Numerical simulation of gas flow in artificial fracture coal by three-dimensional reconstruction based on computed tomography

The influences of spatial geometric shape and position of a fracture on gas seepage were analyzed to explore the law of gas flow in the fracture structure of coals. First, artificial fracture surfaces with different shapes were preset in the computed tomography (CT) image. A coal reconstruction model with a single artificial fracture with different shapes and angles was established by translating the artificial fracture plane using three-dimensional reconstruction technology. Finally, the internal gas seepage law was analyzed together with the finite element method. The simulation on the same spatial shape of the fracture structure demonstrated that the seepage velocity at the coal section did not show evident variation law with the angle. Based on further extraction of the penetration velocity on the artificial fracture section, the penetration velocity increased with the expansion of the fracture angle under the same fracture shape. The penetration velocity on different shapes of the fracture surface increased with the fracture edges (from square to circular) under the same angle.