Abstract: The Jurassic Sangonghe reservoir in Mobei-2 W ellblock is a typical gas-cap pool where the gas cap volume is 0.91 times as big as itsoil ring's. With the application of reservoir numerical simulation method, the rational development process for gas-cap pool is studied. The sim-ulation and design of various processes such as depletion drive, waterflooding, injection-withdrawal ratio and gas-cap production, etc., are per-formed,based on modified geological model by production history matching of Sangonghe reservoir. The simulated results show that it is themost favorable to adopt waterflooding process that two rows of injection wells are arranged respectively in inner part of oil-water contact and out-er part of oil-gas contact, and keep injection-withdrawal ratio of 1.0; simultaneously, an equilibrium gas well to be drilled on the gas cap for oilring development is available to obtain higher recovery percent of reserves.

Key words: Junggar basin, Gas-cap reservoir, numerical simulation, water flooding, recovery percent