The design of production facilities is generally based on extrapolations from the results of exploration well tests, delineation wells and reservoir characterization. As a result, when the production wells are drilled and completed, actual production data may be different from predictions. This long term evolution is induced by the natural reservoir depletion. Well instabilities can also contribute to changing flow and pressure conditions at pump suction. Therefore a multiphase pump should be designed for variable inlet conditions.
Operational flexibility is preferable to efficiency optimization for a narrow operating band only.
The following description concentrates on the main characteristics of the low speed range, which is considered for the case study included in this article. Each compression stage consists of an impeller mounted on a single rotating shaft, followed by a fixed diffuser. The impeller blades have a typical helical shape. The profile of the open type impeller and diffuser blading arrangement is specifically designed to prevent the separation of the gas-liquid mixture during the compression process. The hydraulic passages accommodate solid particles in suspension, and special care has been taken in the design to prevent their accumulation in the pump casing.