Case History: Unique Method Using Hydraulic Workover Unit for Snubbing Operations Successfully Deploys Expandable Liner Hangers into Gas Storage Wells

摘要

When wells exhibit fluid-loss problems, lower completion scenarios that employ conventional liner hangers and inflatable annulus packers often exhibit problems as well. These scenarios can include 1), the occurrence of gas migration through the cement, and 2), liner-top, packer-seal failure. To prevent these problems from occurring in two gas storage wells, expandable liner hangers (ELH) that can provide gas-tight seals without requiring liner cementation were suggested. The ELHs have elastomeric elements bonded to the hanger body to provide anchoring and sealing capacity. As the hanger body is expanded, the elastomeric elements are compressed in the annular space, eliminating the casing annulus and providing liner-top pressure integrity. This scenario would provide a more effective solution for the problems experienced with conventional methods. The major challenges were how to deploy the two liner hangers into the two wells with a hydraulic work-over (HWO) unit and how to snub them into the hole with well pressure on the annulus. This paper will describe how a conventional rotary drilling rig was used to drill into the top of the well, and a snubbing unit used to drill into the reservoir section and then used to deploy the expandable liner hangers. To verify the adequacy of the deployment system design, a "Complete-the-Well-On-Paper" (CWOP) exercise was followed by a pre-job trial with the HWO unit. The ELHs were run through the unit to double check space out and potential for damage from the HWO slips with complete success. The next step was to run the equipment on location and into a live well. The case history will describe how the challenge to deploy and set the two expandable liner hangers with an HWO unit was met successfully.