Mechanical properties of sandstone under in-situ high-temperature and confinement conditions  

作　　者：Liyuan Liu Juan Jin Jiandong Liu Wei Cheng Minghui Zhao Shengwen Luo Yifan Luo Tao Wang 

机构地区：[1]Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mines,University of Science and Technology Beijing,Beijing 100083,China [2]Key Laboratory of Oil&Gas Production,China National Petroleum Corporation,Beijing 100083,China [3]Research Institute of Petroleum Exploration&Development,PetroChina,Beijing 100083,China [4]Research Institute of Oil and Gas Technology,PetroChina Qinghai Oilfield Company,Dunhuang 736202,China [5]School of Future Cities,University of Science and Technology Beijing,Beijing 100083,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2025年第4期778-787,共10页矿物冶金与材料学报(英文版)

基　　金：financially supported by the Beijing Natural Science Foundation,China (No.JQ21028);the National Natural Science Foundation of China (Nos.52311530070,52278326,and 52004015);the Major National Science and Technology Project for Deep Earth,China (No.2024ZD1003805);the Project from PetroChina RIPED:the Study on the evolution law of Mineral Structure and Rock Mechanical Properties Under Ultra-High Temperature Conditions (No.2022-KFKT-02);the Fundamental Research Funds for the Central Universities of China (No.FRF-IDRY-20-003,Interdisciplinary Research Project for Young Teachers of USTB)。

摘　　要：Low-to medium-maturity oil shale resources display substantial reserves, offering promising prospects for in-situ conversion inChina. Investigating the evolution of the mechanical properties of the reservoir and caprock under in-situ high-temperature and confine-ment conditions is of considerable importance. Compared to conventional mechanical experiments on rock samples after high-temperat-ure treatment, in-situ high-temperature experiments can more accurately characterize the behavior of rocks in practical engineering,thereby providing a more realistic reflection of their mechanical properties. In this study, an in-situ high-temperature triaxial compressiontesting machine is developed to conduct in-situ compression tests on sandstone at different temperatures(25, 200, 400, 500, and 650℃)and confining pressures(0, 10, and 20 MPa). Based on the experimental results, the temperature-dependent changes in compressivestrength, peak strain, elastic modulus, Poisson's ratio, cohesion, and internal friction angle are thoroughly analyzed and discussed. Resultsindicate that the mass of sandstone gradually decreases as the temperature increases. The thermal conductivity and thermal diffusivity ofsandstone exhibit a linear relationship with temperature. Peak stress decreases as the temperature rises, while it increases with higher con-fining pressures. Notably, the influence of confining pressure on peak stress diminishes at higher temperatures. Additionally, as the tem-perature rises, the Poisson's ratio of sandstone decreases. The internal friction angle also decreases with increasing temperature, with 400℃ acting as the threshold temperature. Interestingly, under uniaxial conditions, the damage stress of sandstone is less affected by tem-perature. However, when the confining pressure is 10 or 20 MPa, the damage stress decreases as the temperature increases. This study en-hances our understanding of the influence of in-situ high-temperature and confinement conditions on the mechanical properties of sand-stone strata.

关 键 词：in-situ high temperature mechanical property thermal damage thermomechanical coupling 

分 类 号：TG1[金属学及工艺—金属学]