Abstract：The velocity and amplitude are necessary parameters when using P-wave to predict the fractur-al reservoir and it is necessary to know the relationship between the fractural density and velocity/amplitude in practical data processing. In lab, the fractural model is simulated by embedding the circle and thin coin into base material, fabricating 9 fractural model with fractural densities from 0 % to 12%; and using ultrasonic transducer with 4 frequencies to test P-wave velocity and transmission energy in the directions parallel and vertical to fracture. getting the curves of fractural density vs P-wave velocity and amplitude. The experiments showed when P-wave propagates along the fractural direction, the variation of fractural density has little influence on velocity: only 2% variation of velocity when the fractural density is increased by 12%; when P-wave propagates vertical to fracture,the velocity is decreased by half in comparison with parallel to fracture. Along with the increase of fractural density, the decreasing tendency of P-wave amplitude is relative not only to fractural density, but also to frequency. The experimental results quantitatively gave the influence of fractural density and frequency on P-wave parameters in fractural medium.
