Subsea Mattress Recovery for CCS Infrastructure

This case study details the subsea mattress recovery project conducted by Ashtead Technology for Boskalis Subsea Services, aimed at supporting a carbon capture and storage (CCS) infrastructure campaign in the UKCS. The project involved the recovery of subsea mattresses from depleted hydrocarbon fields, focusing on repurposing existing oil and gas infrastructure for CO2 transport and storage. The challenge was to perform this operation safely and efficiently under challenging seabed conditions with minimal reliance on remotely operated vehicles (ROVs). The solution deployed was the Mattress Recovery Tool (MRT), which facilitated the safe retrieval of mattresses using a vessel crane. The MRT's design included integrated thruster control software, enabling self-orientation during recovery and reducing ROV assistance. The project successfully recovered various mattress sizes without tool downtime, demonstrating the MRT's efficiency and reliability, while also contributing to low-carbon energy objectives.