| Title | Three-Dimensional Modeling of Injection Induced Thermal Stresses with an Example from Coso |
|---|---|
| Authors | A. Ghassemi, S. Tarasovs |
| Year | 2004 |
| Conference | Stanford Geothermal Workshop |
| Keywords | thermoelastic mechanism, reservoir simulation, enhanced geothermal system |
| Abstract | Poro-mechanical, thermal, and chemical pro-cesses can play a significant role when devel-oping enhanced geothermal systems. These processes occuronvarious timescales andthe significance of their interaction varies with the problem of interest. Of particular importance is the thermo-mechanical coupling during in-jection operations (time scale of months/years). In fact, the phenomena of the variation of in-jectivity with injection water temperature and reservoir seismicity can be attributed to ther-mal stresses. In this paper a three-dimensional integral equation formulation is presented for calculating thermally induced stresses associ-ated with cooling of a fracture in a geother-mal reservoir. The procedure is then imple-mented in a computer program and is used to treat the problem of injection into an infinite fracture. The thermally induced stresses are calculated using actual field data for an injec-tion experiment. The resulting calculations are found to be consistent with those based on a semi-analytical solution as well as field observations. |