Structural Characteristics And Its Relationship To Hydrocarbon Enrichment In Fulin Sag

As a secondary structural unit of Bohai Bay Basin,Fulin sag has experienced multi-stage of structural deformation and evolution,forming a complex fault system.This dissertation,based on fine structural interpretation of seismic dat,combined with integrated regional geology,drilling,logging and other related information,using balanced cross section,structural analysis,basin analysis and other research methods and techniques,resolved deep layers development,structural charactristics and stratigraphic evolution,as well as the relationship between Fulin Sag strutural geology and oil gas enrichment,based on which we evaluated favorable exploration zones and target zones.Structural styles developed in Fulin sag include four categories,which are extensional Structural style,compressional Structural style,strike-slip Structural style and superimposed Structural style.Superimposed Structural style can be devided into cutting type and negative inversion Structural stype.Structure superimposed extents from east to west,from strong to weak.Fulin sag's structural framework is mainly controled by Kenli fault,Kendong faults and Guxi fault,whose normal faulting were started in Cretaceous,intensed in Paleogene,ended in Miocene,among which the activity of Kenli fault is greater in southern part than northern part,the activity of Kendong fault is greater in middle and eastern part than western part,Guxi fault occurs mainly negative inversion(normal fault)activity on the basis of the early thrust fault and its activity level is strong in the southeast part than the northwest.Fulin sag and its adjacent area has gone through four major tectonic evolution stages since Cenozoic:(1)-Indo movement in middle-Late Triassic caused the early intracontinential orogenic uplift stage and erosion;(2)Mountain basin in Jurassic and early Yanshan movement casued late intracontinential orogenic stage;(3)Post orogenic extensional collapse in Cretaceous and its effects to reversed phase;(4)Large-scale extension and rifting overall depression basin development stage in Cenozoic,among which the first two stages are mainly charactaristics by extrusive shorten deformation with continential orogenic and crustal thickening movemen,the latter two stages are extensional deformation,crust and lithospheric thinning.Fulin sag's oil and gas are mainly from lower shasan section,middle subsag.According to the study of a major regional fault activity analysis and structural transformation zone,we figured out that faults in this section,especially the border area are large fault vertical hydrocarbon migration main channel,structural transformation band provides good traps,forming the mainly block reservoirs.