New experimental sites for borehole geophysics, hydrodynamics and long-term monitoringITORING
Abstract
In order to provide platforms for the development of new downhole geophysical and hydrodynamic sensors, 4 sites are being developped with a series of nearby 100 m deep boreholes located with a few meters to 100 meters, at the most. The objective is to set-up a cluster of extremely well characterized in-situ laboratories at scales where experiments cannot be conducted in traditionnal labs. At least one borehole is continuously cored at each of the sites, and the core is fully characterized in petrological, petrophysical and geochemical terms. An emphasis is placed on fundamental and environmental applications such as hydrogeology, waste storage or the study of seismogenic faults, whether for characterization purposes or the development of long-term monitoring sensors and methods. These sites are developped with the support of CNRS, the University of Montpellier and the ALIANCE program financed by the European Commission. The 4 sites span different lithologies with granite at Ploemeur (Brittany, France), Miocene carbonates from a reefal platform in south Mallorca (Baleares, Spain), Valanginian marly limestone at Lavalette, near Montpellier (Languedoc, France), and unconsolidated sands in a coastal setting also near Montpellier. In the context of ALIANCE, the goal is to improve the investigation, characterisation and monitoring of coastal aquifers for vulnerability assessment. For this, a set of geophysical approaches for the quantitative evaluation of brine intrusion will be developped. This includes the design of 5 new geophysical and hydrodynamical logging/testing sensors. Two end-member sites in terms of hydrogeological behavior will be set up for long-term experimentation, the testing of the new tools, and the validation of site-specific experimental and modelling protocols from µm- to 100 m-scale. Active in-situ testing from short and longer-term injections with variable salinity fluids will simulate overdrafting or saline water intrusion.
- Publication:
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EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA....12966P