A Guide to High Pressure Air Injection (HPAI) Based Oil Recovery

Abstract In recent years, high pressure air injection (HPAI) has proven to be a valuable IOR process, especially in deep, high pressure, low permeability fields where other recovery processes are uneconomic. This paper will provide engineers and engineering managers with a wide-ranging look at the key factors that should be addressed when considering a high pressure air injection (HPAI) based IOR process in a light oil reservoir. The paper is based on many years of involvement of the authors both in the laboratory and the field, as well as drawing on published literature. The main focus is on key design and operating criteria that must be considered, including reservoir screening, air injection design, ignition, and monitoring. The benefits and potential risks of HPAI are also discussed. Along with the discussion of design and operating criteria, the paper contributes significantly in the comparison of oxidation/combustion kinetics for light oils versus heavy oils (HPAI versus in situ combustion), as well as in a discussion of the oil mobilizing effects of a gas flood compared to an advancing thermal (combustion) front.