Deeper insights into oxygen-containing compounds of the Mandal Formation, Central Graben, Norway

Beside the kerogen composition, the amounts of generated bitumen play a major role when assessing the petroleum retention and expulsion behavior of a source rock. High-molecular weight (HMW) products dominate the source rock extracts during early stages of generation in the TOC-rich, inefficiently expelling Mandal Formation. Such GC-unresolvable, bituminous compounds have not yet been structurally described. Based on 20 immature to peak-oil mature whole rock samples from different locations of the Central Graben, a compositional comparison of seven samples of different maturity stages is drawn to the excellently expelling Posidonia Shale, Germany of similar maturity. ESI negative FT-ICR-MS allows to investigate the acidic heteroelemental interior of the in-source retained petroleum. Rather than the quantities of bitumen, its composition seems to be important for petroleum migration efficiency and fractionation. While Posidonia Shale extracts contain slightly higher proportions of NSO constituents than ext...