Air Injection into oil reservoirs specially offers unique technical and economic opportunities for secondary and/or tertiary oil recovery in light oil reservoirs with low permeability, in which conventional water injection techniques have been unsuccessful and/or uneconomical. This paper provides a comprehensive overview on the oxidation reactions and improved oil recovery (IOR) processes of air injection into low permeability light oil reservoir based on detailed analysis of some field projects and reservoir simulation case study carried out on a largely dipping, low permeability light oil reservoir, the Q131 oil block located in Eastern China to analyze the characteristics and processes of air injection.
Kinetic models of low temperature oxidation (LTO) reactions were designed and used in the reservoir simulation study to predict oxygen consumption in the reservoir, examine the reaction schemes, IOR mechanisms, and the thermal effect of oxidation reactions occurring during the air injection process. The results of the study including temperature effects, oxygen concentration, oil saturation, gas breakthrough, GOR, and cumulative oil produced were outlined and discussed in details. An average of increased oil recovery factor of more than 45% OOIP was achieved when using a maximum of 60000m3/day air injection rate and no oxygen breakthrough was observed at the production wells.