Plio-Pleistocene Depositional Sequences of the Southwestern Louisiana Continental Shelf and Slope: Geologic Framework, Sedimentary Facies and Hydrocarbon Distribution

The Plio-Pleistocene hydrocarbon fairway of offshore Louisiana is restricted to the outer continental shelf and upper continental slope where a thick wedge of nearshore and deep marine sediments was deposited. Electric logs, paleontological reports, and seismic profiles form the basis for (1) dividing the wedge of Plio-Pleistocene strata into eight genetic sequences, (2) establishing the structural framework, (3) determining the timing of deformation, and (4) mapping the principal depositional systems of the West Cameron and western Garden Banks areas during the past five million years. Sedimentary facies and structural styles in this part of the basin are highly variable owing to contemporaneous sea-level fluctuations, salt migration, and shifting sites of deltaic, shelf, and slope sedimentation. The resulting complex geologic history of this part of the basin directly controlled the generation, migration, and entrapment of hydrocarbons. The early Pliocene was a period of continental platform inundation and deposition of a thick succession of marine mudstones. About 3 Ma, this monotonous accumulation of deep-water mudstone was interrupted by deposition of sand-rich submarine channels and fans associated with a lowering of sea level. These lowstand deposits extended at least 55 mi (90 km) basinward of the paleomargin. Overlying Pleistocene sediments were deposited mainly by prograding mud-rich fluvial-deltaic systems of moderate size. These rivers and shelf-edge deltas constructed a broad continental platform that buried the submarine fans and prograded the shelf margin approximately 70 mi (110 km) basinward. During this rapid outbuilding, slumping and other gravity-driven mass transport processes removed sand-rich delta-front sediments from unstable shelf margins and redeposited them on the continental slope.Bureau of Economic Geolog

Plio-Pleistocene Depositional Sequences of the Southwestern Louisiana Continental Shelf and Slope: Geologic Framework, Sedimentary Facies and Hydrocarbon Distribution

The Plio-Pleistocene hydrocarbon fairway of offshore Louisiana is restricted to the outer continental shelf and upper continental slope where a thick wedge of nearshore and deep marine sediments was deposited. Electric logs, paleontological reports, and seismic profiles form the basis for (1) dividing the wedge of Plio-Pleistocene strata into eight genetic sequences, (2) establishing the structural framework, (3) determining the timing of deformation, and (4) mapping the principal depositional systems of the West Cameron and western Garden Banks areas during the past five million years. Sedimentary facies and structural styles in this part of the Gulf Coast basin are highly variable owing to contemporaneous sea-level fluctuations, salt migration, and shifting sites of deltaic, shelf, and slope sedimentation. The resulting complex geologic history of this part of the basin was interpreted to determine what controlled the generation, migration, and entrapment of hydrocarbons. The early Pliocene was a period of continental platform inundation and deposition of a thick succession of marine mudstones. About 3 million years ago, this monotonous accumulation of deep-water mudstone was interrupted by deposition of sand-rich submarine channels and fans associated with a lowering of sea level. These lowstand deposits extended at least 55 miles (90 km) basinward of the paleomargin. Overlying Pleistocene sediments were deposited mainly by prograding mud-rich fluvial-deltaic systems of moderate size. These rivers and shelf-edge deltas constructed a broad continental platform that buried the submarine fans and prograded the shelf margin approximately 70 miles (110 km) basinward. During this rapid outbuilding, slumping and other gravity-driven mass transport processes removed sand-rich delta-front sediments from unstable shelf margins and redeposited them on the continental slope.Bureau of Economic Geolog

Coordination of Geological and Engineering Research in Support of Gulf Coast Co-Production Program

More than 150 gas fields were reviewed, and 25 fields were selected using modified specific selection criteria as outlined by Gregory and others (1983). Further evaluation of these fields is necessary to obtain a new ranking for Gregory's class A, B, and C divisions. A list of the 25 most favorable fields was sent to Eaton Operating Co., who were to approach likely companies to initiate joint ventures in co-production. Four reservoirs containing dispersed gas were examined for their co-production potential. Reservoirs in Port Acres and Ellis fields produce from the Hackberry Member of the Oligocene Frio Formation, and two reservoirs in Esther field produce from the lower Miocene Planulina Zone. Log-pattern and lithofacies maps, together with stratigraphic position, suggest that the reservoirs are in ancient submarine-fan deposits. Dip-elongate, channel-fill sands are characteristic; reservoir sands pinch out along strike. Growth faults, common in the submarine slope setting, form updip and downdip boundaries, producing combination traps. In Ellis field, co-production accounts for 300 Mcf (8.5 x 106 m3) of gas per day. Port Acres field contains the largest remaining reserves, but other technical and economic factors limit co-production there. Recent drilling has extended primary production and delayed co-production in Esther field. The Gas Research Institute requested that further work on the selection and evaluation of potential co-production gas fields be terminated because funds were required for the Port Arthur project.Bureau of Economic Geolog

Geologic Evaluation of Critical Production Parameters for Coalbed Methane Resources: Part 1, San Juan Basin

The Fruitland Formation in the San Juan Basin is the major producer of coalbed methane in the Western U.S. Forty-three to forty-nine Tcf of methane occur in 245 billion short tons of Fruitland coal at depths between 400 and 4,200 ft. Thickest Fruitland coal seams trend northwest and occur in the northern part of the basin, northeast of a syndepositional, structural hinge line; they occur in coastal plain facies southwest of Pictured Cliffs barrier/strandplain sandstones. South of the hinge line, northeast-trending coal seams occur in floodplain facies between northeast-trending Fruitland fluvial systems. Face cleat trends in Fruitland coal seams are predominantly northeast in the southern two-thirds of the basin and northwest but variable in the northern third. Suggested targets for enhanced coalbed permeability are tectonic fractures and fractures associated with subtle folds. Fruitland Formation waters are evolved meteoric waters; water composition reflects hydrologic setting. Waters in the north-central San Juan Basin have high alkalinity and low chlorinity; waters in the southern part are Na-Cl type. Distribution of low-chloride ground water in the Fruitland Formation in the north-central basin coincides with the overpressured area and with flow patterns inferred from the head map. The Fruitland Formation acts regionally as a single hydrologic unit or homogeneous aquifer, but large pressure gradients locally indicate that Fruitland strata may be hydraulically disconnected and behave at the field scale as compartmentalized aquifers. Hydrologic studies defined reservoir characteristics and permeability boundaries in the Fruitland Formation. Geologic and hydrologic parameters were used to divide the San Juan Basin into areas in which coal beds have similar reservoir characteristics. Coalbed wells have negative declines early in their production history followed by exponential decline rates at less than 5 percent/year. Sandstone wells that exhibit coal-decline behavior probably are producing coalbed methane indirectly from coal seams.Bureau of Economic Geolog

An Assessment of the Natural Gas Resource Base of the United States

The distribution of natural gas in the United States comprises proved reserves in known reservoirs, inferred reserves, undeveloped resources within these reservoirs, and undiscovered resources. Beyond proved reserves, all volumes of future natural gas supply are estimates based on information derived from past and current experience in gas production and reservoir development. Even proved reserves are subject to periodic revision. This assessment begins with an understanding of major components of the natural gas supply derived from existing resource estimates that use established methodologies. In addition to historically defined elements of the resource base, a new component—reserve growth in heterogeneous reservoirs—is quantified in this study. Resource assessments proceed in their planning and compilation from reasonably well-known quantities (proved reserves) to increasingly less well-known quantities (undiscovered resources). Furthermore, natural gas reservoirs termed unconventional are typically given separate consideration and include gas in low-permeability reservoirs, gas in shale formations such as the Devonian of the Eastern U.S., and coalbed methane resources. This approach has been followed in this assessment. Special note was made of Alaskan gas reserves as they are significant and proven, but transportation for North Slope gas to the Lower 48 states is lacking.Bureau of Economic Geolog

Evaluation of 2004 Toyota Prius Hybrid Electic Drive System Interim Report - Revised

The 2004 Toyota Prius is a hybrid automobile equipped with a gasoline engine and a battery-powered electric motor. Both of these motive power sources are capable of providing mechanical drive power for the vehicle. The engine can deliver a peak power output of 57 kilowatts (kW) at 5000 revolutions per minute (rpm) while the motor can deliver a peak power output of 50 kW at 1300 rpm. Together, this engine-motor combination has a specified peak power output of 82 kW at a vehicle speed of 85 kilometers per hour (km/h). In operation, the 2004 Prius exhibits superior fuel economy compared to conventionally powered automobiles. Laboratory tests were conducted to evaluate the electrical and mechanical performance of the 2004 Toyota Prius and its hybrid electric drive system. As a hybrid vehicle, the 2004 Prius uses both a gasoline-powered internal combustion engine and a battery-powered electric motor as motive power sources. Innovative algorithms for combining these two power sources results in improved fuel efficiency and reduced emissions compared to traditional automobiles. Initial objectives of the laboratory tests were to measure motor and generator back-electromotive force (emf) voltages and determine gearbox-related power losses over a specified range of shaft speeds and lubricating oil temperatures. Follow-on work will involve additional performance testing of the motor, generator, and inverter. Information contained in this interim report summarizes the test results obtained to date, describes preliminary conclusions and findings, and identifies additional areas for further study

Classical kinetic energy, quantum fluctuation terms and kinetic-energy functionals

We employ a recently formulated dequantization procedure to obtain an exact expression for the kinetic energy which is applicable to all kinetic-energy functionals. We express the kinetic energy of an N-electron system as the sum of an N-electron classical kinetic energy and an N-electron purely quantum kinetic energy arising from the quantum fluctuations that turn the classical momentum into the quantum momentum. This leads to an interesting analogy with Nelson's stochastic approach to quantum mechanics, which we use to conceptually clarify the physical nature of part of the kinetic-energy functional in terms of statistical fluctuations and in direct correspondence with Fisher Information Theory. We show that the N-electron purely quantum kinetic energy can be written as the sum of the (one-electron) Weizsacker term and an (N-1)-electron kinetic correlation term. We further show that the Weizsacker term results from local fluctuations while the kinetic correlation term results from the nonlocal fluctuations. For one-electron orbitals (where kinetic correlation is neglected) we obtain an exact (albeit impractical) expression for the noninteracting kinetic energy as the sum of the classical kinetic energy and the Weizsacker term. The classical kinetic energy is seen to be explicitly dependent on the electron phase and this has implications for the development of accurate orbital-free kinetic-energy functionals. Also, there is a direct connection between the classical kinetic energy and the angular momentum and, across a row of the periodic table, the classical kinetic energy component of the noninteracting kinetic energy generally increases as Z increases.Comment: 10 pages, 1 figure. To appear in Theor Chem Ac

Protecting eyewitness evidence: Examining the efficacy of a self-administered interview tool

Given the crucial role of eyewitness evidence, statements should be obtained as soon as possible after an incident. This is not always achieved due to demands on police resources. Two studies trace the development of a new tool, the Self-Administered Interview (SAI), designed to elicit a comprehensive initial statement. In Study 1, SAI participants reported more correct details than participants who provided a free recall account, and performed at the same level as participants given a Cognitive Interview. In Study 2, participants viewed a simulated crime and half recorded their statement using the SAI. After a delay of 1 week, all participants completed a free recall test. SAI participants recalled more correct details in the delayed recall task than control participants

Modern optical astronomy: technology and impact of interferometry

The present `state of the art' and the path to future progress in high spatial resolution imaging interferometry is reviewed. The review begins with a treatment of the fundamentals of stellar optical interferometry, the origin, properties, optical effects of turbulence in the Earth's atmosphere, the passive methods that are applied on a single telescope to overcome atmospheric image degradation such as speckle interferometry, and various other techniques. These topics include differential speckle interferometry, speckle spectroscopy and polarimetry, phase diversity, wavefront shearing interferometry, phase-closure methods, dark speckle imaging, as well as the limitations imposed by the detectors on the performance of speckle imaging. A brief account is given of the technological innovation of adaptive-optics (AO) to compensate such atmospheric effects on the image in real time. A major advancement involves the transition from single-aperture to the dilute-aperture interferometry using multiple telescopes. Therefore, the review deals with recent developments involving ground-based, and space-based optical arrays. Emphasis is placed on the problems specific to delay-lines, beam recombination, polarization, dispersion, fringe-tracking, bootstrapping, coherencing and cophasing, and recovery of the visibility functions. The role of AO in enhancing visibilities is also discussed. The applications of interferometry, such as imaging, astrometry, and nulling are described. The mathematical intricacies of the various `post-detection' image-processing techniques are examined critically. The review concludes with a discussion of the astrophysical importance and the perspectives of interferometry.Comment: 65 pages LaTeX file including 23 figures. Reviews of Modern Physics, 2002, to appear in April issu