During the completion of a brownfield carbonate development well in offshore Sarawak (Malaysia), a global energy company identified a potential risk in relation to their ability to obtain a good test at the liner seal stem. The 9-5/8” tie-back casing would potentially have to be pulled and re-run in the event of a leak.

Having previously purchased Welltec® Annular Barrier (WAB®) technology as a means of open hole cement assurance, the operator was already aware of the ISO 14310 V0 capabilities and versatility the WAB range could offer.

Following productive discussions between both parties, and further internal risk assessment, it was agreed that there was a high probability of a leak occurring.

Coupled with the fact that a WAB offers full bore inner diameter and would create no interference with the completion design, the decision was made to incorporate a 1214WAB into the tie-back completion for additional assurance, where it would be mounted on the 9-5/8” casing directly above the liner seal stem.

With Welltec now on board, a plan was formulated to re-run the 9-5/8” tie-back completion with a seal stem and a 1214 WAB to act as contingency in the event of a seal stem failure.

The completion was run, and after pressure testing, the originally identified risk came to the fore, as the seal stem was confirmed to be leaking. Therefore, the 1214 WAB was expanded by gradually increasing the setting pressure. Once reaching 1,500 psi, pressure was held for several minutes before being increased in increments of 1,500 psi with – each time with a further holding period – all the way up to 4,500 psi when WAB activation was complete: fully expanded and holding pressure without issue.

This operation was a complete success, with Welltec’s WAB solution offering unquestionable value, enabling the operator to progress with completion operations without the need to pull the liner tie-back and attempt a re-run.

The reliability of WAB setting and sealing first time every time, identifies its use as a reliable method for future operations where liner tie back assurance may be required, also avoiding potential downtime.

The seamless integration of a 1214 WAB into the completion is derived in part from its full bore ID, meaning no interference with completion design or objectives.