摘要：In this paper, a systematic experimental analysis of the rock mechanics properties of interbedded tight sandstone and shale formations was conducted. The research results can provide basic data for drilling and completion engineering. The study shows that the stress/strain curves of interbedded tight sandstone and shale under formation conditions can be divided into four stages: initial compaction stage^linear elastic extension stage ^nonlinear plastic extension stage^post-peak residual strength stage. The increase of shale content can often reduce the triaxial strength of the rock sample, and increase the axial and circumferential strain before failure, and the circumferential strain is smaller than the axial strain. The increase in shale content also increases the length of the strain ductile section, so that shale can undergo longer plastic creep behaviors and accumulate large stresses compared to tight sandstones. Therefore, the stress in the shale is often greater than the adjacent sandstone layer. Tight sandstones with high meteorite debris content tend to have higher triaxial strength and lower strain under formation conditions. The yield strength ratio of in- terbedded tight sandstone and shale samples is roughly between 60-70% with little difference. The yield strength of shale is generally smaller than that of sandstone. The proportion of plastic strain of tight sandstone is 20-35%, while the proportion of plastic strain of shale is 30-45%. Finally, a conversion model of dynamic and static elastic parameters and shear parameters suitable for the target layer of the study area was obtained.
关键词：Tight sandstone;shale rock;elastic parameters;shear parameters;conversion model
