The Study Of Sensor Used To Measure Torqueandaxial Force Of Polish Rod On Progressing Cavity Pump

Progressing Cavity Pump(PCP) is a newly developed petroleum output system with distinctive feature of large advantage in high viscosity, high oil and gas ratio, high sand content and low yield fields oilfield. It also shows the superiority in common reservoir and high water drive reservoir oilfields. Compared with other oil recovery equipment, the features of smaller size, lighter weight, easier to manufacture, more efficiencient are making the application of PCP oil more and more popular all over the world. PCP is destined to have a broad prospect for development in petroleum output field.With the application of PCP, more and more widely, on-site technical staff found a high failure rate in the process of their work. The high failure rate greatly affected the efficiency of oil exploration. Therefore, real-time monitoring of pumping conditions become necessary. According to the existed relationship between PCP failure and various parameters shows that the torque and axial force are key parameters that reflect the working condition of the PCP. Because the engineering research of PCP is lagging behind, despite some academic and engineering developed a number solutions used to monitor working condition of the PCP system, there are problems that they have not been able to meet the requirements of PCP working condition.In this paper, we developed a sensor used on the polish rod of PCP to monitor the parameters of torque and axial force, research and design were as follows: According to the principle of the overall design of the sensor, we determined the proper torque, axial force measurement program, selected the schemes of data transmission between sensing element on the shaft and the sensor, communication schemes between the sensor and the host computer program. According to theoretical mechanics, fluid mechanics, empirical formula, we analysed the stress condition of the rod system, then we determined the size of the sensor based on the size of drive head and square shaft, established three-dimensional model of the sensing unit based on PRO/E, analysed stress and strain of the sesoring unit based on ANSYS to determine the location of strain gauges pasted and check the strength of sensing unit; We selected circuit components according to the design principle of the sensor, designed amplifier circuit, analog-digital conversion circuit and communication circuit; We developed the theoretical formula to find the relationship between sensor input and output, we programmed the microcontroller, and finally sensor calibration methods were discussed.The innovative points in this paper are as followed: We analysed the torque of the mast system with infinitesimal method; We analysed the stress and strain of the sensor based on ANSYS; We designed the packing scheme of the sensor based on the practical working condition; We analysed the problem of reference voltage of analog-digital conversion circuit and the problem of too many interfaces occupied by Single-chip Microcomputer, We developed the theoretical formula and finded the relationship between sensor input and output.