To determine reasonable distance of gas pre-drainage drillings in coal seams, a solid–gas coupling model that takes gas adsorption effect into account was constructed. In view of different adsorption constants,the pa...To determine reasonable distance of gas pre-drainage drillings in coal seams, a solid–gas coupling model that takes gas adsorption effect into account was constructed. In view of different adsorption constants,the paper conducted the numerical simulation of pre-drainage gas in drillings along coal seam, studied the relationship of adsorption constants and permeability, gas pressure, and effective drainage radius of coal seams, and applied the approach to the layout of pre-drainage gas drillings in coal seams. The results show that the permeability of coal seams is on the gradual increase with time, which is divided into three sections according to the increase rate: the drainage time 0–30 d is the sharp increase section;30–220 d is the gradual increase section; and the time above 200 d is the stable section. The permeability of coal seams is in negative linear and positive exponent relation with volume adsorption constant VLand pressure adsorption constant PL, respectively. The effective drainage radius is in negative linear relation with VLand in positive exponent relation with PL. Compared with the former design scheme, the engineering quantity of drilling could be reduced by 25%.展开更多
呼吉尔特矿区属于鄂尔多斯盆地侏罗系煤田深埋区,可采煤层上覆较强富水性厚层砂岩含水层。随着煤层开采,顶板水进入矿井,严重影响矿井安全生产。矿区范围内,各生产矿井涌水量均较大,最大矿井涌水量达到2289 m 3/h,且仍呈上升趋势。针对...呼吉尔特矿区属于鄂尔多斯盆地侏罗系煤田深埋区,可采煤层上覆较强富水性厚层砂岩含水层。随着煤层开采,顶板水进入矿井,严重影响矿井安全生产。矿区范围内,各生产矿井涌水量均较大,最大矿井涌水量达到2289 m 3/h,且仍呈上升趋势。针对这一情况,以该矿区涌水量最大的某矿井为例,对该矿区矿井涌水量变化规律和影响因素,从开采煤层上覆含水层赋存特征、巷道掘进长度、采空区半径、含水层疏降等方面,做了分析研究。结果表明:该矿区煤层顶板导水裂缝带范围内,发育有2~3层砂岩含水层,富水性差异较大,不同程度地影响矿井涌水量。在建井阶段,矿井涌水量随着巷道进尺的增加而增大,而矿井单位进尺涌水量和巷道单位进尺涌水量呈减小趋势。采前对工作面上覆含水层静储量进行计算,采取超前预疏放措施,充分疏放含水层静储量,可达到安全回采条件。矿井生产建设过程中,矿井涌水量先期呈大幅度增大的趋势,随着矿井采空区面积的不断增大,疏放影响范围增大,矿井涌水量增长幅度趋缓。展开更多
基金Financial support for this work,provided by the National Natural Science Foundation of China(Nos.51327007,51104118 and51204134)Shaanxi Province Youth Science and Technology Star Project of China(2014KJXX69)
文摘To determine reasonable distance of gas pre-drainage drillings in coal seams, a solid–gas coupling model that takes gas adsorption effect into account was constructed. In view of different adsorption constants,the paper conducted the numerical simulation of pre-drainage gas in drillings along coal seam, studied the relationship of adsorption constants and permeability, gas pressure, and effective drainage radius of coal seams, and applied the approach to the layout of pre-drainage gas drillings in coal seams. The results show that the permeability of coal seams is on the gradual increase with time, which is divided into three sections according to the increase rate: the drainage time 0–30 d is the sharp increase section;30–220 d is the gradual increase section; and the time above 200 d is the stable section. The permeability of coal seams is in negative linear and positive exponent relation with volume adsorption constant VLand pressure adsorption constant PL, respectively. The effective drainage radius is in negative linear relation with VLand in positive exponent relation with PL. Compared with the former design scheme, the engineering quantity of drilling could be reduced by 25%.
基金Project supported by the National Natural Science Foundation of China(No.51508503)the Fund of the China Scholarship Council(No.201406320025)the Research Plan of the Academician Workstation of Guangzhou Chemical Grouting Co.Ltd.,China Academy of Science(No.2016GZZ01)
文摘呼吉尔特矿区属于鄂尔多斯盆地侏罗系煤田深埋区,可采煤层上覆较强富水性厚层砂岩含水层。随着煤层开采,顶板水进入矿井,严重影响矿井安全生产。矿区范围内,各生产矿井涌水量均较大,最大矿井涌水量达到2289 m 3/h,且仍呈上升趋势。针对这一情况,以该矿区涌水量最大的某矿井为例,对该矿区矿井涌水量变化规律和影响因素,从开采煤层上覆含水层赋存特征、巷道掘进长度、采空区半径、含水层疏降等方面,做了分析研究。结果表明:该矿区煤层顶板导水裂缝带范围内,发育有2~3层砂岩含水层,富水性差异较大,不同程度地影响矿井涌水量。在建井阶段,矿井涌水量随着巷道进尺的增加而增大,而矿井单位进尺涌水量和巷道单位进尺涌水量呈减小趋势。采前对工作面上覆含水层静储量进行计算,采取超前预疏放措施,充分疏放含水层静储量,可达到安全回采条件。矿井生产建设过程中,矿井涌水量先期呈大幅度增大的趋势,随着矿井采空区面积的不断增大,疏放影响范围增大,矿井涌水量增长幅度趋缓。
