Technologies of downward drilling construction in aquifers

摘要

This paper analyses the bad effect of gas extraction using downward drilling boreholes in Gubei Mine and presents a set of downward drilling construction technologies.Accurate designed parameters ensure effective construction.Grouting slurry to block crack of surrounding rock and sandstone can decrease water content in the bottom of boreholes and increase methane desorption.Casing pipe is used to prevent the borehole wall collapse and block the borehole.New sealing packer will seal borehole strictly.Solenoid valve can realize automatic drainage to improve gas extraction effect.All of these technologies are applied in the 5# drilling field construction at high-level suction roadway of the 4 coal seam.In engineer experiment, the 2-3# drilling field without using new technologies is chose as contrast experiment.According to comparing the gas extraction concentration and flow of the two drilling fields', the results show that the construction techniques can enhance the effect of gas extraction in aquifers.