【摘要】 在实验室超声波频率下 (纵波主频为 70 0kHz、横波为 2 5 0kHz)对层理发育的页岩和泥岩的各向异性进行了研究 ,给出了在干燥和油饱和条件下 ,样品不同方向上纵、横波速度以及各向异性参数随压力的变化规律 .用X 射线衍射和扫描电镜分析了样品中引起各向异性的原因 ,指出平行于层理定向排列的粘土矿物和微裂隙是使样品显示出强弹性各向异性的内在原因 .随着压力的增高微裂隙逐渐闭合 ,样品的各向异性程度减弱 .孔隙流体的存在增强了孔隙 (裂隙 )的刚度 ,减弱了各向异性随压力增大而减小的趋势 .更多还原

【Abstract】 The velocity anisotropy is examined in laminated shale and mudstone under the laboratory ultrasonic frequency. The variation patterns of wave velocity in different directions as a function of confining pressure are also presented for dry and oil-saturated situations. Using the X-ray diffraction technique and electron microprobe imaging, we make analysis and conclude that the clay minerals and microcracks are the intrinsic factors that result in such strong anisotropy in rock samples. With the increasing confining pressure, microcracks are gradually closed, which low the anisotropy. Pore fluid increases the pore rigidity thus decreases the tendency of anisotropy change with confining pressure.更多还原