Coupled Models of Brittle-plastic Deformation and Fluid Flow: Approaches, Methods, and Application to Mesoproterozoic Mineralisation at Mount Isa, Australia

Abstract

Rock deformation has an important effect on the spatial distribution and temporal evolution of permeability in the Earth's crust. Hydromechanical coupling is of fundamental significance to natural fluid-rock interaction in porous and fractured hydrothermal systems, and in the assessment and production of hydrocarbon resources and geothermal energy. Shearing and fracturing of rocks can lead to the creation or destruction of permeability when fractures or faults form, or when existing structures are reactivated. Changes in stress orientation or fluid pressure can drive rock failure and create dilating fault zones that have the potential to focus fluid flow, or to breach seals above overpressured fluid compartments. Here, numerical models of deformation and fluid flow related to Mesoproterozoic copper mineralisation at Mount Isa, Australia, are presented that show how changes in deformation geometry in multiply deformed geological architectures relate to changes in dilation patterns, fluid pathways and flow geometry. Coupled numerical simulations of deformation and fluid flow can be useful tools to better understand structural control on fluid flow in hydrothermal mineral systems.

Numerical modelling of magma dynamics coupled to tectonic deformation of lithosphere and crust

“…Loret & Prevost 1991;Ehlers & Volk 1998;Rubin et al 2000;Lomov & Robin 2003;Khoei & Mohammadnejad 2011) and of porous rock containing hydrous fluids (e.g. Fournier 1996;Evans 2005;Gessner 2009;Yang 2002). These studies, however, are often based on different PDEs (e.g.…”

Three-Dimensional Mineral Prospectivity Modeling with the Integration of Ore-Forming Computational Simulation in the Xiadian Gold Deposit, Eastern China

“…In a numerical simulation study, such processes can be approximated and characterized by a series of partial differential equations, including Darcy's Law (describing fluid activities), Fourier's Law (describing thermal convection), the Mohr-Coulomb constitutive model (describing the mechanical behavior of materials), and the mass and energy conservation equation (describing the coupled effects of the thermal-hydraulic-mechanical and chemical processes). These governing equations have been specifically reviewed in many prior studies [36,38,41,44,[73][74][75][76], and further elaboration is beyond the scope of the study. The basic principle of numerical simulation is to discretize the geological body model of the study area into grids or elements.…”

“…In this study, the FLAC 3D 5.0 software (Fast Lagrangian Analysis of Continua in Three Dimensions [78], was employed. This powerful software allows for the simulation of fluid flow and heat transport in relation to tectonic deformation, and has been successfully applied to simulation in hydrothermal-structural coupling ore-forming systems [38,73,79]. FLAC 3D employs hexahedral elements for mesh discretization, which ensures good convergence and stability in the numerical calculations.…”

“…Previous researchers have generally concluded that fault zones and fractures are conduits for ore-forming fluid flow [81][82][83]. Refined architectures of the regional fault are essential, as the strain distribution and fluid migration occurs in fault zones [42,73]. Here we manually refined the Xiadian fault surface model constructed above to avoid the postore cutoff or deformation.…”

A Stress-Induced Permeability Evolution Model for Fissured Porous Media

“…Notable contributions include the network model (Bernabé et al 2010;Pan et al 2010;Zhu et al 1996;Zhu and Wong 1999), the discrete model (Cheng-Haw et al 2007) and the constitutive model (Bouteca et al 2000;Crawford and Yale 2002;Gessner 2009;Morris et al 2003;Pride and Berryman 1998;Rudnicki 2001;Yale 2002). Although these models are proposed taking into account either the microstructures of solid matrix, or the in situ stress, or the variation of porosity, most of these models are not complete, further development is required to precisely predict permeability evolution.…”