低渗透油藏注水开发的水突进特征

用活塞式水驱油方法，研究具有启动压力梯度的油藏中油水两相径向渗流特征，包括单一油层的驱替特征和双层油层在水驱过程中油水界面突进的差异。分析表明：相同注采压差条件下，启动压力梯度越大，生产阻力越大，油水界面推进越慢，产液量越低。增大注采压差．可以增加油井的产液量，减弱启动压力梯度对生产的不利影响。启动压力梯度加剧了双层油层注水开发时的层间矛盾．特别是在低渗透层渗透率小于50mD时影响更为显著。

Water fingering feature in low permeability reservoirs

By using the method of piston drive, the water-oil flow performances are studied in low permeability reservoir with threshold pressure gradient, including the drive performance in single zone and the water-oil interface fingering feature in double zone, suggesting that under same injector producer pressure difference, the higher threshold pressure gradient results in higher yield resistance, slower interface movement and lower production rate. The increase of injector producer pressure difference will increase the fluid yield of the producer and decrease the unfavorable effects of the threshold pressure gradient. The threshold pressure gradient increases the interlayer interference, especially when the lower permeability of the two zones is less than 50mD.