Are Variables In The Design Details Of Subsurface Rod Pumps Causing High Lifting Costs And Reduced Performance

There is a generally held opinion among the users of subsurface rod pumps that those pumps built to the specifications of API, Spec 11AX, have the following characteristics: 1. Their design is excellent with little need for improvement. 2. Equal quality can be obtained from various authorized manufacturers by simply specifying dimensions and materials in broad generic terms. 3. The individual design of pump parts has little or no bearing on pump performance. The author contends that these opinions are erroneous resulting in millions of dollars of unnecessary expense each year for the repair and maintenance of rod pumping equipment. To prove his contention he traces the history of the standardization program considering industry requirements, standardization goals, and the design options left open to the manufacturer/user team. He then discusses design details of some of the rod pump components that can cause major differences in pump performance and run time. In conclusion it is recommended that users consider all these factors to improve pumping system performance and reduce lifting costs.