为了探究水分含量和负压对煤层气等温吸附、解吸特征的影响，采用大样量煤层气吸附/解吸仿真试验设备对鄂尔多斯盆地东缘北部煤矿煤样进行煤层气常规等温吸附解吸过程和负压解吸过程的实验室模拟，通过将煤样进行处理得到干燥煤样、平衡水煤样、饱和水煤样3种不同含水饱和度煤样，分别对其进行等温吸附测试、常规等温解吸测试和负压解吸测试，得到了煤样在不同含水饱和度、不同负压条件下的压力与吸附量实测数据，并采用不同的吸附/解吸方程式进行拟合。通过对比分析，研究了水分对等温吸附过程、解吸过程以及负压对解吸过程的影响，并从分子间作用力的角度进行了解释水分对等温吸附解吸过程的影响。结果表明：煤样解吸过程与吸附过程不可逆，存在解吸滞后；由于水分子与煤分子间的作用力大于甲烷分子与煤分子间的作用力，水分在与甲烷的竞争吸附中具有优势，煤样含水率越高，其吸附甲烷的能力越低；煤样含水率较低时，含水对煤岩降压解吸影响不明显；当煤样含水率高于某一值时，外来水分抑制煤层气降压解吸，分析认为这可能与煤样的物质组成和煤分子结构有关；由于水分对甲烷的置换解吸作用，若水力压裂过程中压裂液滤失严重，将降低煤层吸附气量，延长排水降压阶段，减少累计产气量，因此应严格控制压裂液滤失；负压解吸阶段，单位压降引起的解吸量更大，说明负压排采增产措施具有潜力。

This paper presents results of an experimental study on the influence of water saturation and negative pressure on isothermal adsorption and desorption of coalbed methane.The conventional isothermal adsorption and desorption processes and isothermal desorption process under negative pressure were simulated using large quantity coalbed methane adsorption/desorption simulation equipment.The coal samples used in the simulation were collected from the northeastern Ordos Basin.Using different treatment technique, three coal samples which have different water saturation were obtained, namely dry coal sample, balanced water coal sample, and saturated water coal sample.The pressure and adsorption volume under different water saturation and different negative pressure were measured and then studied by regression analysis.The influence of water on isothermal adsorption process was analyzed and interpreted from the perspective of intermolecular forces.The results show that the desorption process and adsorption process of coal sample are irreversible, with desorption hysteresis.Water has advantage in competitive adsorption of water and methane because the interaction between water molecules and coal molecules is greater than that between methane molecules and coal molecules.It is also found that higher water saturation of coal sample is associated with lower methane adsorbing ability.Within a certain range, the effect of water on depressurized desorption process is not significant.However, above a certain level of water saturation, the external water inhibits the depressurized desorption process.The inhabitation might be related to compositions of coal samples and molecular structure of coal.When fracture fluid loss is severe, gas content of the coal seam decreases due to desorption of methane replaced by water, resulting in longer drainage time and reduced cumulative gas production.The result demonstrates that the fracture fluid loss should be controlled strictly.Desorption volume caused by the unit pressure drop is larger in negative pressure desorption stage, which indicates that the negative pressure drainage and production measures has potential to enhance CBM recovery.