Relationship between distribution, hydrocarbon generation and evolution of source rock in Haerjiawu formation and Carboniferous hydrocarbon accumulation in Malang sag, Santanghu Basin

Key words:  hydrocarbon kitchen  biomarker  accumulation period  period of hydrocarbon generation  nitrogenous compounds

Abstract:

By using a series of techniques such as logging-seismic source rock prediction, basin simulation, oil and source rock correlation, and crude oil migration tracing, the distribution and hydrocarbon generation evolution of Haerjiawu formation source rock, geochemical features of Carboniferous crude oil and source rock, and the migration patterns of crude oil in Malang sag were studied. The results show that the source rock of Carboniferous oil in Malang sag mainly has two types of occurrence patterns, namely normal sedimentation and sedimentation of clastic rocks. There are four symbiotic relationships between source rock and volcanic rock. The Carboniferous crude oil in Mazhong tectonic belt is of high maturity, while that of Niudong tectonic belt is mature. The Carboniferous crude oil of Niudong tectonic belt is mainly generated by the local mature source rock in the northern slope of Malang sag, and large-scale hydrocarbon generation started during the middle-late Cretaceous and migrated from east to west. The oil and gas of Mazhong tectonic belt is generated by the high mature source rock in the center of the sag.