Abstract

Of the more than 20 billion barrels (exclusive of crude oil in the McMurray formation [Lower Cretaceous]) of original in-place crude oil discovered in western Canada to date, it is expected that only about 4.75 billion barrels will be produced by primary methods and water flooding. Secondary recovery methods such as in situ combustion and miscible-phase flooding could-result in the production of, approximately, an additional 8 billion barrels (exclusive of crude oil in the McMurray formation), and reviews of the pertinent factors concerning the technological application of both methods are presented. The comparatively simple regional variations in structure and thickness of the sediments in the western Canada sedimentary basin are noted, as well as the recent demonstration of parallel regional variations in the physical and chemical attributes of the formation fluids. Accordingly, each of 15 time-rock units is considered from the point of view of its areal distribution, the regional variations in thickness, stratigraphy, lithology, facies changes, and depth and characteristics of the petroliferous zones, and the regional variations in A.P.I. gravities of the crude oils. The regional applicability of the 2 secondary methods is then considered. In general, it appeared that thermal methods were most suited to crude oils in the subcrop and Sweetgrass arch regions of the Upper Devonian, Mississippian, and lowermost Cretaceous sediments. For Jurassic crude oils, thermal methods appeared suitable throughout western Canada. A reverse combustion method was considered most applicable to the crude oil in the McMurray formation. Conventional dispersed gas drives and enriched gas drives appeared to be suitable in most other regions for the other time-rock units, with high-pressure improved gas drives limited to those petroliferous zones deeper than about 5,000 ft. The miscible-slug technique appeared ideally applicable only to the Cardium formation [Cretaceous] crude oils.

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