Controls on porosity development in the Devonian Reservoir at Dolarhide Field

Conference · Tue May 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6916668

Saller, A; Miller, J ^[1]; Van Horn, D ^[2]

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1. Unocal Science and Technology, Brea, CA (USA)
2. Unocal Oil and Gas, Farmington, NM (USA)

Devonian strata in the Dollarhide anticline originally contained 138 million bbl of oil. Porosity distribution is controlled by depositional facies. Devonian shata contain five main lithologies (from bottom to top). (1) Nonporous, microcrystalline chert and dolomite deposited as carbonate and siliceous mud in a basinal enviroment. (2) Burrowed chert-dolomite (10-35 ft thick) with variable porosity accumulated as siliceous sponge spicules and carbonate mud in a low-energy slope environment. (3) Laminated tripolitic chert (0-65 ft) deposited as a spiculitic sand in submarine channels in a slope environment. It has excellent porosity, mainly molds of sponge spicules. (4) Bioclastic limestone (47-92 ft) accumulated as a crinoidal grainstone in a moderate- to high-energy, outer shelf environment. Calcite cementation occluded virtually all porosity. (5) Upper dolomite (50-90 ft) consists of 1-3-ft-thick sequences of dolomitized peloidal grainstone capped by fine-grained chert. The grainstone was deposited in high-energy, shallow-subtidal and tidal-flat environments and has variable porosity. Deposition of the 200-ft-thick Devonian section occurred during a major progradation of shelf and slope facies. Porosity occurs in two stratigraphic zones separated by tight bioclastic limestone. The upper porosity zone (0-90 ft in upper dolomite) is heterogeneous with stratified porosity that bifurcates, coalesces, and pinches out. The lower porosity zone (laminated tripolitic chert and burrowed chert-dolomite) is homogeneous, with high porosity (commonly 25-35%), moderate permeability (5-20 md), and, in the southern part of the field, no distinct vertical permeability barriers. Thickness of the lower reservoir is variable (0-100 ft) with elongate thicks where sponge spicule sands filled channels.

• OSTI ID: 6916668
• Report Number(s): CONF-900605--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
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58 GEOSCIENCES
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ANTICLINES
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CHERT
DEVONIAN PERIOD
DOLOMITE
FEDERAL REGION VI
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GEOLOGIC TRAPS
MAGNESIUM CARBONATES
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NORTH AMERICA
OXYGEN COMPOUNDS
PALEOZOIC ERA
PETROLEUM DEPOSITS
POROSITY
RESERVOIR ROCK
RESOURCES
ROCKS
SEDIMENTARY ROCKS
USA