大庆油田外围低渗透砂岩油藏水驱曲线特征

Features of Water-Drive Curves of Low-Permeability Sandstone Reservoirs in Daqing Peripheral Oilfields

应用甲、乙、丙、丁等4种水驱曲线,计算了大庆外围35个低渗透区块的石油可采储量,确定了水驱曲线直线段出现时对应的含水率,平均为20.8%,远低于高渗透油藏。在应用水驱曲线计算的外围低渗透油藏可采储量中,丙型水驱曲线计算的可采储量最高,其次分别为乙型、甲型和丁型;上述结论也在国内其他低渗透油藏应用中得到了验证。

Type-A,-B,-C and-D water-drive curves are applied to calculation of the recoverable reserves of 35 low-permeability blocks in Daqing peripheral oilfields,and the corresponding water cuts when the straight line segments of water-drive curves appeared have been ascertained.The application results indicate that the recoverable reserve calculated by Type-C curves is the highest among the four types,and then Type-B,Type-A and Type-D in turn,which are different with those of middle-and high-permeability reservoirs.For the peripheral low-permeability reservoirs,the straight-line-segment water cuts when the water drive curve appeared are about 20.8% in average,much lower than those for high-permeability reservoirs.Such a last understanding has also been verified by other low-permeability oilfields in China.