Schlumberger-Doll Research Center, Cambridge, MA, 02139, USA.
U.S. Geological Survey, Reston, VA, 20192, USA.
Nat Commun. 2017 Dec 19;8(1):2179. doi: 10.1038/s41467-017-02254-0.
Solid organic matter (OM) plays an essential role in the generation, migration, storage, and production of hydrocarbons from economically important shale rock formations. Electron microscopy images have documented spatial heterogeneity in the porosity of OM at nanoscale, and bulk spectroscopy measurements have documented large variation in the chemical composition of OM during petroleum generation. However, information regarding the heterogeneity of OM chemical composition at the nanoscale has been lacking. Here we demonstrate the first application of atomic force microscopy-based infrared spectroscopy (AFM-IR) to measure the chemical and mechanical heterogeneity of OM in shale at the nanoscale, orders of magnitude finer than achievable by traditional chemical imaging tools such as infrared microscopy. We present a combination of optical microscopy and AFM-IR imaging to characterize OM heterogeneity in an artificially matured series of New Albany Shales. The results document the evolution of individual organic macerals with maturation, providing a microscopic picture of the heterogeneous process of petroleum generation.
固体有机质 (OM) 在经济上重要的页岩岩层中烃类的生成、运移、储存和生产中起着至关重要的作用。电子显微镜图像记录了 OM 在纳米尺度上的孔隙度的空间异质性，而体光谱测量记录了 OM 在石油生成过程中化学成分的巨大变化。然而，关于 OM 化学成分在纳米尺度上的异质性的信息一直缺乏。在这里，我们展示了基于原子力显微镜的红外光谱 (AFM-IR) 在纳米尺度上测量页岩中 OM 的化学和机械异质性的首次应用，其空间分辨率比传统的化学成像工具（如红外显微镜）高几个数量级。我们结合光学显微镜和 AFM-IR 成像来表征人工成熟的一系列新奥尔巴尼页岩中的 OM 异质性。结果记录了单个有机母质随成熟度的演化，为石油生成的异质过程提供了微观图像。
