A novel upscaling procedure for characterising heterogeneous shale porosity from nanometer-to millimetre-scale in 3D
A novel upscaling procedure for characterising heterogeneous shale porosity from nanometer-to millimetre-scale in 3D
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DOI：
10.1016/j.energy.2019.06.011
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发表时间：
2019-08
期刊：
影响因子：
9
通讯作者：
Lin Ma;P. Dowey;E. Rutter;K. Taylor;Peter D. Lee
中科院分区：
文献类型：
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作者：
Lin Ma;P. Dowey;E. Rutter;K. Taylor;Peter D. Lee
页岩中的微观结构和孔隙系统是理解页岩在许多能源应用中的作用的关键。本研究提出了一种新的多阶段放大程序，全面调查的非均质和复杂的微观结构和孔隙系统的层状和微裂缝页岩，利用三维多尺度成像数据。五种成像技术用于表征从亚纳米级到宏观尺度（核心尺度），跨越四个数量级。使用X射线断层扫描、聚焦离子束和电子断层扫描技术收集的图像数据的体素尺寸范围为0.6 nm至13 μm。在放大之前，进行了一种新的两步分析，以确保子样本具有代表性。在此之后，一个三步的程序，均化描述符和计算的体积系数的基础上，被用来放大的量化的微观结构和孔隙系统。在最高分辨率（纳米级），四个不同的孔隙类型被确定。在亚微米尺度下，推导了三个孔隙相关相的方程。在微尺度下，重新计算体积系数，使孔隙系统扩大到毫米尺度.验证了放大方法的准确性，预测总孔隙度的偏差在7.2%以内。这些结果为理解非均质岩石类型提供了一个独特的视角，突破了孔隙系统中先前的尺度限制。
Microstructures and pore systems in shales are key to understanding the role of shale in many energy applications. This study proposes a novel multi-stage upscaling procedure to comprehensively investigate the heterogeneous and complex microstructures and pore systems in a laminated and microfractured shale, utilising 3D multi-scale imaging data. Five imaging techniques were used for characterisation from sub-nanoscale to macroscale (core-scale), spanning four orders of magnitude. Image data collected using X-ray tomography, Focused Ion Beam, and Electron Tomography techniques range in voxel size from 0.6 nm to 13 μm.Prior to upscaling, a novel two-step analysis was performed to ensure sub-samples were representative. Following this, a three-step procedure, based on homogenising descriptors and computed volume coefficients, was used to upscale the quantified microstructure and pore system. At the highest resolution (nanoscale), four distinct pore types were identified. At the sub-micron scale equations were derived for three pore-associated phases. At the microscale, the volume coefficients were recalculated to upscale the pore system to the millimetre- scale. The accuracy of the upscaling methodology was verified, predicting the total porosity within 7.2% discrepancy. The results provide a unique perspective to understand heterogeneous rock types, breaking though prior scale limitations in the pore system.