Stratigraphy of the Lower Cretaceous Muddy Formation and the drainage pattern of its paleovalleys, Wind River basin, Wyoming

Conference · Fri Mar 01 04:00:00 EST 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:7079473

Bold, M.C. van den ^[1]; Johnson, S R; Gustason, E R ^[2]

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1. BP Exploration, Houston, TX (United States)
2. BP Exploration, Anchorage, AK (United States)

Valley-fill deposits of the Lower Cretaceous Muddy Sandstone contain significant stratigraphically trapped hydrocarbon accumulations and are an important exploration target in Wyoming's Bighorn, Powder River, and eastern Wind River basins. An integrated subsurface and outcrop study of the Muddy Sandstone in the western Wind River basin was conducted in order to determine (1) if Muddy paleovalleys and are present there, (2) if potential for stratigraphic traps exists, and (3) if source rocks of sufficient quality and maturity are able to charge the Muddy reservoirs. The results of the study reveal that the Muddy Sandstone (up to 100 ft thick) contains a series of unconformity bounded progradational shoreface deposits, separated by a valley-fill sequence (up to 60 ft thick). In general, the Muddy Formation is divided into three informal zones: (1) a lower marine zone, containing at least two progradational shoreface highstand parasequences; (2) a middle zone, which consists of a lowstand fluvial/estuarine valley-fill sequence (8-10 mi wide); and (3) an upper marine zone, containing at least three landward-stepping highstand shoreface parasequences. In the southwestern Wind River Basin, the Muddy paleovalley trend is north-northwest, parallel to the present-day structural trend of the Wind River thrust and its parasitic anticlines. However, instead of continuing into the potentially prospective northwestern Wind River basin, the paleovalley makes an abrupt 90{degree} turn westward, a few miles north of Ft. Washakie. A detailed understanding of how Muddy paleovalley drainage reacts to basement faults could become a key predictive tool for future Muddy exploration in the northern Rocky Mountains.

• OSTI ID: 7079473
• Report Number(s): CONF-910403--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 75:3
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
CRETACEOUS PERIOD
DEPOSITION
DEVELOPED COUNTRIES
EXPLORATION
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGIC TRAPS
GEOLOGY
MESOZOIC ERA
MINERAL RESOURCES
NORTH AMERICA
PETROLEUM DEPOSITS
PETROLEUM GEOLOGY
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SOURCE ROCKS
STRATIGRAPHY
USA
WYOMING