基于显微CT技术的结焦砂3维孔隙结构精细表征  

Advanced characterization of three-dimensional pores in coking sand by micro-CT

作　　者：史琳[1] 许然[1] 许强辉[1] 须颖 郑立才 SHI Lin XU Ran XU Qianghui XU Ying ZHENG Licai(Key Laboratory of Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China Sanying Precision Instruments Ltd. , Tianjin 300000, China)

机构地区：[1]清华大学热科学与动力工程教育部重点实验室,北京100084 [2]三英精密仪器有限公司,天津300000

出　　处：《清华大学学报（自然科学版）》2016年第10期1079-1084,共6页Journal of Tsinghua University(Science and Technology)

基　　金：国家创新团队支持项目(51321002)

摘　　要：结焦带的结焦情况是影响稠油火烧油层技术开发成效的重要因素。目前该领域对于焦炭分布情况和结焦量的研究停留在2维表面观察和宏观实验参数测定,无法深入描述稠油火烧过程作用机理和进行较准确的数值模拟。显微CT技术作为一种无损获得材料内部微观结构信息的技术已经开始应用于石油地质领域。该文利用油层高温高压反应模拟实验装置在实验室环境下获得结焦砂样品,并利用显微CT技术得到结焦样品孔隙尺度的3维重构图像。该研究通过选择适当的扫描参数获得相对较高对比度的灰度图,再通过分水岭分割法和Chen-Vese模型算法对CT灰度图进行图像分割,得到表征孔隙、焦炭和模拟砂的3维重构图。为了验证图像的真实性,采用TGA热重分析仪和真密度计进行实验验证,并通过建立表征函数证明显微CT3维重构图像的真实性和合理性。该研究为稠油火烧油层领域结焦量、结焦量与孔隙度关系以及多孔介质渗流模拟研究提供基础。Coke formation is very important for in-situ oil combustion. Previous studies of the coke distribution and coke content for in-situ combustion have used two-dimensional surface observations and macro parameter measurements that cannot accurately describe the mechanisms for the burning of heavy oil which limits the accuracy of numerical simulations. X-ray microtomography （micro-CT） has been used as a non-destructive technique to characterize the material＇s microstructure for petroleum geology. This paper describes micro-CT measurements of coking sand samples in a laboratory to reconstruct three dimensional pore scale images. These measurements give relatively high contrast gray scale images with the watershed segmentation method and the Chen-Vese model algorithm used to construct the three dimensional images of the pores coke or in sand. The images are verified against data from TGA and densitometer measurements with good agreement. This method provides excellent models for analyzing the coke content, the relationship between the porosity and the coking content, and even for porous media fluid flow simulations of in-situ combustion.

关 键 词：显微CT 火烧油层 焦炭 图像处理 

分 类 号：TK123[动力工程及工程热物理—工程热物理]