Nineteen gas fields and one oil and gas field had been discovered in the Rocky Mountains Foothills of Alberta to the end of 1965. The Alberta Oil and Gas Conservation Board estimated remaining reserves of marketable gas at 4,878 billion cu ft, gas liquids at 116.2 million bbls, and sulfur at 32.685 million long tons.

Mississippian strata constitute the principal reservoir rock; Triassic strata are important in two fields; Devonian strata provide the reservoir in one field, and are of minor importance in another. The gas fields of the Foothills are in overthrust fault structures, overthrust from the west and striking parallel with the Mountains. Closure is afforded by the thrust fault on the east, the steeply dipping west flank, and the north and south plunges of the fault blocks. Subsurface structures generally are reflected at the surface by folds or imbricate fault zones, but seismic surveys normally are required to confirm dislocation in Paleozoic rocks, and to determine depths and configuration.