Paper: Torque Analysis of Pumping Units Using Dynamometer Cards

A computer program has been developed which permits torque calculations in a much simpler and much accurate manner than previously presented in API publications. This is accomplished by using a highly accurate digitizing technique to input the necessary number of points from the dynamometer card. The proposed technique improves the accuracy of the data over manual input and allows a much greater number of points to be used for subsequent analysis. The program can handle all pumping unit geometries and calculates all the parameters for a complete analysis of the pumping unit: PRHP, PPRL, MPRL, PT, etc. The instantaneous torques are plotted vs. crank angle. The program also evaluates the counterbalancing of the unit by calculating the Cyclic Load Factor for actual conditions. The author proposes a new technique to find the maximum counterbalance moment needed for ideal counterbalancing. The theoretically sound procedure seeks that counterbalance moment which results in the least value conditions. of Cyclic Load Factor for the given This approach ensures the minimum of prime mover power requirements, installations, and can reduce the power consumption of existing thus improving the economy of sucker rod pumping.