Effects of natural micro-fracture morphology, temperature and pressure on fluid flow in coals through fractal theory combined with lattice Boltzmann method

The fluid flow behaviors during the production of coalbed methane (CBM) are generally restricted by pre-existing natural fractures in coal seams. To better understand effect micro-fracture morphology on capability, nine coals collected from Ordos Basin were subjected to optical microscope observations obtain micro-fractures morphology. And then, box-counting method (BCM) was used quantify complexity network planar distribution. Besides, lattice Boltzmann (LBM) adopted simulate complex under different pressures and temperatures. Finally, factors affecting capability elaborated. results show that present dendritic, reticular, filamentous orthogonal structures. has a remarkable impact behavior, which presence dominant channels with length ~498.26 ?m width ~10.96 significant contribution permeability, while normally is not conducive flow. fractal dimension extracted varies 1.321 1.584, permeability calculated LBM 0.147 0.345 D; contrast other studies, non-monotonic change, an inverted U-shaped, observed. Moreover, decreases as pressure increases increasing temperature due physical properties matrix. Therefore, this work may contribute understanding process hydrofracturing hydrothermal methods for improving CBM reservoirs enhancing recovery.