复杂方解石脉充填煤岩细观损伤演化特性研究  

Characterization of mesoscopic damage evolution in complex calcite vein-filled coal rocks

作　　者：邬忠虎 夏茜 王文涛 唐摩天 雷文丽 孟祥瑞 WU Zhonghu;XIA Xi;WANG Wentao;TANG Motian;LEI Wenli;MENG Xiangrui(College of Civil Engineering,Guizhou University,Guiyang,Guizhou 550025,China;Yongfeng County Comprehensive Transportation Business Development Centre,Ji’an,Jiangxi 343000,China;China Electric Power Construction Group Zhongnan Survey and Design Institute Co.,Ltd.,Changsha,Hunan 410014,China;Hunan Zhongnan Hydropower and Water Conservancy Engineering Construction Co.,Ltd.,Changsha,Hunan 410014,China)

机构地区：[1]贵州大学土木工程学院,贵州贵阳550025 [2]永丰县综合交通运输事业发展中心,江西吉安343000 [3]中国电建集团中南勘测设计研究院有限公司,湖南长沙410014 [4]湖南中南水电水利工程建设有限公司,湖南长沙410014

出　　处：《油气藏评价与开发》2024年第6期942-951,958,共11页Petroleum Reservoir Evaluation and Development

基　　金：国家自然科学基金项目“黔北下寒武统页岩多期裂缝形成机理及分布预测模型研究”(52104080);贵州省科技支撑计划项目“六盘水地区煤层气储层渗透机制及压裂缝网优化改造关键技术研究与示范”(2021401);贵州省科技计划项目“贵州省页岩气效益开发关键技术及工程试验”(2022ZD005)。

摘　　要：为探索单轴作用下煤岩内部方解石复杂形态的破坏特征,通过薄片观察煤岩内部方解石脉充填形态,采用分形维数来描述方解石形态的复杂程度,利用二维真实破裂过程细观分析软件对不同形态下的方解石煤岩进行了单轴压缩数值模拟实验。结果表明:方解石复杂程度对煤岩细观损伤演化特性极其敏感,峰值强度随着方解石分形维数的增大整体呈现增大的趋势;裂缝率和峰值应力二者呈正相关,最终破坏时产生的峰值强度越高,其对应的裂缝率也越高。此外在单轴压缩过程中,方解石脉颗粒周边首先出现很多微小裂缝,断裂延伸方向和方解石脉走向几乎一致,影响煤岩的裂缝延伸方向。分形维数越大,声发射计数数量越多,煤岩破坏也越复杂。研究成果有助于深入认识方解石脉分布形态对煤岩力学性质的影响,并为研究含方解石脉煤岩细观损伤演化规律提供了新的方法。To investigate the failure characteristics of calcite veins with complex morphologies in coal rock under uniaxial compression,thinsection observation was used to examine the calcite vein filling within coal rock.Fractal dimension analysis was applied to quantify the complexity of calcite morphology.Numerical simulations of uniaxial compression tests on coal rock containing calcite veins of varying morphologies were conducted using a two-dimensional real failure process mesoscopic analysis software.The results revealed that the complexity of calcite morphology significantly affected the mesoscopic damage evolution characteristics of coal rock.The peak strength generally increased with the fractal dimension of the calcite veins.A positive correlation between crack rate and peak stress was observed,indicating that higher peak strengths corresponded to higher crack rates at final failure.During uniaxial compression,multiple microcracks initially appeared around the calcite vein particles,with fracture propagation directions closely aligned with the vein orientation,influencing the crack propagation direction in the coal rock.Additionally,coal rock with larger fractal dimensions exhibited more acoustic emission events,signifying more complex failure patterns.These findings contribute to a deeper understanding of how calcite vein distribution affects the mechanical properties of coal rock and provide a novel approach to studying the mesoscopic damage evolution in coal rock containing calcite veins.

关 键 词：煤岩 细观 方解石脉 分形维数 破坏 

分 类 号：TE37[石油与天然气工程—油气田开发工程]