ABSTRACT

The discovery of oil in commercial quantities at Inga in January, 1966 has resulted in a relatively high rate of drilling activity in that part of the British Columbia fold belt. In January, 1967 the Inga Field was designated by the British Columbia Department of Mines and Petroleum Resources to include an area of 14,080 acres. Up to the middle of February, thirty wells had been drilled in and near the field to test productive sandstones in the Upper Triassic Charlie Lake Formation. Of these, nineteen have been completed as oil wells, two encountered gas, and nine were abandoned. Another five tests are currently (February, 1967) in the drilling stage.

Production is obtained from a thin quartzose sandstone, herein named the Inga Member, situated near the middle of the Charlie Lake Formation. Some oil also occurs in a newly named, slightly younger, Coplin Member. The trap is associated with Laramide fold structures which are expressed at the surface and tend to control topography in the area, but which at the level of the reservoir are modified as a result of rapid thinning of the intervening section across the area. Oil production is limited vertically on the Inga anticline and on the adjacent structure to the east by the presence of gas caps. The western edge and part of the eastern boundary of the pool is determined by the loss of porosity resulting from increasing dolomite cementation and secondary anhydrite.