Journal Article Microstructural Analysis of the Transformation of Organic Matter during Artificial Thermal Maturation of the Upper Cretaceous Boquillas (Eagle Ford) Formation, Texas, USA Get access Wayne K Camp, Wayne K Camp Anadarko Petroleum Corporation, The Woodlands, TX, USA Search for other works by this author on: Oxford Academic Google Scholar Wayne Knowles, Wayne Knowles Weatherford Laboratories, Bideford, Devon, UK Search for other works by this author on: Oxford Academic Google Scholar Kultaransingh Hooghan, Kultaransingh Hooghan Weatherford Laboratories, Houston, TX, USA Search for other works by this author on: Oxford Academic Google Scholar Tim E Ruble Tim E Ruble Weatherford Laboratories, Houston, TX, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 23, Issue S1, 1 July 2017, Pages 2128–2129, https://doi.org/10.1017/S1431927617011308 Published: 04 August 2017

The organic carbon residue present in retorted oil shale and high maturity source rocks consists of a combination of recalcitrant substances including thermally degraded kerogen, char and pyrobitumen. Differentiating the relative contribution of each material is important to understanding the chemical properties of spent shale for reclamation, beneficial reuse and gas storage potential. It is also needed to facilitate the development of robust geochemical models of hydrocarbon-generating systems. Standard chemical methods used to assess residual carbon content typically cannot distinguish between these materials despite their differing origins. In this study, we apply a combination of analytical techniques to provide greater insight into the nature of the carbonaceous materials in spent oil shale. Spent shale from low temperature (360°C) openand closed-system retorting experiments were analyzed by high temperature programmed pyrolysis (HT-PPy, up to 800°C) following different heating times in order to assess the change in the relative amount of each residual carbon type present. The HT-PPy pyrograms of the samples retorted under closed, high-pressure conditions become more complex relative to the raw shale as heating time increases. Pyrobitumen was distinguished from heavy oil residue, thermobitumen and residual kerogen by differences in degradation temperature, much like free oil and natural bitumen (S1) are differentiated from kerogen (S2) by the Rock-Eval method. Char content was estimated based on the carbon-13 nuclear magnetic resonance-determined aromaticity of the residue. The results are supplemented by Fourier transform infrared spectroscopy and compared to bulk analysis.