Depositional environments, lithofacies types, and reservoir development of the Permian Khuff Formation in Eastern Saudi Arabia

Conference · Thu Aug 01 04:00:00 EDT 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5846774

Al-Jallal, I A ^[1]

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1. Saudi Aramco, Dhahran (Saudi Arabia)

The Later Permian carbonates and evaporites of the Khuff Formation contain considerable amounts of gas in Ghawar field, eastern Saudi Arabia. Sedimentary structures, textures, and grain types were used to interpret the depositional environments and to define the different lithofacies types which determine the original reservoir face is distribution within this 1,500-ft-thick formation. There are three major depositional environments: subtidal, intertidal, and sabkha. Locally, these include shoals, belts, bars, bays, lagoons, ponds, tidal channels, sabkha. Locally, these include shoals, belts, bars, bays, lagoons, ponds, tidal channels, sabkha islands, and sabkha pans. Tidal flooding and storms are represented. These environments represent four major transgressive-regressive cycles, which conform to four Khuff units: Khuff A, B, C and D (from youngest to oldest). Transgressive phases (subtidal), with lithofacies of grainstones and horizontally burrowed mudstones usually comprise the reservoir facies. The regressive phases (intertidal and sabkha) with lithofacies of anhydritic mudstones and anhydrites, usually seal the Khuff reservoirs. Later disappearance of reservoir facies are due to deposition or diagenesis. Depositionally, the lateral change in facies may occur, for example, from a non-reservoir anhydrite and mudstone facies to a reservoir grainstone facies, or from a non-reservoir anhydritic mudstones to a reservoir burrowed-mudstone facies. Diagenetically, ooid grainstones may be greatly cemented by anhydrite. A combination of dolomitization and leaching may create intercrystalline porosity in mudstone. Leaching creates poorly connected moldic porosity in grainstones because the resulting calcite cement plugs the interparticle porosity.

• OSTI ID: 5846774
• Report Number(s): CONF-910978--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 75:8
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
ASIA
CARBONATE ROCKS
DEPOSITION
DEVELOPING COUNTRIES
DIAGENESIS
EVAPORITES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGY
LITHOLOGY
MIDDLE EAST
MINERAL RESOURCES
NATURAL GAS DEPOSITS
PALEOZOIC ERA
PERMIAN PERIOD
PETROLEUM GEOLOGY
POROSITY
RESERVOIR ROCK
RESOURCES
ROCKS
SAUDI ARABIA
SEDIMENTARY ROCKS