Air Injection in Heavy Oil Reservoirs - A Process Whose Time Has Come (Again)

Abstract

Abstract Air injection in heavy oil and bitumen reservoirs, also known as in-situ combustion or fireflooding, is an enhanced recovery process that has been around for several decades. While on paper or in the laboratory this oil recovery process shows tremendous potential, its success in past field applications has been spotty at best. Times have changed, and so has our understanding of air injection-based oil recovery processes. Our available technologies for accessing and producing the reservoir and our emphasis on reducing environmental impacts have changed as well. In short, the industry is smarter, has better technology, and maintains a significant commitment to sustainable resource development. This paper reviews portions of the past history of air injection in Canadian heavy oil and bitumen reservoirs; discusses the significant advances in our understanding of the in-situ process; reviews currently successful air-injection projects; summarizes the keys to successful implementation of air-injection-based recovery processes; and proposes several novel applications of air injection, including hybrid processes with steam or vapour solvent, in-situ upgrading, in-situ steam generation, and in-situ gasification. Introduction Since its accidental discovery in the early 1900s, the use of air injection as an enhanced oil recovery process has experienced a somewhat checkered history. In the 1950s and 1960s, it was actively and successfully advanced as a thermal process for heavy oils in California. Many of those projects have been summarized by Chu(1) and Sarathi(2). The successes in California brought in-situ combustion or fireflooding to Canadian heavy oils and bitumens in the 1960s to 1980s. While there were some successes in these pilots and projects, there were many more failures, and air injection in heavy oils never seemed to reach its theoretical potential. In the two decades that have elapsed since then, significant research efforts have been made to understand both the causes of failures and successes in past in-situ combustion projects. At the same time, the heavy oil industry has evolved significantly.