An alternative approach to the analysis of sucker-rod dynamics in vertical and deviated wells

A set of partial differential equations which consider the combined effects of fluid column, sucker-rod string and tubing motion were developed to describe the motion of a sucker-rod pumping system. tubing is fixed, only the fluid column and rod motion need be considered; however, when the tubing is free to move, energy in the system is lost and, therefore, pump system efficiency declines, hence, the need to consider these effects in the design of the sucker-rod system. finite differences this model was used to evaluate performance of sucker-rod pumps (pumping rate as a function of number of strokes, stroke length, rod length, ratio of plunger to cylinder diameter, etc.) in both vertical and deviated wells. sults indicate that the developed model simply and accurately models the dynamic motion of the sucker-rod string. The examples presented illustrate its general applicability in both vertical and deviated wells.