Advanced fine detection technology of coal and gas outburst danger area

Abstract

According to the geological structure and environmental characteristics of coal and gas outburst and the shortcomings of existing outburst prediction index system, the borehole radar is used to carry out the advanced and fine detection of gas geological abnormal body with the help of the regional prediction boreholes constructed in the heading face, which is to achieve efficient and accurate prediction of coal and gas outburst. According to the time-domain profile of the reflected signal detected by single borehole of borehole radar, the distortion shape and missing position of the in-phase axis of reflected signal and the two-way travel time of the echo signal are analyzed, and the key parameters such as the type, scale and distance of the gas geological abnormal body around the borehole can be revealed, which is to realize the fine detection of the coal and gas outburst danger area. The engineering test shows that: in the fracture development area, the reflection signal of borehole radar is strong; the more developed the fracture is, the stronger the reflection signal is; in the complete porous medium coal body, there is weak and stable reflection signal, while in the complete dense and homogeneous rock body, the reflection signal is very weak, almost no signal; in addition, the field application of the advanced fine detection technology in Shoushan No.1 mine accurately revealed the significant difference in the medium distribution in front of heading face. Combined with the rapid inversion technology of coal seam gas parameters while drilling, they realize the accurate identification of coal and gas outburst danger areas