Experimental Characterization of Oil Shales and Kerogens
- Extract kerogen and bitumen from Green River oil shale
- Obtain experimental structural data, including but not limited to 13C solid state NMR, on Green River oil shale, on bitumen and kerogen isolated from the shale, and on products of pyrolysis of these materials
Department of Energy, National Energy Technology Laboratory
The first goal of this project is to isolate the organic matter from the oil shale, which constitutes approximately 10-20% of the total shale. This includes the soluble bitumen as well as the insoluble kerogen. This demineralization is a lengthy process, comprised of a number of acid washes and extractions.
The second goal is to experimentally characterize the structure of the organic material. To achieve this goal, the following experimental techniques are being employed on these samples: 13C nuclear magnetic resonance (NMR) spectroscopy in solution and in the solid state, mass spectrometry (MS) analysis, small angle x-ray scattering (SAXS), and measurement of the atomic pairwise distribution function (PDF) via x-ray scattering. Each of these techniques provides different information on the structure of the materials.
Figure 1 is one example of the data obtained on these samples. The figure shows the 13C solid state NMR data obtained on the shale from three different sections of the Institute for Clean and Secure Energy's (ICSE) Skyline 16 oil shale core. This core was drilled in Utah's Uinta Basin. This data can be analyzed to obtain information such as the percentage of carbons that are aromatic versus aliphatic, the average number of carbons in an aromatic cluster, and the percentage of aromatic carbons that are protonated, substituted or bridgehead carbons
Figure 1: Solid-state 13C NMR data of three different sections (GR-1,-2,-3, numbers indicate depth along core) of the Skyline 16 core from the Uinta Basin, Utah. While the spectra appear to be quite similar, a full NMR analysis of each sample reveals differences.
In addition to the analysis performed as part of this project, the isolated kerogen is also provided to other projects within the Institute for Clean and Secure Energy (e.g. CT microscopy and pyrolysis experiments). All pyrolysis products (tars, chars, etc.) will be returned to this research group to undergo the same characterization as the original material in order to determine the changes in the material.
The experimental data generated by this project will be used by another ICSE project, Atomistic Modeling of Oil Shale Kerogens and Oil Sand Asphaltenes, to assess the quality of an atomic level model of the kerogen and to guide model modification.
Orendt, Anita M.; Birgenheier, Lauren P.; Solum, Mark S.; Facelli, Julio C.; Pugmire, Ronald J.; Locke, Darren; Chapman, Karena; Seifert, Soenke; Winans, Randall; Chupas, Peter, Detailed Characterization of Green River Oil Shale Segments and Isolated Kerogen, October 2011
Orendt, Anita M.; Birgenheier, Lauren P.; Solum, Mark S.; Pugmire, Ronald J.; Facelli, Julio C.; Locke, Darren; Chapman, Karena; Seifert, Soenke; Winans, Randall; Chupas, Peter, Structural Characterization of Green River Oil Shale Core Segments and the Kerogen Isolated from these Segments, 18, September 2011