Accelerating Offshore Wind: The Power of Integrated 3D Surveys

Offshore wind development is accelerating globally, driven by ambitious energy transition goals. Yet, one persistent bottleneck remains: site characterization. Traditional, sequential approaches often struggle to keep pace with the scale and complexity of modern wind farms.

This article explores how integrated Ultra-High Resolution 3D (UHR3D) geophysical and hydrographic surveys offer a transformative solution, enabling faster, more precise, and cost-effective site characterization.

The Challenge of Conventional Workflows

Before construction can begin, developers need a deep understanding of seabed and subsurface conditions. Conventional workflows are typically iterative, involving multiple surveys over several years—starting with 2D reconnaissance and slowly building detail.

This cyclical approach introduces delays, increases costs, and often leaves residual uncertainty in subsurface models, as the subsurface is ultimately not investigated in full 3D1.

Why 3D UHR Matters

The shift from 2D to UHR3D seismic data enables full volumetric imaging of the shallow subsurface soil units (up to 100m for offshore wind). This advanced imaging offers several key advantages:

• Improved Hazard Detection: Better identification of geohazards such as boulders.
• Quantitative Soil Prediction: Prediction of soil properties, including stiffness and strength.
• Optimized Geotechnical Testing: Full coverage 3D data can reduce the need for dedicated deep geotechnical testing at every foundation location2.

Integrated Survey Design in Action

Recent projects in Northern Europe by TGS have proven the benefits of a fully integrated approach. These surveys combined multiple technologies in a single-pass operation:

• UHR3D Seismic: For 3D subsurface imaging.
• Multibeam Echo Sounder (MBES): For bathymetry.
• Side Scan Sonar (SSS) & Magnetometer (MAG): For seabed object mapping and ferrous object detection.

By acquiring all data simultaneously, vessel time is reduced, and disruption to other marine activities is minimized. High-bandwidth satellite connectivity allowed for near-real-time data transfer and parallel processing, enabling rapid delivery of insights3.

Case Study Insights

In one 100 sq km survey, UHR3D data went beyond standard seismic use. Qualitative and quantitative analyses enabled the mapping of subtle changes in soil stiffness within chaotic glaciomarine sediments—variations that closely matched geotechnical test data.

Furthermore, the 3D data significantly improved risk assessment for boulders. Numerous subsurface features (~1m in size) were identified as potential boulders, while many anomalies initially flagged by 2D data were reclassified as iceberg scour marks when viewed in 3D, avoiding unnecessary conservatism 4.

Time and Cost Benefits

Front-loading a comprehensive 3D survey offers compelling advantages:

• Avoid Multiple Campaigns: Reduces the need for iterative geophysical surveys.
• Accelerate Planning: Speeds up geotechnical planning and overall project timelines.
• Reduce Over-Engineering: Better subsurface understanding allows for more tailored foundation designs.

While upfront costs may be higher, comparative analysis shows that cumulative site characterization costs can be significantly lower5.

Conclusion

Integrated UHR3D surveys represent a paradigm shift in offshore wind site characterization. By providing a holistic view of the seabed and subsurface, they enable smarter, faster, and more cost-effective decisions—essential for meeting the industry's evolving demands.