Research On Fault System And Reservoir Control In The Banqiao Area,Qikou Sag

Based on 3D seismic,physical simulation and laboratory analysis in the Banqiao area of Qikou sag,this paper analyzes the geometric and kinematic characteristics of faults,defines the superposition deformation relationship and deformation mechanism of faults,and classifies fault systems from the perspective of "system theory".Combined with the coupling relationship among the accumulation period,the hydrocarbon source and fault systems,three types of accumulation control function are defined.Firstly,hydrocarbon source faults control the vertical dominant migration channel along the fault.Based on the understanding of the internal structure of the fault zone and the difference in physical properties of different structures,combined with the tracer evidence and the study of fault activity,using the combination of fault plane geometry and kinematic multi-attribute calculation,the method of delineating the vertical dominant migration channel along the source fault was established.Secondly,the accumulation fault control the lateral sealing of fault.Based on the observation and description of the internal structure of the fault zone in the coring well,it is believed that mudstone daub and fault-gouge fault rock are widely distributed in Banqiao area,which is a typical fault rock sealing mechanism.And then,based on the fine anatomy of the known 16 fault-type reservoirs,the actual overfault pressure difference of the fault was determined,and the SGR-AFPD relationship of multiple drilled fault reservoirs was calibrated in the target section.The critical chart of fault lateral closure evaluation was constructed by using statistical method.The critical SGR was 18.3%.The SGR method can effectively determine the enrichment degree of fault traps.Thirdly,the adjusting fault mainly control the vertical closure.Based on laboratory experiments and reservoir dissection,a qualitative assessment method for brittle-ductile of the cap was established.The regional cap of Es1 in the study area shows brittle and ductile deformation characteristics,while the regional cap of Nd shows obvious brittle deformation characteristics.The SSF method and the cutoff thickness method was applied to to evaluate the vertical closure of faults.Through the calculation,the critical SSF value was 3.14-3.19 and the critical cutoff thickness value was 70-80 m.Under the guidance of the fault-control theory,the controlling effect of fault growth evolution on hydrocarbon accumulation was systematically discussed from the perspective of fault growth mechanism:1.Segmented growth and evolution of fault control the migration of depression;2.Determining the timing validity of fault trap from the perspective of fault segment growth and evolution;3.Based on the quantitative evaluation results of three types of fault,the effectiveness evaluation of fault traps in Banqiao area was carried out.