Optimization and Application of Reciprocating Direct-Drive Electric Submersible Plunger Pump Lifting System in the Xinjiang Oilfield

A reciprocating direct-drive electric submersible plunger pump (RDD-ESPP) lifting system is an innovative rodless lifting method, which uses a downhole linear motor to directly drive the plunger pump to lift the fluid. This method effectively overcomes the problems encountered in a conventional sucker rod pumping system, such as severe eccentric wear between the sucker rod and the tubing, higher energy consumption and frequent pump maintenance. In this manuscript, the objective is to propose a methodology on optimizing the working parameters of RDD-ESPP lifting system and validate the theory with field case. Mathematical models for the wellbore temperature distribution, lifting load, pump efficiency, system efficiency and tubing strength validation are established. A selection process for the optimal working parameters is proposed, and a parameter sensitivity analysis is implemented. The results show that pump efficiency is largely affected by gas and leakage, and there are reasonable pump submergence depths in oil wells for different produced gas-to-oil ratios. A field application test in a low-production well resulted in a 33.5% power savings rate and 41.6% improvement in the pump efficiency. RDD-ESPP lifting system has a promosing potential on power savings and consumption reduction compared with conventional sucker rod pumping system.