Subsea Concrete Mattress Recovery

(Champion: Fairfield Energy) – February 2019

When decommissioning an offshore facility, licensees have an obligation to remediate the site of subsea infrastructure. This typically requires the removal and recovery of many concrete mattresses that were placed there to construct, stabilise, and protect the subsea infrastructure within the platform and subsea development 500m safety zones. Propositions were sought to resolve the full scope of the UK Continental Shelf mattress removal challenges (i.e. from removal to shore). The focus was primarily on Northern and Central North Sea locations which have 13,745 mattresses with limited burial.