Industry Insights | 3D Ground Models for Offshore Windfarm Development
Is it possible to combine the merits of high-res and UHR 3D data from towed-streamer seismic when building regional ground models?
In this edition of his Industry Insights series, Chief Geoscientist Andrew Long looks at the role of geosciences in the windfarm lifecycle.
He starts with a recent publication on the topic in Earth Science, Systems and Society, where the authors advocate the integration of geological and geotechnical approaches to develop three-dimensional (3D) ground models that will permit the bespoke design of turbine foundations.
Future offshore wind developments focus on very large turbines with very wide foundations. Installation costs are high. A site-specific approach is feasible because of the vertical resolution of the geophysical data. However, the traditional approach, where 2D data is interpolated into a 3D model, suffers from spatial uncertainty in soil properties and stability that rapidly increases with increasing depth below the seafloor, he explains.
Techniques commonly applied in the oil and gas industry could reduce installation costs and decrease the risk of failure, such as the wider use of 3D geophysical data collection, and Ultra-High Resolution (UHR) 3D surveys and P-Cable, to provide high-resolution and improved spatial control. Adoption of P-cable techniques could be particularly attractive to improve site lifecycle management because geophysical data can be (re)collected during windfarm operations, and thereby support decommissioning and repowering plans.
In this article, Andrew compares the features of HR, UHR seismic, and UHR acoustic profiling, and then summarizes the traditional approach when building windfarm ground models.
He looks at the difference in the accuracy of data acquired using towed-streamer seismic methods and the difference this can make to subsurface insights and feature detection in the near surface. The article considers different strategies to combine the merits of both HR and UHR 3D towed-streamer seismic when building regional ground models in an efficient manner and integrate contemporary views on the role of geosciences throughout the windfarm lifecycle.