Elevating Workover Rig Intervention for Well Integrity Using Instrumented Coiled Tubing and Through-Tubing Inflatable and Retrievable Packer: A South Kuwait Field Application

Abstract This paper delineates a groundbreaking intervention in South Kuwait Field, where the integrity of a well for workover rig operations was successfully reinstated by harnessing instrumented coiled tubing (CT) combined with a through-tubing inflatable and retrievable packer (TTIRP). In the described scenario, mechanical obstructions at the Christmas tree tubing hanger posed significant challenges for the conventional installation of the blowout preventer (BOP) on the workover rig. This necessitated the adoption of a tailored approach to establish the essential pressure barriers for well intervention. The implemented intervention strategy utilized instrumented CT for the dual purposes of well killing and temporary suspension. The real-time downhole telemetry of the CT played a crucial role in guaranteeing the precise deployment and activation of the TTIRP within the production tubing. Following a comprehensive pressure test of the packer from both ends, the CT was removed. Subsequently, a sand plug and an acid-soluble cement plug were strategically positioned above the TTIRP. After verifying the integrity of the cement plug, the workover rig was engaged to fit the BOP. The instrumented CT was then redeployed into the well to dissolve the cement plug, remove the sand, and extricate the TTIRP back to the surface. The targeted well for this advanced intervention workflow was characterized by a maximum potential wellhead pressure of about 1,500 psi and a plug-back true depth (PBTD) of 4,000 ft. The well's completion involved 3 1/2-in. production tubing installed up to approximately 3,500 ft measured depth (MD) and 8 5/8-in. casing extending to the PBTD. Prior to the initial CT operation, an e-line through-tubing puncher was utilized in the production tubing to facilitate the circulation of the killing fluid. The TTIRP's setting depth was meticulously prepared using the instrumented CT and a high-pressure rotary jetting tool, achieving a shut-in wellhead pressure close to zero psi. The outcomes of this cutting-edge intervention workflow were remarkable, conserving an estimated 195,000 barrels of deferred production as the well had been shut-in for a minimum duration of ten months. The insights and experiences accrued from this case study are poised to act as valuable guidelines for operators in the Middle East faced with comparable well challenges.