In-situ combustion projects in heavy oil reservoirs were started early part of the last century. The number of projects was increasing toward 1960s. More than 120 projects were carried out in U.S. at that time. After 1970s, it plunged to less than one-tenth. But in the middle of 90s, it began to increase again. The main reason for this rise was an increase in-situ combustion projects in light oil reservoirs and recently they have been increasing.
Since 1999, our study of the light oil reservoir from the Minami-Aga oil field in Japan has continued. Now we focus our attention on minimum air flux which is needed to sustain a combustion front. The minimum air flux will be used to design an air compressor for a pilot-project.
A discussion of minimum air flux for heavy oils was published by Nelson and McNeil5 . It is believed that a mechanism of combustion for the light oil is different from the heavy oil. It is also believed that the light oil's combustion front is less stable than the heavy oil's. Therefore in our case to estimate the minimum air flux, it might be better to take a different way. In this paper, a thermal simulator was used to estimate the minimum air flux. Prior to a simulation study some High Pressure Ramped Temperature Oxidation (HP-RTO) tests with our oil were carried out to obtain combustion parameter. A reaction model in the thermal simulator was obtained based on the HP-RTO tests results.