基于SEM图像灰度水平的页岩孔隙分割方法研究  

Pore Segmentation Methods Based on Gray Scale of Scanning Electron Microscopy Images

作　　者：王羽[1,2] 金婵[1,2] 汪丽华[1,2] 王建强[1,2] 姜政[1,2] 王彦飞[3] 

机构地区：[1]中国科学院微观界面物理与探测重点实验室 [2]中国科学院上海应用物理研究所上海光源 [3]中国科学院地质与地球物理研究所

出　　处：《岩矿测试》2016年第6期595-602,共8页Rock and Mineral Analysis

基　　金：中国科学院战略性先导科技专项(B类)"页岩三维成像实验技术和数据获取技术"(XDB10020102);国家杰出青年科学基金资助项目(41325016)

摘　　要：微观孔隙结构是研究页岩气吸附运移机制和建立地质模型的基础,氩离子抛光-扫描电子显微镜(SEM)技术是开展此项研究的主要实验方法,但已有的研究大多是关注页岩孔隙分类,较少从定量角度表征其特征。为开展页岩微观孔隙结构定量研究,提高孔隙分割质量,本研究分别利用边缘检测分割法、流域分割法、手动和自动阈值分割法对页岩无机孔和有机孔二次电子图像进行分割实验,对比不同方法的分割效果。结果表明,通过选取合适的分割阈值,基于SEM图像的手动阈值分割法能够表征1 nm以上的孔隙,准确地识别有机质与脆性矿物边缘、孔隙与有机质边缘,使得页岩孔隙提取结果趋近于真实,能更有效地对页岩孔隙结构进行定量分析。Microscopic pore structures of shale are the basis for investigating the adsorption and migration mechanism of shale gas and building a geological model.Ar ion milling combined with Scanning Electron Microscopy（ SEM） is the main technique for analyzing microscopic pore structures of shale. However, previous research focused mainly on pore classification and lacked insufficient studies on the quantitative characteristics of pore structures. In order to conduct quantitative research on pore structures and improve the quality of pore segmentation, edge detection, watershed, auto and manual thresholding methods were used in this study to perform segmentation of mineral matrix pore and organic matter pore based on SEM images. By comparing results obtained from all of these methods,the conclusion drawn was that the manual thresholding method could reflect pores with diameters larger than 1 nm and identify the organic matter,pores and brittle minerals accurately by selecting a suitable segmentation thresholding value,guaranteeing the analysis to be closer to the true states. The proposed method provides a more effective method for quantitative analyses of shale pore structures.

关 键 词：富有机质页岩 SEM图像 孔隙分割 阈值法 

分 类 号：P619.227[天文地球—矿床学] P575.2[天文地球—地质学]