Got Steam? Understanding ESP Steam Handling Capabilities in the Centrifugal Pump

Abstract

Abstract The successful development and implementation of high temperature Electric Submersible Pump (ESP) technology for Steam Assisted Gravity Drainage (SAGD) applications has allowed operators to reduce their flowing bottom-hole pressures and achieve higher production rates. However, operating under these conditions brings the Pump Intake Pressure (PIP) closer to the saturation pressure of steam, which can result in live-steam production through the pump. The effect that live-steam has on pump performance is not particularly well understood, and has been a key challenge for operators when designing and optimizing ESP systems for SAGD applications. In early 2011, ConocoPhillips, Baker Hughes and C-FER Technologies embarked on an experimental test program to determine the consequences of producing live-steam through a centrifugal pump. This new program was meant to build on multi-phase work that had begun over a decade ago at the University of Tulsa (TU), where researchers had focused on experimentally measuring the two-phase flow performance of ESP stages with air and at moderate temperatures [Pessoa and Prado 2001]. The TU work ultimately resulted in a wave of new technology aimed at increasing ESP gas handling capabilities. Following a similar testing and ESP instrumentation philosophy, this new collaboration looked to build upon the TU experiments and expand the test fluids to include live-steam, water, and air at higher temperatures. This ultimately involved the design and construction of a unique high temperature Steam Flow Loop that allows for live-steam injection into a centrifugal pump, while monitoring both head and performance degradation. This paper will reveal some of the unique test results collected with the first pumping system, including snapshots of the stage-by-stage pressure contributions captured in real-time as air or air and steam migrates through the ESP being tested. These results also demonstrate the impact the presence of other gases can have on steam flashing and how it is important to consider both the gas and steam vapor effects in SAGD ESP designs.