TDW used its remote-controlled SmartPlug to isolate pressure in specific sections of pipelines and risers so that repairs or interventions can be carried out safely.

Initially in 2012, TDW was required to isolate a 16-inch gas riser connected to a major subsea gas pipeline network in order to replace a valve. Therefore, the company carried out engineering work, assembled the pressure isolation tool and completed all factory acceptance testing (FAT) in mid-2012. Plans changed when the operator decided to postpone replacement of the single valve so that three additional valves could be installed, and a launcher extension added to facilitate inline inspection tool runs. In early 2014, TDW was advised that the planned isolation would commence in May 2014.

In order to commence operations on time, TDW re-verified the project engineering, performed additional communication and pull tests, and executed a new in-depth FAT. In addition, a comprehensive range of risk and peer reviews internally and with the client were carried out. Working in cooperation with the operator’s team, 3,500 hours were invested in preparing for the isolation.

The SmartPlug tool was pigged for 18.28 metres into the riser toward its set location offshore. TDW used its remote-controlled SmartTrack tracking and monitoring system to track the tool’s progress, control its speed, and monitor conditions in real-time. Upon reaching its set location, the tool was set into position. The same day, the isolation was confirmed and certified. The riser was securely isolated against a pressure of 1,711 psi for 79 days.

During the 11-week period, the three valves were replaced and the launcher extension installed, which would help enhance future inline inspections of the line. Upon completion of the project, the SmartPlug tool was retrieved intact.

Bjørn-Olav Gilje, project manager for TDW, said, “Because we worked in such close cooperation with this strategic partner, we developed an extremely high level of communication and understanding, which was essential to making the isolation a first-time run success.

“As a result, the complex valve upgrade project and launcher extension installation were completed with minimal downtime, without disrupting production or supply to millions living on the Gulf Coast. A continuous flow through the multiple downstream connections was maintained throughout the duration of the project. The fact that it was achieved safely, without affecting the surrounding environment in any way makes it all the more satisfying.”

Source : OIL REVIEW AFRICA