An Analogical Method on Fractal Dimension for Three-Dimensional Fracture Tortuosity in Coal Based on Ct Scanning

Abstract

In this work, we have given an analogical method for estimating the fractal dimension for three-dimensional fracture tortuosity (3D-FT). The comparison and error analysis of analogical and rigorous methods on fractal dimension for 3D-FT were carried out in this work. The fractal dimension [Formula: see text] for 3D-FT from the proposed analogical method is the function of 3D fracture average tortuosity ([Formula: see text] and average fracture length ([Formula: see text]. The analogical method for estimating fractal dimension ([Formula: see text] with high accuracy indicates good consistency with the rigorous method ([Formula: see text]. The fractal dimension ([Formula: see text] from the rigorous method is the embodiment of the physical meaning of [Formula: see text]. The fractal dimension ([Formula: see text] from the analogical method is relatively convenient for calculating the premise of ensuring accuracy.

Fractal Evolution Characteristics on the Three-Dimensional Fractures in Coal Induced by CO2 Phase Transition Fracturing

“…The fracture surface area is the total area of the internal surface of the 3D fractures in coal [28,29]. Therefore, the number, length, volume and surface area of fractures are key parameters that reflect the 3D fractures [29][30][31]. The current research on the 2D fracture structure of CO 2 -PTF coal is not enough to fully reveal the 3D fracture evolution characteristics of CO 2 -PTF coal.…”

Effects of Liquid CO2 Phase Transition Fracturing on Methane Desorption of Coal

“…Coal is a classical porous media with pores and fractures, , and CBM is mainly adsorbed in the coal matrix and nanopores . Thus, the structure of pores and fractures in coal influences the transport capacity of CBM. − The permeability and desorption efficiency jointly dominate the CBM productivity . After the LCPTF treatment, the structure of the pores and fractures in the coal was altered as the pathways and channels for the desorption and transport of CBM .…”