煤储层渗透率变化新模型及控制因素研究  

A New Model for Variation of Coal Seam Permeability and Study on Influence Factors

作　　者：戚宇[1,2] 韦重韬[1,2] 邹明俊[1,2] 

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116 [2]中国矿业大学煤层气资源与成藏过程教育部重点实验室,江苏徐州221008

出　　处：《煤炭工程》2015年第2期99-101,共3页Coal Engineering

基　　金：国家科技重大专项(2011ZX05034)

摘　　要：根据储层压力下降和煤基质收缩效应建立了渗透率变化数学模型,模型应用及参数敏感性分析结果表明:排采过程中,渗透率先减小后增加,并根据水平有效应力变化值将排采过程分为三个阶段;泊松比越大,水平有效应力变化值越趋向于增加,渗透率越趋向于衰减;极限吸附量和吸附常数越大,水平有效应力变化值越趋向于减小,渗透率越趋向于增加;实际排采时,在井底流压降至渗透率反弹点压力之前,要尽量减小排采强度,防止近井处渗透率快速下降阻碍排水降压,在降至渗透率反弹点压力之后,适当增大排采强度,使渗透率尽快反弹。Based on reservoir pressure drop and coal matrix shrinkage effect, a mathematic model was built for permeability variation. According to the application and sensitivity analysis of the model, it is concluded that, in CBM drainage, coal permeability increases firstly and then decreases, this process can be divided into three stages based on different value of effective horizontal stress change; when the Poisson＇s ratio increases, the effective horizontal stress intends to increase, when Langmuir volume and Langmuir constant increase, the effective horizontal stress tends to decrease ; in CBM production, small drainage rate is recommended when reservoir pressure is larger than the pressure at permeability rebounding point and drainage rate shall be appropriately larger after reservoir pressure drops to the pressure at permeability rebounding point.

关 键 词：煤储层渗透率 煤层气井 排采 储层压力 煤基质收缩 

分 类 号：TD712.1[矿业工程—矿井通风与安全]