Rock physics of shales: applications in geomechanics

Abstract

Shale formations act as barriers in carbon capture and storage（CCS）and serve as seal rocks in conventional oil and gas fields. Understanding their elastic properties is essential for effective subsurface evaluation and drilling. One of the notable elastic properties of shale formation is strong anisotropy, which is influenced by the anisotropy and arrangement of clay minerals. The impact of this anisotropy on seismic response has been widely discussed, highlighting the importance of considering anisotropy in seismic data analysis. However, the influence of anisotropy in the field of geomechanics has received less attention, and the pitfalls of assuming isotropy in analysis have not been adequately addressed. In this presentation, I first introduce the elastic properties and rock physics of shales. Subsequently, I discuss the effects of anisotropy on geomechanical analysis and emphasize the issues associated with assuming isotropy in such analysis. Lastly, I address the challenges of implementing geomechanical analysis that considers anisotropy in real-field contexts, and I discuss the role of rock physics in this setting.