Integrated fault diagnosis method for down-hole working conditions of the beam pumping unit

The Dynamometer card is commonly used to analyze down-hole working conditions of the beam pumping unit in the practical oil production. In order to improve the reliability and comprehensiveness of the computer diagnosis method, an integrated fault diagnosis method is proposed in this paper. First, the surface dynamometer card is transformed into the down-hole dynamometer card using the Fourier coefficient method by solving the one-dimensional wave equation; second, feature extraction of the dynamometer card is done using the Freeman chain code method; then, four different fault diagnosis methods are separately used to obtain different conclusions, that are, the curve moment and PSO-SVM based method, the curve moment and matter extension based method, the Freeman chain code and DCA based method, and the improved fuzzy ISODATA dynamic clustering based method; finally, a fusion decision method for multiple sources based on the weight optimization is proposed to integrate all conclusions, which can not only improve the focus ability but also decrease the conflict degree. Case study shows that the proposed integrated fault diagnosis method can obtain the reliable and comprehensive conclusion.