Zimo Lin (Master of Science in Petroleum Engineering)
Experiments, CFD Simulation and Modeling of Fluid Viscosity Effect in Electrical Pump
Conclusions and Recommendations
A 12-stage mixed type electrical submersible pump (ESP), referred to as MTESP, was tested with single-phase water and industrial lubricate oil in a 2-inch closed flow loop. Experiments with different rotational speeds, different temperatures, and different flow rates were conducted and boosting pressure, temperature, and fluid volumetric flow rates were recorded during the test. Fluid viscosities up to 390 CP were tested with pump rotational speeds of 3600, 3000, and 2400 rpm. Oil viscosities changing with temperature were tested using rotary viscometer. As the viscosity increases, the ESP performance degrades.
Numerical simulation for two mixed-type ESPs, MTESP and DN1750, was conducted under viscous condition and validated with experimental results. The numerical simulation tends to overestimate the results in an acceptable range. ESP head performance from 1 CP to 1000 CP was obtained in numerical simulation to study the viscosity effect for the two pumps. The pump head curve is affected by fluid viscosity at low flow rates for mixed-type pumps was observed from numerical study.
An improved mechanistic model based on Euler equation is presented. The model predicts pump head performance for all fluid properties and pump types. A correlation for Euler head based on fluid viscosity and pump specific speed, and viscosity effect on turn loss is included in the improved
model. The model results agree with the water and viscous fluid experiment data for two mixed-type pumps (MTESP and DNI 750) and one radial-type pump TE2700.