Reservoir potential in Lower Devonian strata of Illinois

Conference · Tue Aug 01 00:00:00 EDT 1989 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:5460744

Whitaker, S T ^[1]

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1. Illinois State Geological Survey, Champaign (USA)

Lower Devonian strata have considerable potential for hydrocarbon reserves in the Illinois basin; however, there has not yet been a major exploration effort for Lower Devonian reservoirs in the basin, nor has an adequate model been developed to explain distribution of these reservoirs. Due to the lack of exploration, production from these strata is presently limited to a few fields in south-central and southwestern Illinois. A review of data available at the Illinois State Geological Survey indicates that most Lower Devonian production in Illinois is from dolomitized cherty limestones in the Clear Creek Formation and Grassy Knob Chert. Minor production has also been noted in similar facies in the Bailey Limestone. Reservoir development within these strata is caused by dolomitization of slightly porous limestone beds and occurs in proximity to the beds' subcrop at the sub-Kaskaskia (pre-Middle Devonian) unconformity. The best reservoir development appears to be along paleotopographic highs on the Lower Devonian surface. Traps are most commonly formed where porous dolomitic beds, truncated at the sub-Kaskaskia unconformity are underlain by tight cherty limestones and overlain by tight Middle Devonian carbonates. Traps may also be formed downdip from porosity truncations where trends of porous Lower Devonian strata coincide with structural closures. The geometry and distribution of known reservoirs and traps in Lower Devonian carbonates indicate there may be several productive fairways in the basin. Exploration for and exploitation of these plays will depend on an increased understanding of Lower Devonian strata utilizing exploration models such as the one presented here.

• OSTI ID: 5460744
• Report Number(s): CONF-8909166-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 73:8; Conference: American Association of Petroleum Geologists (AAPG) eastern section meeting, Blommington, IN (USA), 10-13 Sep 1989; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
ILLINOIS
PETROLEUM DEPOSITS
RESERVOIR ROCK
DEVONIAN PERIOD
DIAGENESIS
EXPLORATION
GEOLOGIC FORMATIONS
GEOLOGIC TRAPS
LIMESTONE
PERMEABILITY
POROSITY
CARBONATE ROCKS
FEDERAL REGION V
GEOLOGIC AGES
GEOLOGIC DEPOSITS
MINERAL RESOURCES
NORTH AMERICA
PALEOZOIC ERA
RESOURCES
ROCKS
SEDIMENTARY ROCKS
USA
020200* - Petroleum- Reserves
Geology
& Exploration