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1

Norwegian Offshore Stratigraphic Lexicon (NORLEX)  

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

2

Sequence stratigraphic framework of Neogene strata in offshore Nigeria  

SciTech Connect

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

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

1996-08-01

3

Evaluation of untested stratigraphic traps in a Pleistocene Canyon-fill complex, offshore Louisiana  

SciTech Connect

Eugene Island Block 390, located approximately 100 mi offshore Louisiana was acquired by ARCO Oil and Gas Company in 1983 to test upper Pleistocene amplitude anomalies located on the faulted northwest flank of a diapiric salt structure. Although drilling has established the presence of oil and gas in the objective section, an attempt to delineate further reserve potential on the block was made by evaluating additional amplitude anomalies located downflank in an adjacent syncline. Seismic stratigraphic analysis indicates that the anomalies are located within the confines of an erosionally incised submarine canyon complex, approximately 3 mi wide and 500 ft deep. A number of high-amplitude events located in the upper part of the fill complex are interpreted to represent relatively coarser grained sandstone bodies, in contrast to the fine-grained material that represents the majority of the fill. In map view, these high-amplitude events are axially elongated, dip-trending bodies that were deposited laterally adjacent to one another. In the deepest parts of the ARCO 1 well, stratigraphically below their original objective, approximately 50 net ft of oil-saturated but very low-permeability silt and shale were encountered. Examination of the well location on seismic data indicates that the ARCO 1 well was drilled into in the canyon flank, updip from and laterally adjacent to the high-amplitude events. The interpretation is that the low permeability oil saturated sections seen in the ARCO 1 well is representative of the depositional transition into the seal facies. Therefore, the highest amplitude events located downdip of the ARCO 1 well are thought to represent stratigraphically trapped hydrocarbons reservoired within canyon-fill sands, an interpretation supported by positive amplitude vs. offset analysis results.

Geitgey, J.E. (ARCO Oil and Gas Co., Dallas, TX (USA))

1990-05-01

4

Stratigraphic test well, Nantucket Island, Massachusetts  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with the Massachusetts Water Resources Commission and the Nantucket Conservation Foundation, continuously cored 514 m of sediment and volcanic rock in a stratigraphic and water-quality test near the geographic center of Nantucket Island. Stratified sediments were divided texturally into three zones: the upper zone (0-128 m) contains mostly coarse sand and gravel; the middle zone (128-349 m) contains mostly silty clay and a few beds of sand and silt; and the lower zone (349-457 m) contains soft, unconsolidated, clayey sand. Below the lower zone, a saprolite, composed mostly of clay, grades abruptly downward at 470 m into partially altered basalt that extends to the bottom of the hole at 514 m. Calculations based on the Ghyben-Herzberg principle predicted a zone of freshwater 120-150 m thick. This principle is the theory of hydrostatic equilibrium between freshwater and more dense seawater in a coastal aquifer; it states that for each meter of ground-water elevation above sea level, the freshwater lens will depress the saltwater interface about 40 m below sea level. Freshwater or low-salinity brackish water was found in sediments far below the depth predicted by the Ghyben-Herzberg principle. These interstitial waters are probably relict ground water emplaced during times of low sea level during the Pleistocene. (Woodard-USGS)

Folger, David W.; Hathaway, J.C.; Christopher, R.A.; Valentine, P.C.; Poag, C.W.

1978-01-01

5

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

SciTech Connect

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

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

1990-05-01

6

KEY OIL TESTS AND STRATIGRAPHIC SECTIONS IN SOUTHWEST NEW MEXICO  

Microsoft Academic Search

Significantly thick stratigraphic sections of possibly petroliferous Paleozoic and Mesozoic strata are exposed in 15 mountain ranges and have been drilled in several wildcat oil tests in Hidalgo, Grant, Luna, and western Dona Ana Counties of southwest New Mexico. The deepest well, the Humble No. 1 State BA, was drilled to a total depth of 14,585 feet, and penetrated part

FRANK E. KOTTLOWSKI; ROY W. FOSTER; SHERMAN A. WENGERD

7

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

8

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

Microsoft Academic Search

The East Georges Bank Basin is located offshore Nova Scotia on the southeastern Canadian continental shelf. The basin covers 2.5 million ac and is one of the last undrilled basins in North America. The geological interpretation is almost entirely based on 16,000 km of seismic data over the basin. Pertinent well control is limited to 10 wells on the US

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

1990-01-01

9

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

Microsoft Academic Search

Lithologic variation, regional depositional trends, and the lack of written guidelines have resulted in inconsistencies in the recognition of stratigraphic contacts in drill holes at the Nevada Test Site (NTS). Stratigraphic identification, based on mineralogy of discrete samples, can be augmented by geophysical logs and downhole movies to more accurately and consistently locate contacts between units. Criteria are established for

G. A. Pawloski; H. L. McKague; J. L. Wagoner; W. B. McKinnis

1992-01-01

10

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

11

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

12

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

13

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  

Microsoft Academic Search

As part of an effort to identify suitable targets for a planned long-term field test, we investigate by means of numerical simulation the gas production potential from unit D, a stratigraphically bounded (Class 3) permafrost-associated hydrate occurrence penetrated in the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well on North Slope, Alaska. This shallow, low-pressure deposit has high porosities (? = 0.4),

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

2011-01-01

14

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

15

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

SciTech Connect

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

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

1992-01-01

16

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

17

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

18

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

Microsoft Academic Search

The BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well was drilled and cored from 606.5 to 760.1m on the North Slope of Alaska, to evaluate the occurrence, distribution and formation of gas hydrate in sediments below the base of the ice-bearing permafrost. Both the dissolved chloride and the isotopic composition of the water co-vary in the gas hydrate-bearing zones, consistent

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

2011-01-01

19

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

20

The Offshore New Harbor (ONH) Seismic Expedition: Revealing the Stratigraphic History in the Southern McMurdo Sound Region, Ross Sea, Antarctica from the Greenhouse to Icehouse Worlds  

NASA Astrophysics Data System (ADS)

In the austral spring 2008, the ANDRILL (ANtarctic geological DRILLing) Program’s Offshore New Harbor Expedition successfully collected over 48 km of multi-channel seismic (MCS) data to investigate the stratigraphic and tectonic history of westernmost Southern McMurdo Sound during the Greenhouse World (Eocene) and the start of the Icehouse World (Oligocene). This survey represents an important step for identifying future drilling targets for ANDRILL, which is a multinational program, with the aim to recover stratigraphic intervals for interpreting Antarctica’s climate and glacial history over the past 50 million years. The goal of the Offshore New Harbor Project is to recover proximal archives from two widely recognized but unresolved time intervals regarding Antarctica’s history: 1) the mid-Paleogene cryospheric development on Antarctica; and 2) the abrupt climate shift across the Eocene/Oligocene transition. The ONH seismic survey used methods successfully employed by previous ANDRILL’s surveys in Southern McMurdo Sound (2005) and in Mackay Sea Valley (2007), which included deploying a Generator Injector (G.I.) airgun through holes drilled through the ice and a 1.5 km long streamer that used 60 gimbled geophones to measure the returning reflected seismic energy. Processing of the seismic data was successfully able to remove the bottom water multiple, permitting deeper seismic reflectors to be identified for the first time in this area. Since one of the two seismic lines crossed close to the previously drilled CIROS-1, correlation was possible between the seismic reflectors and the entire stratigraphic section at CIROS-1, which has been dated as old as Late Eocene (~37 Ma). Additionally, seismic and gravity data indicated that a thick sedimentary wedge of up to 5 km lie immediately east of CIROS-1. With the Devonian Beacon Sandstone Formation having been observed to be no thicker than 2 km on land, an additional 3 km of Cenozoic sediments may lie below and down dip of CIROS-1. The Oligocene strata are characterized by a clinoformal geometry, with reflectors down lapping onto the two prominent reflectors that correspond to the Eocene / Oligocene Boundary and the “mid” Oligocene hiatus recognized in the CIROS-1 borehole. These new data support the idea that substantial Eocene and Oligocene strata can be recovered by drilling east of the location of the CIROS-1 borehole. The upper units imaged below the base of CIROS-1 represent the potential for future drilling objectives for the ANDRILL Program. Additionally, reflectors that contained trough-like shapes were interpreted as representing incised valleys, which were most likely cut by ice streams. These valleys provide prima facie documentation of when the ice sheet extended beyond the present-day coastline. These reflectors were correlated to CIROS-1 as well as the ANDRILL AND-2A borehole, providing ages on the timing of major ice stream advances of the East Antarctic Ice Sheet in the western Ross Sea area.

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

2010-12-01

21

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

NASA Astrophysics Data System (ADS)

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

Dias-Brito, D.; Ferré, B.

2001-06-01

22

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

23

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

Microsoft Academic Search

The BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well was an integral part of an ongoing project to determine the future energy resource potential of gas hydrates on the Alaska North Slope. As part of this effort, the Mount Elbert well included an advanced downhole geophysical logging program. Because gas hydrate is unstable at ground surface pressure and temperature conditions,

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

2011-01-01

24

Stratigraphic modeling of sedimentary basins  

SciTech Connect

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

Aigner, T. (Shell Research B. V., Rijswijk (Netherlands)); Lawrence, D.T. (Shell Development Co., Houston, TX (USA))

1990-11-01

25

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

Microsoft Academic Search

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

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

2011-01-01

26

Quantification and modelling of the distorsion of the stratigraphic architecture of the syn-sedimentary infill of a normal fault (offshore Congo)  

Microsoft Academic Search

We characterized the influence of a normal growth fault upon the stratigraphic architecture of the syn-sedimentary infill, in the case of a structure located along the West African margin, in terms of (1) variations in time and space of the accommodation (space available for sedimentation) and (2) distorsion of the geometry and timing of depositional sequences. To achieve this with

C. Robin; D. Rouby; F. Guillocheau; D. Granjeon; R. Bouroullec; S. Raillard

2003-01-01

27

A nondestructive test contribution to the safety of offshore cranes  

SciTech Connect

Non-Destructive Testing (NDT) plays a vital role in safety as well as in economics of manufacturing. This paper shows an example of how NDT has been successfully used offshore in Europe for a number of years, inspecting slewing bearings. Slewing bearings are the bearings that support among other things cranes and earth-moving equipment. These bearings carry a very heavy slow moving unbalanced axial-load. Due to the extreme environment and the very heavy and unbalanced loading supported by the bearings, particularly on oil exploration and production platforms in the North Sea, some bearings have failed catastrophically. In order to minimize the dangers, authorities have stipulated that slewing bearings for cranes employed in the North Sea are to be periodically inspected. The normal life-restricting failure mode of slewing bearings is spalling of the raceways. This is the rolling contact surface of the bearing breaking-up under the very heavy loads imposed upon it. The developed ultrasonic testing technique, apart from detecting and monitoring cracks in the stressed areas of the bearing, is also able to monitor the initiation and growth of any spalling on the main raceways of the bearings, thus enabling better planning on maintenance and replacements. This paper describes the development of the ultrasonic testing system.

Hands, G. [MEAGH, Nieuwegein (Netherlands); Bourgeors-Jacquet, P. [SKF RKS SA, Avallon (France)

1995-10-01

28

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

29

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

USGS Publications Warehouse

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

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

2011-01-01

30

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

E-print Network

Meren field, located offshore Niger Delta, is one of the most prolific oil-producing fields in the Niger Delta. The upper Miocene D-07, D-08 and E-01 oil sands comprise a series of stacked hydrocarbon reservoirs in Block 2 of Meren field...

Esan, Adegbenga Oluwafemi

2004-09-30

31

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

32

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

SciTech Connect

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

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

1996-12-31

33

Materials, manufacturing and testing requirements for offshore mooring steel wire ropes  

SciTech Connect

The trend to produce oil at constantly deeper water has led to the development of floating production solutions for the exploitation of the energy resources in these areas. It is a fact that steel wire ropes have been used and are being proposed for use as line segments in the majority of the mooring systems of these units/ships. This paper specifies requirements for the materials, design, manufacture and testing of large diameter offshore mooring steel wire ropes and may serve as a technical reference document in contractual matters between the purchaser and the manufacturer. Typical applications covered are permanent moored floating production systems (FPS), offshore loading systems and mobile offshore units.

Lohne, P.W.

1996-12-31

34

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

35

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...

36

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

37

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

38

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

39

Grid Simulator for Testing a Wind Turbine on Offshore Floating Platform  

SciTech Connect

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

Gevorgian, V.

2012-02-01

40

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

Microsoft Academic Search

Using cryogenic scanning electron microscopy (CSEM), powder X-ray diffraction, and gas chromatography methods, we investigated the physical states, grain characteristics, gas composition, and methane isotopic composition of two gas-hydrate-bearing sections of core recovered from the BPXA–DOE–USGS Mount Elbert Gas Hydrate Stratigraphic Test Well situated on the Alaska North Slope. The well was continuously cored from 606.5m to 760.1m depth, and

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

2011-01-01

41

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

Microsoft Academic Search

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

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

2011-01-01

42

Baltimore Canyon Trough Mesozoic Carbonate Margin Cores, Offshore USA Atlantic  

Microsoft Academic Search

In 1984 three wells operated by Shell tested various types of Jurassic-Cretaceous carbonate shelf and margin plays in deep water offshore New Jersey. Eleven cores were recovered: OCS-A 0336 cores R1-4, OCS-A 0337 cores C1-3 and OCS-A 0317 cores H1-4. Representative core intervals on display are keyed to seismic morphology and show litho- biofacies from three geometrically and stratigraphically separate

Leslie S. Eliuk

43

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

USGS Publications Warehouse

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

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

2011-01-01

44

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

45

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

46

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

47

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

SciTech Connect

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

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

2013-07-01

48

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

49

Supercapacitor testing for power smoothing in a variable speed offshore Wave Energy Converter  

Microsoft Academic Search

This paper investigates power smoothing in a full-scale offshore Oscillating Water Column (OWC) Wave Energy Converter (WEC) by integrating supercapacitors (SCs) with the inertia of a Wells turbine controlled at variable speed. A Simulink model is developed for the WEC system utilising sea state data and a SC system is sized to smooth and reduce the grid peak power for

Donal B. Murray; J. G. Hayes; M. G. Egan; D. L. O'Sullivan

2011-01-01

50

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

SciTech Connect

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

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

2011-06-01

51

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

52

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

53

Tectonic-stratigraphic division and blind fold structures in Nansha Waters, South China Sea  

Microsoft Academic Search

Extensive multiple-channel reflection seismic data have been collected in the Nansha (Spratley Islands) Waters, the southern margin of the South China Sea. Stratigraphic correlation is shown with focus on a comprehensive geophysiXcal survey line run from offshore NW Sabah to offshore SE Vietnam. According to the varying tectono-stratigraphy from southeast to northwest, five tectonic belts can be determined, i.e. the

Pin Yan; Hailing Liu

2004-01-01

54

Offshore Technology  

NSDL National Science Digital Library

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

55

Offshore medicine.  

PubMed

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

Baker, D

2001-03-01

56

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

57

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

SciTech Connect

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

Musial, W.

2014-08-01

58

Titanium offers offshore advantages  

SciTech Connect

Titanium is slowly becoming the answer to many of the corrosion problems associated with offshore drilling and sour hydrocarbons. The possible implications of titanium's resistance to hypochlorite solutions is still under study. Various tests have been run on this and its alloys. A growing number of applications will also take advantage of the strength to weight ratio of titanium.

Gilbert, R.

1984-04-01

59

Stratigraphic Architecture of Table Rock, Boise, Idaho  

NSDL National Science Digital Library

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

Matson, Sam

60

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

61

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

62

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

NASA Astrophysics Data System (ADS)

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

Tabibzadeh, Maryam

63

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

64

Stratigraphic Units in Las Vegas Valley, Nevada  

NASA Astrophysics Data System (ADS)

Using 25 well logs, 15 of which also had accompanying geophysical and aquifer test data were used to describe and establish three alloformations including the Tule Spring and Paradise Valley Alloformations and four aquiformations, the most well defined being, the Las Vegas Springs Aquiformation, in the west central part of the bolson (Donovan, 1996), primarily in Township 20 South, Range 60 East, Mount Diablo Baseline and Meridian (MDBLM), with the stratotypes designated in T20S, R61E S31 MDBLM (36° 9'59.89"N 115°11'26.34"W). The allostratigraphic units were developed using the recommendations in the North American Code of Stratigraphic Nomenclature (NACSN, 1983 and 2005). The hydrostratigraphic units were developed following the recommendations of Seaber (1992). The units constitute the bulk of the upper 500 meter section. Twenty additional wells in the same geographic area, drilled and completed between 1995 and 2005 with detailed geologic and hydrologic information provided confirmation of these units. The proposed stratigraphic units are not part of either, and are located between, the two previously named and non-contiguous formations in the bolson (the Miocene Muddy Creek Formation and the late Pleistocene Las Vegas Formation) (Longwell et al 1965). Las Vegas Valley contains a metropolitan area of approximately two million people. The deeper part of the alluvial basin below 300 ft below ground surface is of interest for supply and storage. The shallower part is of interest for water quality and the interaction between the ground water system and engineered structures.

Donovan, D.

2013-12-01

65

Experimental investigation of gas-water relative permeability for gas-hydrate-bearing sediments from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope  

Microsoft Academic Search

Permeability of hydrate reservoirs found in nature is likely to be heavily influenced by the percent of the pore volume occupied by hydrates. The quantification of how hydrate saturation affects permeability is of key interest for reservoir engineering studies. In this study, an experimental setup was modified to test permeability characteristics of unconsolidated core samples containing various saturations of methane

Andrew Johnson; Shirish Patil; Abhijit Dandekar

2011-01-01

66

Testing alternative tectono-stratigraphic interpretations of the Late Palaeozoic-Early Mesozoic Karakaya Complex in NW Turkey: support for an accretionary origin related to northward subduction of Palaeotethys  

NASA Astrophysics Data System (ADS)

The mainly Permian-Triassic rocks of the Karakaya Complex exposed E-W across Turkey are critical to reconstruction of Tethys in the E Mediterranean region. Their origin remains controversial with both stratigraphic layer-cake and accretionary-type settings being advocated. Suggested tectonic settings range from back-arc rift, to accretionary prism- related to either northward or southward subduction. To test alternatives we have studied the contact relations and the internal fabric of each of the main litho-tectonic units making up the Karakaya Complex and related "basement" in nine outcrop areas across NW Turkey, also taking account of existing chemical and dating evidence. Our results show that the Karakaya Complex was assembled by regional-scale thrust faulting without evidence of layer cake-type stratigraphical contacts, or even of deformed sedimentary contacts separating the major lithotectonic units. In several areas (e.g. Havran) the outcrops of meta-siliciclastic sediments of presumed Palaeozoic-age (~Kalabak Unit) are locally cut by Early-Mid Devonian granites. These outcrops represent one or more high-level crustal imbricates made up of basement rocks together with depositionally overlying U. Triassic siliciclastic rocks. Evidence from structurally lower, high pressure-low temperature Karakaya rocks (~Nilüfer Unit) reveals an imbricated, mainly volcaniclastic-carbonate sequence. Both these relatively high-grade Karakaya rocks and the structurally overlying, lower-grade Karakaya rocks (i.e. Çal and Ortaoba units) are interpreted as tectonically emplaced accretionary melange rather than sedimentary "olistostromes". MOR-type basalts (Ortaoba Unit) are locally overlain by red ribbon radiolarites that then pass upwards into feldspar-rich siliciclastics. Triassic oceanic crust and oceanic siliceous sediments were overlain by terrigenous turbidites derived from the north (Sakarya continent), followed by tectonic accretion at a subduction trench bordering the southern margin of Eurasia. Other volcanic units (~Çal and ~Nilüfer) are of typical within-plate type, characteristic of seamount or rift settings but outside the range of compositions of Large Igneous Province (LIP) magmatic rocks. The ~Nilüfer Unit is interpreted as mainly the flanking facies of Triassic intra-oceanic volcanic seamounts; this material preferentially accreted, whereas the seamount core material mainly subducted. In contrast, the traditional Çal Unit is subdivided into two (related) parts. One part reflects U. Permian rifting, probably of the Tauride continental margin to the south, as suggested by the widespread presence of terrigenous sediments stratigraphically beneath U. Permian platform carbonates. The other part (type Çal) records intra-plate-type volcanism, probably as marginal seamounts within adjacent oceanic crust. In our tectonic model, the Karakaya Complex relates to Triassic northward subduction of Palaeotethys (Late Palaeozoic?), while Triassic oceanic crust simultaneously formed adjacent to Gondwana (~Tauride continent). Older Palaeotethyan oceanic crust subducted northwards beneath the S Eurasian margin, represented by Peri-Gondwanan terrane(s) (e.g. Central Sakarya basement) that accreted to Eurasia prior to late Carboniferous time. Upper Permian neritic carbonates and volcanics relate to rifting of the Tauride continent to the south (~Çal Unit). Large (plume-related?) oceanic seamounts (~Nilüfer Unit) erupted within the Triassic ocean. The seamounts and rifted continental fragment(s) drifted northwards across remnant Palaeotethys and accreted to the southern, active margin of Eurasia, represented by the Sakarya basement. The Karakaya accretionary prism was finally obducted northwards over U. Triassic deltaic to deeper-marine cover sediments of the Sakarya basement during latest Triassic (Norian) time, culminating in crustal-scale intercalation of accretionary and basement/cover material. The probable cause was collision of one, or several, large oceanic seamounts. This model is broadly applicable for

Robertson, Alastair; Ustaömer, Timur

2010-05-01

67

Sequence-Stratigraphic Analysis of the Regional Observation Monitoring Program (ROMP) 29A Test Corehole and Its Relation to Carbonate Porosity and Regional Transmissivity in the Floridan Aquifer System, Highlands County, Florida  

USGS Publications Warehouse

An analysis was made to describe and interpret the lithology of a part of the Upper Floridan aquifer penetrated by the Regional Observation Monitoring Program (ROMP) 29A test corehole in Highlands County, Florida. This information was integrated into a one-dimensional hydrostratigraphic model that delineates candidate flow zones and confining units in the context of sequence stratigraphy. Results from this test corehole will serve as a starting point to build a robust three-dimensional sequence-stratigraphic framework of the Floridan aquifer system. The ROMP 29A test corehole penetrated the Avon Park Formation, Ocala Limestone, Suwannee Limestone, and Hawthorn Group of middle Eocene to Pliocene age. The part of the Avon Park Formation penetrated in the ROMP 29A test corehole contains two composite depositional sequences. A transgressive systems tract and a highstand systems tract were interpreted for the upper composite sequence; however, only a highstand systems tract was interpreted for the lower composite sequence of the deeper Avon Park stratigraphic section. The composite depositional sequences are composed of at least five high-frequency depositional sequences. These sequences contain high-frequency cycle sets that are an amalgamation of vertically stacked high-frequency cycles. Three types of high-frequency cycles have been identified in the Avon Park Formation: peritidal, shallow subtidal, and deeper subtidal high-frequency cycles. The vertical distribution of carbonate-rock diffuse flow zones within the Avon Park Formation is heterogeneous. Porous vuggy intervals are less than 10 feet, and most are much thinner. The volumetric arrangement of the diffuse flow zones shows that most occur in the highstand systems tract of the lower composite sequence of the Avon Park Formation as compared to the upper composite sequence, which contains both a backstepping transgressive systems tract and a prograding highstand systems tract. Although the porous and permeable layers are not thick, some intervals may exhibit lateral continuity because of their deposition on a broad low-relief ramp. A thick interval of thin vuggy zones and open faults forms thin conduit flow zones mixed with relatively thicker carbonate-rock diffuse flow zones between a depth of 1,070 and 1,244 feet below land surface (bottom of the test corehole). This interval is the most transmissive part of the Avon Park Formation penetrated in the ROMP 29A test corehole and is included in the highstand systems tract of the lower composite sequence. The Ocala Limestone is considered to be a semiconfining unit and contains three depositional sequences penetrated by the ROMP 29A test corehole. Deposited within deeper subtidal depositional cycles, no zones of enhanced porosity and permeability are expected in the Ocala Limestone. A thin erosional remnant of the shallow marine Suwannee Limestone overlies the Ocala Limestone, and permeability seems to be comparatively low because moldic porosity is poorly connected. Rocks that comprise the lower Hawthorn Group, Suwannee Limestone, and Ocala Limestone form a permeable upper zone of the Upper Floridan aquifer, and rocks of the lower Ocala Limestone and Avon Park Formation form a permeable lower zone of the Upper Floridan aquifer. On the basis of a preliminary analysis of transmissivity estimates for wells located north of Lake Okeechobee, spatial relations among groups of relatively high and low transmissivity values within the upper zone are evident. Upper zone transmissivity is generally less than 10,000 feet squared per day in areas located south of a line that extends through Charlotte, Sarasota, DeSoto, Highlands, Polk, Osceola, Okeechobee, and St. Lucie Counties. Transmissivity patterns within the lower zone of the Avon Park Formation cannot be regionally assessed because insufficient data over a wide areal extent have not been compiled.

Ward, W. C.; Cunningham, K.J.; Renken, R.A.; Wacker, M.A.; Carlson, J.I.

2003-01-01

68

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

69

Stratigraphic correlation for the IODP Expedition 347 - toward an integrated Baltic Sea Basin stratigraphy  

NASA Astrophysics Data System (ADS)

The IODP Expedition 347 - "Baltic Sea Paleoenvironment" completed in September - November 2013 (offshore phase) was the 5th and the final mission-specific platform (MSP) expedition of the Integrated Ocean Drilling Program. The expedition used a geotechnical drillship, the Greatship Manisha equipped with a Geoquip Marine coring rig, to core and wireline-log several sub-basins within the Baltic Sea, aiming to produce new information on the history of the Baltic Sea and climate change during the last glacial cycle. During the IODP Expedition 347 altogether over 1900 meters were successfully drilled at 8 Sites (M0059 - M0067) in the Lille Belt, Kattegat, Ångermanälven Estuary, Landsort Deep, Hanö Basin and Bornholm Basin with core recovery of approximately 1600 m (expansion adjusted core recovery of 91.46%). In this presentation, we show the preliminary results of regional stratigraphic correlation and splice results for the Expedition. That information provides a solid base for stratigraphic and high-resolution paleoenvironmental studies. Stratigraphic correlation consisted of the following: (1) ensuring the maximum core recovery on site, (2) seismic-core (sedimentary facies) correlation and (3) generating composite depth scales and splice records to each site. To obtain a complete sedimentary record, multiple adjacent holes were cored with an offset in depth of 0.5-1.5 m between cores from different holes. The continuity of recovery was assessed by generating composite sections that align prominent features in physical property data from adjacent holes. With the information gained by Fast Track Multi-Sensor Core Logger (MSCL) data, it was possible to adjust coring plan before the new hole, to ensure that intervals missing in previous cores could be recovered from an adjacent hole. Correlation between seismic profiles and cores used a simple estimation sound velocity vs. sediment type. Acquired depth was tested by comparison with major core surfaces, downhole logs, and the MSCL data (density and magnetic susceptibility). This data integration required preliminary interpretation of sedimentary units and comparisons with physical property boundaries. To align similar features in physical (geological) properties between different holes (or even different sites), MSCL physical property measurements were correlated (using Correlator software), to create a composite depth (mcd) scale. Splice records were generated by selecting sections from adjacent holes to avoid core gaps or disturbed sediment, resulting in a continuous record. This formed the basis for onshore sediment sampling and post-cruise research.

Kotilainen, Aarno; Hyttinen, Outi; Andrén, Thomas; Cotterill, Carol; Hale, Walter; IODP Expedition 347 Science Party, the

2014-05-01

70

Drilling tools for continuous offshore operations  

SciTech Connect

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

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

1995-12-31

71

Application of TIMS data in stratigraphic analysis  

NASA Technical Reports Server (NTRS)

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

Lang, H. R.

1986-01-01

72

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

73

Stratigraphically consistent autointerpretation of borehole data  

NASA Astrophysics Data System (ADS)

Many techniques exist for computer-aided interpretation of geological, geotechnical, and resource quality parameters from downhole geophysical data. Usually the measurements at any one depth are interpreted without regard to the data at other depths. However, in some circumstances, it is desirable to generate interpretations that conform to a known stratigraphic succession. Accordingly, this paper describes progress towards the development of an a posteriori stratigraphic correction procedure. The correction procedure operates on a preexisting interpretation of stratigraphic units based on their wireline signatures alone. The inputs are the stratigraphic order itself, and minimum, maximum, and standard (average) thicknesses defined for each of the stratigraphic units. Correction is effected in three stages, targeting successively (a) layers that exceed the minimum thickness, (b) thin layers, and (c) excessively thick layers. During each stage, a directed trial-and-error process resolves stratigraphic conflicts between adjacent layers. The process is expedited if a petrophysically distinct "marker bed" occurs in the sequence. The correction algorithm has been illustrated in the context of geotechnical modelling at the German Creek coal mine, Queensland. Results achieved to date have been sufficiently encouraging to warrant a trial implementation of computer-aided geotechnical interpretation at the mine.

Fullagar, Peter K.; Zhou, Binzhong; Biggs, Mark

2004-01-01

74

Time lapse survey plan on the first offshore methane hydrate production test in 2013 around the eastern Nankai Trough area by multi-component OBC seismic tool  

NASA Astrophysics Data System (ADS)

We are planning to conduct the multi-component ocean bottom cable (hereafter OBC) seismic survey to monitor the methane hydrate dissociation zone at the 1st offshore methane hydrate production test site in the eastern Nankai Trough, Japan, in 2013. We conducted the first OBC survey in the methane hydrate concentrated zone around the eastern Nankai Trough area in 2006 by RSCS which we developed. We obtained to the good image of methane hydrate bearing layer by P-P section as similar as the conventional surface seismic survey. However, we could not obtain the good image from P-S section compared with P-P section. On the other hand, we studied the sonic velocity distribution at the Mallik 2nd production test before and after in 2007, by the sonic tool data. We could clearly delineate the decrease of S-wave velocity, however, we could not detect the decrease of P-wave velocity because of the presence of the dissociated methane gas from methane hydrate. From these reason we guess the S-wave data is more proper to delineate the condition of the methane hydrate zone at the methane hydrate production tests than P-wave data. We are now developing the new OBC system, which we call Deep-sea Seismic System (hereafter DSS). The sensor of the DSS will install three accelerometers and one hydrophone. A feasibility study to detect the methane hydrate dissociation with the DSS was carried out and we found that the methane hydrate dissociation could be detected with the DSS depending on the zone of the dissociation. And the baseline survey will be held at the 1st offshore methane hydrate production test site in summer 2012. Two monitoring surveys are planned after the methane hydrate production test in 2013. We believe that we will get the good images to delineate the methane hydrate dissociated zone from this time lapse survey. The Authors would like to thank METI, MH21 consortium and JOGMEC for permissions to publish this paper.

Inamori, T.; Hayashi, T.; Asakawa, E.; Takahashi, H.; Saeki, T.

2011-12-01

75

Offshore Wind Geoff Sharples  

E-print Network

Offshore Wind Geoff Sharples geoff@clearpathenergyllc.com #12;Frequently Unanswered Ques?ons · Why don't "they" build more offshore wind? · Why not make States Cape Wind PPA at 18 c/kWh #12;The cycle of non-innova?on Offshore

Kammen, Daniel M.

76

CONGRESSIONAL BRIEFING Offshore Wind  

E-print Network

CONGRESSIONAL BRIEFING Offshore Wind Lessons Learned from Europe: Reducing Costs and Creating Jobs Thursday, June 12, 2014 Capitol Visitors Center, Room SVC 215 Enough offshore wind capacity to power six the past decade. What has Europe learned that is applicable to a U.S. effort to deploy offshore wind off

Firestone, Jeremy

77

Underbalanced drilling benefits now available offshore  

SciTech Connect

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

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

1997-05-01

78

Offshore oil prospects improve  

NASA Astrophysics Data System (ADS)

The issues, prospects, and environmental concerns about drilling for offshore oil and gas are being seen in a different light than at any other time during the past decade. Exploration drilling on offshore locations is proceeding at a high rate, and environmental concerns, while recognized as real, appear to be a lot less worrisome than might have been predicted a decade ago. Part of the reason for the changes in levels of concern results from the close monitoring programs that have been in effect for the past few years. Paul R. Ryan of the Woods Hole Oceanographic Institution recently described exploration activities on Georges Bank: “We now have the results of the first year of monitoring, and, although eight wells are considered a minimal observational test, there were no biological changes in the benthic community that could be attributed to drilling activity.” (Oceanus, 26, 2, 1983). The U.S. Geological Survey studied the Georges Bank drilling activities as well. Barium from drilling muds was detected at the sites, but in decreasing concentrations at distances away from drilling rigs. There was no evidence that the discharges caused biological changes. According to Ryan: “Postdrilling concentrates of barium were found to be within the range of predilling concentrations measured at other locations on the Bank. Concentrations of other metals measured were low and characteristic of unpolluted, coarse-grained sediment in other Continental Shelf areas.”

79

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

Microsoft Academic Search

A hydrodynamic model is described to account for oil and gas occurrences in the Cretaceous of offshore Qatar, in the Arabian Gulf. Variable and inconsistent fluid levels and variable formation water potentials and salinities cannot be explained by combinations of stratigraphic and structural trapping. Indeed, there is no structural closure to the southwest of the oil and gas accumulations. The

1988-01-01

80

Some debatable problems of stratigraphic classification  

NASA Astrophysics Data System (ADS)

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

Gladenkov, Yury

2014-05-01

81

Fault-zone seals in offshore Trinidad oil fields  

SciTech Connect

Hydrocarbon columns in Pliocene sands of offshore SE Trinidad occur in 3-way closure, primarily in the footwall of normal faults. Multiple reservoir sands and numerous fault blocks result in a large number of individual hydrocarbon accumulations. Fault-plane sections demonstrate that fault sealing is unrelated to juxtaposition of intercalated shales. These fault-zone capillary seals were studied by (1) inferring their fluid-flow properties from the pattern of trapped hydrocarbons and (2) direct examination and measurement of cored faults. Buoyancy pressures for hydrocarbon columns were calculated from fluid property data for each reservoir and fault block. Buoyancy pressures range widely, increasing nonlinearly with fault displacement and percent shale in the faulted section, but do not vary systematically with stratigraphic position or depth. Small-displacement faults observed in core are narrow zones of cataclasis within porous sandstone. Mercury injection tests indicate fault-zone displacement pressures that coincide with buoyancy pressures calculated for hydrocarbon columns sealed by large-displacement faults. The agreement between measured displacement pressures and calculated buoyancy pressures indicates that (1) the reservoirs are filled to their capacity, dictated by the displacement pressure of the fault zones, and (2) the fault-zone seals are primarily the product of deformation of the sands, with some enhancement by incorporation of argillaceous material into the fault zones. The observed relationship between fault displacement and calculated buoyancy pressure of the hydrocarbon columns implies that fault-zone continuity is a factor that needs to be assessed in fault-zone seal analysis.

Gibson, R.G. (Amoco Research Center, Tulsa, OK (United States))

1991-03-01

82

Certification of offshore mooring steel wire ropes  

SciTech Connect

The trend to produce oil in increasingly deeper water has led to the development of floating production solutions for the exploitation of the energy resources in these areas. It is a fact that steel wire ropes have been used and are being proposed as line segments in the majority of the mooring systems of these units/ships. This paper specifies requirements for the materials, design, manufacture and testing of large diameter offshore mooring steel wire ropes and may serve as a technical reference document in contractual matters between the purchaser and the manufacturer. Typical applications covered are permanently moored floating production systems (FPS), offshore loading systems and mobile offshore units.

Lohne, P.W. [Det Norske Veritas AS, Oslo (Norway)

1996-12-31

83

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

84

Stratigraphic Columns Across Southern Western Interior  

NSDL National Science Digital Library

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

Blakey, Ronald

85

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

NASA Astrophysics Data System (ADS)

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

Yamamoto, K.; Fujii, T.

2013-12-01

86

Rubber in offshore engineering  

Microsoft Academic Search

The offshore oil and gas industries have been turning increasingly to natural and synthetic rubbers for a very wide variety of uses, since they are flexible and highly corrosion-resistant in hostile marine environments, and exhibit predictable and reproducible behaviour under a wide range of physical conditions. This book considers the growing popularity of rubber as an offshore material, providing a

Stevenson

1984-01-01

87

Offshore Renewable Energy Solutions  

E-print Network

and maximising energy extraction. Offshore understanding Our long track record working with the oil and gasOffshore Renewable Energy Solutions #12;Cefas: meeting complex requirements The Centre and fisheries data. We also work collaboratively, with cross-cutting project teams, innovators in the supply

88

MODELLING THE VERTICAL WIND SPEED AND TURBULENCE INTENSITY PROFILES AT PROSPECTIVE OFFSHORE WIND FARM SITES  

E-print Network

MODELLING THE VERTICAL WIND SPEED AND TURBULENCE INTENSITY PROFILES AT PROSPECTIVE OFFSHORE WIND important for offshore wind energy utilisation are discussed and tested: Four models for the surface tested with data from the offshore field measurement Rødsand by extrapolating the measured 10 m wind

Heinemann, Detlev

89

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES  

E-print Network

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES important for offshore wind energy utilisation are discussed and tested: Four models for the surface tested with data from the offshore field measurement Rødsand by extrapolating the measured 10 m wind

Heinemann, Detlev

90

MODELLING THE VERTICAL WIND SPEED AND TURBULENCE INTENSITY PROFILES AT PROSPECTIVE OFFSHORE WIND FARM SITES  

E-print Network

MODELLING THE VERTICAL WIND SPEED AND TURBULENCE INTENSITY PROFILES AT PROSPECTIVE OFFSHORE WIND for conditions important for offshore wind energy utilisation are compared and tested: Four models tested with data from the offshore field measurement Rødsand by extrapolating the measured 10 m wind

Heinemann, Detlev

91

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

92

Preliminary Stratigraphic Basis for Geologic Mapping of Venus  

NASA Technical Reports Server (NTRS)

The age relations between geologic formations have been studied at 36 1000x1000 km areas centered at the dark paraboloid craters. The geologic setting in all these sites could be characterized using only 16 types of features and terrains (units). These units form a basic stratigraphic sequence (from older to younger: (1) Tessera (Tt); (2-3) Densely fractured terrains associated with coronae (COdf) and in the form of remnants among plains (Pdf); (4) Fractured and ridged plains (Pfr); (5) Plains with wrinkle ridges (Pwr); (6-7) Smooth and lobate plains (Ps/Pl); and (8) Rift-associated fractures (Fra). The stratigraphic position of the other units is determined by their relation with the units of the basic sequence: (9) Ridge bells (RB), contemporary with Pfr; (10-11) Ridges of coronae and arachnoids annuli (COar/Aar), contemporary with wrinkle ridges of Pwr; (12) Fractures of coronae annuli (COaf) disrupt Pwr and Ps/Pl; (13) Fractures (F) disrupt Pwr or younger units; (14) Craters with associated dark paraboloids (Cdp), which are on top of all volcanic and tectonic units except the youngest episodes of rift-associated fracturing and volcanism; (15-16) Surficial streaks (Ss) and surficial patches (Sp) are approximately contemporary with Cdp. These units may be used as a tentative basis for the geologic mapping of Venus including VMAP. This mapping should test the stratigraphy and answer the question of whether this stratigraphic sequence corresponds to geologic events which were generally synchronous all around the planet or whether the sequence is simply a typical sequence of events which occurred in different places at diffferent times.

Basilevsky, A. T.; Head, J. W.

1993-01-01

93

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.

94

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

Microsoft Academic Search

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

Jun Li; Thomas Servais; Kui Yan; Huaicheng Zhu

2004-01-01

95

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

96

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

97

Application of sequence and genetic stratigraphic concepts to Carboniferous coal-bearing strata: an example from the Black Warrior basin, USA  

Microsoft Academic Search

Carboniferous strata provide an excellent example on which to test the application of genetic stratigraphic and sequence stratigraphic concepts. Both approaches are employed in the evaluation of the coal-bearing strata of the Black Warrior basin, south-eastern USA. Bounding hiatal surfaces have been recognized in the succession of rock that includes the Mary Lee coal zone. Within the framework of genetic

Robert A. Gastaldo; Timothy M. Demko; Yuejin Liu

1993-01-01

98

Selected stratigraphic contacts for drill holes in LANL use areas of Yucca Flat, NTS  

Microsoft Academic Search

This report is a compilation of selected stratigraphic contacts in drill holes of Yucca Flat, Nevada Test Site (NTS), used by the Los Alamos National Laboratory (LANL). This is the product of an ongoing effort to establish and maintain the most up-to-date database of formation tops in LANL use areas of Yucca Flat. Figure 1 is an index map showing

Drellack; S. L. Jr

1988-01-01

99

3D Stratigraphic Modeling of Central Aachen  

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

100

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES  

E-print Network

EVALUATION OF MODELS FOR THE VERTICAL EXTRAPOLATION OF WIND SPEED MEASUREMENTS AT OFFSHORE SITES important for offshore wind energy utilisation are discussed and tested: Four models for the surface that an important part of the future expansion of wind energy utilisation at least in Europe will come from offshore

Heinemann, Detlev

101

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

Microsoft Academic Search

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

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

1996-01-01

102

Hydrocarbon exploration evaluation of Pulley Ridge area, offshore south Florida basin  

SciTech Connect

The results of an extensive geologic and geophysical evaluation of the Pulley Ridge area in the offshore South Florida basin, eastern Gulf of Mexico, indicate that this area contains all critical factors needed for considerable hydrocarbon accumulations to develop. Geologic well evaluation, both onshore and offshore, confirms the presence of at least four viable potential carbonate reservoir units in the Lower Cretaceous section. Organically rich oil-prone carbonate rocks are found in several Lower Cretaceous stratigraphic intervals between the Bone Island formation and the Dollar Bay Formation. In addition, extensively developed trapping seals consisting of micritic limestones and anhydrites are common in the stratigraphic section. Using state-of-the-art marine seismic data for the Pulley Ridge area, additional geophysical and geologic evaluation of the lead areas already identified could result in discovering significant hydrocarbon reserves in this shallow-water, sparsely drilled carbonate basin oil play.

Faulkner, B.M.; Applegate, A.V.

1986-09-01

103

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

NASA Astrophysics Data System (ADS)

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

Abdel-Fattah, Mohamed I.; Slatt, Roger M.

2013-12-01

104

Are Offshoring and Immigration Substitutes for Canada?  

Microsoft Academic Search

SUMMARY NDUSTRY CANADA ORIGINALLY PROPOSED the question in the title as the basis for a research paper. Because of the lack of data suitable for framing and testing a quantitative model, the resulting paper instead provides some tentative estimates of the relative sizes of immigration and offshoring in the Canadian context, specifically in the context of skilled services. Very approximate

John F. Helliwell

105

High-Alloy Materials for Offshore Applications  

Microsoft Academic Search

High-alloy materials possessing good corrosion resistance in hot, sour brines are being seriously considered for offshore applications. These alloys are available in a wide range of strength levels which can be attained by the methods of cold working or precipitation hardening. Results of testing INCONEL alloys 625 and 718 and INCOLOY alloys 825 and 925 for resistance to general corrosion,

T. F. Lemke; J. A. Harris

1983-01-01

106

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

107

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

108

Lake Michigan Offshore Wind Feasibility Assessment  

SciTech Connect

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

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

2014-06-30

109

Tectonic-stratigraphic division and blind fold structures in Nansha Waters, South China Sea  

NASA Astrophysics Data System (ADS)

Extensive multiple-channel reflection seismic data have been collected in the Nansha (Spratley Islands) Waters, the southern margin of the South China Sea. Stratigraphic correlation is shown with focus on a comprehensive geophysiXcal survey line run from offshore NW Sabah to offshore SE Vietnam. According to the varying tectono-stratigraphy from southeast to northwest, five tectonic belts can be determined, i.e. the Palawan-Borneo Nappe, Nansha Trough, Nanwei-Liyue Compressive Belt, Zheng'he Extensional Belt and the Circum-Southwest Subbasin Belt. In the Palawan-Borneo Nappe, Neogene-Quaternary deposits were highly upthrust northwestwards, resulting in a series of moderately to tightly folded anticlines separated by open synclines. The Nansha Trough was a narrow, deep-water belt filled with thick, undisturbed Neogene-Quaternary deposits. The Nanwei-Liyue Compressive Belt was dominated by strongly folded paleo-anticlines overlain by an undeformed sedimentary cap with a pronounced hiatus of Paleogene sediments. The Zheng'he Extensional Belt consisted of a rugged topography and Paleogene half-grabens bounded by listic faults. The major extensional faults were reactivated to cut through the overlying Neogene-Quaternary deposits. Over the Circum-Southwest Subbasin Belt, Neogene-Quaternary deposits draped on the largely subsided fault blocks related to the Late Oligocene-Mid-Miocene seafloor spreading. Based on the regional stratigraphic correlation, the prominent paleo-anticlines found within the Nanwei-Liyue Compressive Belt are deduced to consist of mainly Mesozoic marine sediments that were compressed in the Late Mesozoic Era. Therefore, the Nansha Microcontinent Block is shown to be a collision complex assembled during Late Mesozoic Era.

Yan, Pin; Liu, Hailing

2004-12-01

110

California offshore wind energy potential  

Microsoft Academic Search

This study combines multi-year mesoscale modeling results, validated using offshore buoys with high-resolution bathymetry to create a wind energy resource assessment for offshore California (CA). The siting of an offshore wind farm is limited by water depth, with shallow water being generally preferable economically. Acceptable depths for offshore wind farms are divided into three categories: ?20m depth for monopile turbine

Michael J. Dvorak; Cristina L. Archer; Mark Z. Jacobson

2010-01-01

111

Kentish Flats Offshore Wind Farm  

E-print Network

Kentish Flats Offshore Wind Farm #12;By August 2005 the offshore wind farm at Kentish Flats and offshore wind energy will contribute sig- nificantly to achieving this target. The Kentish Flats alone plateau just outside the main Thames shipping lanes. The Kentish Flats wind farm will comprise 30

Firestone, Jeremy

112

The geotechnical centrifuge in offshore engineering  

SciTech Connect

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

Murff, J.D.

1996-12-31

113

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

114

Offshore Wind Energy Systems  

ERIC Educational Resources Information Center

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

Musgrove, P.

1978-01-01

115

Selected stratigraphic contacts for drill holes in LANL use areas of Yucca Flat, NTS  

SciTech Connect

This report is a compilation of selected stratigraphic contacts in drill holes of Yucca Flat, Nevada Test Site (NTS), used by the Los Alamos National Laboratory (LANL). This is the product of an ongoing effort to establish and maintain the most up-to-date database of formation tops in LANL use areas of Yucca Flat. Figure 1 is an index map showing areas of the NTS covered in this report. A drill hole planning map showing hole locations is in the rear pocket. Data presented for each drill hole include drill hole name; year drill hole completed; ground level elevations, above mean sea level (MSL), at drill hole site; total depth (TD) of drill hole at completion of drilling; and depth below surface to selected stratigraphic contacts. The geologic data presented here was generated by numerous individuals. Published references, from which most of these data originated, are listed on page 54 of this report. Information regarding other drill hole statistics can be found in the NTS Drilling and Mining Summary (``The Redbook``) compiled by the Technical Support Division of Fenix and Scisson, Inc. We continue the ``revised`` stratigraphic nomenclature for the bedded tuffs between the Rainier Mesa Member of the Timber Mountain Tuff and the Grouse Canyon Member of the Belted Range Tuff (formerly the ``Paintbrush Tuff``). Confidence in these stratigraphic assignments for these bedded tuffs is consolidating. 13 refs., 4 figs., 2 tabs.

Drellack, S.L. Jr.

1988-07-01

116

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

117

Probabilistic sequence alignment of stratigraphic records  

NASA Astrophysics Data System (ADS)

assessment of age uncertainty in stratigraphically aligned records is a pressing need in paleoceanographic research. The alignment of ocean sediment cores is used to develop mutually consistent age models for climate proxies and is often based on the ?18O of calcite from benthic foraminifera, which records a global ice volume and deep water temperature signal. To date, ?18O alignment has been performed by manual, qualitative comparison or by deterministic algorithms. Here we present a hidden Markov model (HMM) probabilistic algorithm to find 95% confidence bands for ?18O alignment. This model considers the probability of every possible alignment based on its fit to the ?18O data and transition probabilities for sedimentation rate changes obtained from radiocarbon-based estimates for 37 cores. Uncertainty is assessed using a stochastic back trace recursion to sample alignments in exact proportion to their probability. We applied the algorithm to align 35 late Pleistocene records to a global benthic ?18O stack and found that the mean width of 95% confidence intervals varies between 3 and 23 kyr depending on the resolution and noisiness of the record's ?18O signal. Confidence bands within individual cores also vary greatly, ranging from ~0 to >40 kyr. These alignment uncertainty estimates will allow researchers to examine the robustness of their conclusions, including the statistical evaluation of lead-lag relationships between events observed in different cores.

Lin, Luan; Khider, Deborah; Lisiecki, Lorraine E.; Lawrence, Charles E.

2014-10-01

118

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

119

The Future of Offshore Wind Energy  

E-print Network

1 The Future of Offshore Wind Energy #12;2 #12;3 Offshore Wind Works · Offshore wind parks: 28 in 10 countries · Operational since 1991 · Current installed capacity: 1,250 MW · Offshore wind parks in the waters around Europe #12;4 US Offshore Wind Projects Proposed Atlantic Ocean Gulf of Mexico Cape Wind

Firestone, Jeremy

120

Electrokinetic improvement of offshore foundations  

NASA Astrophysics Data System (ADS)

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

Micic, Silvana

121

Quaternary stratigraphic usage in North America: A brief survey  

NASA Astrophysics Data System (ADS)

A survey of North American Quaternary workers shows that a majority of those polled believe the distinction between the geologic-climate stratigraphic term “Wisconsin Glaciation” and the chrono-stratigraphic term “Wisconsinan Stage” is important in North America. More than two-thirds of the respondents indicated that they favor use of local or regional geographic terms for the last glaciation outside of central and eastern North America. A majority also advocated informal use of local or regional names for subdivisional stratigraphic units. Almost three-fourths of the respondents suggested that the Pleistocene-Holocene boundary be placed at 10,000 14C yr B.P. Most feel that the pre-Wisconsin glacial stage terminology should be retained, but in a revised, well-dated stratigraphic system. *Present addresses: (Nelson) Engineering and Research Center, U.S. Water and Power Resources Service, Denver Federal Center, Denver, Colorado 80225; (Locke) Department of Geology, Williams College, Williamstown, Massachusetts 01267

Nelson, Alan R.; Locke, William W., III

1981-03-01

122

Towards a stratigraphic record of dynamic topography  

NASA Astrophysics Data System (ADS)

The erosion of mountainous terrain and contemporaneous deposition of sediment within the adjacent basins modifies the applied load upon the surface of the Earth. A simple argument can then be made that an increase in rainfall would lead to increased erosion and deposition, and would therefore directly impact the dynamics and evolution of the linked mountain-basin system. Key to the exploration of this argument is an understanding of how efficient erosion is and the acceptable way to model long-term (> million years) Earth surface processes at relatively large spatial scales (100's of kilometres). Surface processes are complex and chaotic, and up-scaling from individual bed-load processes to the scale of a single river system has yet to be achieved. To overcome this we attempt to find the laws that describe sediment transport on a gross scale. We develop a general and simple length dependent diffusive sediment transport law to model both erosion and deposition that includes the concentrative effects of river systems. This allows us to collapse sediment transport onto a line and couple erosion and deposition with plate flexure. We use this model to interogate the impact of long-term (millions of years) change in rainfall and uplift rate on the stratigraphic archive of continental interior basins. Tilting of the interior of the North American continent due mantle flow, be it lithosphere instability or remnant subducting slabs, has been invoked to be the driver of change in rates and magnitude of river incision observed within the Great Plains. But, an increase in rainfall would also lead to an increase in river incision. Assuming that grains are deposited selectively by size we explore the signals recorded in the stratigraphic record by change in long-wavelength uplift and long-term rainfall. We find that under simple forcing conditions the modelled landscape is highly responsive to change in climate. Increase in rainfall causes incision of previously deposited materialand the pro-gradation of coarse grains down system. Increase in uplift within the catchment and subsidence within the basin, however, has a delayed effect as the landscape takes time to respond to the increase in slope. Furthermore, an increase in uplift causes pro-gradation of the depositional system, and subsequent incision if uplift rates reduce. The degree of incision is crucially dependent on the prescribed boundary condition at the depositional edge of the model domain. Fixed elevation increases the degree of incision, yet fixed slope reduces incision. The model predictions are supported by landscape development of the Rocky Mountain - Great Plains region from the late Miocene to Pleistocene, where: (1) incision was initiated in the Late Miocene due to tectonic tilting (without a significant change in grain-size); (2) deposition of a thick succession of conglomerate (coarser than underlying Miocene succession) ensued from ca. 3.5 to 2.6 Ma, associated with extreme sediment loads and a wetter mid-Pliocene climate; and (3) a period of incision from 2.6 Ma onwards that was climatically-driven, and coincides with the onset of Northern Hemisphere glaciation.

Armitage, J. J.; Duller, R. A.

2012-12-01

123

An integrated approach to offshore wind energy assessment: Great Lakes 3D Wind Experiment. Part I. Calibration and testing RJ Barthelmie1, SC Pryor1, CM Smith1, P Crippa1, H Wang1, R. Krishnamurthy2, R. Calhoun2, D Valyou3, P Marzocca3, D Matthiesen4, N.  

E-print Network

An integrated approach to offshore wind energy assessment: Great Lakes 3D Wind Experiment. Part I Government or any agency thereof." Introduction An experiment to test wind and turbulence measurement strategies was conducted at a northern Indiana wind farm in May 2012. The experimental design focused

Polly, David

124

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

125

Submarine fans in a sequence stratigraphic framework  

SciTech Connect

Submarine fans are fan- or cone-shaped turbiditic deposits formed in upper bathyal or deeper water depths. Within a sequence stratigraphic framework, these basin-floor turbidites can occur during lowstand-fan or lowstand-wedge systems tract time. During lowstand fan time, streams are rejuvenated and depocenters shift from the coastal plain to the upper slope, causing retrogradational slope failure and canyon formation. The sediment delivered here bypasses the canyon and continues down the slope as a succession of gravity flows and is deposited as fan-shaped turbiditic deposits at the base of the slope. Seismic and outcrop evidence suggest that these sand-prone deposits are abruptly introduced into the basin and are generally characterized by subtle external mounding and internal bidirectionally down lapping seismic reflections where seismically resolvable. Deep-water sediment deposited during this interval has no coeval shelf equivalent. During lowstand wedge time, streams cease down cutting and valleys which have been freshly incised begin to fill. Because coarse sediment will preferentially be deposited within these incised valleys, the sand-to-mud ratio delivered to the upper slope will be decreased and, consequently, there is an inherent difference between submarine fans deposited at this time and those deposited during lowstand fan time. Deposition during lowstand wedge time is characterized seismically by slope front fill or wedge-shaped geometries down lapping the earlier submarine fan (i.e., deposited during lowstand fan time). These shale-prone deposits are largely comprised of thinner-bedded turbidites as well as the occasional leveed channel.

Posamentier, H.W.; Erskine, R.D.; Mitchum, R.M.; Vail, P.R.

1987-05-01

126

Cost of Offshore Wind Energy Charlene Nalubega  

E-print Network

Cost of Offshore Wind Energy and Industrial Engineering The focus of my research is to estimate the cost of floating offshore wind turbines water as well as on land based wind farms. The specific offshore wind energy case under consideration

Mountziaris, T. J.

127

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

128

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

129

Mooring Line Modelling and Design Optimization of Floating Offshore Wind Turbines  

E-print Network

Mooring Line Modelling and Design Optimization of Floating Offshore Wind Turbines by Matthew Thomas Mooring Line Modelling and Design Optimization of Floating Offshore Wind Turbines by Matthew Thomas Jair tests performed on three floating turbine designs using test cases incorporating both steady

Victoria, University of

130

Stratigraphic controls on fluid and solute fluxes across the sediment-water interface of an estuary  

USGS Publications Warehouse

Shallow stratigraphic features, such as infilled paleovalleys, modify fresh groundwater discharge to coastal waters and fluxes of saltwater and nutrients across the sediment–water interface. We quantify the spatial distribution of shallow surface water–groundwater exchange and nitrogen fluxes near a paleovalley in Indian River Bay, Delaware, using a hand resistivity probe, conventional seepage meters, and pore-water samples. In the interfluve (region outside the paleovalley) most nitrate-rich fresh groundwater discharges rapidly near the coast with little mixing of saline pore water, and nitrogen transport is largely conservative. In the peat-filled paleovalley, fresh groundwater discharge is negligible, and saltwater exchange is deep (?1 m). Long pore-water residence times and abundant sulfate and organic matter promote sulfate reduction and ammonium production in shallow sediment. Reducing, iron-rich fresh groundwater beneath paleovalley peat discharges diffusely around paleovalley margins offshore. In this zone of diffuse fresh groundwater discharge, saltwater exchange and dispersion are enhanced, ammonium is produced in shallow sediments, and fluxes of ammonium to surface water are large. By modifying patterns of groundwater discharge and the nature of saltwater exchange in shallow sediments, paleovalleys and other stratigraphic features influence the geochemistry of discharging groundwater. Redox reactions near the sediment–water interface affect rates and patterns of geochemical fluxes to coastal surface waters. For example, at this site, more than 99% of the groundwater-borne nitrate flux to the Delaware Inland Bays occurs within the interfluve portion of the coastline, and more than 50% of the ammonium flux occurs at the paleovalley margin.

Sawyer, Audrey H.; Lazareva, Olesya; Kroeger, Kevin D.; Crespo, Kyle; Chan, Clara S.; Stieglitz, Thomas; Michael, Holly A.

2014-01-01

131

Pioneering offshore excellence  

SciTech Connect

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

Kent, R.P.; Grattan, L.

1996-11-01

132

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

133

Houlsby, G. T., Kelly, R. B., Huxtable, J. & Byrne, B. W. (2005). Geotechnique 55, No. 4, 287296 Field trials of suction caissons in clay for offshore wind turbine  

E-print Network

­296 287 Field trials of suction caissons in clay for offshore wind turbine foundations G. T. HOULSBY*, R at the Bothkennar test site is described. The tests are relevant to the design of foundations for offshore wind quant a` la conception des fondations des turbines a` vent. INTRODUCTION The offshore wind energy

Byrne, Byron

134

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

135

Stratigraphic framework and distribution of lignite on Crowleys Ridge, Arkansas  

USGS Publications Warehouse

The purpose of this report is to establish a stratigraphic framework of lignite beds and associated strata of Crowleys Ridge, Arkansas. Drill hole data provided by the Arkansas Geological Commission is used in the synthesis and interpretation. Areas containing lignite of potential resource value are also delineated. To illustrate the regional stratigraphic framework of Crowleys Ridge, a cross section was constructed from logs of selected oil and gas test wells, along or adjacent to the north-south trending ridge over a distance of about 115 miles. This section reveals that lignite-bearing Tertiary formations dip gently southward along the ridge. The Paleocene-Eocene Wilcox Group forms the bedrock in the northern part of the ridge and successively younger bedrock of the Eocene Claiborne and Jackson Groups is identified in the central and southern part of the ridge. Crowleys Ridge is mantled with alluvium and loess of Quaternary age, and sand and gravel beds of the Lafayette Formation of Pliocene (?) age that unconformably overlie the Paleocene and Eocene rocks. The thickness of lignite-bearing sedimentary deposits ranges from 830 feet in the north to 2,480 feet in the south. The Wilcox, Claiborne, and Jackson Groups of Paleocene and Eocene age are believed to be fluvial-deltaic in origin. The detailed vertical and horizontal stratigraphic characteristics and distribution of lignite beds in the sediments were determined by constructing seven cross sections from lithologic and geophysical logs of the lignite investigations on Crowleys Ridge by the Arkansas Geological Commission and private companies. Correlation and interpretation of the lignite-bearing strata reveal ten lignite beds of resource potential. These lignite beds range from a few inches to 9.5 ft in thickness and are assigned to stratigraphic intervals that are designated as zone 1 through 7. Zone 1 is near the middle of the Wilcox Group and zone 7 is near the middle of the overlying Claiborne Group. Some of these lignite beds are correlated over distances as much as 30 miles. Other lignite beds thin to a few inches thick and disappear within short distances. Four areas are delineated on Crowleys Ridge that contain one or more lignite beds each 2.5 feet or more thick. Strippable lignite is limited to 300 feet in this area, therefore, all holes were drilled to 300 feet or less. Chemical analyses of eight lignite samples from Crowleys Ridge are on record with the U.S. Geological Survey's National Coal Resources Data System. Two of the samples are from the Wilcox Group, and six are from the Claiborne Group, but the lignite beds from which the samples were taken are unidentified. However, the analyses are believed to be representative of the lignite within the lignite-bearing sequence. The two Wilcox samples had moisture values of 36.3 and 40.1 percent; ash, 30.5 and 20.5 percent (U.S. Bureau of Mines); sulfur content, 0.3 and 1.0 percent; and Btu values, 3,910 and 4,590 on an as received basis. The six Claiborne samples had moisture values ranging from 34.7 to 43.7 percent; ash from 11.9-28.2 percent (USBM); sulfur content, 0.3-3 percent; and Btu values, 3,400 to 5,160. U.S. Geological Survey average ash content for the eight samples was 36.22 percent, and the major oxides are SiO2 (60.75 percent), Al2O3 (15.23 percent), CaO (6.96 percent), Fe2O3 (6.65 percent), and SO3 (5.64 percent). No anomalous values were recorded for the trace element content. Lignite is not currently mined on Crowleys Ridge. It has potential for use as a fuel for direct firing of boilers to generate electricity. It also has potential for gasification to produce pipeline gas, and for liquefaction to produce fuel oil. More drilling and analyses are needed to better define the quantity and quality of lignite beds within the four significant areas with resource potential and to determine the extent of lignite beds 2.5 ft or more thick that occur in several isolated areas.

Meissner, Charles R.

1983-01-01

136

Bahrain's offshore banking center  

SciTech Connect

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

Gerakis, A.S.; Roncesvalles, O.

1983-01-01

137

Mobile offshore drilling units for frontier areas  

SciTech Connect

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

Kelly, P.L.

1983-04-01

138

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

139

Methane Seeps along Offshore Virginia  

USGS Multimedia Gallery

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

140

Sequence-stratigraphic implications of glacial-eustatic Pennsylvanian cyclothems in North America  

SciTech Connect

Only glacial eustasy accounts for all characteristics of Pennsylvanian northern Midcontinent cyclothems that consist of transgressive limestone, offshore ( core') shale, regressive limestone, and variable nearshore to terrestrial shale. Because of the rapidity of glacial eustatic fluctuations of sea level relative to tectonic movements of the shelf or to sediment filling of the large accommodation space provided by sea-level highstand, sequence-stratigraphic concepts and terminology require modification for these cyclothems. It is mainly the condensed intervals of sediment-starved, phosphate- and conodont-rich core shales that represent true highstand deposits on the mid to lower shelf (which is all that is presently preserved). The basic cyclothem was modified in Texas and Illinois by detrital overwhelming of regressive limestone deposition from nearer sources, but similar widespread condensed intervals still represent most of highstand. Higher shelf deposits are preserved in the Appalachian basin where phosphate- glaucony- and conodont-rich Conemaugh marine limestones represent highstand deposits in shallower water. These are penetrated locally eastward by deltaic clastics, which also represent highstand as well as early regression. Later regression involved greater fluvial incision, local terrestrial deposition and widespread paleosol formation, which continued through lowstand and early transgression. Late transgression produced widespread coal swamps, migrating ahead of inundation as a result of rising water table and increasing source of rainfall.

Heckel, P.H. (Univ. of Iowa, Iowa City, IA (United States). Dept. of Geology)

1993-02-01

141

Simulation of Stratigraphic Architecture from Statistical and Geometrical Characterizations  

Microsoft Academic Search

Stratigraphic modeling based on physical and geologic principles has been improved by more sophisticated process models and increased computer power. However, such efforts may reach a limit in their predictive power because of the stochastic, multiscaled nature of the physical processes involved. Building on techniques from the geostatistical literature, a conditional simulation method, dubbed SimStrat, has been developed to improve

John A. Goff

2000-01-01

142

Stratigraphic and paleogeographical significance of Silurian acritarchs from Saudi Arabia  

Microsoft Academic Search

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

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

1995-01-01

143

Grossman and others APPENDIX I. COLLECTING LOCALITIES AND STRATIGRAPHIC  

E-print Network

route I-435, on south bank of Kansas River in northwestern Kansas City, Kansas. Section located on west I-435, on south bank of Kansas River in northwestern Kansas City, Kansas. Section located on westGrossman and others APPENDIX I. COLLECTING LOCALITIES AND STRATIGRAPHIC HORIZONS IN KANSAS AND NEW

Grossman, Ethan L.

144

GENETAB: a basic program for editing stratigraphic range charts  

NASA Astrophysics Data System (ADS)

The program GENETAB draws stratigraphic range charts from information in any type of geologic database. It provides output on a standard microcomputer printer. The version described in this paper permits the use of data from Mesozoic strata, and draws cooccurrence intervals of both precise and imprecise ranges. The program is written in BASIC, and accepts input from dBase files.

Vrielynck, B.; Granlund, A.

145

New Approaches to field-based analysis of stratigraphic sections  

NSDL National Science Digital Library

The project involves measurement of stratigraphic sections in the field and completion of a report that summarizes the nature of the section and a variety of interpretations. It includes data collection, separate interpretations of depositional processes and paleoenvironments, use of cut slabs and thin sections, and the use of mock expert "consulting" sessions with groups of students.

Paul Myrow

146

Hybrid offshore structure  

SciTech Connect

An articulated offshore structure is described for use in a body of water, the structure comprising: a substantially rigid lower section, the lower section extending upwardly from the bottom of the body of water to a pivot point located intermediate the bottom and the surface of the body of water; a compliant upper section extending upwardly from the pivot point to a position at or above the surface of the body of water; pivot means located proximate pivot point, the pivot means interposed between and connected to the lower section and upper section and adapted to permit the upper section to pivot laterally relative to the lower section; torsion means connected to the upper section and the lower section, the torsion means adapted to transmit torsional loads from the upper section to the lower section; the pivot means being positioned above the bottom of the body of water a distance of between about 10 percent and about 50 percent of the total depth of the body of water so as to substantially minimize the weight of the structure while maintaining the flexural vibration period of the structure at or below a preselected maximum flexural vibration period.

Finn, L.D.; Maus, L.D.

1986-09-09

147

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

148

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

1996-12-31

149

Stratigraphic characterization of the Anthropocene: a progress report  

NASA Astrophysics Data System (ADS)

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

Zalasiewicz, Jan

2014-05-01

150

High-alloy materials for offshore applications  

SciTech Connect

High-alloy materials possessing good corrosion resistance in hot, sour brines are being seriously considered for offshore applications. These alloys are available in a wide range of strength levels which can be attained by the methods of cold working or precipitation hardening. Results of testing INCONEL alloys 625 and 718 and INCOLOY alloys 825 and 925 for resistance to general corrosion, hydrogen embrittlement, and stress-corrosion cracking (SCC) are presented. This paper also contrasts the range of mechanical properties available in precipitation-hardened materials with properties of cold-worked alloys.

Lemke, T.F.; Harris, J.A.

1983-05-01

151

Offshore Wind Energy Market Overview (Presentation)  

SciTech Connect

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

Baring-Gould, I.

2013-07-01

152

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

153

Coupled dynamic analysis of floating offshore wind farms  

E-print Network

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

Shim, Sangyun

2009-05-15

154

Offshore Aquaculture in the United States  

E-print Network

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

155

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

E-print Network

Offshore Coastal Wind Speed Gradients: issues for the design and development of large offshore@globalnet.co.uk · WEB SITE: www.multi-science.co.uk #12;Offshore Coastal Wind Speed Gradients: issues for the design-situ and remote sensing data from offshore wind farms in Denmark, are used to examine both horizontal and vertical

Pryor, Sara C.

156

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

157

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

SciTech Connect

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

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

1996-09-01

158

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

159

Evolution of deep-water stratigraphic architecture, Magallanes Basin, Chile  

Microsoft Academic Search

The ˜4000 m thick and ?20 Myr deep-water sedimentary fill of the Upper Cretaceous Magallanes Basin was deposited in three major phases, each with contrasting stratigraphic architecture: (1) the oldest deep-water formation (Punta Barrosa Formation) comprises tabular to slightly lenticular packages of interbedded sandy turbidites, slurry-flow deposits, and siltstone that are interpreted to record lobe deposition in an unconfined to weakly ponded

Brian W. Romans; Andrea Fildani; Stephen M. Hubbard; Jacob A. Covault; Julie C. Fosdick; Stephan A. Graham

2011-01-01

160

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

161

CHRONOS's Paleontological-Stratigraphic Interval Construction and Analysis Tool (PSICAT)  

NASA Astrophysics Data System (ADS)

The Paleontological-Stratigraphic Interval Construction and Analysis Tool (PSICAT) is a Java-based graphical editing tool for creating and viewing stratigraphic column diagrams from drill cores and outcrops. It is customized to the task of working with stratigraphic columns and captures data digitally as you draw and edit the diagram. The data and diagrams are captured in open formats, and integration with the CHRONOS system (www.chronos.org) will allow the user to easily upload their data and diagrams into CHRONOS. Because the data and diagrams are stored in CHRONOS, they will be accessible to anyone, anywhere, at any time. PSICAT is designed with a modular, plug-in-based architecture that will allow it to support a wide variety of functionality, tasks, and geoscientific communities. PSICAT is currently being developed for use by the ANDRILL project (http://www.andrill.org) on their upcoming drilling expeditions in Antarctica, but a general community version will be also available. PSICAT will allow unprecedented communication between Antarctica-based scientists and shore-based scientists, potentially allowing shore-based scientists to interact in almost real time with on-ice operations and data collection.

Reed, J. A.; Cervato, C.; Fielding, C. R.; Fils, D.

2005-12-01

162

Antarctic Drilling Recovers Stratigraphic Records From the Continental Margin  

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

163

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

SciTech Connect

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

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

1996-01-01

164

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

SciTech Connect

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

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

1996-12-31

165

Offshore wind resource assessment through satellite images  

E-print Network

1 Slide no. 4 Offshore wind resource assessment through satellite images Charlotte Bay Hasager images for offshore wind ressource assessment in lieu of in-situ mast observations #12;4 Slide no Hasager, Dellwik, Nielsen and Furevik, 2004, Validation of ERS-2 SAR offshore wind-speed maps in the North

166

OFFSHORE WIND FARMS Guidance note for Environmental  

E-print Network

OFFSHORE WIND FARMS Guidance note for Environmental Impact Assessment In respect of FEPA and CPA requirements Version 2 - June 2004 #12;Offshore Wind Farms: Guidance Note for Environmental Impact Assessment 2004 #12;Offshore Wind Farms: Guidance Note for Environmental Impact Assessment in Respect of FEPA

167

Offshore Wind Power Farm Environmental Impact Assessment  

E-print Network

Horns Rev Offshore Wind Power Farm Environmental Impact Assessment on Water Quality #12;Prepared with a planned 150 MW offshore wind farm at Horns Rev, an assessment was made of the effects the wind farm would for the preparation of EIA studies for offshore wind farms." Horns Rev is situated off Blåvands Huk, which is Denmark

168

Multi-scale alluvial fan heterogeneity modeled with transition probability geostatistics in a sequence stratigraphic framework  

NASA Astrophysics Data System (ADS)

The complexity of alluvial fan depositional systems makes detailed characterization of their heterogeneity difficult, yet such detailed characterizations are commonly needed for construction of reliable groundwater models. The transition probability geostatistical approach provides a means to quantify the distribution of hydrofacies in the subsurface. However, a key assumption used in this and other geostatistical approaches is that of stationarity. Stratigraphic character often varies within a deposit, making this assumption tenuous. Sequence stratigraphic concepts help us overcome this problem by dividing the strata into units that have similar properties, called sequences, based on recognition of unconformities and timelines within the sedimentary record. By using transition probability geostatistics in a sequence stratigraphic framework, realizations of the alluvial fan facies distributions are produced that account for multi-scale heterogeneity represented by spatially variable hydrofacies within sequences, laterally extensive aquitard units at sequence boundaries, and spatial variability attributes that are unique to each sequence. Incorporation of conceptual geologic information into the Markov chain model of transition probability also allows development of improved coregionalization models in the typically undersampled, lateral directions. The Kings River Alluvial Fan, located southeast of Fresno, California, provides an excellent test case for the approach. Several sequences within the alluvial fan were produced by outwash from Pleistocene glaciations in the Sierra Nevada Mountains. Five sequences, separated by large-scale (>3 km laterally), mature, red paleosols, were recognized in the alluvial fan strata. Markov chain models were developed to characterize the intermediate-scale (0.3-1.5 km laterally) distribution of hydrofacies in each individual sequence and to characterize the spatial distribution of paleosols. Separate conditional simulation of each sequence provides realizations of hydrofacies distributions. Combining these five sequence realizations into a single realization, then overprinting the paleosol distributions onto this realization, produced a geologically plausible image of the subsurface facies distribution that accounts for non-stationarity between stratigraphic units. Importantly, the resulting realization preserves the lateral continuity of the large-scale sequence boundary paleosols, which are potentially important confining beds within the fan deposits. Additionally, facies juxtaposition tendencies (e.g. upward fining tendencies of the fluvial deposits) and known directional anisotropy and dip of units within the fan are preserved in the realization. These physical attributes, accurately reproduced by the geostatistical method, are essential components of the overall hydrogeologic character of the alluvial fan.

Weissmann, G. S.; Fogg, G. E.

1999-12-01

169

P-wave velocity features of methane hydrate-bearing turbidity sediments sampled by a pressure core tool, from the first offshore production test site in the eastern Nankai Trough, Japan  

NASA Astrophysics Data System (ADS)

Turbidite sediments around the production test site at Daini-Atsumi knoll were deposited under channel and lobe environments of a submarine fan. Changes in physical properties of the sediments are likely caused by differences in the depositional environments. In addition, methane hydrate (MH) crystals growing among sediment grains alter the sediment's original physical properties. Thus, distinguishing between hydrate-bearing sediment and hydrate-free sediment based only on physical property changes measured during downhole logging can be difficult. To more precisely analyze sediment properties, core samples of MH-bearing sediments were taken at the first offshore MH production test site. Samples were collected using a wireline hybrid pressure coring system (Hybrid PCS), which retains downhole pressure, thereby preventing dissociation of MH in the sampled cores. Nondestructive, high-pressure analyses were conducted in both the 2012 summer drilling campaign and a 2013 winter laboratory study in Sapporo. To handle Hybrid PCS cores during the pressure coring campaign in the summer of 2012, a pressure core analysis and transfer system (PCATS) was installed on the research vessel Chikyu (Yamamoto et al., 2012). PCATS P-wave velocity measurements were made at in situ water pressure without causing any core destruction or MH dissociation. In January 2013, Georgia Tech (GT), USGS, AIST, and JOGMEC researchers used pressure core characterization tools (PCCTs) developed by GT to re-measure the P-wave velocity of the MH-bearing sediments at high pressure and low, non-freezing temperature. In the PCATS analysis, results showed a difference of more than 1,200 m/s in P-wave velocities between the MH-bearing sandy and muddy layers. This difference in P-wave velocities was confirmed by PCCTs measurements. P-wave velocities within the turbidite interval tend to decrease upward with the textural grading of the turbidite. Our result implies that MH concentration, which is related to the pore size of sediments, tends to be highest in coarser layers, enhancing the P-wave velocity change through the turbidite. Acknowledgement Authors would like to express thanks to Geotek for their assistance during the 2012 pressure core operation/analysis. This research is conducted as a part of MH21 research and the authors would like to express their sincere appreciation to MH21 and the Ministry of Economy, Trade and Industry for disclosure permission for this research.

Suzuki, K.; Santamarina, C. J.; Waite, W. F.; Winters, W. J.; Ito, T.; Nakatsuka, Y.; Konno, Y.; Yoneda, J.; Kida, M.; Jin, Y.; Egawa, K.; Fujii, T.; Nagao, J.

2013-12-01

170

Potential threats to offshore platforms  

Microsoft Academic Search

Increasingly spectacular acts of terrorism have led to growing concern that terrorists will move beyond the symbols of society and directly attack its technological and industrial vulnerabilities. Offshore platforms have been frequently mentioned among the potential targets terrorists might attack. This concern, however, has not resulted in extensive research like that devoted to possible threats to nuclear facilities, which have

1988-01-01

171

Offshore gas compression lags behind  

Microsoft Academic Search

Potentially vast oil and gas reserves exist in deeper water, discovered but inaccessible because present production technology has only reached the halfway point. Needs for gas compression offshore are similar to onshore: to compress natural casinghead (off separator) gas to transmission line pressures, to gas-lift wells incapable of flowing into limited flexibility gathering systems, and to compress for injection into

E. C. Jr

1969-01-01

172

Harmonic filtering for offshore industry  

Microsoft Academic Search

The application of a large number of Adjustable Speed Drives (ASDs) operating Electric Submersible Pumps (ESPs) on two separate offshore platforms, connected to a limited electrical power system on a tanker feeding power to the platforms via subsea power cables, presents technical problems involving high levels of harmonic distortions that experience shows can impact the overall system reliability. Here such

S. J. Merhej; W. H. Nichols

2009-01-01

173

Foundations for offshore wind turbines.  

PubMed

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

Byrne, B W; Houlsby, G T

2003-12-15

174

National Offshore Wind Energy Grid Interconnection Study  

SciTech Connect

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

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

2014-07-30

175

Offshore Renewable Energy R&D (Fact Sheet)  

SciTech Connect

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

Not Available

2011-10-01

176

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

177

Fossil preservation and the stratigraphic ranges of taxa  

NASA Technical Reports Server (NTRS)

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

Foote, M.; Raup, D. M.

1996-01-01

178

The 1911 Quadrant offshore Namibia; Exploration in a virgin basin  

SciTech Connect

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

Holtar, E.; Forsberg, A.

1995-08-01

179

Documenting volcano-tectonic episodes in Mars' stratigraphic record  

NASA Technical Reports Server (NTRS)

Global geologic maps of Mars at 1:15,000,000 scales were digitized to obtain accurate measurements of the areal extent of 90 geologic units. These data were used to determine the resurfacing history of Mars by volcanic, eolian, fluvial, periglacial, and impact processes. This work is presently being extended to focus on the extent, magnitude, and duration of volcanism and tectonism (mainly faulting) throughout each of the three time-stratigraphic systems. This work involves detailed mapping to assess volcano-tectonic episodes in terms of their occurrence in eight epochs that represent subdivisions of Martian periods.

Scott, David H.; Tanaka, Kenneth L.

1987-01-01

180

Offshore petroleum security: Analysis of offshore security threats, target attractiveness, and the international legal framework for the protection and security of offshore petroleum installations.  

E-print Network

??The offshore petroleum industry is of critical importance to the global economy. Offshore petroleum installations are considered elements of critical national infrastructure in many nation-States… (more)

Kashubsky, Mikhail

2011-01-01

181

Fatigue handbook: Offshore steel structures  

SciTech Connect

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

Almarnaess, A.

1985-01-01

182

Pipelaying in artic offshore waters  

SciTech Connect

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

Langner, C. G.

1985-11-19

183

Stratigraphic assessment of the Arcelia Teloloapan area, southern Mexico: implications for southern Mexico's post-Neocomian tectonic evolution  

NASA Astrophysics Data System (ADS)

Stratigraphic assessment of the "Tierra Caliente Metamorphic Complex" (TCMC) between Arcelia and Teloloapan in southern Mexico, based on photo interpretation of Landsat Thematic Mapper images and field mapping at the 1:100,000 scale, tests different tectonic evolution scenarios that bear directly on the evolution of the southern North American plate margin. The regional geology, emphasizing the stratigraphy of a portion of the TCMC within the area between Arcelia and Teloloapan is presented. Stratigraphic relationships with units in adjacent areas are also described. The base of the stratigraphic section is a chlorite grade metamorphic sequence that includes the Taxco Schist, the Roca Verde Taxco Viejo Formation, and the Almoloya Phyllite Formation. These metamorphic units, as thick as 2.7 km, are covered disconformably by a sedimentary sequence, 2.9 km thick, composed of the Cretaceous marine Pochote, Morelos, and Mexcala Formations, as well as undifferentiated Tertiary continental red beds and volcanic rocks. The geology may be explained as the evolution of Mesozoic volcanic and sedimentary environments developed upon attenuated continental crust. Our results do not support accretion of the Guerrero terrane during Laramide (Late Cretaceous-Paleogene) time.

Cabral-Cano, E.; Lang, H. R.; Harrison, C. G. A.

2000-10-01

184

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

185

Stratigraphic mapping of hydrated phases in Western Ius Chasma, Mars  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

186

1991 worldwide offshore contractors and equipment directory  

SciTech Connect

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

Not Available

1991-01-01

187

Infauna Monitoring Horns Rev Offshore Wind Farm  

E-print Network

#12;Infauna Monitoring Horns Rev Offshore Wind Farm Annual Status Report 2004 Published: 21 April-2004................................................. 48 Wind farm area (Turbine), Reference area (Ref

188

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

189

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

E-print Network

exploration, drilling and related maintenance tasks. Hercules Offshore operates in key oil producing sitesAbout Hercules Offshore Headquartered in Houston, Texas, Hercules Offshore serves the oil and gas industry with the largest fleet of mobile drilling platforms in the U.S. Gulf of Mexico, and the fourth

Fisher, Kathleen

190

Venusian extended ejecta deposits as time-stratigraphic markers  

NASA Technical Reports Server (NTRS)

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

Izenberg, Noam R.

1992-01-01

191

Accommodation and supply—a dual control on stratigraphic sequences  

NASA Astrophysics Data System (ADS)

It is widely accepted that both eustatic and tectonically controlled regional changes of sea level have contributed to the record of stratigraphic sequences. I suggest that environmental change be added as a third, autonomous control. Sedimentologic principles clearly indicate that sequences and their systems tracts are controlled by the interplay of two rates —the rate of change in accommodation (space available for sedimentation) and the rate of sediment supply. Sea level has direct control on accommodation, but its influence on sediment supply is remote and easily overshadowed by environmental factors. For instance, the record of the most recent sea-level rise is a transgressive systems tract where supply is low; it is a prograding highstand systems tract in deltas where the supply is high. Examples of sequence boundaries generated by changes in sediment supply include tectonically driven shifts in sediment input into basins, changes in ocean currents, pulsating supply from failure of submarine slopes and drowning of carbonate platforms by environmental stress. Furthermore, the stratigraphic sequences in fluviatile continental basins are physically removed from sea-level induced changes in accommodation and must have formed by changes in the rate and pattern of supply. Subaerial exposure of marine sediments at the sequence boundary is a most important criterion for recognizing sea level cycles as opposed to supply cycles. Other criteria include downstepping of shelf breaks and characteristic patterns in the spacing of time lines within sequences. Some third-order cycles (ca. 0.5-3 Ma duration) meet these criteria, others do not. Cycle-stacking patterns and the shifting facies belts on cratons indicate that many second- and third-order cycles lack pronounced exposure unconformities and represent gradual changes superimposed on more rapid, shorter oscillations. Seismic data yield poor images of these gradational changes because they lack resolution. Seismic models of outcrops show that near the limits of resolution, the seismic tool tends to portray rapid changes in facies and bed thickness, i.e. lateral variations in supply, as unconformities. Seismic unconformities do not necessarily correspond to unconformities in outcrop. The succession of stratigraphic sequences is best considered a composite record of sea-level and environmental change. Separating the various controls requires carefully planned experiments. Work on the oxygen-isotope curve—another proxy for sea level—has set an example in this respect.

Schlager, Wolfgang

1993-07-01

192

OWL representation of the geologic timescale implementing stratigraphic best practice  

NASA Astrophysics Data System (ADS)

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

Cox, S. J.

2011-12-01

193

76 FR 11503 - National Offshore Safety Advisory Committee; Vacancies  

Federal Register 2010, 2011, 2012, 2013, 2014

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

2011-03-02

194

78 FR 18618 - National Offshore Safety Advisory Committee; Vacancies  

Federal Register 2010, 2011, 2012, 2013, 2014

...in support of the exploration of offshore mineral and energy resources insofar...or similar entities engaged in offshore drilling; (c) One member representing...entities engaged in the support, by offshore supply vessels or other...

2013-03-27

195

76 FR 62817 - National Offshore Safety Advisory Committee  

Federal Register 2010, 2011, 2012, 2013, 2014

...support of the exploration of offshore mineral and energy resources...operate large OSVs. (6) Offshore Operators Committee (OOC...Team for DEEPWATER HORIZON drilling rig explosion and sinking...connection with the development of offshore renewable energy on the...

2011-10-11

196

78 FR 63233 - National Offshore Safety Advisory Committee; Meeting  

Federal Register 2010, 2011, 2012, 2013, 2014

...Foreign Flag Mobile Offshore Drilling Units. (4) Safety...Foreign Flag Mobile Offshore Drilling Units (MODUs...International Association of Drilling Contractors discussion...International and National offshore oil exploration...

2013-10-23

197

46 CFR 15.520 - Mobile offshore drilling units.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Mobile offshore drilling units. 15.520 Section...Vessels § 15.520 Mobile offshore drilling units. (a) The requirements in this section for mobile offshore drilling units (MODUs)...

2011-10-01

198

46 CFR 15.520 - Mobile offshore drilling units.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Mobile offshore drilling units. 15.520 Section...Vessels § 15.520 Mobile offshore drilling units. (a) The requirements in this section for mobile offshore drilling units (MODUs)...

2013-10-01

199

77 FR 26562 - Mobile Offshore Drilling Unit Dynamic Positioning Guidance  

Federal Register 2010, 2011, 2012, 2013, 2014

...USCG-2011-1106] Mobile Offshore Drilling Unit Dynamic Positioning Guidance...emergency procedures on a Mobile Offshore Drilling Unit. We received comments...particularly true for Mobile Offshore Drilling Units (MODUs), where a...

2012-05-04

200

46 CFR 15.520 - Mobile offshore drilling units.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Mobile offshore drilling units. 15.520 Section...Vessels § 15.520 Mobile offshore drilling units. (a) The requirements in this section for mobile offshore drilling units (MODUs)...

2010-10-01

201

78 FR 18614 - National Offshore Safety Advisory Committee  

Federal Register 2010, 2011, 2012, 2013, 2014

...in support of the exploration of offshore mineral and energy resources insofar...Hazardous Areas on Foreign Flag Mobile Offshore Drilling Units (MODUs); (c) Safety...Register notices that affect the offshore industry; (4) USCG Outer...

2013-03-27

202

76 FR 39410 - National Offshore Safety Advisory Committee; Vacancies  

Federal Register 2010, 2011, 2012, 2013, 2014

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

2011-07-06

203

46 CFR 15.520 - Mobile offshore drilling units.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Mobile offshore drilling units. 15.520 Section...Vessels § 15.520 Mobile offshore drilling units. (a) The requirements in this section for mobile offshore drilling units (MODUs)...

2012-10-01

204

77 FR 17491 - National Offshore Safety Advisory Committee  

Federal Register 2010, 2011, 2012, 2013, 2014

...and Federal Register notices that affect the offshore industry. (7) Offshore Operators Committee (OOC) update regarding...the industry comments received from the Mobile Offshore Drilling Unit Guidance Policy, Notice of...

2012-03-26

205

47 CFR 22.1007 - Channels for offshore radiotelephone systems.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Channels for offshore radiotelephone systems...Offshore Radiotelephone Service § 22.1007 Channels for offshore radiotelephone systems. The channels listed in this section are...

2013-10-01

206

47 CFR 22.1007 - Channels for offshore radiotelephone systems.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Channels for offshore radiotelephone systems...Offshore Radiotelephone Service § 22.1007 Channels for offshore radiotelephone systems. The channels listed in this section are...

2012-10-01

207

A contribution to regional stratigraphic correlations of the Afro-Brazilian depression - The Dom João Stage (Brotas Group and equivalent units - Late Jurassic) in Northeastern Brazilian sedimentary basins  

NASA Astrophysics Data System (ADS)

The Dom João Stage comprises an interval with variable thickness between 100 and 1200 m, composed of fluvial, eolian and lacustrine deposits of Late Jurassic age, based mainly on the lacustrine ostracod fauna (although the top deposits may extend into the Early Cretaceous). These deposits comprise the so-called Afro-Brazilian Depression, initially characterized as containing the Brotas Group of the Recôncavo Basin (which includes the Aliança and the Sergi Formations) and subsequently extended into the Tucano, Jatobá, Camamu, Almada, Sergipe, Alagoas and Araripe Basins in northeastern Brazil, encompassing the study area of this paper. The large occurrence area of the Dom João Stage gives rise to discussions about the depositional connectivity between the basins, and the real extension of sedimentation. In the first studies of this stratigraphic interval, the Dom João Stage was strictly associated with the rift phase, as an initial stage (decades of 1960-70), but subsequent analyses considered the Dom João as an intracratonic basin or pre-rift phase - without any relation to the active mechanics of a tectonic syn-rift phase (decades of 1980-2000). The present work developed an evolutionary stratigraphic and tectonic model, based on the characterization of depositional sequences, internal flooding surfaces, depositional systems arrangement and paleoflow directions. Several outcrops on the onshore basins were used to build composite sections of each basin, comprising facies, architectural elements, depositional systems, stratigraphic and lithostratigraphic frameworks, and paleocurrents. In addition to that, over a hundred onshore and offshore exploration wells were used (only 21 of which are showed) to map the depositional sequences and generate correlation sections. These show the characteristics and relations of the Dom João Stage in each studied basin, and they were also extended to the Gabon Basin. The results indicate that there were two main phases during the Dom João Stage, in which distinctive sedimentary environments were developed, reflecting depositional system arrangements, paleoflow directions were diverse, and continuous or compartmented basins were developed.

Kuchle, Juliano; Scherer, Claiton Marlon dos Santos; Born, Christian Correa; Alvarenga, Renata dos Santos; Adegas, Felipe

2011-04-01

208

Exploration for stratigraphic traps in a foreland basin using a sequence stratigraphic simulation: Examples from the Eocene\\/Oligocene of the Apure-Llanos basin, Venezuela  

Microsoft Academic Search

Foreland basin depositional sequences provide a sensitive record of the interaction between tectonism, eustatic sea level fluctuations, and sedimentation rates. Interplay between these controlling factors creates sedimentary geometries which are unique to this tectonic setting and form excellent stratigraphic hydrocarbon traps. Incised valley fill deposits, [open quote]forced regression[close quote] deposits, and combination structure-stratigraphic traps are the predominant reservoir types. In

J. Reistroffer; P. A. Levine; C. G. Kendall; A. Finno

1996-01-01

209

Drilling rate for the Cerro Prieto stratigraphic sequence  

SciTech Connect

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

Prian C, R.

1981-01-01

210

Stratigraphical distribution of the Ordovician conodont Erraticodon Dzik in Argentina  

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

211

Stratigraphic setting of transgressive barrier-island reservoirs with an example from the Triassic Halfway Formation, Wembley field, Alberta, Canada  

SciTech Connect

Established models for landward barrier-island migration focus primarily on the preservation pattern of transgressive facies in the shoreface which are typically thin and buried beneath finer grained marine lower shoreface-to-offshore sediments. In contrast, transgressive barrier-island sandstones in the Triassic Halfway Formation of Wembley field in Alberta are preserved interbedded with, and overlain by, backbarrier and nonmarine sediments. These transgressive barrier sandstones formed from coalescing washover fans during shoreface retreat and were subsequently [open quotes]abandoned[close quotes] as the shoreline stabilized and resumed progradation. The abandoned transgressive barrier sandstones were subsequently blanketed by backbarrier and nonmarine sediments as the coastline continued to prograde. Abandoned transgressive barrier island sandstones in the Halfway Formation are 2-6 m thick, up to 2 km wide, and form paleocoastline-parallel trends tens of kilometers in length. The trends define the paleolandward limit of transgressive events. The updip pinch-out of these sandstones in backbarrier mudstones forms a stratigraphic trap for hydrocarbons in Wembley field. Top seal is provided by nonmarine mudstones and evaporites which buried and abandoned transgressive barrier island. The sandstone has porosities and permeabilities averaging 11% and 63 md, respectively. By using well logs and cores to correlate individual parasequences in the Halfway Formation to their updip termination, it is possible to define the extent of associated marine flooding events and therefore identify hydrocarbon exploration targets for abandoned transgressive barrier-island sandstones. 58 refs., 13 figs., 2 tabs.

Willis, A.J.; Moslow, T.F. (Univ. of Alberta, Edmonton (Canada))

1994-05-01

212

Cenozoic stratigraphic evolution, North Sea and Labrador Sea  

SciTech Connect

The authors are studying Cenozoic correlation patterns, burial trends, and subsidence history of the Central North Sea, Labrador, and Orphan basins. The authors objectives are (1) to detail intraregional mid-high latitude biozonations using noise filtering and probabilistic zonation techniques; (2) to detail paleobathymetric trends from basin margins to centers; (3) to apply this knowledge to model basin evolution, in the perspective of the evolving North Atlantic Ocean; (4) to evaluate causes for the occurrence of major hiatuses and rapid changes of subsidence; and (5) to relate rapid changes in sedimentation in the last few millions of years to model observed undercompaction trends. Cenozoic microfossil assemblages in these basins are similar, related to similarities in sedimentary and paleoeceanographic conditions. In more basinal wells, flysch-type agglutinated foraminiferal assemblages occur, also known from Carpathians, Trinidad, and Moroccan foredeeps. Over 90% of agglutinated taxa are common between these basins, although local stratigraphic ranges vary sufficiently to rely on the concept of average ranges, rather than total ones for correlations. Cenozoic stratigraphic resolution in the North Sea and Labrador basins generally is in 3-5-Ma units. and paleobathymetric zonations define a minimum of five niches, from inner shelf to middle slope regimes. Significant hiatuses occurred in the late Eocene through the Miocene, particularly in northern Labrador and northern North Sea. Subsidence in the Labrador/Grand Banks passive margin half grabens was strongly influenced by Labrador Sea opening between anomalies 34 (Campanian) and 13 (early Oligocene), when subsidence exceeded sedimentation and bathyal conditions prevailed along the margin. Thermally induced subsidence in the central North Sea grabens was considerable in the late Paleocene, when the Norwegian Sea started to open.

Gradstein, F.M.; Grant, A.C.; Mudford, B.S. (Bedford Institute of Oceanography, Dartmouth, Nova Scotia (Canada)); Berggren, W.A. (Woods Hole Oceanographic Institute, MA (USA)); Kaminski, M.A. (Dalhousie Univ., Halifax, Nova Scotia (Canada)); D'Lorio, M.A. (Canada Centre for Remote Sensing, Nepean, Ontario (Canada)); Cloetingh, S. (Free Univ., Amsterdam (Netherlands)); Griffiths, C.M. (Univ. of Trondheim (Norway))

1990-05-01

213

Forward stratigraphic modeling of the Permian of the Delaware Basin  

SciTech Connect

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 distribution of reservoir and seal relationships. The approximately 30 m.y. interval modeled is composed of 2 km of platform strata and 3 km of basinal strata divided into 8 composite sequences (average 3 m.y. duration) and 45 high-frequency sequences (400 ky m.y. duration). A 130 km dip section through the basin margin Guadalupe/Deleware Mountain outcrop is inversely modeled to derive local tectonic subsidence and a sea level curve for the Permian. In this process, the highest and lowest shoreline positions of each sequence are interpreted based on facies description which are assumed to approximate the highest and lowest relative sea level. A eustatic sea level curve is calculated by restoring these shoreline positions and removing local tectonic subsidence using a polynomial fit to the derived relative sea level curve. The quantitatively constrained curve for the Permian contains 2nd, 3rd, and 4th order 180m. This quantitatively constrained accommodation history (calculated eustatic curve and subsidence history) are input into the PHIL forward modeling program. Model variables of sediment supply are depositional system are adjusted to match known outcrop relations. The resulting model is potentially capable of predicting stratigraphy elsewhere in the basin using only subsidence history data from the inverse model.

Qiucheng, Ye; Kerans, C.; Bowman, S. (Univ. of Texas, Austin, TX (United States)) (and others)

1996-01-01

214

Forward stratigraphic modeling of the Permian of the Delaware Basin  

SciTech Connect

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 distribution of reservoir and seal relationships. The approximately 30 m.y. interval modeled is composed of 2 km of platform strata and 3 km of basinal strata divided into 8 composite sequences (average 3 m.y. duration) and 45 high-frequency sequences (400 ky m.y. duration). A 130 km dip section through the basin margin Guadalupe/Deleware Mountain outcrop is inversely modeled to derive local tectonic subsidence and a sea level curve for the Permian. In this process, the highest and lowest shoreline positions of each sequence are interpreted based on facies description which are assumed to approximate the highest and lowest relative sea level. A eustatic sea level curve is calculated by restoring these shoreline positions and removing local tectonic subsidence using a polynomial fit to the derived relative sea level curve. The quantitatively constrained curve for the Permian contains 2nd, 3rd, and 4th order 180m. This quantitatively constrained accommodation history (calculated eustatic curve and subsidence history) are input into the PHIL forward modeling program. Model variables of sediment supply are depositional system are adjusted to match known outcrop relations. The resulting model is potentially capable of predicting stratigraphy elsewhere in the basin using only subsidence history data from the inverse model.

Qiucheng, Ye; Kerans, C.; Bowman, S. [Univ. of Texas, Austin, TX (United States)] [and others

1996-12-31

215

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

216

Integrated stratigraphic studies of Paleocenelowermost Eocene sequences, New Jersey Coastal Plain: Evidence  

E-print Network

Integrated stratigraphic studies of Paleocene­lowermost Eocene sequences, New Jersey Coastal Plain. New Jersey Paleocene sequence boundaries correlate with those in other regions and with d18 O. Wright (2010), Integrated stratigraphic studies of Paleocene­lowermost Eocene sequences, New Jersey

217

Sequence-stratigraphic and mass-balance analysis of experimental stratigraphy  

NSDL National Science Digital Library

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

Liz Hajek

218

44 MArch 2006 Can offshore aquaculture  

E-print Network

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

Miami, University of

219

Powering the World: Offshore Oil & Gas Production  

E-print Network

Powering the World: Offshore Oil & Gas Production Macondo post-blowout operations Tad Patzek;Talk Outline. . . Fuels that run the U.S. and world Drilling and fracturing primer Complexity and risks, not resources or energy potentially available Offshore fields will be producing an increasing portion of global

Patzek, Tadeusz W.

220

CONMOW: Condition Monitoring for Offshore Wind Farms  

E-print Network

1 CONMOW: Condition Monitoring for Offshore Wind Farms Edwin Wiggelinkhuizen, Theo Verbruggen, Henk in practice the European project CONMOW (Condition Monitoring for Offshore Wind Farms) was started in November 2002. A small wind farm of five turbines has been instrumented with several condition monitoring

221

Corrosion control survey methods for offshore pipelines  

Microsoft Academic Search

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

C. P. Weldon; D. Kroon

1992-01-01

222

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

223

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

224

Influence of water and sediment supply on the stratigraphic record of alluvial fans and deltas: Process controls on stratigraphic completeness  

NASA Astrophysics Data System (ADS)

contains the most complete record of information necessary to quantitatively reconstruct paleolandscape dynamics, but this record contains significant gaps over a range of time and space scales. These gaps result from stasis on geomorphic surfaces and erosional events that remove previously deposited sediment. Building on earlier statistical studies, we examine stratigraphic completeness in three laboratory experiments where the topography of aggrading deltas was monitored at high temporal and spatial scales. The three experiments cover unique combinations in the absolute magnitudes of sediment and water discharge in addition to generation of accommodation space through base-level rise. This analysis centers on three time scales: (1) the time at which a record is discretized (t), (2) the time necessary to build a deposit with mean thickness equivalent to the maximum roughness on a surface (Tc), and (3) the time necessary for channelized flow to migrate over all locations in a basin (Tch). These time scales incorporate information pertaining to the time-variant topography of actively changing surfaces, kinematics by which the surfaces are changing, and net deposition rate. We find that stratigraphic completeness increases as a function of t/Tc but decreases as a function of Tc/Tch over the parameter space covered in the experiments. Our results suggest that environmental signals disconnected from a sediment routing system are best preserved in systems with low Tc values. Nondimensionalizing t by Tc, however, shows that preservation of information characterizing system morphodynamics is best preserved in stratigraphy constructed by systems with low water to sediment flux ratios.

Straub, Kyle M.; Esposito, Christopher R.

2013-06-01

225

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

226

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

227

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

228

ACCEPTED MANUSCRIPT Depositional model and stratigraphic architecture of rift climax Gilbert-type fan deltas (Gulf of  

E-print Network

ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT Depositional model and stratigraphic architecture of rift). Abstract Facies, depositional model and stratigraphic architecture of Pleistocene giant Gilbert-type fan to the Middle Group of the Corinth Rift infill and their stratigraphic development was strongly influenced

Paris-Sud XI, Université de

229

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

NASA Astrophysics Data System (ADS)

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

Kreidler, Tai Deckner

1997-12-01

230

Image processing in offshore engineering  

SciTech Connect

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

Rodriguez, M.V.R.; A. Oliveira, M. de; Almeida, M.E.T. de; Lorenzoni, C. [Petrobras-DEPRO, Rio de Janeiro (Brazil); Ferrante, A.J. [ISC Italia, Milano (Italy)

1995-12-31

231

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

232

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

233

Riser and wellhead monitoring for improved offshore drilling operations  

E-print Network

Riser and wellhead monitoring for improved offshore drilling operations Gullik A. Jensen, Ph ­ Offshore drilling with riser ­ On the riser and the riser joints ­ On damage and consequences · Operational · Two systems delivered. #12;Offshore drilling with riser ...a quick introduction #12;Offshore drilling

Nørvåg, Kjetil

234

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

E-print Network

OFFSHORE WIND FARM LAYOUT OPTIMIZATION (OWFLO) PROJECT: AN INTRODUCTION C. N. Elkinton* , J. F focused on land-based wind farms, rather than on offshore farms. The conventional method used to lay out that distinguish offshore wind farms from their onshore counterparts, the Offshore Wind Farm Layout Optimization

Massachusetts at Amherst, University of

235

Offshore Series Wind Turbine Variable Hub heights & rotor diameters  

E-print Network

3.6MW Offshore Series Wind Turbine GE Energy #12;Feature Variable Hub heights & rotor diameters-savings feature, considering the rigors of offshore power generation. The 3.6 MW offshore wind turbine also, for both on and offshore use. Special features include... As the world's first commercially available wind

Firestone, Jeremy

236

ORIGINAL PAPER Review of Methodologies for Offshore Wind Resource  

E-print Network

ORIGINAL PAPER Review of Methodologies for Offshore Wind Resource Assessment in European Seas A. M installation, operation and maintenance costs associated with offshore wind parks. Successful offshore wind. Keywords Wind energy Á Offshore Á Resources assessment Á European seas Á Wind mapping Á Wind climatology Á

Pryor, Sara C.

237

Quantifying the hurricane risk to offshore wind turbines  

E-print Network

Quantifying the hurricane risk to offshore wind turbines Stephen Rosea , Paulina Jaramilloa,1. Turbine tower buckling has been observed in typhoons, but no offshore wind turbines have yet been built be destroyed by hurricanes in an offshore wind farm. We apply this model to estimate the risk to offshore wind

Jaramillo, Paulina

238

Offshore drilling to increase in 1984  

SciTech Connect

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

Not Available

1984-05-01

239

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

240

Basal Murphy belt and Chilhowee Group -- Sequence stratigraphic comparison  

SciTech Connect

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

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

1994-03-01

241

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

242

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

243

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

244

Stratigraphic controls on seawater intrusion and implications for groundwater management, Dominguez Gap area of Los Angeles, California, USA  

USGS Publications Warehouse

Groundwater pumping has led to extensive water-level declines and seawater intrusion in coastal Los Angeles, California (USA). A SUTRA-based solute-transport model was developed to test the hydraulic implications of a sequence-stratigraphic model of the Dominguez Gap area and to assess the effects of water-management scenarios. The model is two-dimensional, vertical and follows an approximate flow line extending from the Pacific Ocean through the Dominguez Gap area. Results indicate that a newly identified fault system can provide a pathway for transport of seawater and that a stratigraphic boundary located between the Bent Spring and Upper Wilmington sequences may control the vertical movement of seawater. Three 50-year water-management scenarios were considered: (1) no change in water-management practices; (2) installation of a slurry wall; and (3) raising inland water levels to 7.6 m above sea level. Scenario 3 was the most effective by reversing seawater intrusion. The effects of an instantaneous 1-m sea-level rise were also tested using water-management scenarios 1 and 3. Results from two 100-year simulations indicate that a 1-m sea-level rise may accelerate seawater intrusion for scenario 1; however, scenario 3 remains effective for controlling seawater intrusion. ?? Springer-Verlag 2009.

Nishikawa, T.; Siade, A.J.; Reichard, E.G.; Ponti, D.J.; Canales, A.G.; Johnson, T.A.

2009-01-01

245

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

246

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

247

Visualization of vibration experienced in offshore platforms  

E-print Network

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

Patrikalakis, Alexander Marinos Charles

2010-01-01

248

Offshore oil in the Alaskan Arctic  

NASA Technical Reports Server (NTRS)

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

Weeks, W. F.; Weller, G.

1984-01-01

249

Future characteristics of Offshore Support Vessels  

E-print Network

The objective of this thesis is to examine trends in Offshore Support Vessel (OSV) design and determine the future characteristics of OSVs based on industry insight and supply chain models. Specifically, this thesis focuses ...

Rose, Robin Sebastian Koske

2011-01-01

250

Outsourcing, offshoring and the US office market  

E-print Network

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

Topolewski, Tanya M., 1969-

2004-01-01

251

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

252

Slow motion responses of compliant offshore structures  

E-print Network

SLOW MOTION RESPONSES OF COMPLIANT OFFSHORE STRUCTURES A Thesis by PEIMIN CAO Submitted to the Office of Gradnate Stndies of Texas AM'I University in partial fnliillment of the requirements for the degree of hiIASTER OF SCIENCE December... 1996 Major Subject: Ocean Engineering SLOW MOTION RESPONSES OF COMPLIANT OFFSHORE STRUCTURES A Thesis by PEIMIN CAO Submitted to Texas AEcM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved...

Cao, Peimin

2012-06-07

253

Neogene sequence stratigraphy, Nam Con Son Basin, offshore Vietnam  

SciTech Connect

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

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

1996-12-31

254

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

255

Stratigraphic analysis of Pennsylvania rocks using hierarchy of transgressive-regressive units  

NASA Astrophysics Data System (ADS)

Pennsylvanian stratigraphic sequences is described, interpreted, and correlated using a hierarchy of six scales of allocyclic, time-stratigraphic, transgressive-regressive units (abbreviated T-R units are inferred to be the net result of deposition during eustatic cycles of sea level change. The T-R units can be correlated across both marine and nonmarine facies in the Appalachian Basin. This permits differentiation of allocyclic T-R units from autocyclic T-R units or fluvial autocyclic units. The precise correlations also provide a time-stratigraphic framework for very accurate paleogeographic reconstructions. Paleogeographic maps were constructed for successive fifth-order marine events of the Glenshaw Formation (Upper Pennsylvanian) of the Northern Appalachian Basin. The hierarchal T-R unit approach is useful for understanding and predicting the location of marine units, claystones, various types of stratigraphic breaks, and economic mineral deposits.

Busch, R. M.

1984-06-01

256

Isometric Unfolding of Stratigraphic Grid Units for Accurate Property Populating: Mathematical Concepts  

E-print Network

Isometric Unfolding of Stratigraphic Grid Units for Accurate Property Populating: Mathematical original isometric unfolding process based on the minimization of the elastic tensor deformation in the unfolded volume for geostatistical computation. New aspects covered : We propose a new original isometric

Paris-Sud XI, Université de

257

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

E-print Network

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

González, Luis A.

258

Linking sedimentological, stratigraphic and diagenetic processes to understand unconventional reservoirs: the Upper Jurassic Vaca  

E-print Network

Linking sedimentological, stratigraphic and diagenetic processes to understand unconventional as to the scale of sedimentological variability within mudstone successions, and how related diagenetic alteration by Profs Taylor and Flint, to document the scale of sedimentological and diagenetic variability

Henderson, Gideon

259

A Proposed Time-Stratigraphic System for Protoplanet Vesta  

NASA Astrophysics Data System (ADS)

The Dawn Science Team completed a geologic mapping campaign during its nominal mission at Vesta, including production of a 1:500,000 global geologic map derived from High-Altitude Mapping Orbit (HAMO) images (70 m/pixel) [1] and 15 1:250,000 quadrangle maps derived from Low-Altitude Mapping Orbit (LAMO) images (20-25 m/pixel) [2]. In this abstract we propose a time-stratigraphic system and geologic time scale for the protoplanet Vesta, based on global geologic mapping and other analyses of NASA Dawn spacecraft data, supplemented with insights gained from laboratory studies of howardite-eucrite-diogenite (HED) meteorites and geophysical modeling. Our time-stratigraphic system for Vesta relates the geologic map (rock) units identified from geologic mapping to a series of time-rock units and corresponding time units that define a geologic time scale for Vesta. During the Dawn nominal mission it became clear that the south pole of Vesta hosts two large impact basins, the older Veneneia superposed by the younger Rheasilvia [3,4]. Two separate sets of large ridges and troughs were identified, one set encircling much of Vesta equatorial region (Divalia Fossae), and the other preserved in the heavily cratered northern terrain (Saturnalia Fossae). Structural analysis of these ridge-and-trough systems demonstrated that they are likely a tectonic response to the formation of the south polar basins: the Rheasilvia impact led to the formation of the Divalia Fossae, the Veneneia impact led to the Saturnalia Fossae [3,5]. Crater counts provide cratering model ages for the Rheasilvia impact of ~3.6 Ga and ~1 Ga, and ages for the Veneneia impact of ~3.8 Ga and >2.1 Ga using the lunar-derived and asteroid flux-derived chronologies, respectively. Despite the differences in absolute ages, it is clear that these two large impact events had global effects, and thus delineate the major periods of Vesta's geologic history. Zones of heavily cratered terrain (HCT: [6,7]) in the northern hemisphere adjacent to the Saturnalia Fossae Formation [1] likely are heavily modified portions of Vesta's ancient crust. The geologic units in and around the 68 x 58 km Marcia crater appear to delineate the most recent large impact event on Vesta. Crater counts of areas of the Marcia ejecta blanket give cratering model ages of ~120-150 Ma and ~220-390 Ma using the lunar-derived and asteroid flux-derived chronologies, respectively [6-8]. References: [1] Yingst, R.A., et al. (2014) PSS, in press. [2] Williams, D.A., et al. (2014a) Icarus, in review. [3] Jaumann, R. et al. (2012) Science 336, 687-690. [4] Schenk, P. et al. (2012) Science 336, 694-697. [5] Buczkowski, D.L. et al. (2013) GRL 39, L18205, doi:10.1029/2012GL052959. [6] Marchi, S. et al. (2012) Science 336, 690-694. [7] Schmedemann, N. et al. PSS (in revision). [8] Williams, D.A. et al. (2014b) Icarus, in revision.

Williams, David; Jaumann, Ralf; McSween, Harry; Raymond, Carol; Russell, Chris

2014-05-01

260

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

NASA Astrophysics Data System (ADS)

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

Alván, Aldo; von Eynatten, Hilmar

2014-10-01

261

Stratigraphic traps for petroleum in wind-laid rocks  

SciTech Connect

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

Fryberger, S.G.

1986-12-01

262

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

263

The Lanyard field, a structural-stratigraphic trap, Denver basin, Colorado  

Microsoft Academic Search

Cretaceous sandstones are oil and gas productive throughout a large area in Denver basin. The Lanyard field is a structural-stratigraphic trap which has produced in excess of 2,388,000 bbls of oil and 4.1 Bcf of gas from the D Sandstone. Productive sandstones are interpreted to be channel deposits on the basis of subsurface mapping and core examination. Seven Cretaceous stratigraphic

Sonnenberg

1982-01-01

264

Stratigraphic and structural controls on fluorspar mineralization in northern Valle Las Norias, Coahuila, Mexico  

E-print Network

STRATIGRAPHIC AND STRUCTURAL CONTROLS ON FLUORSPAR MINERALIZATION IN NORTHERN VALLE LAS NORIAS, COAHUILA, MEXICO A Thesis by ERIC JOHN RAPPORT Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1983 Major Subject: Geology STRATIGRAPHIC AND STRUCTURAL CONTROLS ON FLUORSPAR MINERALIZATION IN NORTHERN VALLE LAS NORIAS, COAHUILA, MEXICO A Thesis by ERIC JOHN RAPPORT Approved as to style and content by...

Rapport, Eric John

1983-01-01

265

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

266

Stratigraphic evidence for an early Holocene earthquake in Aceh, Indonesia  

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

267

Horns RevHorns Rev Offshore Wind FarmOffshore Wind Farm  

E-print Network

Horns RevHorns Rev Offshore Wind FarmOffshore Wind Farm #12;Prepared for: ELSAM A/S, Overgade 45......................................................................................................6-1 Annex 6.1. Wind Farm Area. Spring 2001.............................................................................6-1 Annex 6.2. Wind Farm Area. Autumn 2001

268

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

NASA Astrophysics Data System (ADS)

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

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

2004-05-01

269

Application of sequence and genetic stratigraphic concepts to Carboniferous coal-bearing strata: an example from the Black Warrior basin, USA  

NASA Astrophysics Data System (ADS)

Carboniferous strata provide an excellent example on which to test the application of genetic stratigraphic and sequence stratigraphic concepts. Both approaches are employed in the evaluation of the coal-bearing strata of the Black Warrior basin, south-eastern USA. Bounding hiatal surfaces have been recognized in the succession of rock that includes the Mary Lee coal zone. Within the framework of genetic stratigraphy, one genetic sequence has been identified comprised of offlap (progradational and aggradational facies) and onlap (aggradational and transgressive facies) components. Seven parasequence sets have been delimited according to the concepts of sequence stratigraphy. These have been ascribed to transgressive, highstand and shelf margin systems tracts. The identification of components of these contrasting frameworks provide the basis for evaluating other Carboniferous strata.

Gastaldo, Robert A.; Demko, Timothy M.; Liu, Yuejin

1993-07-01

270

Sanaga Sud field - Offshore Cameroon, west Africa  

SciTech Connect

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

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

1990-09-01

271

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

272

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

SciTech Connect

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

Not Available

1993-01-01

273

Structural and stratigraphic evolution of the Anza rift, Kenya  

NASA Astrophysics Data System (ADS)

The Anza rift is a large, multi-phase continental rift basin that links the Lamu embayment of southern Kenya with the South Sudan rifts. Extension and deposition of syn-rift sediments are known to have commenced by the Neocomian. Aptian-Albian strata have, thus far, not been encountered during limited drilling campaigns and, in at least one well, are replaced by a significant unconformity. Widespread rifting occurred during the Cenomanian to Maastrichtian, and continued into the Early Tertiary. Marine waters appear to have reached the central Anza rift in the Cenomanian, and a second marine incursion may have occurred during the Campanian. As no wells have yet reached basement in the basinal deeps, the possibility exists that the Anza rift may have initiated in the Late Jurassic, in conjunction with extension to the south in the Lamu embayment and to the north in the Blue Nile rift of Sudan. Structural and stratigraphic evolution in the Anza rift followed a pattern that has now been inferred in several rift settings. Early phases of extension were accommodated by moderately dipping faults that produced large stratal rotations. Sedimentary environments were dominantly fluvial, with associated small lakes and dune fields. Volcanic activity is documented for the early Neocomian, but its extent is unknown. This initial style of deformation and sedimentation may have continued through several of the earliest pulses of rifting. By the Late Cretaceous, a new system of steeply dipping faults was established, that produced a deep basin without significant rotation of strata in the north, and only minor rotation in the south. This basin geometry favored the establishment of large, deep lakes, which occasionally were connected to the sea. The older basins were partly cannibalized during the sedimentary in-filling of these successor basins. Early Senonian volcanism was encountered in one well, and reflection seismic evidence suggests that one or more thick, regionally extensive igneous sills were intruded, probably during the Early Tertiary. The change in rift style from early, strongly rotational, shallow basins to late, non-rotational, deep basins has been observed in the southern Gulf of Suez/northern Red Sea, the Southwestern Turkana/northern Kenyan rift, and at Anza. It therefore takes place in rifts in variable tectonic settings, with a wide range of volcanic activity and, presumably, with different driving mechanisms. The shift in deposition in each case is away from early rift-bounding faults toward the half-graben flexural margins, further in-board to the upper structural plate. This suggests at least some component of regional simple shear in the deformation history of the rifted lithosphere, either via broad shear zones or at discrete detachment surfaces.

Bosworth, William; Morley, Chris K.

1994-09-01

274

The Seabed Stability Zonation in Chinese Offshore  

NASA Astrophysics Data System (ADS)

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

Du, J.

2013-12-01

275

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

NASA Astrophysics Data System (ADS)

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

Pratt, Brian

2014-05-01

276

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

277

Offshore wind resource mapping using satellite observations  

NASA Astrophysics Data System (ADS)

Offshore wind mapping using satellite observations has been developed in the last decade. The archives of scatterometer and SAR images useful for ocean wind mapping contain data from around 8 to 15 years. For the statistical analysis it is important to include high numbers of observations. For scatterometer the wind resource analysis can be done based on around 6.500 individual readings, i.e. two observations daily since July 1999. Comparison results between meteorological observations at the Horns Rev offshore wind farm has been shown to compare well with QuikSCAT winds. Also SAR-based wind mapping has been compared to the same observations with good results. At present new analysis using more observations, available through the ESA EO Scandia-SAR project, show new maps of offshore winds in the North Sea and Baltic Sea. During year 2009 the first analysis for the new EU-Norsewind project (2008-2012) will be conducted. This project aims to map wind resource for a large offshore region in Northern Europe based on satellite, lidar and masts offshore.

Hasager, C. B.; Badger, M.

2009-04-01

278

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

SciTech Connect

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

Francois, D.K.

1994-12-31

279

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

SciTech Connect

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

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

2013-07-01

280

Solar power satellite offshore rectenna study  

NASA Technical Reports Server (NTRS)

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

1980-01-01

281

Investigation on installation of offshore wind turbines  

NASA Astrophysics Data System (ADS)

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

Wang, Wei; Bai, Yong

2010-06-01

282

Peculiarities of environmental genotoxicity in offshore zones of the Baltic and North Seas  

Microsoft Academic Search

Micronucleus test in different fish species has been considered a sensitive tool for the evaluation of genotoxic effects in coastal zones of the Baltic and North Seas. In the present study, micronuclei (MN) and other nuclear abnormalities in erythrocytes from peripheral blood and cephalic kidney were analyzed in flounder (Platichthys flesus) and cod (Gadus morhua) from 9 offshore locations in

Aleksandras Rybakovas; Thomas Lang

283

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

Code of Federal Regulations, 2014 CFR

... 2014-10-01 2014-10-01 false Mobile offshore drilling units (MODUs). 15.520 Section 15.520...Requirements; Inspected Vessels § 15.520 Mobile offshore drilling units (MODUs). (a) The requirements in...

2014-10-01

284

Hard Bottom Substrate Monitoring Horns Rev Offshore Wind Farm  

E-print Network

Hard Bottom Substrate Monitoring Horns Rev Offshore Wind Farm Annual Status Report 2003 #12;Hard Bottom Substrate Monitoring Horns Rev Offshore Wind Farm Annual Status Report 2003 Published: 14 May 2004

285

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

E-print Network

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

Ruzzante, Daniel E.

286

Plastic Limit Analysis of Offshore Foundation and Anchor  

E-print Network

This study presents the applications of plastic limit analysis to offshore foundations and anchors, including the drag embedment anchors (DEAs) for mobile offshore drilling units (MODU’s) and spudcan foundations for jack-up platforms. In deep waters...

Chi, Chao-Ming

2010-10-12

287

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

SciTech Connect

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

Not Available

2012-02-01

288

Exploration potential of offshore northern California basins  

SciTech Connect

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

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

1988-01-01

289

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

290

Marine gravity measurments offshore Sumatra  

NASA Astrophysics Data System (ADS)

Gravimetric measurements were carried out offshore Sumatra and Western Java by BGR during several expeditions with R.V. SONNE in 2005/2006 (cruises SO-186 and SO-189) and 1998/1999 (cruises SO-137 and SO-138). Gravity data were collected along profiles with a total length of nearly 33000 kilometers covering the area between Aceh in the north and the Sunda Strait in the south. The oceanic crust is characterized by slightly positive free-air gravity anomalies resulting from the influence of the subduction bulge due to the downgoing lithosphere. Additionally, there are N-S striking gravity anomalies on the oceanic crust, which can be correlated with a series of transform faults. Landward, an about 50 km wide negative anomaly runs from NW to SE, whereby the gravity values increase from about -160 mGal to about -40 mGal. They reflect the Sunda trench with water depths of 6500 m off the Sunda Strait decreasing to 4000 m off Aceh. This suggests that the thickness of the trench fill with sediments increases considerably from South to North. Landward, the gravity anomalies increase and reach a zone of relative maxima from +60 to +160 mGal in the outer arc high. This zone is about 120 km wide, whereby the outer arc high is less pronounced in the South than in the North. North of 2°N the outer arc high moves very close to the trench, reaching its maximum values already in the slope area. This indicates the recent accretion of large volumes of sediments. Further to the NE an elongated negative anomaly follows with values even lower than the minima associated with the trench. It corresponds to forearc basins filled with light sediments of up to 7 km thickness. Around the equator no basin has been developed. The EW striking gravity high in this area shows an obvious geographical correlation between with high free-air gravity associated with the Investigator Fracture Zone on the oceanic plate to the South. A causal link between the two seems likely. Subduction of the fracture zone is a possible cause for both the change in strike of the trench and forearc north of Nias. This would imply an eastward bend of the N-S trending ridge during the subduction process. Isostatic residual anomalies were calculated and a 3D density model of the subduction zone off Sumatra was developed, using BGR multi-channel seismic and refraction seismic as constraints.

Heyde, I.; Franke, D.; Schnabel, M.

2006-12-01

291

Utility of coal seams as genetic stratigraphic sequence boundaries in nonmarine basins: An example from the Gunnedah Basin, Australia: Reply  

SciTech Connect

The primary objective of our paper was to contribute to the development of more accurate techniques in stratigraphic analysis of nonmarine basin fills. Admittedly, we drew analogies from the sequence stratigraphic concepts derived in marginal-marine basin settings and aligned our concepts with those of Galloway (1989), but it is inappropriate to judge our ideas using as a template the sequence stratigraphic concepts of marginal-marine basin fills. We were not applying these existing concepts to nonmarine settings. Rather, we were proposing new concepts for the largely uncharted (with respect to sequence stratigraphic analysis) nomnarine basin settings.

Hamilton, D.S. [Univ. of Texas, Austin, TX (United States)

1995-08-01

292

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

NASA Astrophysics Data System (ADS)

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

Strozyk, Frank; Back, Stefan; Kukla, Peter

2013-04-01

293

75 FR 23582 - Annular Casing Pressure Management for Offshore Wells  

Federal Register 2010, 2011, 2012, 2013, 2014

...develop the industry standard. Offshore Operators Committee (OOC...Casing Pressure Management for Offshore Wells (74 FR 38147, July...annular casing pressure in offshore wells. (4) This final rule...Gas Extraction, and 213111, Drilling Oil and Gas Wells. For...

2010-05-04

294

Extreme Loads for an Offshore Wind Turbine using Statistical  

E-print Network

Extreme Loads for an Offshore Wind Turbine using Statistical Extrapolation from Limited Field Data,itiscommontoeithercarry out extensive simulation studies or undertake a field measurement campaign. At the Blyth offshore wind here is to estimate extreme loads for an offshore wind turbine for which the environmental and load

Manuel, Lance

295

Scour around an offshore wind turbine W.F. Louwersheimer  

E-print Network

Scour around an offshore wind turbine MSc Thesis W.F. Louwersheimer January, 2007 Delft University #12;Scour around an offshore wind turbine Delft University of Technology Ballast Nedam - Egmond iii Scour around an offshore wind turbine W.F. Louwersheimer Student number 1067419 January, 2007

Langendoen, Koen

296

REVIEW Open Access Assessing environmental impacts of offshore wind  

E-print Network

REVIEW Open Access Assessing environmental impacts of offshore wind farms: lessons learned and recommendations for the future Helen Bailey1* , Kate L Brookes2 and Paul M Thompson3 Abstract Offshore wind power literature and our experience with assessing impacts of offshore wind developments on marine mammals

Aberdeen, University of

297

Challenges in Predicting Power Output from Offshore Wind Farms  

E-print Network

Challenges in Predicting Power Output from Offshore Wind Farms R. J. Barthelmie1 and S. C. Pryor2 Abstract: Offshore wind energy is developing rapidly in Europe and the trend is towards large wind farms an offshore wind farm, accurate assessment of the wind resource/power output from the wind farm is a necessity

Pryor, Sara C.

298

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

E-print Network

Offshore Wind Farm Layout Optimization (OWFLO) Project: Preliminary Results Christopher N. Elkinton 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

Massachusetts at Amherst, University of

299

Wave Models for Offshore Wind Turbines Puneet Agarwal  

E-print Network

Wave Models for Offshore Wind Turbines Puneet Agarwal§ and Lance Manuely Department of Civil. These wave modeling assumptions do not adequately represent waves in shallow waters where most offshore wind for estimating loads on the support structure (monopile) of an offshore wind turbine. We use a 5MW utility

Manuel, Lance

300

Using satellite data for mapping offshore wind resources and wakes  

E-print Network

Using satellite data for mapping offshore wind resources and wakes Charlotte Bay Hasager, Merete Energy Department, Denmark Copenhagen Offshore Wind, Conference and Exhibition 26-28 October 2005, Copenhagen, Denmark #12;· Offshore winds from satellites · Wind ressource estimation · Wake estimation

301

Quantifying Offshore Wind Resources from Satellite Wind Maps  

E-print Network

Quantifying Offshore Wind Resources from Satellite Wind Maps: Study Area the North Sea C. B National Laboratory, Roskilde, Denmark Offshore wind resources are quantified from satellite synthetic the spatial extent of the wake behind large offshore wind farms. Copyright © 2006 John Wiley & Sons, Ltd

Pryor, Sara C.

302

Ris National Laboratory Satellite SAR applied in offshore wind  

E-print Network

Risø National Laboratory Satellite SAR applied in offshore wind ressource mapping: possibilities is to quantify the regional offshore wind climate for wind energy application based on satellite SAR ·Study of 85SAR(m/s) Hasager, Dellwik, Nielsen and Furevik, 2004, Validation of ERS-2 SAR offshore wind-speed maps

303

Electric power from offshore wind via synoptic-scale interconnection  

E-print Network

Electric power from offshore wind via synoptic-scale interconnection Willett Kemptona,1 , Felipe M regional estimate, Kempton et al. (2) calculated that two-thirds of the offshore wind power off the U in the U.S. Atlantic region is already underway. Fig. 1 shows as black squares offshore wind developments

Firestone, Jeremy

304

Assessing Novel Foundation Options for Offshore Wind Turbines  

E-print Network

Assessing Novel Foundation Options for Offshore Wind Turbines B.W. Byrne, BE(Hons), BCom, MA, DPhil G.T. Houlsby, MA, DSc, FREng, FICE Oxford University, UK SYNOPSIS Offshore wind farms, and of these wind power is the only one to be exploited on a commercial scale at present. Three major offshore

Byrne, Byron

305

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

306

Review report 2004 The Danish Offshore Wind Farm  

E-print Network

- 1 - Review report 2004 The Danish Offshore Wind Farm Demonstration Project: Horns Rev and Nysted Offshore Wind Farms Environmental impact assessment and monitoring Prepared for The Environmental Group By Elsam Engineering and ENERGI E2 October 2005 #12;- 2 - Review Report 2004 The Danish Offshore Wind Farm

307

Hydroacoustic Monitoring of Fish Communities in Offshore Wind Farms  

E-print Network

#12;Hydroacoustic Monitoring of Fish Communities in Offshore Wind Farms Annual Report 2004 Horns Rev Offshore Wind Farm Published: May 2005 Prepared by: Christian B. Hvidt Lars Brünner Frank Reier farms Horns Rev Offshore Wind Farm 2004 2519-03-003-rev3.doc TABLE OF CONTENTS PAGE 1. Introduction

308

Ris-R-1407(EN) Efficient Development of Offshore  

E-print Network

, Roskilde April 2003 #12;Abstract Europe has large offshore wind energy potential that is poised energy supply. Offshore wind energy developments are underway in many European countries with planned the impact of thermal flows, roughness and orography on offshore wind speeds. The model hierarchy developed

309

Offshore safety case approach and formal safety assessment of ships  

Microsoft Academic Search

Problem: Tragic marine and offshore accidents have caused serious consequences including loss of lives, loss of property, and damage of the environment. Method: A proactive, risk-based “goal setting” regime is introduced to the marine and offshore industries to increase the level of safety. Discussion: To maximize marine and offshore safety, risks need to be modeled and safety-based decisions need to

J Wang

2002-01-01

310

E2I EPRI Assessment Offshore Wave Energy Conversion Devices  

E-print Network

E2I EPRI Assessment Offshore Wave Energy Conversion Devices Report: E2I EPRI WP ­ 004 ­ US ­ Rev 1 #12;E2I EPRI Assessment - Offshore Wave Energy Conversion Devices Table of Contents Introduction Assessment - Offshore Wave Energy Conversion Devices Introduction E2I EPRI is leading a U.S. nationwide

311

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

312

Seismic sequence stratigraphy and depositional history of the Pliocene-Pleistocene fans in the Ganal Block, offshore Kutai Basin, Indonesia  

NASA Astrophysics Data System (ADS)

A seismic stratigraphy study was conducted to develop a stratigraphic framework for Pliocene-Pleistocene sediments in the Ganal area, Makassar Strait, Indonesia. The study area, physiographically located in the continental slope of the offshore Kutai basin, is very attractive for deep water sequence stratigraphy analysis. The sediment interval exhibits a series of geologic features of deep water sedimentation such as a submarine fan associated with canyons and channels-levees complex. Analysis of over 4000 km of multichannel seismic data serves to detail documentation of such features and the stratigraphic evolution of the area. On the basis of their termination patterns, two types of significant stratigraphic surfaces, unconformity and flooding surfaces, can be identified as seismic boundaries on the seismic sections. The unconformity surfaces can be recognized by erosional, truncation, and onlap termination patterns. The distribution of these surface can be correlated in the area from the slope to the basin floor, which is commonly associated with scour channels. The flooding surfaces can be recognized by downlap termination patterns of the younger layers into the older strata below. Both of these surfaces provide important information to reveal the depositional history of the deep water sedimentation in the study area. Regional seismic profiles indicate that the Pliocene-Pleistocene sediments were deposited in the slope to basin floor setting, from the west to the east respectively. The structural and stratigraphic analysis suggests that this basin configuration strongly influenced the distribution and thickness of the seismic sequences and stratigraphic development of the Pliocene-Pleistocene sedimentary succession. Isochron maxima correspond to the depocenters that are close to sedimentary pathways and are associated with submarine channels and canyons. The isochron patterns show that depocenters and sediment pathways during deposition of the Pliocene-Pleistocene interval coincide with regional basin setting. Six seismic sequences have been identified within the Pliocene-Pleistocene interval. Each sequence consists of lowstand deposits that can be recognized by its seismic facies units. The seismic characteristics vary from sequence to sequence as well as within lowstand system tracts. Lowstand features including submarine canyons, channels, and fan lobes have been identified and mapped. Identification of these features substantially reduces the reservoir risk associated with deep water depositional environments. The canyons, channels, and fan lobes in the study area were superimposed and presented in the composite map and served as a good model and unique example for deep water sedimentation. Finally, a depositional model of lowstand deposits for the study area has been established and may play an important role in future exploration and development in this region and elsewhere in the world.

Alam, Syamsu

313

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

SciTech Connect

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

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

1996-08-01

314

Application of low density foam pigs offshore Brazil  

SciTech Connect

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

Lima, P.C.R.; Alves, S.J. [Petrobras, Rio de Janeiro (Brazil)

1995-12-31

315

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

316

Chapter 14 The Atlantic Margin Basins of North America  

Microsoft Academic Search

The Atlantic margin of North America represents the classic “Atlantic-type” continental margin, notably the margin off the east coast of the United States, which was the site of five deep offshore stratigraphic test holes wells (the Continental Offshore Stratigraphic Test, or COST series) drilled in 1976–1979 on the Georges Bank, the Baltimore Canyon Trough, and the Southeast Georgia Embayment. Data

Andrew D. Miall; Hugh R. Balkwill; Jock McCracken

2008-01-01

317

Sequence of Tectonic Deformation in the History of Venus: Evidence from Global Stratigraphic Relations  

NASA Astrophysics Data System (ADS)

Analysis of local and regional stratigraphic relationships has permitted the assessment of the nature of tectonic structures and their distribution throughout the observed history of Venus. We find that regional shortening characteristic of the tessera gives way to widespread distributed extension, followed by compression (peaking during and just following the emplacement of the majority of the volcanic plains), which wanes in significance with time (ridge belts ->wrinkle ridges). Focused extensional deformation (rift systems and fracture belts) dominates the later stages of geologic history. These trends appear well-established from a stratigraphic point of view and provide guidelines and constraints on models for Venus geologic history.

Head, J. W.; Basilevsky, A. T.

1996-03-01

318

Stratigraphic Profiles for Selected Hanford Site Seismometer Stations and Other Locations  

SciTech Connect

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

Last, George V.

2014-02-01

319

Stratigraphic relationships in Woodbine-Eagleford and Sub-Clarksville sandstones, IDS field, Brazos County, Texas  

E-print Network

STRATIGRAPHIC RELATIONSHIPS IN WOODBINE-EAGLEFORD AND SUB-CLARKSVILLE SANDSTONES, IDS FIELD, BRAZOS COUNTY, TEXAS A Thesis by RON LEE BROGDON Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1990 Major Subject: Geology STRATIGRAPHIC RELATIONSkIIPS IN WOODBINF. -EAGLEI ORD AND SUB-CLARKSVILI. E SANDSTONES, IDS FIELD, BRAZOS COIJN"I y, 'I'LXAS A Thesis by RON LEE BROGDON Approved...

Brogdon, Ron Lee

2012-06-07

320

Large enigmatic crater structures offshore southern California  

Microsoft Academic Search

Digital mosaics of swath and conventional bathymetry data reveal large, distinct near-circular crater structures in the Inner Continental Borderland offshore southern California. Two have maximum crater diameters that exceed 30 km and a third has a crater diameter of approximately 12 km. All three features exhibit the morphology of large complex craters (raised outer rim, ring moat and central uplift)

Mark R. Legg; Craig Nicholson; Chris Goldfinger; Randall Milstein; Marc J. Kamerling

2004-01-01

321

Planning and evaluation parameters for offshore complexes  

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

322

Solar power satellite offshore rectenna study  

NASA Technical Reports Server (NTRS)

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

1980-01-01

323

Competitive Bidding for Offshore Petroleum Leases  

Microsoft Academic Search

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

Douglas K. Reece

1978-01-01

324

Offshore Investments by Colleges Draw Scrutiny  

ERIC Educational Resources Information Center

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

Fain, Paul; Wolverton, Brad

2007-01-01

325

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

326

Distributed computer control for an offshore platform  

Microsoft Academic Search

Mobil Exploration Norway Inc.'s Condeep offshore platform Statfjord A, in the North Sea, which has facilities for drilling, production, crude oil storage, gas compression, and custody-transfer to tankers through an articulated loading platform, as well as a 60 Mw electrical generator and distribution system, is fully instrumented via a Supervisory Control and Data Acquisition (SCADA) system. The SCADA system is

1978-01-01

327

Assessing offshore wind resources: An accessible methodology  

Microsoft Academic Search

This paper describes a method for assessing the electric production and value of wind resources, specifically for the offshore environment. Three steps constitute our method. First, we map the available area, delimiting bathymetric areas based on turbine tower technology, then assess competing uses of the ocean to establish exclusion zones. From exclusion zones, bathymetry, and turbine tower water depth limitations,

Amardeep Dhanju; Phillip Whitaker; Willett Kempton

2008-01-01

328

Assessing offshore wind resources: An accessible methodology  

Microsoft Academic Search

This paper describes a method for assessing the electric production and value of wind resources, specifically for the offshore environment. Three steps constitute our method. First, we map the available area, delimiting bathymetric areas based on turbine tower technology, then assess competing uses of the ocean to establish exclusion zones. From exclusion zones, bathymetry, and turbine tower water depth limitations,

Amardeep Dhanju; Phillip Whitaker; Willett Kempton

2007-01-01

329

Marine Fisheries On the cover: Offshore  

E-print Network

Marine Fisheries ~~WD~W On the cover: Offshore charter boats at Islamorada, Fla. See the article Fish Technology and Marine Pollution 32 u.s. DEPARTMENT OF COMMERCE Malcolm Baldrige, Secretary NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION John V. Byrne, Administrator National Marine Fisheries

330

CHOOSING OFFSHORE PIPELINE ROUTES: PROBLEMS AND SOLUTIONS  

EPA Science Inventory

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

331

Sea Stars Underwater Offshore Northern California  

USGS Multimedia Gallery

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

332

Fish Swimming Underwater Offshore Northern California  

USGS Multimedia Gallery

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

333

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

SciTech Connect

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

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

1991-03-01

334

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

SciTech Connect

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

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

2014-07-01

335

Testing  

MedlinePLUS

... curesma.org > learn about sma > causes & diagnoses > testing Testing An SMA diagnosis must be confirmed through genetic ... and must be identified through further testing. Prenatal Testing Prenatal testing is used to determine if a ...

336

Divergent evolutionary processes associated with colonization of offshore islands.  

PubMed

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

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

2013-10-01

337

Sequence stratigraphic-structural analysis of the East Midlands Carboniferous oil field, UK: Implications for fluvial reservoir models  

Microsoft Academic Search

The integration of seismic, well log and core data from, the Scampton North and Welton oil fields, Lincolnshire, UK, has enabled the development of a sequence stratigraphic-structural model for late Namurian and early Westphalian fluvial reservoirs. The tectonic and sequence stratigraphic setting is remarkably similar to that in the Southern North Sea which extends more than 250 km to the

J. F. Aitken; D. G. Quirk

1996-01-01

338

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

339

Structural styles of the paradox basin: Something to consider in a basin dominated by stratigraphic traps  

Microsoft Academic Search

The Paradox basin has produced a considerable amount of oil and gas from Pennsylvanian and Mississippian reservoirs. Most of the production has been from stratigraphic traps associated with subtle rejuvenated basement structures. Only the Blanding sub-basin and west flank of the salt anticlines (Lisbon Valley to Salt Wash fields) have been explored in sufficient quantity to classify as the mature

1993-01-01

340

The Boscan Field-Venezuela's giant stratigraphic trap with a complex history  

Microsoft Academic Search

The Boscan Field lies in the northwest quadrant of the Maracaibo Basin, Venezuela. It is a large stratigraphic trap that has produced more than 800 million barrels of heavy oil since 1946, principally from Eocene fluvial-deltaic clastic reservoirs. These are faulted, folded, and are truncated by a pre-Oligocene unconformity. The geochronology of the Boscan Field has been interpreted as follows:

D. C. Swanson; J. Jaimes; C. Valdez; B. Pirela; F. Puche; D. Rojas; E. Moya

1993-01-01

341

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

Microsoft Academic Search

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

Susan M. Kidwell

1989-01-01

342

3-D numerical seismic stratigraphic model generated from a highly anisotropic and wide- meshed survey grid  

Microsoft Academic Search

Recently, 55 high-resolution seismic sections were collected by the Geological Survey of Canada to map the Quaternary sedimentary succession over an area of 7600 km2 in the St. Lawrence Estuary (eastern Canada). To better understand the geometrical relationships between these various units and to document the impact of the bedrock topography on the Quaternary basin infill, a numerical seismic stratigraphic

K. Bédard; M. J. Duchesne; N. Pinet; A. Bolduc

2007-01-01

343

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

344

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

345

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

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

346

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

347

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

E-print Network

). Initially these sites were investigated for their abundance of Middle Palaeolithic archaeological on the Indian subcontinent where the YTT was reported. The ash bed forms a discontinuous layer stretching for over 30 km along the river. Here we report on the stratigraphic contexts of YTT ash layers in alluvial

Boyer, Edmond

348

The K\\/T boundary at Beloc (Haiti): Compared stratigraphic distributions of the boundary markers  

Microsoft Academic Search

At Beloc, Haiti the Cretaceous-Tertiary boundary (KTB) is characterized by a spherule bed containing glass particles. These particles are considered by some authors as remains of tektites resulting from a nearby impact. However, because of the stratigraphic complexity of the Beloc sections the genetic link between the KTB cosmic event and the spherule bed is not obvious. In this paper,

Hugues Leroux; Robert Rocchia; Laurence Froget; Xavier Orue-Etxebarria; Jean-Claude Doukhan; Eric Robin

1995-01-01

349

The stratigraphic sequence of volcanic and sedimentary units in the north polar region of Mars  

Microsoft Academic Search

Based on photogeologic mapping of Viking Orbiter images of Mars, four distinct informal stratigraphic units can be defined for the region north of 70 N latitude. They are: (1) bulbous plains, (2) mantled plains, (3) dune deposits, and (4) layered deposits\\/perennial ice. The bulbous plains unit underlies all other north polar units and represents a sub-unit of the mottled cratered

M. E. Botts

1980-01-01

350

OCEANOGRAPHY Stratigraphic Distribution of Amino Acids in Peats from Cedar Creek  

E-print Network

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

Minnesota, University of

351

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

352

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

353

The offshore record of variable Cenozoic sediment flux from Western Scandinavia  

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

354

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

NASA Astrophysics Data System (ADS)

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

Clift, P. D.; Zheng, H.

2013-12-01

355

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

SciTech Connect

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

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

1983-02-01

356

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

SciTech Connect

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

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

1983-02-01

357

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

358

Offshore distributional patterns of Hawaiian fish larvae  

Microsoft Academic Search

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

J. M. Leis; J. M. Miller

1976-01-01

359

Automatic welding comes of age. [Offshore  

Microsoft Academic Search

Automatic pipe welding systems today fall into three main categories: gas metal arc welding, gas-tungsten arc welding, and flash-butt welding. The first automatic welding devices used offshore were the CRC and H.C. Price systems. Both use gas metal arc welding with a consumable steel filler wire. The recently developed McDermott flash-butt welding system is described. (DLC)

D. L. Jr

1981-01-01

360

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

361

Designing Australia's North West Shelf offshore pipeline  

SciTech Connect

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

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

1984-05-07

362

Caisson shield for arctic offshore production platform  

SciTech Connect

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

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

1985-03-12

363

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

364

Integration of offshore wind farms through high voltage direct current networks  

NASA Astrophysics Data System (ADS)

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

Livermore, Luke

365

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

PubMed

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

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

2010-09-01

366

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

SciTech Connect

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

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

2012-11-01

367

An artificial intelligence technique for automating seismic stratigraphic interpretation  

NASA Astrophysics Data System (ADS)

Studying the character of reflected seismic wavelets may reveal facts about the stratigraphy of the reflector. Computers can aid humans in this task by revealing structural similarities between various wavelets. The relational tree is a good way to represent a waveform's global structure. By representing a waveform as a relational tree, processing it symbolically, and clustering the processed trees, a seismic wave form recognition system can be constructed. The symbolic processing is based on a tree transformation. An objective function, which measures the effectiveness of such a transformation, utilizes the ratio of between-cluster to within-cluster scatter. The action of a tree transformation applied to tree spaces is the same as linear discriminants applied to feature spaces. When tested on simulated seismic data, the relational tree waveform recognition system performs well at high signal-to-noise ratios.

Shaw, Scott W.; Defigueiredo, Rui J.

1986-11-01

368

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

369

26th Annual offshore technology conference: 1994 Proceedings  

SciTech Connect

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

Not Available

1994-01-01

370

Horns Rev Offshore Wind Farm Environmental Impact Assessment  

E-print Network

Horns Rev Offshore Wind Farm Environmental Impact Assessment of Sea Bottom and Marine Biology #12 Design ApS 01.03.2000 #12;Bio/consult A/S Horns Rev. Offshore Wind Farm Doc. No. 1680-1-02-03-003 rev. 1........................................................................................................................................................... 36 #12;Bio/consult A/S ELSAM Horns Rev. Offshore Wind Farm Doc. No. 1680-1-02-03-003 rev. 1 Page 4

371

The submerged offshore breakwater and its effects on seafloor topography  

E-print Network

/B for the emergent offshore breakwater. It has been postulated that tombolo formation cannot occur in the case of the submerged offshore breakwater. However, the spit-growth/relative d1stance from shore relationship is expected to be similar. The beach...THE SUBMERGED OFFSHORE BREAKWATER AND ITS EFFECTS ON SEAFLOOR TOPOGRAPHY A Thesis by JAMES RUSSELL TALLENT Submitted to the Graduate College of Texas AGM University in partial fulfillment of the requirements for the degree of MASTER...

Tallent, James Russell

2012-06-07

372

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

SciTech Connect

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

Jonkman, J.; Musial, W.

2010-12-01

373

Successful application of 3-D seismic coherency models to predict stratigraphy, offshore eastern Trinidad  

SciTech Connect

Stratigraphy in the Columbus Basin of Trinidad & Tobago, as in most clastic basins, is characterized by episodes of shelf progradation and retrogradation in response to shifting shorelines. Amoco has developed a new 3-D discontinuity algorithm that is useful for delineating faults and stratigraphic features. This technique can be used to demarcate more high-quality, sand prone reservoir intervals, based on the density driven impedance differences between sand and shale in the basin. These differences generate 3-D coherency variations that can be horizon-slice mapped to illustrate migrating depocenters through time. Horizon based slices of 3-D seismic data were taken in the East Mayaro area, offshore eastern Trinidad. These slices showed a boundary between high and low 3-D coherence areas that migrated to the west with increasing depth across the study area. This information was combined with existing well data that reflected deep marine, laminated sands and shales associated with the more eastward low coherence areas. Predictions were made employing a geologic model that suggested the presence of time-equivalent, higher quality sands deposited in a shelf environment to the west. The prediction was successful with subsequent wells encountering high quality reservoir sands of >450 feet (140 meters). The presence of reservoir sands, favorable structure and migration history combined to result in a very successful discovery.

Ortmann, K.A.; Wood, L.J.

1995-12-31

374

Mineralogy and geochemistry of. delta. sup 13 C-depleted carbonates in offshore Trinidad  

SciTech Connect

{delta}{sup 13}C records from the fine fraction (< 63 {mu}m) of well cuttings provide an important tool for detecting stratigraphic intervals that derive a stable isotopic signal from authigenic carbonates. The purpose of this study is to evaluate the mineralogy and geochemistry of the authigenic carbonates responsible for a significantly depleted interval in a {delta}{sup 13}C fine-fraction record for the Pliocene-Pleistocene deposits of offshore Trinidad. To achieve this goal, the coarse fraction (> 63 {mu}m) of the well cuttings are examined and analyzed. The {delta}{sup 13}C-depletion event in the fine-fraction record corresponds to a carbonate-cemented sand with extremely depleted {delta}{sup 13}C values of {minus}25 to {minus}58 {per thousand} (PDB). Calcite with 11 to 14 mole % MgCO{sub 3} forms equant spherulitic crystals, which, when polished and viewed with reflected light, display several growth stages. Dolomite cement found in one sample does not have growth stages that are recognizable by similar means. Both types of cement have extremely depleted carbon isotope values and {delta}{sup 13}C values between 0.3 and 1.9 {per thousand} (PDB). The stable isotope data suggest that the Trinidad shelf during the Pliocene-Pleistocene was a site of carbonate cementation either at the sediment/water interface or under shallow burial where pore-water conditions were strongly influenced by the oxidation of methane.

Falls, W.F.; Williams, D.F. (Univ. of South Carolina, Columbia (USA))

1990-05-01

375

The outsourcing and offshoring competitive landscape and its uncertainties  

E-print Network

The outsourcing and offshoring competitive landscape is rapidly and constantly evolving, presenting new challenges and opportunities for providers and customers alike. Outsourcing providers are pressured to increase the ...

Sultan, Ziad R. (Ziad Raymond)

2005-01-01

376

Integral sliding mode control for offshore steel jacket platforms  

NASA Astrophysics Data System (ADS)

This paper is concerned with robust integral sliding mode control for an offshore steel jacket platforms subject to nonlinear wave-induced force and parameter perturbations. A robust integral sliding mode controller is designed to stabilize the dynamic model of the offshore steel jacket platform. It is shown through simulation results that the robust integral sliding mode control scheme can reduce the internal oscillations of the offshore steel jacket platform dramatically; and the performance of the offshore steel jacket platform under the robust integral sliding mode control scheme is better than the ones under the nonlinear control scheme and the dynamic output feedback control scheme.

Zhang, Bao-Lin; Han, Qing-Long; Zhang, Xian-Ming; Yu, Xinghuo

2012-07-01

377

Operational Impacts of Large Deployments of Offshore Wind (Poster)  

SciTech Connect

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

Ibanez, E.; Heaney, M.

2014-10-01

378

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

379

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

380

Sequence stratigraphy of the Orange basin, western offshore South Africa  

Microsoft Academic Search

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

1991-01-01

381

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

NASA Astrophysics Data System (ADS)

This study on the characteristics of fouling communities in offshore areas south of Hainan Island, northern South China Sea, was conducted at four sites there. At each station, test panels on iron frames were hung on the mooring system at different depths. Data on biofouling were mainly obtained by examination of the fouled test panels. Organisms attached to buoys and anchors were scraped off and examined also. The results showed that the thickness and biomass of marine growth that increased the fluid loading on offshore installations depended to a large extent on hard foulers, i. e. mollusks and acorn barnacles. Algae, hydroids, stalked barnacles and bryozoans were important fouling species. The occurrence frequency and biomass of acorn barnacles decreased with increasing distance from the shore.

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

2000-06-01

382

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

383

Stratigraphic Subdivision of the Transvaal Dolomite from ERTS imagery. [South Africa  

NASA Technical Reports Server (NTRS)

ERTS imagery has revealed the presence of broad stratigraphic subdivisions in the previously undifferentiated Transvaal Dolomite of the western Tranvaal, Republic of South Africa. While detailed field mapping in areas of good outcrop, as well as borehole logging has recently led to the recognition of a stratigraphy in the Transvaal Dolomite of the central Transvaal, poor outcrop in the western Transvaal has to date prevented this. The ERTS-imagery, however, clearly reveals the presence of six, and in the far west seven, distinct stratigraphic zones extending along strike for a distance of at least 200 km. The investigation clearly demonstrates the potential applications of ERTS-imagery in geological studies, even in a country where the geology is supposedly well known.

Grootenboer, J.; Eriksson, K.; Truswell, J.

1974-01-01

384

The stratigraphic sequence of volcanic and sedimentary units in the north polar region of Mars  

NASA Technical Reports Server (NTRS)

Based on photogeologic mapping of Viking orbiter images of Mars, four distinct informal stratigraphic units are defined for the region north of 70 degrees N latitude. They are: (a) bulbous plains, (b) mantled plains, (c) dune deposits, and (d) layered deposits/perennial ice. Background information on the Martian polar caps is provided from telescopic observation, Mariner mission results, and Viking mission results (August 1976-November 1978). A description, and an interpretation and distribution of the stratigraphic units are presented. Surface winds, which were determined from dune orientations, and discussed and implications for the source of circumpolar dune materials are delineated. A list of the Viking Orbiter imagery used in the research, the computer programs for crater size frequency distributions, and the crater size frequency data are presented.

Botts, M. E.

1980-01-01

385

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

NASA Astrophysics Data System (ADS)

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

O'Reilly, Christopher M.

386

75 FR 60097 - National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling  

Federal Register 2010, 2011, 2012, 2013, 2014

...Deepwater Horizon Oil Spill and Offshore Drilling AGENCY: Department of Energy...Deepwater Horizon Oil Spill and Offshore Drilling (the Commission). The Commission...any oil spills associated with offshore drilling in the future. The...

2010-09-29

387

46 CFR 11.468 - Officer endorsements for mobile offshore drilling units.  

Code of Federal Regulations, 2012 CFR

...Officer endorsements for mobile offshore drilling units. 11.468 Section...Officer endorsements for mobile offshore drilling units. Officer endorsements for service on mobile offshore drilling units (MODUs)...

2012-10-01

388

40 CFR 112.11 - Spill Prevention, Control, and Countermeasure Plan requirements for offshore oil drilling...  

Code of Federal Regulations, 2013 CFR

...Countermeasure Plan requirements for offshore oil drilling, production, or workover...Countermeasure Plan requirements for offshore oil drilling, production, or workover...the owner or operator of an offshore oil drilling, production, or...

2013-07-01

389

40 CFR 112.11 - Spill Prevention, Control, and Countermeasure Plan requirements for offshore oil drilling...  

Code of Federal Regulations, 2011 CFR

...Countermeasure Plan requirements for offshore oil drilling, production, or workover...Countermeasure Plan requirements for offshore oil drilling, production, or workover...the owner or operator of an offshore oil drilling, production, or...

2011-07-01

390

77 FR 71607 - Mobile Offshore Drilling Unit (MODU) Electrical Equipment Certification Guidance  

Federal Register 2010, 2011, 2012, 2013, 2014

...USCG-2012-0839] Mobile Offshore Drilling Unit (MODU) Electrical Equipment...on foreign-flagged Mobile Offshore Drilling Units (MODUs) that have never...Construction and Equipment of Mobile Offshore Drilling Units (2009 IMO MODU...

2012-12-03

391

40 CFR 112.11 - Spill Prevention, Control, and Countermeasure Plan requirements for offshore oil drilling...  

Code of Federal Regulations, 2014 CFR

...Countermeasure Plan requirements for offshore oil drilling, production, or workover...Countermeasure Plan requirements for offshore oil drilling, production, or workover...the owner or operator of an offshore oil drilling, production, or...

2014-07-01

392

75 FR 65309 - National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling  

Federal Register 2010, 2011, 2012, 2013, 2014

...Deepwater Horizon Oil Spill and Offshore Drilling AGENCY: Department of Energy...Deepwater Horizon Oil Spill and Offshore Drilling (the Commission). The Commission...any oil spills associated with offshore drilling in the future. The...

2010-10-22

393

76 FR 39885 - Risk-Based Targeting of Foreign Flagged Mobile Offshore Drilling Units (MODUs)  

Federal Register 2010, 2011, 2012, 2013, 2014

...Targeting of Foreign Flagged Mobile Offshore Drilling Units (MODUs) AGENCY: Coast...Targeting of Foreign Flagged Mobile Offshore Drilling Units (MODUs). This policy...every foreign-flagged mobile offshore drilling unit (MODU) must undergo...

2011-07-07

394

75 FR 69652 - National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling  

Federal Register 2010, 2011, 2012, 2013, 2014

...Deepwater Horizon Oil Spill and Offshore Drilling AGENCY: Department of Energy...Deepwater Horizon Oil Spill and Offshore Drilling (the Commission). The Commission...any oil spills associated with offshore drilling in the future. The...

2010-11-15

395

40 CFR 112.11 - Spill Prevention, Control, and Countermeasure Plan requirements for offshore oil drilling...  

Code of Federal Regulations, 2012 CFR

...Countermeasure Plan requirements for offshore oil drilling, production, or workover...Countermeasure Plan requirements for offshore oil drilling, production, or workover...the owner or operator of an offshore oil drilling, production, or...

2012-07-01

396

46 CFR 2.10-130 - Fees for examination of foreign mobile offshore drilling units.  

Code of Federal Regulations, 2014 CFR

...Fees for examination of foreign mobile offshore drilling units. 2.10-130 Section 2...Fees for examination of foreign mobile offshore drilling units. Each foreign mobile offshore drilling unit must pay: (a) For...

2014-10-01

397

46 CFR 11.468 - Officer endorsements for mobile offshore drilling units.  

Code of Federal Regulations, 2013 CFR

...Officer endorsements for mobile offshore drilling units. 11.468 Section...Officer endorsements for mobile offshore drilling units. Officer endorsements for service on mobile offshore drilling units (MODUs)...

2013-10-01

398

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Deepwater Horizon Oil Spill and Offshore Drilling By the authority vested in me...Deepwater Horizon Oil Spill and Offshore Drilling (the ``Commission...oil spills associated with offshore drilling, taking into...

2010-05-26

399

46 CFR 2.10-130 - Fees for examination of foreign mobile offshore drilling units.  

Code of Federal Regulations, 2013 CFR

...Fees for examination of foreign mobile offshore drilling units. 2.10-130 Section 2...Fees for examination of foreign mobile offshore drilling units. Each foreign mobile offshore drilling unit must pay: (a) For...

2013-10-01

400

46 CFR 2.10-130 - Fees for examination of foreign mobile offshore drilling units.  

Code of Federal Regulations, 2010 CFR

...Fees for examination of foreign mobile offshore drilling units. 2.10-130 Section 2...Fees for examination of foreign mobile offshore drilling units. Each foreign mobile offshore drilling unit must pay: (a) For...

2010-10-01

401

46 CFR 2.10-130 - Fees for examination of foreign mobile offshore drilling units.  

Code of Federal Regulations, 2012 CFR

...Fees for examination of foreign mobile offshore drilling units. 2.10-130 Section 2...Fees for examination of foreign mobile offshore drilling units. Each foreign mobile offshore drilling unit must pay: (a) For...

2012-10-01

402

33 CFR 147.T08-849 - DEEPWATER HORIZON Mobile Offshore Drilling Unit Safety Zone.  

Code of Federal Regulations, 2010 CFR

...false DEEPWATER HORIZON Mobile Offshore Drilling Unit Safety Zone. 147.T08-849...T08-849 DEEPWATER HORIZON Mobile Offshore Drilling Unit Safety Zone. (a) Location...DEEPWATER HORIZON, a Mobile Offshore Drilling Unit (MODU), that...

2010-07-01

403

76 FR 78938 - Carpinteria Offshore Field Redevelopment Project-Developmental Drilling Into the Carpinteria...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Management Carpinteria Offshore Field Redevelopment...Developmental Drilling Into the Carpinteria Offshore Field Oil and Gas...Description of the Area Drilling will take place from...Channel, 3.7 miles offshore of the City of...

2011-12-20

404

75 FR 47584 - National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling  

Federal Register 2010, 2011, 2012, 2013, 2014

...Deepwater Horizon Oil Spill and Offshore Drilling AGENCY: Department of Energy...Deepwater Horizon Oil Spill and Offshore Drilling (the Commission). The Commission...any oil spills associated with offshore drilling in the future. The...

2010-08-06

405

75 FR 56526 - National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling  

Federal Register 2010, 2011, 2012, 2013, 2014

...Deepwater Horizon Oil Spill and Offshore Drilling AGENCY: Department of Energy...Deepwater Horizon Oil Spill and Offshore Drilling (the Commission). The Commission...any oil spills associated with offshore drilling in the future. The...

2010-09-16

406

40 CFR 112.11 - Spill Prevention, Control, and Countermeasure Plan requirements for offshore oil drilling...  

Code of Federal Regulations, 2010 CFR

...Countermeasure Plan requirements for offshore oil drilling, production, or workover...Countermeasure Plan requirements for offshore oil drilling, production, or workover...the owner or operator of an offshore oil drilling, production, or...

2010-07-01

407

46 CFR 2.10-130 - Fees for examination of foreign mobile offshore drilling units.  

Code of Federal Regulations, 2011 CFR

...Fees for examination of foreign mobile offshore drilling units. 2.10-130 Section 2...Fees for examination of foreign mobile offshore drilling units. Each foreign mobile offshore drilling unit must pay: (a) For...

2011-10-01

408

46 CFR 11.468 - Officer endorsements for mobile offshore drilling units.  

Code of Federal Regulations, 2011 CFR

...Officer endorsements for mobile offshore drilling units. 11.468 Section...Officer endorsements for mobile offshore drilling units. Officer endorsements for service on mobile offshore drilling units (MODUs)...

2011-10-01

409

46 CFR 11.468 - Officer endorsements for mobile offshore drilling units.  

Code of Federal Regulations, 2010 CFR

...Officer endorsements for mobile offshore drilling units. 11.468 Section...Officer endorsements for mobile offshore drilling units. Officer endorsements for service on mobile offshore drilling units (MODUs)...

2010-10-01

410

UNDERLYING MOTIVATIONS FOR DELAWARE PUBLIC PARTICIPATION IN SUPPORT OF OFFSHORE WIND  

E-print Network

UNDERLYING MOTIVATIONS FOR DELAWARE PUBLIC PARTICIPATION IN SUPPORT OF OFFSHORE WIND: IMPLICATIONS PARTICIPATION IN SUPPORT OF OFFSHORE WIND: IMPLICATIONS FOR STATE ENERGY POLICY by Jacqueline D Piero Approved ................................................................................................. 3 Offshore wind: a new option in the United States.............................................. 4

Firestone, Jeremy

411

78 FR 16529 - Notice of Determination of No Competitive Interest, Offshore Virginia  

Federal Register 2010, 2011, 2012, 2013, 2014

...of No Competitive Interest, Offshore Virginia AGENCY: Bureau of...Shelf (OCS) Research Lease Offshore Virginia...the Outer Continental Shelf Offshore Virginia, that BOEM published...to acquire an OCS lease for wind energy research...

2013-03-15

412

76 FR 14681 - Commercial Leasing for Wind Power on the Outer Continental Shelf (OCS) Offshore Massachusetts...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Interest (RFI) in Commercial Wind Energy Leasing Offshore Massachusetts...period on the RFI in Commercial Wind Energy Leasing Offshore Massachusetts...Register the RFI in Commercial Wind Energy Leasing Offshore...

2011-03-17

413

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

Code of Federal Regulations, 2014 CFR

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

2014-07-01

414

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

415

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

416

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

417

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

418

The Lanyard field, a structural-stratigraphic trap, Denver basin, Colorado  

Microsoft Academic Search

Cretaceous sandstones are oil and gas productive throughout a large area in the Denver basin. The Lanyard field is a structural-stratigraphic trap which has produced in excess of 2,388,000 bbls of oil and 4.1 Bcf of gas from the D Sandstone. Productive sandstones are interpreted to be channel deposits on the basis of subsurface mapping and core examination. Seven Cretaceous

Sonnenberg

1982-01-01

419

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

420

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

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

421

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

422

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

423

Erosion of hard surface coatings for use in offshore gate valves  

Microsoft Academic Search

This paper describes the work carried out in assessing the performance of hard chromium, electroless nickel composite and two HVOF tungsten carbide coatings as candidate hard surface coatings for use in offshore gate valves. The coatings were erosion tested in a slurry jet facility and their performance compared with a D-gun 86WC–10Co–4Cr coating that is currently widely used in service.

D. W. Wheeler; R. J. K. Wood

2005-01-01

424

Architecture of delta plain deposits in a sequence stratigraphic framework: The upper carboniferous of eastern Kentucky  

SciTech Connect

Fluvio-deltaic sequences of the Upper Carboniferous Four Corners formation in the Appalachian basin of eastern Kentucky are reinterpreted using sequence stratigraphic techniques. A data set of correlated large-scale road-cut exposures and continuous coring records was processed and used in a three-dimensional (3-D) reservoir modeling program in order to obtain a detailed model of the 3-D architecture of the stratigraphic succession. The architecture of the sediment bodies is related to the position within the depositional system. The 140-m-thick Four Corners formation comprises three facies associations, which are cyclically organized. The boundaries between the cycles are formed by erosive surfaces, and are developed as lowstand incised valleys. A subsequent base-level rise resulted in the infilling of these valleys with amalgamated stacked channel deposits (early transgressive systems tract). Flood plain aggradation and extensive peat accumulation occurred during progressive rise (transgressive systems tracts). Marine flooding took place in the upper part of the sequence (late transgressive systems tract) and was followed by prograding mouthbar deposits during base-level stabilization (highstand). The sequence stratigraphic approach to these Upper Carboniferous cyclothems highlights the importance of relative sea level changes and may improve our understanding of sediment body geometries and architecture, resulting in more accurate predictive geological reservoir models of the subsurface.

Buter, S.J. (Delft Univ. of Technology (Netherlands))

1993-09-01

425

Stratigraphic Context of Old Crow Tephra, Holitna Lowland, Interior Southwest Alaska  

USGS Publications Warehouse

A thick deposit of Old Crow tephra was discovered in a bluff exposure along the middle Holitna River near the Kulukbuk Hills (61??20???N latitude, 157??10???W longitude) in interior southwest Alaska. This locality is the southwesternmost-known deposit of Old Crow tephra in Alaska. Thickness and grain-size data from this site support a source volcano in the eastern Aleutian arc. Pleistocene stratigraphic sequences in the lowland are dominated by upward-fining eolian sand-sheet deposits and loess separated by organic silt. These deposits record at least two episodes of regional glaciation and an intervening nonglacial period (marine oxygen isotope stage 3, stage 5, or both). Old Crow tephra crops out near the top of the lower upward-fining eolian unit, indicating that the ash erupted near the end of an interval of periglacial eolian sedimentation. The sequence of eolian deposits that contain Old Crow tephra probably accumulated during the latter part of marine oxygen isotope stage 6, whereas the overlying eolian sequence formed during the last glaciation (stage 2). This stratigraphic position is consistent with other stratigraphic contexts for the tephra and with fission-track and thermoluminescence ages of ca. 140,000 ?? 10,000 yr B.P.

Waythomas, C.F.; Lea, P.D.; Walter, R.C.

1993-01-01

426

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

SciTech Connect

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

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

1989-05-01

427

Revised Cretaceous and Tertiary stratigraphic nomenclature in the Colville Basin, Northern Alaska  

USGS Publications Warehouse

A revised stratigraphic nomenclature is proposed for Cretaceous and Tertiary geologic units of the central and western North Slope of Alaska. This revised nomenclature is a simplified and broadly applicable scheme suitable for a suite of digital geologic quadrangle maps being prepared jointly by the U.S. Geological Survey and the Alaska Department of Natural Resources, Division of Geological and Geophysical Surveys and Division of Oil and Gas. This revised nomenclature scheme is a simplification of a complex stratigraphic terminology that developed piecemeal during five decades of geologic investigations of the North Slope. It is based on helicopter-supported geologic field investigations incorporating information from high-resolution aerial photography, satellite imagery, paleontology, reflection seismic records, and sequence stratigraphic concepts. This revised nomenclature proposes the abandonment of the Colville Group; demotion of the Nanushuk Group to formation status; abandonment of six formations (Kukpowruk, Tuktu, Grandstand, Corwin, Chandler, and Ninuluk); revision of four formations (Sagavanirktok, Prince Creek, Schrader Bluff, and Seabee); elevation of the Tuluvak Tongue of the Prince Creek Formation to formation status; revision of two members (Franklin Bluffs Member and Sagwon Member of the Sagavanirktok Formation); abandonment of eight members or tongues (Kogosukruk, Rogers Creek, Barrow Trail, Sentinel Hill, Ayiyak, Shale Wall, Niakogon, and Killik); and definition of one new member (White Hills Member of the Sagavanirktok Formation).

Mull, Charles G.; Houseknecht, David W.; Bird, Kenneth J.

2003-01-01

428

Homopolar pulse welding for offshore deep water pipelines  

SciTech Connect

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

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

1995-12-31

429

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

SciTech Connect

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

Not Available

1993-01-01

430

Arctic and offshore research. Technology status report  

SciTech Connect

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

Not Available

1984-10-01

431

Modal strain energy based structural damage localization for offshore platform using simulated and measured data  

NASA Astrophysics Data System (ADS)

Modal strain energy based methods for damage detection have received much attention. However, most of published articles use numerical methods and some studies conduct modal tests with simple 1D or 2D structures to verify the damage detection algorithms. Only a few studies utilize modal testing data from 3D frame structures. Few studies conduct performance comparisons between two different modal strain energy based methods. The objective of this paper is to investigate and compare the effectiveness of a traditional modal strain energy method (Stubbs index) and a recently developed modal strain energy decomposition (MSED) method for damage localization, for such a purpose both simulated and measured data from an offshore platform model being used. Particularly, the mode shapes used in the damage localization are identified and synthesized from only two measurements of one damage scenario because of the limited number of sensors. The two methods were first briefly reviewed. Next, using a 3D offshore platform model, the damage detection algorithms were implemented with different levels of damage severities for both single damage and multiple damage cases. Finally, a physical model of an offshore steel platform was constructed for modal testing and for validating the applicability. Results indicate that the MSED method outperforms the Stubbs index method for structural damage detection.

Wang, Shuqing; Liu, Fushun; Zhang, Min

2014-06-01

432

Cathodic protection retrofit of an offshore pipeline  

SciTech Connect

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

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

1997-09-01

433

Preliminary stratigraphic and paleomagnetic results from Neogene basins across the Anatolian Plateau (Turkey).  

NASA Astrophysics Data System (ADS)

An integrated paleomagnetic and stratigraphic study on Neogene basins across the Anatolian Plateau was carried out. This study is developed within the VAMP (Vertical Anatolian Movement Project), an interdisciplinary project aimed to the recent tectonic evolution of the central Anatolian Plateau. The studied areas are located in southern Turkey (Adana, Mut and Ermenek basins) and in northern Turkey (Kazan, Çankiri, Kastamonu, Boyabat and Sinop basins). For paleomagnetic analyses we sampled 1062 standard cylindrical samples from 13 stratigraphic sections, and 746 samples for paleontological analysis were taken from the same sections. AMS (Anisotropy of Magnetic Susceptibility), magnetic mineralogy and paleomagnetic polarity data are presented together with the results of the integrated stratigraphic analyses. In the Southern Turkey basins preliminary results show the diffuse presence of authigenic iron sulphides, together with magnetite, as main magnetic carriers. In these sections the iron-sulphides Characteristic Natural Magnetization (ChRM) component is characterized by inconsistent polarity record, suggesting that iron-sulphides have a late diagenetic origin. Conversely, magnetite bearing sediments show more reliable results in term of magnetic polarity interpretations. Preliminary stratigraphic and paleomagnetic results from the southern margin of the plateau allow us both to refine the stratigraphy for the late Miocene of the Adana Basin and to better constrain the age of the youngest marine deposits of the Mut and Ermenek basins. In the late Miocene of the Adana Basin evidence of the Messinian salinity crisis led to a new stratigraphic framework specially for the Messinian-Pliocene interval. Thick fluvial conglomerates from the uppermost Messinian deposits of the Adana Basin, which could be linked to the activation of the southern margin of the plateau, allow us to constrain at about 5.4 Ma the uplift of the central Anatolian Plateau. On the other hand, the preliminary results of the micropaleontological analyses carried out on the higher marine deposits sampled in the northern part of the Ermenek Basin (Basyayla section, 1840 m a.s.l.) point to a post-Tortonian age for the plateau uplift. The age of the basins at the northern margin of the plateau are very poor constrained, except for that basins containing vertebrate-bearing continental deposits. However, from a palaeogeographic point of view, our preliminary data suggest a possible Tortonian connection between the Çankiri Basin and the Paratethyan realm. This presentation was supported by the EUROCORE programme TOPO-EUROPE of the European Science Foundation.

Lucifora, Stella; Cifelli, Francesca; Mazzini, Ilaria; Cosentino, Domenico; Mattei, Massimo; Cipollari, Paola; Gliozzi, Elsa; Palolo Cavinato, Gian

2010-05-01

434

COMPARATIVE TOXICITY OF OFFSHORE AND OIL-ADDED DRILLING MUDS TO LARVAE OF THE GRASS SHRIMP 'PALAEMONETES INTERMEDIUS'  

EPA Science Inventory

Offshore drilling fluids (muds) varied widely in their toxicity to grass shrimp (Palaemonetes intermedius) larvae. The 96-hr LC50S for the eleven drilling muds tested ranged from 142 to >100,000 ppm (microliters/L). There was a significant correlation between oil content of the d...

435

Numerical modeling and Hardware-in-the-Loop simulation of undersea networks, ocean observatories and offshore communications backbones  

Microsoft Academic Search

This paper discusses the importance of taking a systems engineering approach when designing undersea networks, ocean observatories and offshore communications backbones. A design that utilizes modular components and systems, and places diligence in modeling and testing communications, power and data bandwidth requirements is essential for sustained operation and economic feasibility. An example is the modular seafloor communications network described -

Andrew M. Clark; Donna M. Kocak; Ken Martindale; Adrian Woodroffe

2009-01-01

436

Non-marine successions in the northwestern part of Kyongsang Basin (Early Cretaceous): Fluvial styles and stratigraphic architecture  

Microsoft Academic Search

Non-marine successions in the northwestern part of Kyongsang Basin (Early Cretaceous) are divided into successive stratigraphic\\u000a units based on facies assemblages and architecture of sandstone bodies. In the present study, two stratigraphic units (Sinpyong-Anpyong\\u000a and Jotap units) are documented in detail in terms of fluvial architecture. The Sinpyong-Anpyong unit is divided into thick\\u000a sandstone, thin sandstone, and mudstone-dominated bodies, representing

Hyung Rae Jo

2003-01-01

437

Core Description, Stratigraphic Correlation, and Mapping: A capstone project for an undergraduate course in Sedimentary Geology  

NSDL National Science Digital Library

This project is intended as a long-term (3 weeks1 month) lab exercise near the end of a combined Stratigraphy/Sedimentology course. The project utilizes real world data provided by CONSOL Energy of Pittsburgh, PA, and the West Virginia Geological and Economic Survey. This project has been assigned once and is being revised. Instructions have been left somewhat vague in an attempt to force students into discovering some of the more mechanical details of this process themselves. By the latter third of the course, students have described sedimentary rocks in detail and have constructed vertical sections of rock at several outcrops around campus. The course is moving from Sedimentology/Petrology into Stratigraphy. This project is designed to illustrate the basic principles of lithostratigraphy, which are covered concurrently in the lecture portion of the class. The project 'unfurls' over several weeks. If students are provided with the entire project at one time they generally get overwhelmed, so the project is presented piecemeal, allowing the students to expand the project as they complete one section. Step 1: Core description 40 feet of core from the Conemaugh Group of southwestern Pennsylvania is made available to the students. They must describe the core, define lithologic units, identify specific sedimentary structures, and construct a stratigraphic column. (Students struggle with detail versus efficiency of completion, given one full lab period (3 hours) and a week to complete the assignment, many students will get lost in the detail) The goal is to build familiarity with the type of data available to geologists as they go about constructing maps for resource estimates. Additionally, the lithologies present in this core will be similar to those described in the geologist and drilling logs necessary to complete the next step. Each step is evaluated independently in this step concern is primarily with identification of basic lithologies (coal, sandstone, shale, limestone). Step 2: construction of strip logs for 25 core holes in northern West Virginia. Students are provided with a location map, logs for 25 holes, and elevation data. They must construct strip logs suitable for correlation, deciding upon scale and detail of presentation. Students are provided with a CD including the location map and a .pdf for each drill record. The logs vary between the simplicity of driller data (60' of "blue" shale) and the detail of geologist descriptions, students must balance the detail and simplicity. Additionally, students were faced with "long" logs (i.e. greater than 500') and "short" logs (i.e. less than 100'). This turned out to be extremely difficult, some students got very lost, producing long detailed logs that left them without much time for the last two steps. Students are again provided with a week to construct the strip logs, including the lab time for the week. Strip logs are evaluated for detail, accuracy, and utility (in many cases too much detail can be as confusing as too little). Step 3: construction of stratigraphic cross sections. The first time this project was assigned, there was little guidance provided to students beyond "choosing logs that covered the largest stratigraphic interval." This exceeded the grasp of most students so additional guidance will be provided in the next iteration of this project. A generalized stratigraphic column illustrating the basic characteristics of the Monongahela and Conemaugh groups will be provided to assist students with recognition of the basic formations. Students will be required to construct a stratigraphic cross section through selected wells on the west side of the project area. This cross section will demonstrate the use of marker beds and the lateral continuity of stratigraphic units. The second cross section will run east-west onto the western flank of the Chestnut Ridge anticline. The datum for this cross section will be surface elevation. This cross section will illustrate the problems of stratigraphic correlation when combined with geological structures. The rock becomes consistently older as one proceeds towards the axis of the anticline. The prominent red beds and the absence of coals, in the eastern portion of the map area indicate the presence of the Chestnut Ridge Anticline. Evaluation of the cross sections will be based upon the accuracy of the correlations. Students are allowed a week to produce cross sections (including lab). The stratigraphic cross section should accurately delineate the Redstone, Pittsburgh, and Sewickley coals. These occur in sequence and are fairly easy to identify. Successful completion of the east-west cross section will require identification of the approximate stratigraphic position of the Monongahela-Conemaugh contact. Step 4: construction of isopach maps. Students are then required to identify specific coal and sandstone units within their cross sections, correlate those across the map region and construct isopach maps of those units. This requires that the students now extend what they have learned from the previous three weeks, extend those correlations to the core holes not included in the basic stratigraphic analysis. The thickness of the coal and sandstone should be identified and isopach maps constructed. The first iteration of this project produced problems similar to those encountered in step 3. Better guidance and evaluation of the cross sections and allowing students less input on the choice of stratigraphic units to isopach should reduce the confusion. Step 5: (optional) Interpretation and report writing : the first iteration of this project was running concurrently with a term paper. Instead of two separate projects, an interpretive report will be required. This is still in the planning stage and has not been assigned to students.

Matchen, David L.

438

Proceedings of the nineteenth annual offshore technology conference. Vol. 3  

SciTech Connect

This book presents the papers given at a conference on offshore platforms. Topics considered at the conference included grouted pile-sleeve connections, tanker ships, mooring systems, offshore drilling, drill pipes, subsea control valves, thermal insulation coatings, submarine pipeline stability, computerized simulation, hydrodynamics, pipe-soil interactions, wellhead performance, marine risers, directional drilling, vibration monitoring, welding, economics, tension leg platforms, and storage facilities.

Not Available

1987-01-01

439

Advances in offshore oil and gas pipeline technology  

SciTech Connect

This book examines the problems involved in the offshore transport of petroleum and natural gas. Topics considered include geotechnical considerations, pipeline lay-stress analysis, pipeline reeling, buckling, pipeline trenching by ploughing, the automated connection of offshore pipelines, concrete coatings, cathodic protection, spanning problems, inspection, emergency repair, safety, reliability, pressure effects, marine risers, and single point mooring systems.

delaMare, R.F.

1985-01-01

440

OPTIMAL DEVELOPMENT PLANNING OF OFFSHORE OIL AND GAS FIELD  

E-print Network

OPTIMAL DEVELOPMENT PLANNING OF OFFSHORE OIL AND GAS FIELD INFRASTRUCTURE UNDER COMPLEX FISCAL Pittsburgh, PA 15213 Abstract The optimal development planning of offshore oil and gas fields has received, well drilling schedule and production profiles of oil, water and gas in each time period. The model can

Grossmann, Ignacio E.