Experimental Modelling of the Caprock/Cement Interface Behaviour under CO2 Storage Conditions: Effect of Water and Supercritical CO2 from a Cathodoluminescence Study

• Published in: Geosciences
• Main Authors: Jobard, Emmanuel, Sterpenich, Jérôme, Pironon, Jacques, Corvisier, Jérôme, Randi, Aurélien
• Other Authors: GeoRessources, Institut national des sciences de l'Univers (INSU - CNRS)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL), Centre de Géosciences (GEOSCIENCES), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), ANR-05-PCO2-0007,GEOCARBONE-INJECTIVITE,Maîtrise de l'injectivité du CO2 dans les stockages géologiques(2005), ANR-08-PCO2-0006,INTERFACE,Comportement thermo-hydro-mécano-chimique de l'interface entre les ciments de puits d'injection et la formation de couverture en présence de (sc)CO2 et de gaz annexes(2008)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: CO 2 storage; Portland cement; clays; caprock; interface; well integrity; high-pressure experiment; [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology; Carbonic acid
• Online Access: https://hal.science/hal-01823502; https://hal.science/hal-01823502/document; https://hal.science/hal-01823502/file/geosciences-08-00185.pdf; https://doi.org/10.3390/geosciences8050185

International audience In the framework of CO 2 geological storage, one of the critical points leading to possible important CO 2 leakage is the behaviour of the different interfaces between the rocks and the injection wells. This paper discussed the results from an experimental modelling of the evolution of a caprock/cement interface under high pressure and temperature conditions. Batch experiments were performed with a caprock (Callovo-Oxfordian claystone of the Paris Basin) in contact with a cement (Portland class G) in the presence of supercritical CO 2 under dry or wet conditions. The mineralogical and mechanical evolution of the caprock, the Portland cement, and their interface submitted to the attack of carbonic acid either supercritical or dissolved in a saline water under geological conditions of pressure and temperature. This model should help to better understand the behaviour of interfaces in the proximal zone at the injection site and to prevent risks of leakage from this critical part of injection wells. After one month of ageing at 80 • C under 100 bar of CO 2 pressure, the caprock, the cement, and the interface between the caprock and cement are investigated with Scanning Electron Microscopy (SEM) and cathodoluminescence (CL). The main results reveal (i) the influence of the alteration conditions: with dry CO 2 , the carbonation of the cement is more extended than under wet conditions; (ii) successive phases of carbonate precipitation (calcite and aragonite) responsible for the loss of mechanical cohesion of the interfaces; (iii) the mineralogical and chemical evolution of the cement which undergoes successive phases of carbonation and leaching; (iv) the limited reactivity of the clayey caprock despite the acidic attack of CO 2 and (v) the influence of water on the transport mechanisms of dissolved species and thus on the location of mineral precipitations.