ConocoPhillips has been on a quest for a high-volume artificial lift system that will operate reliably in a 250°C (482°F) downhole environment. This paper will describe the testing and results of a high-temperature electric submersible pump (ESP) system in a flow loop built to validate downhole equipment for thermal applications, primarily for steam assisted gravity drainage (SAGD) developments. What makes this test program unique from previous tests is the longer duration (4+ weeks), the range of fluid temperatures (90°C to 245°C [194°F to 473°F]), and the type and volume of data collected. One of the key parameters monitored and documented was the internal motor winding temperature, which has been used to validate and calibrate a simulator for predicting motor performance in thermal environments. Background The group was tasked to find, select, and further support the development of artificial lift technology with the capability of handling fluid rates up to 1,000 m3/d at 250°C [6,290 B/D at 482°F] downhole conditions. The goal was not to just find and validate a single system, but to qualify several lift systems to provide the production engineers with a toolbox of solutions. This challenge was approached as two different projects: find, select, and further develop potential lift systems with the needed volumetric capability; and validate these systems through high-temperature testing. The latter was considered to be the bigger challenge. ConocoPhillips did not operate any fields with downhole temperatures close to 250°C [482°F], so validation via field trial was not possible. A more controlled test facility was preferred, so that a comprehensive suite of performance curves could be collected to define the full operating envelope for each lift candidate. A test facility that was not associated with a specific pump vendor was also preferred to avoid the legal and confidentiality issues with testing third-party equipment. It was decided that an existing high-temperature flow loop located at C-FER Technologies Ltd, in Edmonton, Alberta, Canada, was the best option for the artificial lift validation testing. The loop had been built as part of a joint industry project (JIP)1 in 2004, but needed to be upgraded for testing at 250°C [482°F]. ConocoPhillips contracted C-FER and funded the project entirely. Two lift systems have been tested to date in the flow loop after the high-temperature upgrade was completed in mid-2008. This paper focuses on the results of the second test program, which evaluated a Schlumberger high-temperature ESP system, developed for operation in thermal environments. Introduction In 2008, there were no commercially available ESP systems rated for 250°C [482°F] downhole environments. So, one of the existing systems was selected for testing to fully understand what would happen to the ESP components when the system was operated at or beyond the maximum temperature rating. The results would help determine how close the existing technology really is to reaching operation at the 250°C [482°F] target temperature, and, depending on the outcome, to help direct research funding into the appropriate places.

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.

If you're reading this, then it's likely that your first reaction to the paper's title was something along the lines of ‘oh no, not another paper on reliability’. Believe me, I totally understand: ESP reliability – something that is fundamentally important to both ESP suppliers and end users – often gets treated in technical papers with unnecessarily complex and arcane mathematics. Fundamentally, however, it can be and should be kept reasonable so that everyone can discuss it using the same concepts and terms. This paper, therefore, will not try to create complicated new metrics. It will use existing runlife analysis techniques to analyze Perenco's entire ESP history and to highlight how different measures can be used in different ways. At each step, the paper will compare the results of the various measures to expectations in order to gain some real evidence-based insight into ESP reliability, which is often surprising. Next, the paper will create logical conclusions based on this evidence that potentially apply to general ESP reliability behavior. And finally, based on those conclusions, the paper will address the implications on how to manage ESP's. Before getting started, it's important to emphasize a couple points about reliability analysis. The first point is that there is no single evaluation that will tell you everything you want to know about reliability. There are many different analyses possible because there are many different questions to address on reliability, such as: ‘which ESP's are at risk?’ ‘are we improving?’, ‘did this change make a difference?’, or ‘how many ESP failures should I plan for?’ The second point is that, because of this inherent diversity in analysis, and despite my feeling that the subject can be kept at a level most people can understand, there will always be a certain level of complexity to statistical evaluation. It takes time to explain and understand, and this can be difficult to condense into a 5-minute ‘elementary school level’ presentation, as is often requested.