Desorptivity of coalbed methane (CBM) is one of the key controls to CBM recovery ratio and production. Based on the canister desorption experiments and relevant data of the 62 coal core samples from the Hancheng block, the correlation of the desorptivity to the geological controls such as the coal rank, coal quality and maceral composition is discussed. Results showed that the desorption ratios of all samples are higher than 80%, commonly from 90% to 95%- Adsorption time ranges from 0,03d to 10d, in which the desorption ratios of the 82% samples are less than 6d- CBM desorbed with the stages, the reduction of the desorption rate was resulted from the change of the average CBM content. Initial desorption rate and its attenuation are related to the pore texture and connectivity in the samples. Desorption ratio has not a clear correlation with the coal rank but reduces obviously with the increase of ash yield* Moreover, desorption ratio increases with increasing the vitrinite content and reduces with decreasing the inertinite content. Adsorption time shortens discretely with the increase of the fixed carbon or moisture contents, but has not a obvious correlation with the ash yield and maceral content.School of Energy Resources, China University of Geosciences, Beijing 100083, China%煤层气解吸特征是影响煤层气采收率及排采效果的关键要素之一.基于对韩城煤层气示范区62件煤芯的解吸实验和相关测试,分析了煤层气解吸特征及规律,探讨了解吸特征与煤级、煤质、煤岩显微组成等的相互关系.结果表明,研究区煤层气解吸率多在90％～95％之间；吸附时间为0.03～10 d,82％的煤样小于6d.煤芯气体解吸具有阶段性,气体解吸速率的降低主要由煤芯平均含气量的变化引起,初始解吸速率及其衰减特征与煤岩孔隙结构及其连通性有关.解吸率与煤级相关性不明显,但随灰分产率增加而显著降低.镜质组含量的增加提高了煤层气解吸率,惰质组则相反.吸附时间随同定碳含量、水分含量的增加而缩短,但有一定离散性,与灰分产率、显微组分含量之间关系则不明显.
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