Thermal maturity, porosity, and facies relationships applied to gas generation and production in Tertiary and Cretaceous low-permeability sandstones, Uinta basin, Utah

Conference · Sat Jun 01 04:00:00 EDT 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:6003419

Nuccio, V F; Schmoker, J W; Fouch, T D ^[1]

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1. Geological Survey, Denver, CO (United States)

Uinta basin rocks include a thick sequence of low-permeability (tight) sandstones that contain a large volume of gas. Most known gas accumulations occur in the eastern part of the basin in the Upper Cretaceous Mesaverde Group; uppermost Cretaceous to early Eocene North Horn Formation; and the Paleocene and Eocene Wasatch, Colton, and Green River formations. Most successful tight-gas completions are in Tertiary strata, but rocks in the underlying, largely undrilled Mesaverde Group in the north-central part of the basin are potential targets as well. To characterize the gas-bearing sandstones, the authors have constructed a series of interrelated maps and cross sections showing thermal maturity, porosity, fluid pressures, and lithofacies relations for the Uinta basin. Vitrinite reflectance (R{sub m}) for each of these low-permeability sequence increases to the north and levels of thermal maturation are sufficient for gas generation over large areas of the basin. Projection of maturity values and fluid-pressure data into undrilled parts of the basin reveals the probability of a regional, overpressured, basin-entered gas accumulation, where gas is likely to be generating at present. Plots of porosity vs. R{sub m} allow prediction of porosity for Mesaverde sandstones in unexplored areas of the basin. The authors data indicates a large area of organic-rich, overpressured strata probably underlies the northern part of the Uinta basin. Wells drilled in the Mesaverde and lower part of the Tertiary, in the areas where R{sub m} at the base of the Mesaverde is greater than 1.1%, should have the best potential for gas production. Overpressured gas reservoirs are likely to have no free water and be enveloped by successive zones of mixed water and gas and of water only.

• OSTI ID: 6003419
• Report Number(s): CONF-9107109--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 75:6
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
CENOZOIC ERA
CRETACEOUS PERIOD
DEVELOPED COUNTRIES
ENERGY SOURCES
FEDERAL REGION VIII
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGY
GEOPRESSURED SYSTEMS
LITHOLOGY
MATURATION
MESOZOIC ERA
MINERAL RESOURCES
NATURAL GAS
NATURAL GAS DEPOSITS
NORTH AMERICA
OPTICAL PROPERTIES
PERMEABILITY
PHYSICAL PROPERTIES
PORE PRESSURE
POROSITY
RESERVOIR PRESSURE
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SPECTRAL REFLECTANCE
STRATIGRAPHY
TERTIARY PERIOD
UINTA BASIN
USA
UTAH