Rock types, pore types, and hydrocarbon exploration

Conference · Wed May 01 04:00:00 EDT 1985 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:5992724

Coalson, E B; Hartmann, D J; Thomas, J B

A proposed exploration-oriented method of classifying porosity in sedimentary rocks is based on microscopic examination cores or cuttings. Factors include geometry, size, abundance, and connectivity of the pores. The porosity classification is predictive of key petrophysical characteristics: porosity-permeability relationships, capillary pressures, and (less certainly) relative permeabilities. For instance, intercrystalline macroporosity typically is associated with high permeability for a given porosity, low capillarity, and favorable relative permeabilities. This is found to be true whether this porosity type occurs in a sucrosic dolomite or in a sandstone with pervasive quartz overgrowths. This predictive method was applied in three Rocky Mountain oil plays. Subtle pore throat traps could be recognized in the J sandstone (Cretaceous) in the Denver basin of Colorado by means of porosity permeability plotting. Variations in hydrocarbon productivity from a Teapot Formation (Cretaceous) field in the Powder River basin of Wyoming were related to porosity types and microfacies; the relationships were applied to exploration. Rock and porosity typing in the Red River Formation (Ordovician) reconciled apparent inconsistencies between drill-stem test, log, and mud-log data from a Williston basin wildcat. The well was reevaluated and completed successfully, resulting in a new field discovery. In each of these three examples, petrophysics was fundamental for proper evaluation of wildcat wells and exploration plays.

• Research Organization: Bass Enterprises Production Co., Denver, CO
• OSTI ID: 5992724
• Report Number(s): CONF-8506201-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 69:5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
COLORADO
CRETACEOUS PERIOD
DRILLING
EXPLORATION
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
MESOZOIC ERA
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NORTH AMERICA
ORDOVICIAN PERIOD
PALEOZOIC ERA
PERMEABILITY
PETROLEUM DEPOSITS
POROSITY
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
USA
WELL DRILLING
WILLISTON BASIN
WYOMING