Study On Structural Features Of The Maxi Fault Zone In Raoyang Depression

Based on the analysis of seismic data,geological data,logging data and drilling data,this paper analyzed the strike-slip characteristics of the Maxi fault zone in the northeastern part of Raoyang depression,by the combination of macro and micro analysis,from qualitative to quantitative research.Firstly,the fault structure and the combination pattern were described in detail,and the extensional tectonic pattern and strike-slip tectonic pattern were studied in detail.On this basis,the quantitative evaluation of tectonic activity intensity was carried out.And then,the structural evolution of the strike-slip tectonic movement was analyzed,and the control factors of the strike-slip tectonic movement on hydrocarbon accumulation in this area was analyzed.Through research,the Maxi fault zone mainly developed the extensional tectonic patterns of skewed block(alice),sliding fault,reverse traction anticline and buried hill drape anticline,and the strike-slip tectonic patterns of the flower structure,flower goose and broom construct style.By plotting the tectonic evolution profile,the characteristics of the Cenozoic tectonic evolution in the area were analyzed.Es3 and Es1 periods were the main activity period of the Maxi fault zone.Based on the qualitative analysis of tectonic activity,the quantitative evaluation of tectonic activity intensity was carried out.Based on the geological survey of the research area,the parameters of fault growth index and fault throw were selected to study the structural activity of the Maxi fault zone.And the strike-slip displacement was analyzed by using the seismic profile data,and then the structural activity of the Maxi fault zone is evaluated quantitatively.In the end,the main activity of Maxi fault zone was divided into five stages.Ek-Es4 stage is the main event of the Maxi fault.In Es3 stage,the study area was affected by the northwest-south eastward extension,and the eastern plate of the Maxi fault firstly formed a small number of secondary faults toward the near northeast.Es2 stage was for the western secondary fault formation by the new generation of dextral.The Es1-Ed period is a strong and continuous activity stage of the fault,and the typical broom-like structure in the south of the Maxi fault zone was developed.The Neogene-Quaternary was a stage of weak fault activity intensity.The mechanism of the Maxi fault zone was further studied by constructing the physical simulation experiment.The simulation results show that the Maxi fault had a secondary fault formation in the eastern ascending plate under the early extension.And then the secondary strike-slip effect was applied to the model in the later stage.The secondary faults were formed in the west of the Maxi fault zone.The intensity of the dextral strike-slip activity is further increased,and a number of secondary faults are formed at the end of the Maxi fault and converge to the southern end of the Maxi fault,forming a typical broom on the plane and flower-shaped structure visible in the section.The results of the physical simulation experiment were compared with the previous structural analysis results,and the results were highly consistent.Finally,combined with the characteristics of oil and gas distribution in the study area,the control factors of the strike-slip tectonic evolution of the Maxi fault zone on hydrocarbon accumulation was briefly analyzed from the aspects of structural traps,hydrocarbon migration and hydrocarbon accumulation patterns.It is found that the reservoir formation model in this area is a model of single faulting compound migration and accumulation.