DOMINANT FACTORS TO THE NEOGENE HYDROCARBON CCUMULATION ON MIDDLE OF BONAN LOWER-UPLIFT

Breakthroughs of hydrocarbon exploration have been made in the Neogene in the middle part of the Bonan lower-uplift over the last two years. The study of hydrocarbon accumulation patterns upon latest exploration achievements, geological and geophysical data and testing results suggest that there are three controlling factors over oil and gas accumulation in the region. The distance of reservoir to source controls the reservoir size; the existence of long-lived faults, which cut down to the buried hill, provide pathways for hydrocarbon migration in the Neogene; and the position of reservoirs within the 'cabbage'-type fault system plays a critical role in hydrocarbon enrichment. These understandings lead to the proposal of the model of stepped lateral migration from distant oil sources for hydrocarbon accumulation on the Bonan lower-uplift, which are of great significance to the exploration of Neogene hydrocarbon in the study area.