Investigation of Fractures Geometrical Properties on Conventional Fire Flooding (CFF) Process Performance

The Conventional Fire Flooding (CFF) has been studied deeply in conventional reservoirs as a promising<br>EOR method for certain non-fractured sandstones; however, its application feasibility in fractured<br>carbonates remained questionable. The aim of the present work was to evaluate the effect of fractures<br>geometrical properties such as orientation, density, location and networking on the CFF process<br>performance. Combustion parameters of a fractured low permeable carbonate heavy oil reservoir in Iran<br>called Kuh-E-Mond; applied to simulation study. Simulator has been validated with KEM combustion tube<br>experimental data. Validated model modified to study CFF in a 3D semi-scaled combustion cells. Oil<br>recovery was slower in the case of fractured models compare to the conventional one since in the former<br>the governing mechanism is oxygen diffusion from matrix into fissure and vice versa which will be<br>prolonged. This prevailing mechanism reduced rate of oil recovery in the presence of either traversal or<br>longitudinal fractures. Ultimate oil recovery was higher in the case of near injector traversal fissures<br>compare to near producer ones. CFF performance was lower in the case of near injector longitudinal<br>fractures compare to the farther ones. Contrary far injector longitudinal fissures improved the areal sweep<br>efficiency of oxygen at the lateral side of the combustion cell and hinder the cone liked shape of air profile<br>in conventional model. Higher traversal fracture density reduced oil recovery due to consequent matrixfractures<br>diffusion compare to improved recovery performance in the case of higher traversal fracture<br>density. In the case of networked fractures longitudinal fissures enhanced the performance of traversal<br>fractures and higher ultimate oil recovery compare to the case of either traversal or longitudinal fissures<br>obtained which confirmed that CFF is more feasible in the case of densely fractured reservoirs such as<br>those in the Middle East.