| Bohai Bay Basin is a Cenozoic petroliferous basin located in the eastern continental margin of China.In this paper,Bonan low uplift and its northern adjacent area are located in the central area of Bohai Bay Basin.In recent years,several large and medium-sized oil and gas fields such as BZ19-6 and KL9-1 have been discovered in Bonan low uplift and its northern adjacent area,which shows good exploration potential of this area.Based on the previous research results,this paper focuses on the analysis of the structural deformation and evolution characteristics of the Bonan low uplift and its northern adjacent area by the fine interpretation of 3D seismic data,and the impact of fault activity on formation and deposition,which is helpful for oil and gas exploration in the study area.The EW,NE and NW trending faults are developed well in the Bonan low uplift and its northern adjacent area.The faults are mainly shovel-type and plate-type in profile and linear and arc-shaped in plane.In the section,the faults are composed of "Y" type and ladder type,and in the plane,the faults are mainly composed of echelon type and parallel type.The typical structural styles mainly include horst,graben and dustpan structure.Based on the statistics and calculation of accumulations of main faults by using multiple survey lines,combined with the analysis of equilibrium profile,it is found that the activity rates of the same fault are different in different periods and locations,and the activity of the fault is most intense in the late Eocene.The tectonic evolution can be divided into the initial rifting stage of Paleocene-Middle Eocene,the strong rifting stage of late Eocene and the fault-depression transition stage of Oligocene.The fault activity in the study area also has an important influence on the stratigraphic deposition.During the deposition period of Kongdian Formation and Sha-4Member,two basement faults controlling the boundary of the low uplift were developed in the western part of Bonan low uplift,and fan deltas were mainly developed.During the sedimentary period of Sha-3 Member the boundary faults of Bonan low uplift were strongly active and controlled the formation deposition,and fan deltas were distributed on both north and south sides of the whole low uplift.During the sedimentary period of Sha-1 Member、Sha-2 Member and Dongying Formation,the fault activity became weaker and the braided river delta was mainly developed. |
