Engineering Commons^™

Size Effect And Anisotropy On The Strength Of Shale Under Compressive Stress Conditions, Yun Zhao

Graduate Theses, Dissertations, and Problem Reports

The underground coal mines in the Appalachian region report the highest rate of roof falls in the United States. The immediate roof of these mines is mostly composed of shale. The in-situ strength of shale is necessary for designing roof support to prevent roof falls. Estimating the in-situ strength of shale requires the knowledge of both size effect and anisotropy. This research used literature review, theoretical analysis, numerical modeling, and laboratory experiment to systematically investigate the size effect and anisotropy of shale strength under compressive strength conditions.

Literature review involved a comprehensive summary of previous research on the size effect …

Impact Of Natural Fracture Induced Elastic Anisotropy On Completion And Hydraulic Fracturing Designs, Emre Can Dundar

Graduate Theses, Dissertations, and Problem Reports

Shale has been usually recognized as a transverse isotropic (TI) medium in conventional geomechanical log interpretation due to its laminated nature. However, when natural fractures (NFs) exist in the rock body, additional elastic anisotropy can be introduced, converting Shale to an orthorhombic (OB) medium. Previous study illustrates that treating the naturally fractured shale rock as a TI medium by ignoring the NF-induced anisotropy can cause the erroneous estimation of the geomechanical properties (i.e. Young’s modulus, Poisson’s ratio, brittleness index, and etc.) and in-situ stress. In this paper, the study is extended to quantify the impact of NF-induced elastic anisotropy on …