High Expansion Multi-Run APS: A Custom Solution for Deepwater WSO

Interwell was tasked with developing an extended-length Water Shut Off (WSO) solution to achieve isolation across the upper zone of two subsea OHGP wells, which would directly contribute to the commercial viability of the subsea campaign. Both wells required a custom High Expansion (HEX) Anchored Production Straddle (APS) solution with the capability of passing through a 4.25” restriction and setting in 6-5/8”, 24# and 28# tubing, while also being compatible with deviations of up to 89°. Due to uncertainties in conveyance methods, the system had to be suitable for deployment on both E-Line and Coiled Tubing.

To meet these requirements, a custom 400-663 HEX APS (4.00” O.D) was developed and qualified to ISO14310 V0. The testing ensured the equipment was suitable for the well pressures and temperatures provided, while also confirming a suitable hang-off weight to account for the maximum tubing weight of a 2-run system. Due to the high deviation, there were concerns that the stinger assembly would be lying on the low side and have difficulty latching into the corresponding latch assembly. To address this, a custom tapered nose was designed to improve access into the latch while maintaining sufficient flow area.

 Interwell’s flexible stinger and latch system allows the number of runs needed to be adjusted on-site, providing greater operational flexibility for the client and suitability for both E-line and Coiled Tubing deployments.

In order to offer the use of back-up systems across various future wells, a common HEX APS mandrel was developed, with interchangeable conversion kits to suit both 24# and 28# tubing weights:

1st Well:

• APS: 400-663 24# HEX MR
• → Planned Isolation: 95m (actual: 99m between elements)
• Challenge: A 15m gap between Upper Completion and Lower Completion caused issues entering the LC

2nd Well:

• APS: 400-663 28# HEX MR
• Planned Isolation: 201m (actual: 201m between elements)

The modular systems allowed for the Bottom Hole Assembly (BHA) lengths to be adjusted on-site, aiding deployment and leading to an efficient operation, with the work scope for the 1st and the 2nd wells completed within 10 and 5 days respectively, and each well returned to production within days of completion.

 All operations were conducted with zero LTIs.

 “This straddle was not only one of the longest straddle runs ever achieved globally, but also a pioneering operation for us, completed aboard the Drillship. This was no small task. It stands as a major milestone in our operations, and we are immensely proud of the team’s role in this achievement.” - Client Subsea and Completions Supervisor.