Abstract

Proper electric submersible pump (ESP) design in wells producing high viscosity crudes can result in improved production performance and extended pump life.

This paper presents a practical, low cost technique which allows the engineer to determine optimum ESP configurations for wells producing crude oil with viscosities significantly greater than water (1.0 cp).

The use of downhole pressure sensors coupled to ESPs enable real time observation of pump intake pressures. The pressure information can be used in the following ways:

• Inflow performance relationship can be hgenerated from pump intake pressure and rate data for optimizing ESP size.

• The correct number of stages required for necessary well drawdown (production) can be calculated by detemining the actual head produced by the pump as calculated with the downhole sensor.

Our studies indicate that the number of stages required to achieve the desired drawdown at water cuts less than 50% is considerably greater than the number calculated using vendor supplied head capacity curves. High viscosity emulsions (in excess of 100 cp) are believed to be responsible for causing the low head values observed in the Bima field.

Since many parameters affect the formation of emulsions, the actual measurement of pump performance using the downhole pressure sensors is preferred over laboratory measured viscosity and literature values.

One of the objectives of this paper is to foster an awareness of the effect that high viscosity crudes can have on ESP designs. Detection of the viscosity problem early in the life of a development project can lead to immediate and profound production benefits.