Study On Residual Oil Distribution After Water And Polymer Flooding For High Water Cut Field And The Method Of Improving Oil Recovery

Along with the development of continental reservoirs dried up,the domestic and even world oilfield entered middle and later periods of the development.Gradually,many oil companies'development began to focus on the deep water area.Although the yield of offshore oil is high,the development has the characteristics of high risk and high investment in the sea.Therefore,polymer flooding began to be used in offshore oil field,and obtain good production effect.But as the polymer flooding,the oil field water cut also began to rise,affecting the oilfield development effect.So the study on the remaining oil distribution after polymer flooding and the methods of improving oil recovery for high water cut period is of great significance to increase production in offshore oil field.In this paper,firstly,based on the polymer flooding results of core displacement tests,the history of parameters of polymer experiment were matched.The parameters of history matching include polymer viscosity,shear rate,inaccessible pore volume and residual resistance coefficient.The results show that the accuracy matching of is high,so it is effective to characterize the parameters of Jinzhou 9-3 oilfield polymer flooding polymer and ensure the effectiveness of the polymer flooding history matching later.Based on the actual field data of Jinzhou 9-3 oilfield,reservoir numerical simulation model is established.By means of history matching of Jinzhou 9-3 oilfield reserves and production performance,the results show that model precision is high and model accuracy meets the requirements.All of these provide a basis for the study of the remaining oil distribution.Based on the results of history matching of Jinzhou 9-3,oilfield remaining oil distribution are studied.It can be seen from the results that there are still large residual oil distribution of remaining for tapping the potential in Jinzhou 9-3 oilfield.Through the analysis of the causes of residual oil distribution,and put forward 3 residual oil distribution modes,including imperfect pattern of remaining oil distribution patterns,the remaining oil distribution patterns under the influence of the structure and the remaining oil distribution patterns under the influence of the heterogeneity.On the basis of the residual oil distribution,and through the analysis of W platform polymer flooding production dynamic data,the reasons of bad polymer flooding development effect is obtained.And a method to enhance oil recovery is proposed.Through the mechanism model,the pattern form is changed,and compared with the effects of polymer flooding,polymer flooding after water flooding,polymer and surfactant flooding and gel flooding,it is recommended that polymer and surfactant flooding as a method to improve recovery efficiency of development.According to the result of mechanism model simulation,t,it is concluded that the method can increase oil of 157000 m~3 and improve the recovery rate of 10.26%by simulation of W platform development.