HR: 0800h
AN: NS31B-05    [Abstracts]
TI: Geophysical Monitoring of CO₂Injections in Decimetric Limestone Samples
AU: * Contraires, S
EM: contrair@ipgp.jussieu.fr
AF: Equipe de Géomateriaux et Environnement, Institut de Physique du Globe de Paris et Université Paris-Diderot, CNRS, 4, place Jussieu, Paris, 75005, France
AU: * Contraires, S
EM: contrair@ipgp.jussieu.fr
AF: Centre de Recherches IPGP-SCHLUMBERGER-TOTAL sur le Stockage Géologique du CO₂, 4, place Jussieu, Paris, 75005, France
AU: Vialle, S
EM: vialle@ipgp.jussieu.fr
AF: Equipe de Géomateriaux et Environnement, Institut de Physique du Globe de Paris et Université Paris-Diderot, CNRS, 4, place Jussieu, Paris, 75005, France
AU: Zamora, M
EM: zamora@ipgp.jussieu.fr
AF: Equipe de Géomateriaux et Environnement, Institut de Physique du Globe de Paris et Université Paris-Diderot, CNRS, 4, place Jussieu, Paris, 75005, France
AU: Zamora, M
EM: zamora@ipgp.jussieu.fr
AF: Centre de Recherches IPGP-SCHLUMBERGER-TOTAL sur le Stockage Géologique du CO₂, 4, place Jussieu, Paris, 75005, France
AU: Lopez, O
EM: lopez@ipgp.jussieu.fr
AF: Equipe de Géomateriaux et Environnement, Institut de Physique du Globe de Paris et Université Paris-Diderot, CNRS, 4, place Jussieu, Paris, 75005, France
AU: Lopez, O
EM: lopez@ipgp.jussieu.fr
AF: Centre de Recherches IPGP-SCHLUMBERGER-TOTAL sur le Stockage Géologique du CO₂, 4, place Jussieu, Paris, 75005, France
AU: Zuddas, P
EM: zuddas@ipgp.jussieu.fr
AF: Equipe de Géomateriaux et Environnement, Institut de Physique du Globe de Paris et Université Paris-Diderot, CNRS, 4, place Jussieu, Paris, 75005, France
AU: Zuddas, P
EM: zuddas@ipgp.jussieu.fr
AF: Centre de Recherches IPGP-SCHLUMBERGER-TOTAL sur le Stockage Géologique du CO₂, 4, place Jussieu, Paris, 75005, France
AB: Within the framework of the fight against greenhouse gases emissions, one of the adopted solutions is the carbon dioxide sequestration. Injections of this gas in underground reservoir will acidify the fluid saturating the pores of the rock, which can then react with the porous matrix. The fluid-rock interactions consisting on both dissolution and precipitation reactions may modify porosity and permeability of the reservoir. Monitoring, during the injection and storage phase, will be required to detect possible leaks through the geologic strata overlaying the reservoir or modifications of its hydraulic properties. Among the available monitoring methods, geophysical techniques appear particularly adapted. In order to quantify the effect of dissolution reaction on the geophysical observables, we performed laboratory experiments on decimetric limestone samples (10 cm diameter and 30 cm length). A CO₂saturated fluid percolated throughout the sample. During the experiments the core is placed into an original percolation device allowing to measure in situ and continuously different physical parameters (permeability, pH, electrical conductivity of both rock and fluid) during the solution flow through a sample. The output fluid was regularly sampled and the fluid chemical composition was analyzed. In addition, the P- and S-waves velocities and attenuations were measured along the sample (each centimeter) regularly. The results of the experiments, where a limestone reacts with CO₂saturated reactive fluid (pH=4), reaching a one order of magnitude permeability increase, show that the seismic waves velocity and attenuation measurements allow us to follow the evolution of the porosity along the sample. The 3% increase of the porosity and the creation of preferential flow paths (wormholes), detected by the seismic study, are in agreement with the X-ray Computed Tomography (CT), the variations of the electrical formation factor, and the chemical analyses of the output fluid.
DE: 1859 Rocks: physical properties
DE: 1895 Instruments and techniques: monitoring
SC: Near-Surface Geophysics [NS]
MN: 2007 Joint Assembly