As the number of mature reservoirs continues to increase worldwide, so has the development of new technologies to aid electrical submersible pump (ESP) performance. Because depleting fields produce increasing gas volume, gas separators and gas handlers are necessary to maintain pump performance and production.

In wells with high gas volume, production is limited by the centrifugal pump’s ability to handle gas. Centrifugal pumps suffer from a head degradation and gas-locking in the presence of high percentages of free gas. Different technologies have been implemented to help operators achieve their production goals. However, as downhole conditions continue to change, the gas-handling capability of the technology installed becomes insufficient, resulting in downtime due to gas-lock, limited drawdown, high operational costs, high motor current fluctuations, and others issues.

A multiphase helicoaxial pump installed below the main production pump allows the production pump to efficiently handle higher percentages of free gas and up to 75% of gas volume fraction (GVF) at the first stage. This system is designed to improve stability in gassy wells, provide better slug handling in horizontal wells, increase the production rate and recovered reserves, and increase ESP effectiveness.

To enhance production in oil wells experiencing gas-locking problems, an operator began optimizing downhole ESPs where they showed unstable operational behavior and where the GVF was overcoming the maximum gas- handling capability of centrifugal pumps (up to 45% GVF).

In the first optimized ESP wells, the operator was able to increase production by reducing gas-locking production shutdowns, to stabilize motor current fluctuations, and to Increase production and reservoir life by increasing drawdown and allowing effective pump operation at lower intake pressure.

By the end of 2010, a total of 10 wells were operating with this technology within three different fields. Currently, more than 25 wells have been optimized.

The implementation of this technology in wells with high GLR has been demonstrated to be an effective solution. It has also allowed the operator to expand the use of the ESP in gassy wells, previously thought to be unsuitable for ESP application.

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