The Surface Of Oil-source Faults And Its Influence On Hydrocarbon Migration And Accumulation

During an earthquake,most of the deformation occurs on the main slip plane within the fault zone.At present,researches on fault surface topography are mainly focused on the field of natural seismic research,and its influence on the generation and termination of earthquakes is analyzed.Any wild natural fault surface outcrop,it shows the geometry and appearance characteristics are as a result,the effect of internal and external forcing in fact fault surface morphology research more truly reflect the tectonic evolution process and the characteristics of rock mechanics on the detailed research can more accurately reflect the influence of oil and gas migration and accumulation.For quantitative analysis of fault surface roughness on the influence of oil and gas migration and accumulation,in the prophase of Qikou sag in the fracture system,this paper has a detailed classification and to set on the basis of oil and gas source faults,based on the fine 3D seismic data,3D geological modeling,and fault surface geometry,kinematics attribute extraction,on the basis of quantitative characterization of the fault plane surface morphology,determine the advantage of oil and gas migration channel and influence on oil and gas migration and trap formation,eventually establish a favorable zones optimization evaluation principle.First of all,on the basis of predecessors' study,through the method of field observations,3D seismic data,well data and biomarker compound,it is concluded that there are four fault systems in shahejie formation of qinan slope,including shasan~guantao-minghuazhen fault system,shayi~dongying fault system,shasan~shaer~shayi-dongying fault system and shasan-shaer fault system.Among them,the active fault system of shasan~guantao-minghuazhen fault system is the most important oil-gas source fault,and there are three main qinan slopes,namely nandagang fault,zhangbei fault and zhaobei fault.Secondly,fault surface topography plays an important role in controlling oil and gas migration.Based on the analysis of the geometric and kinematic characteristics of the three main faults in the study area and the 3D geological modeling of the fault surface,the geometric and kinematic properties of the fault plane were extracted,it is concluded that when the asperity on the fault surface meet four conditions at the same time as the advantage of oil and gas migration channels:(1)Fault activity is stronger,slippery momentum is bigger,it represents fault zone activity space in the larger area with high porosity.(2)Geometric properties such as surface gradient,dip and strike are all high values,it represents the abrupt change zone of the asperity;(3)The curvature is the high value and represents the fracture zone;(4)The high value of the shear strain represents that the upper mudstone cover position is easy to destroy.The distribution area of dominant channels in the study area has a good correspondence with oil and gas reservoirs.In addition,the fault surface topography plays an important role in controlling the accumulation of oil and gas.The surface roughness value of the fault plane was calculated by the trend surface analysis method,in which the asperity of the fault plane corresponded to the positive roughness area,which usually controlled the location of fault trap-fault line deflection fold development,and the traps were usually developed in the high roughness area.Finally,based on the above studies,it can be concluded that the study of fault plane morphology can not only further improve the theoretical study of fault transmission,but also provide guidance for the exploration and deployment of dagang oilfield.