【摘要】 页岩地层垂向岩矿组合变化大，页岩气开采需要对储层进行大规模人工水力压裂改造。笔者等基于样品的全岩X-射线衍射分析，通过对不同岩矿组合的3块页岩试样进行流—固耦合物理模拟实验，获得了3点认识，反映了不同岩矿成分的页岩在不同条件微裂缝与渗透率的变化特征，以及碳酸盐矿物含量高时的影响。这一实验对于研究页岩储层在压裂过程中的变化具有探索性，对于页岩气生产具有重要的参考意义。更多还原

【Abstract】 Objectives: The vertical mineral combination of shale formations varies greatly, and shale gas exploitation requires large-scale artificial hydraulic fracturing. During the fracturing transformation of shale gas exploitation reservoir, the regularity and mechanism of permeability change are of great significance to the design of fracturing engineering of shale gas. Methods: The author and others conducted fluid—solid coupling physical experiments on three shale samples with different mineral combinations based on the whole-rock X-ray diffraction analysis of samples. Results: Shales with different rock and mineral compositions exhibit different characteristics of microfractures and permeability changes under different conditions. Both siliceous and carbonate minerals can be used as brittle minerals, but there are significant differences in their brittleness characteristics. Conclusions: Based on the comprehensive analysis, three insights were obtained:(1) During the loading process, the presence of small stress platforms in the stress—strain curve can indicate the formation of microfractures in the sample, which is the intrinsic mechanism of permeability change;(2) The permeability of different mineral combination shale samples varies significantly with the axial pressure. The essence is the combination of minerals, and the brittleness of shale samples is different. During the pressurization process, the development of fractures is different, resulting in different permeability changes;(3) Rickman’s mechanical brittleness index can only better reflect the brittleness characteristics determined by siliceous minerals. While when the content of carbonate minerals(calcite) is high, Rickman’s mechanical brittleness index is difficult to effectively reflect the brittleness characteristics.更多还原