Rigid pipe decommissioning with DOF

As part of a North Sea field decommissioning programme, DOF Subsea was looking for an efficient solution to retrieve 4" coiled tubing from 115m water depths using an Offshore Supply Vessel from their fleet. The operational requirements included 20-tonne line pull and pivoting track for convenient product positioning.

MDL put forward the TTS-2/140 Series Tensioner, a 25Te 2-track unit featuring unlimited top track opening which facilitates efficient product acceptance and abandonment without compromising deck space, thanks to its compact footprint. MDL also provided a dedicated grillage for efficient sea-fastening onto the vessel to optimise mob and demob times in port.

In total, 12km of product was retrieved, including water injection, gas lift and production pipelines. Once on deck, the product was cut into 13-metre sections for efficient disposal onshore. David Stott, MDL Project Engineer commented: "Our tensioner fleet sets the market standard for pipe lay and retrieval safety, on top of the efficiency features that helped the client execute this scope ahead of schedule. This latest project adds to the tensioner’s varied track record which – among many flex-lay scopes - also includes replacement of rigid pipeline in an environmentally-protected area in the US West Coast and installation of a 25mm fibre optic cable offshore Mexico – all demonstrating this is a safe and convenient solution for oil and gas and renewable scopes alike."