Currently, beam pumping unit has become a research hotspot in the oilfield area. Nevertheless, filling process of the pumping unit horsehead causes large-amplitude variations of the motor toque and greatly reduces the efficiency of the system. This paper presents a new-type hydraulic-motor hybrid system which can store the hydraulic energy and realize power recovery of the beam pumping unit. Mathematical model is built and verified by experimental studies. Experimental and simulation results show that, first of all, energy recovery function of the designed hydraulic-motor hybrid system is demonstrated to be effective; besides, hydraulic pressure of the hybrid system should be set at the range of 15–25 MPa, and the system efficiency can be over 80%; what is more, in order to optimize the component efficiency, maximum displacements of the hydraulic pump and motor are considered to be respectively set higher than 70 cc/r and 40 cc/r; last but not the least, synchronous speed value of the hybrid system should be settled high to some extent to ensure the efficiency of the whole system as well as the components. This optimization method can be set forth in the optimization design of the beam pumping unit.

目前，束流抽油机已成为油田领域的研究热点。然而，抽油机机头的注油过程会引起电动机转矩的大幅度变化，并大大降低了系统的效率。本文提出了一种新型的液压马达混合动力系统，该系统可以存储液压能并实现梁抽油机的动力回收。建立了数学模型，并通过实验研究进行了验证。实验和仿真结果表明，首先，所设计的液压马达混合动力系统的能量回收功能被证明是有效的；此外，混合动力系统的液压应设置在15-25 MPa的范围内，系统效率可以超过80％；此外，为了优化组件效率，液压泵和马达的最大排量应分别设置为高于70 cc / r和40 cc / r；最后但并非最不重要的一点是，应在某种程度上将混合动力系统的同步速度值设置得较高，以确保整个系统以及组件的效率。这种优化方法可以在光束泵浦单元的优化设计中提出。