Isolation Barrier to Abandon Subsea Pipelines

When normal operation of a pipeline ceases, operators must adopt an appropriate abandonment process. The first step in the abandonment of a pipeline is decommissioning, which is to take it from its operating condition and render it clean and safe on the seabed.

Once decommissioned, pipelines can be recovered to the surface or in some cases left in situ on the seabed and buried by gravel. Pipelines that are severed and removed from the seabed require the bare pipe end to be capped and isolated.

STATS subsea Pipe End Plugs can be supplied as a temporary or permanent cap to terminate open pipe ends. They provide a robust isolation barrier to prevent seawater ingress or residual hydrocarbon escaping into the environment. Pipe End Plugs are supplied with securing wedge taper-lock grips to ensure security of the isolation plug in the pipeline at the specified pressures, and the large section elastomeric compression seal provide a leak-tight seal, even in corroded and pitted pipework.

10″ Subsea Pipe End Plug

These high-performance plugs are lightweight and simple to install by diver or ROV. Once inserted into the open pipe end, the plugs are activated and set in position by applying torque to the plug torque interface. To aid installation the Pipe End Plugs are supplied with a handling bracket and buoyancy as required.

ROV deployed Pipe End Plug modified to allow commissioning of a 22″ pipeline.

The Pipe End Plug lock and seal technology is based on the Tecno Plug® range of pressurised isolation tools which have an extensive track record covering a range of pipe sizes, pressures and mediums including, gas, crude oil and condensate.

42″ Abandonment Plug for a Middle East National Oil Company

STATS Group were approached by a national oil company in the middle east which had a requirement to isolate a 42” subsea pipeline dead leg housed within an oil storage tank, situated in the Persian Gulf. The operator had identified some irregular flow characteristics which made them suspect the integrity of this 42” dead leg. The operator was concerned that over time the problem would worsen, with the potential of water contamination of the oil export. Read how STATS engineered a solution to provide a secure isolation to be deployed subsea via divers into the 42” dead leg through an open flange entry point. Read how we did it in this case study.

Join STATS Group Live Webinar “Decommissioning Ageing Infrastructure: Abandoning or Re-routing Hydrocarbon Pipelines” on 15 November at 3PM London/10AM New York


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