31 research outputs found
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Stratigraphy and petroleum potential of pre-Pennsylvanian rocks : Palo Duro Basin, Texas Panhandle
UT Librarie
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Mississippian Depositional History of the Texas Panhandle: A Reappraisal
Recent lithostratigraphic and biostratigraphic studies of subsurface Mississippian rocks in the Texas Panhandle suggest that previous interpretations of the sequence and timing of depositional events in the area require revision.
During the Early Mississippian period (Kinderhookian to Osagean), deposition in the area was limited to the northeastern Panhandle (Anadarko Basin), while the Texas Arch, a Devonian structure, remained positive, preventing sediment accumulation in the rest of the area. It wasn't until the Meramecian stage that a significant inundation occurred in the southern Panhandle. Shallow platform conditions developed in the submerged area around the Texas Arch, with carbonate buildups forming locally on the outer ramp along the previous margin of the Arch. This marine transgression corresponds to the drowning of platform margins across the midcontinent region. The Texas Arch intermittently controlled deposition until the end of the Mississippian Period.Bureau of Economic Geolog
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Report of Investigations No. 123 Petroleum Potential of the Palo Duro Basin, Texas Panhandle
UT Librarie
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Potential for Petroleum Resources in the Palo Duro Basin Area, Texas Panhandle
Investigations of the petroleum potential of the Palo Duro Basin have been underway since 1978. This report contains the results of studies carried out during the 1983-84 fiscal year, which have not yet been published.
The section of this report dealing with pre-Pennsylvanian units in the basin represents the final results of work done on these rocks. Work is continuing on Pennsylvanian and younger strata as further data become available.
The second part of this report presents additional data recently gathered on these units.Bureau of Economic Geolog
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Effects of Stratal Architecture and Diagenesis on Reservoir Development in the Grayburg Formation: South Cowden Field, Ector County, Texas
The Grayburg Formation in the South Cowden field of eastern Ector County displays an internal stratal architecture that typifies Grayburg shallow-water platform successions throughout the Permian Basin. Study of core and wireline logs in South Cowden field documents three orders of cyclicity in the Grayburg. The entire Grayburg constitutes a single long-duration accommodation cycle that commenced with a major sea-level rise and flooding of the preexisting San Andres platform and ended with a major basinward shift in facies associated with sea-level fall prior to deposition of Queen Formation tidal-flat successions. Four high-frequency sequences are recognized within the Grayburg that correspond to higher frequency sea-level rise events. The basal Grayburg sequence consists of backstepping, low-energy, mud-dominated cycles and is not a contributor to production in the field. Grayburg sequence 2 documents extensive flooding of the San Andres platform by outer ramp fusulinid wackestone-packstone facies and subsequent aggradation of an extensive tidal-flat-capped, grain-dominated packstone-grainstone ramp crest succession. Renewed platform transgression in Grayburg sequence 3, demonstrated by even more extensive onlap of the platform by fusulinid facies, documents a maximum flooding event that is correlatable throughout the Grayburg in both outcrop and subsurface. This event forms the basis for correlation of the Grayburg succession throughout the Permian Basin. Grayburg sequence 4 reflects highstand reduction of platform-to-basin relief and a major basinward shift in facies tracts.Bureau of Economic Geolog
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Multidisciplinary Imaging of Rock Properties in Carbonate Reservoirs for Flow-Unit Targeting
Excellent progress has been made on all project objectives and goals. All tasks have been completed in the Phase 1 study area, the initial area of project focus. Primary elements of this work include the following: The stratigraphic architecture has been established through correlation of wireline logs guided by core and outcrop studies of facies and cyclicity. A porosity model has been developed that creates a basis for calculation of porosity for wells in the study area. Rock fabrics have been defined by sampling, analysis, and description of cores and used to create transforms for calculating permeability and oil saturation from porosity data. Finally, a preliminary 3-D model has been constructed that incorporates stratigraphic architecture, rock-fabric data, and petrophysical data. Reservoir volumetrics calculated from the model show that a very large fraction of the original oil in place remains
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Stratigraphic Studies of the Palo Duro Basin: An Update
Stratigraphic studies of the Palo Duro Basin are now in their 8th year. Although the emphasis in these studies now lies in the San Andres Formation (possible repository host rock) and the Wolfcamp Series (sub-repository aquifer), investigations of other units (fig. 1) continue to be carried out as well. This report includes work that was not available for inclusion in last year's (1983) CSR on stratigraphy (Open File Report No. OF-WTWI-1984-30). The section on pre-Pennsylvanian stratigraphy represents the final stages of study of those units. The report detailing structural controls on deposition of the San Andres is part of an ongoing effort to recognize indications of structural or tectonic controls on sedimentation throughout the stratigraphic column in the Palo Duro Basin area. Studies of the Dockum Group are revealing similar controls during the Triassic. Core studies of the Dockum are increasing our resolution of depositional settings in the area.Bureau of Economic Geolog
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Stratigraphy of the Palo Duro Basin- A Status Report
Since the beginning of Bureau research into the Palo Duro Basin area in 1979, more than 150 geologic reports have been completed and published. Approximately 30 are currently in press. Because of continuing research in the area, however, a great deal of additional work still remains unpublished. This report provides an update on ongoing, as yet unpublished research into the stratigraphy of the Palo Duro Basin (fig. 1).
Although investigations on some scale are being carried out on essentially all of the stratigraphic horizons in the Palo Duro Basin area (fig. 2), only those units which have recently been the focus of relatively concentrated research efforts are reported herein. This necessarily includes those units being analyzed for hydrocarbon potential (Mississippian and Pennsylvanian Systems), those that are the focus of hydrologic studies (Permian Wolfcamp Series and Permo-Triassic Dockum Group and Dewey Lake Formation), and the proposed waste repository horizon (Permian San Andres Formation). Work on other stratigraphic units is of lower priority and is being carried out peripherally. Table 1 indicates researchers responsible for contributions to this report and those who are continuing to study various stratigraphic units in the area.Bureau of Economic Geolog
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Integrated Outcrop and Subsurface Studies of the Interwell Environment of Carbonate Reservoirs: Clear Fork (Leonaradian Age) Reservoirs, West Texas and New Mexico, Semi-Annual
Outcrop studies include stratigraphic and petrophysical analysis. Analysis of the detailed sequence- and cycle-scale architecture of the Clear Fork reservoir-equivalent outcrops in Apache Canyon is nearly complete. This work reveals two high-frequency transgressive-regressive sequences (HFS) in the lower Clear Fork composite depositional sequence and three HFS in the basal middle Clear Fork composite depositional sequence. A 1,800-ft transect of 1-inch-diameter samples was collected from one cycle at the Apache Canyon outcrop. The transect was sampled with 5-ft spacing, but there were some gaps due to cover and cliff, resulting in 181 samples. Permeability, porosity, and grain density were measured, and the spatial statistics are being analyzed geostatistically
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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