You Don't Know Pumps: Myths and Truths about ESP Operation in High-Gas Environments

Abstract

Abstract ESP's are a technology that was adapted from water pumping in order to continue to produce high-rate, high-water cut wells with economic results. Using centrifugal pumps in wells that produce hydrocarbons creates the possibility, perhaps the inevitability, of centrifugal pumps that need to produce multiphase fluid, and originally this was a common limitation for their use. Gradually, the industry developed solutions to increase the capacity for ESP's to work in the presence of gas through technology (static gas separators, dynamic gas separators, and most recently multi-phase pump stages) and through simulations of ESP's in high-gas conditions to understand their behavior. The result is a set of historical concepts on the performance and behavior of ESP's with high-gas that gets passed down among generations of engineers who work for suppliers and producing companies. This paper's premise is that many of the beliefs about how ESP's operate in high-gas environments are mythological. They are learned early by engineers in the industry and accepted as true and unquestioned, even when presented with direct evidence that contradicts them. This paper will use conflicting examples to demonstrate that behavior is much more complex and unpredictable than previously considered. Perenco is an independent oil company whose strategy is to reinject life into mature oil assets. ESP's are a central part of Perenco's business because they offer an opportunity to boost flow rate for older wells with decreased reservoir pressure and high water cuts. Converting high-gas wells to ESP's has resulted in the opportunities for the examples in this paper.