Motor Power Based Inversion of Dynamometer Cards Using Hybrid Model

The dynamometer card sensors' poor real-time performance and high maintenance costs limit the control and diagnosis for sucker rod pumps(SRP) in oil exploitation. The motor which is the power source of the whole pumping process can reflect the working state of the entire equipment. The motor power can be accessed easily and continuously. Thus, this paper proposes a method to measure the dynamometer cards based on the motor power. Firstly, a mathematical function relationship between the polished rod load and the motor power is established by fully considering many crucial factors in this process. Moreover, the data is compensated by the support vector machine for the top and bottom dead centers and the error of the mechanism model. At last, the proposed method is validated by a set of motor power data collected from wells by a self-developed device. The experimental result demonstrates the effectiveness of the proposed method for the inversion.