Abstract
Laboratory experiments on the reverse combustion were carried out to investigate the fundamental phenomena in a reservoir and the influence of reservoir conditions on the overall behavior of fireflooding, with the aim of the application for improving oil recovery. Results are summarized as follows.
(1) Since cork formed by the thermal decomposition is the fuel in a forward combustion, the forward fireflooding would not be applicable unless oil density is high enough. However, there is no limitation of oil density in the reverse combustion, because light components, perhaps in a gas phase, burn as fuel.
(2) The heat transfer to a low temperature region ahead of the combustion front and the heat generation by the combustion are competitive mechanisms for controlling the temperature of the combustion zone. Therefore, the heat transfer coefficient of the reservoir ahead of the combustion front is one of the most important factors affecting the whole behavior in the reservoir.
(3) Oil recovery through the reverse combustion experiments at the present study was 40 to 60%, whereas that of the forward combustion experiments at previous studies was ca. 90%. It was decreased as the oil density and/or the reservoir pressure increased.
