Field Deployment of a Rigless, Cable Deployed ESP Using a Vertical Wellhead

摘要

Electric submersible pumps (ESPs) are a widely used artificial lift technology. Conventional ESP systems provide power through a cable banded to the outside of the tubing. These systems have drawbacks in terms of installation speed and efficiency. To overcome these obstacles, a novel cable deployed (CD) ESP system, developed for use in a high hydrogen sulfide (H2S) production environment, was formulated as a future solution. This article focuses on the challenges, results and lessons learned from the first field deployment in the world of a rigless, high H2S CDESP system. A metal-jacketed power cable was a key enabler to developing the CDESP system. The metal-jacketed power cable delivers the best protection against a H2S attack and provides a smooth outside diameter that can be gripped on and sealed. The cable has been tested to withstand H2S levels up to 15% and chloride levels in excess of 150,000 ppm with an expected service life in excess of 10 years. To overcome well control concerns, a cable hanger spool was developed enabling the ESP cable to be terminated below the master valve. In addition to the surface termination of the cable, the cable hanger spool provides hang-off and production flow through capabilities. The field deployment of the CDESP system, using a specialized inverted ESP, required the close integration of several equipment and service providers during the development of the equipment and procedures to ensure success in the installation of the system. The system's initial deployment was in a benign onshore well that offered ample workspace for the various service providers to learn the unique aspects of this rigless deployment. Of particular importance, the interface for the service providers at the surface cable termination was critical to the successful installation. For this trial test, the well completion was changed from 41/2 tubing to 7" tubing to accommodate the cable deployed 562 series ESP. Lessons learned from this field trial will be incorporated into future trials of the CDESP technology. The goal of these future trials will be to deploy the technology in offshore H2S wells where high rig costs can be significantly reduced through the use of a lower cost barge coupled with the increased speed, efficiency, and ease of CDESP deployment.