Integrated site characterisation supports floating offshore wind development in the North Sea

We delivered a fully integrated marine site characterisation programme across Bellrock and Broadshore to support early-stage development. 

Geophysical data acquisition was completed using a single-pass, multi-sensor survey approach, collecting MBES, side scan sonar, magnetometer, and sub-bottom profiler data simultaneously while minimising acoustic and electrical interference. Over 3,100 km of survey data was acquired across both sites, providing high-resolution seabed mapping and identification of geological features and hazards. 

Environmental surveys, delivered in parallel, included grab sampling, drop-down camera inspections, and eDNA sampling to support environmental impact assessment requirements. 

Geotechnical investigations were undertaken using UTEC’s Portable Remotely Operated Drill (PROD) seabed drilling system, completing 35 locations including sample and CPT boreholes at offshore wind turbine and substation locations. Despite challenging sand conditions, including very dense sands, the tailored sampling approach achieved average recovery rates of approximately 80%, ensuring high-quality data for ground modelling. 

Operations were supported by coordinated offshore and onshore teams, with rapid data transfer and processing enabling continuous quality control and efficient project delivery. 

UTEC coordinated with a trusted onshore partner laboratory, and prepared laboratory testing results collaboratively with our client. The onshore laboratory testing was completed with UTEC oversight, and factual reports delivered on completion.

Innovations in action

• Single-pass geophysical survey combining MBES, SSS, magnetometer, and sub-bottom profiling 
• High-resolution seabed mapping with MBES at 0.5 x 0.5 m resolution 
• PROD seabed drilling system for seabed and downhole mode locations
• Optimised sampling techniques achieving high recovery rates in sandy soils 
• Integrated offshore and onshore data workflows with rapid turnaround 
• Environmental survey techniques including grab sampling, drop-down camera, and eDNA

The result

We delivered high-quality, integrated datasets across geophysical, environmental, and geotechnical scopes, enabling the development of a detailed ground model for both sites. The results supported environmental assessment, informed turbine layout and foundation design, and reduced early-stage project risk. High recovery rates and efficient survey execution ensured reliable data for decision-making, while the use of local suppliers supported regional development objectives.