--> Abstract: The Keg River/Winnipegosis Petroleum System--Source to Trap Part I, by S. W. Tinker and K. C. Kirkby; #91004 (1991)

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The Keg River/Winnipegosis Petroleum System--Source to Trap Part I

TINKER, SCOTT W., Marathon Oil Company, Littleton, CO, and KENT C. KIRKBY, University of Wisconsin, Madison, WI

This study (presented in two parts) integrates core data (125 cores), standard and epifluorescence petrography (450 thin sections), logs, and seismic and source rock/oil geochemisty in order to evaluate the Keg River/Winnipegosis petroleum system. Important results include (1) the interpretation of the regional depositional and stratigraphic framework of the Middle Devonian (Givetian) Keg River/Winnipegosis Formation from northwest Alberta 1100 mi (1770 km) southeast to North Dakota, (2) re-examination of trap types in the Keg River/Winnipegosis, (3) evaluation of source rock(s) and migration pathway(s) for known Keg River/Winnipegosis production, and (4) high-grading of old and new play types.

Early Devonian (pre-Keg River time) was dominated by multiple-cycle evaporite deposition ending with deposition of planar anhydrites of the Chinchaga Formation and shales of the Ashern Formation. The lower Keg River/Winnipegosis was deposited in shallow water (<250 ft or <76 m) as a carbonate ramp. Contemporaneous faulting and uplift during Middle Devonian time initiated development of a platform margin composed of stacked, porous (15-25%) packstone and grainstone shoals. Pinnacle and bank growth in the basin was contemporaneous with shelf deposition. Keg River/Winnipegosis deposition ended with restriction of the basin and subsequent deposition of the Muskeg/Prairie Formation evaporites. These evaporites act as the seal for most Keg River/Winnipegosis production.

The Keg River/Winnipegosis produces hydrocarbons from a variety of trap types including pinnacle reefs in the Rainbow/Zama subbasin (>650 MMBO cum.) and in southern Saskatchewan (>2 MMBO cum.); shelf-margin carbonates at Temple field (>3 MMBO cum.); middle shelf carbonates at Senex (>2 MMBO cum.); inner shelf carbonates in northeastern Montana, southern Saskatchewan, and southern Alberta (>10 MMBO cum.); and inner shelf siliciclastics at Utikima Lake (>75 MMBO cum.). There is great potential for significant additional Keg River hydrocarbon reserves in the outer shelf margin of Alberta and the pinnacle basin of North Dakota.

 

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)