Journal of Earth Science & Climatic Change
Open Access

Abstract

Geological storage of CO2 could be a viable way of limiting the effect of anthropogenic carbon dioxide emissions on the global warming. However, the containment of the gas has to be ensured and the understanding of how CO2 could leak out of the sequestration formation is of great importance. The loss of the integrity of one or several wells located on the storage site represents the greatest risk of CO2 leakage. For example, cement carbonation is one of the mechanism which can impair sealing capacity of a well. The knowledge of the long-term evolution of a hardened portland cement exposed to CO2 -rich fluids is therefore a key issue to ensure confidence CO2 geological storage. Reactive transport modelling appears as the most reliable way to forecast the cement annular at very long term. However, reactive transport codes require reliable input thermodynamic data. A thermodynamic dataset based only on calorimetric data does not guaranty accurate results. Furthermore, a combination of reversal brackets and calorimetry is a way of getting an internally consistent thermodynamic dataset. The existing internally consistent thermodynamic databases include important phases concerning cements as portlandite, calcium carbonates or some calcium silicate hydrates (CSH) that may occur in a hydrated cement paste. The purpose of this study is to obtain new experimental results relative to the stability conditions of gyrolite (Ca4 Si6 O17H2 ) under well constrained pressure-temperature conditions. These bracketing experiments provide constrains to optimize and estimate thermodynamic data of the studied minerals.

Biography

Thomas Millan is a physico-chemistry PhD student at IFP Energies nouvelles in Rueil Malmaison (France) and in collaboration with the EMSE (Ecole Nationale Supérieure des Mines de Saint Etienne) and the Paris 6 University. His researches focuse on cement behaviour during CO2 storage under geological conditions and the modelling of long term evolution of the cement mineralogy in CO2 environment