- Home
- Conferences
- Conference Proceedings
- Conferences
Near Surface Geoscience 2014 - 20th European Meeting of Environmental and Engineering Geophysics
- Conference date: September 14-18, 2014
- Location: Athens, Greece
- Published: 08 September 2014
181 - 185 of 185 results
-
-
Monitoring Techniques Using Autonomous Underwater Vehicles for Potential Seepage of CO2 from Sub-seafloor Storage Sites
Authors M. Cevatoglu, J.M. Bull, D.P. Connelly, A. Lichtschlag, I.C. Wright, R. James, T. Le Bas, S. McPhail and K. ShitashimaSummaryAlthough a number of Carbon Capture and Storage sub-seafloor storage sites are now either in operation or planned for CO2, little is known about the effect of potential seepage on marine ecosystems. Here we describe a comprehensive field campaign to the North Sea (RRS James Cook Cruise 77) that used Autosub 6000 to test methods for detection of seepage, including formation fluids, natural gas and CO2, as it passes through the sedimentary overburden and into the water column, and develop monitoring strategies suitable for all offshore carbon capture and storage projects. In this paper we describe the Hugin Fracture, a 2 km long discontinuity imaged on the seabed, and associated fluid flow activity, revealed by geophysical observations including high reflectivity acoustic anomalies within the overburden. Further results in favour of active fluid flow along this fault will be presented, using a combination of multidisciplinary datasets comprising video photography, Eh sensor and sediment samples.
-
-
-
Integrated 3D Ground Models for Cost-effective Foundation Design, Construction and Risk Reduction of Offshore Windfarms
Authors S.D. Pearce, A.B. Hart, L.D. Jacques, G. Maderni and J. ArthurSummaryAn integrated ‘Geoteam’ has used state-of-the-art geophysics and ground modelling software and interpretative techniques to reduce the amount of ground investigation required and improve the understanding of the site. This was achieved by integrating an interpretation of available geophysical data with the geotechnical data acquired during the site investigations and the findings of a detailed geological desk study, to build a 3-dimensional ground model for the site and create bespoke maps characterising the subsurface ground conditions of the site. This innovative integration of data into a single multi-purpose 3D ground model has helped the wind farm developer reduce geotechnical investigation costs and provide reliable information for the turbine design and installation.
The project outputs have also proven to be an effective method for the identification, understanding and communication of geological and geotechnical risk to the developer and designer, thus allowing them to make informed choices
-
-
-
Integrated Geomodel – Horns Rev 3 Case Study
Authors A.B. Medhus, S.B. Marstal, M. Laier, A. Rosborg, B.R. Petersen, J. Henssel and L. KlinkbySummaryEnerginet.dk is developing the Horns Rev 3 Offshore Wind Farm.
In order to allow developers to evaluate the limitations and opportunities for foundation of turbines geophysical and geotechnical data were collected providing a basis for assessment of soil conditions.
Geophysical data were collected in 2012 and the first interpretation was carried out without any boreholes or CPTs available. The conceptual geological model was consequently constructed from available literature. The resulting model presented Holocene units generally less than 10–15 m thick, but locally as deep as 20–25 m.
In 2013 geological and geotechnical information was collected. The borehole and CPT data showed poor correlation to the existing geological model. The acquired data indicated Holocene sediments to much greater depths. Age determination (C14) performed on a single sample emphasized this geotechnical observation.
Integrated interpretation of geophysical data, borehole and CPT data revealed a complicated Holocene setting down to 40 m in large part of the area with significant regional variation in clay thicknesses.
This integrated model is presented in this study.
-
-
-
UXO Characterization by 3D Seismic Constrained Magnetometry Inversion
Authors R. Morrow, M.E. Vardy, R. Hamilton, J.K. Dix, T.J. Henstock and L.J.W. PinsonSummaryMarine Unexploded Ordnance (UXO) identification and clearance is a massive growth industry, driven by the expansion into deeper water resources and offshore renewables. The standard survey too of choice is a magnetic gradiometry system, which benefits from being cheap, easy to use, and able to rapidly cover spatially extensive areas. In theory, using the 3D Analytical Signal, such systems are also capable of characterizing the magnetic susceptibility of the UXO targets. Given the huge areas to cover and often large number of identified targets, this kind of material properties information is invaluable for distinguishing between UXO that need removing and those that can remain in situ. However, inversion of the Analytical Signal is a multi-paramter, non-unique process, difficult to perform reliably based on magnetometry data alone. Here we demonstrate the combined use of decimetre-resolution 3D seismic and gradiometer data for UXO characterization. The 3D seismic data are used to constrain the location, size, and burial depth of UXO targets prior to inversion of the Analytical Signal. Together, these techniques are used in combination to characterize 89 UXO targets that are verified using post-survey dredging.
-
-
-
Geophysical Imaging of the Bottom Sediments of Underwater Quarries
Authors R.G. Francese, M. Giorgi, A. Bondesan and S. BusoniSummaryThe definition of the nature of the bottom sediments in underwater gravel and sand quarries represents a major problem for the Mining Authorities in Italy. Bylaw the residual fine sediments could not be dumped in the water. Furthermore the damping of fine sediments is often used to mask non-compliance excavations. The standard monitoring procedure based on Single-Beam Echo Soundings delivers low resolution and insufficient sub-bottom penetration.
-