ABSTRACT

In northeastern British Columbia, the Mississippian carbonate-shale sequence consists, in descending order, of the Debolt, Shunda, Pekisko and Banff Formations. The Debolt is here divided into five members: upper carbonate, upper argillaceous, middle carbonate, lower argillaceous and lower carbonate. Many normal and reverse faults are present.

Oil and gas fields occur where folds and faults cross areas of dolomite development. Dolomite is found most commonly at the base of the upper carbonate and this is the main objective in most of the area. These beds are here named the Pink Mountain Dolomite Beds. In the Prophet River area, thick dolomites are present in the middle and lower carbonate members. The middle carbonate dolomites are here called the Trutch Dolomite Beds.

Many of the wells drilled to the Mississippian were abandoned before reaching the Pink Mountain Dolomite. In addition, parts of the area with good Debolt reservoir potential have not been drilled.

Porous echinoderm shoals, similar to those cropping out in the Shunda and lower Debolt Formations in the Rocky Mountains near Monkman Pass, may be present in the subsurface. These shoals also could provide important traps.