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

MPPS 2011, Symposium on Mechanics and Physics of Porous Solids : A tribute to Pr. Olivier Coussy, Marne-la-Vallée, 18-20 avril 2011

This book is dedicated to Olivier Coussy, the prominent scientist and engineer who developed the fundamentals of poromechanics theory that were transformational in many application of civil environmental and petroleum engineering, bioengineering and sustainable development of materials and structures. Olivier passed away on January 15, 2010. He was the colleague and friend of all the contributors to this book. To honor the memory of Olivier Coussy , Ecole des Ponts ParisTech and IFSTTAR (French institute of science and technology for transport, development and networks) have organized a symposium held at Ecole des Ponts ParisTech from April 18 to 20, 2011. The theme of this symposium was chosen after his last monograph (Mechanics and Physics of Porous Solids, J Wiley & Sons, 2010) which embodies his most recent vision of the Poromechanics at the interface between physical chemistry and solid mechanics. Because the interface between those two fields is not often explored as he said, he aimed to bridge the gap between physical chemistry, which governs what happens at the level of the pore, and solid mechanics, which is the natural frame in which deformations, stresses and fluid transport are addressed and quantified at the macroscopic level of the porous material. In this vein the organizing committee of the symposium intended to gather academics and industrials that either develop or utilize the concepts of the mechanics and physics of porous solids as envisioned by the late Pr.Coussy

Low incidence of SARS-CoV-2, risk factors of mortality and the course of illness in the French national cohort of dialysis patients

International audienceThe aim of this study was to estimate the incidence of COVID-19 disease in the French national population of dialysis patients, their course of illness and to identify the risk factors associated with mortality. Our study included all patients on dialysis recorded in the French REIN Registry in April 2020. Clinical characteristics at last follow-up and the evolution of COVID-19 illness severity over time were recorded for diagnosed cases (either suspicious clinical symptoms, characteristic signs on the chest scan or a positive reverse transcription polymerase chain reaction) for SARS-CoV-2. A total of 1,621 infected patients were reported on the REIN registry from March 16th, 2020 to May 4th, 2020. Of these, 344 died. The prevalence of COVID-19 patients varied from less than 1% to 10% between regions. The probability of being a case was higher in males, patients with diabetes, those in need of assistance for transfer or treated at a self-care unit. Dialysis at home was associated with a lower probability of being infected as was being a smoker, a former smoker, having an active malignancy, or peripheral vascular disease. Mortality in diagnosed cases (21%) was associated with the same causes as in the general population. Higher age, hypoalbuminemia and the presence of an ischemic heart disease were statistically independently associated with a higher risk of death. Being treated at a selfcare unit was associated with a lower risk. Thus, our study showed a relatively low frequency of COVID-19 among dialysis patients contrary to what might have been assumed

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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