Fault Accommodation Zones and Their Controling Effects on Hydrocarbon Distribution in Yong 8 Fault Block,Dongying Sag

Based on the study of fault geometry,kinematics,and dynamics in Yong 8 fault block using 3-d high-resolution seismic data with oil field geological data,we discovered an east-west striking synthetic-overlapping fault accommodation zone.The western side of the major fault(Xin 120 Fault) with adjusting faults shows a step-style structural pattern,and the eastern side of the major fault(Yong 105 Fault) with adjusting faults shows a horst-style structural pattern.When Xin 120 fault activity becomes weak,Yong 105 Fault and adjusting faults accommodate the displacement.Stress field of Yong 8 accommodation zone is left-lateral,transextensional.Through the analysis of distribution and source of Yong 8 fault block,characteristics of fault activities,and fault sealing properties,we constructed the accumulation model of Yong 8 block fault.The eastern side of the major fault is oil source fault which connected the source and the reservoir,and migrated hydrocarbon during the main hydrocarbon accumulation period,and adjusting faults stopped activities in the earlier period,formed fault traps,and became barrier faults.Western part of Yong 8 fault block is the target region for progressive exploration and development.