| Autor: |
Hatcherian, Javin, Adsul, Tushar, Hackley, Paul, Ghosh, Santanu, Varma, Atul Kumar |
| Předmět: |
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| Zdroj: |
Bulletin of the Geological Society of Greece; 2023 Special Issue, p70-70, 1p |
| Abstrakt: |
Hydrocarbon generation occurs within thermally mature, organic-rich sediments and is influenced by a variety of mineral assemblages and relative mineral abundances. Some elements sourced from minerals have been shown to act as strong catalysts during hydrocarbon generation. Previous laboratory experiments conducted by Ma et al. (2016) suggested that the lone electron pair of sulfur bonded to iron(II) in synthetic pyrite enhanced free radical formation through hydrogen transfer from kerogen to sulfur. In this work, we examine the impact of sulfur in catalysis by conducting a series of hydrous pyrolysis (HP) experiments at varying temperatures and pyrite abundances to investigate how sulfur sourced from pyrite facilitates early hydrocarbon generation and thermal maturation. To examine the impact of sulfur in catagenesis over a range of temperatures, 1 g of gilsonite (a solid hydrocarbon) was mixed with 0.1 to 10 g of reagent-grade pyrite. Aliquots of these mixtures and aliquots of untreated gilsonite underwent HP at temperatures of 320°C, 350°C, and 370°C for 72 hours. Aliquots of untreated gilsonite and the HP residues of gilsonite/pyrite mixtures were analyzed by reflectance measurements, LECO carbon analyzer for total organic carbon (TOC) and programmed temperature pyrolysis via Hydrocarbon Analyzer with Kinetics (HAWK). The results indicated solid bitumen reflectance was higher in HP residues with greater pyrite concentrations for the lower temperature HP residues (320°C and 35O°C), while reflectance values were similar in the 370°C residues, regardless of pyrite concentration. This result may suggest a greater catalytic effect at lower thermal conditions influenced by C-S and S-S bond dissociation. Samples with the highest concentration of pyrite consistently contained the lowest Hydrogen Index (HI) values among samples undergoing similar HP conditions. Conversely, Production Index (PI) values were higher in samples with higher concentrations of pyrite. These results from gilsonite reflectance, HI, and PI support the hypothesis that the presence of catalytic sulfur enhances thermal maturation through a free radical mechanism. However, HP residues with the highest concentrations of pyrite had lower Tmax values. These results will be discussed with respect to the relative abundance of pyritic sulfur in source rocks and its potential to act as a catalytic agent during burial maturation. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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