Upper Devonian First Bradford formation of southwestern Pennsylvania: environment of deposition and factors affecting gas production

Conference · Sat Dec 01 04:00:00 EST 1984 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:5849263

Murin, T M; Donahue, J

Core descriptions and thin-section analyses from five wells in southwestern Pennsylvania, in addition to regional cross sections and subsurface maps, provide the basis for subdividing the Upper Devonian First Bradford formation into three distinct members. Isopach maps show the sandstones to be strike-oriented linear ridges and/or pods 1-3 km (0.6-1.9 mi) wide and 3-20 km (1.9-12.4 mi) long. Thicknesses rarely exceed 10 m (33 ft). Regionally, sand percentage for the overall interval (approximately 46 m or 151 ft) decreases west and southwest of Clearfield County where only the lower sandstone is preserved in parts of Armstrong and Westmoreland Counties. The postulated depositional environment is a shallow marine, inner to mid-shelf bar facies. The sediments accumulated as a result of current reworking; in places, deposition was controlled by shelf topography. Sediments were probably derived from a deltaic complex in the vicinity of Clearfield County. Gas production is confined to the stratigraphic limits of the clean sandstones and is locally enhanced by a high structural position. This combination trapping permits the segregation of gas and water and is evidenced by production in Westmoreland and Fayette Counties. Core porosities average 6.7%; permeability, with an effective overburden pressure of 1000 psi (6895 kPa), average 0.04 md. Production capabilities are ultimately affected by various diagenetic influences, which include compaction, cementation, authigenesis, replacement, and leaching.

• Research Organization: Univ. of Pittsburgh, PA
• OSTI ID: 5849263
• Report Number(s): CONF-8410269-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 68:12
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
DEPOSITION
DEVONIAN PERIOD
DIAGENESIS
ENERGY SOURCES
FEDERAL REGION III
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC TRAPS
GEOLOGY
LITHOLOGY
MINERAL RESOURCES
NATURAL GAS
NATURAL GAS DEPOSITS
NORTH AMERICA
PALEOZOIC ERA
PENNSYLVANIA
PRODUCTION
RESERVOIR ROCK
RESOURCE POTENTIAL
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
STRATIGRAPHY
USA