Tensile Fracture Propagation in Deep Coalbed Methane Layers Under Brazilian Test: A Quantitative Analysis Using Digital Rock Technology and Deep Learning-Based Image Segmentation
摘要
Tensile fracture propagation is a critical aspect of both coalbed methane exploitation and underground coal mining. A significant gap in the existing knowledge is the quantitative understanding of tensile fractures’ initiation and propagation within the context of the existing pore fracture network. This research addresses this gap using such cutting-edge technologies as deep learning, computed tomography (CT) scanning, scanning electron microscope (SEM), and mechanical loading under Brazilian Test conditions. Coal samples from the Ordos Basin of China underwent step-by-step loading, and CT scanning was conducted before and after each loading step. Then, the tensile fractures’ evolution was investigated. A deep learning technique was employed for accurate image segmentation. The developed models were transformed into a user-friendly Windows-based App, providing a valuable resource for fellow researchers. The analyses revealed insights into the initiation, propagation, extension, and growth of tensile fractures. Two-dimensional (2D) and three-dimensional (3D) analyses considered fracture length, aperture, density, and volume, leading to the formulation of relevant rock mechanical and geomechanical models. This research contributes valuable insights into the intricate interplay between natural fractures and tensile fractures’ dynamics based on the pore space evolution pattern. The findings have significant implications for coalbed methane extraction and coal mining.