Testing of Reservoir Core Samples Based on 3D Acoustic Tomography: Principles and System

This study addresses the challenges of single-dimensional and low-precision acoustic monitoring in indoor reservoir rock cores by developing a high-precision acoustic emission (AE) localization and three-dimensional (3D) elastic parameter inversion method and system. The innovative method introduces time-frequency spectral envelope characteristics as a feature function to perform secondary corrections on the arrival times of waveform signals in cross-correlation algorithms, significantly improving localization accuracy. It synergizes active and passive source signals to achieve 3D inversion. The core workflow includes: localization using waveform cross-correlation algorithms, optimizing time-window extraction; extracting spectral envelopes, establishing an initial velocity field, solving the eikonal equation, and calculating the 3D elastic modulus and Poisson’s ratio. Experimental results demonstrate that the accuracy achieves over 50% improvement in AE event localization, while simultaneously obtaining high-precision 3D elastic parameter distributions. This technology overcomes the limitations of conventional one-dimensional acoustic velocity testing, providing reliable technical support for reservoir monitoring, fracture identification, and production strategy optimization in oil and gas reservoir development. It holds significant importance for enhancing energy extraction efficiency and safety.