金沙县官田坝向斜瓦斯赋存规律差异性分析

Gas Hosting Pattern Variance Analysis in Guantianba Syncline,Jinsha County

为查明贵州金沙县官田坝向斜瓦斯赋存规律,保证后续煤矿开采工作的有序进行,基于研究区地质勘探钻孔资料、试井资料及井田地质条件的详细分析,结合实测瓦斯数据,借助于瓦斯地质理论,从垂向和平面两方面对不同煤层进行瓦斯赋存规律分析探讨,结果表明:在取样深度范围内,可采煤层CH4浓度分布变化较大,N2浓度分布变化较小。各层位煤层在埋深处于500600m普遍存在明显的"转折点",推测可能与地层层序格架控制的煤储层物性有关;随着煤层层位的加深,瓦斯含量与埋深的关系逐渐趋于弱化,一定程度上表明埋深因素对于瓦斯含量的控制作用随着煤层层位的加深而逐渐较弱;4、7、9号煤层瓦斯含量受埋深影响作用明显,13、15号煤层瓦斯赋存规律一定程度上受地下水活动作用控制。

To find out gas hosting pattern in the Guantianba syncline,Jinsha County,Guizhou Province,guarantee further coalmine exploitation in order,based on study area geological exploration drilling data,pilot well tested data and minefield geological condition detailed analysis,combined with measured gas data,by means of gas geology theory have carried out gas hosting pattern analysis and discussion on different coal seams from vertical and horizontal two sides.The results have shown that within sampling depth extent,the mineable coal seam CH4 concentration distribution has larger variation,while the variation of N2 smaller.Coal seams in each horizon have obvious ＂turning point＂ within buried depth 500600 m generally,inferred possibility related to the strata sequence framework controlled coal reservoir physical properties.Along with coal seam horizon deepening,relationship between gas content and buried depth gradually tends to weakening.It has shown that in a certain degree,the control from buried depth on gas content will gradually weaken along with coal seam horizon deepening.The gas content of coal seam Nos.4,7 and 9 have obviously impacted by buried depth;while gas hosting pattern of coal seam Nos.13 and 15 controlled by groundwater activities in a certain degree.