USE OF ACOUSTIC EMISSION IN ROCK FORMATION ANALYSIS

摘要

The invention relates to a method of determining a characteristic of a material selected from rock formation and cement, which material surrounds a borehole containing a fluid. The method comprises positioning an acoustic sensor at a selected position in the borehole, the acoustic sensor being suitable to provide signals representing acoustic emission from said material, applying a selected pressure to the fluid thereby inducing mechanical stresses in said material, said stresses inducin g acoustic emission from said material. The sensor is induced to detect the acoustic emission and to provide a signal representing the acoust ic emission. The characteristic is determined from said signal and from the pressure applied to the fluid.