Introduction to this special section: Practical applications of anisotropy

Abstract

The use of seismic anisotropy is a topic that has evolved dramatically in the last 25 years in the oil and gas industry. Even though physicists who study waves and vibrations in solids have taught us that elastic properties of rocks should be described by a complex set of functions and parameters, many years of seismic data processing were conducted assuming that the velocities in the subsurface rocks were isotropic, and that the shear modulus was zero (that the rocks could be treated as “a liquid”). “Isotropic” means that the value measured (e.g., velocity) is the same in all directions (whether you consider angles of incidence or source-receiver azimuths) for a rock volume of interest.