Simulation Study of the Effect of Various Water Alternating Gas Injection Schemes on Recovery in a Gas Condensate Reservoir

Abstract

Abstract The volatile characteristics of gas condensate reservoirs in the phase envelope makes its temperature and pressure conditions between the critical and cricondentherm points very sensitive to perhaps only rely on one source of reservoir energy enhancement and puts enormous technical constraints on quality decision making on effective reservoir management. Non adequate oil production simulation performance interpretation for high, base and low case scenarios based on critical high quality input data is definitely the technical missing link which severely hampers effective design, development, planning, optimization and prediction of gas condensate reservoir performance. The aim of this study was to evaluate the recovery performance of a rapidly declining reservoir flow rates of a gas condensate reservoir through the water alternating gas (WAG) injection technique using the Schlumberger Eclipse simulator. Five different case scenarios were used which include cases of no-injection wells (which is the control case), gas injection, water injection, water alternating gas (for 7, 5, and 3-spot patterns) and flow rate alterations with a seven spot pattern-WAG technique. A total of 13 simulation runs were done with one control and 12 other runs with high, base and low cases. The sensitized water and gas injection rates used ranges from 12,000STB/day to 2,000STB/day and 12,000MSCF/day to 1,000MSCF/day. All results showed increase in oil flow rates with appreciable pressure response and subsequently, the viable option would be to consider in the short term water and gas injection before considering the more holistic WAG techniques in the long term. This is due to the current economic and technical constraints to boost the viability of the best choice of action. The results of these comprehensive simulation runs is a viable data bank needed for critical decision making for improved recovery from this rapidly declining condensate reservoir.