Middle Devonian Winnipegosis reefs of Tableland area, southeast Saskatchewan

Conference · Fri Jul 01 04:00:00 EDT 1988 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:6180022

Martindale, B; Orr, N

In 1986, Home Oil drilled the first of several hydrocarbon-bearing Winnipegosis reefs in the southeastern part of the Elk Point basin in Saskatchewan. The discovery well, 8A-22-2-9W2, initially flowed 37/degrees/ API oil at 223 m/sup 3//day (1400 bbl/day) from a dolomitized buildup estimated to be 70 m thick. This well was located using conventional two-dimensional and seismic modeling techniques. A pseudo 3-D survey, using the existing grid of 2-D data, was used to locate subsequent wells. The reef consists of a basal fossiliferous mound with steep cemented flanks and directly overlies the lower Winnipegosis platform. This basal mound is overlain by a series of coalesced peloid and codiacean algal grainstone shoals, also with steep cemented margins. The shoals are capped by a framestone unit of branched corals and stromatoporoids in a lagoonal position and by a boundstone unit of blue-green and red algae forming a reef crest. Dolomitic laminites of the Ratner Member (upper Winnipegosis lower Prairie Evaporite) overlie the reef flank and occur between reef complexes in basinal areas. These laminites, in turn, are overlain by anhydrites and halites of the Prairie Evaporite Formation. The reef in the Tableland area is characterized by a fauna of high abundance and low diversity, both indicative of growth in a stressed, probably hypersaline, environment. Reservoir quality of the Winnipegosis depends both on original depositional facies and subsequent diagenetic events. Although extensively dolomitized, both shallow and deep diagenetic fabrics can be recognized. Oil source rock correlations prove that the hydrocarbons in the Tableland reef are locally sourced from bituminous mudstones of the Ratner Member.

• Research Organization: Home Oil Co. Ltd., Calgary, Alberta (Canada)
• OSTI ID: 6180022
• Report Number(s): CONF-8808223-
• Conference Information: Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Journal Volume: 72:7
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CANADA
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
DEPOSITION
DOLOMITE
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MINERAL RESOURCES
MINERALS
NORTH AMERICA
OXYGEN COMPOUNDS
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
SASKATCHEWAN
SEDIMENTARY BASINS
SEISMIC SURVEYS
SOURCE ROCKS
SURVEYS