Visual simulation experiment on the borehole with liquid production by controlling the gas in the reservoirs stimulated by top gas injection based gravity drive

In the oil reservoirs which are stimulated by the top gas injection based gravity drive, the oil-gas contact moves downward with the continuous cyclic gas injection, which inevitably results in borehole gas channeling in the early and middle stages of the production. To solve this problem, the uplift idea of " gas-liquid separation, and liquid production by controlling gas” by means of casing gas releasing was proposed in this paper. In order to figure out the movement laws and flow regimes of produced gas in the borehole and the effects of the gas on the pump in the process of uplift, the casing gas releasing was adopted to judge whether stable gas-liquid contact could be formed in the borehole, and visual borehole simulation experiment was carried out. It is indicated that stable production can be kept for a while if the casing gas releasing is at a constant rate and the tubing shoe is always located below the producing pay. The research results can be used as the guidance for the production of oil reservoirs by the top gas injection based gravity drive.