Illuminating the world hidden beneath

The Xodus geohazard team, formerly Ocean Geo Solutions, is now supporting the offshore wind industry in the US, with Lisa Hill based up in the Boston office to support the growth of this new type of work.

Geophysical and geohazard assessments are required for offshore wind, because, like for oil and gas developments, offshore wind developers are blind to what the sea floor of their development site looks like. The geology of a region can change over just a few kilometres… and drastically influence the schedule and cost of a proposed site’s development. The planning of an offshore wind farm, or other offshore installation, requires knowledge of the morphology, geology, sea floor and sub-seafloor conditions. Not only is the planning of the wind farm affected by the seafloor, but also the need to understand the sub-seabed soil conditions so that geo-engineering can effectively engineer turbine foundations and buried cables. Geophysical surveys help offshore developers de-risk a site, but also preserve what treasures lay hidden within these sites. For example, geophysical surveys can identify shipwrecks, archaeological sites from when sea levels were lower than today, coral reefs, and other benthic communities that are protected under US regulations. All the knowledge that the seafloor holds must be understood before any offshore developments can be conducted, and a geophysical survey is the tool to open that window.

Geophysical surveys for renewable energy geohazard assessments generally use many of the same sensors as a standard geohazard site survey but will usually focus more on the seafloor to around 50 meters below seafloor, whereas for oil and gas we can assess up to 2000 m below the surface. This is because developing a wind farm site generally does not penetrate the sub-sea soils by more than around 30 meters. Focusing on the shallow sections allow us to use a higher frequency sensor, which produces increased resolution enabling a clear understanding of the constraints and opportunities of the site being investigated. These sensor packages can produce datasets which range from extremely large wind farm survey site surveys over multiple lease areas, covering hundreds if not thousands of square kilometers, down to smaller state water landfalls to determine possible locations of cable routes to shore. Each of these sensor packages provide different, yet equally important datasets which cover various aspects of the geohazard assessment.

Our geohazard teams located in Boston and in Houston use highly specialized skills to assist with the acquisition of the data, whether on-board the vessel, or in an onshore role helping as a technical expert consultant, or remote-based quality assurance and data processing. Having us involved in the survey acquisition will ensure that all requirements are met from local to federal levels.

After we have successfully completed the data gathering for a site, our team will compile and load all datasets into our specialized processing and interpretation software. With this, we can then determine all the potential problems or hazards a site may contain, and produce reports and charts which efficiently describe those constraints, and even provide recommendations for possible mitigation techniques for turbine jackets, inter-arrays, proposed landfalls, even essential information for export cable micro-routing

The presence of geohazard expertise is new in the Xodus Boston office, but as the offshore wind market continues to grow at a tremendous pace, we are confident our team will grow with it. With support from the established geohazard team in Houston, our combined skill set provides excellence in geophysical interpretations, providing both oil and gas operators and renewable energy developers with the confidence to develop and operate their sites safely.

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