Modeling Multicomponent Fluid Flow in Deforming and Reacting Porous Rock

Abstract

We propose a coupled hydro-mechanical-chemical model and its 1D numerical implementation. We demonstrate its application to the model filtration of a multicomponent fluid in deforming and reacting host rocks, considering changes in the densities, phase proportions, and the chemical compositions of the coexisting phases. The presented 1D numerical implementation is illustrated by the example of soapstone formation from serpentinite during the filtration of Н₂О−CО₂ fluid with a low CО₂ concentration coupled with the viscous deformation of the mineral matrix, considering the MgO−SiO₂−Н₂О−CО₂ system. The numerical results show the propagation of a porosity wave by means of a viscous (de)compaction mechanism accompanied by the formation of an elongated zone with higher filtration properties. After the formation of such a channel, the formation and propagation of the reaction fronts occur and are associated with the transformation of the mineral composition of the original rock. During H₂O−CO₂ fluid filtration, starting with 1 wt % dissolved CO₂, carbonization of hydrated serpentinite starts, specifically antigorite transforms to magnesite and talc.