The oil, gas and petrochemical industry infrastructure has an ongoing requirement for the isolation of pipelines and pipework systems while at operating pressure, to enable inspection or maintenance work to be carried out safely. STATS comprehensive Tecno Plug™ range provides fail-safe double block and bleed pipeline isolation tools for high pressure operations. These dual seal isolation plugs are available for remote, tethered, piggable or manual deployment and operation.
The dual seal configuration of the Tecno Plug™ provides an annulus void which can be pressure tested to verify both seals are leak tight before maintenance work is carried out, both seals are leak tested at 110% of the maximum potential isolation 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 bleed isolation. The large section elastomer seals are highly compatible with poor pipe surfaces and are customised to suit corrosion or ovality issues ensuring a leak tight seal even in ageing assets. A through-port is provided for downstream pressure monitoring or pressure application as required.
The Tecno Plug™ fail safe design uses differential pressure acting on the tool 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 isolation when the differential pressure is below the self-energisation threshold. Once the Tecno Plug™ is activated the hydraulic circuits are locked in by pilot operated check valves and manual isolation valves (tether controlled) or fail-safe solenoid valves (remote controlled). The check valve pilot lines can be separate lines controlled independently if required. The Taper lock-ring provides twice the required lock contact area giving 100% contingency. In the event that the hydraulic control system is compromised, the tool actuation mechanism will unset when differential pressure is equalised. This feature ensures pipeline integrity is maintained and the Tecno Plug™ is always recoverable upon job completion.
The remotely operated Tecno Plug™ system is a piggable, remote controlled, tetherless isolation tool. The remote control system provides a high degree of flexibility and eliminates the need for tethers or specially modified pig-trap doors. Through-wall communication is achieved using an extremely low frequency (ELF) radio control 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 and has undertaken a rigorous validation programme with ATEX rating to Ex P2 II 3 GT3. The external communication system is housed in an ATEX rated enclosure EE xd IIB T5.
DNV GL Type Approval:
STATS Tecno Plugs™ are fully certified by DNV GL to verify that the design criteria satisfies the requirements for Pipeline Isolation Plugs to provide dual seal and isolation in accordance with Offshore Standards; DNV-OS-F101 (Submarine Pipeline Systems) and recommended Practices; DNV-RP-F113 (Subsea Pipeline Repair) and in compliance with the following code; ASME BPVC Section VIII, Division 2.
Pigging Bypass Technology (Patent Pending)
STATS have developed a pigging bypass system for our isolation plugs (Patent pending) which allows two plugs to be pigged towards a blind centre. The technology was developed to facilitate the pipeline repair of unpiggable defects. This system allows a section of pipeline to be isolated where full bore pipeline access is unavailable due to a defect such as a pipeline buckle or dent. Each isolation plug is pigged from either end of the pipeline towards the defect to isolate the section and allow repair or replacement.
• De-commissioning (bleeding down) and re-commissioning (refilling and re-pressurising) of pipelines minimised or eliminated, saving time and reducing costs
• Production continued during pipeline maintenance or modifications
• No flaring of gas or displacement of pipeline inventory
• No emissions of gas or hydrocarbon vapour to the atmosphere during blow down
• No danger of accidentally flooding offshore pipelines during construction
• No need to dispose of hydrates, chemicals and contaminated water
• Isolates short sections of pipeline anywhere in the pipeline system
• Emergency preparedness and operational readiness
• Pipeline valve replacement / repair
• Riser replacement / repair
• Pressure testing and leak detection of risers / repaired pipelines
• Mid-line pipeline repair / tie-in
• Platform abandonment and bypass
• Pipeline diversion
|• Size range: 3" – 42" • Pressure range: up to 350 bar / 5075 psi • DNV GL Type Approval • Available as 3D / 5D compliant • Robust compact design, enables Tecno Plug™ to be set in short sections of pipeline. In many instances production can be continued during pipeline maintenance or modifications activities • Twin compression elastomer seals are highly effective even in pipelines with corrosion & ovality issues • High integrity isolation, taper lock-ring provides twice the required lock contact area i.e. 100% contingency • Annulus bleed between seals allows pressure to be vented to ambient creating a zero energy zone providing effective double block & bleed isolation • Fail-safe design feature; lock & seals energised by differential pressure; referred to as self-energisation • Self-energisation feature maintains safe isolation while differential pressure exists across the plug • Hydraulic system override releases the plug setting mechanism when pressure is equalised (Fail-safe passive unset feature) • Both seals fully energised by pressure – rubber pressure 1.1 – 1.4 times greater than pipeline pressure • Reverse pressure can be applied across the isolation plug to facilitate system leak testing • Outboard pressure monitoring options|