多孔灰岩局部化变形的精细化描述与数字表征  

Detailed Description and Digital Characterization of Strain Localization in Porous Limestone

作　　者：武岳彪 孟范宝 王岳军 Patrick Baud 黄庭芳 WU Yuebiao;MENG Fanbao;WANG Yuejun;Patrick Baud;WONG Tengfong(School of Earth Sciences and Engineering,Sun Yat-sen University,Zhuhai 519082,Guangdong,China;Earth and Environmental Sciences,Faculty of Science,The Chinese University of Hong Kong,Hong Kong SAR 999077,China;Universitéde Strasbourg,CNRS,Institute Terre et Environnement de Strasbourg,UMR 7063,5 Rue RenéDescartes,Strasbourg Cedex 67084,France;Department of Geosciences,Stony Brook University,Stony Brook,NY 11794,USA)

机构地区：[1]中山大学地球科学与工程学院,广东珠海519082 [2]香港中文大学理学院地球与环境科学课程,中国香港999077 [3]Universitéde Strasbourg,CNRS,Institute Terre et Environnement de Strasbourg,UMR 7063,5 Rue RenéDescartes,Strasbourg cedex 67084,France [4]Department of Geosciences,Stony Brook University,Stony Brook NY 11794,USA

出　　处：《大地构造与成矿学》2024年第3期547-556,共10页Geotectonica et Metallogenia

基　　金：中山大学高校基本业务费‒青年教师培育项目(23qnpy19);香港研究资助局项目(GRF14323916)联合资助。

摘　　要：压实带是一种典型的应变局部化现象,影响储层流体的封存、输运以及地下岩体的稳定性。多孔灰岩局部化变形的相关研究一直是难点,不像砂岩样品可以通过明显的声发射信号特征来分析与表征压实带的形成与演化规律。本文利用动态CT技术,实时监测灰岩局部化变形到宏观失稳的演化过程,重点描述压实带形成初期的局部化变形特征,涵盖了应变量>5%的变形部分特征。在灰岩变形过程中可以识别两处明显非弹性变形阶段:即初始大孔隙坍塌阶段和后续压实带形成过程,利用图像体积互相关技术定量表征压实带的演化特征,精细化描述压实带形成过程的微观破裂特征,系统分析离散压实带内的连通孔隙分布规律,发现连通孔隙与局部化变形有紧密联系,并基于CT扫描的孔隙网络数据,利用纳维斯特斯方程计算绝对渗透率,以渗透率为参考指标,研究局部化变形引起的损伤程度。The compaction band is a phenomenon of strain localization that influences reservoir fluid storage,transportation properties,and rock stability.Research on strain localization in porous limestone is much more challenging than that in sandstone because of the lack of consistent acoustic emission activity for analyzing the formation and evolution of strain localization in limestone.In this study,synchrotron in situ X-ray Computed Tomography imaging(CT)is performed to infer the multi-scale dynamics of compaction localization and failure as it is triaxially compressed.We here focus on the deformation characteristics at the initial stage of the compaction band,where the strain is greater than 0.05.Two inelastic compaction stages were identified in the stress-strain curve:macropore collapse followed by the sequential growth of compaction bands.Digital volume correlation(DVC)was used to characterize the growth of the compaction band and to analyze the micro mechanism of failure during the compaction band.The interconnected pore network in the distinct compaction bands was strongly correlated with strain localization.Based on the calculated pore distribution results,simplified Navier-Stokes equations were solved to numerically estimate the absolute permeability.As an index,the permeability can be used to quantify damage to the transportation properties caused by strain localization.

关 键 词：局部化变形 CT技术 灰岩 孔隙网络 

分 类 号：TD313[矿业工程—矿井建设]