yet to be solved and limited experience, the risk of building offshore wind power generation system is always very high. The study presented in this paper takes a view of the effect of offshore wind

Xu Liu; Syed Islam

2008-01-01

216

Here are methods for sizing offshore pipelines  

Microsoft Academic Search

Although sizing an offshore, multiphase pipeline requires basically the same procedures as for onshore lines, complicating factors for offshore pipes include riser inclination angles, temperature differentials, and generally higher heat transfer rates. For a typical offshore pipeline system, SSI uses the Beggs and Brill pressure drop and holdup correlations to illustrate the design procedure, taking into account thermal resistances of

Hein

1983-01-01

217

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

Microsoft Academic Search

In this paper, the author presents several applied as well as fundamental research problems related to the future needs of the offshore engineering. The paper starts out with a detailed discussion of the current uncertainties and constraints. Then, specific research issues on environmental input conditions, on the role of computational fluid dynamics, and on damping and dynamic response are presented.

Sarpkaya

1993-01-01

218

Effects of hull–ice friction coefficient on predictions of pack ice forces for moored offshore vessels  

Microsoft Academic Search

Designers and offshore operators frequently predict pack ice loading on offshore vessels by conducting scale model tests. One factor that can affect pack ice loading is the hull–ice friction coefficient. This research investigates the effect of hull–ice friction coefficients for a moored offshore vessel model and includes ice floe size and ice concentration as additional variables. A method of non-dimensional

Reeni C. Woolgar; D. Bruce Colbourne

2010-01-01

219

On balanced and unbalanced accommodation\\/peat accumulation ratios in the Cretaceous coals from Gates Formation, Western Canada, and their sequence-stratigraphic significance  

Microsoft Academic Search

Coal composition was investigated by means of photometric and maceral analyses on closely spaced lithotype-based strip samples over the full thickness of several paralic coal seams from the Cretaceous Gates Formation of the Western Canadian Sedimentary Basin. The aim of this investigation was to test various methods of identifying accommodation trends in coal and use them to refine sequence-stratigraphic interpretation

C Diessel; R Boyd; J Wadsworth; D Leckie; G Chalmers

2000-01-01

220

Inversion of multiple thermal indicators: Quantitative methods of determining paleoheat flux and geological parameters. III. Stratigraphic age determination from inversion of vitrinite reflectance data and sterane isomerization data  

Microsoft Academic Search

Thermal indicator data are used in an inverse mode to determine ages of stratigraphic horizons simultaneously with paleoheat flux. Results from blind tests on wells with horizon ages ranging from Ordovician through Carboniferous and Jurassic to Miocene indicate that thermal indicator inversions are capable of resolving such ages to within about 10% uncertainty. Results using the inversion procedure with one

J. Pantano; I. Lerche

1990-01-01

221

High resolution sequence stratigraphic concepts applied to geostatistical modeling  

SciTech Connect

Lithofacies simulations using a high resolution 3D grid allow to enhance the geometries of internal heterogeneities of reservoirs. In this study the series simulated were the Ness formation, part of the Brent reservoir in the Dunbar field located in the Viking graben of the North Sea. Simulations results have been used to build the reservoir layering supporting the 3D grid used for reservoir engineering, and also used as a frame to study the effects of secondary diagenetic processes on petrophysical properties. The method used is based on a geostatistical study and integrates the following data: a geological model using sequence stratigraphic concepts to define lithofacies sequences and associated bounding surfaces, well data (cores and logs) used as database for geostatistical analysis and simulations, seismic data: a 3D seismic survey has been used to define the internal surfaces bounding the units, outcrop data: The Mesa Verde formation (Colorado, USA) has been used as an outcrop analog to calibrate geostatistical parameters for the simulations (horizontal range of the variograms). This study illustrates the capacity to use high resolution sequence stratigraphic concepts to improve the simulations of reservoirs when the lack of subsurface information reduce the accuracy of geostatistical analysis.

Desaubliaux, G. [Institut Francais du Petrole, Rueil Malmaison (France); De Lestang, A.P. [Beicip-Franlab, Rueil Malmaison (France); Eschard, R. [Institut Francais du Petrole, Rueil Malmaison (France)] [and others

1995-08-01

222

Towers for Offshore Wind Turbines  

Microsoft Academic Search

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

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

2010-01-01

223

Re-Regulating Offshore Finance?  

Microsoft Academic Search

This article explores global efforts to regulate offshore finance in the wake of international concern about the effects of so-called harmful tax competition, as well as money laundering and terrorist financing (the latter a relatively new category since September 11, 2001). In the mid-1990s, a number of multilateral organizations, from the Organization for Economic Cooperation and Development (OECD) to the

B. Maurer

2008-01-01

224

Designing “quiet” into offshore projects  

Microsoft Academic Search

This paper provides some design guidance to assist in addressing and controlling underwater noise of an offshore project-be it oil rig, wind turbine, tidal power or other structure floating on the water or bottom mounted. The importance of a Plan to address and abate noise in order to achieve an underwater-radiated noise goal will be highlighted. The Plan's elements usually

R. W. Fischer

2010-01-01

225

Method for servicing offshore well  

Microsoft Academic Search

This patent describes a method of servicing a cased offshore well having a subsea blowout preventer stack and a riser extending from said stack to an above-water work area, said blowout preventer stack including sealing rams. It comprises: running a sealing nipple, which is open at its lower end and closed at its upper end except for a wireline packing

C. W. Sauer; M. P. Stockinger; L. K. Moran

1990-01-01

226

The Safety of Offshore Structures  

Microsoft Academic Search

The crude oil exploitation equipment requires a special sustaining metallic structure. In Romania, a country with a long tradition in crude oil exploitation, the height of the drilling equipment rises from 40 to 100 m. In the case of offshore exploitations, the sustaining structure has to be built on a marine platform, which can be fixed or mobile. Although the

Ludovic KOPENETZ

227

Offshore oil: Correctness of perspective  

Microsoft Academic Search

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

1993-01-01

228

Offshore Moorings: An Annotated Bibliography.  

National Technical Information Service (NTIS)

The listing was originally intended as a list of relevant literature for the use by students in the Offshore Moorings Course at Delft University of Technology. Rapid development in the field of mooring design is going on continually. One of the most obvio...

W. W. Massie

1991-01-01

229

Riser for an offshore platform  

Microsoft Academic Search

A riser having a 90° bend at its lower end is installed at an offshore platform by mounting the riser within casing with a horizontal leg from the 90° bend extending through a hole in the wall of the casing and lowering the casing through guide funnels extending inwardly from the framework of the platform. The guides have openings in

R. Jr

1977-01-01

230

Transfer terminal for offshore production  

SciTech Connect

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.

Arnaudeau, M.

1983-02-01

231

Deriving a framework for the hydrocarbon potential offshore Namibia: An ideal case for using seismic and sequence stratigraphy?  

SciTech Connect

The passive continental margin offshore Namibia remains one of the few relatively unexplored, frontier areas for hydrocarbon exploration. The availability of 14,300km of speculative, non-exclusive seismic reflection dam has provided the opportunity to build up a sequence stratigraphic framework for this margin, with a view to hydrocarbon play analysis and prediction. The high seismic resolution of the data allows the definition of a number of megasequences. each representing a major phase of basin evolution. The post-rift prograding wedge (MS50) can be divided into a lower MS50a (Aptian - Masianchtian) and an upper MS50b (Ternary) unit. Internally these units are composed of a number of T/R cycles. Isopach maps for MS50a and MS50b have been constructed. The information from these can be supplemented by river system and drainage basin analysis to gain some insight into the type of sediment expected to be deposited offshore at different times during the evolution of the margin. A number of different features can be identified from the data which can help place the post-rift units into a sequence stratigraphic framework. Channel forms and slump-related features are observed which may form in response to relative sea level changes or tectonic triggering. The seismic expressions of these features enables the causative process to be determined. By constructing geohistory curves using a basin modelling program, the structural and stratigraphic evolution of the Namibian margin may be further elucidated. Such geohistories pinpoint the location of possible source rock horizons which, when fed back into the sequence stratigraphic framework, may aid the prediction of potential hydrocarbon plays.

Bagguley, J.G.; Prosser, S.D. [Oxford Brookes Univ. (United Kingdom)

1995-08-01

232

Visual Stratigraphic Correlation and Anaglyph 3-D Visualizations Using GigaPan Imagery: Examples from Western Kansas  

NASA Astrophysics Data System (ADS)

GigaPan images of outcrop, quarry, and roadcut exposures have been captured and are being used to test the efficacy of a novel visual comparison technique in addressing issues of stratigraphic correlation of sub- units within the Upper Cretaceous Niobrara Formation in Rooks, Ellis, Gove, and Trego Counties in northwest Kansas. Through the use of side-by-side implementations of the web-based GigaPan Flash viewer, distinctive individual layers and stratigraphic sequences can be matched in a highly intuitive visual manner. Incorporating adequate quantitative measures of scale is a challenge that remains to be solved before high precision correlation can be done with GigaPan imagery, however semi-quantitative and qualitative preliminary results suggest that this device may become a powerful research tool. Application of the visual correlation technique to the teaching of stratigraphic correlation concepts in the classroom offers a novel and interactive way for students to experience the joy of discovery in a virtual field environment. A method for creating anaglyph GigaPan images with the current GigaPan robot will also be described; the resulting images represent another way to significantly enhance classroom-based virtual field experiences.

Schott, R. C.

2008-12-01

233

Middle Cenozoic benthic foraminiferal biofacies, stratigraphic events, and unconformity-bounded stratigraphic units; key to stratigraphic analysis of active margin basins  

SciTech Connect

An examination of the depositional history of two middle Cenozoic active margin basins in central California provides insights into the relative importance of tectonics and eustasy for controlling large-scale stratigraphic relationships. Both the Cuyama and southernmost San Joaquin basins were analyzed with respect to benthic foraminiferal biofacies, biostratigraphic and lithostratigraphic events, and the nature and extent of regionally important unconformities. The Cuyama basin exhibits two distinct cycles of basin subsidence and filling - one (late Oligocene to early Miocene) associated with the Vaqueros formation and the other (early to late Miocene) associated with the Monterey formation. The San Emigdio area of the southernmost San Joaquin basin exhibits only one major basin cycle (late Oligocene to late Miocene) associated with the Temblor and Monterey Formations. An analysis of the distribution of major unconformities, rapid bathymetric deepenings, periods of peak transgression, major shallow-marine progradational events, episodes of submarine fan development, and fluctuations in foraminiferal biofacies is used to compare basin history in the two areas. The timing of events is not always very well constrained but indicates that both eustasy and tectonics were important in shaping basin history. Several relationships suggest that tectonics is the relatively more important factor in these basins. Depositional history also is a key to understanding benthic foraminiferal biofacies distribution (particularly with respect to three-dimensional distribution of key marker species), which in turn provides insights into benthic foraminiferal biostratigraphy.

Lagoe, M.B.

1988-03-01

234

OWL representation of the geologic timescale implementing stratigraphic best practice  

NASA Astrophysics Data System (ADS)

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

Cox, S. J.

2011-12-01

235

Severe slug flow in offshore flowline/riser systems  

SciTech Connect

Small-scale experiments are described that simulate the unstable two-phase flow pattern of severe slugging often found in offshore flowline/riser systems. In particular, the effects of riser-base supplementary gas lift, flowline orientation, and liquid viscosity have been examined. To place the tests in perspective, the physics of severe slugging is discussed, including a method for scaling between model and prototype situations. Test results are compared with a simple hydrodynamic computer model.

Pots, B.F.M.; Bromilow, I.G.; Konijn, M.J.W.F.

1987-11-01

236

Severe slug flow in offshore flowline/riser systems  

SciTech Connect

Small-scale experiments are described which simulate the unstable two-phase flow pattern of severe slugging often found in offshore flow-line/ riser systems. In particular, the effects of riserbase supplementary gas lift, flow-line orientation and liquid viscosity have been examined. In order to place the tests in perspective, the physics of severe slugging is discussed, including a method for scaling between model and prototype situations. Test results are compared with a simple hydrodynamic computer code.

Pots, B.F.M.; Bromilow, I.G.; Konijn, M.J.W.F.

1985-03-01

237

Geographic and stratigraphic distribution of Miocene palynomorphs in north Idaho  

NASA Astrophysics Data System (ADS)

Acetolysis of Early and Middle Miocene sediments from the Clarkia, Idaho, area yielded 3,477 palynomorphs representing 37 taxa from eighteen samples for assemblage analysis. Relative pollen frequency data from various study sites suggest an older Coniferae-Mixed Dicotyledoneae-Pteridophyte Palynomorph Assemblage Zone, and a younger Fagaceae-TCT-Platanus Pollen Assemblage Zone. Two pollen based chronostratigraphic stages are proposed for at least part of the Miocene epoch: an older Clarkian Stage, and a younger Oviattian Stage. Palynomorph stratigraphic range charts document the youngest regional occurrence of Lygodium. Two palynomorph taxa are possible index fossils in the Pacific Northwest: (1) Sigmopollis (Incertae Sedis) for the Oligocene, and (2) Elaeagnus (Elaeagnaceae) for the Late Oligocene-Early Miocene. Palynostratigraphic and assemblage analyses of the fossil bearing sediments confirms prior models for the infilling of Miocene Clarkia Lake, and a regional change from a warm temperature to temperate climate.

Jorstad, R. B.

1983-02-01

238

3-D seismic has renewed the search for stratigraphic traps  

SciTech Connect

Exploration activity has been stimulated in two Lower Permian oil plays of the West Texas Permian basin by a string of economically successful well completions beginning in early 1991. This paper reports that stratigraphic oil targets in each of these trends were identified by new geologic analysis and three dimensional (3-D) seismic methods. The locations of these discoveries are shown. The two Wolfcamp carbonate detrital formations are characterized by clusters of rich oil accumulations in discontinuous reservoir pods that are relatively small in aerial extent. These objectives are generally encountered at drilling depths of about 8,000 to 9,000 ft. 3-D seismic proved to be a cost effective exploration and exploitation technique in these plays.

Garvey, C.F. (Samedan Oil Corp., Midland, TX (US)); Gibson, W.R.

1992-09-01

239

Stratigraphic signature of meso- and macrotidal coastal sand body sequences  

SciTech Connect

Numerous cores up to 4.6 m in length from the Wadden Sea of Germany and Louisa Creek, Queensland coast, Australia show a marked absence of tidal structures although spring tides of these two environments are > 3 m and > 6 m respectively. Both areas accumulate well-sorted sand with small amounts of shell and mud drapes or flasers. In the Wadden Sea tidal bedding is present locally and tidal bundles are present in cores from channel margins where megaripples are prominent. Cores from the tidal flats show ripple cross-strata formed by waves. Cores from Louisa Creek show no tidal bundling and little bidirectional cross-strata although the surface of the sand bodies is dominated by megaripples that reverse direction with the tidal cycles. These data suggest that much of the tidally influenced sedimentation that is preserved in the stratigraphic record will probably not be interpreted as such.

Davis, R.A. Jr. (Univ. of South Florida, Tampa, FL (United States). Dept. of Geology)

1993-03-01

240

Geologic mapping and stratigraphic investigations of the lunar crater Tycho  

NASA Astrophysics Data System (ADS)

We produced a new geologic map and studied important stratigraphic relationships for Tycho crater. This crater is ~102 km in diameter and is located in the southern highlands on the nearside of the Moon. We used high-resolution Lunar Reconnaissance Orbiter Camera (LROC) and Selenological and Engineering Explorer (SELENE) Terrain Camera (TC) images for detailed mapping, stratigraphic investigations, and dating of geologic units with crater size-frequency distribution (CFSD) measurements. In addition, we used Clementine FeO and TiO2 maps [1] and Moon Mineralogy Mapper (M3) [2] data to investigate the mineralogy. CSFD measurements at young lunar craters are important for helping us better understand the impact rate over the last billion years [3]. Melt pools dated with CSFDs on LROC Narrow Angle Camera (NAC) images, show model ages between 24.2 ± 5.6 Ma and 80.0 ± 14.7 Ma, whereas our model age for the ejecta blanket is 119 ± 12 Ma. The apparent absolute model ages measured for melt pools at Tycho are younger than the ejecta blanket. However, the impact melt and ejecta blanket should have formed at about the same time [4]. One interpretation of the discrepancies between the model ages of the melt pools and the ejecta blanket is that they have different target properties, i.e., the melt pools could be less porous and stronger [3,5]. Alternatively, self-secondary cratering might cause differences in CSFDs [6]. Our detailed geological map shows the distribution of melt pools in the study area. In particular, it shows a large coherent melt sheet within the crater, melt pools and flows along the terraced crater rim, and melt pools on the continuous ejecta blanket. The mapped distribution of melt pools is consistent with an oblique impact of the Tycho impactor from the southwest, as proposed by [7,8]. In addition to the distribution, we will also present results of the volume of melt pools associated with Tycho.

Krüger, T.; Hiesinger, H.; van der Bogert, C. H.

2012-04-01

241

Classification of offshore mass movements  

SciTech Connect

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.

Mulder, T. [Inst. Francais de Recherches pour l`Exploitation de la Mer, Plouzane (France). Dept. de Geosciences Marines]|[Ecole Nationale Superieure de Geologie, Vandeuvre-les-Nancy (France). Lab. de Geomecanique; Cochonat, P. [Inst. Francais de Recherches pour l`Exploitation de la Mer, Plouzane (France). Dept. de Geosciences Marines

1996-01-01

242

NDE (Non-Destructive Evaluation) Round Robin. The Evaluation of NDE Techniques for Determining Offshore Structures Integrity.  

National Technical Information Service (NTIS)

The Round Robin Test Program was undertaken to document the abilities of several nondestructive evaluation (NDE) techniques in monitoring the integrity of large, complex structures and, particularly, off-shore oil platforms. The test program required advo...

R. E. Dame H. A. Warren

1983-01-01

243

NDE (Non-Destructive Evaluation) Round Robin. The Evaluation of NDE Techniques for Determining Offshore Structures Integrity Appendices.  

National Technical Information Service (NTIS)

The Round Robin Test Program was undertaken to document the abilities of several nondestructive evaluation (NDE) techniques in monitoring the integrity of large, complex structures and, particularly, off-shore oil platforms. The test program required advo...

R. E. Dame H. A. Warren

1983-01-01

244

Two offshore Australian crudes assayed  

SciTech Connect

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.

Rhodes, A.K.

1994-05-09

245

Offshore storage and loading system  

SciTech Connect

An offshore loading system is described which was designed for the Statfjord oil field in the North Sea. The system consists of a gravity-base concrete structure supporting a steel deck, an articulated single-point mooring buoy and a pipeline connecting the two. The platform accommodates a group of oil wells, including production, gas injection and water injection. The buoy is designed for maximum safety and maximum capability of accepting tankers in heavy seas.

Flloyd, C.W.

1981-01-01

246

Titanium in offshore oil production  

SciTech Connect

Titanium once thought to be a material used exclusively in aerospace applications, is now a candidate for use in offshore oil production where strength, weight, corrosion resistance, long life expectancy, and ease of fabrication are important. The family of titanium alloys has grown to the extent that there are now materials available to fill many of the needs of this demanding industry. 15 refs., 10 figs., 5 tabs.

Forney, C.E. [Sandvik Special Metals Corp., Kennewick, WA (United States)

1995-10-01

247

Mass Wasting Processes - Offshore Sumatra  

Microsoft Academic Search

Earthquakes are a commonly cited mechanism for triggering submarine landslides that have the potential to generate locally\\u000a damaging tsunamis. With measured runups of over 35 metres in northern Sumatra from the December 26th 2004 tsunami source,\\u000a these runups might be expected to be due, in part, to local submarine landslides. Mapping of the convergent margin offshore\\u000a of Sumatra using swath

D. R. TAPPIN; L. McNeil; T. Henstock; D. Mosher

248

Spectral stratigraphy: multispectral remote sensing as a stratigraphic tool, Wind River\\/Big Horn basin, Wyoming  

Microsoft Academic Search

Stratigraphic and structural analyses of the Wind River and Big Horn basins areas of central Wyoming are in progress. One result has been the development of a new approach to stratigraphic and structural analysis that uses photogeologic and spectral interpretation of multispectral image data to remotely characterize the attitude, thickness, and lithology of strata. New multispectral systems that have only

H. R. Lang; E. D. Paylor

1987-01-01

249

The ANDRILL Initiative: Stratigraphic Drilling for Climatic and Tectonic History in Antarctica  

Microsoft Academic Search

Limited exposures of Cenozoic strata in Antarctica (due to ice cover) and the low number of stratigraphic drillholes on the continental margin has forced geoscientists to interpret ice sheet history from information derived from lower latitude proxy records. Leading paradigms have been driven by the oxygen isotope record from deep-sea cores and eustatic changes inferred from sequence stratigraphic records on

R. Levy; F. Florindo; J. Francis; D. Harwood; T. Naish; F. Niessen; R. Powell; W. Gary

2002-01-01

250

Stratigraphic, Morphologic, and Pedologic Evidence of Large Floods in Humid Environments  

Microsoft Academic Search

Because of the difficulties faced by engineers, planners, and geomorphologists involved in the prediction of very large floods, the use of stratigraphic, morphologic, and pedalogic evidence for recognition of large floods in humid environments is helpful. Coarse gravel lenses in fine-grained alluvium, inverse grading, and clay balls are stratigraphic records of large floods, best preserved in valley reaches with wide

John E. Costa

1974-01-01

251

History of the Celebes Sea Basin based on its stratigraphic and sedimentological record  

Microsoft Academic Search

The stratigraphic and sedimentary history of the Celebes Sea Basin provides the basis for a tectonic model for its evolution which is consistent with new regional plate reconstructions. Cores drilled on Leg 124 of the Ocean Drilling Program (sites 767 and 770) form a stratigraphic record from the basement to the sea floor in just under 800 metres of sedimentary

Gary Nichols; Robert Hall

1999-01-01

252

Offshore oil: Correctness of perspective  

SciTech Connect

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.

Burns, R.F.

1993-05-01

253

Development and evaluation of the offshore and coastal dispersion model  

SciTech Connect

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

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

1985-10-01

254

Geological history of the Flemish Pass Basin, offshore Newfoundland  

SciTech Connect

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

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

1993-04-01

255

OMAE 1993: Proceedings. Volume 1: Offshore technology  

Microsoft Academic Search

This represents volume 1 of a 5 volume series of offshore technology conference proceedings. This particular paper section deals with information relative to wave forces and energy; hydrodynamic forces and their computation methods; fluid-structure interaction; motions of floating offshore and ship structures;risers, moorings, and cables; design of offshore structures and structural mechanics; and re-assessment of jacket structures. This conference was

S. K. Chakrabarti; C. Aage; Hissaki Maeda; A. N. Williams; D. Morrison

1993-01-01

256

Time to Success in Offshoring Business Processes  

Microsoft Academic Search

• \\u000a \\u000a \\u000a This paper contributes to the emerging debate about offshoring of support functions in international business research. We\\u000a analyze the success of offshoring activities and focus on the time a firm takes to achieve its expected cost savings and its\\u000a targeted service level.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a We hypothesize that firm-specific offshoring experience, publicly available knowledge on offshoring, path dependencies, cultural\\u000a distances, and

Thomas Hutzschenreuter; Arie Y. Lewin; Stephan Dresel

2011-01-01

257

47 CFR 22.1007 - Channels for offshore radiotelephone systems.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Channels for offshore radiotelephone systems. 22.1007...CARRIER SERVICES PUBLIC MOBILE SERVICES Offshore Radiotelephone Service § 22.1007 Channels for offshore radiotelephone systems. The...

2009-10-01

258

47 CFR 22.1007 - Channels for offshore radiotelephone systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Channels for offshore radiotelephone systems. 22.1007...CARRIER SERVICES PUBLIC MOBILE SERVICES Offshore Radiotelephone Service § 22.1007 Channels for offshore radiotelephone systems. The...

2010-10-01

259

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

SciTech Connect

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

NONE

1995-12-31

260

The stratigraphic architecture and evolution of the Burdigalian carbonate—siliciclastic sedimentary systems of the Mut Basin, Turkey  

NASA Astrophysics Data System (ADS)

This study describes the coeval development of the depositional environments in three areas across the Mut Basin (Southern Turkey) throughout the Late Burdigalian (early Miocene). Antecedent topography and rapid high-amplitude sea-level change are the main controlling factors on stratigraphic architecture and sediment type. Stratigraphic evidence is observed for two high-amplitude (100 150 m) sea-level cycles in the Late Burdigalian to Langhian. These cycles are interpreted to be eustatic in nature and driven by the long-term 400-Ka orbital eccentricity-cycle-changing ice volumes in the nascent Antarctic icecap. We propose that the Mut Basin is an exemplary case study area for guiding lithostratigraphic predictions in early Miocene shallow-marine carbonate and mixed environments elsewhere in the world. The Late Burdigalian in the Mut Basin was a time of relative tectonic quiescence, during which a complex relict basin topography was flooded by a rapid marine transgression. This area was chosen for study because it presents extraordinary large-scale 3D outcrops and a large diversity of depositional environments throughout the basin. Three study transects were constructed by combining stratal geometries and facies observations into a high-resolution sequence stratigraphic framework. 3346 m of section were logged, 400 thin sections were studied, and 145 biostratigraphic samples were analysed for nannoplankton dates (Bassant, P., 1999. The high-resolution stratigraphic architecture and evolution of the Burdigalian carbonate-siliciclastic sedimentary systems of the Mut Basin, Turkey. PhD Thesis. GeoFocus 3. University of Fribourg, 277 p.). The first transect (Alahan) is on the northwestern basin margin. Here, the siliciclastic input is high due to the presence of a river system. The siliciclastic depocentre migrates landwards during transgressions, creating an ecological window allowing carbonates to develop in the distal part of the delta. Carbonate production shuts down during the regression when siliciclastics return. The second transect (Pirinç) is also situated on the northern basin margin 12 km to the east of the Alahan section. It shows a complete platform-to-basin transition. An isolated carbonate platform complex develops during the initial flooding, which is drowned during a time of rapid sea-level rise and environmental stress, associated with prograding siliciclastics. The shelf margin then retrogrades forming large-scale clinoform geometries and progrades before a major sea-level fall provokes slumping collapse, followed by rebuilding of the shelf margin as sea level rises again. The third transect (Silifke) has a steep asymmetric Pre-Miocene valley-topography, forming a narrow strait, linking the Mut Basin to the Mediterranean. Strong tidal currents are generated in this strait area. Siliciclastic input is low and localised. Eighty metres of cross-bedded bioclastic sands are deposited in a tidal regime at the base. Subsequently, carbonate platforms backstep against the shallow-dipping northern flank, while platforms only develop on the steep southern flank when a firm wide shallow-marine substrate is provided by a bench on the footwall block. The energy of the environment decreases with increased flooding of the strait area. Third-order sequences and higher-order parasequences have been identified in each transect and correlated between transects. Correlations were made using biostratigraphic data and high-resolution sequence stratigraphy in combination with the construction of the relative sea-level curve for each site. The third-order highstands are stacked in a proximal position and separated by exposure surfaces, while the lowstands, deposited in a distal setting, are separated by deep-marine (offshore or subphotic) deposits. The parasequences produce dominantly aggradational and progradational geometries with transgressive ravinement surfaces and exposure surfaces developing at times. Reconstruction of the depositional profile shows that the third-order sequences are driven by relative sea-level oscillatio

Bassant, P.; van Buchem, F. S. P.; Strasser, A.; Görür, N.

2005-01-01

261

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

NASA Astrophysics Data System (ADS)

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

Swanson-Hysell, Nicholas L.

262

Severe Slug Flow in Offshore Flowline\\/Riser Systems  

Microsoft Academic Search

Small-scale experiments are described that simulate the unstable two-phase flow pattern of severe slugging often found in offshore flowline\\/riser systems. In particular, the effects of riser-base supplementary gas lift, flowline orientation, and liquid viscosity have been examined. To place the tests in perspective, the physics of severe slugging is discussed, including a method for scaling between model and prototype situations.

Bert Pots; Ian Bromilow; Martin Konijn

1987-01-01

263

Severe slug flow in offshore flowline\\/riser systems  

Microsoft Academic Search

Small-scale experiments are described which simulate the unstable two-phase flow pattern of severe slugging often found in offshore flow-line\\/ riser systems. In particular, the effects of riserbase supplementary gas lift, flow-line orientation and liquid viscosity have been examined. In order to place the tests in perspective, the physics of severe slugging is discussed, including a method for scaling between model

B. F. M. Pots; I. G. Bromilow; M. J. W. F. Konijn

1985-01-01

264

Fossils out of sequence: Computer simulations and strategies for dealing with stratigraphic disorder  

SciTech Connect

Microstratigraphic resolution is limited by vertical mixing and reworking of fossils. Stratigraphic disorder is the degree to which fossils within a stratigraphic sequence are not in proper chronological order. Stratigraphic disorder arises through in situ vertical mixing of fossils and reworking of older fossils into younger deposits. The authors simulated the effects of mixing and reworking by simple computer models, and measured stratigraphic disorder using rank correlation between age and stratigraphic position (Spearman and Kendall coefficients). Mixing was simulated by randomly transposing pairs of adjacent fossils in a sequence. Reworking was simulated by randomly inserting older fossils into a younger sequence. Mixing is an inefficient means of producing disorder; after 500 mixing steps stratigraphic order is still significant at the 99% to 95% level, depending on the coefficient used. Reworking disorders sequences very efficiently: significant order begins to be lost when reworked shells make up 35% of the sequence. Thus a sequence can be dominated by undisturbed, autochthonous shells and still be disordered. The effects of mixing-produced disorder can be minimized by increasing sample size at each horizon. Increased spacing between samples is of limited utility in dealing with disordered sequences: while widely separated samples are more likely to be stratigraphically ordered, the smaller number of samples makes the detection of trends problematic.

Cutler, A.H.; Flessa, K.W. (Univ. of Arizona, Tucson (USA))

1990-06-01

265

Stratigraphic dipmeter interpretation of turbidite sequences, Gulf of Mexico  

SciTech Connect

High-resolution dipmeter logs have been compared to conventional and sidewall cores from Gulf of Mexico turbidite depositional sequences. These calibrations, conjunction with seismic and conventional log data, allow numerous stratigraphic interpretations from dipmeter data. Bedding styles and lithological information can be interpreted from resistivity character and vertical dip progressions. Examples in sand-rich deposits demonstrate (1) thin-bedded vs. thick-bedded or massive lithologies, (2) subtle layering in sands which are visually massive, (3) parallel-bedded strata vs. pinch and swell bedding, and (4) massive, shaly nonreservoir sands (interpreted to be debris flow deposits). The amount of dip scatter in sands is directly or indirectly related to depositional energy level. Deep-water shales exhibit a range of dip patterns which may be used to differentiate them and thus better understand their significance to fan-related processes. The amount of dip scatter is apparently inversely related to the presence of silty and/or calcareous layers. Shales without substantial layering characteristically have random dip patterns. Turbiditic shales have constant dip, reflecting intercalated clay-rich and siltrich beds; hemipelagic shales of varying CaCO/sub 3/ composition likewise have patterns of constant dip.

Pettingill, H.S.

1989-03-01

266

Stratigraphic placement and age of modern humans from Kibish, Ethiopia.  

PubMed

In 1967 the Kibish Formation in southern Ethiopia yielded hominid cranial remains identified as early anatomically modern humans, assigned to Homo sapiens. However, the provenance and age of the fossils have been much debated. Here we confirm that the Omo I and Omo II hominid fossils are from similar stratigraphic levels in Member I of the Kibish Formation, despite the view that Omo I is more modern in appearance than Omo II. 40Ar/39Ar ages on feldspar crystals from pumice clasts within a tuff in Member I below the hominid levels place an older limit of 198 +/- 14 kyr (weighted mean age 196 +/- 2 kyr) on the hominids. A younger age limit of 104 +/- 7 kyr is provided by feldspars from pumice clasts in a Member III tuff. Geological evidence indicates rapid deposition of each member of the Kibish Formation. Isotopic ages on the Kibish Formation correspond to ages of Mediterranean sapropels, which reflect increased flow of the Nile River, and necessarily increased flow of the Omo River. Thus the 40Ar/39Ar age measurements, together with the sapropel correlations, indicate that the hominid fossils have an age close to the older limit. Our preferred estimate of the age of the Kibish hominids is 195 +/- 5 kyr, making them the earliest well-dated anatomically modern humans yet described. PMID:15716951

McDougall, Ian; Brown, Francis H; Fleagle, John G

2005-02-17

267

Seismic stratigraphic framework of deep central Gulf of Mexico basin  

SciTech Connect

The deep Gulf of Mexico basin is underlain by up to 10 km (33,000 ft) of Jurassic(.) to Holocene layered sedimentary rocks. The multichannel reflection seismic record from the deep Gulf of Mexico was divided into six seismic stratigraphic units for study of the geologic history of this accumulation. The basal Challenger unit (Jurassic (.) to middle Cretaceous) is considered coeval with early basin formation. We interpret it as a deep marine sequence overlying oceanic crust in the central basin and as continental and shallow through deep marine rocks, including thick evaporites, over adjacent transitional crust. The next three units, Campeche, Lower Mexican Ridges and Upper Mexican Ridges, indicate that from the Late Cretaceous through middle Miocene the basin filled progressively from the west and north, most probably with siliceous turbidites interlayered with pelagic deposits. By the late Tertiary, however, salt and shale deformation within thick sedimentary sections along the western and northern margins trapped much of the incoming sediment supply on the shelves and upper slopes. The late Miocene to Pliocene Cinco de Mayo unit, therefore, represents a relatively starved interval. In contrast, the uppermost, or Sigsbee unit, includes the Mississippi Fan, an accumulation up to 3 km (10,000 ft) thick of mainly mass-transported deposits that bypassed the shelf and slope and were deposited directly onto the abyssal plain. In the western and southwestern portions of the deep basin, beyond the fan pinchout, the Pleistocene section is largely a continuation of the Pliocene suspension deposits.

Shaub, F.J.; Buffler, R.T.; Parsons, J.G.

1984-11-01

268

Using borehole images to quantify reservoir quality and stratigraphic distribution  

SciTech Connect

Understanding the distribution of good-quality reservoir rock in a prospective formation is essential to improved reserves computation and maximized production. High-resolution borehole images provide a rapid and efficient method to evaluate reservoir quality over extended sequences. Microconductivity curves from images are evaluated using modal analysis on histograms to establish specific populations. These populations are assigned to electrofacies, which are discriminated using other logs and core data to generate a lithofacies column. Net pay, or sand counts, are computed based on the distribution of log-derived lithofacies. Reservoir distribution is based on the integration of structural and stratigraphic image analyses. This method is applied to two different reservoirs, the first example is of a well developed, valley-fill sequence comprising thick, stacked fluvial-deltaic channel sands. These sands are over 100 ft thick, have >20% porosity, and over 200 md permeability. The distribution and thickness of optimum quality reservoir is random, however. The second example is of multiple, small scale, depositional units between 3 in. and 24 in., which have 15% porosity with >500 md permeability. The net thickness and exact position of high-quality reservoir intervals is not apparent from standard logs, but becomes clear after image analysis.

Roestenburg, J.W. (Schlumberger Geophysics Nusantara, Jakarta (Indonesia))

1994-07-01

269

Relative Age-dating -- Discovery of Important Stratigraphic Principles  

NSDL National Science Digital Library

When piecing together the geologic history of the Earth, geologists rely on several key relative age-dating principles that allow us to determine the relative ages of rocks and the timing of significant geologic events. In a typical Historical Geology class or textbook, instructors/authors briefly discuss the important early researchers in the geological sciences, and then give the name of the stratigraphic principle, useful for relative age-dating of rocks and events, that these 17th and 18th century scientists are credited with discovering. After the instructor/author defines these principles, students are usually shown several examples so they can see how the principle can be applied. But why not start with the examples and let students discover these principles for themselves? Students are split into small groups which each work to discover a different relative age-dating principle. The groups are shown photos and given handouts with drawings of rock outcrops illustrating the various principles. These handouts include worksheets for which they must answer a series of prompts that help lead them to the discovery of their relative age-dating principle. Groups must also invent a name for their principle, and select a spokesperson who will present the group's results to the rest of the class.

Steinberg, Roger

270

Middle Devonian (Eifelian) carbonates, Appalachian Basin: A new stratigraphic synthesis  

SciTech Connect

Carbonate-dominated strata equivalent to the Onondaga Formation of New York are widely known across eastern North America, from the James Bay Region of Ontario to southeastern Quebec to Georgia to Illinois. Relationships between Onondaga-equivalent strata within the Appalachian Basin itself, however, have been poorly understood. Detailed stratigraphic study of interbedded limestones and calcareous shales of the Selinsgrove Member (Needmore Formation) in central Pennsylvania reveals a number of distinctive marker units that are widely traceable throughout the region. Marker units include: a massive limestone; shale-dominated intervals; several thin black shales; the widely recognized Tioga Ash Beds; distinctive yellow to gray clays that represent additional apparent K-bentonite beds; and pyrite nodule-rich intervals. Combined, these form a very distinctive microstratigraphic framework that is widely correlatable across central Pennsylvania. This microstratigraphic framework is directly correlatable into the Onondaga Limestone of central New York, Direct comparison of the New York and Pennsylvania sections permit recognition of four subunits of the Selinsgrove Member that are equivalent to the four members of the Onondaga Formation (Edgecliff, Nedrow, Moorehouse, and Seneca Members). Therefore, it is shown that the Selinsgrove Member of the Needmore Formation is the direct equivalent of the Onondaga Formation of New York.

Ver Straeten, C.A.; Brett, C.E. (Univ. of Rochester, NY (United States). Dept. of Geological Sciences)

1994-04-01

271

The Antrim Shale: Structural and stratigraphic influences on gas production  

SciTech Connect

The Antrim Shale of the Michigan basin is one of the most actively drilled gas plays in the United States. Core analysis, geologic mapping, and core to log correlations of a 9 mi{sup 2} study area in the middle of the present play have defined geologic influences on the location and productivity of Antrim reservoirs. Application of these factors in the design of exploration and development strategies could improve gas recovery from the Antrim Shale. The lower section of the Antrim Shale, containing the present producing horizons, is composed of four lithologies that subdivide the Antrim into facies and parasequences based upon their mineralogy and textural characteristics. The black shales of the producing horizons are characterized by high but variable quartz contents and an extremely fine-grained matrix of muscovite and clays. The black shales are surrounded by two types of gray shale, differentiated by amount and form of carbonates, and a green shale. The type of shale bounding the productive, organic-rich black shales may affect stimulation strategies and their effectiveness. These black shales average 10% but can be as high as 20% TOC by weight. The organic contents impart a distinctive signature to gamma ray logs that enabled isopach, lithofacies, and structural mapping of the Antrim. Correlated with available production data, the maps reveal distinct trends suggesting that well performance is influenced by both structural and stratigraphic controls.

Manger, K.C.; Oliver, S.J.P. (ICF Resources Incorporated, Fairfax, VA (United States)); Scheper, R.J. (Gas Research Inst., Chicago, IL (United States))

1991-03-01

272

Eolian paleotopographic highs as stratigraphic traps: origin and distinction  

SciTech Connect

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

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

1985-02-01

273

Horizontal drilling in the Austin Chalk: Stratigraphic factors  

SciTech Connect

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

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

1990-05-01

274

Offshore drilling and production structure  

SciTech Connect

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.

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

1982-02-09

275

Bundled pipe speeds offshore laying  

SciTech Connect

Technology which allows pipelines to be installed in bundles is expediting pipelay operations in the North Sea. This paper reports how the piggyback system was recently used on 60 km of North Sea gas pipelines for three major projects. For 7 years the practice of installing two or more pipelines in one operation has become an established practice for North Sea offshore oil and gas projects. The technique, commonly referred to as a piggyback operation, reduces installation costs, improves operation reliability, and cuts maintenance time.

Brockbank, J. (Avon Industrial Polymers Ltd., Melksham, Wiltshire (GB))

1990-05-07

276

Domestic Options to Offshore Oil and Gas.  

ERIC Educational Resources Information Center

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

Kash, Don E.

1983-01-01

277

Domestic Options to Offshore Oil and Gas.  

ERIC Educational Resources Information Center

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

Kash, Don E.

1983-01-01

278

Safety factor requirements for the offshore industry  

Microsoft Academic Search

The maintenance of structural integrity is a significant consideration in the safety management of offshore installations. Installations operating in the North Sea are primarily of welded construction and are subjected to severe environmental conditions, which induce significant fatigue loads. Thus, offshore installations are designed to resist structural failure from fatigue and extreme loading as well as other failure mechanisms, e.g.,

A. Stacey; J. V. Sharp

2007-01-01

279

Offshore Outsourcing: Risks, Challenges, and Potential Solutions  

Microsoft Academic Search

While offshore outsourcing is associated with several benefits, these ventures also pose many risks. In this paper, through an in-depth review, we develop a type 1 analysis theory about the various risks involved in offshore outsourcing projects, the challenges faced by managers in these collaboration initiatives, and solutions that may aid in overcoming those challenges. This paper contributes to both

Tejaswini Herath; Rajiv Kishore

2009-01-01

280

Off-Shoring: How Big Is It.  

National Technical Information Service (NTIS)

Off-Shoring: How Big Is It, is the second of three Academy Panel reports providing a comprehensive review of services off-shoring. This report presents the results of the Panels research using publicly available industry-level data and confidential, firm-...

2006-01-01

281

Offshore investment funds: monsters in emerging markets?  

Microsoft Academic Search

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

Woochan Kim; Shang-Jin Wei

2002-01-01

282

Offshore information systems outsourcing: strategies and scenarios  

Microsoft Academic Search

This paper presents the findings of an ongoing research study into offshore information technology and systems outsourcing. Fieldwork was conducted in India and the United Kingdom to identify different strategies and scenarios. Based on the premise that offshore outsourcing poses greater risks than using suppliers from the home country, the research develops a risk assessment matrix comprising four scenarios: body

Naureen Khan; Wendy L. Currie; Vishanth Weerakkody

2003-01-01

283

New production ideas solve old problems offshore  

Microsoft Academic Search

Significant new developments that will play an important role in future production of offshore gas and oil were discussed or introduced at the 1973 Offshore Technology Conference recently held in Houston: (1) how SEAL is progressing with development of subsea completion systems; (2) how Amoco installed the first North Sea jackup production platform; (3) what is available in concrete platforms;

1973-01-01

284

Offshore oil and gas technology assessment  

Microsoft Academic Search

In recent years offshore drilling and production technology has evolved in response to the challenges of deep waters and Arctic conditions. In this paper we discuss the development of offshore drilling rigs, platforms, subsea completion systems, pipelines, and tanker loading facilities. We conclude that current technologies modified to meet site-specific requirements are capable of drilling and producing oil and gas

L. Otteman; R. Crooke; R. Shoemaker

1985-01-01

285

Seepage in Vietnam — onshore and offshore examples  

Microsoft Academic Search

Hydrocarbon seepages in Vietnam are generally linked to migration from Tertiary source rocks, and seeps are present both onshore and offshore.Residual oil can be observed at outcrop in breached traps within Tertiary sections and in exhumed ‘buried hill’ traps in pre-Tertiary rocks in the onshore Hanoi Basin. There is active oil seepage on the western margin of the offshore Phu

J. J. Traynor; Chris Sladen

1997-01-01

286

Federal offshore statistics: leasing - exploration - production - revenue  

Microsoft Academic Search

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

Essertier

1984-01-01

287

Marine fouling in offshore areas east of Hainan Island, northern South China Sea  

NASA Astrophysics Data System (ADS)

This paper reports on results of the investigation of marine biofouling on offshore structures east of Hainan Island in the northern South China Sea. Two buoy investigation stations were deployed in Qiongdong (W1, 68 n miles offshore) and southern Qiongdong (J2, 23 n miles offshore) waters, respectively. At both sites, water depths were more than 100 meters. Test panels on iron frames were placed at 1, 10, 25, 50 and 100 m below the seawater surface, and exposed for 8 months from October 1989 to June 1990. The results indicated that hydroids, gooseneck barnacles and oysters were the most important fouling species in these offshore areas. Acorn barnacles were mainly found at Station J2. The maximum fouling accumulations were observed in near surface waters. Substantial reduction of biomass and species diversity occurred with increasing depth and distance from shore. Sources of fouling organisms and influences of environmental factors on the species distributions are discussed in this paper.

Yan, Tao; Yan, Wen-Xia; Dong, Yu; Wang, Hua-Jie; Yan, Yan; Liang, Guan-He

1999-09-01

288

Pacific offshore record of plinian arc volcanism in Central America: 1. Along-arc correlations  

NASA Astrophysics Data System (ADS)

We collected 56 marine gravity cores from the Pacific seafloor offshore Central America which contain a total of 213 volcanic ash beds. Ash-layer correlations between cores and with their parental tephras on land use stratigraphic, lithologic, and compositional criteria. In particular, we make use of our newly built database of bulk-rock, mineral, and glass major and trace element compositions of plinian and similarly widespread tephras erupted since the Pleistocene along the Central American Volcanic Arc. We thus identify the distal ashes of 11 Nicaraguan, 8 El Salvadorian, 6 Guatemalan, and 1 Costa Rican eruptions. Relatively uniform pelagic sedimentation rates allow us to determine ages of 10 previously undated tephras by their relative position between ash layers of known age. Linking the marine and terrestrial records yields a tephrostratigraphic framework for the Central American volcanic arc from Costa Rica to Guatemala. This is a useful tool and prerequisite to understand the evolution of volcanism at a whole-arc scale.

Kutterolf, S.; Freundt, A.; PeréZ, W.; MöRz, T.; Schacht, U.; Wehrmann, H.; Schmincke, H.-U.

2008-02-01

289

Applying high-resolution sequence stratigraphic tools to the Texas continental margin to fine-tune conventional sequence stratigraphic models and improve reservoir prediction  

SciTech Connect

A regional sequence stratigraphic study of the Texas continental margin resulted in an improved understanding of Pleistocene-Holocene eustatic sea level fluctuations and their influence on depositional environments associated with several distinct systems: the Colorado/Brazos system, the Texas interfluve region, and the Rio Grande system. The dataset consists of approximately 7500 kilometers of high-resolution seismic profiloes, 200 borehole descriptions, and 12 sediment cores. The study involved analysis of three independent variables to better constrain Pleistocene-Holocene sea level history: coastal onlap derived from high-resolution seismic profiles; oxygen isotope data determined from selected sediment cores; and paleoenvironmental data developed from high-resolution micropaleontologic analyses. Combined lithologic data and seismic facies analysis is used to map the distribution of major depositional systems on the shelf during one complete glacial eustatic cycle. Our study provided anopportunity to fine tune conventional stratigraphic models with regard to the distribution of potential reservoirs relative to regionally mappable stratigraphic surfaces.

Anderson, J.A.; Banfield, L.A.; Eckles, B.J. (Rice Univ., Houston, TX (United States)) (and others)

1996-01-01

290

Offshore propagation of coastal precipitation  

NASA Astrophysics Data System (ADS)

This work focuses on the seaward propagation of coastal precipitation with or without mountainous terrain nearby. Offshore of India, diurnal propagation of precipitation is observed in the Bay of Bengal. On the eastern side of the Bay a diurnal but non-propagating signal is observed near the west coast of Burma. This asymmetry suggests that the propagating mechanism is inertio-gravity waves. Perturbations generated by the diurnal heating over the coastal mountains of India propagate offshore, amplify in the upwind direction and dissipate in the downwind direction owing to critical level consideration. A linear model is applied to study these gravity waves. Analytical analysis is performed for various heating depths, mountain widths, stability, Coriolis effect, background mean wind, and friction. We assess how these affect the amplitude, dissipation, initiation phase, and propagation speed of the diurnal disturbance. The propagation of precipitation triggered by land/sea breeze, are distinguishable from a mountain-plain circulation. For mountain breeze, convection from mountain heating starts earlier; propagates slower; and damps faster than that of the land breeze. For mountains near the coast, the slower propagation and stronger earlier convection are due to the combination of two dynamical mechanisms. The propagation of precipitation is initially triggered by mountain breeze near the coastal mountain. Over the open ocean, the dominant signal propagates as that of the land breeze but with stronger convection.

Li, Yanping; Carbone, Rit

2013-04-01

291

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

SciTech Connect

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.

Coughlin, R.M.; Bement, W.O.; Maloney, W.V. (Pecten International Company, Houston, TX (United States))

1993-09-01

292

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

NASA Astrophysics Data System (ADS)

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

Nishimura, Sou; Ando, Masataka; Tadokoro, Keiichi

2005-08-01

293

Louisiana continental slope: geologic and seismic stratigraphic framework  

SciTech Connect

The continental slope of Louisiana from Green Canyon to Mississippi Canyon was studied by interpreting seismic CDP data and wells in the area. The slope is characterized by blocked canyon intraslope basins of various dimensions with maximum thickness of sediments in excess of 21,000 ft, rotational slump blocks and large-scale submarine slides. In the subsurface, the outer shelf and upper slope show contrasting character with that of the lower slope, especially below the Sigsbee Scarp. The seismic stratigraphic units established for the deep sea area can be recognized in their entirety up to a water depth of 6000 to 5500 ft. In shallower water salt tectonics obliterates the sequence. Fragmental records of the sequence, especially the top of Challenger boundary, have been recognized in as shallow as 2000 to 3000 ft of water. The Tertiary units often downlap and onlap directly on the Challenger unit, indicating the progradational nature of the clastic slope. The Sigsbee unit has been traced through the entire slope area and can be divided into five subunits of unique acoustical characteristics. The slope constantly regrades in response to Neogene sea level fluctuations. Loading of the shelf by deltaic deposition contributes to salt sill formation and flowage of salt over deep-water sediments on the slope during high sea level. Regressive sea is represented by slope failure, formation of large-scale submarine slides, filling of blocked canyon intraslope basins which show similar seismic facies to that of Orca and Pigmy basins as reported from DSDP studies, and sporadic uplifting of salt diapirs and massifs and the formation of linear transverse salt ridges.

Ray, P.K.; Cooke, D.W.

1987-05-01

294

Tephrochronology offshore Ischia Island, Tyrrhenian sea, Italy  

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

295

Meso-Cenozoic geodynamic evolution of the Paris Basin: 3D stratigraphic constraints  

Microsoft Academic Search

3D stratigraphic geometries of the intracratonic Meso-Cenozoic Paris Basin were obtained by sequence stratigraphic correlations of around 1 100 wells (well-logs). The basin records the major tectonic events of the western part of the Eurasian Plate, i.e. opening and closure of the Tethys and opening of the Atlantic. From earlier Triassic to Late Jurassic, the Paris Basin was a broad

François Guillocheau; Cécile Robin; Pascal Allemand; Sylvie Bourquin; Nicolas Brault; Gilles Dromart; Roselyne Friedenberg; Jean-Pierre Garcia; Jean-Michel Gaulier; Fabrice Gaumet; Bernard Grosdoy; Franck Hanot; Paul Le Strat; Monique Mettraux; Thierry Nalpas; Christophe Prijac; Christophe Rigollet; Olivier Serrano; Gilles Grandjean

2000-01-01

296

A simple application of stereographic projection in the measurement of stratigraphic thickness  

NASA Astrophysics Data System (ADS)

A simple method for calculating the true stratigraphic thickness of beds measured indirectly using tape and compass along sloping transects oblique to the bedding strike is described. This method minimizes the need for complex trigonometric formulae that otherwise need to be adapted to different arrangements of bedding dip direction and traverse slope direction. The method is equally useful in calculating the true thickness of stratigraphic units penetrated in boreholes, and data collected from road cuttings oblique to the strike of beds.

Fowler, Abdel-Rahman; Hashem, Waheed

2013-09-01

297

Offshore drilling, construction: Fortunes tied to stable gas prices  

Microsoft Academic Search

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

S. S. Pagano; T. Marsh

1993-01-01

298

An Economic Evaluation Method of Offshore Drilling Platform Overhaul Projects  

Microsoft Academic Search

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

Luo Dong-kun; Dai You-jin

2009-01-01

299

Corrosion prevention for offshore platforms  

SciTech Connect

Offshore oil and gas platforms are subjected to hostile, corrosive, marine environments and require continuous preventive maintenance to ensure prolonged and safe operation. Corrosion is identified as it occurs: above water, in the splash zone, and subsea. Coating systems, surface preparation, application, and maintenance are discussed for abovewater corrosion prevention. The advantages and limitations of added metal for corrosion allowance, corrosion-resistant cladding, and coatings are discussed for splash-zone corrosion prevention. Major emphasis is on the use of cathodic protection (CP) to prevent subsea corrosion. Included in the discussion are the advantages and limitations of sacrificial-anode and impressed-current CP systems for use with steel and reinforced concrete structures. Subsea monitoring and the effects of platform CP on well casings are also discussed.

Schremp, F.W.

1984-04-01

300

Cost control for offshore structures  

SciTech Connect

Design overruns and late delivery of material and equipment are frequently the main causes of delays and cost increases in engineering projects. The impact on cost and time is likely to be particularly critical in the case of offshore projects which are affected by narrow weather windows. The structures may comprise varying types of platforms to be used as centers for drilling, production, living quarters, storage, mooring and loading, also sub-sea completions of wellheads and pipelines. Starting construction work on time is of prime importance for the success of the project. However, venturing into the construction phase without proper appraisal and definition of the work scope, and on the basis of a guarantee of cost reimbursement, has frequently proved to be the road to disaster.

Lo Cascio, E.

1981-12-01

301

Offshore medicine: Medical care of employees in the offshore oil industry  

SciTech Connect

This book is specifically designed to help the doctor who has to provide medical care for the expanding offshore oil industry. It describes the pattern of work offshore and the medical problems which it generates. The special features of offshore medical care are described along with the training of medics, the design of hospital facilities, and the provision of back-up services to cope with them. These are special chapters on diving, hygiene, and catering, dentistry, and legal aspects.

Cox, R.A.F.

1987-01-01

302

Stratigraphic development of Ship Shoal, northern Gulf of Mexico  

SciTech Connect

Ship Shoal is the easternmost member of a Holocene inner-shelf shoal group located 25 km offshore of the Mississippi River delta plain in south-central Louisiana. Ship Shoal is a shore-parallel sand body 50 km long and 8-12 km wide, lying in 10 m of water with a relief above the surrounding shelf of 3 m to 7 m east to west along its crest axis. A comparison of hydrographic surveys indicate that the shoal has migrated 2 km landward since 1850. High resolution seismic profiles document Ship Shoal is an isolated sand body which punches out seaward on the erosional inner shelf and terminates landward on a depositional surface. Vibracores document Ship Shoal is 305 m thick sand body composed of shoal crest, lower shoal, back shoal, and lagoonal deposits lying disconformably over regressive deposits of the Maringouin delta complex, transgressed 6000 years B.P. The stratigraphy of Ship Shoal indicate it originated during the transgression of a Holocene barrier shoreline associated with the Maringouin delta complex. The presence of reworked clasts of beach rock Crassostrea sp. shell, and Rangia sp. shell within the sand body and overlying in-situ lagoonal deposits, document the former existence of a barrier shoreline. The transgressive shoal sequence shows that Ship Shoal has migrated to its present position from a more seaward location and the shoal and body contained no in-situ barrier shoreline deposits. The development of Ship Shoal illustrates a process whereby transgressive barrier shorelines are transformed into reworked barrier sand bodies lying on the inner shelf during relative sea level rise.

Penland, S.; Suter, J.R.; Moslow, T.F.

1985-01-01

303

Studies on structural monitoring of offshore jacket platforms  

NASA Astrophysics Data System (ADS)

The paper describes a series of analytical and physical model studies conducted to develop an online monitoring system for offshore platforms. An actual offshore jacket platform situated in a water depth of 88m was selected for the study. A detailed 3D finite element analysis of the platform involving free and forced vibration revealed that there were dynamic characteristics of the platform which could be used to identify the structural damages in the structure. Having established the feasibility of the method, further work was carried out on a physical model of the platform. Dynamic characteristics of the model were determined by spectral analysis of the response data, simulating various changes including compete and partial damages on individuals elements of the model. Simultaneously work was also initiated to apply the result of the physical model tests for interpreting the causes of the changes in the dynamic characteristics using ANN trained with the database created through experiments and analysis. The final outcome of these comprehensive studies was a scheme for integrity monitoring of jacket type of fixed offshore platforms using vibration characteristics of the structure.

Idichandy, V. G.; Mangal, Lalu

2001-06-01

304

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

SciTech Connect

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

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

1986-05-01

305

Radiocarbon analyses from Cincinnati, Ohio, and their implications for glacial stratigraphic interpretations  

USGS Publications Warehouse

Detailed analysis of a site near Cincinnati, Ohio, shows that 14C ages of samples in a single geologic unit can have a range of several thousand years and ages from different stratigraphic units can overlap. At the Sharonville site, four 14C samples from organic silt below glaciogenic deposits have an inverted chronologic sequence, suggesting contamination, but nevertheless they indicate the silt was deposited before 27,000 yr B.P. A stump cluster in growth position, wood fragments, and moss from the upper surface of the silt may differ by as much as 2300 14C yr. Five ages from the stump cluster constrain the timing of a glacier advance of the Laurentide ice sheet to its southern limit in the Cincinnati area at 19,670 ?? 68 yr B.P. Overlying glaciogenic sediments contain transported wood that may be as much as 3200 yr older than the advance. This range of ages points out that, for a given site, several age measurements are required to determine when a glacier advance occurred. Because the measured ages in this study span the entire interval suggested for a twofold sequence of advance, retreat, and readvance of the margin of the Miami sublobe, we suggest a single advance to its terminal position in the Cincinnati area as an alternate hypothesis for testing. ?? 1990.

Lowell, T. V.; Savage, K. M.; Scott, Brockman, C.; Stuckenrath, R.

1990-01-01

306

Stochastic Analysis of Offshore Tower Structures.  

National Technical Information Service (NTIS)

A general theory is developed for evaluating the response of offshore structures in deep water subjected to random wave forces or earthquakes. The analytical approach to this stochastic, fluid elasticity problem takes into account the non-linearities aris...

A. K. Malhotra J. Penzien

1969-01-01

307

Nonlinear Seismic Response of Articulated Offshore Tower.  

National Technical Information Service (NTIS)

The seismic response of articulated offshore tower has been investigated by the spectral analysis method which is based on the principle of random vibration, where seismic excitation is assumed to be a broadband stationary process. The nonlinear dynamic e...

N. Islam S. Ahmad

2002-01-01

308

Ultimate Strength Analysis of Framed Offshore Structures.  

National Technical Information Service (NTIS)

An efficient method is presented for analysis of the non-linear behavior of offshore structures up to ultimate strength. The algorithm is based on the idealizied structural unit method. Geometrical and material nonlinearities are accounted for by applying...

J. E. van Aanhold

1985-01-01

309

31 CFR 544.406 - Offshore transactions.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

310

31 CFR 541.406 - Offshore transactions.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

311

Off-Shoring: What Are Its Effects.  

National Technical Information Service (NTIS)

Shifting business operations to off-shore locations and its impact on Americas workforce and economy are central features in the policy debate over globalization. Especially important is the impact on the nations high technologyservicesindustries, especia...

2007-01-01

312

Engineering Challenges for Floating Offshore Wind Turbines  

SciTech Connect

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.

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

2007-09-01

313

31 CFR 548.406 - Offshore transactions.  

Code of Federal Regulations, 2010 CFR

... Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY BELARUS SANCTIONS REGULATIONS Interpretations § 548.406 Offshore transactions. The prohibitions in § 548.201 on...

2010-07-01

314

EMS offshore. A new horizon for paramedics.  

PubMed

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

Mallard, A S

1991-10-01

315

31 CFR 595.407 - Offshore transactions.  

Code of Federal Regulations, 2013 CFR

... Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY TERRORISM SANCTIONS REGULATIONS Interpretations § 595.407 Offshore transactions. The prohibitions contained in §...

2013-07-01

316

31 CFR 546.406 - Offshore transactions.  

Code of Federal Regulations, 2013 CFR

... Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY DARFUR SANCTIONS REGULATIONS Interpretations § 546.406 Offshore transactions. The prohibitions in § 546.201 on...

2013-07-01

317

Reservoir development in Miocene carbonates, Central Luconia Province, offshore Sarawak  

SciTech Connect

The broad platform of the central Luconia province of offshore Sarawak is characterized by extensive development of Miocene carbonates. Their distribution was controlled by paleostructures that formed earlier during Oligocene-middle Miocene faulting. Platform-type buildings formed on fault-bounded regional highs, whereas pinnacle types formed in basinal areas. Relief of the pinnacles was controlled by fault reactivation of the structures during deposition, and some buildups in structurally stable areas ceased to develop because they could not keep pace with rising sea levels. Seismic, well-log, and rock data of several buildups from different stratigraphic levels (Cycles III-VI) were integrated in formulating a model for reservoir development in the Luconia carbonates. Depositional and diagenetic cycles due to eustatic sea level changes exerted strong influence on the internal architecture of the buildups. Cycling depositional patterns, represented by alternating layers with good and poor porosities, include small-scale units (<3 m thick) recognized in cores and reservoir-scale successions (>63 m thick) identifiable in well logs and seismic data. Cycle V carbonates, for instance, consist of three Tortonian-Messinian depositional sequences. Two layers of dolomite formed in all buildups, each contemporaneous with a period of emergence. The Messinian diagenetic cycle, related to the 5.5 Ma sea level lowstand, partially overprinted the Tortonian diagenetic cycle that occurred during the 6.3 Ma lowstand. Superposition of these diagenetic cycles, with leaching, chalkification, and dolomitization, is responsible for a complex pore geometry in the carbonate reservoirs. This model can be applied to map the reservoir units in the carbonate buildups within the entire basin.

Ali, M.Y. (Petronas Research and Scientific Services, Kuala Lumpur (Malaysia))

1994-07-01

318

Neogene sequence stratigraphy, Nam Con Son Basin, offshore Vietnam  

SciTech Connect

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

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

1996-01-01

319

Application of the boundary-element method to offshore cathodic protection modeling  

Microsoft Academic Search

This paper deals with the main aspects of the calculation of current and potential distributions and summarizes some results obtained on different systems using a computer program based on the boundary-element method. Model results are compared to literature data for well-known geometries, and to experimental data obtained both in laboratory testing with a suitable cell and infield testing on offshore

P. Cicognani; F. Gasparoni; B. Mazza; T. Pastore

1990-01-01

320

Proceedings of the 6th international offshore mechanics and Arctic engineering symposium, Vol. 2  

Microsoft Academic Search

This book presents the papers given at a conference on offshore platforms. Topics considered at the conference included hydrodynamics, wave forces, flow-induced vibrations, oscillating flow, wave propagation, damping, the nonlinear dynamic behavior of moored platforms, elasticity, marine risers, drill pipes, ultrasonic testing, and eddy current testing.

J. S. Chung; S. Berg; S. K. Chakrabarti; S. R. Montgomery

1987-01-01

321

Arctic offshore drilling: a new challenge  

SciTech Connect

The arctic offshore environment provides the drilling industry with its greatest challenge yet. Problems due to sea ice, high wind, extreme cold and poor bottom soil have required the design of special structures appropriate only for arctic offshore drilling. The challenge lies not just in the obvious factors of temperature and ice, but also the basic physics of ice problems are not well understood. The arctic environment and the petroleum industry are discussed.

Wetmore, S.B.

1985-11-01

322

Decommissioning of Offshore Oil and Gas Installations  

Microsoft Academic Search

The offshore oil and gas industry had its beginnings in the Gulf of Mexico in 1947. The first offshore development used a\\u000a multipiled steel jacket to support the topside production facilities, a design which has since been used extensively. Now\\u000a there are more than 7000 drilling and production platforms located on the Continental Shelves of 53 countries [1]. Some of

M. D. Day

323

Corrosion control survey methods for offshore pipelines  

SciTech Connect

Construction, operation, and maintenance of offshore pipelines and other facilities are expensive. The consequences of an offshore corrosion failure can be devastating. For these reasons, cathodic protection (CP) has become a universally applied technique for mitigating corrosion. Marine pipelines are typically provided with CP by bracelet anodes of zinc or aluminum. Impressed current systems at platforms or onshore are also used as well as hybrid systems that use a combination of the two. In this paper survey techniques are described and evaluated.

Weldon, C.P.; Kroon, D. (Corrpro Co. Inc., North, Spring, TX (US))

1992-02-01

324

Arctic and offshore research: Technology status report  

SciTech Connect

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.

Not Available

1987-01-01

325

Arctic and offshore research. Technology status report  

SciTech Connect

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.

Not Available

1985-10-01

326

The modified gap excess ratio (GER*) and the stratigraphic congruence of dinosaur phylogenies.  

PubMed

Palaeontologists routinely map their cladograms onto what is known of the fossil record. Where sister taxa first appear as fossils at different times, a ghost range is inferred to bridge the gap between these dates. Some measure of the total extent of ghost ranges across the tree underlies several indices of cladistic/stratigraphic congruence. We investigate this congruence for 19 independent, published cladograms of major dinosaur groups and report exceptional agreement between the phylogenetic and stratigraphic patterns, evidenced by sums of ghost ranges near the theoretical minima. This implies that both phylogenetic and stratigraphic data reflect faithfully the evolutionary history of dinosaurs, at least for the taxa included in this study. We formally propose modifications to an existing index of congruence (the gap excess ratio; GER), designed to remove a bias in the range of values possible with trees of different shapes. We also propose a more informative index of congruence--GER*--that takes account of the underlying distribution of sums of ghost ranges possible when permuting stratigraphic range data across the tree. Finally, we incorporate data on the range of possible first occurrence dates into our estimates of congruence, extending a procedure originally implemented with the modified Manhattan stratigraphic measure and GER to our new indices. Most dinosaur data sets maintain extremely high congruence despite such modifications. PMID:19085331

Wills, Matthew A; Barrett, Paul M; Heathcote, Julia F

2008-12-01

327

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

Microsoft Academic Search

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

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

2006-01-01

328

Concerted Action for Offshore Wind Energy Deployment (COD): Grid Integration of Offshore Wind Farms  

Microsoft Academic Search

The objective of the European Concerted Action on Offshore Wind Energy Deployment (COD) is to speed up the responsible deployment of offshore wind energy in the EU by early identification and possibly to remove not explicitly technical barriers: legal, administrative, policy, environmental and grid infrastructure planning issues. The COD is carried out by eight sea- bordering member states, represented by

Achim Woyte; Helen Snodin; Paul Gardner; Ruud de Bruijne

329

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

Microsoft Academic Search

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

J. Jonkman; W. Musial

2010-01-01

330

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

NASA Astrophysics Data System (ADS)

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

Hu, J.; Lokier, S. W.

2012-04-01

331

Method for servicing offshore well  

SciTech Connect

This patent describes a method of servicing a cased offshore well having a subsea blowout preventer stack and a riser extending from said stack to an above-water work area, said blowout preventer stack including sealing rams. It comprises: running a sealing nipple, which is open at its lower end and closed at its upper end except for a wireline packing means and which has a wireline extending through said wireline packing means, from said work area down through said riser into said blowout preventer stack to a position adjacent said sealing rams. The wireline being attached to a cement bond logging tool extending below said sealing nipple; closing said sealing rams about said sealing nipple and pressurizing said well below said blowout preventer stack to a level sufficient to eliminate any microannulus between the casing of said well and cement surrounding said casing by application of fluid pressure to said well from a pressure line extending from said work area; operating said cement bond logging tool in said well; opening said sealing rams; and removing said sealing nipple and cement bond logging tool from said blowout preventer stack and riser.

Sauer, C.W.; Stockinger, M.P.; Moran, L.K.

1990-03-06

332

Polyamine sensitization in offshore workers handling drilling muds.  

PubMed

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

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

1989-11-01

333

CABFAC/USGS, a FORTRAN program for Q-mode factor analysis of stratigraphically ordered samples  

USGS Publications Warehouse

This program is a revision of the CABFAC program of Kovan and Imbrie (1971) which incorporates the following improvements: each factor is plotted against depth on the printer; samples are ordered stratigraphically by the program, so that input data need not be ordered stratigraphically; an option has been added to transform all variables to zero means before calculating the cosine-theta matrix; and all subroutines are variable-dimensioned, so that the size of .the program may be changed by simply altering the main program.

Adams, David P.

1976-01-01

334

Offshore oil gas trends in ROVs tooling  

SciTech Connect

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

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

1994-04-01

335

47 CFR 22.1037 - Application requirements for offshore stations.  

Code of Federal Regulations, 2012 CFR

...requirements for offshore stations. 22.1037 Section...Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED...requirements for offshore stations. Applications for...would be caused to any base or mobile station using the...

2012-10-01

336

78 FR 18618 - National Offshore Safety Advisory Committee; Vacancies  

Federal Register 2010, 2011, 2012, 2013

...the exploration of offshore mineral and energy resources insofar as they relate to matters...the exploration of offshore mineral and energy resources insofar as they relate to...national origin, political affiliation, sexual orientation, gender identity,...

2013-03-27

337

Offshoring of Services: An Overview of the Issues.  

National Technical Information Service (NTIS)

Much attention has focused on the 'offshoring' of services to lower-wage locations abroad. Offshoring generally refers to an organization's purchase of goods or services from abroad that were previously produced domestically. Extensive public debate has a...

2005-01-01

338

The proceedings of the fourth (1994) international offshore and polar engineering conference. Volume 4  

SciTech Connect

This conference proceedings is one volume of a four volume set dealing with oil and gas industry operations in polar and offshore environments. This particular conference deals primarily with materials and designs for offshore platforms and tanker ships. It provides papers dealing with concretes, steels, and composite materials and the IR mechanical properties. Many papers review testing and processes for welded joints. It also provides papers which deal with fracture mechanics and corrosion protection. Approximately 74 papers have been individually abstracted and entered into the data base.

Ueda, Yukio; Tomita, Yasumitsu [eds.] [Osaka Univ. (Japan); Dos Santos, J.F. [ed.] [GKSS Forschungszentrum Geesthacht (Germany); Langen, I. [ed.] [Statoil, Stavanger (Norway); Waagaard, K. [ed.] [Veritec, Hovik (Norway)

1994-12-31

339

Federal offshore statistics: leasing - exploration - production - revenue  

SciTech Connect

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.

Essertier, E.P. (comp.)

1984-01-01

340

Offshore '76: semi-submersible oil storage: initial design looks good. [1-million-barrel capacity  

Microsoft Academic Search

A 1\\/60 scale model of a proposed 1-million-barrel semi-submersible crude storage and production platform unit with unique stabilizing features was extensively tested. Patented design is applicable to many offshore areas where fixed storage vessels are not economically feasible.

Biewer

1976-01-01

341

Verification of cryogenic blowout control technology for offshore wells. Final report  

Microsoft Academic Search

This report describes the BDM laboratory test program which successfully demonstrated the functional principle of a cryogenic blowout control device for offshore oil wells. The device, which would first be placed downhole as part of the casing string while drilling and later be part of the production tubing, is referred to as a Downhole Shut-In Device (DSD). This report is

J. V. Powers; W. E. Kuchar; B. McClure; W. E. Schwinkendorf; J. Gregory

1982-01-01

342

British Neutrality versus Offshore Balancing in the American Civil War: The English School Strikes Back  

Microsoft Academic Search

The American Civil War is an important test case for offensive realism because it was the last occasion when offshore balancing by Britain could have prevented the United States from becoming a regional hegemon. Instead, Britain drew on the norm of nonintervention to justify a policy of neutrality. Offensive realists reject the idea that Britain was constrained by normative considerations

Richard Little

2007-01-01

343

Processing Bachaquero and offshore California crudes  

SciTech Connect

The need to refine heavy crudes such as Venezuela's Bachaquero and California's offshore crude oils has encouraged several refiners to revamp existing facilities and to add new residual oil processing capabilities. This paper addresses some of the design and operating factors to be considered when processing these types of crudes. It also presents a summary of licensor data for upgrading vacuum residue from Bachaquero crude. Additionally, the paper describes some of the projects designed for processing Bachaquero crude and how similar processing can apply to some of the offshore California crudes which are similar to Bachaquero.

Jones, W.T.; Meers, S.W.; McClanahan, D.E.; Mitchem, C.

1986-01-01

344

The Stability of Offshore Outsourcing Relationships  

Microsoft Academic Search

• \\u000a \\u000a \\u000a Offshore outsourcing of administrative and technical services has become a mainstream business practice. Increasing commoditization\\u000a of business services and growing client experience with outsourcing have created a range of competitive service delivery options\\u000a for client firms.\\u000a \\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a Yet, data from the Offshoring Research Network (ORN) suggests that, despite increasing market options and growing client expectations\\u000a related to service quality

Stephan Manning; Arie Y. Lewin; Marc Schuerch

2011-01-01

345

Offshore structure incorporating a conductor deflecting system  

SciTech Connect

An offshore structure that is supported above the water's surface by at least one substantially vertically disposed leg which extends to the ocean floor. The structure is adapted to accommodate a vertical member or riser conductor having a deflector segment capable of engaging one or more fluid carrying conduits or risers which are lowered therethrough. The deflector segment is positioned to engage a lowering riser end so that the riser will be urged outwardly and away from the base of the structure. The riser or risers can thus be readily connected to subsea pipelines which terminate adjacent to the foot of the offshore structure.

Mott, G. E.

1985-05-28

346

An overview of offshore wind electric energy resources  

Microsoft Academic Search

In this paper we review offshore wind energy for generating electricity at off-shore sites. In particular, we survey the impacts of offshore wind integration into the grid, various types of generators and their dynamic modeling, fault ride-through techniques used to improve generator and grid integration performance, the aggregated wind turbines modeling and finally highlight some stability and control issues.

Hamed H. Aly; M. E. El-Hawary

2010-01-01

347

Fouling of Offshore Structures in China-a Review  

Microsoft Academic Search

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

Tao Yan; Wen Xia Yan

2003-01-01

348

Offshore wind resource estimation using wave buoy data  

Microsoft Academic Search

In the coming decade installed offshore wind capacity is expected to expand rapidly. This will be both technically and economically challenging. Precise wind resource assessment is one of the more imminent challenges. It is more difficult to assess wind power offshore than onshore due to the paucity of representative wind speed data. Offshore site-specific data is less accessible and is

Aoife M. Foley; Cathal Kerlin; Paul G. Leahy

2012-01-01

349

Successful Method of Fracturing in Offshore Oil Fields in China  

Microsoft Academic Search

Fracturing technology has been applied very rarely in offshore oil fields in China. Compared with on land, fracturing in offshore oil fields has its own features. Firstly, the cost of operation and fracturing treatment is higher, so a higher ratio of success and effect is required. Secondly, deviated wells and horizontal wells, which are common in offshore oil fields, increase

Q. Meng; S. Zhang; X. Huang; B. Chen; S. Tian

2010-01-01

350

International Offshore Students' Perceptions of Virtual Office Hours  

ERIC Educational Resources Information Center

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…

Wdowik, Steven; Michael, Kathy

2013-01-01

351

Are offshore power plants realistic. [Alternative to nuclear power plants  

Microsoft Academic Search

Offshore fossil-fueled electric power plants offer a positive alternative to nuclear proliferation, a viable technology for providing electricity to coastal cities. Such plants combine new technology from the offshore oil industry with efficient power generation techniques, are cheaper than nuclear plants, and could burn coal or solid waste or a mixture of both. Offshore power plants could utilize ocean water

Adler

1976-01-01

352

Offshore wind energy systems for the U.K  

Microsoft Academic Search

Some of the more important factors affecting the design of offshore wind energy systems are discussed. It is shown that power densities in offshore winds are attractively high, of the order of 300 kW\\/linear meter (perpendicular to the wind direction). The economics of offshore operation strongly favors the use of large wind turbines (about 100 m diameter) and a low

P. J. Musgrove

1979-01-01

353

POWER - A METHODOLOGY FOR PREDICTING OFFSHORE WIND ENERGY RESOURCES  

Microsoft Academic Search

An accurate estimate of the long-term wind speed is essential to site an offshore wind farm effectively. Unfortunately measured wind speed data at potential offshore wind farm sites are currently sparse. A major European Commission funded project called 'Predicting Offshore Wind Energy Resources\\

G M Watson; J A Halliday; J P Palutikof; T Holt; R J Barthelmie; J P Coelingh; L Folkerts; G F M Wiegerinck; E J van Zuylen; J W Cleijne; G C S Hommel

354

Share Restrictions, Liquidity Premium and Offshore Hedge Funds  

Microsoft Academic Search

This paper examines liquidity premium focusing on the difference between offshore and onshore hedge funds. Due to tax provisions and regulatory concerns, offshore and onshore hedge funds have different legal structures, which lead to differences in share restrictions such as a lockup provision. We find that offshore investors collect higher illiquidity premium when their investment has the same level of

Bing Liang

355

Development Potential for California's Offshore Wind Energy Resource  

Microsoft Academic Search

An initial analysis was performed for areas suitable for offshore wind farm development near the California coast. The siting of an offshore wind farm is limited by water depth, with shallow water being the most preferable economically. Acceptable depths for offshore wind farms were broken up into three categories, based on current and future wind turbine tower support technology; <=20

M. J. Dvorak; M. Z. Jacobson; C. L. Archer

2007-01-01

356

76 FR 70350 - West Oahu Offshore Security Zone  

Federal Register 2010, 2011, 2012, 2013

...The West Oahu Offshore Zone does not include...aircraft and support personnel, or other personnel...National Technology Transfer and Advancement...T14-1048 West Oahu Offshore Security Zone...The West Oahu Offshore Zone does not include...e) Enforcement personnel. The U.S....

2011-11-14

357

International Offshore Students' Perceptions of Virtual Office Hours  

ERIC Educational Resources Information Center

|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…

Wdowik, Steven; Michael, Kathy

2013-01-01

358

TRANSMISSION OPTIONS FOR OFFSHORE WIND FARMS IN THE UNITED STATES  

Microsoft Academic Search

While offshore wind farms have been installed in Europe for over a decade, developers in the United States are only beginning to look toward the offshore resource. This paper provides an introduction to transmission issues for offshore wind farms in North America, aimed towards non-electrical engineers in the windpower industry. Topics include cable terminology and installation, and factors involved in

Sally D. Wright; Anthony L. Rogers; James F. Manwell

359

Offshore Wind Farm Layout Optimization (OWFLO) Project: Preliminary Results  

Microsoft Academic Search

Optimizing the layout of an offshore wind farm presents a significant engineering challenge. Most of the optimization literature to date has focused on land-based wind farms, rather than on offshore farms. Typically, energy production is the metric by which a candidate layout is evaluated. The Offshore Wind Farm Layout Optimization (OWFLO) project instead uses the levelized production cost as the

Christopher N. Elkinton; James F. Manwell; Jon G. McGowan

360

Technical and economic aspects of a floating offshore wind farm  

Microsoft Academic Search

Development of the conceptual design for FLOAT – an offshore floating wind turbine – is described in this paper. This design represents a marriage of the wind power and offshore oil and gas technology. The objective of the FLOAT project is to develop a floating wind turbine system enabling the economic generation of electricity from wind power in offshore locations,

K. C Tong

1998-01-01

361

OFFSHORE WIND FARM LAYOUT OPTIMIZATION (OWFLO) PROJECT: AN INTRODUCTION  

Microsoft Academic Search

Optimizing the layout of an offshore wind farm presents a significant engineering challenge. Most of the optimization literature to date has focused on land-based wind farms, rather than on offshore farms. The conventional method used to lay out a wind farm combines a turbine cost model and a wake model in conjunction with an optimization routine. In offshore environments, however,

C. N. Elkinton; J. F. Manwell; J. G. McGowan

362

Visual impact assessment of offshore wind farms and prior experience  

Microsoft Academic Search

Energy planners have shifted their attention towards offshore wind power generation and the decision is supported by the public in general, which in the literature has a positive attitude towards offshore wind generation. However, globally only a few offshore wind farms are operating. As more wind farms start operating and more people become experienced with especially the visual impacts from

Jacob Ladenburg

2009-01-01

363

A fuzzy approach to the lectotype optimization of offshore platforms  

Microsoft Academic Search

Lectotype optimization of offshore platforms is of particular importance in the concept design process. Lectotype optimization involves multiple objectives with uncertainty and so is a problem of multiple attribute decision making. To date, there have been few published works on this topic in the context of offshore engineering. This paper develops a framework and methodology for evaluation of offshore platform

S. Chen; G. Fu

2003-01-01

364

Boundary Spanning in Offshored Information Systems Development Projects  

ERIC Educational Resources Information Center

|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…

Krishnan, Poornima

2010-01-01

365

Boundary Spanning in Offshored Information Systems Development Projects  

ERIC Educational Resources Information Center

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…

Krishnan, Poornima

2010-01-01

366

TAX AVOIDANCE FOR RESIDENT BUSINESS BY ESTABLISHING OFFSHORE COMPANIES  

Microsoft Academic Search

Until nowadays, a wide spectrum of offshore services satisfying various business needs has been developed. The offshore industry has turned into a global business, and reached all corners of the world, covering about a half of the world’s financial transactions. The offshore companies are a solution for everyone who is planning new activity and are interested in business development and

Marilena CIOBANASU; Iustin PRIESCU; Anca Mirela POSTOLE; Elena Mihaela ILIESCU

367

Use of coatings to supplement cathodic protection of offshore structures  

Microsoft Academic Search

Field experience has demonstrated the synergism between cathodic protection and organic coatings for providing long term corrosion protection to submerged offshore structures. This concept of coated steel with cathodic protection (CP) has been used by offshore oil producers to achieve weight and cost savings on offshore structures. For structures in deepwater, the weight savings are significant. Also, in areas where

W. H. Thomason; S. E. Pape; S. Evans

1987-01-01

368

Preliminary stratigraphic and structural architecture of Bhutan: Implications for the along strike architecture of the Himalayan system  

Microsoft Academic Search

Preliminary mapping and stratigraphic correlation of Lesser Himalayan rock in eastern Bhutan using field characteristics, U–Pb detrital zircon dating, and ?Nd geochemistry define the first-order stratigraphic architecture of the Indian passive margin sequence in the eastern Himalaya. We use this new image of the lateral and vertical relationships of the original stratigraphy to determine the structural framework of the eastern

Nadine McQuarrie; Delores Robinson; Sean Long; Tobgay Tobgay; Djordje Grujic; George Gehrels; Mihai Ducea

2008-01-01

369

1984\\/84. Geological maps and summary of the Cambrian stratigraphic units and relationships in the Henty River - Williamsford area  

Microsoft Academic Search

Geological mapping has clarified some important stratigraphic relationships within the Mt Read Volcanics and adjacent sedimentary sequences in the Basin Lake - Howards Road - Williamsford area. There is a marked stratigraphic mis-match across the Henty Fault system, and the wedge of flysch sediments together with andesitic-basaltic volcanic rocks and ultramafic rocks between the North and South Henty Faults does

K. D. Corbett

1984-01-01

370

Congruence between Phylogenetic and Stratigraphic Data on the History of Life  

Microsoft Academic Search

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

Michael J. Benton; Rebecca Hitchin

1997-01-01

371

Tectono-stratigraphic terranes and detachment faulting of the South China Sea and Sulu Sea  

Microsoft Academic Search

Geoscientific data acquired from the South China Sea and Sulu Sea areas by BGR since 1977 are compiled and interpreted as comprehensive data sets, together with available information of commercial wells and drillsites of the Ocean Drilling Program (ODP). Generalized stratigraphy and lithology are discussed and correlated with the interpreted seismic profiles. On the basis of the stratigraphic and structural

H. U. Schlüter; K. Hinz; M. Block

1996-01-01

372

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

Microsoft Academic Search

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

Susan M. Kidwell

1989-01-01

373

Stratigraphic and sedimentological evidence for late Wisconsinan sub-glacial outburst floods to Laurentian Fan  

Microsoft Academic Search

Sub-glacial meltwater produces a distinctive stratigraphic and sedimentological response on the continental margin. Seismo-stratigraphy of Laurentian Channel reveals thick till deposits at its seaward end that pass laterally into stratified sediment in deeper basins, that may record periods of water build up beneath the ice. Two scales of meltwater discharge are recognised: large scale that caused catastrophic erosion and transported

David J. W. Piper; John Shaw; Kenneth I. Skene

2007-01-01

374

Sequence stratigraphic analysis of the Lower Permian Hueco Group, northern Sierra Diablo, west Texas  

Microsoft Academic Search

The upper Wolfcamp Hueco Group in the northern Sierra Diablo of west Texas was deposited in a shelf setting on the western margin of the Delaware basin. This outcrop study subdivides the Hueco Group, including the Powwow Formation, into a sequence stratigraphic framework. Two depositional sequences and component system tracts within the Hueco have been defined on the basis of

1992-01-01

375

Stratigraphic architecture of extensional basins: Insights from a numerical model of sedimentation in evolving half grabens  

Microsoft Academic Search

We present a numerical model for the tectonostratigraphic evolution of half grabens which duplicates many of the stratigraphic relationships observed in extensional terranes of the southwestern United States and elsewhere. The model also generates insights and predictions on the impact of fault geometry, rates of faulting, and rates of erosion and sediment transport on landscape evolution, stratal geometry, and facies

Christopher J. Travis; Jeffrey A. Nunn

1994-01-01

376

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

Microsoft Academic Search

Received 20 September 2006; revised 12 February 2007; accepted 17 May 2007; published 24 August 2007. (1) The geologic history of Crater Terby is developed through geomorphic and stratigraphic analyses within the regional context of the Hellas basin. Terby exhibits ? 2-km-thick sequences of layers that consist of repetitive, subhorizontal and laterally continuous beds. The layers are predominantly fine-grained as

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

2007-01-01

377

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

SciTech Connect

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

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

1980-04-01

378

Spectral stratigraphy: multispectral remote sensing as a stratigraphic tool, Wind River/Big Horn basin, Wyoming  

SciTech Connect

Stratigraphic and structural analyses of the Wind River and Big Horn basins areas of central Wyoming are in progress. One result has been the development of a new approach to stratigraphic and structural analysis that uses photogeologic and spectral interpretation of multispectral image data to remotely characterize the attitude, thickness, and lithology of strata. New multispectral systems that have only been available since 1982 are used with topographic data to map upper paleozoic and Mesozoic strata exposed on the southern margin of the Bighorn Mountains. Thematic Mapper (TM) satellite data together with topographic data are used to map lithologic contacts, measure dip and strike, and develop a stratigraphic column that is correlated with conventional surface and subsurface sections. Aircraft-acquired Airborne Imaging Spectrometer and Thermal Infrared Multispectral Scanner data add mineralogical information to the TM column, including the stratigraphic distribution of quartz, calcite, dolomite, montmorillonite, and gypsum. Results illustrate an approach that has general applicability in other geologic investigations that could benefit from remotely acquired information about areal variations in attitude, sequence, thickness, and lithology of strata exposed at the Earth's surface. Application of their methods elsewhere is limited primarily by availability of multispectral and topographic data and quality of bedrock exposures.

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

1987-05-01

379

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

Microsoft Academic Search

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

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

2003-01-01

380

Chapter 11 The role of fuzzy logic in sedimentology and stratigraphic models  

Microsoft Academic Search

There has been a recent explosive growth in the theory and application of fuzzy logic and other related 'soft' computing techniques, opening new ways of modeling based on knowledge expressed in natural language. Fuzzy logic systems (based on fuzzy set theory), produce realistic sedimentation dispersal patterns in sedimentologic simulations in general and stratigraphic models in particular. The purposes of this

Robert V. Demicco; George J. Klir; Radim Belohlavek

2003-01-01

381

Biostratigraphic calibration in sequence stratigraphic analysis: Pliocene-Pleistocene case study from Gulf of Mexico  

Microsoft Academic Search

Biostratigraphic analysis provides chronostratigraphic data for correlating depositional sequences and paleoecologic data helpful in identifying depositional facies. These data sets are essential for correct analysis of sequence stratigraphy in areas of complex depositional architecture and structural style. The most useful sequence stratigraphic element for correlation is the condensed section. The condensed section is a facies consisting of thin marine beds

W. W. Jr. Wornardt; J. M. Armentrout; J. L. Clement

1989-01-01

382

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

National Technical Information Service (NTIS)

Yucca Mountain is being investigated as a potential site for a high- level nuclear waste repository. The intent of this study was to clarify stratigraphic relations within the Paintbrush Tuff (PTn) unit at Yucca Mountain in order to better understand vert...

T. C. Moyer J. K. Geslin L. E. Flint

1996-01-01

383

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

Microsoft Academic Search

The Blue Nile Basin, situated in the Northwestern Ethiopian Plateau, contains ? 1400 m thick Mesozoic sedimentary section underlain by Neoproterozoic basement rocks and overlain by Early-Late Oligocene and Quaternary volcanic rocks. This study outlines the stratigraphic and structural evolution of the Blue Nile Basin based on field and remote sensing studies along the Gorge of the Nile. The Blue

N. D. S. GANI; M. G. Abdelsalam; S. Gera; M. R. Gani

2009-01-01

384

Use of amplitude vs offset seismic techniques to delineate subtle stratigraphic traps - Three field studies  

Microsoft Academic Search

Three stratigraphically trapped Wyoming fields which were previously held to be seismically invisible have been examined using amplitude vs. offset seismic techniques. This technology examines the seismic signature changes which take place as a function of source and receiver distance. Such signature changes are directly related to lithology and can be predicted in models and confirmed by the actual data.

J. E. Holton; C. D. Lausten; J. E. Blott

1989-01-01

385

Structural and stratigraphic controls on cave development in the Oak Ridge area, Tennessee  

SciTech Connect

The Oak Ridge Reservation (ORR) is located in the northwestern part of the Valley and Ridge province in east Tennessee. The Valley and Ridge province is the topographic expression of the southern Appalachian foreland fold-thrust belt, which formed during the late Paleozoic Alleghanian orogeny. In the Oak Ridge area, three major northwest verging thrust faults (Kingston, Whiteoak Mountain, and Copper Creek) imbricate and juxtapose carbonate and clastic stratigraphic units that range in age from the lower Cambrian to the lower Mississippian. The carbonate stratigraphic units range in thickness from 1278 to 1748 m and include the Maynardville Limestone in the Conasauga Group (hereby included as part of the Knox Group), the Knox Group, and the Chickamauga Group. Stratigraphic relationships and repetition of units by thrust faulting has produced three northeast striking and southeast dipping carbonate bands bounded to the northwest and southeast by noncarbonate units. Preliminary results indicate that within two of these carbonate bands, formations composed of mudstone and argillaceous limestone appear to further subdivide groundwater basins. Our efforts have focused on relating the stratigraphic and structural characteristics of these rock units with cave development in the region.

Rubin, P.A.; Lemiszki, P.J.

1992-12-31

386

Structural and stratigraphic controls on cave development in the Oak Ridge area, Tennessee  

SciTech Connect

The Oak Ridge Reservation (ORR) is located in the northwestern part of the Valley and Ridge province in east Tennessee. The Valley and Ridge province is the topographic expression of the southern Appalachian foreland fold-thrust belt, which formed during the late Paleozoic Alleghanian orogeny. In the Oak Ridge area, three major northwest verging thrust faults (Kingston, Whiteoak Mountain, and Copper Creek) imbricate and juxtapose carbonate and clastic stratigraphic units that range in age from the lower Cambrian to the lower Mississippian. The carbonate stratigraphic units range in thickness from 1278 to 1748 m and include the Maynardville Limestone in the Conasauga Group (hereby included as part of the Knox Group), the Knox Group, and the Chickamauga Group. Stratigraphic relationships and repetition of units by thrust faulting has produced three northeast striking and southeast dipping carbonate bands bounded to the northwest and southeast by noncarbonate units. Preliminary results indicate that within two of these carbonate bands, formations composed of mudstone and argillaceous limestone appear to further subdivide groundwater basins. Our efforts have focused on relating the stratigraphic and structural characteristics of these rock units with cave development in the region.

Rubin, P.A.; Lemiszki, P.J.

1992-01-01

387

Mesozoic stratigraphic constraints on Laramide right slip on the east side of the Colorado Plateau  

Microsoft Academic Search

Regional, eastward trending piercing lines defined by stratigraphic truncations and depositional pinchouts in Jurassic and Cretaceous strata in north-central New Mexico allow 5 to 20 km of right slip between the eastern margin of the Colorado Plateau and the craton to the east in Laramide (Late Cretaceous Paleogene) and younger time. Estimates of 60 170 km of Laramide right slip

Lee A. Woodward; Orin J. Anderson; Spencer G. Lucas

1997-01-01

388

Implications of new stratigraphic data on volcanic hazard assessment for Nisyros volcano, Greece  

Microsoft Academic Search

The active quaternary Nisyros volcano, at the eastern end of the Aegean volcanic arc, is composed of a succession of lava flows, tephra layers and interbedded epiclastic deposits. The volcano is topped by a recent caldera, on average 4 km in diameter and 200 m in depth. A detailed geological map including 35 stratigraphic units (lava flows, tephra layers and

A. Volentik; L. Vanderkluysen; C. Principe; J. Hernandez; J. C. Hunziker

2003-01-01

389

Continental Permian and Triassic vertebrate localities from Algeria and Morocco and their stratigraphical correlations  

Microsoft Academic Search

Faunal lists of taxa from the continental Permian and Triassic vertebrate localities from Algeria (Zarzaitine Series) and Morocco (Argana Group) are reported and their stratigraphical implications discussed. The nectridean Diplocaulus minimus and a captorhinid moradisaurine support a Permian age (Ufimian-Kazanian) for the top of Member T2 of the Argana Group. The base of the Lower Sandstones of the Zarzaitine Series

N.-E. Jalil

1999-01-01

390

The role of integrated high resolution stratigraphic and geophysic surveys for groundwater modelling  

Microsoft Academic Search

This work sets out a methodology of integrated geological, hydrogeological and geophysical surveys for the characterization of contaminated sites. The flow model of the shallow aquifer in the Brindisi area (recognized to be at significant environmental risk by the Italian government) and the impact of an antrophic structure on the groundwater flow have been evaluated. The stratigraphic and hydrogeological targets

S. Margiotta; F. Mazzone; S. Negri; M. Calora

2008-01-01

391

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

SciTech Connect

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

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

1995-08-01

392

Stratigraphic architecture and gamma ray logs of deeper ramp carbonates (Upper Jurassic, SW Germany)  

Microsoft Academic Search

The objective of this paper is to contribute to the development of sequence stratigraphic models for extensive epicontinental carbonate systems deposited over cratonic areas. Epicontinental carbonates of the SW German Upper Jurassic were analysed in terms of microfacies, sedimentology and sequence stratigraphy based on 2.5 km of core, 70 borehole gamma ray logs and 24 quarries. Facies analysis revealed six

T. Pawellek; T. Aigner

2003-01-01

393

Uncertainty in the Age of Fossils and the Stratigraphic Fit to Phylogenies  

Microsoft Academic Search

The ages of first appearance of fossil taxa in the stratigraphic record are inherently associated to an interval of error or uncertainty, rather than being precise point estimates. Contrasting this temporal information with topologies of phylogenetic relationships is relevant to many aspects of evolutionary studies. Several indices have been proposed to compare the ages of first appearance of fossil taxa

Diego Pol; MARK A. NORELL

2006-01-01

394

The Modified Gap Excess Ratio (GER*) and the Stratigraphic Congruence of Dinosaur Phylogenies  

Microsoft Academic Search

Palaeontologists routinely map their cladograms onto what is known of the fossil record. Where sister taxa first appear as fossils at different times, a ghost range is inferred to bridge the gap between these dates. Some measure of the total extent of ghost ranges across the tree underlies several indices of cladistic\\/stratigraphic congruence. We investigate this congruence for 19 independent,

MATTHEW A. WILLS; PAUL M. BARRETT; Julia Heathcote

2008-01-01

395

Seismic stratigraphy and stratigraphic modelling of the South-eastern German Molasse Basin  

Microsoft Academic Search

Although the German Molasse Basin can be regarded as a mature hydrocarbon province, no regional sequence stratigraphic analysis has been carried out so far. We have studied seismic lines and well data from the region between the Isar and Inn rivers (SE Germany) that have been generously supplied by German oil companies (DEE, BEB, Mobil, RWE-DEA and Wintershall). Initial work

T. Aigner; J. Jin; P. Luterbacher

1995-01-01

396

Seismic stratigraphy and stratigraphic modelling of the South-eastern German Molasse Basin  

SciTech Connect

Although the German Molasse Basin can be regarded as a mature hydrocarbon province, no regional sequence stratigraphic analysis has been carried out so far. We have studied seismic lines and well data from the region between the Isar and Inn rivers (SE Germany) that have been generously supplied by German oil companies (DEE, BEB, Mobil, RWE-DEA and Wintershall). Initial work indicates that five major seismic sequences within three main depositional cycles are developed. The Alpine thrust belt to the south serves as the primary sediment source in the foreland basin. However, sedimentary infill mainly took place parallel to the basin axis. Our analysis suggests that the stratigraphic development of the Molasse Basin was mainly controlled by eustatic sea-level changes which caused the shoreline to shift in the W-E direction. The shifting of the depocenter axis in a N-S direction was controlled by the tectonic evolution of the thrust belt. The sea-level curve determined by seismic stratigraphy and well-derived subsidence curves have been used as input parameters for stratigraphic modelling, using the programs GeoMOD and PHIL. Basin-fill simulations with PHIL are in good agreement with the main features of the sequence stratigraphy and the distribution of the systems tracts observed in the study area. The qualitative sea-level curve for the German Molasse Basin derived from the seismostratigraphic analysis could be quantified by the stratigraphic exercises.

Aigner, T.; Jin, J.; Luterbacher, P. [Univerisitaet Tuebingen (Germany)

1995-08-01

397

Stratigraphic signature of the Vesuvius 79 AD event off the Sarno prodelta system, Naples Bay  

Microsoft Academic Search

Sedimentological and chemical analysis of gravity core samples, along with the interpretation of very high resolution, single channel seismic reflection profiles acquired off the Sarno prodelta system (southeastern Naples Bay), document the sedimentary facies and seismic stratigraphic signature of the tephra deposit erupted by Vesuvius during the plinian eruption of 79 AD.The 79 AD pyroclastic deposits sampled off the Sarno

M. Sacchi; D. Insinga; A. Milia; F. Molisso; A. Raspini; M. M. Torrente; A. Conforti

2005-01-01

398

United States Offshore Wind Resource Assessment  

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

399

4-D stratigraphic architecture and 3-D reservoir zonation of the Mirado Formation, Cusiana Field, Colombia  

SciTech Connect

A high-resolution sequence stratigraphic study using 2300 feet of core calibrated with geophysical logs from 14 wells and 1800 measurements of porosity and permeability established the 4-D stratigraphy and 3-D reservoir zonation of the Mirador. Virtually all reservoir-quality facies are through cross-stratified sandstones which occur in channel facies successions in the lower Mirador, but in bay-head delta and estuarine channel facies successions in the upper Mirador. Petrophysical properties and the geometry, continuity and volume of reservoir-quality sandstones change regularly as function of their stratigraphic position. These vertical facies successions reflect increasing accommodation-to-sediment supply (A/S) ratio through each intermediate-term cycle. The upper long-term cycle comprises four intermediate-term, landward-stepping, symmetrical base-level cycles. These cycles consist of estuarine channel, bay-head to bay-fill facies successions. The transition from channel to bay-head to bay-fill facies successions represents an increase in A/S ratio, and the reverse transition indicates a decrease in A/S ratio. Sixteen reservoir zones were defined within the Cusiana field. Reservoirs within the upper and lower long-term cycles are separated by a continuous middle Mirador mudstone which creates two large reservoir divisions. At the second level of zonation, the reservoir compartments and fluid-flow retardants coincide with the intermediate-term stratigraphic cycles. A third level of reservoir compartmentalization follows the distribution of facies successions within the intermediate-term cycles. A strong stratigraphic control on reservoir properties occurs at the three scales of stratigraphic cyclicity. In all cases as A/S ratio increases, porosity and permeability decrease.

Fajardo, A.A. (Ecopetrol, del Petroleo (Colombia)); Cross, T.A. (Colorado School of Mines, Golden, CO (United States))

1996-01-01

400

Petroleum prospects for offshore sedimentary basins in the eastern Papua New Guinea and Solomon Islands regions  

SciTech Connect

Intra-arc basins in the Buka-Bougainville region of Papua New Guinea and in the Solomon Islands contain thick sedimentary sequences that may be prospective for petroleum. The Queen Emma basin, between Bougainville and New Ireland, contains as much as 8 km of deformed Oligocene and younger strata. The Central Solomons Trough, which underlies New Georgia Sound, is a composite intra-arc basin that contains late Oligocene and younger strata as much as 7 km thick. Farther east, beneath Indispensable Strait, the down-faulted Indispensable basin locally contains as much as 5.4 km of Miocene( ) and younger strata, and the offshore part of Mbokokimbo basin off eastern Guadalcanal includes 6 km or more of late Miocene and younger strata. All of these basins have some of the attributes necessary to generate and trap petroleum. Structural and stratigraphic traps are common, including faulted anticlines, sedimentary wedges, and carbonate reefs and reef-derived deposits on submarine ridges and along the basin margins. The thickness of the basin deposits ensures that some strata are buried deeply enough to be within the thermal regime required for hydrocarbon generation. However, little source or reservoir rock information is available because of the lack of detailed surface and subsurface stratigraphy. Moreover, much of the basin sediment is likely to consist of volcaniclastic material, derived from uplifted volcanogenic rocks surrounding the basins, and may be poor in source and reservoir rocks. Until additional stratigraphic information is available, analysis of the petroleum potential of these basins is a matter of conjecture.

Bruns, T.R.; Vedder, J.G. (Geological Survey, Menlo Park, CA (USA))

1990-06-01

401

Risk analysis for Arctic offshore operations  

SciTech Connect

Offshore exploration for hydrocarbons is being conducted in the near-shore regions of the Beaufort Sea. This activity is expected to be intensified and expanded into the deeper portions of the Beaufort, as well as into the Chukchi Sea. The ice conditions in the Beaufort Sea are very variable, particularly in the deeper water regions. This variability greatly influences the probability of success or failure of an offshore operation. For example, a summer exploratory program conducted from a floating drilling unit may require a period of 60 to 100 days on station. The success of such a program depends on: (a) the time when the winter ice conditions deteriorate sufficiently for the drilling unit to move on station; (b) the number of summer invasions by the arctic ice pack, forcing the drilling unit to abandon station; (c) the rate at which first-year ice grows to the ice thickness limit of the supporting icebreakers; and (d) the extent of arctic pack expansion during the fall and early winter. In general, the ice conditions are so variable that, even with good planning, the change of failure of an offshore operation will not be negligible. Contingency planning for such events is therefore necessary. This paper presents a risk analysis procedure which can greatly benefit the planning of an offshore operation. A floating drilling program and a towing and installation operation for a fixed structure are considered to illustrate the procedure.

Slomski, S.; Vivatrat, V.

1986-04-01

402

Apparatus for producing oil and gas offshore  

Microsoft Academic Search

An apparatus is described for producing oil or gas from an offshore oil or gas well using a production platform near or above sea-level which is laterally and vertically displaceable by the sea and wind and which permits well workover from the production platform, comprising: (a) the following elements of a Christmas tree located at about the seafloor: a first

Tam

1978-01-01

403

Embedded knowledge and offshore software development  

Microsoft Academic Search

Offshore software development scenarios may include groups with domain specific knowledge who collaborate internationally across multiple local contexts. A key challenge in the understanding and also practice of such distributed work is concerned with the issue of knowledge, and how it can be effectively managed. In this paper, we develop a conceptual scheme based on theories associated with embedded knowledge.

Brian Nicholson; Sundeep Sahay

2004-01-01

404

Petroleum geology framework, West Coast offshore region  

Microsoft Academic Search

The west coast offshore region of western Canada is a large, relatively- unexplored frontier hydrocarbon province. It includes Queen Charlotte (QC) and Georgia basins on the continental shelf inboard of Queen Charlotte Islands and Vancouver Island, and Tofino and Winona basins on the continental shelf and slope west of Vancouver Island (Fig. 1). A number of exploration wells drilled on

James W. Haggart; James R. Dietrich; Henry V. Lyatsky

405

Offshore and underground power plants 1977  

Microsoft Academic Search

Unconroversial plant sites for generating electric power by any means are becoming increasingly scarce. Both nuclear and fossil fuel plants require nearness to large quantities of cooling water and to load centers. The following topics are discussed: underground pumped storage; underground power plants; floating shallow water nuclear plants; floating deepwater nuclear plants; seabed and island nuclear plants; offshore coal fired

Noyes

1977-01-01

406

Off-Shoring: An Elusive Phenomenon.  

National Technical Information Service (NTIS)

This is the first of several reports by an Academy Panel formed to assess off-shoring, including the adequacy of current data and their usefulness in ascertaining its extent and economic effects. The Panel finds that the use of multiple terms to describe ...

2006-01-01

407

Accord near for offshore California oil shipments  

SciTech Connect

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

Not Available

1993-02-15

408

Offshore Essaouira basin: Geology and hydrocarbon potential  

Microsoft Academic Search

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

H. Jabour; A. Ait Salem

1991-01-01

409

Energy technologies for offshore frontier areas  

Microsoft Academic Search

Disappointing exploration results in Arctic and deepwater areas have prompted the Department of the Interior to lower their estimates of economically recoverable oil and gas resources in the U.S. offshore. Exploration and development of these resources is financially risky because of the costly high-technology systems and large investments needed to operate in frontier areas. If the country is to meet

J. Curlin; P. Johnson; C. Stevens; W. Westermeyer; D. Kevin; N. Harllee; C. Dybas

1985-01-01

410

Optimal routing offshore helicopter using Genetic Algorithm  

Microsoft Academic Search

This With the discovery of oil in the Pre-Salt layer, in oceanic regions of Brazil, it is aroused the need to improve technological devices of analysis, to ensure the sustainability of the system of fuel production in the country. From there we conjecture about the problem of air traffic control of offshore helicopters, which give logistical support to oil platforms

Allan Motta; Roberta Vieira; Joao Soletti

2011-01-01

411

Exploration and development offshore southern Vietnam  

Microsoft Academic Search

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

1996-01-01

412

Offshore Benin, a classic passive margin  

Microsoft Academic Search

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

1991-01-01

413

Federal offshore statistics: leasing, exploration, production, revenue  

Microsoft Academic Search

This publication 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

Essertier

1984-01-01

414

Deep water riser system for offshore drilling  

Microsoft Academic Search

A buoyant riser system for use in a deep water offshore drilling environment is anchored by a system of compliant guys below the active weather zone of the sea. A controllably buoyant housing of the system is submerged at a depth that is readily accessible to divers and includes a blow-out preventer (BOP) from which a suspended sub-riser leads to

1984-01-01

415

Innovative Offshore Engineering In The Arctic  

Microsoft Academic Search

Petroleum exploration in the past few years has been carried out in increasingly hostile environments; in the frigid northern tundra; in deep offshore waters and now in the ice infested seas in Arctic and sub-Arctic areas. In order to explore for oil in these hostile areas, in a cost effective manner, innovative solutions have been sought and implemented, such as

P. Noble

1983-01-01

416

Unique wellhead solves offshore cementing problems  

SciTech Connect

A special subsea wellhead assembly that allows 2stage cementing (from both top and bottom) in weak, unconsolidated seabed sediments has been used successfully from a semi-submersible rig offshore Malta. Presented here is a description of the system and a discussion of operational considerations used to set and cement 20 and 16-in. surface casing strings.

Not Available

1985-02-01

417

Sea loads on ships and offshore structures  

Microsoft Academic Search

The book introduces the theory of the structural loading on ships and offshore structures caused by wind, waves and currents, and goes on to describe the applications of this theory in terms of real structures. The main topics described are linear-wave induced motions, loads on floating structures, numerical methods for ascertaining wave induced motions and loads, viscous wave loads and

O. M. Faltinsen

1990-01-01

418

Economic Optimization of Offshore Wind Farms.  

National Technical Information Service (NTIS)

In this thesis, a recently developed cost model is extended and applied on site and design analyses as well as global design optimizations. The model provides a cost analysis for offshore wind farms from 14 to 120 MW installed power. With restrictions, it...

T. Pauling

1996-01-01

419

Reliability model of large offshore wind farms  

Microsoft Academic Search

For investors of wind farms projects, it is indispensable to get reliable prognosis of the expected energy produced per year, taking into account technical failures and the stochastic characteristic of the wind. This applies especially for offshore wind farms with higher installation costs and difficult maintenance conditions. The repair of components located on sea may take many days or even

E. Spahic; A. Underbrink; V. Buchert; J. Hanson; I. Jeromin; G. Balzer

2009-01-01

420

A New Architecture for Offshore Wind Farms  

Microsoft Academic Search

Offshore wind farms using HVDC links can be positioned a large distance from shore, opening up new opportunities for wind generation. Conventional approaches using 60 Hz generators and transformers are not appropriate in such applications, as they are heavy and result in expensive and complex installation and maintenance issues. This paper proposes an alternative architecture for such wind farms, using

Anish Prasai; Jung-Sik Yim; Deepak Divan; Ashish Bendre; Seung-Ki Sul

2008-01-01

421

Experimental study of an offshore platform.  

National Technical Information Service (NTIS)

This report describes the results of an analysis of the ambient response data collected from a Venezuelan near-shore offshore platform constructed in 1992. Recording of the data have been constantly done during the period from May 1993 to July 1994. Using...

P. H. Kirkegaard J. C. Asmussen P. Andersen R. Brinker

1994-01-01

422

Damage detection in an offshore structure.  

National Technical Information Service (NTIS)

The structural integrity of a multi-pile offshore platform is investigated by using a vibration based damage detection scheme. Changes in structural integrity are assumed to be reflected in the modal parameters estimated form only output data using an Aut...

R. Brincker P. H. Kirkegaard P. Andersen M. E. Martinez

1994-01-01

423

Fatigue failure paths for offshore platform inspection  

Microsoft Academic Search

A closed- form, reliability-based procedure is developed to identify fatigue failure paths of offshore structures and assess the notional probability of system failure through these paths. The procedure utilizes the Miners rule node fatigue failure reliability model developed by Wirsching. Effects of load redistribution following the fatigue failure of a node on the time to failure of remaining unfailed nodes

Demir I. Karsan; Ashok Kumar

1990-01-01

424

Integrating Offshore Wind and Wave Resource Assessment  

Microsoft Academic Search

The aim of this paper is to review the sources of wind and wave information, the methodologies to assess offshore wind and wave energy resources, and the more relevant results at the European level as a first step to integration of the evaluation of both resources. In situ and remote sensed wind and wave data (using satellite based sensors) are

M. T. Pontes; R. Barthelmie; G. Giebel; P. Costa; A. Sood

425

Offshore production riser with flexible connector  

Microsoft Academic Search

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

E. C. Blomsma; P. T. Holtslag

1981-01-01

426

Flow line riser for offshore structure  

Microsoft Academic Search

Riser for an offshore marine platform which includes facilities to receive, treat, and\\/or store hydrocarbon fluid from a plurality of dispersed submerged wells. The riser includes means to accommodate a plurality of conduits between the platform deck and the floor of the body of water. As a rigid, or non-rigid conduit is pulled downwardly through the riser, it engages a

J. P. Knowles; S. D. Mitchell; S. Wheeler

1985-01-01

427

Human Rights, Academic Freedom, and Offshore Academics  

ERIC Educational Resources Information Center

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

Ross, Andrew

2011-01-01

428

Human Rights, Academic Freedom, and Offshore Academics  

ERIC Educational Resources Information Center

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

Ross, Andrew

2011-01-01

429

Wave Models for Offshore Wind Turbines  

Microsoft Academic Search

In the design of wind turbines—onshore or offshore—the prediction of extreme loads as- sociated with a target (long) return period requires statistical extrapolation from available loads data. The data required for such extrapolation are obtained by stochastic time- domain simulation of the inflow turbulence and of the turbine response. Prediction of accurate loads depends on assumptions made in the simulation

Puneet Agarwal; Lance Manuely

2008-01-01

430

Meren field water injection project offshore Nigeria  

Microsoft Academic Search

The Meren Water Injection Project, which is one of the largest in West Africa in terms of injection volume, secondary reserves to be recovered and cost, is located in the Meren field offshore Nigeria. This study presents an updated comprehensive plan to deplete 7 reservoir units in sands that have been producing under solution gas drive and gravity segregation with

Adetoba

1984-01-01

431

Offshore accidents and effects on their performances  

Microsoft Academic Search

Marine accidents are some of the risk sources on human life at sea and also make the founded budget to be sank to the deep. In order to prevent these damages and losses, it is necessary to do a proper understanding of these accidents. Offshore systems as of the main parts of ocean structures and their accidents are considered here

H. Sayyaadi; P. Hemati

2004-01-01

432

Status and challenges for offshore wind energy  

Microsoft Academic Search

Worldwide demand for renewable energy is increasing rapidly because of the climate problem, and also because oil resources are limited. Wind energy appears as a clean and good solution to cope with a great part of this energy demand. As space is becoming scarce for the installation of onshore wind turbines, offshore wind energy becomes a good alternative. Renewable electricity

Rennian Li; Xin Wang

2011-01-01

433

Correcting relative paleointensity records for variations in sediment composition: Results from a South Atlantic stratigraphic network  

NASA Astrophysics Data System (ADS)

Marine sediments record direction and intensity of the Earth's magnetic field by the alignment of magnetic particles during deposition. For determining relative paleointensity (RPI) from sediment records it is commonly assumed that their natural remanent magnetization (NRM) is proportional to the Earth's magnetic field during deposition, and also proportional to the concentration of remanence carriers in the sediment layer. However, little is known how varying sediment composition and environmental conditions during deposition influence the NRM. Here we try to identify and quantify such sedimentary influences for eight sediment series from the subtropical and subantarctic South Atlantic. The cores were recovered in a constraint area crossing the subtropical front (STF). They have widely different sediment lithologies, which can be divided into three lithologic groups. Due to their mutual proximity, they have experienced approximately the same magnetic field history, and differences in their RPI signals must be caused by their varying sediment composition and recording properties. Based on high resolution rock magnetic and compositional data from two previous studies it is possible to quantitatively test and compare the influences of different sediment properties upon the NRM. It is found that magnetic grain size, as measured by the magnetic parameter ARM/IRM, is most influential among the parameters tested. Weak to moderate reductive diagenesis, as measured by the parameter Fe/?, turns out to have minor impact. By comparing the sensitivity of different normalization procedures for RPI determination, it is found that induced remanent magnetization (IRM) is most robust. Based on an extended linear RPI theory, we can calculate a corrected RPI stack for the investigated cores. This correction improves the correlation with independent global paleointensity stacks in comparison to our previous uncorrected RPI stack (Hofmann, D., Fabian, K., 2007. Rock-magnetic properties and relative paleointensity stack for the last 300 ka based on a stratigraphic network from the subtropical and subantarctic South Atlantic. Earth Planet. Sci. Lett. 260, 297-312.). The ratio between corrected and uncorrected RPI stacks reveals a hidden global climate signal, which indicates that climatic variations in sediment composition are inevitably present in non-ideal sediment sequences.

Hofmann, Daniela I.; Fabian, Karl

2009-06-01

434

Divergent evolutionary processes associated with colonization of offshore islands.  

PubMed

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

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

2013-09-03

435

Evaluation of FCAW consumables of offshore and Arctic structure fabrication  

SciTech Connect

A primary consideration in the welding of structures for service in Canadian offshore and arctic regions is the toughness of weld metals required at very low ambient temperatures ([minus]30 C to [minus]60 C). To assess the suitability of cored wires for applications in these environments, some currently available commercial consumables for the flux-cored arc welding (FCAW) process were evaluated. Cored wires belonging to four different categories: basic, rutile, metal-cored and innershield, were used to prepare welds with similar welding procedures. Weld metal Charpy V-notch (CVN) and crack tip opening displacement (CTOD) tests were carried out and the effect of weld metal composition, microstructure and inclusion content in the weld metal toughness was examined. The Charpy transition temperatures and the CTOD toughness results indicated that, of the 16 wires tested, there were only seven that would be suitable for critical applications.

Bala, S.R. (Welding Inst. of Canada, Oakville, Ontario (Canada)); Malik, L. (Fleet Technology Ltd., Kanata, Ontario (Canada)); Braid, J.E.M. (Metals Technology Labs., Ottawa, Ontario (Canada))

1993-02-01

436

Shallow stratigraphic control on pockmark distribution in north temperate estuaries  

USGS Publications Warehouse

Pockmark fields occur throughout northern North American temperate estuaries despite the absence of extensive thermogenic hydrocarbon deposits typically associated with pockmarks. In such settings, the origins of the gas and triggering mechanism(s) responsible for pockmark formation are not obvious. Nor is it known why pockmarks proliferate in this region but do not occur south of the glacial terminus in eastern North America. This paper tests two hypotheses addressing these knowledge gaps: 1) the region's unique sea-level history provided a terrestrial deposit that sourced the gas responsible for pockmark formation; and 2) the region's physiography controls pockmarks distribution. This study integrates over 2500 km of high-resolution swath bathymetry, Chirp seismic reflection profiles and vibracore data acquired in three estuarine pockmark fields in the Gulf of Maine and Bay of Fundy. Vibracores sampled a hydric paleosol lacking the organic-rich upper horizons, indicating that an organic-rich terrestrial deposit was eroded prior to pockmark formation. This observation suggests that the gas, which is presumably responsible for the formation of the pockmarks, originated in Holocene estuarine sediments (loss on ignition 3.5–10%), not terrestrial deposits that were subsequently drowned and buried by mud. The 7470 pockmarks identified in this study are non-randomly clustered. Pockmark size and distribution relate to Holocene sediment thickness (r2 = 0.60), basin morphology and glacial deposits. The irregular underlying topography that dictates Holocene sediment thickness may ultimately play a more important role in temperate estuarine pockmark distribution than drowned terrestrial deposits. These results give insight into the conditions necessary for pockmark formation in nearshore coastal environments.

Brothers, Laura L.; Kelley, Joseph T.; Belknap, Daniel F.; Barnhardt, Walter A.; Andrews, Brian D.; Legere, Christine; Hughes-Clarke, John E.

2012-01-01

437

Marine biofouling in offshore areas south of Hainan Island, northern South China Sea  

Microsoft Academic Search

This study on the characteristics of fouling communities in offshore areas south of Hainan Island, northern South China Sea,\\u000a was conducted at four sites there. At each station, test panels on iron frames were hung on the mooring system at different\\u000a depths. Data on biofouling were mainly obtained by examination of the fouled test panels. Organisms attached to buoys and

Tao Yan; Wen-Xia Yan; Guan-He Liang; Yu Dong; Hua-Jie Wang; Yan Yan

2000-01-01

438

Time-stratigraphic correlation of lower Wilcox valley-fill sequences, Colorado and Lavaca Counties, Texas  

SciTech Connect

Late Paleocene and early Eocene lower Wilcox strata in southeast Texas are characterized principally by sandstone-rich deposits of fluvial and deltaic systems that prograded from a stable platform area into an unstable growth-faulted shelf margin setting. In contrast, incised valley systems, initiated during episodes of sea level lowering and filled dominantly with mud during subsequent transgressions, punctuate several lower Wilcox intervals. Further, valley-fill sequences are known to provide seals and/or reservoirs for a number of stratigraphically trapped hydrocarbon accumulations. Time-stratigraphic correlation of lower Wilcox strata provides improved differentiation of stacked valley-fill sequences and thereby more refined interpretation of depositional history and more accurate mapping for exploration purposes.

Devine, P.E.; Wheeler, D.M. (RPI International, Boulder, CO (USA))

1989-09-01

439

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

SciTech Connect

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

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

1996-01-01

440

Cenozoic tectonics of the Caribbean: Structural and stratigraphic studies in Jamaica and Hispaniola  

NASA Astrophysics Data System (ADS)

Structural and stratigraphic field studies in Jamaica and Hispaniola (Dominican Republic and Haiti) and synthesis of published data from surrounding areas refine previously proposed models for convergent and strike-slip plate interactions in the northern Caribbean. Specifically: (1) new data and regional stratigraphic analysis of major unconformities in the Greater Antilles supports the idea of two distinct arcs that terminated by collision at slightly different times in the latest Cretaceous and Paleogene; (2) field studies in the Port Maria area of northeastern Jamaica essentially complete mapping of the Wagwater Belt, a reactivated Paleogene graben and overlying sedimentary basin; and (3) the interpretation of satellite imagery and aerial photographs and field studies in the Enriquillo Valley and Sierra el Numero, Dominican Republic; the Culde-Sac Valley and southern peninsula of Haiti; and the Clydesdale area of eastern Jamaica.

Mann, W. P.

441

Lithofacies variation across the Mammoth Cave-Pope Megagroup boundary -- a sequence stratigraphic approach  

Microsoft Academic Search

Regional stratigraphic relations in southern Illinois suggest a major unconformity near the top of the St. Genevieve Limestone. Large exposures below the unconformity within the Anna quarries display a retrogradational parasequence-stacking pattern. Eight to 12 m-thick parasequences comprise thinning-upward marine bioclastic wackestone overlain by oolitic and bioclastic thickening-upward eolian( ) grainstone. An eolian origin for the bioclastic grainstones is supported

T. A. McDonald; E. Tabor; J. E. Marzolf

1994-01-01

442

Stratigraphic and interregional changes in Pennsylvanian coal-swamp vegetation: Environmental inferences  

Microsoft Academic Search

Phillips, T.L., Peppers, R.A. and DiMichele, W.A,, 1985. Stratigraphic and interregional changes in Pennsylvanian coal-swamp vegetation: Environmental inferences. In: T.L. Phillips and C.B. Cecil (Editors), Paleoclimatic Controls on Coal Resources of the Pennsylvanian System of North America. Int. J. Coal Geol., 5: 43—109. Quantitative analysis of Pennsylvanian coal-swamp vegetation provides a means of in- ferring organization and structure of communities.

TOM L. PHILLIPS; RUSSEL A. PEPPERS; WILLIAM A. DIMICHELE

1985-01-01

443

Seismic reflection character analysis of stratigraphic traps in Cretaceous Cardium Formation, Alberta, Canada  

Microsoft Academic Search

The Cretaceous Cardium Formation, Alberta, Canada, produces oil and gas from thin sandstone stratigraphic traps. The formation can be subdivided into the Cardium sand and overlying Cardium zone. over a 4,000 mi² (10,000 km²) study area, the Cardium zone decreases in thickness from 80-120 ft (24-36 m) in the northwest to about 40 ft (12 m) in the east. Sandstone

R. M. Slatt; J. C. Robinson; K. A. Lighty; G. F. Moore

1987-01-01

444

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

Microsoft Academic Search

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

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

2007-01-01

445

Sequence-stratigraphic concepts applied to integrated oil and gas field development, with case histories  

Microsoft Academic Search

Sequence-stratigraphy is the study of genetically related strata that are bounded by unconformities (or their correlative conformities). Facies models are used to interpret the genetically related strata and must be developed to interpret accurately the unconformities. Sequence-stratigraphic concepts have been used to analyze the petroleum geology of a 320 mi² (900 km²) producing area on the east flank but near

Weimer

1994-01-01

446

Stratigraphic diatom and chemical evidence for acid strip-mine lake recovery  

Microsoft Academic Search

Stratigraphic analyses of diatoms and chemical compounds in a sediment core were utilized to investigate the recovery of an acid strip-mine lake in southern Ohio. The chemical stratigraphy suggests that chemical recovery of the lake, defined as the rise and maintenance of water pH at values above 4.5, is a discrete process marked in the core by a sharp rise

Sherilyn C. Fritz; Robert E. Carlson

1982-01-01

447

Origin and stratigraphic assessment of pre-Mt. Simon clastics (Precambrian) of Michigan basin  

Microsoft Academic Search

Previous workers have synthesized the results of recent deep drilling in the Michigan basin with the concept of Keweenawan rifting. Their model correlates the pre-Mt. Simon clastics in the Sparks et al 1-8 well with those in the State-Beaver Island 1 well, identifies them both as turbidites, and places the pre-Mt. Simon sequence stratigraphically higher in the section than the

Catacosinos

1981-01-01

448

Stratigraphic occurrences of iridium anomalies at four Cretaceous\\/Tertiary boundary sites in New Zealand  

Microsoft Academic Search

Three new iridium anomaly sites have been discovered in Cretaceous\\/Tertiary boundary sequences in New Zealand. These are at Needles Point, Chancet Rocks, and Waipara, where integrated iridium deposition values were 165, 211, and 7 ng\\/cm2, respectively. In contrast to the previously reported Woodside Creek stratigraphic sequence that had an iridium anomaly of 187 ng\\/cm2, a ferruginous boundary clay is absent

Robert R. Brooks; C. Percy Strong; Julian Lee; Charles J. Orth; James S. Gilmore; Douglas E. Ryan; Jiri Holzbecher

1986-01-01

449

GNULEX - new online USGS database of stratigraphic nomenclature for US western interior  

SciTech Connect

Accurate and up-to-date information on the definitions of stratigraphic units is essential to both industry and academic activities in the earth sciences. In order to encourage accurate use of stratigraphic nomenclature, they are compiling a new database - GNULEX - which contains comprehensive information on stratigraphic units of the US Western interior (from the Mississippi River to the western borders of Idaho, Utah, and Arizona). The information is from published reports of all major earth science journals dating from the first published use of the unit to the present day. A user selects records either by stratigraphic unit name or by user-specified attributes. These attributes include age (era, period, epoch, or stage), formal rank, state, geologic province or basin, lithologic type, author, and type of information (biostratigraphic dating, isotopic dating, etc) - all attributes may be logically linked to tailor the search for individual needs. The record for each unit is divided into (1) an up-to-date summary that includes rank terms, assigned ages, a detailed description of the type locality (if designated), and area of occurrence (states and geologic provinces or basins) and (2) a historical record that contains critical information abstracted from publications that have defined the unit or modified its definition. This large and growing database was developed and is maintained by the US Geological Survey in Denver, Colorado, on a supermini-class networking computer and may be accessed by other computers with 1200-baud communications capability. Output is to the screen only and on-line help files are available. You may access the database free of charge via modem for the price of your telephone call.

MacLachlan, M.E.; Bryant, W.A.; Stone, L.M.; Judkins, T.W.

1988-02-01

450

Seismic reflection character analysis of stratigraphic traps in Cretaceous Cardium Formation, Alberta, Canada  

SciTech Connect

The Cretaceous Cardium Formation, Alberta, Canada, produces oil and gas from thin sandstone stratigraphic traps. The formation can be subdivided into the Cardium sand and overlying Cardium zone. over a 4,000 mi{sup 2} (10,000 km{sup 2}) study area, the Cardium zone decreases in thickness from 80-120 ft (24-36 m) in the northwest to about 40 ft (12 m) in the east. Sandstone beds, some of which are stratigraphic traps, are interbedded with shale in the thicker northwest section. Sandstone beds are absent toward the east. The underlying Cardium sand increases in thickness from about 40 ft (12 m) in the west to 160 ft (48 m) in the east; this increase in thickness corresponds to an increase in shale and decrease in thick-bedded sandstones. An analysis of 97 seismic lines in the study area indicates that two major seismic reflection patterns comprise the Cardium Formation seismic interval. One pattern consists of two seismic reflections spaced 20-40 msec apart, and the other pattern consists of a single reflection. These two patterns can be mapped across a large area. The areal distribution of the double seismic reflection pattern corresponds approximately to the occurrence of sandstone beds in the Cardium zone. This study further demonstrates that sandstone stratigraphic traps and associated facies can be more accurately mapped using a combination of well logs and field seismic records than by using well control alone. 12 figs., 1 tab.

Slatt, R.M.; Robinson, J.C.; Lighty, K.A.; Moore, G.F. (Cities Service Oil and Gas Corp., Tulsa, OK (USA))

1987-03-01

451

Stratigraphic expressions of the Holocene–Anthropocene transition revealed in sediments from remote lakes  

NASA Astrophysics Data System (ADS)

Stratigraphic boundaries are ideally defined by distinct lithological, geochemical, and palaeobiological signatures, to which a chronological framework can be applied. We present a range of observations that illustrate how the Holocene-Anthropocene transition meets these criteria in its expression in sediments from remote arctic and alpine lakes, removed from direct, catchment-scale, anthropogenic influences. In glaciated lake basins, the retreat of glaciers commonly leads to lithological successions from proglacial clastic sedimentation to non-glacial organic deposition. Sediments from the majority of lakes record marked depletions in the nitrogen stable isotopic composition of sediment organic matter, reflecting anthropogenic influences on the global nitrogen cycle. In all cases, siliceous microfossil assemblages (diatoms and chrysophytes) change markedly and directionally, with regional nuances. These stratigraphic fingerprints begin to appear in the sediment record after AD 1850, but accelerate in pulses between AD 1950 and 1970 and again after AD 1980. Our review indicates that recent environmental changes associated with humankind's dominance of key global biogeochemical cycles are sufficiently pervasive to be imprinted on the sediment record of remote lakes. Moreover, these changes are of sufficient magnitude to conclude that the Holocene has effectively ended, and that the concept of Anthropocene more aptly describes current planetary dynamics. The synthesis of these observations pertains directly to ongoing discussions concerning the eventual formalization of a new stratigraphic boundary.

Wolfe, Alexander P.; Hobbs, William O.; Birks, Hilary H.; Briner, Jason P.; Holmgren, Sofia U.; Ingólfsson, Ólafur; Kaushal, Sujay S.; Miller, Gifford H.; Pagani, Mark; Saros, Jasmine E.; Vinebrooke, Rolf D.

2013-01-01

452

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

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

453

Perspectives of offshore geothermal energy in Italy  

NASA Astrophysics Data System (ADS)

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

Armani, F. B.; Paltrinieri, D.

2013-06-01

454

Offshore technology has a tremendous future  

SciTech Connect

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.

Brundage, H.T.

1984-05-01

455

Response of wave excited offshore platforms  

SciTech Connect

A study of the resultants of inertia and drag force components induced by waves on offshore structures is made, and the relations between these resultants and the corresponding modal forces that govern the structural response are examined. The information and concepts reported elucidate the main factors that control such forces. Using the deep-water approximation of linear wave theory and the Morison equation, it is shown that the inertia and drag components of the modal forces can be expressed in terms of the sea surface kinematics. This treatment of the wave excitations advances the understanding of their characteristics and contributes to forming a basis for efficient, reliable evaluations of the response of wave- excited offshore platforms.

Chang, Shih-Jung [Oak Ridge National Lab., TN (United States); Hahn, G.D. [Vanderbilt Univ., Nashville, TN (United States). Dept. of Civil and Environmental Engineering

1995-09-01

456

A high-resolution seismic survey of the Holocene section offshore part of the Dutch mesotidal barrier shoreline  

SciTech Connect

Genetic stratigraphy of the Holocene section offshore the Dutch mesotidal barrier islands Terschelling and Ameland was studied using a 220-mi-grid of both analog and digitally acquired high-resolution seismic records, obtained with a 300 Joule boomer and 10{sup 3}-in. air gun. The southern North Sea basin was subaerially exposed during the most recent (Wurm) Pleistocene lowstand and covered by glaciers during the previous (Saale) glacial. The Pleistocene surface in the area is approximately 30 m below the sediment surface and shows strong erosional and glaciotectonic characteristics. Holocene inundation began after 10 Ka. The investigated area has been fully marine since approximately 8 Ka. The Holocene energy regime has maximum tidal currents of 10-15 knots and a semidiurnal tide range of approximately 2 m. Pleistocene erosional relief may have been used for early Holocene tidal drainage, as evidenced by lateral accretion reflectors filling this relief. Locally, these reflectors become sigmoidal in expression, where they may represent early Holocene ebb-tidal deltas. This seismic expression is similar to that of recent ebb-tidal deltas in the area. In one location Holocene sediments offlap a Pleistocene topographic high. In the western part of the study area, the sea floor offshore the barrier island Terschelling is relatively flat. The Holocene section appears to consist of two transgressive stratigraphic units. The lower unit contains a number of coast-parallel sediment bodies, measuring roughly 3 {times} 7 {times} 5 m. It is uncertain at this time whether these represent either part of an early Holocene barrier island chain, or tidal ridges of that age. A number of approximately 2-3-m high sand ridges lies in a northwest-southeast section at an angle of approximately 25{degree}, with the present barrier shoreline offshore the barrier island Ameland in the eastern part of the area.

Kosters, E.C.; McGee, T.; Posthumus, B.; Brouwer, J. (Univ. of Utrecht (Netherlands))

1990-05-01

457

Protective riser-conductor for offshore structures  

SciTech Connect

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.

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

1985-07-09

458

Program analyzes offshore platform jacket template  

Microsoft Academic Search

Major computer analyses of steel offshore jacket templates sometimes suggest that certain structural tubular members are overstressed; however, the process of checking the bending and axial stresses by hand is tedious and time-consuming. TEL has thus prepared programs for the Hewlett-Packard HP-41C calculator that speedily perform such stress checks using the formulas of API RP2A, Section 2.5.2. The programs take

Cazeau

1980-01-01

459

Platforms will handle sour streams offshore India  

SciTech Connect

The recently installed Panna facilities, offshore the west coast of India, are designed to produce 50,000 b/d of highly paraffinic, sour oil, 180 MM-scfd of sour gas, and 100,000 bw/d. The field lies in about 154 ft of water. Enron Oil and Gas India Ltd. is operator. Enercon Engineering Inc., Houston, provided detailed design, procurement, and inspection services for the development that includes installation of six platforms and 22 pipelines.

NONE

1997-07-21

460

Analytical approximations for offshore pipelaying problems  

Microsoft Academic Search

1. Abstract The geometrically non-linear slender bar equation is solved for a number of problems involv- ing suspended pipelines, related to the off-shore gas- and oil-pipe laying. The problems concern the use of a lay-barge with stinger, and the process of abandoning and recovery of a pipe. The usually stiff equation requires for a completely numerical solution considerable computer power,

S. W. Rienstra

1987-01-01

461

Offshore production riser with flexible connector  

SciTech Connect

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

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

1981-06-16

462

Offshore installation of ocean outfalls diffuser assemblies  

SciTech Connect

The Sydney Water Board commissioned the design and construction of three subsea ocean outfalls to handle the sewage disposal needs of the area for the next 100 years. The outfalls consist of three underground tunnels, extending up to 3 miles (5 km) offshore, that connect with 93 riser shafts capped with diffuser heads and supported by caissons. This paper discusses the methods and equipment used to install those ocean outfalls.

Arnold, M.S.; Tait, S.A.

1990-06-01