煤层气开采是一个降压排采过程，随着煤储层流体压力、有效应力的不断变化，孔裂隙系统开发动态效应集中体现于煤层渗透性变化，并在很大程度上影响煤层气井产能效果。煤储层含气性与储层物性综合影响着煤层气井的产气效果，并影响着后期煤层气井型选择与井位部署。 通过对彬长矿区大佛寺井田地质资料以及地面煤层气直井现场排采数据的收集，研究了大佛寺井田煤储层特性及储层参数的变化规律。利用研究区典型垂直井的试井资料及历史排采资料，在研究大佛寺煤储层孔裂隙及煤层气富集特征的基础上，进行了煤层气直井排采阶段划分及产能分析，并将排采曲线划分为五种类型。基于渗流力学和煤储层地质学，对泰斯公式的变流量公式进行了修改，建立了煤层气井产气量模型以及煤层气井降压排采过程中的储层参数变化模型，结合Excel自带的VBA开发工具，编程实现了计算，模型结果与实际拟合较好；在煤层气降压排采阶段，渗透率先急剧减小，再缓慢减小直至平稳；进入气水两相流阶段，渗透率平稳中逐渐增大，后急剧上升至最大，达到100mD左右。 大佛寺地区煤层具有较高渗透率，处于煤层气稳产阶段的直井，由于弹性自调节正、负效应作用，基本实现产气的自我调节，建议可将井口套压维持在一个稳定值来维持其产气量。后期随着产气量平稳增长，要防止套压下降过快，使气压的降落漏斗缓慢拓展，远端的地层水发生流动，实现稳产，以达到煤层气高效滚动开发的目的。

The production of coalbed methane(CBM)is a process of pressure reduction and drainage. With the constantly changing of the fluid pressure and effective stress of coal reservoir, the dynamic effect of pore fissure system is embodied in the change of permeability of coal seam, and the impact of coalbed methane well productivity effect to a great extent. The containing gas and reservoir comprehensive of coal storage layer influence of CBM gas production effect, and the effect of CBM type in the late selection and placement. After collecting CBM vertical wells production data and geologic data in Dafosi mine of Binchang mining area, the characteristics and variation of coal reservoir and its parameters were studied. using the testing and production data of typical vertical wells, based on the study of coal reservoir hole cracks and the characteristics of coalbed methane enrichment in the study area, the classification and productivity analysis of CBM vertical wells drainage was carried out, and the production curve was divided into five types. Based on fluid mechanics and coal reservoir geology, the Theis formula of variable flow formula was modified, change of reservoir parameter model and coal gas production model in the process of drainage and depressurization were established. All the production data analysis were achieved by programming in VBA which is Excel own development tool, the models results were in good agreement with the actual data. The conclusion of the paper is that: in the stage of drainage and depressurization, the permeability decrease sharply at first, then slowly decreases until smooth into the two-phase flow of gas and water, the permeability gradually increase at first, and then a sharp rise to the maximum which achieving about 100mD. Coal seam of Dafosi has a nature of high permeability. Due to the elastic self-adjusting positive and negative effects, the production of vertical wells which in the period of stable stage basically have the ability of self-adjusting. It is suggest that maintaining the surface casing pressure in a stable value for gas production staying in stable level. With the steady growth of gas production in the later period, should prevent casing pressure drop too fast, for slowly extending of pressure funnel, driving water in the distance start to flow, realizing stable yield, for leading the exploitation of CBM achieve a high efficiency sustainable pace in conclusion.