Unconformity related traps and production, Lower Cretaceous through Mississippian Strata, central and northern Rocky Mountains

Conference · Tue May 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:7091782

Dolson, J ^[1]

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1. Amoco Production Co., Denver, CO (USA)

Unconformities provide a useful means of equating stratigraphic traps between basins. Systematic mapping can define new concepts through analogy, often from geographically separate areas. Lower Cretaceous through Mississippian surfaces in the central and northern Rockies provide examples. Late Mississippian and Early Pennsylvanian surfaces formed at least four paleodrainage basins separated by the Transcontinental arch. Tyler Formation valley fills (Montana, North Dakota) have produced more than 100 million BOE. Analogous targets in Utah remain untested, but the Mid-Continent Morrow trend continues to yield new reserves. Permian and Triassic paleodrainages filled primarily with seals and form regional traps. A breached Madison trap (Mississippian, Colorado), more than 350 million BOE (Permian Minnelusa, Wyoming), more than 8 billion BOE (from the White Rim Sandstone tar deposits Permian Utah), and eastern Williston basin (Mississippian) are examples. Minor basal valley fill trapping also occurs. Transgressive carbonate facies changes have trapped more than 40 million BOE (Permian Phosphoria Formation, Wyoming). Additional deep gas potential exists. Jurassic unconformities control seal distribution over Nugget Sandstone (Jurassic) reservoirs and partially control Mississippian porosity on the Sweetgrass arch (Montana). Minor paleohill trapping also occurs. Lower Cretaceous surfaces have trapped nearly 2 billion BOE hydrocarbons in 10 paleodrainage networks. Undrilled paleodrainage basins remain deep gas targets. The systematic examination of Rocky Mountain unconformities has been understudied. New exploration concepts and reserve additions await the creative interpreter.

• OSTI ID: 7091782
• Report Number(s): CONF-900605--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
CARBONIFEROUS PERIOD
CRETACEOUS PERIOD
EXPLORATION
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
GEOLOGIC TRAPS
MESOZOIC ERA
MINERAL RESOURCES
MOUNTAINS
NORTH AMERICA
PALEOZOIC ERA
PERMEABILITY
PERMIAN PERIOD
PETROLEUM DEPOSITS
POROSITY
RESERVOIR ROCK
RESOURCES
ROCKS
ROCKY MOUNTAINS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
TRIASSIC PERIOD
USA
WYOMING