Juan Carlos Serrano (Master of Science in Petroleum Engineering)
Natural Separation Efficiency in Electric Submersible Pump Systems
(83 pp. – Chapter VII)
Directed by Dr. Dale R. Doty
(193 words)
In an electrical submersible pumping installation, the amount of free gas at the pump depth needs to be monitored, since free gas considerably affects the performance of the centrifugal pump. When gas separation equipment is not installed, the bottomhole gas separation efficiency, which is the fraction of the produced free gas vented through the annulus, is determined by the natural gravitational gas separation within the annulus.
The objective of this research study is to quantify this natural separation efficiency as a function of well inclination angle, pump intake pressure and gas and liquid flow rates. A field scale experimental test facility was built and experimental data were collected, using air and water as the working fluids. The experimental conditions included liquid flow rates up to 2000 bpd, gas volume percentages up to 20%, intake pressures up to 1 50 psig and inclination angles from 90 degrees (vertical) to 30 degrees.
The experimental data indicate that natural separation efficiency increases as the liquid flow rate, the gas flow rate and the inclination angle (measured from horizontal) decrease. A simplified model was developed to predict natural separation efficiency over the full range of the experimental data.
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