SIMEx at Maguelone (Languedoc Coastline, France): a Shallow Hydrogeophysical Monitoring Site for CO2 Storage

An experimental setup for shallow subsurface hydrogeophysical monitoring has been installed at the Maguelone site, located along the Mediterranean lido of the Gulf of Lions near Montpellier, France. This experimental site was developed in the context of MUSTANG EC project (FP7). SIMEx (Shallow Injection Monitoring Experiment) is a unique opportunity to test in a cost effective manner a full suite of coordinated monitoring techniques, either from surface or downhole. The field spread includes an injection hole, a logging hole, a downhole hydrodynamic observatory based on a pore fluid sampling completion from WestBay (SWS), a downhole seismic observatory, plus surface seismic observatories. This coordinated set of observatories should lead to the design of integrated sensors and methods for the monitoring of gas injection in deeper reservoirs. More recently, nitrogen injection was undertaken to measure the site response to gas injection. Nitrogen was chosen because of the reducing nature of the in-situ environment present in the shallow subsurface at Maguelone, precluding oxygen injection to avoid massive bacterial developments. The next phase of SIMEx will be that of CO2 injection using similar surface and downhole hydrogeophysical monitoring.