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Amrin Fadila Harun (Doctor of Philosophy in Petroleum Engineering)
The Effect of Inducer Performance on the Efficiency of the ESP Rotary Gas Separator
(158 pp.- Chapter VII)
Directed by Dr. Dale R. Doty and Dr. Ovadia Shoham
(343 words)

Electrical Submersible Pumps (ESP's) represent a common artificial-lift device used in the oil industry. One of the limitations of an ESP is its inability to handle more than a certain amount of free gas without head generation severely deteriorating. One way to maintain the performance of an ESP when handling free gas is to install a downhole rotary gas separator (RGS).

A mechanistic model to predict RGS efficiency was developed by Alhanati in 1993. Based on his model, a typical RGS efficiency curve has three distinct regions: high, transition and low. The high efficiency region reflects the separation efficiency in both the annulus area and inside the centrifuge chamber. The low efficiency region represents only the separation efficiency in the annulus. The transition region represents the condition at which the inducer is no longer able to produce enough head to compensate for the pressure drop across the gas outlet port. The location of the transition region depends strongly upon the head generated by the inducer section.

One limitation of Alhanati' s simplified model is the lack of information it provides about the inducer performance--specifically, how the inducer head generation is affected by geometry, operating conditions and fluid properties.

The main goal of this study is to improve Alhanati' s simplified model by providing a mechanistic model that can better generate the inducer head curve, so that the location of the efficiency transition region can be better predicted.

A field-scale experimental facility was constructed at The University of Tulsa Artificial Lift Projects (TUALP). Single and two-phase experimental data were gathered using air and mineral oils.

A two-phase inducer flow model is based on a two-fluid model and the meridional flow solution. This inviscid formulation incorporates a liquid displacement correction when phase segregation occurs.

The new inducer model was incorporated into Alhanati' s simplified model. This modified model exhibits better agreement with the separator efficiency experimental data for both water-air and hydrocarbon-air data. Finally, the improved model is more general than Alhanati 's because it is able to predict separation efficiency for different types of rotary gas separators.

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Last updated September 04, 2012