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
Aiming at the uncontrollable problem of extension direction of coal seam hydraulic fracturing,this study analyzed the course of fractures variation around the boreholes in process of hydraulic fracturing,and carried o...Aiming at the uncontrollable problem of extension direction of coal seam hydraulic fracturing,this study analyzed the course of fractures variation around the boreholes in process of hydraulic fracturing,and carried out the numerical simulations to investigate the effect of artificial predetermined fractures on stress distribution around fractured holes.The simulation results show that partial coal mass occurs relatively strong shear failure and forms weak surfaces,and then fractures extended along the desired direction while predetermined fractures changed stress distribution.Directional fracturing makes the fractures link up and the pressure on coal mass is relieved within fractured regions.Combining deep hole controlling blasting with hydraulic fracturing was proposed to realize the extension guiding-controlling technology of coal seam fractures.Industrial experiments prove that this technology can avoid local stress concentration and dramatically widen the pressure relief scope of deep hole controlling blasting.The permeability of fractured coal seam increased significantly,and gas extraction was greatly improved.Besides,regional pressure relief and permeability increase was achieved in this study.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
为了解决高压欠注水井降压增注中面临的难题,以定边油田低渗透油藏的主力区块为研究对象,研究该区块的高压注水井在线酸化增注技术。利用单步法酸液体系可以抑制二次、三次沉淀物和溶解堵塞物的特性,设计在线单步法酸化智能增注系统,通...为了解决高压欠注水井降压增注中面临的难题,以定边油田低渗透油藏的主力区块为研究对象,研究该区块的高压注水井在线酸化增注技术。利用单步法酸液体系可以抑制二次、三次沉淀物和溶解堵塞物的特性,设计在线单步法酸化智能增注系统,通过“监控表皮系数变化情况”判断“是否对目的层段持续酸化”,确保最佳酸化效果。室内实验和现场试验结果表明:G-智能复合酸对氟化钠和氟硅酸盐产生二次沉淀的抑制性最好,单步法酸液体系选择G-智能复合酸可以更好地抑制酸反应时二次沉淀物的产生;堵塞物在酸液+助渗透剂剂T影响下的溶蚀率在73.9%~79%之间,堵塞物溶蚀率高于仅加入酸液的,单步法酸液体系选择酸液+助渗透剂可提升堵塞物溶蚀率;与只注入助渗透剂T相比,注入G-智能复合酸+助渗透剂T的高压注水井的油压下降1.0~3.4 MPa,日注水量增加6.1~9.8 m 3,该技术优势显著。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supported by National Natural Science Foundation of China(Grant No.51274195)Natural Science Foundation of Jiangsu Province(Grant No.BK2012571)+2 种基金China Post-doctoral Science Foundation(Grant No.20090450930)National Basic Research Program of China(973 Project)(Grant No.2011CB201205)Youth Foundation of China University of Miningand Technology(Grant No.2007A003)
文摘Aiming at the uncontrollable problem of extension direction of coal seam hydraulic fracturing,this study analyzed the course of fractures variation around the boreholes in process of hydraulic fracturing,and carried out the numerical simulations to investigate the effect of artificial predetermined fractures on stress distribution around fractured holes.The simulation results show that partial coal mass occurs relatively strong shear failure and forms weak surfaces,and then fractures extended along the desired direction while predetermined fractures changed stress distribution.Directional fracturing makes the fractures link up and the pressure on coal mass is relieved within fractured regions.Combining deep hole controlling blasting with hydraulic fracturing was proposed to realize the extension guiding-controlling technology of coal seam fractures.Industrial experiments prove that this technology can avoid local stress concentration and dramatically widen the pressure relief scope of deep hole controlling blasting.The permeability of fractured coal seam increased significantly,and gas extraction was greatly improved.Besides,regional pressure relief and permeability increase was achieved in this study.
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.
文摘为了解决高压欠注水井降压增注中面临的难题,以定边油田低渗透油藏的主力区块为研究对象,研究该区块的高压注水井在线酸化增注技术。利用单步法酸液体系可以抑制二次、三次沉淀物和溶解堵塞物的特性,设计在线单步法酸化智能增注系统,通过“监控表皮系数变化情况”判断“是否对目的层段持续酸化”,确保最佳酸化效果。室内实验和现场试验结果表明:G-智能复合酸对氟化钠和氟硅酸盐产生二次沉淀的抑制性最好,单步法酸液体系选择G-智能复合酸可以更好地抑制酸反应时二次沉淀物的产生;堵塞物在酸液+助渗透剂剂T影响下的溶蚀率在73.9%~79%之间,堵塞物溶蚀率高于仅加入酸液的,单步法酸液体系选择酸液+助渗透剂可提升堵塞物溶蚀率;与只注入助渗透剂T相比,注入G-智能复合酸+助渗透剂T的高压注水井的油压下降1.0~3.4 MPa,日注水量增加6.1~9.8 m 3,该技术优势显著。
