Abstract: 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.

Key words: Daqing oilfield, low-permeability reservoir, sandstone reservoir, water-drive curve