Gaseous products of organic matter thermal decomposition depending on the type of kerogen

Abstract

The aim of the research was to ascertain the possibility of determining the type of kerogen based on gaseous products of pyrolysis of rocks containing organic matter. The relationship between the type of kerogen and the obtained gas products is important in assigning an appropriate role to the source rocks in the process of modeling petroleum systems. 13 rock samples were analyzed, representing type I, II and III kerogen, classified by the Rock Eval analysis. Thermogravimetry coupled with Fourier Transform Infrared Spectroscopy (TG-FTIR) was used for evaluation of thermal decomposition and pyrolysis gaseous products determination. It was stated that the most appropriate temperature for which gas detection should be recorded and compared is 450 and 510^oC. Determining the composition of gas released in the process of pyrolysis of rocks containing organic matter, as well as the temperatures at which the maximum emission occurs allows the characterization of the type of kerogen and its maturity. FTIR spectra for rocks containing type I kerogen are characterized by the presence of a methane (CH₄) peak, significant intensities of C-H stretching vibrations and the presence of C=O vibrations. During the pyrolysis of rocks containing type II kerogen, methane peaks are low, but CO₂ is intensively released, and the structures of aromatic hydrocarbons disintegrate, as indicated by C=C vibrations. In the FTIR spectra of rocks representing type III kerogen, the methane (CH₄) peak and C=C vibrations at temperatures of 450 and 510^oC are most often absent, and the CO₂ peaks are characterized by low intensity.

Document Type: Original article

Cited as: Labus, M., Matyasik, I. Gaseous products of organic matter thermal decomposition depending on the type of kerogen. Advances in Geo-Energy Research, 2025, 15(1): 44-54. https://doi.org/10.46690/ager.2025.01.05

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