断裂组合汇聚脊对渤海湾盆地南堡凹陷油气藏的控制作用OA

With continued exploration in the Nanpu Sag,Bohai Bay Basin,hydrocarbon exploration is facing problems such as unclear hydrocarbon distribution patterns and great difficulty in making discoveries.Exploration has confirmed that faults play an important role in controlling hydrocarbon accumulation in this area,but the related mechanisms remain unclear.Based on detailed interpretation of 3D seismic data,this study systematically summarizes the characteristics of fault assemblages in the Nanpu Sag.The hydrocarbon accumulation theory of"convergence ridges"was introduced to study the characteristics of deep fault-assemblage convergence ridges in the Paleogene Shahejie Formation and their reservoir-controlling effects on shallow hydrocarbon reservoirs in the Neogene Minghuazhen and Guantao formations.Combined with exploration practice in the Liunan area,a shallow hydrocarbon accumulation model was established for this area,and favorable exploration directions were defined.As indicated by the research results,the profile assemblage types of deep faults in the Nanpu Sag can be divided into four types:synthetic adjustment type,antithetic adjustment type,synthetic/antithetic fault-step type,and graben-horst type.The plane assemblage types can be divided into four types:synthetic parallel/branching type,antithetic parallel/branching type,synthetic parallel/en echelon type,and alternating synthetic-antithetic parallel/en echelon type.Deep fault-assemblage convergence ridges can be classified into three types:fault-sand type in the steep slope belt,intra-sag uplift type in the sag area,and low-uplift type in the slope belt.Deep fault-assemblage convergence ridges have important controlling effects on shallow hydrocarbon reservoirs.These effects are reflected in three aspects:the dual"conduit-guidance"control on hydrocarbon migration,the synergistic"trap-enrich-ment"effect on hydrocarbon accumulation,and the"barrier-stability"protection of hydrocarbon reservoir preser-vation.This study suggests that the Gaoliu fault plays an important role in controlling shallow hydrocarbon accu-mulation in the Liunan area.A shallow hydrocarbon accumulation model of"fault-sand type convergence ridge controlling reservoirs in the steep slope belt"was established for the Liunan area.This model can scientifically explain the complex hydrocarbon distribution patterns in this area.It is inferred that the Liuxi structure,the eastern side of block L25,and shallow channel sands on the western-wing slope setting of Liu 102,which are located in the favorable hydrocarbon migration zone of the convergence ridge,are favorable exploration areas for the next stage in the study area.