Over the past two decades progressing cavity pumping systems have experienced a gradual emergence as a common form of artificial lift. In the correct application, progressing cavity pumping systems provide the most economical, and in some cases, the only means of artificial lift. Although a large percentage of these installations continue to be in Canada, the use of PC pumps has spread rapidly throughout the world.

History

In the late 1920’s, René Moineau was pursuing the design of a new rotary compressor when he developed the concept for a series of helical gear pumps, which he referred to as a “capsulism”. One of these pumps took the form of what is now known as the progressing cavity (PC) pump, screw pump or Moineau pump.

After the Second World War, with the development of synthetic elastomers and adhesives, PC pumps were used effectively in applications involving petroleum-based fluids. In terms of downhole use, it wasn’t until the late 1970’s that a concerted effort was made to use PC pumps as a method of artificial lift for the petroleum industry.

Despite the fact that by 1979 approximately two hundred of the units were employed, given the limited capabilities of these pumps and alternative methods available, the use of these products in the US had ceased advancing.

In 1979, a group from Canada demonstrated the capability of the PC pump system to effectively produce heavy oil wells just south of Lloydminster, Alberta. Once the word of the success spread among the region’s heavy oil operators, the development and use of downhole oilfield progressing cavity pumping systems progressed quickly.

Advantages & Disadvantages

PC pumping systems have some unique characteristics that make them advantageous when compared to other artificial lift systems. One of the most important characteristics is their high efficiencies of 55 to 75%. Some additional advantages of PC pumping systems include:

• Ability to produce high viscosity fluids
• Ability to produce large concentrations of sand
• Ability to tolerate high percentages of free gas
• No valves or reciprocating parts to clog, gas lock or wear
• Good resistance to abrasion
• Low internal shear rates (limits fluid emulsification)
• Low capital and operating costs

PC pumping systems also have several disadvantages. The most prominent of these are limitations with respect to pump capacity, lift and elastomer compatibility with high aromatic fluids. Some additional disadvantages of PC pumping systems include:

• Limited production rates (max 500 m³/day or 3150 bbls/day)
• Limited lift (maximum of 3000 m or 9840 ft.)
• Limited temperature capability (maximum of 180°C or 350°F)
• Sensitivity to fluid environment
• Low volumetric efficiency when producing large amounts of gas
• Rod/tubing wear in some directional and horizontal wells
• Low capital and operating costs

These limitations are rapidly being overcome with the development of new products and improvements in materials and equipment design.

The above material is taken from the C-FER Technologies Progressing Cavity Pumping (PCP) Systems - Design, Operationg and Performance Optimization course notes.