Kerogen alteration

Combined stable isotope analysis ( C, D, N, has been used successfully in petroleum exploration (Stahl 1977 Schoell 1984 Sofer 1984). The isotopic composition of crude oil is mainly determined by the isotopic composition of its source material, more specifically, the type of kerogen and the sedimentary environment in which it has been formed and by its degree of thermal alteration (Tang et al. 2005). Other secondary effects like biodegradation, water washing, and migration distances appear to have only minor effects on its isotopic composition. 

The figure 2/3 is the dimension of the specific surfaces such as the case of the sublimation rate of mothball in the air. However, the presence of non-carbonate minerals and organic structures (kerogen matrix) which separate the carbonate mineral into isolated sites connected by channels would alter the rate so that ... 

Stricktly speaking, kerogens are always inhomogeneous and always contain impurities" such as graphite particles, carbon-black carbonaceous particles at various degrees of metamorphic alteration and mineral impurities. An electron microscope is a particularily suitable tool for studying these phases present in kerogens, since particles less than 1 pm can be examined (Oberlin et al., 1980) 19). 

The IR spectra of these kerogens show high concentrations of carbonyl and carboxyl groups indicating strong oxidation of the organic matter. This alteration... 

We should caution that the above concept of the genetic relationship between kerogens and asphaltenes differs from the more historic view that asphaltenes are condensation and/or alteration products of hydrocarbons and resins. Certainly, in some petroleum processing treatments and probably at higher maturation levels in nature, various reactions do form new products with asphaltene solubility characteristics. These new condensation products may be regarded as altered asphaltenes and intermediates in the coke or pyrobitumen formation process (62-64)- Contamination of original asphaltenes by subsequently formed or altered products, of course, will result in a less definitive correlation between an asphaltene and its source kerogen. 

This significant alteration of Tg is explained by the fact that commercial Kerogene 70 is delivered with an additive (10-15% green oil), to improve fire safety during transportation. We can assume that the green oil plays the role of a polystyrene surfactant plasticizer . 

Hydrous pyrolysis experiments of crude oils generated relatively large concentrations of mono-and dicarboxylic acid anions with relative abundances generally similar to those observed in sedimentary basin waters. But analysis of all of the pertinent data indicates that the major part of the organic acid anions in formation waters is probably generated by the thermal alteration of kerogen in source rocks (Kharaka et al., 1993b Lewan and Fisher, 1994). This conclusion is based on several observations ... 

What chemical alterations have occurred during kerogen transformation Give an example of a van Krevelen diagram. 

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