THE PILOT TEST OF ENRICHED-GAS MISCIBLE FLOODING IN CERTAIN OIL FIELD OF ALGERIA

By considering the reservoir quality and property of crude oil in certain oilfield of Algeria,we choose the representative well group to develop the Enriched-Gas miscible flooding systematically.Based on the laboratory experiment results,this reservoir is suitable to implement the miscible flooding.The slim tube experiment indicates that under the reservoir condition(83.9℃ and 10.2MPa),the MMC of LPG and nature gas is 37.1∶62.9.The results show that the MMC is capable of forming miscible fluid with the formation oil;the long core displacement experiment shows that after the water cut reaches 98%,the miscible flooding is able to enhance the oil recovery more than 15%.By numerical simulation,we analyze the sensitivity of a series of injection parameters including the injection rate,volume,mode and layers.The recommendation scheme is alternative injection in EOR-1 well group and continuous injection in EOR-2 well group,the injection ratio is 600m3/d(under the reservoir condition) and the injection volume is 0.3 PV.The simulation result of recommendation scheme can enhance oil recovery about 14%~15%.The result of pilot test reveals taht there is override phenomenon in EOR-1,the efficiency of miscible flooding is poor,and a kind of treatment is proposed to kill gas breakthrough;while the efficiency of miscible flooding in EOR-2 is very good and inspiring.