Mattress recovery is the lifting of concrete mattresses off the seabed at the end of field life. These rope-linked concrete blocks are laid over subsea pipelines, cables, and umbilicals to add weight and shield them from dropped objects and snagging, and were never designed to be removed.
On the UK Continental Shelf, decommissioning is governed by the Petroleum Act 1998 and regulated by the Offshore Petroleum Regulator for Environment and Decommissioning (OPRED), under which installed mattresses must be removed unless an operator can demonstrate that recovery cannot be completed safely and efficiently. Offshore Energies UK forecasts the removal of 16,661 concrete mattresses between 2021 and 2030. Unique Group’s Ren Mattress Recovery Tool is available for rental and uses a water-hydraulic gripping mechanism, deployed by ROV, diver, or deck crane.
Applications include decommissioning, rerouting, recovery for repair or reinstatement, pipeline and cable access, and site clearance.