Experience With Metal PCPs in a Cuban Heavy-Oil Field

Abstract

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 120645, "Field- Implementation Experience With Metal- PCP Technology in Cuban Heavy-Oil Fields," by E. Guerra, SPE, and A. Sanchez, SPE, Sherritt International Oil and Gas, and C. Matthews, SPE, C-FER Technologies, originally prepared for the 2009 SPE Production and Operations Symposium, Oklahoma City, Oklahoma, 4-8 April. The paper has not been peer reviewed. Progressing-cavity pumps (PCPs) have proved to be a successful and reliable artificial-lift system for production of heavy oil over the past few decades. The application of PCP technology for production of oil wells continues to expand rapidly because of ongoing advances in versatility, lift capacity, durability, and economy. As a result, the application envelope for PCP systems has grown substantially to the point where these systems now compete successfully in many areas that were traditionally reserved for rod- and electrical-submersible-pump technologies. Introduction PCPs have found numerous applications in many industries as an efficient means to transfer, transport, and/or lift fluids of a diverse nature. The use of PCPs as an artificial-lift method for oil wells has gained increasing acceptance since their first commercial use in heavy-oil applications in the 1980s, and they have now become the preferred lift method in numerous oilfield developments worldwide. PCP Systems A typical PCP consists of two basic components: the first is called the stator—it is typically run on the end of the production-tubing string and remains stationary during operation; the second is called the rotor—it is run on the end of a sucker-rod string and rotates within the fixed stator when in operation. The elongated steel rotor is machined with a circular cross section and a uniform helix with a prescribed eccentricity and pitch length. Rotors are normally chrome coated to reduce friction and improve wear resistance in service. The stator cavity takes the form of a double internal helix with a pitch length that is double that of the rotor—with the rotor installed, this configuration creates two series of parallel cavities within the pump that are filled by produced fluid. As the rotor spins within the stator through the application of torque to the rod string at surface, wellbore fluid is drawn into the pump and is displaced from the intake through the cavities along the stator to the discharge where it exits at high pressure into the production-tubing string.