Volatile organic acids generated from kerogen during laboratory heating

Abstract

Low molecular weight organic acids were studied in the course of pyrolysis experiments (200-400°C, 2-1, 000h) of kerogen (Green River Formation and Monterey Formation) with and without the presence of water and minerals (montmorillonite, illite and calcite). C₁-C₁₀ aliphatic acids and benzoic acid were identified in the pyrolysis products of kerogen. Their distribution. is characterized by a dominance of acetic acid followed by formic and propionic acids with an even/odd preference in the range of C₄-C₁₀. Total concentrations of these acids amounted to 0.3% of initial kerogen, indicating that kerogen has a good potential for producing organic acids. Geochemical implications of these organic acids are; (1) they are possible intermediates from kerogen to natural gas (CO₂, H₂, CH₄, C₂H₆, etc.) by decarboxylation, and (2) they may be important and potential contributors to the generation of secondary porosity by dissolving minerals.