Removal and recycling of H7
When AF was commissioned to remove and recycle platform H7 from a North Sea location exposed to extreme weather, entirely new methods were developed and patented to enable the efficient installation of lifting points on offshore structures.
About the project
Following thorough and extensive surveys and planning, 9,000 tonnes of steel from platform H7 were removed and transported ashore for source separation and recycling.
AF pioneered an entirely new method for dismantling structures in offshore environments where wind and snow posed significant challenges. Using a jack-up vessel, the platform was lifted piece by piece onto the ship, which remained firmly stabilised on six legs anchored to the seabed..
- Project type
- Decommissioning
- Project status
- Completed
- LocationVestlandet
- CustomerStatoil på vegne av Gassco
- Contract valueNOK 420 million
- Total weight of steel9000
New and innovative method
H7 operated in the German sector of the North Sea from 1977 and was connected to the Norpipe gas pipeline, which runs from Ekofisk to Germany. Under the Oslo–Paris Convention (OSPAR), Norway has committed to the responsible removal and recycling of platforms that are no longer in use. AF’s scope included the removal of steel, mechanical equipment, pipes, cables, concrete, marine growth and anodes.
A patented method was employed using wind turbine installation vessels equipped with six legs that can be jacked down to depths of up to 80 metres, ensuring a stable position on the seabed. The vessel was then elevated to the height of the platform deck, allowing the structure to be dismantled piece by piece and transported to AF Environmental Base at Vats for source separation and recycling. This same solution was later applied when AF removed B11, another compressor platform in the North Sea.
H7 was removed in 2013, within budget and on schedule, with zero lost-time injuries. The same AF team designed and executed the project, and knowledge transfer from H7 enabled AF to complete the removal of B11 in 39 fewer days—a reduction of 30% in time.
The B11 platform was removed in 2015 within budget and the stipulated time frame, and without any lost-time injuries.
