Evaluation method of regional anti-outburst effect based on resistivity image

LIU Jianfeng; LI Zhe; LEI Wenjie; DONG Runping

doi:10.13347/j.cnki.mkaq.20250551

Abstract：Coal seam gas pressure is an important indicator for the evaluation of regional outburst prevention effect.Due to the influ-ence of coal seam fractures,it is difficult to accurately measure the residual gas pressure of coal seams.In order to improve the timeliness and reliability of the evaluation of regional outburst prevention effect,a comprehensive evaluation method based on the combination of blank zone drainage,borehole resistivity and residual gas pressure is proposed,and the critical index is determined.The on-site investigation was conducted on the anti-outburst effect of hydraulic hole-making and gas drainage in the borehole of the No.15 coal seam bottom pumping roadway in Xinjing Mine,Yangquan Coalfield.The drainage volume of the borehole,gas content,gas pressure and other gas parameters were regularly tested.The borehole trajectory,lateral resistivity,natural potential and natural gamma and other borehole logging data in the caving and drainage borehole were tested and recorded and stored irregularly.The changes in borehole logging and the gas pressure of the investigation borehole in the coal seam section of the hydraulic hole-making drainage borehole at different times,as well as the gas drainage effect are analyzed.Through data regression and fitting,it is found that there is a common logarithmic negative correlation between the lateral resistivity of the drainage borehole and the gas pressure of the investigated borehole.Thus,the mathematical model and corresponding coefficients for evaluating gas pressure by resistivity are obtained.When the average resistivity of the coal seam section in the drainage hole reaches 750 Ω·m,it is equivalent to the gas pressure of the exploration hole at 0.74 MPa.This is equivalent to the resistivity index value corresponding to the critical index of the gas pressure of the coal seam in the exploration hole;meanwhile,the construction deviation of the regional outburst prevention bore-holes and the spacing at the bottom of the boreholes are investigated by using the borehole trajectories to evaluate whether there are blank zones within the range of outburst prevention measures,and determine whether it is necessary to add or supplement regional outburst prevention boreholes by means of the influence radius of caving and drainage.By integrating the resistivity and the drilling trajectory,a continuous anti-outburst effect inspection method that integrates the evaluation of drilling construction effect and the in-vestigation of anti-outburst effect,is immediate and effective,and can be adapted to large areas and long distances is formed.