煤岩裂隙网络水气运移特性数值模拟研究  

Numerical simulation study on the migration characteristics of water and gas in coal rock fracture networks

作　　者：林强伟 朱永建 罗亚飞[1,2,3] 李鹏 王平 李豹 LIN Qiangwei;ZHU Yongjian;LUO Yafei;LI Peng;WANG Ping;LI Bao(School of Resources,Environment and Safety Engineering,Hunan University of Science and Technology,Xiangtan Hunan,411201,China;Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Goal Mines,Hunan University of Science and Technology,Xiangtan Hunan 411201,China;Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines,Hunan University of Science and Technology,Xiangtan Hunan 411201,China)

机构地区：[1]湖南科技大学资源环境与安全工程学院,湖南湘潭411201 [2]南方煤矿瓦斯与顶板灾害预防控制安全生产重点实验室,湖南湘潭411201 [3]湖南科技大学煤矿安全开采技术湖南省重点实验室,湖南湘潭411201

出　　处：《矿业科学学报》2025年第1期125-136,150,共13页Journal of Mining Science and Technology

基　　金：国家自然科学基金(52274119,52304214);湖南省自然科学基金青年基金(2023JJ40287)。

摘　　要：为了研究煤岩真实裂隙网络中水驱气的运移特性,采用体视显微镜提取现场煤样的二维裂隙结构,二值化后导入COMSOL软件中进行水驱气数值模拟,采用相场法对水气两相界面进行追踪,探讨水驱气过程中封闭气形成原因,分析不同裂隙数量与裂隙开度对驱替效果的影响。结果表明:当裂隙延伸方向与驱替方向一致时,驱替速度更快,易形成优势通道,经过狭窄喉道时速度和压力增加;在驱替平衡时,易形成盲端封闭气、“H”型封闭气、变径封闭气和绕流封闭气4种封闭气类型,其形成主要受裂隙形态、毛细管力及润湿性影响;裂隙数量减少时,水气两相平均速率增大,平均压力与剩余瓦斯量减小;裂隙开度较小时,平均速率和压力升高,剩余瓦斯量增加。To investigate the transport dynamics of water-driven gas displacement within the intrinsic fracture network of coal,this study extracted the two-dimensional fracture structure of in-situ coal samples using a stereomicroscope.Following binarization,the fracture images were imported into COMSOL software for numerical simulation of water-driven gas displacement.We employed the phase field method to track the water-gas two-phase interface,allowing for a detailed examination of the mechanisms behind trapped gas formation.Additionally,we analyzed the impact of varying fracture densities and aper-tures on displacement effectiveness.The findings indicate that when the fracture extension direction aligns with the displacement direction,displacement velocity is enhanced,facilitating the formation of preferential flow channels;in narrow throat sections,both velocity and pressure increase.At displace-ment equilibrium,four types of trapped gas structures—blind-end,“H”-type,variable-diameter,and bypass trapped gastend to form,influenced primarily by fracture morphology,capillary forces,and wettability.With fewer fractures,the average water-gas flow rate increases,reducing both average pres-sure and residual gas content;in contrast,narrower apertures elevate both flow rate and pressure,resulting in higher residual gas levels.This micro-scale study of water-driven gas displacement within real coal fracture networks offers insights for improving gas displacement efficiency at the macro scale.

关 键 词：裂隙网络 煤层注水 数值模拟 剩余气 运移特性 

分 类 号：TD712[矿业工程—矿井通风与安全]