The isolation project utilised two remote-controlled 30 inch SmartPlug dual-module pressure-isolation tools to isolate approximately 72 km of pipeline.

“The SmartPlug isolation tool is certified to ‘Safety Class High’ in accordance with OS-F101 for Submarine Pipeline Systems and is uniquely suited for use in connection with diving operations,” says TDW Project Manager Bjørn-Olav Gilje.

Each tool was composed of two plug modules and two pigging modules. One of the tools provided double block isolation on the high pressure side of the tie-in location. The first module on the second tool provided a hydraulic locked barrier of the high pressure side for the divers installing the wye. The second module on the second tool was used to perform a leak test to verify integrity of the new wye after installation.

Following launch, TDW technicians aboard the dive-support vessel Norman Commander used the remotely-operated SmartTrack tracking and pressure monitoring system to continuously monitor the locations of the SmartPlug tools as they travelled to their subsea set destinations. The SmartTrack system uses two-way, through-wall, electromagnetic communication between a transponder and a receiver to track tool progress. Once the tools were set, the isolation period was approximately two and a half weeks.

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“TDW worked with the client and its contractors over several months to ensure that associated risks were evaluated and mitigated,” Mr Gilje adds. “This thorough up-front planning resulted in a successful tie-in operation for our client. Working together achieved a result that we are proud to have been part of.”