钻孔剖面多煤层物性X-CT响应及其地质意义

X-CT Response and Physical Properties of Multiple Coal Seams on Drilling Columnar Section its Geological Implication

基于钻孔剖面不同煤层的X-CT物性响应,分析了煤层物性及其在垂向序列上的非均质性特征。发现研究区3号、14号、23号、26号煤层的孔隙-裂隙较为发育,煤中孔隙呈星散状产出,裂隙不甚发育,且多被矿物充填。通过CT切片"顺层偏差"来定量表征煤层的非均质性,发现研究区含煤地层4个三级层序主煤层的CT偏差在垂向上呈单峰分布,以层序Ⅲ最大,指示其非均质性最强,同时也说明CT方法可用以定量表征煤层的非均质性特征。发现煤样CT偏差的垂向分布与海水进退旋回具有高度的一致性,说明在海水进退控制下的成煤环境是影响煤层非均质性的关键因素。

Based on physical properties of X-CT on different coal seams in histogram section of borehole, physical properties of coal seams and its heterogeneity on vertical sequence were analyzed. The research found that the pores diffusely distributed in coal of No. 3, 14, 23 and 26 coal seams are well developed in study area, and the fractures are not well-developed and mostly filled by minerals. The CT number deviation was introduced to quantify the heterogeneity of coal. The results showed that the deviation of main coal seams from four sequences of study showed a single peak distribution in the vertical direction, and the deviation of sequence Ⅲ was that the biggest, which implied that the heterogeneity of sequence Ⅲ was the strongest, which also showed the heterogeneity of coal reservoir can be quantitative by the CT method. The research found that there has a high degree of consistency between vertical distribution of CT number deviation and cycle of the sea, which indicated that the coal-forming environment is the key factor of influencing the heterogeneity of coal seam under the control of the marine transgression and regression.