Step Changes in West of Shetland Offshore Completion Design - First Two Online Multistage Fracs in Clair Deliver Operational Efficiency and Production Uplift

In the Greater Clair Area, the largest oil field in Europe, Hydraulic Fracturing (HF) has demonstrated its value in terms of delivering initial production uplift increases of 3 to 6 times with the first HF wells installed in Clair Phase 1, 2019, and Clair Ridge, 2022. Clair Ridge platform started production in 2018; however, some wells have not encountered sufficient natural fractures (NF) to replicate oil production rates from the initial appraisal wells, increasing the appetite for HF. SPE 216632 (Bird, 2023) documented successful production delivery from intervention-based HF in Clair, while highlighting these operations were inefficient on platforms not specifically designed to support HF operations. SPE 216632 expressed the case to move away from delivering HF in Clair as intense and complex well work campaigns to instead efficiently deliver HF "online" via drill pipe as part of the lower completion installation (additional operational details captured in SPE-226610 (van Loon, 2025). This paper will document the successful planning, design, and execution of the first two "online" HF completion operations delivered for Clair Ridge. 5 HF were executed in well B22 and 6 HF were executed in well B24, including record breaking efficiency for Clair with 4 treatments in 4 days. The process to optimise the completion design will be detailed through completion design and optimization, as well as B22 production outcomes and lessons learned implemented for B24. The paper will document the potential to incorporate sleeves designed for hydraulic fracturing in addition to multiple additional sleeves designed to provide proppant retention, sand control, and remote activated sleeves for intervention-less production start-up in differing reservoir environments (especially regarding rock strength). Providing such functionality currently increased the number of sleeves per zone (e.g., increasing from 8 to 32 sleeves in an 8 zone well). Developing a sleeve with all functionalities combined into a single sleeve was also assessed. The pros and cons of each approach will be presented outlining the risks associated, such as accidental sleeve shifting or proppant blockage around sand control sleeve annulus. B22 targeted Clair Unit III which has historically been completed with passive sand control standalone screens (SAS) which was a borderline decision. Ultimately, B22 was the first Unit III well to be completed without SAS, with HF providing additional mitigation for this decision. The process to install a robust sand-face completion will be documented. Details will be provided of solids production monitoring on startup through a temporary well clean-up package designed to remove solids and water and ensure smooth plant operations, including the use of Cutting Re-Injection (CRI) well to dispose of flow back fluids on the first well, with further optimisations made for the future. "Online" HF operations have been operationally and technically successful, thus predicted B22 production performance post-drill and actual production post HF will be reviewed, including installing a remote activated downhole choke inserted to control production from a NF zone at risk of water production. Analysis of B22 tracers to compare production splits on well start-up will also be presented.