古交区块8号煤层构造煤分布及成因分析

Distributional characteristics and its geneses analysis of tectonic coals in No. 8 coal seam of Gujiao Block

基于山西古交区块主采煤层地质背景,选取太原西山古交区块5口钻井作为测井识别煤体结构的刻度井,集成自然伽马、密度、电阻率、声波时差测井响应,识别了区内31口钻井煤体结构。计算各钻井碎粒煤~糜棱煤所占厚度比值,采用matlab软件计算和分析了影响碎粒煤~糜棱煤层域分布因素的总灰色关联度。结果表明,影响其层域分布的因素依次为夹矸厚度、煤层厚度、夹矸层数、煤层倾角等。此外对碎粒煤~糜棱煤区域分布控制因素进行了探讨,认为向斜翼部受透入性顺层剪切应力作用影响,碎粒煤~糜棱煤普遍发育,NE向正断层尖灭端控制了碎粒煤~糜棱煤局域分布。这些煤体结构层域和区域控制因素存在内在联系,并非相互孤立。

Five boreholes were selected in the Gujiao Block, Xishan, Taiyuan as calibration wells to identify the coal structure, according to the geological setting of major mineable coal seams in the block, and the coal structures of 31 boreholes were identified due to the results of integrated natural gamma, density, resistivity, and acoustic log responses. The thickness proportion of the fragmented to mylonitic coals （ Ⅲ- Ⅳ coals）for each borehole were calculated, and the degree of total grey correlation for the （ Ⅲ- Ⅳ coals ）, to which the layer distributing factors were influenced, was calculated and analyzed by Matlab software. Results indicate that the layer distributing factors mainly include the thickness and the dip of coal seams, and the thickness and number of intra - seam partings. In addition, the distribution controlling factors were further discussed, and results indicate that the III - IV coals are significantly developed in the syncline wings that are influenced by penetrative bedding shear stress, and have a local distribution controlled by the pinching - out of NE oriented normal faults. The layer distribution and regional controlling factor of coal structures are internally related rather than isolated to each other.