Study of thermal maturation processes of sulfur-rich source rock using compound specific sulfur isotope analysis

•Organic sulfur compounds (OSC) were evaluated in source rock artificial maturation.•δ34S of OSC in the oil phase provide insight to the chemical structure of kerogen.•Diagenesis and catagenesis tends to lower the variability in the δ34S of the OSC.•Depletion in the δ34S of the H2S is small and not concurrent with δ34S of OSC.•The δ34S of the OSC is used for oil-source rock correlation on crude oil samples.