Experimental study of kerogen maturation by solid-state 13C NMR spectroscopy.

Highlights: [•] Сobs decreases during the artificial maturation experiments. [•] Branched aromatic carbons transform into bridgehead aromatic carbons. [•] –(CH2)–O–C structures in kerogen break up at the early stages of catagenesis. [•] The spatial remoteness of alkyl chains from aromatic cores is fixed up to the oil window. [ABSTRACT FROM AUTHOR]