Once the decommissioning of the topsides, substructures, pipelines and associated subsea infrastructure have been completed, operators are required to ensure that the seabed is made safe for third-party users of the sea. This involves the removal of any debris remaining around the facility as agreed within the Decommissioning Programme.
After completing the offshore decommissioning works, an independent organisation is required to complete a seabed verification trial. These usually entail a fishing vessel undertaking a trawl trial over the site from numerous approaches, using various representative fishing equipment. However, verification could also be conducted with survey equipment which can detect and analyse any features remaining on the seabed.
Within one year of a post-decommissioning survey, a Decommissioning Programme Close Out Report is required to be submitted for regulatory approval. This report is required to satisfy OPRED that the approved programme has been carried out and describe any scope modifications required during execution. Close Out Reports are a key reference where learnings from decommissioning projects are shared.