IN-SITU COMBUSTION IN HEAVY-OIL RESERVOIRS - PROBLEMS AND PERSPECTIVES

In-situ combustion is an enhanced recovery technique offering many adv antages over other enhanced recovery processes in heavy-oil reservoirs , such as a more efficient overall drive mechanism, less energy consum ption, and less total environmental impact. Although this process has been extensively studied in both the laboratory and the field, it has failed to achieve general acceptance because of the small number of su ccessful field applications. Many of the failures resulted from inappr opriate applications of the fireflooding process, which, in turn, aros e from misconceptions about the way in-situ combustion works. This pap er will discuss recent advances in the authors' understanding of combu stion kinetics, examine some of the mechanisms that led to the failure of several Canadian heavy-oil projects, and offer suggestions on how the correct oxidation mode can be encouraged in a fireflood operation. Several promising field strategies, including the use of horizontal p roduction wells, will also be presented.