A great number of extensional and strike-slip faults of various orientations and scales occur in the offshore Bohai Bay Basin

eastern China.Complex areal and vertical combinations exist between these faults and they play a key role in hydrocarbon accumulation in this area.Based on seismic interpretation and structural mapping

this paper mainly focuses on the regional and local interaction patterns of the extensional faults and strike-slip faults and their significances for hydrocarbon accumulation in the study area.On map view

the regional patterns of fault interaction involve conjugate type

orthogonal crossing type and oblique crossing type

while the local patterns of fault interaction can be divided into broom-shaped transfer type

branch transfer type

en-echelon fault transfer type and transition structure transfer type

of which the last type can be subdivided into three sub-types including ramp

horst type and faulted-block.On sectional view

the fault interaction patterns mainly include X-shaped type

hybrid type and superposition type.The fault interaction not only influences basin architecture

but also impactes trap

reservoir and hydrocarbon migration.This study is of great significance for oil and gas exploration in the offshore Bohai Bay Basin.