Atomic Force Microscopy-based Infrared Spectroscopy Data within Immature Eagle Ford Shale at the Nanometer-scale
The nanoscale molecular composition of kerogen is a challenging parameter to characterize given the chemical and structural complexity exhibited by this important biopolymer. However, kerogen composition will strongly impact its reactivity and so is a critical parameter to understand petroleum generation processes during kerogen catagenesis. The recent advent of tip-enhanced analytical methods, such as atomic force microscopy-based infrared spectroscopy (AFM-IR), has allowed for the major compositional features of kerogen to be elucidated at spatial resolutions at or below 50 nm. Here we apply AFM-IR to examine inertinite, an important kerogen maceral type, from an immature Eagle Ford Shale sample. Our data show...
Nanoscale Molecular Composition of Solid Bitumen from the Eagle Ford Group Across a Natural Thermal Maturity Gradient
Solid bitumen is a petrographically-defined secondary organic matter residue produced during petroleum generation and subsequent oil transformation. The presence of solid bitumen impacts many shale reservoir properties including porosity, permeability, and hydrocarbon generation and storage, amongst others. Furthermore, solid bitumen reflectance is an important parameter for assessing the thermal maturity of formations with little to no vitrinite. While the molecular composition of solid bitumen will strongly impact associated parameters such as the development of organic matter porosity, hydrocarbon generation, and optical reflectance, assessing the molecular composition of solid bitumen in situ within shale reservoirs...
Strain induced molecular heterogeneity in ancient sedimentary organic matter mapped at nanoscales using optical photothermal infrared spectroscopy
Here we report ultra-high resolution infrared mapping of organic matter functional group distribution in Tasmanites (algal microfossils) from the Upper Devonian Ohio Shale using optical photothermal infrared spectroscopy (O-PTIR). O-PTIR is capable of rapidly measuring the vibrational response of samples in situ with ~500-nm spatial resolution, well below the infrared diffraction limit. Our results indicate that organic matter within the fold apices regions (zones of greatest deformation) of relatively large Tasmanites is more aliphatic and less oxygen-rich than organic matter in the surrounding Tasmanites body. This contrasts with data from relatively thinner Tasmanites which show statistically invariant chemical...