Stress from NaCl crystallisation by carbon dioxide injection in aquifers

International audienceThe goal of this paper is to identify the mechanical impact of water evaporation and salt crystallisation during supercritical carbon dioxide injection (drying-out process) in aquifer rocks. The precipitation of salt and the resulting crystallisation pressure are inferred from the chemical equilibrium of the carbon dioxide-rich gas phase, the in-pore brine and the crystal. The induced rock strain and equivalent tensile stress are then estimated within the framework of isotropic linear poroelasticity. A one-dimensional numerical simulation is conducted to illustrate the ability of the model to estimate the poromechanical behaviour of a structure submitted to a constant flow of nearly dry supercritical carbon dioxide

Dependence on injection temperature and on aquifer’s petrophysical properties of the local stress applying on the pore wall of a crystallized pore in the context of CO

The development of CCS (carbon capture and storage) currently faces numerous problems and particularly the precipitation of salts induced by the drying of the porous medium during injection of carbon dioxide in deep saline aquifers. This precipitation has several consequences, and particularly the creation of a crystallization pressure which can have an important mechanical impact on the host rock. Literature on crystallization pressure is one century rich of experimental and theoretical works. However, applications have been performed in the field of civil engineering and building science only, and, despite they are of paramount importance in the context of CCS, studies about this phenomenon in deep reservoir conditions are currently lacking. In this paper, we retrieve the classic crystallization pressure equation within the framework of geochemistry and present its explicit form of dependence with temperature, pressure, and composition. Evaluation of the crystallization pressure has then been proceeded considering the injection conditions and a sketch of in-pore crystallization process. The evolution of the local stress transmitted to a crystallized pore wall is found to be strongly related to the petrophysical properties of the medium and to the injection temperature of the carbon dioxide under the assumption of constant salt concentration during the precipitation process. Values differ strongly with the considered mineral, depending particularly on the solubility, and can reach in some conditions 165 MPa, making crystallization pressure a major factor in the mechanical behavior of the aquifer

Stress from nacl crystallization by CO2 injection in aquifers

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Experimental investigation of the influence of supercritical state on the relative permeability of Vosges sandstone

International audienceMeasurements of relative permeabilities involve complex and long experiments, especially when dealing with supercritical carbon dioxide at high pressures and temperatures. However, the development of CCS (Carbon Capture and Storage) underlined the need of such experiments in order to carry-out the indispensable simulations of the behavior of deep saline aquifers or other geological formations subjected to carbon dioxide injection. In this article, we present the measurement of relative permeabilities of a sandstone with a new experimental set-up with the fluid pairs gaseous CO2/water and supercritical CO2/water. For highly permeable and non-reactive materials, the results are almost identical, showing little influence of the pressure, temperature, and physical state of the considered fluids on the obtained data

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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