Numerical Simulation of Gas Flow Based on Three-dimensional Reconstruction Using Computed Tomography

摘要

In order to obtain the real physical model characterizing the pore and fissure structures of coal rocks and explore the seepage rules of coalbed methane (CBM) using numerical simulation, we proposed a sequential study method from real coal model to coal CAD model to coal finite element model. The coal sample from Changzhi Shanxi was scanned using high precision μCT225kVFCB CT system and the obtained CT data were subject to threshold segmentation using the compensated DTM method. The real model of coal is converted to the CAD model of coal by reverse engineering, Lastly, The coal body finite element model established by Ansys as an example, the seepage of coal gas were simulated, analyzed coal pore pressure and velocity distribution, the permeability coefficient of X, Y, along the Z direction and calculation. Calculation results show that the micro scale (< 100 μm) coal permeability anisotropy, which is affected by coal body structure is obvious. The numerical simulation results show that with the increase of the pressure gradient at the micro scale, the penetration velocity of the gas in the fracture section is gradually increased.