Investigation of Fractures Geometrical Properties Effect on the Efficiency of Top-Down In-Situ Combustion Process in Fractured Carbonate Systems

The top down In-Situ Combustion (ISC), involves the stable propagation of combustion front from top vertical injector to the bottom horizontal producer. Besides laboratory studies in conventional sandstones, no application of the process in fractured carbonates has been addressed yet. In this paper a successful combustion tube history match of Iranian low permeable heavy oil reservoir called ″Kuh-E-Mond″, is presented and accompanied with details of experimental and simulation models. Validated model has been modified further to investigate the feasibility of ISC in fractured carbonate reservoirs mimicking block scale combustion cells. Effects of fractures geometrical properties such as orientation, location, extension, density, spacing and dispersion have been considered. Results confirmed higher outcome in the case of optimum vertical or horizontalfractures density and spacing. Far injector vertical fractures enhanced the process in terms of ultimate oil recovery and sweep efficiency. Longer vertical fractures and higher their dispersion through the reservoir improved the recoveries compare to the lower efficiency in the case of extended horizontal fractures and higher their dispersion through reservoir. Simulation analysis confirmed that Top-down In-Situ Combustion has higher feasibility in the case of highly networked fractures through the reservoir such as those occur in the Persian Gulf coast.

Keywords:

In-Situ Combustion , fractured carbonate reservoirs , heavy oil recovery , simulation analysis