Numerical investigation of the effect of heterogeneous permeability distributions on free convection in the hydrothermal system at Mount Isa, Australia

摘要

Fluid flow patterns due to free thermal convection in permeable rock masses have been investigated for the 3D geological architecture around the Mount Isa lead-zinc-silver and copper deposits. Key results for the range of parameters explored here are: (1) Flow pattern and temperature distribution in stratigraphic units with homogeneous permeability are similar to those in units with the same average permeability in a heterogeneous distribution. (2) The geometry of one highly permeable stratigraphic unit governs fluid flow to an extent where it spatially attracts a convection cell, irrespective of the volume of adjacent permeable units. (3) Even in a complex and heterogeneous system with patches of low permeability along the fluid pathways, the Rayleigh number can be used to determine whether free convection will occur or not.