煤储层渗透率气体压力敏感性的影响因素探讨  

Influencing Factors Discussion on Gas Pressure Sensibility of Coal Reservoir Stratum Permeability

作　　者：曹偈[1,2] 戴林超[1,2] 王波[1,2] 

机构地区：[1]瓦斯灾害监控与应急技术国家重点实验室,重庆400037 [2]中煤科工集团重庆研究院有限公司,重庆400037

出　　处：《煤矿安全》2016年第8期182-185,189,共5页Safety in Coal Mines

基　　金：国家自然科学基金面上资助项目(51574280);"两江学者"计划专项经费资助项目([2013]渝九证字第1406号);中煤科工集团重庆研究院有限公司资助项目(2015DXM14);煤炭科学研究总院科技创新基金资助项目(2015ZYJ002)

摘　　要：为了探讨在煤层气排采过程中煤储层渗透率的动态演化规律,以松藻煤矿K2煤层煤样制作的型煤试件为研究对象,进行了不同应力、温度作用下煤渗透率随气体压力降低演化规律的试验研究。研究结果表明:煤的渗透率随气体压力下降基本呈现先减小后增大的趋势,渗透率最小值对应的气体压力临界值将渗透率随气体压力的演化分为2个阶段;根据气体压力敏感系数Cp定义,不同围压温度条件下气体压力敏感系数与气体压力呈现对数关系;由于有效应力与基质收缩效应2方面的影响,在初始阶段随围压及温度的升高煤渗透率对气体压力的响应程度增大,基于气体压力敏感系数建立了气体压力与渗透率的关系式,可为合理制定煤层气排采方案提供指导。To explore the dynamic evaluation laws of coal reservoir stratum permeability in the process of gas drainage and extraction,the experimental study on evolution laws that coal permeability decreases with gas pressure is carried out,which is made from K2 coal seam in Songzao Mine under different stress and temperature.The results show that the permeability of coal has a tendency that declining first and then rising again during the gas pressure unloading.And the gas pressure corresponding to the minimum permeability is the critical value of gas pressure,which divided the curve of coal permeability into two stages：initial stage and second stage.We define the variation of coal permeability which is caused by reducing unit gas pressure as the sensitive coefficient of gas pressure Cp,the relationship between Cpand gas pressure can be fitted by logarithmic function.Due to two aspects of effect including effective stress and matrix shrinkage effect,the response degree of permeability to gas pressure at initial stage and the critical gas pressure both show an increase trend with the increase of confining pressure or temperature.Then based on the Cp,the functional relationship between permeability of coal and gas pressure is derived,which can provide a basis for the reasonable gas drainage scheme.

关 键 词：渗透率 气体压力 敏感性系数 围压 温度 

分 类 号：TD712[矿业工程—矿井通风与安全]