Optimization Of Injection Parameters For Polymer Flooding Adjustment In Well C Pu I1~2 Classified Wells

After nearly 50 years of water flooding,the polymer flooding began in February 2020 in the C well block.Now,it has entered the water-cut decline stage of polymer flooding.The whole well area is mined by a set of polymer flooding schemes.Due to the large difference in the plane of the well block,it is affected by the development of the oil layer and the internal connection,and the overall adaptability is poor.It is urgent to research the optimization and adjustment scheme of different regions of polymer flooding injection parameters in Pu I1～2layer of C well area.In this paper,based on the problem that the adaptability of different regions of C well area to the polymer flooding scheme is quite different,the numerical simulation method is used to optimize the polymer flooding adjustment scheme.Firstly,the geological model under the condition of facies control is established by using logging data,and then the history matching of the water flooding stage and polymer flooding stage is carried out by using numerical simulation software.On the basis that the fitting indexes meet the accuracy requirements,the distribution of remaining oil in Pu I1～2 layer and the prediction of remaining oil reserves are studied.Combined with the physical parameters and development performance of the block,the injection-production wells are divided into three different well groups A,B,and C with the injection wells as the center.Among them,the class A well group has the best connectivity and the strongest injection-production capacity,but it has poor adaptability to the polymer flooding scheme.The reservoir of class B well group has good connectivity and injection-production capacity,and the reservoir of well group has good utilization and adaptability to polymer flooding scheme.The development of type C well group is the worst,and the adaptability to polymer flooding scheme is also the worst.The polymer flooding adjustment scheme is designed for different well groups,the injection parameters are optimized and the development effect is predicted.Through numerical simulation research,the reasonable injection parameters of polymer flooding adjustment in three types of well groups are determined as follows the injection rate of type A well group is 0.20PV/a,the reasonable concentration combination of three slugs is 1800mg/L,1500mg/L and 1200mg/L,and the reasonable polymer dosage is250mg/L PV,200mg/L PV and 150mg/L PV;the injection rate of class B well group is0.24PV/a,the reasonable concentration combination of three slugs is 1500mg/L,1300mg/L and 1100mg/L,and the reasonable polymer dosage is 200mg/L PV,200mg/L PV and100mg/L PV.The injection rate of class C well group is 0.28PV/a,the reasonable concentration combination of three slugs is 900mg/L,750mg/L and 600mg/L,and the reasonable polymer dosage is 100mg/L PV,100mg/L PV and 100mg/L PV.The development effect of the final combination optimization scheme is predicted.The recovery rate of polymer flooding is 56.56%,which is 10.67%higher than that of conventional water flooding,and the cumulative oil increase is 3.78×10~4t,compared with the basic scheme of polymer flooding,the recovery rate is increased by 2.81%,and the cumulative oil increase is1.00×10~4t.This study provides a theoretical basis for the adjustment of polymer flooding in different types of well groups in Pu I1～2 layer and provides technical support for the industrialization of polymer flooding in Pu I1～2 layer.