Introduction

Now that all the important calculation methods available for the determination of operational conditions in sucker-rod pumping have been covered, the present chapter discusses the use of these procedures in the basic design of a rod pumping system. System design, as defined here, involves selecting the proper equipment components and determining the main parameters of a pumping system, in order to achieve the goals set forth by the operator and to ensure an economical fluid production.

The aim of artificial lift design is to ensure the most economical means of liquid production within the constraints imposed by the given well and reservoir. For sucker-rod pumping, this usually means selecting the right size of pumping unit and gear reducer as well as determining the pumping mode to be used, i.e., the combination of the plunger size, stroke length, pumping speed, and rod string design. The size of the pumping unit and gear reducer can only be selected if the operating conditions (loads, torques, etc.) are known, which vary with the different pumping modes. Therefore, the basic task of a proper design lies in the optimal determination of the pumping mode.

For surface pumps (e.g., mud pumps), the calculation of the required plunger size, stroke length, and speed is quite straightforward. This is because pump displacement is a direct function of these variables, and they can be changed at will. The situation is dramatically different in the case of sucker-rod pumps because downhole pump stroke length is far from being equal...