井下煤层瓦斯压力与含量直接测定技术研究进展

Research progress of direct measurement of gas pressure and content in underground coal seams

井下煤层瓦斯压力与含量的快速准确测定是进行煤矿灾害瓦斯预测及防治的基础。根据封孔材料的不同,将井下煤层瓦斯压力直接测定分为固体封孔法和液体封孔法两大类,分析了各自的优缺点与适用性,指出固液耦合定点定位动态智能封孔、连续实时可视化监测煤层瓦斯压力是发展方向。按取样方式将井下煤层瓦斯含量直接测定分为钻屑法和取芯法两大类,指出负压排渣和正压逆流定点取样具有煤样纯度高、操作简便、取样时间短等优点,取样系统结构优化和类似环境下瓦斯损失量计算模型研究是重点;密闭和冷冻取样可以最大限度避免煤样瓦斯损失,取样器结构简化、取样过程瓦斯损失补偿计算精细化、随钻快速“保真”取样和钻孔内原位测定技术是井下煤层瓦斯含量测定的发展趋势。

The rapid and accurate determination of gas pressure and content in underground coal seams is the basis for gas prediction and prevention of coal mine disasters.According to the different sealing materials,the direct determination of gas pressure in underground coal seams is classified into two categories:solid sealing method and liquid sealing method,and their respective advantages and disadvantages and applicability are analysed,and it is pointed out that the solid-liquid coupling fixed-point and positioning dynamic intelligent sealing,and continuous realtime visual monitoring of coal seam gas pressure are the direction of development.According to the sampling method,the direct determination of gas content in underground coal seams is divided into two categories:drilling cutting method and coring method.It is pointed out that negative-pressure slag discharge and positive-pressure countercurrent fixed-point sampling have the advantages of high purity of coal samples,easy operation and short sampling time,etc.The optimisation of the structure of the sampling system and the research on the model for calculating the amount of gas loss in similar environments are the key points.Confined and frozen sampling can avoid the loss of gas in coal samples to the greatest extent possible.Simplified of sampler structure,refined calculation of gas loss compensation in sampling process,rapid"fidelity"sampling while drilling,and in-situ measurement in the borehole are the development trends of gas content determination in underground coal seams.