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Deep Basin >> Overview

Deep Basin Overview

The prolific Deep Basin parallels the western edge or structural "foredeep" of the Western Canada Sedimentary Basin (WCSB) and forms a regionally extensive area of hydrocarbon-saturated, abnormally pressured, thermally mature, Mesozoic to Paleozoic rocks characterized by multiple, stacked, “permeability challenged” gas and oil reservoirs, characterized by little to no water production.

This Deep Basin fairway has produced >10 TCF of gas with up to 1750 TCF OGIP, and remains relatively undrilled by American standards. The initial Deep Basin reservoirs in the Elmworth-Wapiti area targeted aggradationally-stacked Lower Cretaceous high permeability shoreface conglomerates encased within lower reservoir quality “tight” sandstones, siltstones, organic shales, and coals. Until recently, these “sweetspots” of High Permeability Basin Centered Gas (HP-BCG), have been the traditional reservoir targets.

The "Deep Basin" straddles the Alberta - British Columbia border in front of the over thrust belt in the western edge a/theAlberta Sedimentary Basin, covering some 26,000 square miles (67,000 km2).

Its geology is complex: at least 18 different zones from the 15,000-ft (4600-m) section of clastic rock, ranging in age fromPermian to Upper Cretaceous. These multiple stacked gas bearing reservoir sandstones are found downdip of stratigraphically equivalent water-bearing zones. .

The "Deep Basin" consists of two basic reservoir types: conventional and tight. Conventional reservoirs consist of medium-grained sandstones to conglomerates with porosities of 8% to 12% and permeabilities in the millidarcy to darcy range. Unstimulated flows in the range of 1 million to 28 million cubic feet per day are common (28,000 m3/d to 78,000 m3/d).

The Spirit River Formation, a conventional reservoir, is a thick clastic sequence composed of a series of transgressivemarine and regressive coastal/deltaic cycles. The major hydrocarbon reservoirs are mature, pea-sized openworkconglomerates deposited on the beach face during either an initial transgressive event or a regression of a shoreline.

Tight reservoirs or low-permeability fine-grained sandstones (generally less than 100 microdarcies), have porosities In the4% to 7% range with natural flows of 100 to 750 thousand cubic feet per day (2,800 to 21,000 m3/d).