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20 SUCKER ROD PUMPING

According to a recent survey, there are, in the United States,
approximately 574,000 producing oil wells, of which some 68,000 are
flowing. Of the 506,000 wells on artificial lift, a vast majority (80 to
85 per cent) are being produced by sucker rod pumping. Proper design
and maintenance of sucker rod pumping installations can, therefore, be
recognized as of major importance in the field of oil production. In this
chapter we propose first to introduce certain theoretical expressions
used in pumping calculations, then to present a method for the design
of pumping installations, and finally to discuss methods of analyzing
pumping installations to obtain the most efficient performance with
existing equipment.
A necessary prerequisite for solving problems of design and
analysis is a good understanding of the component parts of a
pumping installation. These parts are the prime mover, the surface
pumping equipment, the sucker rod string, and the subsurface
pump (Fig. 20.1). Although each component will be treated (in the
descriptions which follow) as a separate unit, it cannot be
emphasized too strongly that the installation is in reality a very
complex linkage of the components and that no single component
can be designed independently of the others. Thus, the complete
design of a pumping installation becomes a difficult, trial-and-
error affair, and even with the theoretical equations as guideposts,
it is often necessary to resort to empirical equations and techniques
based on experience.

The Subsurface Pump

The functions of the pump are to admit fluid from the
formation into the producing string and (primarily) to lift the fluid
thus admitted to the surface. To accomplish this, any pump must
contain four essential elements. As shown in Fig. 20.2 these
elements are the working barrel, the plunger, the standing valve,

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