GAS-STORAGE RESERVOIR PERFORMANCE OPTIMIZATION THROUGH THE APPLICATION OF DRAINAGE AND IMBIBITION RELATIVE PERMEABILITY DATA

Gas storage reservoirs are utilized in many locations to seasonally st ore gas in summer months for periods of high demand in the winter. Thi s generally involves the cyclic pressurization and depressurization of the reservoir on an annual basis. If the storage reservoir overlies a n aquifer or residual oil leg, this may involve the cyclic motion of t he gas-liquid contact and gas zone. This paper documents an extensive series of reservoir condition relative permeability experiments conduc ted on core material from a gas storage reservoir in southern Ontario to investigate the effects of cyclical pressurization and depressuriza tion on reservoir performance. The tests illustrate how the cycling of applied net overburden pressure and the presence of trapped gas and w ater saturations in the dynamic gas-liquid transition zone can affect the production and injection of gas in the storage reservoir. Applicat ions of the data, and extensions to field performance are also present ed.