The Progressing Cavity Pump Operating Envelope: You Cannot Expand What You Don't Understand

Abstract

Progressing cavity pumps (PCP) have been the preferred method of lift for cold heavy oil production for years. They were generally not considered a complex technology, unlike electric submersible pumps for example, and this resulted in many misapplications and poor performance. Until the PCP industry started to push the envelope in terms of landed depth, production volumes, gas handling, viscosity and aromatics, that testing programs emerged to understand the science behind PCP performance under various conditions. This paper will describe some of the recent findings from these test programs that will help to better select and design a PCP system for heavy oil. Some of this work includes understanding gas handling capabilities, rod string torsion, elastomer swell, metallic stators, and the effects of speed and rotor - stator fit on PCP run life. The PCP industry has also been plagued with the lack of a "common language" which makes communication of lessons learned and data sharing difficult. This paper will describe the efforts of a group of operating companies to standardize nomenclature and data parameters to facilitate analysis and benchmarking to identify areas for improvement and gaps for technology advancement. This paper will also provide information from the group of PCP users and manufacturers that worked together since early 2006 to create comprehensive international standards and recommended practices for the manufacturing and testing of these pumping systems. Background Other forms of artificial lift, such as beam pumping and gas lift have been used in the oil industry for more than 50 years. One would assume that those technologies are well understood, however within the last 5 years publications from performance tests have changed the way even those lift methods are viewed. For beam pumping, the industry now has a better understanding of fluid slippage in the pump 1 as well as static gas separator performance 2, and this knowledge has changed the way the industry sizes and selects pumps and gas separators. For gas lift valves, testing completed to quantify valve performance 3 has changed the way the industry now designs gas lift systems. For decades, engineers have been using "rules of thumb" for selection and sizing of artificial lift systems. The origins for many of these "rules of thumb" or common practices have been lost over the years. Both operating companies and manufacturers of artificial lift equipment have been spending more time and money in the past decade towards understanding artificial lift performance to increase lift efficiency and improve equipment reliability. In 2007, the Society of Petroleum Engineers published a revised Petroleum Engineering Handbook (Volume IV) that includes many of these advancements and understandings of lift performance for the common forms of artificial lift.

Numerical Simulation about the Effect of Stator Pitch and StatorThickness on Contact Pressure of Progressive Cavity Pump

“…Noonan mentioned our lack of adequate cognition of PCP's applications and operating range and proposed that "the industry is striving to understand PCP performance in a variety of environments and operational limits". She also added that "while the industry is much further ahead on the PCP learning curve as they were 10 years ago, there is still much that needs to be understood, especially pump pressure capability, and PCP system reliability" [2]. The pump pressure capability is one key performance parameters of PCPs, for the excellent pump pressure capability can effectively prevent internal slip which will lead to bad measuring accuracy.…”