Optimization of Partial-Pressure Periodic Water Injection in Oilfield under Time-of-Use Electricity Price

In order to reduce the throttling loss of the valve group caused by the inconsistent demand pressure of each water injection well, a mathematical model of partial-pressure periodic water injection under time-of-use (TOU) electricity price was established. The model took the lowest total energy consumption cost of the pump station as the objective function and the service requirements of the pump assembly in the station and water injection well outside the station as the constraint conditions. Modeling programming was performed with mathematical planning and a optimization general algebraic modeling system (GAMS). The embedded branch-and-reduce optimization navigator (BARON) solver was called to solve the problem. According to the actual water injection situation, two operation schemes of cross water injection and sequential water injection were considered in each pressure range, and the best water injection scheme was determined by comparative analysis. The results show that after optimization, the average throttling loss of low-pressure and medium-pressure water injection well group is reduced by about 7 MPa and 3 MPa, respectively. The partial-pressure periodic water injection under TOU electricity price has good economic benefits, which can reduce the energy consumption cost within one period by about 13000 yuan and greatly reduce the energy consumption cost caused by throttling loss in site. Compared with cross water injection, sequential water injection has better practical value and operability and can provide some reference for the actual operation and production of the site.