Reactive Flow-Induced Alteration and Permeability Evolution in Volcanic Rock Analogues
Andrea Mazzeo 1, Marie Violay2, Alexandra R.L. Kushnir1.
Affiliations: 1 Rock Physic and Geofluids Laboratory, EPFL, Lausanne, Switzerland; 2 Laboratory of Experimental Rock Mechanics EPFL, Lausanne, Switzerland
Presentation type: Poster
Presentation time: Thursday 16:30 - 18:30, Room Poster Hall
Poster Board Number: 26
Programme No: 3.8.10
Abstract
The dynamics of volcanic systems are partly governed by rock-fluid interactions, with chemical reactions altering fluid flow pathways, modifying the physical properties of these rocks. Changes in permeability and porosity may eventually result in the sealing of fluid pathways, increasing the propensity to explosive behaviour. We assess how alteration affects sample microstructure and permeability. To do this, we use the novel High temperAture Reactive flOw permeabiLity Device (HAROLD) to perform in-situ flow-through experiments at temperatures up to 500 °C and an effective confining pressure of 30 MPa. We alter structurally simple volcanic rock analogues - sintered soda-lime glass bead samples with porosities ranging from 0.05 to 0.25 - with reactive fluids enriched in silica or calcite. Steady-state permeability is monitored over time as reactive fluids circulate and alter the microstructural properties of the samples. Pore fluid is sampled before and after interaction with the sample, and fluid chemistry is used to determine the timescales of reactions. We use micro-computed tomography (μCT) to image pre- and post-experiment microstructure, allowing for precise quantifying of the geometry of alteration. Our findings will be used to provide critical insights into the role of permeability changes in fluid flow in volcanic systems.