Factors controlling reservoir quality in tertiary sandstones and their significance to geopressured geothermal production. Annual report, May 1, 1979-May 31, 1980
Differing extents of diagenetic modification is the factor primarily responsible for contrasting regional reservoir quality of Tertiary sandstones from the Upper and Lower Texas Gulf Coast. Detailed comparison of Frio sandstones from the Chocolate Bayou/Danbury Dome area, Brazoria County, and Vicksburg sandstones from the McAllen Ranch Field area, Hidalgo County, reveals that extent of diagenetic modification is most strongly influenced by (1) detrital mineralogy and (2) regional geothermal gradients. Vicksburg sandstones from the McAllen Ranch Field area are less stable, chemically and mechanically, than Frio sandstones from the Chocolate Bayou/Danbury dome area. Vicksburg sandstones are mineralogically immature and contain greater proportions of feldspars and rock fragments than do Frio sandstones. Thr reactive detrital assemblage of Vicksubrg sandstones is highly susceptible to diagenetic modification. Susceptibility is enhanced by higher than normal geothermal gradients in the McAllen Ranch Field area. Thus, consolidation of Vicksburg sandstones began at shallower depth of burial and precipitation of authigenic phases (especially calcite) was more pervasive than in Frio sandstones. Moreover, the late-stage episode of ferroan calcite precipitation that occluded most secondary porosity in Vicksburg sandstones did not occur significantly in Frio sandstones. Therefore, regional reservoir quality of Frio sandstones from Brazoria County is far better than that characterizing Vicksburg sandstones from Hidalgo County, especially at depths suitable for geopressured geothermal energy production.
- Research Organization:
- Texas Univ., Austin (USA). Bureau of Economic Geology
- DOE Contract Number:
- AC08-79ET27111
- OSTI ID:
- 6870346
- Report Number(s):
- DOE/ET/27111-1
- Country of Publication:
- United States
- Language:
- English
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ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CARBON COMPOUNDS
CARBON ISOTOPES
CARBONATES
CHALCOGENIDES
DIAGENESIS
FELDSPARS
GEOPRESSURED SYSTEMS
GULF COAST
Geothermal Legacy
IRON COMPOUNDS
IRON OXIDES
ISOTOPES
KAOLINITE
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MINERALOGY
MINERALS
MODIFICATIONS
NORTH AMERICA
OXIDES
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
POROSITY
POTASSIUM COMPOUNDS
POTASSIUM OXIDES
PRESSURE GRADIENTS
QUARTZ
RESERVOIR ROCK
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SILICATES
SILICON COMPOUNDS
SILICON OXIDES
SODIUM COMPOUNDS
SODIUM OXIDES
SOUTHWEST REGION
STABILITY
TEMPERATURE GRADIENTS
TEXAS
TRANSITION ELEMENT COMPOUNDS
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