9:15 AM - 9:30 AM
[SCG61-14] Experimental investigation of reaction-induced stress and permeability evolution in MgO–H2O system
Keywords:Reaction-induced stress, Reaction-induced fracturing, permeability
To understand the controlling mechanisms of fluid flow during hydration reactions, we show one of the first experimental trial to measure the permeability evolution during hydration reactions. We use MgO–H2O system, where periclase (MgO) react with H2O to produce brucite (Mg(OH)2). The reaction involves solid volume increase of as much as +119%. Our earlier experiments have revealed that the reaction-induced stress in this system are controlled by the competition of reaction rate and stress-dependent deformation rate, and exceeds 40 MPa in this system which well exceeds the tensile strength of crustal rocks.
In this presentation, we have conducted flow thorough experiments to reveal the permeability evolution during hydration reactions. Experiments were conducted with sintered MgO with 4–14 vol.% porosity, under 100–300°C with 5–50 MPa confining pressure and 5–15 fluid pressures. Preliminary experiments showed rapid permeability decrease in 2–3 orders, and finally the stainless sleeve broke by the reaction-induced expansion. The rate of permeability decrease is a function of the confining pressure, suggesting that the deformation of the reactant (brucite) has significant control over the permeability evolution during hydration reactions. We will present further experiments with various reaction rate/deformation rate ratios, and discuss the controlling factors of permeability enhancement/reduction during hydration reactions.
Jamtveit, B., Austrheim., H., Mathe-Sørenssen, A., 2000. Nature 408, 75–78.
Jamtveit, B., Mathe-Sørenssen, A., Kstenko, Olga., 2008. Earth and Planetary Science Letters 267, 620–627.
Kelemen, P.B., Hirth, G., 2012. Earth and Planetary Science Letters 345–348, 81–89.
Plümper O., Røyne, A., Magrasó, A., Jamtveit, B., 2012. Geology 40, 1103–1106.