Sequence stratigraphy interpretation of the Ervay member (Permian, Park City Formation), west-central Wyoming paleoshelf

Conference · Fri Mar 01 00:00:00 EST 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5875308

Clark, W J; Hurley, N F ^[1]; Choquette, P W; Hiatt, E E; Garfield, T R; Budd, D A ^[2]

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1. Marathon Oil Co., Littleton, CO (United States)
2. Univ. of Colorado, Boulder (United States)

The Park City Formation is an important unconformity-bounded, Upper Permian stratigraphic sequence. Established lithostratigraphic correlations within the unit can be reinterpreted within a sequence stratigraphic framework. Three major carbonate-rich parasequences occur. From bottom to top, these are the Grandeur, Franson, and Ervay. The Ervay is the main hydrocarbon-producing unit within the Park City. In the study area it generally consists of low-energy, restricted-to open-marine wackestones and packstones deposited that ranges from a submarine omission surface to an erosional exposure surface. The upper boundary is the Permo-Triassic regional unconformity. The Ervay exhibits several transgressive surfaces and possible thin condensed zones in cores and outcrops. These features, which commonly appear as high gamma-ray markers on logs, are characterized by phosphatic and skeletal lags, marine hardgrounds, and glauconite. Log correlations of these features allow stratal geometries to be determined. In the lower Ervay, transgressive units appear to onlap eastward. In the upper Ervay, geometries are primarily aggradational. Most Ervay hydrocarbon production is from structural traps. In at least one field, however, updip stratigraphic pinch-outs form traps. At a regional scale, or in analogous systems, the sequence stratigraphic approach may help define other pinch-outs, dolomitized trends, fairways of grainier facies, and areas where source and reservoir rocks are juxtaposed. The sequence stratigraphy of the Ervay parasequence also helps explain the complex reservoir zonations found throughout the study area.

• OSTI ID: 5875308
• Report Number(s): CONF-910403-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 75:3; Conference: Annual meeting of the American Association of Petroleum Geologists (AAPG), Dallas, TX (United States), 7-10 Apr 1991; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
NATURAL GAS DEPOSITS
RESERVOIR ROCK
STRATIGRAPHY
PETROLEUM DEPOSITS
LITHOLOGY
WYOMING
CARBONATE ROCKS
GEOLOGIC FORMATIONS
GEOLOGIC TRAPS
PERMIAN PERIOD
PETROLEUM GEOLOGY
DEVELOPED COUNTRIES
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGY
MINERAL RESOURCES
NORTH AMERICA
PALEOZOIC ERA
RESOURCES
ROCKS
SEDIMENTARY ROCKS
USA
020200* - Petroleum- Reserves
Geology
& Exploration
030200 - Natural Gas- Reserves
Geology
& Exploration