水驱油田采收率与注入孔隙体积的定量关系

采收率是评价油田开发效果的重要标准。通过对胜利油区不同油田多块岩心驱替试验结果的分析,发现采收率ER与注入孔隙体积倍数nPV存在定量关系,从丙型水驱曲线出发结合注采关系和驱替试验数据得出E_R-n_PV关系式,并分析E_R-n_PV关系式中系数的物理意义。对岩心驱替试验与现场生产数据回归曲线以及孤岛试验区聚合物驱前后E_R-n_PV回归曲线进行对比分析。结果表明储层低含水阶段水驱采收率明显低于岩心试验的水驱采收率,而在中后期差距逐渐减小,计算值与实际生产数据吻合度高;注聚开发可有效地提高采收率,且注聚开发前计算的波及体积大于实际波及体积,证明聚合物驱有效提高了波及体积;E_R-n_PV关系式能应用于水驱油田采收率预测,并对提高采收率措施效果进行评价。

Quantitative characterization of oil recovery and pore volume of water injected in water flooding

Oil recovery efficiency is a critical standard to evaluate the effectiveness of oilfield development techniques.Through the analysis of the results of various core flooding experiments in Shengli Oilfield,it was found that the oil recovery(ER)has a good correlation with the times of pore volume of water injected(nPV).Based on the C-type water flooding curve and combining the injection-production relationship with the experimental data,an E_R-n_PV relationship equation was derived,and the physical implication of the correlation coefficients was analyzed.By comparing the core flooding testing with the regression curves of the real field production data,it was found that the recovery rate in water flooding in the low-water-cut stage of the reservoir is obviously lower than that in the core flooding experiments,and the difference is gradually reduced in the middle and late stages.For polymer flooding,by comparing the E_R-n_PV regression curves before and after polymer flooding in a field pilot testing in Gudao,it was found that the polymer flooding can effectively improve the recovery rate,and the predicted sweeping volume is larger than the swept volume actually achieved,which proves that polymer flooding can effectively increase the sweeping volume.Therefore,the E_R-n_PV relationship can be used to predict oil recovery and evaluate the efficiency of the enhanced oil recovery measures.