Jose Gamboa (Doctor of Philosophy in Petroleum Engineering)
Prediction of the Transition in Two-Phase Performance of an Electrical Submersible Pump
Directed by Dr. Mauricio Prado
286 pp., Chapter 6: Conclusions and Recommendations
(261 words)
Two-phase flow behavior of an electrical submergible pump (ESP) stage has been studied experimentally and theoretically.
Experimental data have been collected from both an actual 22 stage ESP and also from a transparent laboratory prototype stage that allows visual observations and video recording. Models have been developed for predicting the maximum and Sauter bubble diameters in an ESP stage, the flow pattern transition boundaries between the homogeneous and the bubbly regimes, and the transition to surging. Also, correlations have been developed for open flow boundaries.
The data acquired from the actual ESP demonstrate the effect of volumetric gas fraction, rotational speed and intake pressure on the two phase stage performance of an ESP. The volumetric gas fraction mildly deteriorates the stage performance until it becomes severe when the volumetric gas fraction reaches a critical value, causing the surging phenomenon. The rotational speed and intake pressure affect the critical volumetric gas fraction at the surging conditions. Increasing the rotational speed and intake pressure move the critical volumetric gas fraction (and surging) toward higher values, expanding the pump operational window. Flow visualization and video recording through the transparent prototype stage shed light on the two phase flow behavior phenomena in an ESP, especially the formation of a stagnant gas pocket that causes the surging.
The developed models and correlations capture the effect of liquid rates, rotational speed and intake pressure on the surging transition boundary. These set of model and correlations are the first to be able to predict correctly the effects of all those variables on the conditions that lead to surging.
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