Optimal control of polymer flooding injection under nonlinear inequality constraints

In order to implement the exploration schemes of polymer flooding economically, the optimal control problem (OCP) is investigated to determine the best injection strategies. The performance criterion is chosen as profit grained from enhanced oil recovery, and the average cost is considered as a nonlinear inequality constraint. The OCP is governed by a distributed parameter system (DPS), which is described by two-dimensional (2-D) fluid equations in porous media. A control vector parameterization (CVP) based approach is presented for solving the OCP numerically and the nonlinear inequality constraint is handled by penalty function method. An example of a 2-D polymer flooding process is solved demonstrating the effectiveness of the given method.