Abstract:

In order to further clarify the role of different geological conditions in hydrocarbon accumulation process, we researched the main controlling factors of hydrocarbon accumulation of Fuyang Formation in Sanzhao depression  based on the angle of diverse geological conditions and their relation in space-time. The result showed that the bound, distance and layer of hydrocarbon migrated downward were controlled by effective expulsion range of K₁qn¹ source rock, overpressure and T₂ fault assemblage. The direction, pathway and distance of the migrated oil were controlled by palaeostructure and the relationship between T₂ fault and reservoir. Vertical and lateral distribution of oil and gas were controlled by the factors of base level, sedimentary microfacies and recent tectonic. Based on those mentioned above coupled with structural history, oil sources conditions, sedimentary microfacies, four kinds of hydrocarbon accumulation models were summarized, they are, (a)inside source-upper source rock-lower reservoir model, (b)near source-short distance lateral migration-fault screened in slope zone model, (c)outside source-long distance lateral migration-inherited tectonic uplift zone model and (d)ulti-source-multi-lateral migration model.

Key words: Songliao basin, Sanzhao region, Fuyang units, petroleum gas, hydrocarbon accumulation model, key controlling factors