Depositional environments, sequence stratigraphy, and trapping mechanisms of Fall River Formation in Donkey Creek and Coyote Creek oil fields, Powder River basin, Wyoming

Conference · Fri Sep 01 00:00:00 EDT 1989 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:5631402

Knox, P R ^[1]

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1. Unocal, Santa Fe Springs, CA (USA)

Donkey Creek and Coyote Creek fields contain combined reserves of approximately 35 million bbl of oil and are within a trend of fields on the eastern flank of the Powder River basin that totals over 100 million bbl of reserves. The principal producing formation is the Lower Cretaceous Fall River Sandstone. A study of 45 cores and 248 logs from the three pools in the Donkey Creek and Coyote fields has shown that the Fall River is composed of three progradational deltaic units deposited during a period of rising relative sea level. These are locally eroded and are filled by a fluvial point-bar complex deposited following a lowering of relative sea level. Four important depositional facies have been recognized: the delta-front and distributary-channel sandstone of the highstand deltaic sequence and the point-bar sandstone and channel-abandonment of the lowstand fluvial sequence. Stratigraphic traps in Coyote Creek and south Donkey Creek pools are the result of permeable (250 md) point-bar sandstone (250 bbl oil/day ip) bounded updip by impermeable (0.1 md) channel abandonment mudstone. Most of the oil in the central Donkey Creek pool is produced from permeable (76 md) distributary-channel sandstone (150 bbl oil/day ip), which is restricted to the western flank of a structural nose. Lesser production, on the crest and upper western flank of the structure, is obtained from the less permeable (2.8 md) delta-front sandstone (50 bbl oil/day ip). Production is possibly limited to the crest and western flank by hydrodynamic processes.

• OSTI ID: 5631402
• Report Number(s): CONF-8910195-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 73:9; Conference: AAPG Rocky Mountain Section meeting, Albuquerque, NM (USA), 1-4 Oct 1989; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
OIL FIELDS
GEOLOGIC TRAPS
STRATIGRAPHY
POWDER RIVER BASIN
RESERVOIR ROCK
DEPOSITION
WYOMING
CRETACEOUS PERIOD
DIAGENESIS
GEOLOGIC FORMATIONS
PERMEABILITY
POROSITY
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGY
MESOZOIC ERA
MINERAL RESOURCES
MONTANA
NORTH AMERICA
PETROLEUM DEPOSITS
RESOURCES
USA
020200* - Petroleum- Reserves
Geology
& Exploration