滇东黔西地区与沁水盆地煤储层地质特征对比分析

Coal Reservoir Geological Features Comparative Analysis between Eastern Yunnan,Western Guizhou Area and Qinshui Basin

为找出影响滇东黔西地区煤层气勘探开发相对滞后的主控地质因素,将滇东黔西地区与沁水盆地煤储层地质特征进行对比分析。研究结果表明,滇东黔西地区煤储层压力、含气饱和、临储比和含气量与沁水盆地差别不大,有利于煤层气的勘探开发。相同埋深条件下,滇东黔西地区煤储层地应力明显高于沁水盆地,渗透率则远低于沁水盆地。统计显示,沁水盆地煤储层渗透率大多在1mD左右,滇东黔西则基本低于0.1mD,大部分为0.01mD左右,至少低一个数量级以上。滇东黔西地区高地应力、低渗透率和构造煤发育可能是影响滇东黔西煤层气“可见难取”及其勘探开发相对滞后的最直接地质原因,复杂的构造演化则可能是其最根本原因。综合区域构造格局、构造曲率和矿井煤层剖面煤体结构观测是一种较好预测高应力区构造应力强弱区域分布的方法,可有效指导滇东黔西地区的煤层气勘探开发。

To find out the main control geological factors impacting relatively lagging behind CBM exploration and exploitation in the eastern Yunnan and western Guizhou area have carried out comparative analysis for coal reservoir geological features in the area and in the Qinshui Basin.The results have shown that the coal reservoir pressure,gas saturation,critical ratio of desorption pressure to reservoir pressure and gas content have not large difference,thus favorable to CBM exploration and exploitation.Under same buried depth,coal reservoir ground stress of the area is obviously higher than Qinshui Basin,while permeability far below.The statistics have shown that coal reservoir permeability in Qinshui Basin mostly about 1mD,while in the area basically lower than 0.1mD,mostly about 0.01mD,at least lower an order of magnitude.High ground stress,low permeability and developed tectonoclastic coal are the most direct geological factors impacting the area’s CBM“visible but hard to acquire”thus exploration and exploitation relatively lagging behind;while the complex structural evolution possibly the essential causation.The integrated regional tectonic framework,structural curvature and mine coal section coal mass structural observation is a better method to predict high stress area tectonic stresses regional distribution,to guide CBM exploration and exploitation in the area effectively.