特高含水期水驱砂岩油田井网部署自动优化方法

注水油田开发设计的重要环节是井网设计,在布井时应充分考虑储层的非均质性与各向异性以及注入水在地下的驱替动态,布置与其相匹配的井网,即矢量井网。油田是一个复杂的系统,井网调整时井组间相互制约,为了确定最优的井网部署方案,基于数学建模和最优化理论,建立了井网部署优化模型,以各注采连线上见水时间相同作为目标函数,辅以适当的约束条件,优化各井的位置。井网部署优化模型属于大规模、多变量的复杂优化问题,采用遗传算法进行求解,速度快、效率高。文中推导并建立了考虑非均质和各向异性非活塞式驱替见水时间计算方法,相比传统的通过耦合数值模拟程序求解开发指标方法,效率更高;建立了包含25口井的概念模型,验证了该方法的有效性,优化后可实现井网与储层非均质与各向异性的最大匹配。

Optimization of well arrangement in ultra-high water-cut water-flooding sand reservoirs

The design of the well pattern is one of the most important tasks in water-flooding reservoir development.The heterogeneity and anisotropy of the reservoir and the displacement dynamics should be considered carefully in the well arrangement to make sure the reservoir match with the well placement,i.e.,the vectorial well arrangement.A reservoir is a complex system,and a well location modification in a well group will lead to a modification in its neighbor group in well placement adjustment.In order to determine the optimal well locations,a well placement optimization model was established based on mathematical modeling and numerical optimization theory.The objective of the model is to equalize the breakthrough time of the injected water along each injector-producer pair.With a series of constraints,the locations of all wells are optimized.Since the well placement optimization model is a large-scale,multi-variable complex optimization task,the genetic algorithm is selected to solve this problem,which is fast and effective.Considering the heterogeneity and anisotropy of the reservoir and the non-piston displacement effect,an analytic method of calculating injection water breakthrough time is given.The objective evaluation by this method is faster than numerical simulation.An example including 25 wells was used to verify the validity and accuracy of our method.Results show that the optimal well arrangement plan fits the reservoir heterogeneity and anisotropy well and can obtain better performance in reservoir development.