PMM-PCP Field Trials Using a New Generation Permanent Magnet Motor Technology

Abstract

Abstract The recent proliferation of horizontal and deviated wells along with the low rates being produced by many of the newly completed shale oil wells has created a need for a very efficient pumping system capable of operation below deviations or even in the horizontal. As with all technologies, new materials of construction, new manufacturing processes and new innovative ideas result in the evolution of many systems used in the past. Often times, the needs of our industry demand and direct these innovations as well. Operating companies look for more efficient deployment methods as well as equipment that can operate in ever more demanding environments. The tried and true technologies that are currently being used are no longer enough to meet these new demands. It is during these times, when major innovations occur to allow for completions and production methods to change significantly. Such is the case in the downhole Progressing Cavity Pumping (PCP) industry. Initially used in industrial applications in the 1930's and adapted for downhole applications via conventional sucker rods in the 1980's, PCP applications eventually evolved into bottom-drive PCPs via a downhole electric submersible motor; hence the term ESPCP – Electric Submersible Progressing Cavity Pump. ESPCPs combined PCP technology with ESP technology thereby eliminating the need for sucker rods thereby widening the application envelope to deviated and horizontal wells within which conventional rod-driven PCPs have inherent limitations. The utilization of "standard" induction motor technology necessitated the need for a speed reduction from the synchronous speed of the ESP motor, to that of the PCP (typically in the range of 100 – 500 RPM). In this case, it was the use of a downhole gear reducer. This gear reducer accounted for the speed requirement differential between standard ESP and standard PCP operational speeds. In the continued evolution, the downhole ESPCP gear reducer became a costly component and one of the most likely failure points in the system. The introduction of 10-pole submersible permanent magnet motors (PMMs) eliminated the need for an additional piece of downhole hardware. Between 2007 & 2008, a number of permanent magnet motors had been combined with progressing cavity pumps and successfully implemented (PMM-PCP)1. More recently however, a new generation PMM has been developed that is better suited to be combined with PCPs. This paper will present the results of successful field trials pulling from a large population of wells but focusing on a few key wells to show the improved MTBF.