Numerical study of thermo-mechanical effects on the viscous damage behavior of rock salt caverns

C. Zhu, X. Shen, C. Arson, A. Pouya

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

Abstract

Underground cavities in rock salt have received increased attention for the storage of oil, gas, and compressed air energy. In this study, the transition between secondary and tertiary creep in salt is determined by a micro-macro model: The initiation of grain breakage is correlated with the acceleration of viscoplastic deformation rate and with the initiation of damage at the macroscopic scale. Salt stiffness decreases when macroscopic damage increases, which allows predicting the evolution of the damage zone around salt caverns used for geological storage. After implementing the phenomenological model into the Finite Element Method (FEM) program POROFIS, two thermo-mechanical coupled stress paths are simulated to analyze stress concentrations and viscous damage around a 650-m-deep cavern in axisymmetric conditions. Numerical results indicate that, despite the pressurization or depressurization-induced temperature variation, internal gas temperature always tends to approach the primary surrounding rock mass value. The viscous deformation induced by thermo-mechanical couplings significantly affects the original stress field at the cavern wall and induces high damage at the most concave sections of the cavern. Results reveal the significant influences of idle time, gas pressure range, and injection and withdrawal cycles on stress, strain and temperature distributions in the vicinity of the cavern. More analyses are needed to confirm the influence of thermo-mechanical cycles of pressurization and depressurization, and to design long-term cavern operations.

Original languageEnglish (US)
Title of host publication51st US Rock Mechanics / Geomechanics Symposium 2017
PublisherAmerican Rock Mechanics Association (ARMA)
Pages1305-1313
Number of pages9
ISBN (Electronic)9781510857582
StatePublished - Jan 1 2017
Event51st US Rock Mechanics / Geomechanics Symposium 2017 - San Francisco, United States
Duration: Jun 25 2017Jun 28 2017

Publication series

Name51st US Rock Mechanics / Geomechanics Symposium 2017
Volume2

Conference

Conference51st US Rock Mechanics / Geomechanics Symposium 2017
CountryUnited States
CitySan Francisco
Period6/25/176/28/17

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geophysics

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