Enhancing Well Reliability and Productivity: Implementing the 7-Inch Annulus Casing Packer Tieback System for 9-5/8-Inch Casing Remedial and Gas Lifting Completion in the UAE

Abstract

The application of the 7-inch Annulus Casing Packer (ACP) Tieback system in ADNOC Onshore' s 9-5/8-inch casing remedial and gas-lift completion programs delivers notable operational and economic benefits. Certified to ISO 14998 V0 standards, which qualifies packer seals for zero gas migration, the ACP offers a superior alternative to conventional tieback methods, consistently shortening project schedules by 5–7 days. This performance is driven by its integrated design features, including a hydraulically actuated Stage Tool for annular access, a V0-rated packer, and a Landing Collar with a non-shearable ball seat. The non-shearable ball seat design removes the need for temporary isolation means below the top of the liner (TOL), eliminating the risk of cement slumping or falling into the reservoir instead of filling the annulus between the 9-5/8-inch casing and 7-inch Tieback casing.

This approach focuses on deploying the ACP Tieback system in combination with optimized annular sealing strategies, supported by mechanical integrity simulations to assess long-term performance under pressure and temperature cycling. Tieback installation in remedial scenarios—particularly where gas-lift mandrels are incorporated—presents unique challenges, including the requirement for accurate assessment of outer casing condition, burst pressure capacity, and selection of an appropriate top of seal. The methodology also incorporates displacement sequencing and interface management to ensure clean, uncontaminated sealing surfaces, thereby enhancing reliability.

Field implementation in more than 90 ADNOC Onshore wells has demonstrated consistent time savings, improved well integrity, and the elimination of multiple ancillary tools or interventions. This advancement contributes to operational efficiency, cost reduction, and sustainability objectives by minimizing rig time and equipment usage. The paper presents this solution as a proven, field-ready enhancement to completion and remedial operations, offering engineers a practical pathway to achieve superior performance with reduced complexity.