The mediate-low maturity continental shale oil reservoir in the 7th member of the Triassic Yanchang Formation is one of the main zones for shale oil exploration and development in Ordos Basin, China, but the seismic response mechanism of the reservoir remains unclear. Therefore, developing a new method for “sweet spot” seismic prediction combined with rock physics is necessary. To determine the petrophysical characteristics of continental shale in the 7th member of the Yanchang Formation in the study area, a series of tests, such as a systematic acoustic test on shale oil samples in the target segment, X-ray diffraction analyses, analysis of thin optical sections, and scanning electron microscopy, were conducted to summarize the patterns of seismic elastic property changes. Results show that the shale oil samples of the 7th member of the Yanchang Formation are primarily composed of lithic feldspar sandstone with feldspar dissolution and intergranular pores, widespread micron pores, and throats. Such composition indicates a positive correlation between porosity and permeability. The velocities of the samples are affected by their porosity and mineral composition. Velocity increases with the increase of the calcium content and decreases with the increase of the clay content, indicating a negative correlation with the porosity and total organic carbon (TOC) content on the condition of the same rock structure (quartz skeleton or clay skeleton). The elastic properties of the rock are horizontally isotropic (T1 medium), and the velocity is vertically anisotropic. In addition, the directional arrangement of clay controls the anisotropy of rock velocity. TOC is mainly distributed in the primary intergranular pores, and it has no contribution to the anisotropy of rock velocity. The results of this paper can provide a reference for the seismic prediction of continental shale oil reservoirs in the 7th member of the Yanchang Formation.

三叠系延长组七段中低成熟度陆相页岩油储层是我国鄂尔多斯盆地页岩油勘探开发的主要区域之一，但该储层的地震响应机制尚不清楚。因此，开发一种结合岩石物理的“甜点”地震预测新方法是十分必要的。为确定研究区延长组七段陆相页岩岩石物理特征，开展了目标段页岩油样品系统声学测试、X射线衍射分析、薄层分析等一系列测试。通过光学剖面和扫描电子显微镜，总结了地震弹性特性变化的模式。结果表明，延长组七段页岩油样品主要为岩屑长石砂岩，伴有长石溶蚀及粒间孔、广泛分布的微米孔和喉道。这种成分表明孔隙率和渗透率之间存在正相关关系。样品的速度受其孔隙度和矿物成分的影响。速度随着钙含量的增加而增加，随着粘土含量的增加而减小，表明在相同岩石结构（石英骨架或粘土骨架）的条件下，其与孔隙度和总有机碳（TOC）含量呈负相关。岩石的弹性特性在水平方向上是各向同性的（T1 介质），而速度在垂直方向上是各向异性的。此外，粘土的定向排列控制着岩石速度的各向异性。TOC主要分布在原生粒间孔隙中，对岩石速度的各向异性没有贡献。本文研究成果可为延长组七段陆相页岩油藏地震预测提供参考。