Depositional setting, structural style, and sandstone distribution in three geopressured geothermal areas, Texas Gulf Coast

Technical Report · Sat Jan 01 00:00:00 EST 1983

DOI:https://doi.org/10.2172/5875562· OSTI ID:5875562

Winker, C D; Morton, R A; Ewing, T E; Garcia, D D

Three areas in the Texas Gulf Coastal Plain were studied using electric logs and seismic-reflection data to interpret their depositional and structural history and to compare their potential as geopressured-geothermal reservoirs. The Cuero study area, on the lower Wilcox (upper Paleocene) growth-fault trend, is characterized by closely and evenly spaced, subparallel, down-to-the-basin growth faults, relatively small expansion ratios, and minor block rotation. Distributary-channel sandstones in the geopressured lower Wilcox Group of the South Cook fault block appear to be the best geothermal aquifers in the Cuero area. The Blessing study area, on the lower Frio (Oligocene) growth-fault trend, shows wider and more variable fault spacing and much greater expansion ratios and block rotation, particularly during early Frio time. Thick geopressured sandstone aquifers are laterally more extensive in the Blessing area than in the Cuero area. The Pleasant Bayou study area, like the Blessing area, is on the Frio growth-fault trand, and its early structural development was similar rapid movement of widely spaced faults resulted in large expansion ratios and major block rotation. However, a late-stage pattern of salt uplift and withdrawal complicated the structural style. Thick geopressured lower Frio sandstone aquifers are highly permeable and laterally extensive, as in the Blessing area. In all three areas, geopressured aquifers were created where early, rapid movement along down-to-the-basin growth faults juxtaposed shallow-water sands against older shales, probably deposited in slope environments. Major transgressions followed the deposition of reservoir sands and probably also influenced the hydraulic isolation that allowed the build up of abnormal pressures. 26 refs., 49 figs., 8 tabs.

• Research Organization: Texas Univ., Austin (USA). Bureau of Economic Geology
• DOE Contract Number: AC08-79ET27111; AS05-76ET28461
• OSTI ID: 5875562
• Report Number(s): DOE/ET/27111-T6; ON: DE85009787
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products. Report of Investigations No. 134
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
58 GEOSCIENCES
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STRATIGRAPHY
TEXAS
GEOTHERMAL RESOURCES
HOT-WATER SYSTEMS
COASTAL REGIONS
ELECTRIC LOGGING
GEOLOGIC FAULTS
SANDSTONES
SEDIMENTARY BASINS
SEISMIC SURVEYS
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GEOLOGIC FRACTURES
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WELL LOGGING
Geothermal Legacy