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在三轴围压容器内对泥岩、粉砂岩、砂岩和杂砂岩中的弹性波速度、衰减和渗透率进行了测量,并对样品作了显微组构分析。实验发现,由于砂岩的孔隙率大,矿物颗粒的分选度和磨圆度较好,颗粒间孔隙的连通性很好,其渗透率最高;粉砂岩中晶体颗粒尺寸比砂岩的小,颗粒间的孔隙也较小,连通性受到影响,因此渗透率比砂岩的低;泥岩的渗透率更低,因为它的矿物颗粒更细小且固结性较差,很容易将连通的孔隙堵塞;杂砂岩是由分选性差、未经磨圆的碎砾通过基质胶结形成的,孔隙间的连通性很低,它的渗透率最小。随着围压和轴向差异应力的变化,四种样品中的波速、衰减和渗透率均发生不同形式的变化,反映了岩样组构特别是微裂隙的变化情况。
The elastic wave velocity, attenuation and permeability in mudstone, siltstone, sandstone and miscellaneous sandstone were measured in a three-axis confining pressure vessel, and the microstructure of the sample was analyzed. The experiment shows that because of the porosity of sandstone, the sorting degree and rounding degree of mineral particles are good, the connectivity of intergranular pores is very good, and the permeability is the highest; the size of crystal particles in siltstone is smaller than that of sandstone, Permeability is lower than that of sandstone; permeability of mudstone is lower because of its finer grain size and poorer consolidation, and it is easy to plug the interconnected pores; miscellaneous sandstone It is formed by matrix cementation of poorly sorted, unround gravel, with low connectivity between pores and minimal permeability. With the variation of confining pressure and axial difference stress, the wave velocity, attenuation and permeability of the four samples all changed in different forms, which reflected the changes of rock structure, especially the microcracks.