Syn-depositional fault control on hydrocarbon migration and accumulation pattern: a case study from Tangbei Area, Bohai Bay Basin, NE China

Tangbei Area, a complex syn-depositional fault development area, is located in petroliferous Bohai Bay Basin with abundant petroleum resources in the Paleogene. The way to figure out possible migration pathways and potential accumulation accommodation controlled by syn-depositional faults has become a key issue for predicting favorable reservoirs. Based on seismic volume and wireline logs, we carried out fine seismic interpretation, document the faults and their combinations in plane view and section view, and reveal its influence on hydrocarbon migration and accumulation. The results indicate that fine seismic interpretation in the study area provides the distribution and characteristics of syn-depositional faults generated by regional tectonic activities. In addition, syn-depositional faults play an important influence on basin structure and the pathways and traps for hydrocarbon migration and accumulation. Three types of syn-depositional faults are divided based on their locations. It is found that syn-depositional faults in steep slope zone are much favorable for hydrocarbon migration and accumulation. Syn-depositional faults in different depositional periods throughout basin evolution act as pathways for hydrocarbon migration, as well as act as seals, which depend on surrounding lithology associations and sealing or leaking properties through time.