This paper summarizes the results from a high-temperature test program completed in late 2009 and discusses a new electric submersible pumping (ESP) configuration that was validated by ConocoPhillips for operations at 250°C and planned for 2010 field trials. This new prototype ESP system was jointly tested by ConocoPhillips and Schlumberger for 42 days in the C-FER Technologies high-temperature flow loop at fluid temperatures ranging from 150°C to 260°C, and at 250°C and above for approximately 40% of the total time.
While the primary objective of this test program was to validate this ESP system for use in 250°C fluid temperatures, the additional instrumentation at the test facility also offered an opportunity to investigate the temperature dynamics of the fluid flowing past the motor, and the pressure and temperature behavior of the motor. The test data was also compared to data from a similar test completed in 2008 and the evaluation provided some interesting observations, which will be discussed.
The information in this paper will be of value to any operator that has ESPs installed in high-temperature applications. In addition, the lessons learned from this test program may also be used to increase ESP reliability in conventional applications.
In 2008, a commercially available ESP system rated for a maximum fluid temperature of 218°C was tested (Noonan et al, 2009) to validate its published ratings and take it beyond its published rating to help define the technology gap needed for operation at 250°C. The 2008 ESP test provided several important findings, which included highlighting the importance of directly monitoring the internal motor winding temperature of the ESP motor, as this was a key parameter during the evaluation. The dismantle, inspection and failure Analysis (DIFA) of the failed system also provided critical information of performance by individual components. At the conclusion of this test, both companies agreed to another partnership to validate a new ESP prototype designed for higher temperatures in the CFER flow loop during 2009.
While the 2009 test program included a series of performance curves at different speeds and temperatures, similar to the 2008 test, it also focused on several additional tests. For example, the 2009 test program focused on higher test fluid temperatures, more 24- hour continuous testing, and new thermal cycling tests that were not previously attempted. Based on the lessons learned from the 2008 test, the 2009 program was also structured to better understand
o temperature dynamics of the fluid flowing past the motor
o motor skin temperature dynamics (heat transfer to the fluid)
o internal and external temperature and pressure differentials of the motor.
The 2009 test program commenced in September and ran without incident or equipment failure for 42 days. Upon removal of the ESP prototype from the flow loop, a full dismantle and inspection was made of the ESP equipment to determine any areas of concern in terms of operability or reliability that would prevent this prototype from being cleared for field trial.