Geologic study and engineering review of Jurassic Smackover Formation of Thomasville field, Rankin County, Mississippi

Conference · Mon Sep 01 04:00:00 EDT 1986 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6884177

Shew, R D; Garner, M M

The Jurassic (Oxfordian) Smackover Formation in Thomasville field, Rankin County, Mississippi, produces sour gas from deep (19,000 + ft), geopressured (> 0.88 psi/ft) siliciclastics that are interbedded with nonreservoir carbonates. The siliciclastics are moderately to moderately well-sorted, fine to medium-grained subarkosic sandstones. They are characterized by low average porosities (7.0%) and permeabilities (0.35 md) resulting from both diagenetic and primary textural controls. Secondary and altered primary porosity are present. Permeability is reduced by several diagenetic events, including the formation of anthraxolite and authigenic fibrous illite. Smackover carbonate ramp deposition was interrupted in Thomasville by the periodic influx of siliciclastics. Siliciclastics were delivered to the basin of deposition by ancestral drainage systems and distributed on the ramp by current and storm processes. They are interpreted to be shallow marine (beach and bar), inner shelf (sand waves and storm deposits), and outer shelf to upper basinal (storm and turbidite channels) deposits based on sedimentary structures, trace fossils, and lateral and vertical facies association with the interbedded carbonates. The carbonates indicate a shoaling-upward sequence, with outer shelf and upper basinal mudstones and wackestones at the base grading upward through shelf packstones, high-energy ooid grainstone shoals, and asphalt intertidal mudstones to grainstones. Rock properties and interpretations of the depositional environments were based on core and drill-cutting analyses. These analyses supplemented the use of computer-enhanced wireline logs to establish rock-log calibrations, correlation markers, structural growth, and reservoir continuity.

• Research Organization: Shell Development, Houston, TX
• OSTI ID: 6884177
• Report Number(s): CONF-8610199-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 70:9
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
CLAYS
DIAGENESIS
FEDERAL REGION IV
GEOLOGIC AGES
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GEOLOGIC FORMATIONS
GEOLOGY
JURASSIC PERIOD
MESOZOIC ERA
MINERAL RESOURCES
MISSISSIPPI
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PERMEABILITY
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RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
USA