Characterizations on Geomechanical Properties of Colorado Shale Based on Well Logging and Laboratory Testing

摘要

Geomechancial properties of shale are essential to drilling operation and well design for thermal enhanced oil recovery. In this research, well logging and laboratory testing data are integrated to characterize the geomechanial properties of Colorado shale in Cold Lake area, Alberta, Canada. Density and sonic logs were applied to estimate the dynamic deformation modulus, Poisson’s ratio, internal frictional angle, and cohesion strength. Gamma ray log is applied to estimate shale’s clay content. Triaxial tests and confined torsion tests were conducted on samples to investigate transversely isotropic stiffness parameters and strength at quasi-static condition. The micro fabric characteristics of the clay shale were obtained from SEM images to investigate shale’s intrinsic anisotropy. Correlations between geomechanical properties derived from well logging and laboratory testing were generated. Values of deformation modulus and Poisson’s ratio derived from laboratory testing and well logging were correlated by introducing empirical coefficients. The anisotropic ratio in rock’s Young’s modulus is correlated to shale’s clay content. The values of log-derived internal frictional angle are consistent with the laboratory tested values. The shale’s clay content is found to be an important factor affecting the rock’s strength.