Key technology for rapidly drilling large-diameter destressing drillhole in rockburst coal seam
(2.Xi’an Research Institute Co., Ltd., China Coal Technology and Engineering Group Corp., Shaanxi Xi’an 710077)
【Abstract】In order to improve the hole forming rate and construction efficiency of large-diameter destressing drillhole in rockburst mine, based on the analysis of the stress characteristics of coal rock in a rockburst coal mine, the dynamic instability characteristics of destressing drillhole, and the construction features, this paper proposed the key points for drilling large-diameter destressing drillhole, the efficient discharge of cuttings and fast drilling/lifting. Combined with the discharge of cuttings method by dual-power, this paper formed the technology and equipment for rapidly drilling large-diameter destressing drillhole in rockburst coal seam finally after the design and optimization of key equipment, drilling tools, technology and drilling processes. With the equipment based on the ZDY4000LR rig and the technology including water medium and spiral wide-wing drilling pipe, the drillholes were drilled safely and efficiently. And the method was proved and used at the Henan Yima and Shaanxi Binchang coalfields. The tests show that the large-diameter destressing drillhole could be constructed efficiently and safely, and the efficiency is increased by 48.9% compared with high- and thin-helical-blade drilling-pipe drilling method. The hole forming rate reached 100%, and the method has high application value and popularization significance. And this method can be used for reference in drilling destressing drillhole in similar coal mines.
【Keywords】 rockburst; destressing drillhole; ZDY4000LR rig; discharge of cuttings method by mix-power; Henan Yima coalfield; Shaanxi Binchang coalfield;
(Translated by WU J)
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