Geological and Geotechnical Considerations Offshore Wind Infrastructure within the US Gulf of Mexico OCS

Abstract

Abstract Recently, the Bureau of Ocean Energy Management (BOEM) designated wind energy areas (WEAs) within the Gulf of Mexico, including six areas on East Texas and West Louisiana shelves. The objective of this study is to expand upon a previously completed BOEM-funded desktop study and focus on the geological and geotechnical conditions and the engineering constraints for the existing Gulf of Mexico WEAs. This study focused on compiling public domain geophysical and geotechnical data to evaluate the seafloor and near-seafloor geological and geotechnical conditions relevant to offshore wind within the Texas and Louisiana Gulf of Mexico shelf in areas designated by BOEM as suitable for offshore wind development. Data available from published scientific literature and offshore projects were integrated and evaluated using Geographical Information System (GIS) and seismic interpretation software to identify and map geohazards, seabed and subsurface conditions, and key stratigraphic geotechnical units. Given the data publicly available, investigation for this study is focused primarily on WEAs within the Bay City OCS block of East Texas and the Port Authur OCS block of West Louisiana. General sediment and subsurface structure vary between the East Texas and West Louisiana portions of the study area. The shallow strata associated with these areas reflect different fluvial and deltaic systems during the most recent glacioeustatic cycle. Both areas contain a thick unit of Pleistocene clay ≥ 65 m thick with interbedded sand units of variable thickness, but often > 20 m. In general, the Texas and Louisiana shelf has been subjected to heavy fluvial incision and deltaic progradation since the last glacial maximum. Based on these and other conditions, the suitability of various foundation concepts are assessed and discussed.