Experimental Investigation On CO₂ Huff-puff In Gas Injection Expand Pilot Area Of Fang48

Low permeability reservoir has such features as high viscosity, the low starting pressure, the poor water intake ability, and the low displacement efficiency. fang 48 block has these features,is the low permeability reservoir. In order to develop the reservoir reasonably and effectively, the paper carries on the feasibility of CO2 huff-puff on the basis of the sufficient survey about low permeability features and the low permeability condition at home and abroad when injecting gas.CO2 huff-puff technology is an effective way that can enhance oil recovery . In this paper, we introduce fang 48 blocks of ultra-low permeability reservoir CO2 huff-puff experiment. The results show that: CO2 will help to reduce the residual oil saturation to make it easier for oil to be produced, and improved oil recovery strata. Through CO2 huff-puff experiment, a series of parameters such as recovery efficiency,oil/gas exchange ratio,and gas-oil ratio are obtained under various kinds of pressure.In the huff and puff process, the gas injection pressure to take 25MPa, the producting pressure is 7MPa, first the jet, after the huff and puff, Gradually step-down in jet phase can get a better result. from the closed time, 12d of the best. Throughput cycle not more than four cycles. In this way, can improve the efficiency of displacement, but also save a lot of gas, reduce production costs.