EXPERIMENTAL STUDY ON THE RELATIONSHIP BETWEEN ROCK FRACTURE TOUGHNESS AND ACOUSTIC VELOCITY

The fracture mechanics is important one of hydraulic fracturing study. Basedon the current hydraulic fracturing model, this paper proposes a simple method for determining the rock fracture toughness, which consists of hollow thick wall cylinder core with internal hydraulic pressure. A preliminary set of experiments has been performed on sandstone and shale. The relationships among rock fracture toughness, acoustic velocity and dynamic elasticity modulus have been established. Results show that fracture toughness has a good linear correlation with longitudinal wave velocity, shear wave velocity and dynamic elasticity modulus, It lays a foundation for predicting rock fracture toughness by using logging data from field.