The operation made it possible for the operator to safely replace a faulty shut down valve (SDV) located above the riser on a platform situated off the coast of Louisiana, United States. The riser connects to a key gas pipeline system.

To ensure that the SDV would be safely replaced, TDW was retained to provide a field-proven solution. TDW performed a ‘double-block’ isolation against the gas pressure in the designated riser using two SmartPlug isolation plug modules linked together.

Following extensive hazard identification exercises and equipment testing, TDW launched the SmartPlug modules from the platform, using the SmartTrack system to monitor the pressure and track them. The modules were pigged in for 24 m, travelling under a flow rate of 30–40 gallons per minute, at approximately 131 bar, until reaching their destination near the top of the riser.

TDW set the downstream SmartPlug module and bled the topside pressure to approximately half of the riser pressure. With data confirming the integrity of the downstream seal, TDW technicians set the upstream SmartPlug module and monitored the pressure between modules until they were confident that the module was holding pressure and that the SDV could be safely replaced. The SmartPlug modules remained in the riser for 12 days while the operator replaced the SDV. Throughout this period, TDW took hourly pressure readings of the isolated section using SmartTrack ‘through pipe wall’ communications technology, which relies on extremely low-frequency, electromagnetic waves to transmit isolation integrity data to a transceiver, which in turn relays it to a control centre.

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Utilising the double-block isolation created by the SmartPlug modules, the crew performed a leak test on the repaired section. After confirming the integrity of the newly installed valve, pipeline pressure was equalised and the SmartPlug modules un-set and retrieved, allowing normal production to resume.