Abstract
High-speed operation of electric submersible pumps (ESPs) are becoming common practice in oilfield operations. Installing high-speed high gas volume fraction (GVF) multiphase pumps (MPPs) will facilitate production from wells with high gas content. This study uses gas-liquid parameters to obtain dimensionless curves from various physical tests of high-speed, high GVF MPPs. The application benefits include sizing by field and design personnel to ensure required production delivery at the desired MPP setting depths.
Two high-speed, high GVF MPPs, with 4.00-inch and 5.38-inch housing diameters, were physically tested and operated at 6,000 revolutions per minute. For the 4.00-inch housing MPP, the intake pressure varied from 26 to 70 psig, whereas intake pressure was 46 psig for the 5.38-inch MPP. The range of water volume flow rate was 63 to 660 barrels per day (BPD), and intake GVF varied from about 84% to 98%. Energy and turbomachinery principles were applied to the test data to obtain dimensionless head and flow performance curves for each MPP. The curves were validated from estimating pump boost pressures.
The results showed that the trend in variation of dimensionless head coefficient with the dimensionless volume flow rate depends on the method in which the tests were performed. For the 4-inch MPP, tested at constant liquid volume flow rate while varying intake pressures and GVF, the dimensionless head coefficient increased with increasing dimensionless volume flow rate. It was observed that all the dimensionless test data collapse on one another. For the 5.38-inch MPP, tested at constant intake pressure while varying liquid and gas volume flow rates, the dimensionless head coefficient decreased with increasing dimensionless volume flow rate. All the dimensionless test data for the pump were also observed to collapse on one another. Validation of the dimensionless performance curve for each MPP showed that the curves can be used to determine, with good accuracy, dimensionless head coefficients and corresponding pump boost pressures for given flow and operating conditions. In conclusion, the method presented in this study has beneficial field design application in establishing performance of high-speed MPPs operating in high GVF environments.
This study highlights the benefits of obtaining dimensionless characteristics in general and specifically for high-speed, high-GVF MPPs, using fundamental, physics-based techniques. Application of the performance curves obtained from this technique can be used by design engineers and field personnel to size high-speed, high-intake GVF MPPs operating at any setting depths. This is beneficial to the operator to optimize production and maximize the economic bottom-line from the field asset.
