The dual seal configuration of the pipeline isolation plug provides an annulus void between the seals which can be pressure tested to verify both seals are leak-tight before maintenance work is carried out. Both seals are leak tested with full pipeline pressure. Once the seal integrity has been proved the annulus is then vented to ambient to create a zero-energy zone, providing effective double block and monitored pipeline isolation. The large section elastomer seals are highly compatible with poor pipe surfaces and are engineered to suit corrosion or ovality issues ensuring a leak-tight seal even in ageing assets. The isolation plug has the ability to monitor the isolated pipeline pressure, this is achieved via a dual sealed pressure impulse line and ensures there is no leak path through the tool. If required, pressure application through the isolation plug is attained by adding an additional module containing a second equalisation valve. Pipeline isolation safety is ensured as two separately controlled valves need to be functioned to allow pressure communication through the Tecno Plug.
The Tecno Plug fail-safe design uses differential pressure acting on the plug to energise the locks and seals, this is referred to as self-energisation. When the isolation plug is self-energised the isolation is maintained independent of the control system, it is however backed up by the hydraulic control system which maintains the pipeline isolation when the differential pressure is below the self-energisation threshold. Once the isolation plug is activated the hydraulic circuits are locked in by fail-safe solenoid valves. In the event that the control system is compromised, the tool actuation mechanism will unset when differential pressure is equalised. This feature ensures pipeline integrity is maintained and the isolation plug is always recoverable upon job completion.
Through-wall communication is achieved using an extremely low frequency (ELF) inductive system for reliable tracking and accurate positioning of the Tecno Plug. An onboard hydraulic power pack provides the necessary actuation and control functions for the tool. The remote control module provides a robust system for safety critical activities. Remote Control Modules can be made available for use in a Zone 2, Potentially Explosive environment. The communication antenna and field cable are available for use in a Zone 1, potentially explosive environment.
Specification
Size
10” – 56”
Pressure
200 bar / 2900 psi
Verification
DNV Type Approval
Communication
3000m Depth Rating
Related Resources
Subsea Repair Scenarios of Damaged Pipelines
36” remote tecno plug | forties pipeline system, north sea, uk
28" Subsea Pipeline Isolation & Repair, Yacheng Pipeline, China
Unconventional Applications of Pipeline Isolation Plugs
