Recently, thermal recovery technologies such as combustion have been studied for shale gas recovery. Thus, understanding of the microstructure of combusted shale is essential for evaluating the effects of thermal treatment on shale gas transport capacity. In this study, the effect of combustion on shale microstructure changes was investigated. Firstly, different-sized shale samples were combusted at 450 °C for 30 min. Afterward, shale microstructure properties including surface topographies, porosity and permeability of the raw and combusted shale samples were measured and compared. It was found that the pore volume and specific surface area increased after combustion, especially for small pulverized samples. According to surface topography obtained from atomic force microscope, more rough surfaces were obtained for the combusted shale due to larger pores and generation of thermal fractures caused by the removal of organic matter. Based on the mercury intrusion porosimetry measurements, the porosity of the shale samples increased from 2.79% to 5.32% after combustion. In addition, the permeability was greatly improved from 0.0019 to 0.6759 mD, with the effective tortuosity decreased from 1075.40 to 49.27. As a result, combustion treatment can significantly improve the gas transport capacity.

中文翻译：

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热提高页岩气回收率：燃烧后的页岩的微观结构特征

最近，已经研究了诸如燃烧的热回收技术以用于页岩气的回收。因此，了解可燃页岩的微观结构对于评估热处理对页岩气传输能力的影响至关重要。在这项研究中，研究了燃烧对页岩微结构变化的影响。首先，将不同尺寸的页岩样品在450°C下燃烧30分钟。然后，测量并比较了原始和燃烧的页岩样品的页岩微观结构特性，包括表面形貌，孔隙率和渗透率。发现燃烧后孔体积和比表面积增加，特别是对于小粉碎的样品。根据从原子力显微镜获得的表面形貌，由于较大的孔隙和由于去除有机物而引起的热裂缝的产生，燃烧后的页岩获得了更多的粗糙表面。根据压汞法测量，燃烧后页岩样品的孔隙度从2.79％增加到5.32％。此外，渗透率从0.0019 mD大大提高到0.6759 mD，有效曲折度从1075.40降低到49.27。结果，燃烧处理可以显着提高气体输送能力。有效曲折度从1075.40降低到49.27。结果，燃烧处理可以显着提高气体输送能力。有效曲折度从1075.40降低到49.27。结果，燃烧处理可以显着提高气体输送能力。