Subsurface study of Lower Ordovician Prairie du Chien group and underlying Cambrian formations and their relation to pre-Glenwood unconformity in southern peninsula of Michigan
Prior to discovery of commercial gas in Lower Ordovician Prairie du Chien sandstones at Falmouth field, Missaukee County, in April 1981, only 119 wells had reached underlying Cambrian rocks in Michigan's Southern Peninsula. The resulting deep basin drilling activity to January 1, 1987, has resulted in 17 Prairie du Chien gas discoveries in the north-central part of the Michigan basin and an additional 46 Cambrian penetrations. This study also utilized 235 Prairie du Chien partial penetrations. It is now possible to correlate with relative certainty the standard Cambrian formations of the subsurface of southern Michigan to wells within and on the other margins of the basin. These, in ascending order, are Mount Simon, Eau Claire, Dresbach, Franconia, and Trempealeau. Because of the previous lack of control, these units were commonly misidentified in northern wells in previous studies. The present study largely corroborates previous recent work. Four ascending formations of the Prairie du Chien Group were also correlated throughout the basin: Umlor, Foster, Bruggers, and Goodwell (newly proposed). Two type wells demonstrate the character of the Goodwell Formation. The Bruggers Sandstones has been further divided into four informal zones, based on extending correlations of thin, silty dolomite marker beds on gamma-ray logs from the Goodwell and Woodville fields area, Newaygo County. Gas is produced from these Brugger zones. Twelve detailed stratigraphic cross sections (using 183 wells) and a pre-Glenwood paleogeologic map demonstrate marked basin-wide pre-Middle Ordovician erosional truncation.
- Research Organization:
- Diamond Shamrock Exploration Co., Denver, CO
- OSTI ID:
- 5864110
- Report Number(s):
- CONF-8710197-
- Journal Information:
- AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States), Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Vol. 71:9; ISSN AABUD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
030200* -- Natural Gas-- Reserves
Geology
& Exploration
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CAMBRIAN PERIOD
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
DOLOMITE
EXPLORATION
EXPLORATORY WELLS
FEDERAL REGION V
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGY
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MICHIGAN
MINERAL RESOURCES
MINERALS
NATURAL GAS DEPOSITS
NORTH AMERICA
ORDOVICIAN PERIOD
OXYGEN COMPOUNDS
PALEOZOIC ERA
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SILTSTONES
STRATIGRAPHY
USA
WELLS