Permeability Reduction due to Precipitation of Quartz under Nonisothermal Conditions

Abstract

Many problems concerning the origin and exploitation of geothermal reservoirs demonstrate the need for models of reactivesolute transport. Of particular interest to us is the coupling between dissolution/precipit at i o n reactions and transient-flow behavior. In an effort to account for observed flow-rate reductions during experiments on samples of granite held in a temperature gradient (summarized at this meeting in 1981 by Moore and others ), we examine the effect of quartz prec i p i t at i o n on fluid flow. Our results confirm earlier inferences that reactions responsible for porosity reduction were affected by kinetic factors. Although our results show substantial flow-rate reductions, we are unable to reproduce measured silica concentrat ions of the outlet fluid by considering the behavior of silica phases without regard forth at of the feldspars and micas.