Waterflood Using a Muskeg Water Source - Milligan Creek Unit, B.C.

Abstract

Abstract The Milligan Creek field, in northeastern British Columbia, is a small but high-capacity sand reservoir of Triassic age. Waterflooding was initiated early in the life of the reservoir to provide pressure maintenance and increase oil recovery from the pool. Due to the lack of a subsurface supply in the area, muskeg water from a nearby creek was utilized. This cold water, with its high content of iron and organic material, has proved to be a major water treatment problem. After considerable experimentation, a process using flocculation, filtration through a sand-anthracite filter and deaeration was found to yield water satisfactory for injection, although a seasonal variation in water quality remains a problem. Four years of waterflooding have yielded satisfactory results, with a decrease in voidage, an increase in reservoir pressure and the attainment of a high level of production for a pool of this size. Performance has been accurately predicted by means of a potentiometric model, which has proved to be a useful tool in guiding the progress of pool operation. Recovery to date of 15 per cent of the original oil in place is approaching what was expected under primary solution gas drive, and this should more than double under waterflood.