Study on the Remaining Oil of Carbonate Reservoir in Tahe Oilfield

Tahe oilfield 6-7 District is karst fractured-vuggy carbonate reservoir, whose reservoir type is specially complex. The main reservoir is mainly composed of vast karst cave, whose development is very irregular. Affected by the multi-period karstification, the reservoir often develops many sets of karst cave system, the ultimate recovery rate is significantly lower than other oilfield at home and abroad. Based on the actual development situation in 6-7 District, high quality three dimensional seismic, well log data, rock core and production data, combined reservoir engineering with numerical simulation multi-disciplinary approach, a comprehensive study is used in the remaining oil distribution in this paper. The pattern of remaining oil distribution controlled by various factors are classified into six main types, which provide the basis for prediction for distribution of remaining oil and improvement of ultimate recovery.