Stress Path of Heterogeneous Rock Layers within the Subsurface

This paper presents a three-dimensional analytical solution for stress path within and around a porous rock formation upon depletion. The depletion profile is assumed to be axisymmetric, and the depleted rock layer resides in between two impermeable rock layers. The mechanical properties of the porous and confining strata are different. Variations in the in-situ stress value or orientation are obtained and presented. Strong dependencies of the in-situ stress change on stiffness contrast between the depleted and burden rocks, as well as the aspect ratio of depleted rock volume, are discussed. Uniaxial strain models are shown to fall inadequate of predicting the correct reservoir stress path.