Tracing the origin of petroleum using asphaltene carbon isotope ratios: Case study from the Songliao Basin, NE China

Abstract

Type I and II kerogens, isolated from outcrop shales in the Songliao Basin, were performed a programed sealed-heating kinetic process. Both carbon isotope values of pyrolysis-residual kerogens and those of asphaltene extractions present gradual enrichments dependence on increasing Easy %Ro and biomarker maturity ratios. The carbon isotope (δ¹³C) values are used for the first time to analyze a close relationship between these kerogens and asphaltenes at the same level of thermal maturation, and identification oil–source rock correlation studies in theory. Such validity of the model was further tested by δ¹³C of asphaltenes and biomarker ratios in crude oils.

Keywords:

• asphaltene
• carbon isotope ratios
• kerogen
• oil-source rock correlation
• pyrolysis

Acknowledgment

We especially thank Dr. Li Wang and Daqing Oilfield Co. for their help in sampling.

Additional information

Funding

This study was financially supported by the Fundamental Research Funds for the Central Universities (lzujbky-2018-6), State Key Laboratory of Organic Geochemistry, GIGCAS (No. SKLOG-201809) and the Foundation for National Science of China (No. 41621062 and 41730421).