A speckle technique recently developed for transient phenomena analysis is applied to the study of dynamic properties of petroleum wells. It is shown that the samples (proceeding from the Orinoco Belt, Venezuela) actually give rise to random speckle patterns when illuminated with a laser beam. Transverse displacements of the sample’s surface can then be measured by classical speckle photography. When the root mean square of the phase and intensity variations in the scattered light are small with respect to the corresponding mean values, line of sight displacements of the surface can also be measured by means of a simple modification of the original technique.
G. Da Costa, G. Guerri, and J. Tani, "Procédé de mesure interférométrique utilisant le speckle et son application à l’instrumentation pétrolière," Appl. Opt. 16, 1754-1754 (1977)