WSO With Annular Isolation And HEX Bridge Plug In A Deviated Subsea Gravel Pack Completion
An offshore operator in Norway faced a critical rise in water cut that threatened to kill a subsea gas producer prematurely. The complex deviated open-hole gravel pack required a dual-layer solution: achieving zonal isolation both inside the completion and outside in the annulus to stop water ingress.
Year
Region
Water Flow
Challenge
An offshore operator in Norway was experiencing increasing water cut in a gas producer that risked killing the well prematurely and halting production. The operator established a Water Shut Off (WSO) objective to provide zonal isolation both outside and inside a deviated open-hole gravel pack completion, preventing water ingress. The scope involved establishing annular isolation within the gravel pack using wireline-conveyed epoxy-based sealant, followed by deployment of a retrievable high-expansion bridge plug inside the completion.
Solution
Multiple Interwell intervention solutions were mobilised to the wellsite to maintain flexibility in isolating water entry points confirmed through production logging and visual diagnostic tools.
→ Anchored Production Straddle (APS)
→ High Expansion (HEX) Retrievable Bridge Plug (RBP)
→ Annular Isolation – Cannseal ZonalSeal
The client also used topside data interpretation to guide the final selection of adding zonal isolation to stop water ingress from a lower zone. This was achieved by injecting annular isolation into the gravel pack, combined with the installation of a retrievable bridge plug inside the screen. To mitigate the identified risk of exceeding formation fracture pressure during annular isolation, onshore injection testing was conducted using a gravel pack test cell. Pressure-drop analysis from testing established a controlled epoxy injection rate capable of penetrating the gravel matrix to form a circumferential isolation over a short length, without damaging the formation.
Accurate depth correlation ensured epoxy placement within the annulus across a short blank section between the 6-5/8" screens and 9-1/2" open hole, preventing returns through screen base pipe holes. Injection pressure and volume were monitored in real time, with strict volume control maintained throughout the operation. 10L of epoxy achieved a calculated 1m annular isolation outside approximately 3m of available blank pipe length. At a controlled rate of 0.2L/min, injection pressure increased gradually, closely matching pre-job testing, indicating that controlled gravel pack penetration was achieved without formation damage. A high-expansion retrievable bridge plug was then set inside the screens to complete the isolation of production from below.
Value Created
Although one of the highest-quality sands was isolated, the well exhibited an increased Relative Productivity Index (PI). Improved contribution from previously weaker zones was observed following the elimination of liquid loading from the high-velocity fluid flow.
The results demonstrate that this rigless method is an effective and practical solution for managing water production in late-life gas wells.
→ The well was returned to production and flowed water-free
→ The well’s productive life was extended
→ Overall gas production increased by 10–20%
Key Benefits
- Precisely placed solution with immediate impact
- Extend and protect late-life gas producers
- Uplift in gas production
- Increased Relative Productivity Index
