Innovative Helix On-Off Tool for Seamless Rod-Rotor Connection in Progressive Cavity Pumps with Tubing Internal Diameter Limitations

Objectives/Scope Progressive cavity pumps (PCPs) are widely used in heavy oil applications, but well configurations, such as slim casing diameters, can lead to excessive rod-tubing contact, resulting in rod failure and tubing wear. Polycore coatings minimize friction but reduce tubing clearance even more, making it difficult to run larger-diameter rotors. To address this, PCP rotors are preinstalled inside the stator downhole, requiring an effective way to connect the rod string to the rotor using on-off tools. However, standard on-off tools introduce additional challenges by limiting fluid flow due to their large size. This paper focuses on developing and implementing a new, smaller-diameter on-off tool to improve clearance, optimize flow, and enhance system reliability for high-flow PCP applications. Revised Methods, Procedures, Process In Argentina, typical wells use 2 ⅞-in. tubing (2.442-in. inner diameter [ID]), which is further reduced to 2.28 in. after applying Polycore coating. In these scenarios, rotors must be preinstalled inside the stator downhole since they cannot pass through the coated tubing. The new on-off tool consists of two components: a shroud, connected to the rotor's top, and a mandrel, which is attached to the rod string. During installation, the mandrel locks inside the shroud, ensuring a secure connection between the rod string and the preinstalled rotor. Unlike standard tools with outer diameters (ODs) near the tubing ID, which restrict flow, the new tool features a smaller diameter (1.96 in.) and a helical design to enhance fluid displacement. Revised Results, Observations, Conclusions The new Helix on-off tool, with a major OD of 1.96 in., was successfully implemented in the field. Finite element analysis (FEA) confirmed the mandrel can withstand stress concentrations of 990 MPa (90% of its elastic limit) and handle 1,250 lbf/ft of torque under static loads during continuous operation. Field trials reported reduced torque during operation and no issues with unseating or misalignment, confirming the tool's effectiveness in establishing and maintaining secure connections. Revised Novel/Additive Information The helix on-off tool overcomes traditional clearance limitations by enabling the connection of the rod string to a rotor preinstalled inside the stator. Its smaller diameter and helical shape optimize fluid flow around the tool, reducing pressure losses and preventing overpressure at the pump discharge. These improvements reduce the likelihood of system uncoupling and extend the pump's service life. This solution offers a reliable method for deploying high-flow PCPs in coated tubing environments, enhancing operational efficiency and setting a new standard for PCP installations in tight-clearance conditions.