Paper: Making the Most of Rod Design A Compression of Measured and Modeled Rod String Stresses

Several software programs are available to calculate a pump downhole load-position card from dynamometer data. Most of these programs use the wave equation, with various solutions (Fourier Series, Method of Characteristics, Finite Differences, etc.) to help set damping conditions. A downhole tool with strain gauges is available to measure the actual forces at the pump as well as mid-string. Use of this tool has led to providing actual downhole values much less than those predicted by the software programs. This paper will present the actual data collected by this downhole lead cell. This data will then be compared to load values calculated by these commercially available software programs.