Wireline packer remediation using novel bismuth technology

Abstract

Prior to the execution of this project, there were limited options for repairing a failed production packer. Conventional oilfield practice would default to a well workover to replace the failed component. In an offshore environment, this approach not only carries significant capital cost, but also material risk and health, safety and environment exposure associated with the large operational footprint and time requirement of the operation. An innovative solution was developed to remediate the failed packer without a workover while simultaneously significantly reducing cost and risk. A new packer was formed by melting a bismuth alloy plug into the annulus using wireline equipment, eliminating the requirement for a workover rig. Bismuth alloy pellets were deposited onto the packer via precisely drilled holes in the tubing before being melted into an annular plug, forming a gas-tight metal-to-metal seal. As this was an industry first, prototype testing of the annular bismuth plug was undertaken to demonstrate concept feasibility. After a series of iterative testing a viable concept was achieved, and the prototype was taken forward to qualification. The annular plug was qualified to industry standard ISO 14310 V0 for the well’s operating conditions which included both pressure differential and axial loads. After the bismuth annular plug was qualified, the deployment method for the bismuth pellets was optimised to ensure they reached targeted location without compromising well integrity. After 2 years of design, the industry-first wireline intervention was successfully executed in 2021 and the well was returned to production.