| Title | Modelling the Evolution of Granite Permeability at High Temperature |
|---|---|
| Authors | Sutopo, Stephen P. White and Norio Arihara |
| Year | 2000 |
| Conference | World Geothermal Congress |
| Keywords | CHEM-TOUGH2, chemical modelling, deposition, granite, permeability evolution |
| Abstract | In this paper we describe modelling the complicated processes of mineral deposition/dissolution in porous or fractured rock at high temperatures. The effect of this process on the evolution of permeability and porosity within the rock is calculated. A numerical model was constructed using CHEMTOUGH2 to simulate a recent experimental study of permeability changes in Westerly granite. As cementation proceeds, surface area available for deposition is modified, inducing changes in the kinetic deposition rate. In order to model this feedback effect adequately, we included a correlation between surface area and porosity. These results are compared to the measured permeability and flowrate changes over time in the granite core flood experiments of Moore et al. The temperature range of the experiments was 300 ñ 500o C. Model predictions match the experimental permeability and flowrate curves quite well at late time with less than 10% error in all cases. In some cases the match to early time data is not so good with errors up to 30% in some cases. |