为系统研究煤层气井中多相流条件下煤粉启动-运移规律，以捞砂煤粉为研究对象，通过控制不同相流（液固两相、气液固三相）控制煤粉产出，开展多相流条件下不同粒径（小于0.075 mm、0.075～0.25 mm、0.25～0.85 mm、大于0.85 mm）煤粉启动-运移试验模拟，分析流量、压差、管道倾角、粒度等因素对煤粉启动-运移的影响。

研究结果表明：液固两相流下，随着液体流量逐渐增大，煤粉由静止状态向滑动—间歇滚动—滚动—层移—层移+悬移—悬移状态逐渐过渡。煤粉粒径越小，管道倾斜角度越小，启动流量越低；流量与压差呈现很好的线性关系，并受管道倾角影响；煤粉的粒径和管道倾角对煤粉的启动-运移难易程度具有重要影响，但二者的影响较为复杂，不同粒径煤粉的启动-运移流量与管道倾角之间并非简单的线性关系；不同角度下煤粉颗粒粒径（除大于0.85 mm大颗粒煤粉外）与启动流量关系可用一次线性关系表征，同时方程也可用于预测特定管道倾角下不同粒径煤粉对应的启动流量。气液固三相流下，煤粉启动-运移主要控制因素为流型，而流型受气液流量比和管道倾角影响，主要包括气泡流、塞状流、分层流、波状流、弹状流等流型，各流型携粉运移能力为气驱水分层流＞弹状流＞塞状流＞气泡流＞分层流；随气液流量比增大，压差先快速减小再趋于平缓，最终微弱反弹，管道倾斜角度越小，压差下降越快。

In order to systematically study the pulverized coal start-transport law under multi-phase flow conditions in coalbed methane wells, this paper took sand pulverized coal as the research object and controlled pulverized coal output by controlling different phase flows (liquid-solid two-phase, gas-liquid-solid three-phase). It carried out a pulverized coal start-transport test simulation of different particle sizes (less than 0.075 mm, 0.075～0.25 mm, 0.25～0.85 mm, over than 0.85 mm) in multi-phase flow conditions, and then analyzed the effects of flow rate, differential pressure, pipe inclination and grain size on coal start-transport. The results showed that under the liquid-solid two-phase flow, with the gradual increase of liquid flow, the pulverized coal gradually transitions from static state to sliding state to intermittent rolling state to rolling state to layer moving state to layer moving and suspending state and then to suspending state. The smaller the particle size of pulverized coal was, the lower the inclination angle of pipeline would be and the lower the starting flow rate would be; the flow rate showed a good linear relationship with the pressure difference, and they were both affected by the inclination of the pipeline.The particle size of pulverized coal and the inclination of the pipeline hadan important influence on the difficulty of starting-transporting of the pulverized coal, but the influence of both was complicated. The start-transport flow of different particle sizes of pulverized coal is not a simple linear relationship with the inclination of the pipe. The relationship between the particle size of pulverized coal particles (except for large-sized pulverized coal larger than 0.85 mm) and the starting flow rate can be characterized by a linear relationship at different angles, and the equation can also be used to predict the starting flow rate of coal powder with different particle sizes under specific pipe inclination angle.Under the gas-liquid-solid three-phase flow, the main controlling factor of pulverized coal start-transport was flow pattern, which was affected by gas-liquid flow ratio and pipe inclination, it which mainly included bubble flow, plug flow, stratified flow, wavy flow and slug flow. The transport capacity of each flow pattern is gas flooding laminar flow > slug flow > plug flow > bubble flow > stratified flow.With the increase of gas-liquid ratio, the pressure difference decreased rapidly first and then tended to be flat, and eventually rebounded slightly. The smaller the inclination angle of pipeline was, the faster the pressure difference decreased.