Economic Considerations for Sizing Tubing and Power Cable for Electric Submersible Pumps

Summary Power consumption of an electric submersible pump (ESP) installation may be categorized into three components: the energy required to perform useful work, which is equivalent to the net hydraulic load divided by the product of pump and motor efficiencies; the energy absorbed by tubing friction, which is equal to the dissipated hydraulic energy divided by the efficiency product; and power-cable electrical losses. An improved design technique is presented that brings the first two categories into economic perspective. The interrelated effects of tubing friction, power-cable resistance, and motor voltage on ESP power consumption are demonstrated, as is the degree of desirability for using a motor of the highest available voltage. An equation, useful in making economic evaluations of alternatives, is developed for calculating power consumption for combinations of tubing size, power-cable size, and motor voltage. Variations of power consumption are illustrated graphically for various combinations of these three parameters. Also illustrated is the effect of the nature of a specific net hydraulic load—i.e., the product of rate, net lift, and specific gravity. Practical examples using the design techniques developed here are presented and comparisons made to designs based on common practice.