Deciphering the Tensile Fracturing Process Using Synchronized Acoustic Emission and High-Speed Digital Image Correlation

Shan Wu, Hui Yang, Boyang Su, Guanglei Cai, Qi Zhao

Abstract: Tensile fractures play a critical role in forming effective production channels during hydraulic fracturing. Although microseismic monitoring is commonly used to observe fracture growth, the direct relationship between microseismic events and tensile fracture remains insufficiently understood. To address this gap, we conducted a tensile fracturing experiment that simultaneously recorded microseismic signals (acoustic emissions, AEs) and high-speed photographic images. A synchronization circuit was employed to align the 10 MHz AE recordings with high-speed images captured at 200,000 frames per second, enabling the precise recording of millisecond-scale fracture propagation. This synchronization setup enabled us to precisely record fracture propagation and AEs within a microsecond scale period. Our results reveal that AE events correlate spatially with the macroscopic tensile fractures. We observed a microsecond-level time delay between the fracture propagation and the clustering of AEs. This delay indicates that the clustering of AEs is related to the fracture nucleation process, while the high-speed photography records the coalescence and growth of tensile fractures. Considering the temporal and spatial alignment between the AEs and the tensile fractures, it is evident that microseismic monitoring primarily captures the early stages of crack formation. Our research indicates that current microseismic monitoring results lack interpretation of the relationship between the nucleation stage and macroscopic fractures, as well as the relationship between microseismic clouds and fracture networks.

External IDs:doi:10.1007/s00603-025-04826-9