Evaluation of evaporite facies as a tool for exploration, Yates Field, Texas

Conference · Fri May 01 04:00:00 EDT 1987 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:5771827

Spencer, A W; Warren, J K

Evaporites have long been recognized as the most efficient reservoir seal; however, the seal can itself serve as an exploration tool to locate subtle stratigraphic traps. By analogy with modern environments, thick massive evaporites form subaqueously in ponds (salinas) in topographic lows while sabkhas form on the subaerially exposed supratidal zone on topographic highs. Recognition of evaporite facies distribution can delineate paleotopography where sabkhas form a seal over local highs and closure is provided by salinas forming a lateral seal in lows. These relationships are illustrated by the giant Yates field (2 billion bbl reserves), situated at the southern tip of the Central basin platform in the Permian basin. The seal over the Yates reservoir (San Andres formation) is formed by the evaporites at the base of the Seven Rivers Formation (Guadalupian). Within the evaporite, two distinct depositional facies are recognized: a massive, salina-anhydrite in the central and western parts of the field; and on the east, stacked sabkha sequences consisting of sandy dolomite overlying a sharp base, grading into nodular anhydrite and capped by an erosional surface. The depositional topography on the underlying San Andres reservoir controlled the facies distribution in the basal Seven Rivers. Carbonate buildups formed on the eastern side of the field, while interbedded shales and dolomites accumulated in the quiet lagoonal waters behind. Due to dewatering and compaction during early burial, the lagoons remained topographically low until early Seven Rivers time when they were finally filled with salina evaporites. The rigid shelf margin buildups remained as topographic highs over which sabkhas developed. Only 10% of the production has come from the lagoonal muds under the salinas, while 90% has been produced from the carbonate buildups under the sabkhas.

• Research Organization: Univ. of Texas, Austin
• OSTI ID: 5771827
• Report Number(s): CONF-870606-
• Conference Information: Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Journal Volume: 71:5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
DOLOMITE
EVAPORITES
EXPLORATION
FEDERAL REGION VI
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC TRAPS
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MINERAL RESOURCES
MINERALS
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OIL FIELDS
OXYGEN COMPOUNDS
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SHALES
TEXAS
USA