Differential entrapment of oil and gas in Niagaran pinnacle-reef belt of Northern Michigan

Journal Article · Sun Apr 01 04:00:00 EST 1979 · Am. Assoc. Pet. Geol. Bull.; (United States)

OSTI ID:5630657

Gill, D

The Niagaran pinnacle-reef belt in the northern part of the Michigan basin is about 170 mi (270 km long) and 10 to 20 mi (16 to 32 km) wide. Since 1969, 360 oil- and gas-producing reefs and 72 salt-plugged or otherwise barren, water-saturated reefs have been found in the belt. The reefs are of small areal extent (average 80 acres; 32 ha.), high relief (up to 600 ft; 180 m), and steep flanks (30 to 45/sup 0/) and are effectively sealed by the lower Salina evaporite deposits. The reefs are hydraulically interconnected through the Lockport Formation, their common permeable substrate, which dips basinward at 70 to 140 ft/mi (13 to 26 m/km; 0.76 to 1.52/sup 0/). Reef height, pay thickness, burial depth, reservoir pressure, hydrogen sulfide content, and extent of salt plugging increase progressively in a basinward direction across the belt, whereas oil gravity and degree of dolomitization increase systematically in the opposite direction. The belt is distinctly partitioned in a updip direction into three parallel bands of gas-, oil-, and water-saturated zones. This zonation of reservoir fluids is in full accord with Gussow's classic theory on the differential entrapment of oil and gas and provides a textbook example of its applicability on a regional scale in a natural case history. Interruptions in the continuity of the water-saturated band are interpreted as indicating passageways through which hydrocarbons may have migrated farther updip into the carbonate-shelf platform bounding the pinnacle-reef belt on the north. This reasoning leads to the delineation of two additional favorable target areas for further exploration.

• Research Organization: Geological Survey of Israel, Jerusalem
• OSTI ID: 5630657
• Journal Information: Am. Assoc. Pet. Geol. Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol. Bull.; (United States) Vol. 63:4; ISSN AAPGB
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200 -- Petroleum-- Reserves
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& Exploration
03 NATURAL GAS
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CARBONATE ROCKS
FLUIDS
GAS CONDENSATE FIELDS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GEOLOGIC TRAPS
GREAT LAKES REGION
MICHIGAN
MIGRATION
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OIL FIELDS
PALEOZOIC ERA
PETROLEUM DEPOSITS
RESERVOIR FLUIDS
RESERVOIR ROCK
RESOURCES
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SEGREGATION
SILURIAN PERIOD
USA