May 2022 TAG Webinar
A Framework for linking Geophysical and Geotechnical Observations
May 11, 2022 

Presentation Title:  A Framework for linking Geophysical and Geotechnical Observations 
Presenter:  Mark Vardy, MSci. MRes PhD – SAND Geophysics

Mark Vardy, Ph.D., SAND Geophysics
Date:  May 11, 2022
Time: 4:00 PM Mountain Time US (3:00 PM Pacific; 5:00 PM Central; 6:00 PM Eastern )

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https://us02web.zoom.us/meeting/register/tZEpdO-rqjMoH9zPCp7S-V9TmkIZ7UyVkY08 

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Presentation Description:

Geotechnical and geophysical observations are the two pillars upon which marine site survey investigations are built. Geotechnical methods provide highly detailed (centimetric resolution) information regarding the stratigraphic variation in the geotechnical parameters at a number of individual sample locations distributed across the site. From these geotechnical observations, a detailed characterization of the soil conditions in terms of key engineering parameters can be derived from the observations themselves and/or associated laboratory testing. Geophysical methods provide detailed information regarding the spatial and stratigraphic variation in the geological structure and bulk physical parameters continuously along 2D profiles and/or 3D volumes, depending on the nature of the acquired data. However, when applied to marine site surveys, the most ubiquitous geophysical observations (i.e., seismic reflection data) are often seen as little more than a qualitative tool, with the ability to infer bulk physical properties oft ignored or underrated. The uncertainties in these predicted ground conditions, therefore, increase dramatically away from the sampling locations, often leading to layout-driven sampling strategies and/or engineering over-design, which is not necessarily the most efficient approach.

In his talk, Dr. Vardy I will outline a proposed framework that can be used to link geotechnical and geophysical observations in a semi-quantitative manner. This framework should not be considered a definitive method or workflow for translating geophysical observations into equivalent geotechnical observations. Rather, this framework should be considered a geoscience Babel fish, bridging the communication gap between geophysicists and geotechnical engineers, allowing users/interpreters to understand how observed spatial and/or stratigraphic changes in one set of parameters are likely to be reflected in other parameters. To illustrate the application of this framework, a range of different case study examples will be used, covering all phases of site investigation surveys from appraisal to pre-FEED and post-installation. Particular focus will be paid to energy transition, with examples showing how seismic reflection data can be better leveraged in various ways for large-scale offshore wind projects, targeting both cable and foundation depths. 

Biography:
Mark Vardy obtained an MPhys in Physics and Astronomy from the University of Sheffield in 2004, before moving to the University of Southampton where he studied for an MRes and then a PhD in Marine Geophysics in 2009. After his PhD, he stayed on as a Research Fellow, before becoming a Principle Scientist for NERC. In 2013, he co-founded SAND Geophysics.

Mark has worked on all manner of offshore projects, from inshore infrastructure developments to large-scale offshore renewables installations, and with clients including RVO, Ørsted, RWE, Shell, BP, TOTAL, De Beers, CH2M, AECOM, and National Grid. He specializes in the development of novel high-resolution geophysical solutions to marine near surface problems. He was a co-inventor of the 3D Chirp decimetre-resolution 3D seismic system, has designed a multi-channel seismic streamer in collaboration with Geometrics, and developed two specialist seismic software packages specifically designed to provide optimal qualitative and quantitative imagery from high-resolution seismic reflection data. In particular, his development of machine learning workflows to predict geotechnical properties from seismic reflection data has garnered significant interest within the marine site survey sector.

Mark sits on the Shallow Marine Geophysics committee for EAGE, is a Deputy Editor for Near Surface Geophysics, and has given invited, keynote speeches at both national and international conferences.