Microphysical Modelling of Frictional Slip in Hydrothermal Conditions

Cheng Mei, John W. Rudnicki

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Injection of fluids for geothermal stimulation has often caused seismic events that have raised concern and resulted in discontinuing the operations. Consequently, a safe and effective geothermal operation requires an assessment of the potential for induced seismicity. Rate and state friction (RSF) is well-established as a robust description of rock friction. It is, however, strictly empirical and extension to hydrothermal conditions relevant to geothermal stimulation is problematic. We extend a microphysical model to hydrothermal conditions by incorporating thermally activated processes in fault gouges. We use a simple spring-slider model to simulate steady-state friction at a typical range of temperatures and load-point velocities. Numerical simulations show that, consistent with experimental observations, the simulated steady-state friction of granite gouges in wet conditions rises slightly with temperature, and the friction rate parameter (a − b) transitions from velocity-strengthening at low temperatures to velocity-weakening behaviors at high temperatures of about 300C. This transition indicates the possibility of change from stable to unstable (seismic) slip near this temperature. These results also suggest that the dominant deformation mechanisms may evolve from frictional granular flow with intergranular pressure solution at low temperatures to grain boundary sliding (GBS) with solid-state diffusion creep at high temperatures.

Original languageEnglish (US)
Title of host publication57th US Rock Mechanics/Geomechanics Symposium
PublisherAmerican Rock Mechanics Association (ARMA)
ISBN (Electronic)9780979497582
DOIs
StatePublished - 2023
Event57th US Rock Mechanics/Geomechanics Symposium - Atlanta, United States
Duration: Jun 25 2023Jun 28 2023

Publication series

Name57th US Rock Mechanics/Geomechanics Symposium

Conference

Conference57th US Rock Mechanics/Geomechanics Symposium
Country/TerritoryUnited States
CityAtlanta
Period6/25/236/28/23

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

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