Nanoscale mineralogy and organic structure characterization of shales: Insights via AFM-IR spectroscopy

Abstract

Atomic force microscopy coupled with infrared spectroscopy (AFM-IR) is one of the most effective and widely employed mixed techniques capable of providing direct access to infrared spectroscopic imaging and chemical analysis at the nanoscale spatial resolution. In this communication, AFM-IR was applied to the evaluate the in-situ nanoscale mineralogy and to characterize the organic structure of shale. Significant chemical and microstructural heterogeneity could be observed on the mirror-like surface of naturally deformed shale. It was also apparent that slickensides formed on the mirror-like surface potentially influence the spatial distribution of organic matter. This technique provides an effective combination for direct and in-situ studies of the morphology and physicochemical properties of geological rocks at the nanoscale, opening a new avenue for investigations to help reveal some complex geological phenomena, such as organic carbon graphitization and mineral transformation during fault deformation. Furthermore, this technique makes it possible to determine the chemical composition, molecular structure and functional group information of shale organic matter, which is crucial information for investigating the hydrocarbon generation potential, maturity evaluation, and oil and gas migration mechanisms in shale.

Document Type: Short communication

Cited as: Zhu, H., Lu, Y., Pan, Y., Qiao, P., Raza, A., Liu, W. Nanoscale mineralogy and organic structure characterization of shales: Insights via AFM-IR spectroscopy. Advances in Geo-Energy Research, 2024, 13(3): 231-236. https://doi.org/10.46690/ager.2024.09.08

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