Chapter 7: Enhanced Air Injection

Most previous publications on air injection have dealt with heavy-oil applications. An increasing trend, however, is air injection for light-oil recovery (see Gutiérrez et al. 2008). The purpose of this chapter is to provide a better overview of air injection application in both heavy and light oil. An emerging area of air injection for enhanced gas recovery is also discussed briefly. Here, the term “air injection” includes conditions under which carbon-carbon bonds are oxidized to produce carbon oxides (i.e., conventional combustion reactions) and conditions in which such reactions may not occur with great frequency (e.g., some light-oil applications). A historical perspective on the theory and application of air injection processes for recovery of petroleum is offered first. Then, significant aspects of screening, scoping studies, reservoir characterization, and field applications are discussed. In particular, case histories of some successful air injection projects are presented, and the economics of air injection for two field cases (high pressure and low pressure) are discussed. The environmental aspects of air injection are discussed next. Finally, some typical example problems are presented to help the reader with the application side of the theories.