| Title | The role of pore fabric on the strength and seismicity of geothermal reservoir host rocks |
|---|---|
| Authors | Fernanda MERCHÁN, John BROWNING, Gloria ARANCIBIA, David HEALY, Valentina MURA, Diego MORATA |
| Year | 2025 |
| Conference | LATAM Geothermal Congress |
| Keywords | Aspect ratio, Induced seismicity, Mechanical anisotropy |
| Abstract | The strength of geothermal reservoir host rocks, and hence their propensity to fracture and generate permeable fluid networks, is conditioned, in part, by mechanical anisotropy. Vesicular dacitic lavas from the Nevados de Chillán Volcanic Complex (NCVCH) exhibit populations of variably elongated and preferentially aligned pores. It has been shown that compressive strength varies substantially with loading direction in basaltic lavas containing preferred pore alignments. In particular, when stress is applied parallel to the major axis of the preferentially aligned pores, rock strength decreases due to stress concentrations at the pore tips, promoting nucleation, propagation and coalescence of fractures. This behavior suggests that, in a geothermal reservoir, the directions of maximum permeability may be controlled by the relation between the geometry of pores and the direction of local stresses. To quantify these effects, uniaxial compression tests (UCS) were conducted on cylindrical co |