Stratigraphic analysis of Prairie du Chien Group, Lower Peninsula, Michigan

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

OSTI ID:7041624

Rohr, S A; Prouty, C E

The Lower Ordovician Prairie du Chien Group of the Michigan basin has become a realistic target for hydrocarbon exploration. The New Richmond Sandstone and Shakopee dolomitic sandstone and dolomite part of the Wisconsin standard Prairie du Chien extend to the southeast through the Michigan basin with diminishing quartz sand content. Several distinct lithofacies are observed, including lagoonal, nearshore, offshore, and barrier-bar facies. The offshore barrier-bar model is interpreted as the most likely depositional environment for these sands. Prairie du Chien production has been limited to porous sandstones in structural traps. However, the porosity does not appear restricted to structures as previously believed. On the basis of considerable thin-section petrography, the sands appear to have primary porosity that escaped the detrimental pore-destroying effects of silica cementation. Porosity appears essentially intergranular and is closely associated with the clay minerals that occur as authigenic clay rims on framework grains. The association strongly suggests clay-mineral inhibition, growth of pore-occluding silica, or a combination of both. Other factors that probably directly or indirectly affected porosity retention are compaction, grain size, or presence of hydrocarbons; other factors considered of less importance are grain shape, grain edge, pore geometry, and pore location. The post-Knox erosional disconformity does not appear related to effective porosity below it (descending fluids); however, it places variable lithology beneath the Glenwood and is important regionally from stratigraphic and nomenclatural standpoints.

• Research Organization: Amoco Production Co., Houston, TX
• OSTI ID: 7041624
• Report Number(s): CONF-8610158-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 70:8
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
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& Exploration
CARBONATE ROCKS
CLAYS
EXPLORATION
FEDERAL REGION V
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
GEOLOGY
MICHIGAN
MINERAL RESOURCES
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PETROLEUM DEPOSITS
POROSITY
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
STRATIGRAPHY
USA