Evaluation of coal structure by logging and its application in optimization of perforation section of coal reservoir in Weibei block

Coal seam of Weibei block is damaged seriously by multi period tectonic movement and the coal structure is very complicated. Based on core samples and well logging data, this paper analyzed response characteristics of different coal structure and presented logging identification chart of different coal structure of No.5 coal seam in fault zone and non-fault zone. The results show that coal structure of No.5 coal seam tends to be complete from bottom to top. In plane view, the structure of coal in northern area is mainly fractured coal and coal particles. Coal structure of southern area is relatively complete and local is structure coal. According to fracturing and drainage data, and the development of No.5 coal seam roof, this paper makes studies on daily gas production of different roof perforation ratio. When the roof is sandstone or muddy sandstone, gas production of tectonic coal is higher than that of mudstone or sandy mudstone roof. The more crushing the coal structure, the higher the perforation ratio. If the roof of coal is sandstone or muddy sandstone, roof perforated ratio can be higher.