Estimation of in situ permeability of deformation bands in porous sandstone, Valley of Fire, Nevada

At the Valley of Fire State Park, southeastern Nevada, there is a unique re lationship between deformation bands and the distribution of diagenetic min eralization in the Aztec Sandstone, a reservoir and aquifer analog exposed at the surface. Distinct diagenetic alteration fronts are refracted where t hey cross deformation bands. Modeling this refraction as resulting from the advective transport of a nonreactive solute, we are able to back out that deformation band permeability is reduced by an average of 1.3 orders of mag nitude relative to the surrounding rock with a range of 0.7 to 2.1 orders o f magnitude. The geometric relationship utilized in our approach formed in the subsurface during diagenesis and provides an in situ measurement of per meability not affected by uplift and erosion or by damage associated with c ollecting a sample from a well bore. Our estimation is about 1 order of mag nitude lower than values reported in the literature for similar rock types.