Analysis of deformation and failure of sediment particle-surrounding rock structure of salt cavern gas storage under the coupled action of temperature and pressure

• Published in: Geoenergy Science and Engineering Vol. 243; p. 213330
• Main Authors: Zhang, Huabin, Yu, Haoyi, Wanyan, Qiqi, Ran, Lina
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2024
• Subjects: FLAC3D-PFC3D coupling; Gas injection and production; Salt cavern gas storage; Sediment particles; Thermo-mechanical coupling; Salt cavern gas storage; Sediment particles; Thermo-mechanical coupling; FLAC3D-PFC3D coupling; Gas injection and production
• ISSN: 2949-8910; 2949-8910
• DOI: 10.1016/j.geoen.2024.213330

When gas is injected or produced in the gas storage of salt cavern, the different effects of thermal stress, gas pressure, sediment particles and brine pressure on the cavity wall of salt cavern may cause large deformation and damage in the surrounding rock, which threatens the safe and stable operation of the gas storage of salt cavern. Therefore, based on FLAC3D-PFC3D coupling method, a numerical model of salt cavern gas storage with sediment particles in consideration of temperature was constructed, and the influence of injection-production time effect, sediment particle size and initial porosity on the deformation and failure of sediment-surrounding rock structure is studied. The results show that the tensile contact force chain of sediment is sensitive to the particle size of sediment, but insensitive to the initial porosity of sediment and injection-production conditions; during gas production, the larger the particle size and initial porosity of sediment particles, the greater the vertical displacement of shallow sediment particles, and the opposite results are obtained during gas injection. With the progress of gas production and gas injection, the absolute value of vertical displacement of the roof of the salt cavern increases gradually, and the plastic failure range of surrounding rock expands; for gas production process, the larger the particle size and initial porosity of sediment, the smaller the algebraic value of vertical displacement of surrounding rock at the top of cavity and the smaller the plastic failure range of surrounding rock. For the gas injection process, the larger the particle size and initial porosity of the sediment, the larger the algebraic value of the vertical displacement of the surrounding rock at the top of the cavity and the larger the plastic failure range of the surrounding rock. The results can provide reference for the reasonable setting of injection-production operation parameters of salt cavern gas storage and ensure the safe and stable operation of underground salt cavern gas storage (USCGS). •The complex internal dynamic boundary conditions of salt cavern gas storage are simulated.•Thermo-mechanical coupling of continuous-discontinuous coupling model.•Deformation and failure analysis of sediment particles and surrounding rock.•The effects of injection and production time, sediment particle size and initial porosity.•The heat transfer law between sediment particles and surrounding rock.