沁水盆地安泽区块3号煤层煤体结构及其控气作用

Coal structure and gas controlling effect of seam No.3 in Anze block of Qinshui basin

  • 摘要: 沁水盆地安泽区块煤层形成后经历多期构造运动,致使煤体结构遭受不同程度的破坏,煤体结构的分布规律制约本区煤层气的开发。基于此,利用该区的测井资料,提出测井判识煤体结构的方法,将研究区单井3号煤层结构分为Ⅰ、Ⅱ、Ⅲ三种煤体结构类型组合,对比分析3号煤层不同煤体结构煤空间展布与煤层含气量、煤层埋深的相关性。结果表明:安泽地区碎裂-碎粒煤较原生结构煤、糜棱煤发育,南部碎裂-碎粒煤发育较厚,北部以糜棱煤发育相对较薄;煤层含气量随埋深有明显增加的趋势,但在同等埋深条件下,煤层含气量受不同煤体结构展布的影响较大,南部碎裂-碎粒煤发育较厚煤层吸附量大,出现煤层含气量的高值区。

     

    Abstract: Anze block of Qinshui basin has experienced several tectonic events since coal-forming period, resulting in the destruction of coal structure at different degrees, the exploitation of coal bed methane(CBM) in Anze block of QinShui basin has been restricted by the undefined distribution of the coal structure. Based on the above-mentioned fact, coal-bed structure of 3# seam in single well is classified into three coal structure types, namelyⅠ,Ⅱand Ⅲ, and the correlations among the spatial distributions, CBM content and burial depth of coal seams of different coal structures are analyzed comparatively by using logging data in the area and putting forward the method to recognize coal structures by logging data. The results showed that the cataclastic-ranulitic structural coal are more universal than undeformed coal and mylonitic structural coal in Anze block.In the south the cataclastic-granulitic structural coal is thick and in the north the mylonitic structural coal is thin. The CBM content increases significantly with the burial depth and is greatly influenced by the distribution of the coal structure at certain buried depth. The high content of CBM is present in the south because of a larger adsorptive capacity in the thick cataclastic-granulitic structural coal in this area.

     

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