煤粉问题是制约煤层气井连续稳定排采的关键因素之一。排采实践表明，产气初期阶段出煤粉浓度远高于排水阶段，导致产气量波动和频繁卡泵，在煤粉防控时应对其特别关注。在产气初期阶段，煤层裂隙内流型以泡状/段塞流为主，液相中含有一系列移动气泡。目前，针对移动气泡诱发裂隙内煤粉启动-运移机理的研究还鲜有报道。本项目基于毛细力学、水动力学、扩展DLVO理论和JKR接触理论，构建移动气泡诱发裂隙内煤粉启动力学模型，揭示煤粉启动微观力学机制；采用考虑毛细力作用的CFD-DEM耦合法，开展移动气泡诱发裂隙内煤粉运移数值模拟，并结合可视化实验，明确煤粉运移形式及动态运移规律。在理论分析、数值模拟和可视化实验基础上，进一步探究气-水界面张力和煤粉/裂隙面润湿性对煤粉启动-运移的影响。项目研究可为产气初期阶段出煤粉预测与防控提供理论指导，对经济高效开发煤层气具有重要意义。

The issue of coal fines is a key factor restricting the continuous and stable drainage of coalbed methane (CBM) wells. Drainage practice reveals that the concentration of coal fines produced in the early stage of gas production is much higher than that in the dewatering stage, leading to the fluctuation of gas production and frequent stuck pump. Special attention should be paid to this case in controlling coal fines. In the early stage of gas production, the flow pattern in coalbed fractures is dominated by bubble/slug flow, with a series of moving bubbles contained in the liquid phase. Till date, the mechanisms underlying the incipient motion and migration of coal fines induced by moving bubbles in fractures have rarely been reported. Based on the capillary mechanics, hydrodynamics, extended-DLVO theory, and JKR contact theory, a mechanical model of incipient motion of coal fines induced by moving bubbles in fractures is built, to illustrate the micro-mechanical mechanisms of incipient motion of coal fines. The CFD-DEM coupling method considering the effect of capillary force is used to perform the numerical simulation of coal fines migration induced by moving bubbles in fractures, to reveal the mode of coal fines migration and the law of its dynamic migration by integrating visual experiments. Based on theoretical analysis, numerical simulation, and visual experiments, the effect of gas-water interface tension and fines/fracture surface wettability on incipient motion and migration of coal fines is further explored. This project study can provide theoretical guidance for predicting and controlling the coal fines to be produced in the early stage of gas production, which is of great significance for the economical and efficient exploitation of CBM.