To improve the gas extraction efficiency of single seam with high gas and low air permeability,we developed the"fracturing-sealing"integration technology,and carried out the engineering experiment in the3305...To improve the gas extraction efficiency of single seam with high gas and low air permeability,we developed the"fracturing-sealing"integration technology,and carried out the engineering experiment in the3305 Tunliu mine.In the experiment,coal seams can achieve the aim of antireflection effect through the following process:First,project main cracks with the high energy pulse jet.Second,break the coal body by delaying the propellant blasting.Next,destroy the dense structure of the hard coal body,and form loose slit rings around the holes.Finally,seal the boreholes with the"strong-weak-strong"pressurized sealing technology.The results are as follows:The average concentration of gas extraction increases from8.3%to 39.5%.The average discharge of gas extraction increases from 0.02 to 0.10 m^3/min.The tunneling speeds up from 49.5 to 130 m/month.And the permeability of coal seams improves nearly tenfold.Under the same conditions,the technology is much more efficient in depressurization and antireflection than common methods.In other words,it will provide a more effective way for the gas extraction of single seam with high gas and low air permeability.展开更多
Hydraulic slotting can induce drill spray in a gassy,low permeability coal seam.This then influences subsequent gas extraction.This paper describes the drill spray phenomenon from a mechanical perspective and analyzes...Hydraulic slotting can induce drill spray in a gassy,low permeability coal seam.This then influences subsequent gas extraction.This 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 code.It helps explain the induction of drill spray during hydraulic slotting.The stress concentration around the bore increases as the diameter of the hole increases.As the hole enlarges the variation in stress also increases,which introduces an instability into the coal.This allows easy breaking and removal of the coal.Destruction of the coal structure by the water jet is the major factor causing drill spray.Energy 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 hole.Field tests showed the effect on gas extraction after slotting with drill spray.The concentration of gas increases after drilling.Compared to conventional techniques,the hydraulic slotted bore gives a gas concentration three times higher and has an effective range twice as far.This makes the gas extraction process more efficient and allows reduced construction effort.展开更多
针对中近距离松软低透气性突出煤层群抽采防突难题,以皖北矿区任楼煤矿突出煤层群瓦斯地质条件为工程背景,在对松软煤层水力割缝卸压增透机制、首采层割缝工艺参数等研究的基础上,提出了首采层煤巷条带水力割缝卸压增透、煤层群瓦斯联...针对中近距离松软低透气性突出煤层群抽采防突难题,以皖北矿区任楼煤矿突出煤层群瓦斯地质条件为工程背景,在对松软煤层水力割缝卸压增透机制、首采层割缝工艺参数等研究的基础上,提出了首采层煤巷条带水力割缝卸压增透、煤层群瓦斯联合抽采的综合治理技术,优化了钻孔布置方式,并进行了工程应用。结果表明:割缝实施后钻孔的瓦斯抽采浓度、单孔日均抽采纯量分别是常规钻孔的4.27倍、3.94倍,煤层透气性提高了22~31倍,首采层72号煤层割缝后的防突有效半径可提高至5 m以上,检验抽采半径5 m处的瓦斯含量指标为4.13 m 3/t,在有效解决首采层煤巷条带瓦斯灾害的同时,钻孔工程量降低了2/3以上。展开更多
基金financial 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)
文摘To improve the gas extraction efficiency of single seam with high gas and low air permeability,we developed the"fracturing-sealing"integration technology,and carried out the engineering experiment in the3305 Tunliu mine.In the experiment,coal seams can achieve the aim of antireflection effect through the following process:First,project main cracks with the high energy pulse jet.Second,break the coal body by delaying the propellant blasting.Next,destroy the dense structure of the hard coal body,and form loose slit rings around the holes.Finally,seal the boreholes with the"strong-weak-strong"pressurized sealing technology.The results are as follows:The average concentration of gas extraction increases from8.3%to 39.5%.The average discharge of gas extraction increases from 0.02 to 0.10 m^3/min.The tunneling speeds up from 49.5 to 130 m/month.And the permeability of coal seams improves nearly tenfold.Under the same conditions,the technology is much more efficient in depressurization and antireflection than common methods.In other words,it will provide a more effective way for the gas extraction of single seam with high gas and low air permeability.
基金support provided by the State Key Basic Research Program of China(No.2011CB201205)the National Natural Science Foundation of China(No.51074161)+3 种基金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
文摘Hydraulic slotting can induce drill spray in a gassy,low permeability coal seam.This then influences subsequent gas extraction.This 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 code.It helps explain the induction of drill spray during hydraulic slotting.The stress concentration around the bore increases as the diameter of the hole increases.As the hole enlarges the variation in stress also increases,which introduces an instability into the coal.This allows easy breaking and removal of the coal.Destruction of the coal structure by the water jet is the major factor causing drill spray.Energy 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 hole.Field tests showed the effect on gas extraction after slotting with drill spray.The concentration of gas increases after drilling.Compared to conventional techniques,the hydraulic slotted bore gives a gas concentration three times higher and has an effective range twice as far.This makes the gas extraction process more efficient and allows reduced construction effort.
文摘针对中近距离松软低透气性突出煤层群抽采防突难题,以皖北矿区任楼煤矿突出煤层群瓦斯地质条件为工程背景,在对松软煤层水力割缝卸压增透机制、首采层割缝工艺参数等研究的基础上,提出了首采层煤巷条带水力割缝卸压增透、煤层群瓦斯联合抽采的综合治理技术,优化了钻孔布置方式,并进行了工程应用。结果表明:割缝实施后钻孔的瓦斯抽采浓度、单孔日均抽采纯量分别是常规钻孔的4.27倍、3.94倍,煤层透气性提高了22~31倍,首采层72号煤层割缝后的防突有效半径可提高至5 m以上,检验抽采半径5 m处的瓦斯含量指标为4.13 m 3/t,在有效解决首采层煤巷条带瓦斯灾害的同时,钻孔工程量降低了2/3以上。
