Numerical simulation of air injection processes in high pressure light & medium oil reservoirs

Abstract

A bstractResearch, pilot scale and field developments of In-Situ Combustion (ISC) for enhanced oilrecovery (EOR) in shallow, low pressure, heavy oil reservoirs intensified between the first and the secondoil crisis from 1973 to 1981. A decline of interest in EOR followed the collapse of the oil prices in 1986.Renewed interest on in-situ combustion EOR research in the late 1980’s and beginning of the 1990’s wasexpanded and focused on high pressure medium and light oil reservoirs.The applicability of air injection in deep high pressure light petroleum reservoirs wasestablished by research work of Greaves et al. in 1987 & 1988, Yannimaras et al. in 1991 and Ramey et a lin 1992. Accelerating rate calorimeter (ARC) tests were used to screen the applicability of various typesof light oil reservoirs for in-situ combustion EOR by Yannimaras and Tiffin in 1994. The most successfullight oil air injection project in the 1990s in the Medicine Pole Hills Unit, Williston Basin, N. Dakota startedin 1987 and was reported by Kumar, Fassihi & Yannimaras, in 1994. Low temperature oxidation of lightNorth Sea petroleum was studied at the University of Bath.A high-pressure combustion tube laboratory system was built at Bath University toevaluate performance of medium and light petroleum in-situ combustion processes. Gravity effects andthe impact of horizontal wells in Forced Flow In-Situ Combustion Drainage Assisted by Gravity(FFISCDAG) were studied with three-dimensional combustion experiments.In this study, the university of Bath combustion tube experiments have been simulated andhistory matched. The tube experiments were up-scaled and field simulation studies were performed. Ageneric PVT characterization scheme based on 5 hydrocarbon pseudo-components was used, which wasvalidated for light Australian and medium ‘Clair’ oil. A generic chemical reaction characterization schemewas used, which was validated for light Australian and medium ‘Clair’ oil. Advanced PVT and chemicalreaction characterizations have been recommended for future work with more powerful hardwareplatforms. Extensive front track and flame extinction studies were performed to evaluate the performanceof currently available non-iso-thermal simulators and to appraise their necessity in air injection processes.Comparative ISC field scale numerical simulation studies of Clair medium oil and light Australian petroleumwere based on up-scaled combustion tube experimental results. These studies showed higher thanexpected hydrocarbon recovery in alternative EOR processes for both pre and post water floodimplementation of ISC. Further in this study field scale numerical simulation studies revealed highincremental hydrocarbon recovery was possible by gravity assisted forced flow.The applicability of light oil ISC to gas condensate and sour petroleum reservoirs has beenexamined in this study with promising results. Light petroleum ISC implemented by a modified water floodincluding oxidants such as H2O2 and NH4NO3 are expected to widen the applicability of ISC processes inmedium and light petroleum reservoirs, especially water flooded North Sea reservoirs.

Date of Award	2000
Original language	English
Awarding Institution	University of Bath
Supervisor	Malcolm Greaves (Supervisor)