基于变阶长迭代动态规划的聚合物驱方案动态优化

聚合物驱是一种重要的提高原油采收率技术. 针对聚合物驱的注入方案优化问题, 建立了聚合物驱最优控制模型. 该模型以利润最大为性能指标, 以聚合物驱的渗流力学方程为支配方程, 并以聚合物最大用量约束和聚合物注入浓度的上下限约束为不等式约束条件. 各段塞间的注入浓度、段塞尺寸及驱油结束时间为该最优控制问题的优化变量. 对于该分布参数最优控制问题, 提出了一种变阶长迭代动态规划算法. 首先引入标准化的时间变量, 将原自由终端时间的聚合物驱最优控制问题转化为固定终端时间问题, 然后采用经典的迭代动态规划算法求解, 实现了注入浓度、段塞尺寸及驱油结束时间的同时优化, 最后通过实例验证了所提出算法的有效性.

Dynamic optimization of polymer flooding based on iterative dynamic programming with variable stage lengths

Polymer Hooding is an important technology for enhanced oil recovery.In this paper,an optimal control model is built for making the dynamic injection strategies of polymer flooding,in which the maximum of profit is as the performance index,the fluid flow equations of polymer flooding is as governing equations,the maximum polymer usage and bound constraints of polymer injecting concentrations are as inequality constraints.The size and concentration of slugs,and the ending time of polymer flooding are chosen as control variables.For this distributed parameter optimal control problem,an iterative dynamic programming with variable stages numerical algorithm is proposed.Firstly,the free final time optimal control problem of polymer flooding is transformed into a fixed final time problem by introducing a normalized time variable.Then the size and concentration of slugs,and the ending time of polymer flooding are optimized at the same time using classical iterative dynamic programming.Finally,the numerical results of an example illustrate the effectiveness of the proposed method.