Induced drill-spray during hydraulic slotting of a coal seam and its influence on gas extraction

作     者：Shen Chunming Lin Baiquan Zhang Qizhi Yang Wei Zhang Lianjun 

作者机构：School of Safety EngineeringChina University of Mining & Technology Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal MinesHunan University of Science and Technology 

出 版 物：《International Journal of Mining Science and Technology》 (矿业科学技术学报（英文版）)

年 卷 期：2012年第22卷第6期

页      面：785-791页

核心收录：

学科分类：081901[工学-采矿工程] 0709[理学-地质学] 0819[工学-矿业工程] 0808[工学-电气工程] 08[工学] 0818[工学-地质资源与地质工程] 0708[理学-地球物理学] 0807[工学-动力工程及工程热物理] 0815[工学-水利工程] 0813[工学-建筑学] 0814[工学-土木工程] 

基　　金：support provided by the State Key Basic Research Program of China(No.2011CB201205) the National Natural Science Foundation of China(No.51074161) the National Science and Technology Support Program(No.2012BAK04B07) the project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(No.CXZZ12_0958) the Open Foundation project of Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines(201201) support for the field application and tests of the technology 

主　　题：Slotted Drill-spray Water jet Pressure relief and permeability increase Gas extraction 

摘      要：Hydraulic slotting can induce drill spray in a gassy,low permeability coal *** then influences subsequent gas *** paper describes the drill spray phenomenon from a mechanical perspective and analyzes the effects of water jet damage during slotting.A simulation of the stresses around the drill hole and slot was prepared using FLAC-3D *** helps explain the induction of drill spray during hydraulic *** stress concentration around the bore increases as the diameter of the hole *** the hole enlarges the variation in stress also increases,which introduces an instability into the *** allows easy breaking and removal of the *** of the coal structure by the water jet is the major factor causing drill *** stored as either strain or gas pressure is released by the water jet and this causes the coal to fracture and be expelled from the *** tests showed the effect on gas extraction after slotting with drill *** concentration of gas increases after *** to conventional techniques,the hydraulic slotted bore gives a gas concentration three times higher and has an effective range twice as *** makes the gas extraction process more efficient and allows reduced construction effort.