Shale comparative characterization

Comparative Characterization and Hydrotreating Response of Coal, Shale, and Petroleum Liquids... 

Analytical separation and spectroscopic techniques normally used for petroleum crudes and residues were modified and used to characterize coal liquids, tar sands bitumens, and shale oils. These techniques include solvent extraction, adsorption, ion-exchange, and metal complexing chromatography to provide discrete fractions. The fractions are characterized by various physical and spectroscopic methods such as GLC, MS, NMR, etc. The methods are relatively fast, require only a few grams of sample, provide compound type fractions for detailed characterization, and provide comparative compositional profiles for natural and synthetic fuels. Additional analytical methods are needed in some areas. 

Higher temperatures are characteristic of the sedimentary section of the Akfadou area as compared to the Takhoukht area. Temperatures of about 120 °C were reached in Early Devonian sediments. Our model calculations for the end of the Early Carboniferous (about 330 Ma), and before the Hercynian uplift and erosion, give temperatures and maturation levels for the Ordovician, Silurian, and Early Devonian shales consistent with early to main stages of hydrocarbon generation (Table 6.6). Toward the close of the Carboniferous (about 289 Ma), the sapropelic and humic organic matter of the Ordovician, Silurian, and probably Devonian source shales was sufficiently mature to generate both liquid and gaseous hydrocarbons. Silurian and Devonian shales in other areas of the basin are also characterized by considerable potential... 

Note Information presented in this table, such as original gas-in-place and technically recoverable resources, is presented for general comparative purposes only. The numbers provided are based on the sources shown and this research did not include a resource evaluation. Rather, publicly available data was obtained from a variety of sources and is presented for general characterization and comparison with other shale gas plays. Resource estimates for any basin may vary greatly depending on individual company experience, data available at the time the estimate was performed, and other factors. Furthermore, these estimates are likely to change as production methods and technologies improve. 

Further evidence for the ability of chemical processes within the shale to retard important radionuclides, is provided by the distribution of Ce and Ba. These elements are chemical analogues for the radiologically important elements Th and Ra respectively, which are important constituents of many radioactive wastes. The elevated levels of Ce and Ba in the shale matrix, compared to the levels in the calcite veins (Table 2) may be evidence that these elements were relatively immobile during the formation of the calcite veins. An implication is that Th and Ra would also have been relatively immobile under these conditions (undisturbed far-field conditions). Such investigations require, however, better characterization of the mineral sinks for Ba, Ce and other trace elements, and determination of the calcite crystallization mechanisms. 

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