Characteristics of Soluble Organic Matter Combined with <2 μm Clay Size Fraction of Source Rocks and Its Significance

Abstract:

In order to investigate the relationship between soluble organic matter (SOM) and clay size fraction,SOM extracted from source rock and <2 μm clay size fraction (separated by a physical approach from source rock) were analyzed.The results show that a large amount of SOM are combined with clay minerals and it is an important occurrence in source rocks.The rate of SOM production is higher in clay size fraction compared with that in source rock,and <2 μm clay size fraction plays an important role in each period of hydrocarbon generation.The composition of SOM in clay size fraction exhibits as domination in nonhydrocarbon and asphaltene groups and depleted in polar lipid fractions including saturated hydrocarbon and aromatic components compared with SOM extracted from source rocks.It can be concluded that organoclaymineral is a potential material of oil generation throughout the whole progress of hydrocarbon generation.

Key words:source rocks; <2 μm clay size fraction; soluble organic matter; preservation of organic matter; hydrocarbon generation