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Craig J. Wandrey - One of the best experts on this subject based on the ideXlab platform.
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Sylhet-Kopili/Barail-Tipam Composite Total Petroleum System, Assam Geologic Province, India
2004Co-Authors: Craig J. WandreyAbstract:The Sylhet-Kopili/Barail-Tipam Composite Total Petroleum system (TPS) (803401) is located in the Assam Province in northeasternmost India and includes the Assam Shelf south of the Brahmaputra River. The area is primarily a southeastdipping shelf overthrust by the Naga Hills on the southeast and the Himalaya Mountain range to the north. The rocks that compose this TPS are those of the Sylhet-Kopili/Barail-Tipam composite petroleum system. These rocks are those of the Eocene-Oligocene Jaintia Group Sylhet and Kopili Formations, the Oligocene Barail Group, and the Oligocene-Miocene Surma and Tipam Groups. These groups include platform carbonates, shallow marine shales and sandstones, and the sandstones, siltstones, shales, and coals of deltaic and lagoonal facies. Source rocks include the Sylhet and Kopili Formation shales, Barail Group coals and shales, and in the south the Surma Group shales. Total organic carbon content is generally low, averaging from 0.5 to 1.8 percent; it is as high as 9 percent in the Barail Coal Shales. Maturities are generally low, from Ro (vitrinite reflectance) 0.45 to 0.7 percent where sampled. Maturity increases to the southeast near the Naga thrust fault and can be expected to be higher in the subthrust. Generation began in early Pliocene. Migration is primarily updip to the northwest (< 5 to 15 kilometers) along the northeast-trending slope of the Assam Shelf, and vertical migration occurs through reactivated basement-rooted faults associated with the plate collisions. Reservoir rocks are carbonates of the Sylhet Formation, interbedded sandstones of the Kopili Formation and sandstones of the Barail, Surma, and Tipam Groups. Permeability ranges from less than 8 mD (millidarcies) to as high as 800 mD in the Tipam Group. Porosity ranges from less than 7 percent to 30 percent. Traps are primarily anticlines and faulted anticlines with a few subtle stratigraphic traps. There is also a likelihood of anticlinal traps in the subthrust. Seals include interbedded Oligocene and Miocene shales and clays, and the thick clays of the Pliocene Gurjan Group. Introduction Among the 76 priority Provinces identified by the U.S. Geological Survey World Energy Assessment Team (2000) was the Assam Geologic Province. Located in northeastern India, Assam Geologic Province is an onshore Province covering approximately 74,000 km2 (figs. 1 and 2). The Geologic Province is bounded on the north and west by the Brahmaputra River, and on the south and east by the Indo-Burman Ranges and the Central Burma Basin (fig. 3). Major features within the Assam Geologic Province include the Assam Shelf, Brahmaputra River valley, Shillong Plateau, Mirkir Hills, and a foreland portion of the Indian Shield. The Assam Shelf consists of a portion of the Paleocene to Eocene continental shelf of the Indian plate which became emergent and which is being overthrust by the Himalayas on the northwest and by the Burma micro-plate on the southeast. Structurally, the Assam Geologic Province consists of two primary, subparallel features trending southwest to northeast, which developed just prior to, and as a result of plate collision. The northernmost structural feature is the Assam Shelf, which is presently being subducted beneath both the Eurasian plate to the north and the Burma plate to the southeast. The southernmost feature consists of en-echelon folds of the Naga Hills overthrust belt and northernmost Indo-Burman Ranges, which are continually developing as the shelf is subducted. At present, most hydrocarbon production is northwest of, and parallel to, the Naga thrust fault. Figure 2 shows Brahmaputra River flowing from east (right) to west (left) and tributaries flowing from the Himalayan ranges at the top of the view (north) and from the Naga Hills in the bottom of the view (south). The producing area lies south of the Brahmaputra River. Acknowledgments Insight into the geology and data presented in this report were provided by scientists of the Oil and Natural Gas Corporation (ONGC), Dehra Dun, India. Sylhet-Kopili/Barail-Tipam Composite Total Petroleum System, Assam Geologic Province, India
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sylhet kopili barail tipam composite total petroleum system assam Geologic Province india
Bulletin, 2004Co-Authors: Craig J. WandreyAbstract:The Sylhet-Kopili/Barail-Tipam Composite Total Petroleum system (TPS) (803401) is located in the Assam Province in northeasternmost India and includes the Assam Shelf south of the Brahmaputra River. The area is primarily a southeastdipping shelf overthrust by the Naga Hills on the southeast and the Himalaya Mountain range to the north. The rocks that compose this TPS are those of the Sylhet-Kopili/Barail-Tipam composite petroleum system. These rocks are those of the Eocene-Oligocene Jaintia Group Sylhet and Kopili Formations, the Oligocene Barail Group, and the Oligocene-Miocene Surma and Tipam Groups. These groups include platform carbonates, shallow marine shales and sandstones, and the sandstones, siltstones, shales, and coals of deltaic and lagoonal facies. Source rocks include the Sylhet and Kopili Formation shales, Barail Group coals and shales, and in the south the Surma Group shales. Total organic carbon content is generally low, averaging from 0.5 to 1.8 percent; it is as high as 9 percent in the Barail Coal Shales. Maturities are generally low, from Ro (vitrinite reflectance) 0.45 to 0.7 percent where sampled. Maturity increases to the southeast near the Naga thrust fault and can be expected to be higher in the subthrust. Generation began in early Pliocene. Migration is primarily updip to the northwest (< 5 to 15 kilometers) along the northeast-trending slope of the Assam Shelf, and vertical migration occurs through reactivated basement-rooted faults associated with the plate collisions. Reservoir rocks are carbonates of the Sylhet Formation, interbedded sandstones of the Kopili Formation and sandstones of the Barail, Surma, and Tipam Groups. Permeability ranges from less than 8 mD (millidarcies) to as high as 800 mD in the Tipam Group. Porosity ranges from less than 7 percent to 30 percent. Traps are primarily anticlines and faulted anticlines with a few subtle stratigraphic traps. There is also a likelihood of anticlinal traps in the subthrust. Seals include interbedded Oligocene and Miocene shales and clays, and the thick clays of the Pliocene Gurjan Group. Introduction Among the 76 priority Provinces identified by the U.S. Geological Survey World Energy Assessment Team (2000) was the Assam Geologic Province. Located in northeastern India, Assam Geologic Province is an onshore Province covering approximately 74,000 km2 (figs. 1 and 2). The Geologic Province is bounded on the north and west by the Brahmaputra River, and on the south and east by the Indo-Burman Ranges and the Central Burma Basin (fig. 3). Major features within the Assam Geologic Province include the Assam Shelf, Brahmaputra River valley, Shillong Plateau, Mirkir Hills, and a foreland portion of the Indian Shield. The Assam Shelf consists of a portion of the Paleocene to Eocene continental shelf of the Indian plate which became emergent and which is being overthrust by the Himalayas on the northwest and by the Burma micro-plate on the southeast. Structurally, the Assam Geologic Province consists of two primary, subparallel features trending southwest to northeast, which developed just prior to, and as a result of plate collision. The northernmost structural feature is the Assam Shelf, which is presently being subducted beneath both the Eurasian plate to the north and the Burma plate to the southeast. The southernmost feature consists of en-echelon folds of the Naga Hills overthrust belt and northernmost Indo-Burman Ranges, which are continually developing as the shelf is subducted. At present, most hydrocarbon production is northwest of, and parallel to, the Naga thrust fault. Figure 2 shows Brahmaputra River flowing from east (right) to west (left) and tributaries flowing from the Himalayan ranges at the top of the view (north) and from the Naga Hills in the bottom of the view (south). The producing area lies south of the Brahmaputra River. Acknowledgments Insight into the geology and data presented in this report were provided by scientists of the Oil and Natural Gas Corporation (ONGC), Dehra Dun, India. Sylhet-Kopili/Barail-Tipam Composite Total Petroleum System, Assam Geologic Province, India
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Patala-Nammal Composite Total Petroleum System, Kohat-Potwar Geologic Province, Pakistan
2004Co-Authors: Craig J. Wandrey, B.e. Law, Haider Ali ShahAbstract:This report describing the petroleum resources within a total petroleum system in Pakistan was prepared as part of the World Energy Assessment Project of the U.S. Geological Survey. For this project, the world was divided into 8 regions and 937 Geologic Provinces, which were then ranked according to the discovered oil and gas volumes within each (Klett and others, 1997). Of these, 76 ‘‘priority’’ Provinces (exclusive of the United States and chosen for their high ranking) and 26 ‘‘boutique’’ Provinces (exclusive of the United States and chosen for their anticipated petroleum richness or special regional economic importance) were selected for appraisal of oil and gas resources. The petroleum geology of these priority and boutique Provinces is described in this series of reports. The purpose of the World Energy Project is to assess the quantities of oil, gas, and natural gas liquids that have the potential to be added to reserves within the next 30 years. These volumes either reside in undiscovered fields whose sizes exceed the stated minimum-field-size cutoff value for the assessment unit (variable, but must be at least 1 million barrels of oil equivalent) or occur as reserve growth of fields already discovered. The total petroleum system constitutes the basic Geologic unit of the oil and gas assessment. The total petroleum system includes all genetically related petroleum that occurs in shows and accumulations (discovered and undiscovered) and that (1) has been generated by a pod or by closely related pods of mature source rock, and (2) exists within a limited, mappable Geologic space, along with the other essential, mappable Geologic elements (reservoir, seal, and overburden) that control the fundamental processes of generation, expulsion, migration, entrapment, and preservation of petroleum. The minimum petroleum system is that part of a total petroleum system encompassing discovered shows and accumulations along with the Geologic space in which the various essential elements have been proved by these discoveries. An assessment unit is a mappable part of a total petroleum system in which discovered and undiscovered fields constitute a single, relatively homogenous population such that the chosen methodology of resource assessment based on estimation of the number and sizes of undiscovered fields is applicable. A total petroleum system may equate to a single assessment unit, or it may be subdivided into two or more assessment units if each unit is sufficiently homogeneous in terms of geology, exploration considerations, and risk to assess individually. A graphical depiction of the elements of a total petroleum system is provided in the
William C. Burton - One of the best experts on this subject based on the ideXlab platform.
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Characteristics of Water-Well Yields in Part of the Blue Ridge Geologic Province in Loudoun County, Virginia
Natural Resources Research, 2001Co-Authors: David M. Sutphin, Lawrence J. Drew, John H. Schuenemeyer, William C. BurtonAbstract:Loudoun County, Virginia, which is located about 50 km to the west of Washington, DC, was the site of intensive suburban development during the 1980s and 1990s. In the western half of the county, the source of water for domestic use has been from wells drilled into the fractured crystalline bedrock of the Blue Ridge Geologic Province. A comprehensive digital database that contains information on initial yield, location, depth, elevation, and other data for 3651 wells drilled in this 825.5-km^2 area was combined with a digital Geologic map to form the basis for a study of Geologic and temporal controls on water-well yields. Statistical modeling procedures were used to determine that mean yields for the wells were significantly different as a function of structural setting, genetic rock type, and Geologic map unit. The Bonferroni procedure then was used to determine which paired comparisons contributed to these significant differences. The data were divided into 15 temporal drilling increments to determine if the time-dependent trends that exist for the Loudoun County data are similar to those discovered in a previous study of water-well yields in the Pinardville 7.5-min quadrangle, New Hampshire. In both regions, trends, which include increasing proportions of very low yield wells and increasing well depths through time, and the counterintuitive result of increasing mean well yields through time, were similar. In addition, a yield-to-depth curve similar tothat discovered in the Pinardville quadrangle was recognized in this study. Thus, the temporal model with a feed-forward-loop mechanism to explain the temporal trends in well characteristics proposed for the New Hampshire study appears to apply to western Loudoun County.
Co Timothy R. Klett - One of the best experts on this subject based on the ideXlab platform.
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au_sum (Summary Assessment Data of World Assessment Units)
2000Co-Authors: Feliks M. Persits, Contractor To Usgs, Denver, Co Douglas W. Steinshouer, Co Timothy R. KlettAbstract:This coverage includes arcs, polygons, polygon labels and regions that describe U.S. Geological Survey defined petroleum resource Assessment Units of the World. Each assessment unit is defined as a mappable volume of rock within a total petroleum system that encompasses fields (discovered and undiscovered) that share similar Geologic traits and socio-economic factors. The fields inside an assessment are a sufficiently homogenous population that a single methodology of resource assessment is applicable. Assessment units are described by U.S. Geological Survey research scientists on the basis of available Geologic knowledge, exploration and production histories, and extensive literature searches. Assessment units are identified with a numeric code derived from the numeric code of the World Geologic Provinces defined by the U.S. Geological Survey World Petroleum Assessment 2000. Most assessment units are contained within a single Geologic Province, but there are numerous cases where units span more than one Province. Summary results of the assessment are presented as attributes of this coverage.
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tps_sum World Total Petroleum System Summary Result Data
2000Co-Authors: Feliks M. Persits, Contractor To Usgs, Denver, Co Douglas W. Steinshouer, Co Timothy R. KlettAbstract:This coverage includes arcs, polygons, polygon labels and regions that describe U.S. Geological Survey delineated Total Petroleum Systems of the World. Each petroleum system is defined as a mappable entity encompassing genetically related petroleum that occurs in seeps, shows and accumulations (discovered or undiscovered) that have been generated by a pod, or by closely related pods, of mature source rock, together with the essental mappable Geologic elements (source, reservoir, seal and overburden rocks) that control fundamental processes of generation, migration, entrapment and preservation of petroleum. Total petroleum systems are described by U.S. Geological Survey scientists on the basis of exploration and production histories, and extensive literature searches. Total petroleum systems are identified with a numeric code derived from the numeric code of the World Geologic Provinces as defined by the U.S. Geological Survey World Energy Project. Most total petroleum systems are contained within a single Geologic Province, but there are numerous cases where systems span more than one Province. Summary results are presented as attributes of this coverage.
Joseph D. Ayotte - One of the best experts on this subject based on the ideXlab platform.
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The influence of geology and land use on arsenic in stream sediments and ground waters in New England, USA
Applied Geochemistry, 2006Co-Authors: Gilpin R. Robinson, Joseph D. AyotteAbstract:Population statistics for As concentrations in rocks, sediments and ground water differ by geology and land use features in the New England region, USA. Significant sources of As in the surficial environment include both natural weathering of rocks and anthropogenic sources such as arsenical pesticides that were commonly applied to apple, blueberry and potato crops during the first half of the 20th century in the region. The variation of As in bedrock ground water wells has a strong positive correlation with Geologic features at the Geologic Province, lithology group, and bedrock map unit levels. The variation of As in bedrock ground water wells also has a positive correlation with elevated stream sediment and rock As chemistry. Elevated As concentrations in bedrock wells do not correlate with past agricultural areas that used arsenical pesticides on crops. Stream sediments, which integrate both natural and anthropogenic sources, have a strong positive correlation of As concentrations with rock chemistry, Geologic Provinces and ground water chemistry, and a weaker positive correlation with past agricultural land use. Although correlation is not sufficient to demonstrate cause-and-effect, the statistics favor rock-based As as the dominant regional source of the element in stream sediments and ground water in New England. The distribution of bedrock geology features at the Geologic Province, lithology group and map unit level closely correlate with areas of elevated As in ground water, stream sediments, and rocks.
David M. Sutphin - One of the best experts on this subject based on the ideXlab platform.
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Characteristics of Water-Well Yields in Part of the Blue Ridge Geologic Province in Loudoun County, Virginia
Natural Resources Research, 2001Co-Authors: David M. Sutphin, Lawrence J. Drew, John H. Schuenemeyer, William C. BurtonAbstract:Loudoun County, Virginia, which is located about 50 km to the west of Washington, DC, was the site of intensive suburban development during the 1980s and 1990s. In the western half of the county, the source of water for domestic use has been from wells drilled into the fractured crystalline bedrock of the Blue Ridge Geologic Province. A comprehensive digital database that contains information on initial yield, location, depth, elevation, and other data for 3651 wells drilled in this 825.5-km^2 area was combined with a digital Geologic map to form the basis for a study of Geologic and temporal controls on water-well yields. Statistical modeling procedures were used to determine that mean yields for the wells were significantly different as a function of structural setting, genetic rock type, and Geologic map unit. The Bonferroni procedure then was used to determine which paired comparisons contributed to these significant differences. The data were divided into 15 temporal drilling increments to determine if the time-dependent trends that exist for the Loudoun County data are similar to those discovered in a previous study of water-well yields in the Pinardville 7.5-min quadrangle, New Hampshire. In both regions, trends, which include increasing proportions of very low yield wells and increasing well depths through time, and the counterintuitive result of increasing mean well yields through time, were similar. In addition, a yield-to-depth curve similar tothat discovered in the Pinardville quadrangle was recognized in this study. Thus, the temporal model with a feed-forward-loop mechanism to explain the temporal trends in well characteristics proposed for the New Hampshire study appears to apply to western Loudoun County.