A simple model for computer-aided optimization and design of sucker-rod pumping systems

Abstract

Design or optimization of a sucker-rod pumping system requires an evaluation of the system performance under different operating conditions. The precise evaluation of the performance is a complex task. A dynamic behavior of the sucker-rod string and complex interactions between components of the system and fluids in motion have to be taken into consideration. In this paper, a simple model of a sucker-rod pumping system is presented, and performance and applications of the model are outlined. A comprehensive, mathematical model of the system accounts for fluid and rod string dynamic behavior. Approximate surface and downhole dynamometer cards, production rates, downhole and surface forces, and energy consumption of sucker-rod pumping system are simulated with high accuracy for a variety of operating conditions. The model is defined by a system of linear algebraic equations derived from the straightforward Bergeron method rather than from numerical differentiation of wave equations. Example results of modeling indicate a good agreement with field data. The model was used to optimize an existing sucker-rod pumping system. Example results indicate significant savings over unoptimized operation. The model may also have an application at the design stage of the sucker-rod system development. The outline of the design procedure with application of the new model is presented.