Engineering Geophysics for Geotechnical Characterisation of LNG Processing Plant Sites

Abstract

New Liquefied Natural Gas (LNG) processing plants are being developed and constructed along the eastern and western seaboards of Australia. In support of tendering processes for engineering design and construction, geotechnical site investigations are required over these large construction site foot print areas. The foot print areas often span across remote and inaccessible onshore and nearshore marine environments. Previously the domain of the resource exploration industry, geophysical technology is now being increasing used to support traditional site investigation techniques in order to provide complete and accurate geotechnical characterisation of large LNG construction sites. High resolution and near-surface geophysical techniques, when integrated with intrusive sampling and testing, are proving to be a cost effective and reliable way to image and test large volumes of onshore and nearshore footprint areas. Geophysical techniques are particularly helpful where borings and intrusive testing are limited for reasons that may include investigation budget limitations, inaccessibility and environmental disturbance constraints. Integration of geophysics with geotechnical investigative techniques offers the potential to improve management of project risks and costs, as well as enhance understanding of site conditions. This article describes some proven geophysical techniques in geotechnical investigations of large footprint LNG construction sites.