Methods to Enhance Success of Field Application of In-Situ Combustion for Heavy Oil Recovery

While much has been learned in the laboratory over the past four decades about the in-situ combustion (ISC) process, especially through carefully conducted physical model experiments, and many advancements in numerical simulation capability have been achieved, successful field application of ISC remains a rarity. This paper discusses challenges that have been faced in moving from laboratory to field and some strategies that may be used for improving the success rate. There is a brief discussion of the advantages and disadvantages of ISC as a recovery method and comparisons with steam injection, which is the dominant thermal recovery method used in the field. A discussion of the challenges and progress made in numerical simulation is provided with the suggestion that such mathematical modeling can now be a useful tool in designing field projects and can increase the probability of success. The needs of industry to operate safe, simple, and economically and environmentally sustainable projects are discussed along with the currently negative perception of the ISC process in industry. The paper makes some suggestions regarding how to address these issues. The main thesis of this paper is that air injection into a reservoir introduces a large amount of nitrogen that is detrimental to the displacement of oil, and oil recovery yet offers few, if any, advantages. Reducing the amount of noncondensable gas (NCG) associated with the process can be done mainly in two ways—by using oxygen-enriched air injection and furthermore by injecting a mixture of steam and oxygen-enriched air. The paper does not make a comprehensive review of past field projects but does include a summary of promising areas for future application of the ISC combustion recovery process.