Improvement and upgrade of elastic modulus testing system under seismic frequency band

Obtaining the elastic modulus under seismic frequency band is an important task for oil and gas exploration. Specifically, it aids in quantitative interpretation of seismic data and characterization of the propagation of seismic waves. We have previously built a testing system based on the stress-strain measurements under seismic frequency, from which the Young's modulus, Poisson' s ratio and attenuation were successfully derived from 4,38 mm cores. However, the previous system faces challenges with thinner cores (phi 25 mm) which are generally used for measuring physical parameters (porosity, permeability, etc.) and ultrasonic longitudinal/transverse wave velocities. In this paper, we proposed improvement to the elastic modulus test system and the strain acquisition system (Wheatstone bridge). The reliability and accuracy of the low-frequency experiments on 4,25 mm cores were demonstrated by numerical simulations and calibration experiments (Aluminum and Lucite). The results show that the elastic parameters of the dry and inflated/aerated rock samples are consistent in the low and ultrasonic frequency bands, thus verifying the reliability of the improved measurement system. We have proven that he improved seismic frequency band elastic modulus test system can be an effective tool for quantitative characterization of the elastic dispersion of fluid-containing rocks. Moreover, the experimental results can not only be applied to production practice, but also provide an important experimental basis for testing and revising the rock physics model.