Liberty Industrial blasts 11,500-tonne offshore platform

The oil and gas platform was originally built in 1976 as a drilling rig of Aker H-3 design, and in 1991 it was converted into a floating production facility.

Before its retirement in 2021, the facility was operational in the UK North Sea, located about 150 km north-east of the Shetland Islands and 12 km north of the Thistle Field, at a water depth of 170 m.

Liberty Industrial was contracted to decommission the structure by Northern Offshore UK in 2023. It carried out the recent blasting on June 13 of this year, utilising what it describes as a “first of its kind approach for such an asset”.

Weighing approximately 11,500 tonnes, Liberty Industrial determined that the safest way to carry out the works would be to bring the topside to a reduced height by means of explosive techniques.

(PHOTO: Liberty Industrial)

The demolition specialist leveraged international experts to develop the explosive methodologies as part of a ten-month programme to decontaminate, demolish, recycle and dispose of the offshore platform in a dry dock.

The sophisticated demolition design was developed in collaboration with expert subcontractors that included Precision Demolition Company (PDC) for explosives engineering services and design, and Applied Science International (ASI) for modelling of structural failure modes.

The methodology utilised explosive charges placed in 38 locations on the platform. The blasting triggered a controlled collapse of the platform that reduced its height, so that further dismantling and recycling works would be carried out. 

Reported to be “one of the largest single use of explosives at a demolition site in Europe at the time of the project”, Liberty Industrial said the “process ensured the NP fell in a precisely controlled, symmetrical method towards the back wall of the dry dock onto itself”.

Martin Hewitt, Liberty Industrial’s UK General Manager, said: “As the second major contract for Liberty Industrial in the UK, we overcame challenges faced due to the uniqueness of the dry dock approach, and its location in a remote region of Scotland.

“By sourcing experienced, qualified labour from Scotland and North East England, combined with project management expertise from Australia we ensured the safest and most innovative outcome possible.” 

(PHOTO: Liberty Industrial)

Martin added: “We are extremely pleased with our ability to leverage our strengths, with PDC and ASI, to successfully deliver such a milestone event for the decommissioning industry in the UK. It demonstrates our capabilities and our growing position in the UK market.”

Prior to the blasting, Liberty Industrial removed all hazardous materials, such as asbestos, NORM, diesel/oils, electrical systems, contained water, energized systems, marine growth, and accommodation module components, from the structure. 

Ongoing decommissioning and demolition work on the platform is being carried out at Kishorn Port Limited’s dry dock facility, which is situated within north-west Scotland.

The dry dock provides a controlled and contained environment ideally suited to undertaking the successful demolition of the Northern Producer.

“The decommissioning of the asset is set to support both the local and international circular economies, with an expected 97-98% recycling rate, including recovered ferrous metals, machinery and marine growth, which was repurposed as fertiliser in the local farming community,” said Liberty Industrial.

“Other various electronic hardware and components were recycled, further promoting sustainability and environmental responsibility for the industry.”

VIDEO: Recycling begins on “largest demolition project in Australia’s history” Remediation works to recover 142,000 t of scrap metal and 300,000 t of concrete from Gove Refinery