基于全直径CT扫描技术的礁灰岩孔隙结构研究

Study on pore structure of reef limestone based on full-diameter core CT scanning technique

为研究南海岛礁礁灰岩微观孔隙结构特征并进行定量分析,运用X射线CT扫描设备对礁灰岩试样进行扫描;对扫描数据重建处理,得到高分辨率三维数字岩芯。运用三维可视化软件Dragonfly对数字岩芯进行可视化处理,通过阈值建立孔隙和基质的二元结构模型,计算得到礁灰岩试样的整体孔隙率及逐层面空隙率。采用最大球算法计算得到礁灰岩连通孔隙的球棒模型。结果表明:礁灰岩的整体孔隙率为7.47%~8.24%,更接近致密砂岩;逐层面孔隙率离散性均较大,呈现出非常明显的非匀质特性。研究成果可为珊瑚礁灰岩渗透特性和力学特性的深入研究提供基础。

In order to study the micro-pore structure characteristics of the reef limestone in the South China Sea and conduct quantitative analysis,the reef limestone samples were scanned with X-ray CT scanning equipment.High-resolution 3D digital core model was obtained by reconstructing the scanned data.Digital core was visualized by using the three-dimensional visualization software Dragonfly,and the binary structure model of pores and substrate was established through thresholding.The whole porosity of the reef limestone specimen and its layer-by-layer porosity were calculated.The ball-bat model of the connected pores of reef limestone was obtained by calculating the maximum ball algorithm.The calculations showed that the overall porosity of reef limestone was from 7.47%to 8.24%,which was closer to the compact sandstone.The layer-by-layer porosity showed great discreteness and a very obvious non-homogenous feature.The research results can provide a basis for further study of the permeability and mechanical properties of coral reef limestone.