EAGE Near Surface Geoscience 2023
Join us for our upcoming talks in collaboration with Tellus Environment and EDF. We'll discuss the benefits of geostatistics in detecting UXO and using correlated data to improve soil property mapping. See you in Edinburgh, and have your questions ready for our team!
Spatial statistical analysis and geostatistical mapping of offshore magnetometric acquisition data
September 5, 2023 – 9:00 am to 10:40 am
Session: Challenges and Opportunities in Offshore Wind – 1st Conference on Sub-surface Characterisation for Offshore Wind
Before constructing wind turbines, overseas measurements of the total magnetic field were conducted to locate the Unexploded Ordnances (UXO) buried since the Second World War. A set of two magnetometers pulled by a boat was used to measure the magnetic field in go-and-return trajectories. The measurements along north and southward trajectories were correlated. However, the magnetometers systematically recorded a relatively higher magnetic field during the northward course. Using both north and southward measurements resulted in a heterogeneous dataset, which created azimuthal artifacts on the produced maps. A Gaussian transformation was used to adapt the statistical distribution of the southward measurements to the northward ones and make the dataset homogeneous. Therefore, the azimuthal artifacts were considerably reduced, and potential UXO locations were detected more easily. Exploratory data analysis and mapping steps were done entirely in the Isatis.neo™ geostatistical software.
Improving seismic velocity mapping using Standard Penetration Test data in a cokriging interpolation
September 6, 2023 – 3:50 pm to 5:10 pm
Session: Geophysics in 3D Geological/Geotechnical Modelling – 29th European Meeting of Environmental and Engineering Geophysics
In geotechnical studies, a preliminary step is to characterize soil parameters. This project aims to map the velocity of shear sonic waves (Vs) in the soil, while in-depth Vs measurements are limited to a few drillholes. Interpolation based on insufficient measurements results in smoothing the spatial variability of the studied parameter. On the other hand, Standard Penetration Tests (SPT) are abundant in the site under investigation. Being correlated with Vs., the SPT data are used to improve the interpolation of Vs. In the framework of the geostatistics theory, the Vs. interpolation is improved using the multivariate method of collocated cokriging. It means the areas lacking Vs measurements are interpolated by the aids of the correlated auxiliary information (SPT); therefore, the spatial variability of Vs is better reproduced. Exploratory data analysis and mapping steps are done entirely in the Isatis.neo™ geostatistical software.
Authors: Pedram Masoudi, Hélène Binet, Frédéric Rambert, Yvan Assy (Geovariances) and Cyril Simon and Baptiste Pelletier (EDF).