STATS Group, has completed an isolation project on behalf of Interconnector UK Ltd to facilitate valve remedial works at the Zeebrugge Onshore Gas Terminal in Belgium.
Interconnector required a double block isolation to provide safe worksite conditions to allow change out of a 40” pig trap valve during a planned shutdown.
To minimise production impact, the pipeline landfall valve, which is 1km away from the pig trap valve, was closed to provide the primary isolation against 80 Barg of gas pressure.
STATS utilised a 40” Tethered Tecno Plug to provide a secondary isolation. Prior to deployment a client witnessed factory acceptance test (FAT) was conducted in a purpose-built test fixture.
The Tecno Plug™ was deployed to location past the pig trap valves and barred tee. The 1km of pipeline between the Tecno Plug and the pig trap valve was opened to vent by utilising the valve bypass arrangement with a 6” open vent.
The Tecno Plug™ was set at location using a hydraulic system via the umbilical and an annulus test was performed to verify the integrity of the primary and secondary seals. Both seals were independently tested and monitored for 12 hours and once the verification period was completed, the isolation certificate was issued. With the Tecno Plug™ providing a verified isolation the valve was rigged away.
On completion of the valve maintenance, further umbilical management was carried out to allow the valve to be repositioned. After the valve was replaced and integrity confirmed, the Tecno Plug™ was unset and retrieved back into the pig trap for demobilisation, allowing the pipeline to be re-pressurised and normal operations to continue.
Isolation Services Manager, Steven Byers, said: “This successful isolation work scope was carried out in a safe, efficient and professional manner throughout, allowing Interconnector to maintain its schedule and complete all necessary maintenance within the proposed shutdown window. This demonstrates the capabilities of our technology and we hope will lead to similar projects as we expand our presence in the European onshore sector.”