The structural history of the Brady Unit, Sweetwater County, Wyoming

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · AAPG Bulletin

OSTI ID:86651

Folcik, J L; Mead, R H ^[1]

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1. Union Pacific Resources Co., Fort Worth, TX (United States)

The Brady Unit is a 100MMBOE+, structural closure on the upthrown side of a large high-angle reverse fault on the east flank of the Rock Springs Uplift. It produces from seven different intervals ranging from the Upper Cretaceous Masaverde Group to the Pennsylvainian Weber Formation, at depths of 5000` to 14000`. The Weber Formation is a 900` thick package of dune and interdune sediments which is productive in its upper third. The south structure is filled close to it`s spill point with a retrograde condensate. Condensate gravity is approximately 51.5{degrees} and a typical initial GOR is 5000:1. The north structure has an unknown gas column with an initial GOR of 27,900:1. The Upper Jurassic Entrada Formation consists of eolian, interdune and shoreline sandstones. The enigmatic nature of the Entrada at Brady stews from the fact that it has a gas column of at least 180` in the lower north structure and it is porous and wet in the higher south structure. This difference becomes are curious when coupled with the fact that five other formations, both younger and older produce on both structures. A 3-D seismic survey was shot over Brady in 1993. Isochrons indicate that the north structure existed prior to Madison deposition. The south structure didn`t become significant until the Upper Cretaceous. The structural history as indicated by a series of isochrons is used to explain the differences in hydrocarbon content of the two structures.

• OSTI ID: 86651
• Report Number(s): CONF-9507131--
• Journal Information: AAPG Bulletin, Journal Name: AAPG Bulletin Journal Issue: 6 Vol. 79; ISSN 0149-1423; ISSN AABUD2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
GEOLOGIC STRUCTURES
HYDROCARBONS
NATURAL GAS
OIL FIELDS
PETROLEUM
PRODUCTION
SANDSTONES
SEISMIC SURVEYS
WYOMING