Depositional model for the San Andres Formation, Roberts unit, Wasson field, Yoakum County, Texas

Conference · Wed Apr 01 00:00:00 EST 1992 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:7068212

Ginger, E P ^[1]

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1. Texaco Exploration and Production Technology Department, Houston, TX (United States)

The Permian San Andres reservoir at Roberts unit produces from approximately 250 ft of anhydritic dolostones. The reservoir interval, which is more than 500 ft below the top of the San Andres Formation, consists of fossiliferous and pelletal/peloidal dolowackestones and dolopackstones. They were deposited in a shallow-marine environment with local shoaling conditions. Toward the top of the reservoir, intertidal and supratidal deposits interfinger with the subtidal units and form the lateral and overlying seals. A sponge-bryozoan bank lithofacies is recognized within the subtidal deposits at Roberts unit. The banks consist of dolomitized mud-rich boundstones dominated by bryozoans, sponges, and crinoids. Interbedded fossiliferous dolowackestones, dolopackstones, and dolograinstones are common. The restricted nature of the San Andres in the western part of Roberts unit (i.e., shoreward of the banks) indicates that the banks baffled wave energy and inhibited current circulation on the platform, resulting in a mud-dominated, restricted lagoonal facies with very low faunal diversity. The sponge-bryozoan banks occur within a narrow belt across the central part of Roberts unit and continue into the adjacent Willard unit. Their distribution has a distinct northeast-soutwest trend that parallels the subjacent Abo shelf margin reef trend, suggesting that the Abo reef trend influenced subsequent bank development.

• OSTI ID: 7068212
• Report Number(s): CONF-9204139-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 76:4; Conference: American Association of Petroleum Geologists (AAPG) Southwest section meeting, Midland, TX (United States), 21-24 Apr 1992; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
NATURAL GAS DEPOSITS
GEOLOGIC MODELS
STRATIGRAPHY
PETROLEUM DEPOSITS
TEXAS
ANHYDRITE
DEPOSITION
DOLOMITE
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
LITHOLOGY
PERMIAN PERIOD
PETROLOGY
RESERVOIR ROCK
CARBONATE MINERALS
DEVELOPED COUNTRIES
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGY
MINERAL RESOURCES
MINERALS
NORTH AMERICA
PALEOZOIC ERA
RESOURCES
SULFATE MINERALS
USA
020200* - Petroleum- Reserves
Geology
& Exploration
030200 - Natural Gas- Reserves
Geology
& Exploration