Relationship between Acoustic Body Waves and in Situ Stresses around a Borehole

M-29 RELATIONSHIP BETWEEN ACOUSTIC BODY WAVES AND IN SITU STRESSES AROUND A BOREHOLE ANDRÉ ROUSSEAU CNRS-Université Bordeaux 1 351 cours de la Libération 33405 Talence cédex France 1 Summary This paper shows that there are three types of shape of acoustic body waves propagating inside competent formations crossed by a borehole. This fact is connected to the modification undergone by the area located around a well after drilling in relation to the in situ state of stress. The multiple waves inside the modified area allows to calculate its size which depends on the ratio between vertical stress (equivalent to ground