Source rock and asphaltene biomarker characterization by pyrolysisgas chromatography-mass spectrometry-multiple ion detection

Biomarkers produced by microscale pyrolysis of extracted source rocks, kerogens and asphaltenes have been analysed directly by gas chromatography-mass spectrometry in the MID mode. A series of experiments have been undertaken. These include an investigation into the production of the hopanes at different pyrolysis temperatures and a comparison of results obtained from Curie point pyrolysis and the Chemical Data Systems pyroprobe. Steranes and triterpanes produced by pyrolysis of a series of vitrinites were investigated and correlated with maturity variations. Finally, the biomarkers produced from asphaltenes were compared with those produced from the extract and extracted rock in order to further investigate the theory that asphaltenes are a liquid kerogen. The results of these experiments showed that the biomarkers released by pyrolysis of source rocks have a potential use for source and maturity determinations. The method is advantageous in that it can be said with some certainty that the biomarkers are indigenous to the rock and not present in the rock as a possible result of migration.