Optimization of pump jack electric drive operation taking into account reservoir flow rate

The object of the study are the processes occurring in electric drives of sucker rod pumping units, which are used for mechanical oil production. When designing oil pumping units, one of the issues is the synthesis of control systems for the electric drives of pump jacks. In the synthesis of the control system, it is important to take into account as many factors as possible that influence the performance of the well and its equipment. When synthesizing the criterion for optimal operation of the system, it is necessary to take into account changes in the technical condition of the oil production facility and the conditions of the reservoir operation. This is implemented using a control system that adjusts the electric drive speed according to the real operating conditions of the well. This approach allows improving the productivity of the oil pumping unit and increasing its economic efficiency. The main focus is on the synthesis of a control system for the electric drive of a pump jack, which makes it possible to balance the intensity of fluid inflow into the well and its withdrawal. An optimization criterion is proposed, which takes into account different fluid inflow rates, thus adapting the electric drive operation to the specific conditions of each well. The study used the theory of classical variational calculus. To find the minimum of the functional, and therefore the optimal parameters of the control system, a quadratic form, which is a Lyapunov function, was used. The study resulted in the formulae for calculating the key operational parameters of the pump jack electric drive. The synthesized optimization criterion links the unit's productivity to parameters such as the number of crankshaft rotations, the rod pump delivery coefficient, and the load torque of the drive motor. In practice, the proposed optimization criterion for the electric drive operation will enable improving the efficiency of the oil pumping unit through the rational selection of the drive motor's speed and torque. This, in turn, will enhance the well's operating conditions and extend its operational life.