Abstract:

The Tanlu fault zone was very active in the process of the Neotectonic movement.Although the tecto-nic movement was intense,several medium-and large-sized oil fields were formed in the Bozhong-Bonan segments of the Tanlu fault zone,indicating that fault activity played a key role in the migration and accumulation of hydrocarbons during this period.This paper,starting with the activity differences between the major and secondary faults in different tectonic settings,uses the fault activity rate (FAR) method to analyze and summarize the relationship between fault activities and hydrocarbon migration & accumulation during the Neotectonic period and to reveal the mechanism of late hydrocarbon accumulation in the study area.The results show that fault activities vary across different segments of the zone.The main faults with weaker activities are favorable for hydrocarbon accumulations,while those with stronger activities are the opposite,as it is easy for hydrocarbons to escape.A combination of active main faults with secondary faults of weaker activity is considered good for hydrocarbon migration,accumulation,and preservation.

Key words: fault activity rate, Neotectonics, hydrocarbon accumulation, Tanlu fault zone, Bozhong-Bonan area, Bohai Bay Basin