Numerical modelling of forward in-situ combustion process in heavy oil reservoirs

In-situ combustion (ISC) is an enhanced oil recovery method used to increase heavy oil recoveries. The present work describes the development of a predictive numerical model considering coupled thermal and fluid flow characteristics encountered during the complex ISC process. The physical model considers dynamic multi-phase fluid flow of oil, water and gas, and involves simultaneous heat and mass transfer mechanisms, while the kinetic model considers oxidation and cracking reactions resulting in generation of heat energy. The model considers capillary pressure effect and heat losses into the surroundings. The resulting coupled non-linear conservation equations have been solved iteratively using finite difference based numerical tool. The developed numerical model has been history matched with the results reported by Crookston et al., (1979) and found to be in good agreement. Sensitivity analysis on oxygen injection and kinetics of cracking reaction projected a dominant affect on the thermal and oil recovery profiles. [Received: August 4, 2015; Accepted: February 29, 2016]