基于模糊故障树的螺杆钻具马达总成失效分析

螺杆钻具作为一种容积式井下动力钻具,由于其独特的工作原理和优异的工作性能,广泛应用于钻井现场。由于影响因素较多,其失效形式不宜准确判定。根据螺杆钻具在现场应用过程中出现的典型失效案例,引入了模糊故障树的分析方法,建立了螺杆钻具马达总成失效故障树。通过定性分析,得到了故障树的最小割集,确定了钻具马达总成在工作过程中的薄弱环节; 引用模糊故障树计算方法,对所建立的故障树进行定量计算,并以转子表面磨损和冲蚀失效事件为例,计算其发生概率的范围。为螺杆钻具的设计、制造和使用维修提供了参考依据。

Failure Analysis for the Motor of PDM Based on Fuzzy Fault Tree

As a kind of volumetric downhole power drilling tool, the PDM(Positive displacemetn motor)is widely used in the drilling site because of its unique working principle and excellent working performance, but its failure is not determined accurately because of the influencing factors. According to the typical failure cases of the motor of PDM appeared in application field, an analysis method of fuzzy fault tree was introduced,and a failure fault tree of the motor was established.Through the qualitative analysis,the minimum cut set of the fault tree was obtained,and the weak link of the motor during its working process was determined; Besides,a calculation method based on the fuzzy tree was proposed for its qualitative analysis,the surface wear and erosion failure of the rotor was taken to as example, its probability scope was calculated.which provides the reference basis for the screw drill in the design, manufacture and use maintenance.