Pore-scale simulation of effects of coal wettability on bubble-water flow in coal cleats using lattice Boltzmann method

Abstract

(Huilin Xing) We study the effects of coal wettability on gas bubble/water two-phase flow behaviour in micro-cleats of the coal seam gas reservoir using a free energy based two-phase lattice Boltzmann model. The model is validated by comparison with analytical results and published results, and good agreement is achieved in general. Then we use this model to simulate bubble-water flow in both smooth capillary and a capillary with a narrow throat to systematically study the influences of contact angle, capillary pressure and bubble size on the flow behaviour. The simulation results indicate that both the bubble size and contact angle have significant impacts on the flow capacity of bubble and water, especially in a channel with a narrow throat. A decrease in water flow rate is observed when larger bubbles occur, and the water flow rate increases when the gas wettability becomes stronger. The bubble flow dynamics significantly influence the drainage of water and the further gas production.

Application of Lattice Boltzmann Approach for Teaching a Rock Mass Seepage Mechanics Course

“…To address these challenges, the introduction of advanced theoretical analysis techniques is necessary to provide students with a more intuitive and accurate understanding of seepage laws and mechanisms. The extensively exploited unconventional rock masses exhibit complexity, making the lattice Boltzmann (LBM) simulation method increasingly prevalent in addressing microscale seepage issues and intricate channel networks [3][4][5][6][7][8][9][10][11][12][13][14][15]. The LBM approach offers flexibility in handling fluid-boundary interactions, a feat challenging for traditional numerical methods.…”

Nuclear Magnetic Resonance Experiment on the Influence of Confining Pressure on Spontaneous Imbibition of Water in Coal

“…Coalbed methane is a disaster gas threatening coal mine safety production, but it is also a natural, efficient, and clean energy. − The development and utilization of coalbed methane is significant in maximizing clean energy and improving coal mine safety production conditions. Hydraulic measures are important means of coal seam gas mining. − When hydraulic measures, such as water injection, are taken to the coal seam, spontaneous imbibition occurs inside the coal body, − and water will soften and moisten the coal body, , induce fracture in coal body, promote gas desorption, and eventually suppress dust and prevent gas outburst and rockburst. , The complex macro bedding and micropore structures of the coal body also affect water imbibition in the coal body. − Therefore, the microscopic pore structure characteristics of the coal body in a loaded environment and spatial distribution and evolution characteristics of water during the imbibition process should be investigated to study the mechanism of deep CBM water injection and extraction.…”