Subsea Riser Bases

Decommissioning Case Study

Recycling Rate:
Maersk Oil
Gryphon Field, Northern North Sea
Montrose Port, Angus
Downsizing and recycling of subsea riser bases
Project Summary

Four subsea riser bases from the Gryphon Field were brought onshore at Montrose Port for decommissioning, which involved the removal of concrete, size reduction and material recycling.

The riser bases consisted of a heavy steel sectional base frame, onto which steel struts were fitted that supported the ends of the flexible risers. Each riser base was filled with a very dense concrete. After the steel struts and pipe ends were removed from the base frames, the concrete was broken out of the steel sections using excavators fitted with concrete breaker heads.

The steel sections were cut into transportable lengths and all materials were transported offsite for full processing and recycling. Our expert team carried out the work at the Angus port over a five-day period, and recycling rates of 98.92% were achieved.

Maersk’s Project Safety and Environmental team worked closely with all of the relevant parties involved in daily site inspections and safety conversations, resulting in an incident-free operation.

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We are the largest metal recycler and exporter of processed metal in North and North-East Scotland and an experienced member of the decommissioning supply chain. With current strategically located licensed facilities in Aberdeen, Shetland, Evanton and Montrose, and the addition of our new quayside facility in Dundee opening in 2020 bringing our combined annual licensed tonnage to 360,000 tonnes, we are your decommissioning partner of choice.