Facies, faults and potential sweet spots in a tight gas reservoir: Almond Formation, Wyoming

Conference · Mon Jan 01 00:00:00 EST 1996 · AAPG Bulletin

OSTI ID:6582715

Martinsen, R; Iverson, W; Surdam, R ^[1]

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1. Univ. of Wyoming, Laramie, WY (United States)

The Almond Formation is a major producer of gas in southwestern Wyoming. Although exploration generally is aimed at finding conventional reservoirs in upper Almond marine sandstones, the majority of Almond gas is contained in the underlying main Almond, a succession of dominantly non-marine, interbedded tight sandstones, siltstones, carbonaceous shales and coals. Production data indicate that some of the best gas wells completed in upper Almond sands show little production decline and have already produced more gas than calculations indicate they contain. This implies that these wells have somehow successfully tapped into the vast supply of gas contained in the main Almond. We believe that the more permeable reservoirs, in addition to providing [open quotes]sweet spots[close quotes] for exploration, also serve as lateral conduits capable of draining gas over a broad area from the main Almond. The [open quotes]sweet spots[close quotes] themselves do not need to be volumetrically large, only permeable and laterally continuous. Previously unrecognized marine sands, similar to those in the upper Almond, are favorably located in the middle of the main Almond succession and may provide additional lateral conduits. Studies also show that syndepositional faults significantly influenced deposition and may also be important in terms of fluid flow. At least some syndepositional faults are associated with anomalously high gas and/or water production within fields, and may be vertical conduits for fluid flow.

• OSTI ID: 6582715
• Report Number(s): CONF-960527-; CODEN: AABUD2
• Journal Information: AAPG Bulletin, Vol. 5; Conference: Annual convention of the American Association of Petroleum Geologists, Inc. and the Society for Sedimentary Geology: global exploration and geotechnology, San Diego, CA (United States), 19-22 May 1996; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
NATURAL GAS
PRODUCTION
RESERVOIR ROCK
FLUID FLOW
PERMEABILITY
WYOMING
NATURAL GAS DEPOSITS
STRATIGRAPHY
GEOLOGIC FAULTS
DEVELOPED COUNTRIES
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GEOLOGIC DEPOSITS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
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030200* - Natural Gas- Reserves
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& Exploration