Optimization And Numerical Simulation Of Deep Profile Control System In Block Z

After many years of waterflooding development,block Z has entered the middle and high water cut stage.The main reservoir is flooded seriously,and the inefficient and ineffective water injection cycle is serious.Relying on conventional water injection adjustment has not achieved the desired effect.The remaining oil in block Z is scattered and locally enriched,mainly of plane interference type and interlayer interference type.According to the development degree and remaining oil distribution characteristics of the current oil field,it is urgent to study the deep profile control and drive technology in the middle and high water cut stage of low-permeability reservoir,so as to improve the development effect of block Z and improve the oil recovery.In this paper,three kinds of deep profile control and drive systems are selected for low permeability fractured reservoirs: 0.15% 15 million ordinary polymer profile control and drive system(poly ratio 15:1),0.1% 12 million salt resistant polymer profile control and drive system(poly ratio 20:1)and 0.08% 16 million salt resistant polymer profile control and drive system(poly ratio 25:1);the shear resistance,stability and injection performance of the three systems are evaluated.The experimental results show that mechanical shear can reduce the viscosity and prolong the gelation time of the deep profile control system;under the condition of 50 ?,the three systems all have good gelling stability in 60 days;after the deep profile control and drive system is injected into the core,it can continue to gel in the core,increase the flow resistance and play the role of profile control and drive.Secondly,the indoor oil displacement effect evaluation experiment is carried out for three kinds of profile control and displacement systems,the experimental results show that 0.1% 12 million salt resistant polymer flooding control system(20:1 polymer cross ratio)has the best oil displacement effect;the earlier the injection period of the profile control system is,the better the effect of EOR is;It can not only save cost,but also achieve better oil displacement effect by selecting the profile control system and polymer slug injection.Finally,the injection parameters are optimized by numerical simulation.According to the simulation results under different injection systems,0.1% 12 million salt resistant polymer flooding system(poly ratio 20:1)has the best effect.Compared with water flooding,the oil recovery can be increased by 2.81%,and the maximum water cut reduction is 6.59%.From the simulation results of different injection rates,it can be seen that with the increase of injection rate,the recovery factor increases and the increase amplitude decreases;from the simulation results of different injection timing,it can be seen that the total recovery rate increases with the advance of injection time;the best effect of EOR is two years alternate injection of profile control system and polymer,and the ratio of output to input is 2.134.