Geomechanical characterization by estimating the Vp/Vs ratio of sedimentary rock samples

Abstract

The velocity ratio V$_{p}$/V$_{s}$ and elastic parameters are effective quantities for describing various physical parameters and lithological properties of rock samples. Ultrasonic measurement was used to evaluate the V$_{p}$/V$_{s}$ ratio. Ultrasonic velocity estimation is widely used in the quantitative evaluation of rock materials. Ultrasonic P and S-wave travel times were studied in one direction of cylindrical core samples with a length and diameter of 100 mm. Wave velocity analysis was carried out on 20 crystalline drill cores taken at depths ranging from 10 m to 80 m. The cores were then tested for their ultrasonic velocity. The studied samples were also geomechanically characterized using ultrasonic testing. In this paper, the method used and a brief description of the measurement geometry are presented. The results of the calculations of P and S wave velocities, V$_{p}$/V$_{s}$ ratio, Young's modulus and Poisson's coefficient are given. Finally, the studied samples were geologically classified and the V$_{p}$/V$_{s}$ ratio was discussed.