Philosophy and Technology of In-Situ Combustion in Light Oil Reservoirs

The basic in-situ combustion technology is reviewed with emphasis on light oil reservoirs. The stoichiometry and the propagation of the combustion zone through the porous rock of a reservoir are discussed in fundamental terms. The most distinguishing fact of in-situ combustion is air consumption, which is related directly to fuel consumption. In evaluating a prospect for combustion, a knowledge of the geologic characteristics of the reservoir is vital to the understanding of performance and diagnosis of operation problems. Fuel content is another most important variable. It is important to sample the different lithologies of a given column in order to arrive at an average fuel content for the reservoir. The Fry In-Situ Combustion Test is cited as an example of the application of these principles to light oil reservoirs. The selection of a reservoir for conducting a successful in-situ combustion operation requires much greater geologic understanding and engineering skill and competence than is necessary in applying the older methods of secondary recovery. (16 refs.)