Study On The Optimization Of Injection-production At High Water Cut Stage In Xianhe Fault-block Reservoirs

Xianhe Fault block oil reservoir has a very complex fault system.Its structure is crushed.There are many subzones along the vertical direction and the character difference in horizontal direction is very apparent.The permeability of most reservoirs is high.The aeolotropsim is very terrible in vertical direction.The well pattern in Xianhe has been optimized at high water cut stage.But as to Xianhe Fault block reservoir,well pattern optimization is not the best method,because the well pattern is already relatively perfect,it is necessary to implement hydrodynamic method by means of injection-production to decrease the water cut and improve the recovery ratio.The methods of injection-production optimization include periodic injection-production and liquid rate improvement.This article mainly studies the mechanism that injection-production optimization improves the recovery ratio.This article analyzes the factors that affect the reservoir recovery using numerical modeling.Then the optimization of injection-production optimization is conducted through selecting the typical block and building the numerical model of the block.Finally,the method is applied in Xianhe Field which results in the effect of water cut decreasing.Study the pressure change,the streamline change and the oil saturation change of the reservoir at the period of injection-production optimization using the technique of reservoir numerical simulation.Compared with the regular method of injection-production,the mechanism of injection-production optimization can be studied.Study the effect of injection-production optimization at different affecting factors.Compare the improving recovering ratio range at different injection-production methods.Choose the recovery ratio improving range as a standard so as to study the affecting factors of injection-production optimization.According to the mechanism of enhanced oil recovery injection-production optimization,actual model optimization was carried out.The effect of the application of history matching and optimization of injection-production optimization shows that the water cut decreases by 6.7 percent in Fault block Liang13 ES2⁹.The improvement measures are that production well stops,injection well works in water district to improve the pressure,both injection well and production well stop to collect oil and then only production works with the pressure decreasing.The liquid improving pattern of injection-production optimization at different size of oil belt is built in Fault block Liang60 ES2^6-7.The improvement measures are that take the advantage of the pressure of the reservoir,the liquid rates of the reservoir that has wide oil belt should be improved but the one that has narrow belt should not.