Shah S M, Crawshaw J P, Boek E S
Qatar Carbonates and Carbon Storage Research Centre (QCCSRC), Department of Chemical Engineering, Imperial College London, London, U.K.
J Microsc. 2017 Feb;265(2):261-271. doi: 10.1111/jmi.12496. Epub 2016 Oct 25.
In the last decade, imaging techniques capable of reconstructing three-dimensional (3-D) pore-scale model have played a pivotal role in the study of fluid flow through complex porous media. In this study, we present advances in the application of confocal laser scanning microscopy (CLSM) to image, reconstruct and characterize complex porous geological materials with hydrocarbon reservoir and CO storage potential. CLSM has a unique capability of producing 3-D thin optical sections of a material, with a wide field of view and submicron resolution in the lateral and axial planes. However, CLSM is limited in the depth (z-dimension) that can be imaged in porous materials. In this study, we introduce a 'grind and slice' technique to overcome this limitation. We discuss the practical and technical aspects of the confocal imaging technique with application to complex rock samples including Mt. Gambier and Ketton carbonates. We then describe the complete workflow of image processing to filtering and segmenting the raw 3-D confocal volumetric data into pores and grains. Finally, we use the resulting 3-D pore-scale binarized confocal data obtained to quantitatively determine petrophysical pore-scale properties such as total porosity, macro- and microporosity and single-phase permeability using lattice Boltzmann (LB) simulations, validated by experiments.
在过去十年中，能够重建三维（3-D）孔隙尺度模型的成像技术在研究流体通过复杂多孔介质的流动过程中发挥了关键作用。在本研究中，我们展示了共聚焦激光扫描显微镜（CLSM）在对具有油气藏和二氧化碳储存潜力的复杂多孔地质材料进行成像、重建和表征方面的进展。CLSM具有独特的能力，能够生成材料的三维薄光学切片，在横向和轴向平面上具有宽视场和亚微米分辨率。然而，CLSM在多孔材料中可成像的深度（z维度）方面存在限制。在本研究中，我们引入了一种“研磨和切片”技术来克服这一限制。我们讨论了共聚焦成像技术应用于包括甘比尔山和凯顿碳酸盐岩在内的复杂岩石样品的实际和技术方面。然后，我们描述了将原始三维共聚焦体积数据滤波和分割为孔隙和颗粒的完整图像处理工作流程。最后，我们使用所得的三维孔隙尺度二值化共聚焦数据，通过格子玻尔兹曼（LB）模拟定量确定岩石物理孔隙尺度特性，如总孔隙度、大孔隙度和微孔隙度以及单相渗透率，并通过实验进行验证。
