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Pyrolysis Mass Spectrometry: Instrumentation, Techniques, and Applications
Published in Karen D. Sam, Thomas P. Wampler, Analytical Pyrolysis Handbook, 2021
C. J. Maddock, T. W. Ottley, Thomas P. Wampler
The characterization of sedimentary organic matter in terms of type and maturity is a prerequisite in the determination of the petroleum-generating potential of sediments. The nonextractable material—kerogen—consisting of Complex high-molecular-weight fragments, when subjected to Py-MS and multivariate analysis, gives excellent discrimination into the three universally recognized types [25]. Coals [26,27] have been studied extensively from the standpoint of product formation and structure. The organic material in soils has also been investigated by pyrolysis-MS, including contributions from plants to soil carbon [28], humic acids [15] and fatty acids [29].
Spectroscopic Characterizations of Humic Acids Isolated from Diverse Arctic Environments
Published in Neloy Khare, Climate Change in the Arctic, 2022
The sedimentary organic matter undergoes a combination of physical, chemical and biological processes resulting in an early diagenetic state. In this stage, the sedimentary system transforms both in terms of quantity and composition of organic matter. The pathway for this transformation from a starting material to the final products through the intermediates is always a challenge to organic geochemists and biogeochemists. Various studies on the diagenetic pathways reported providing information regarding the diagenetic alteration and transformation of precursor organic molecules (Henrichs 1992).
Organic geochemical characteristics of Middle to Late Eocene Shahbazan Formation in Dezful Embayment, SW Iran: A case study from Qaleh-Nar oilfield
Published in Petroleum Science and Technology, 2019
Bahram Alizadeh, Seyed Rasoul Seyedali, Bahram Habibnia
The process of hydrocarbon generation is mainly a function of thermal maturity. Sedimentary organic matter is converted to petroleum by temperature enhancement during increase in burial depth. The pyrolysis maturity data, including Tmax and PI, are considered to be the most important indicators to determine the level of thermal maturity (Peters and Cassa 1994). Cross-plot of PI versus Tmax (Figure 4) indicates that the studied samples are thermally mature and have already entered the oil window. Carbon preference index (CPI) achieved by GC analysis, is the other indicator of maturity. The value of this parameter is either remarkably above or considerably below 1 in thermally immature rocks, while it approaches 1 by increasing maturity (Peters, Walters, and Moldowan 2005). CPI ranges from 1.07 to 1.3 for the studied samples (Table 2), indicating that they are thermally mature.
Geochemical characterisation of the Xiagou Formation carbonate-bearing mudstone in southwestern Jiuquan Basin, China: implications for paleo-environment reconstruction and the origin of organic matter
Published in Australian Journal of Earth Sciences, 2018
G. Chen, W. Z. Gang, N. Wang, L. Y. Zhao
Sedimentary organic matter is the most important factor in petroleum accumulation, and organic matter controls the quantity of generated hydrocarbon and hydrocarbon components in a petroliferous basin. Organic matter in source rock ultimately generates hydrocarbon with measurable quantities of biomarkers. In addition, major- and trace elements are incorporated into hydrocarbon source rocks in the form of complex precursors, which have a direct connection with the paleo-environment during sedimentation. Diagenesis from organic molecules and trace metals derived from different biogenic and abiogenic sources may also be relevant (Akinlua, Torto, & Ajayi, 2008). The abundance of organic matter depends on numerous factors, including biological productivity, paleoclimate, cataclysm events, water column salinity, redox condition and deposition rate (Chen, Zhang, Sun, & Wu, 2006; Sun et al., 2013; Zonneveld et al., 2010). Biomarkers and metal elements in crude oil and organic sedimentary rocks with abundant organic matter can be used to reconstruct the paleo-environment and study the origin of the organic matter (Ajayi, Torto, Tchokossa, & Akinlua, 2009; Akinlua et al., 2008; Moldowan, Seifert, & Gallegos, 1985). Major- and trace metals have been demonstrated to be useful paleo-environmental redox indicators (Tribovillard, Algeo, Lyons, & Riboulleau, 2006).