About the project
We continue to demonstrate our position as a trusted provider of marine environmental services to the UK offshore oil and gas decommissioning sector, delivering a comprehensive environmental survey campaign across multiple decommissioned assets in the Southern North Sea (SNS) during early 2025.
Commissioned directly by the operator, this work marked a significant evolution in our longstanding involvement in North Sea decommissioning, building on prior campaigns delivered via contractors. For this latest scope, we contracted and mobilised the newly built survey vessel MJM Enterprise, a Category 1-coded vessel fully equipped for 24-hour operations and with DP capability. The mobilisation from Hartlepool enabled efficient delivery of the campaign under tight timescales and challenging weather conditions.
Comprehensive scope for a changing industry
With decommissioning now a central pillar of the UK’s offshore energy strategy, our role encompassed the full spectrum of environmental survey services required to meet regulatory and ecological obligations. Surveys focused on three decommissioned fields located within UKCS blocks 49 and 53. Each site was assessed in line with Oil and Gas UK (OGUK) Seabed Survey Guidelines and relevant environmental standards.
The programme covered:
- Drop-Down Camera (DDC) surveys using Ocean Ecology’s in-house clear liquid optical chamber (CLOC) HD video and stills systems to characterise seabed habitats and inform subsequent sampling.
- Sediment grab sampling using dual 0.1 m² Van Veen grabs, with samples analysed in-house for macrobenthic communities, physico-chemical parameters, and environmental DNA (eDNA) for biodiversity monitoring.
These methods enabled thorough assessments of seabed condition, identification of any residual contamination, and documentation of Annex I and V habitats and species, OSPAR features, and Marine Protected Area (MPA) designations including Sabellaria spinulosa reefs.
Why eDNA is a potential game-changer for decommissioning
The integration of eDNA analysis represents a significant evolution in marine monitoring. By detecting trace genetic material left behind by organisms in sediments, eDNA provides a sensitive, non-invasive method for assessing biodiversity—even for cryptic, rare, or transient species that might be missed by traditional survey techniques.
In the context of decommissioning, eDNA allows for:
- Enhanced detection of conservation interest species
- Improved understanding of habitat recovery trajectories
- Early warning for Invasive Non-Native Species (INNS)
- Supplementary data to support evidence-based regulatory submissions
This innovative approach is now increasingly recognised by regulators and stakeholders as a valuable complement to conventional benthic and contaminant monitoring, particularly in complex or data-poor marine environments.
Strategic insights to close out decommissioning
The surveys delivered essential data for confirming post-decommissioning environmental baselines and assessing recovery of previously disturbed areas. Key outcomes included:
- Mapping of residual seabed debris and free-spanning infrastructure.
- Temporal comparison with historic data to assess changes in seabed character.
- Confirmation of biodiversity recovery and absence of Invasive Non-Native Species (INNS).
- Evidence to support the removal of 500 m safety zones and enable over-trawl clearance.
Surveys were undertaken across wellhead sites, pipelines, and umbilicals. In total, more than 70 stations were sampled across multiple fields, with DDC imagery and replicate grab samples collected and processed in our NMBAQC-participating laboratories.
End-to-end capability for the energy transition
This successful campaign underscores our ability to act as a one-stop shop for offshore environmental assessments – providing expert staff, proven technology, in-house laboratory services, and the capacity to contract and manage full-scope surveys aboard fit-for-purpose vessels.
As the UK’s offshore oil and gas industry transitions into a new era of environmental accountability, we remain committed to delivering robust, regulator-ready data that supports the safe and sustainable closure of legacy energy infrastructure.
Supporting a sustainable energy transition
Through this campaign, we delivered critical insights to inform seabed condition, debris mapping, habitat status, and post-decommissioning environmental baselines. These outputs support key closure activities such as the removal of 500 m safety zones and preparation for over-trawl surveys.
The work highlights our ability to mobilise expert staff, in-house scientific equipment, and accredited laboratory services to deliver high-quality data under tight timelines – meeting the needs of a rapidly evolving offshore energy sector.
As decommissioning accelerates across the UK Continental Shelf, we continue to provide the integrated environmental support needed to deliver responsible, regulator-compliant outcomes from seabed to submission.
