Evaluation of Cambay shale Cambay basin, India using geo-mechanical properties

摘要

Shale formations have laminated structures with significant variations in mechanical properties along the orientations of the bedding plane. This results in anisotropy, which is an important issue in exploration. The goal of the study is to analyse the physical properties of two core samples from Cambay basin, Gujarat (phase composition, crystallographic preferred orientation, crystal structure and texture) and to compute the Thomsen parameters using synchrotron X-ray diffraction method. To analyse complicated diffraction images resulting from different clay minerals (illite and smectite, kaolinite, quartz, siderite, feldspar), Rietveld refinement method was used. Our results show that elastic anisotropy resulting from crystallographic preferred orientation of the clay particles can be determined quantitatively. This study also provides a possible way to measure anisotropy mathematically.