非对称荷载下煤层瓦斯渗流特性与抽采半径优化  

Characteristics of coalbed gas seepage under asymmetric loading and optimization of extraction radius

作　　者：闫路 王涛 王连聪 李文璞 赵天维 YAN Lu;WANG Tao;WANG Liancong;LI Wenpu;ZHAO Tianwei(School of Safety and Emergency Management Engineering,Taiyuan University of Technology,Taiyuan Shanxi 030600,China;State Key Laboratory of Coal Mine Safety Technology,Fushun Liaoning 113122,China)

机构地区：[1]太原理工大学安全与应急管理工程学院,山西太原030600 [2]煤矿安全技术国家重点实验室,辽宁抚顺113122

出　　处：《中国安全科学学报》2024年第12期149-158,共10页China Safety Science Journal

基　　金：国家自然科学基金资助(52204105,51774182);山西省基础研究计划项目(202203021212229);中国博士后科学基金第75批面上项目资助(2024M751279)。

摘　　要：为了揭示非对称荷载对瓦斯渗流和抽采半径的影响特征,建立多物理场煤与瓦斯流固耦合模型,以研究煤层瓦斯渗流特性。该模型以基质吸附态瓦斯为质量源,将非对称荷载引入边界条件;同时,在非对称荷载环境下实施分段布孔,优化瓦斯抽采半径,提高抽采效率。结果表明:较大的应力压缩了集中应力区内部的裂隙,导致瓦斯更难流动,其内部的瓦斯更难被抽采。集中应力区的瓦斯压力下降幅度比原始应力区瓦斯压力下降幅度低2%左右,渗透率下降幅度低9%;同时非对称荷载下对扩散过程及渗流过程均产生不同程度的影响,在180天内,原始应力区扩散质量下降19%,渗流质量下降20.5%;集中应力区扩散质量下降16.9%,渗流质量下降17.9%;非对称荷载会对瓦斯抽采造成不利影响,使得在均布荷载条件下的抽采达标时间增加。通过调整非对称荷载环境下的抽采半径,不仅提高大约3%的抽采效率,还可以确保在180天内满足抽采标准,从而有效提升瓦斯抽采的整体性能。To reveal the influence of asymmetric load on gas seepage and extraction radius,a multi-physics coal and gas fluid-solid coupling model was proposed to analyze the gas seepage characteristics of coal seams.Matrix-adsorbed gas was used as the mass source in the proposed model introducing asymmetric loads into the boundary conditions.Furthermore,segmented drilling was used under asymmetric load conditions to optimize the gas extraction radius and improve extraction efficiency.The results indicated that greater stress compressed the cracks inside the concentrated stress zone,making it more difficult for gas to flow and to be extracted more challenging.The gas pressure in the concentrated stress zone decreased by approximately 2%less than that in the original stress zone,and the permeability decreased by about 9%.Asymmetric load had different degrees of influence on the diffusion and seepage processes.Within 180 days,the mass of diffused gas of the original stress area decreased by 19%and the seepage mass decreased by 20.5%,while these values in the concentrated stress zone decreased by 16.9%and 17.9%,respectively.Asymmetric loads had adverse effects on gas extraction,increasing extraction time under uniform load conditions.By adjusting the extraction radius under asymmetric load conditions,not only can the extraction efficiency be improved by approximately 3%,but it can also ensure that the extraction standards are met within 180 days,thereby effectively improving the overall performance of gas extraction.

关 键 词：非对称荷载 煤层瓦斯 瓦斯渗流 抽采半径 瓦斯抽采 渗透率 

分 类 号：X936[环境科学与工程—安全科学]