An Experimental Study on Monitoring the Hydraulic Fracturing Process of the Large-Scale Shale Sample by Integrating the Ultrasonic Multiple Scattering Wave Velocity Change and the Passive Acoustic Emission Technique
LI Dekang
XIE Fan
Abstract：This paper carries out an experimental study on monitoring the hydraulic fracturing process of large-scale shale sample under the true triaxial loading by using the active ultrasonic based method combined with a passive acoustic emission technique.The paper used ultrasonic multiple scattering waves to monitor wave velocity changes and a template matching based acoustic emission method to detect the acoustic emission activities during the experiment.The results suggest that integrating active and passive monitoring methods allows us to observe a decrease in wave velocity approximately 36 seconds before hydraulic fracturing breakdown.A minimum velocity reduction of 0.035(-3.5%)occurred four seconds before the breakdown.During the same stage,inactive acoustic emissions are observed 12 seconds before the breakdown,while a large number of acoustic emissions occur at the time of the breakdown.We also observe a 40 s-long logarithm velocity recovery process after the breakdown.Meanwhile,the acoustic emission shows a relatively rapid power-law decay.These findings demonstrate that integrating active and passive monitoring methods effectively characterizes the evolution of the medium during hydraulic fracturing.This provides valuable support for laboratory studies on shale gas exploration and risk assessment.
Keywords：Multiple scattering wavesAcoustic emissionVelocity changesTemplate matchingHydraulic fracturing
Publication Date：2025-12-30
Online Publishing Date：2025-12-15(First online date of this platform, not the publication date of the document)
Pages：7( 1-7 )