The increasing use throughout the world of multiphase twin-screw pumps in oil fields demands efficient methods to predict the pump performance at different operating conditions. A review of the literature revealed that existing models are cumbersome to use by reservoir and production engineers to model pump performance as part of the overall production system.
A model has been developed to predict the performance of multiphase twin-screw pumps that does not require the knowledge of the three different clearances existing within the pump internals that has limited the application of previous models. The proposed model uses the single-phase water performance data to calculate an effective circumferential clearance and predicts performance at any operating condition.
A unique field-scale laboratory was constructed at Texas A&M University in which Bornemann and Flowserve twin-screw pumps were installed and tested. The model showed an excellent agreement between the predicted results and the experimental data (air-water and air-gelled water) gathered, as well as with published data (air-water, and single-phase oil). The model is used to examine the effect of fluid viscosity, gas-volume fraction, speed and suction pressure on pump performance.
Additionally the application of multiphase pumping as a method to increase the oil production rate in a well is considered, and a reservoir model to forecast oil production from under-saturated solution gas-drive producing at constant bottomhole pressure was developed.