Long-Term, Low-Temperature Simulation of Early Diagenesis of Organic Matter from Algae: Significance for Immature Oil.

Algae are good sources of immature oil. A long-term (more than 5 years), low-temperature (80°C) simulation of early diagenesis of organic matter from algae was carried out. In the very early stage of the simulation, different quantities of immature oil were generated after 26 to 56 days. After one year, algae showed obvious fluorescence, and the intensity was maintained during the remainder of the simulation. From the earlier stages of the simulation to the later stages, the asphaltene fractions of the soluble extracts decreased and the polar fractions increased. Asphaltene and polar compounds play important roles in the formation of immature oil, especially under briny environments. Finally, the changes in hydrocarbons during the simulation are discussed and the algae-originated phytenes and C20bicyclic terpanes are suggested as biomarkers for immature oil. [ABSTRACT FROM PUBLISHER]