A Review of the Non-Dimensional Pumping Parameters and Their Use in Sucker Rod String Design

During recent sucker rod pumping problem solving schools presented at the SouthWestern Petroleum Short Course, it has become apparent that few engineers and operators know about the non-dimensional pumping parameters developed by Sucker Rod Pumping Research Inc. and provided to the industry in API RP 11L for rod string designs.

This paper will discuss the background and physical meaning of the two main parameters Fo/Skr and No/No’, show the nomograph of their inter-relationship, and provide recommended limits which are typically not provided in modern rod string computer programs. These limits may assist in reducing sucker rod system failures. The relationship of these design parameters to the dynamic motion of the sucker rod pumping system and the formation of undertravel or overtravel dynamometer cards will be provided. Additionally, a comparison of sucker rod string
design recommendations, resulting sucker rod system failure frequencies per year and a discussion of operating practices will be provided.