Seismic investigation of lithological controls on effective stress

The effective stress is an important concept for many subsurface engineering problems, where it represents the external load carried by the rock itself. It can be decomposed into two main components, which include the confining stresses and the pore pressure effects. The confining stresses can be estimated relatively easily with knowledge of the elastic properties. The pore pressure effects however, require knowledge of the Biot-Willis coefficient, which is a key component associated with the pore pressure term. To properly estimate the Biot-Willis coefficient, we require knowledge of the more fundamental building blocks of a rock mass that go beyond the elastic domain. These include the petrophysical properties from which components of the rock mass such as its pore space, frame and solid phase can be assembled from its constituent parts.