Seismic Technique For Identifying Minor Fault Applied In The Slope Zone Of Shawan Depression

With the improvement of exploration request in oil-gas field and the development of geophysical technique,the exploration target inevitably changes from conventional oil-gas field to unconventional oil-gas field,in which fault block pool and fracture type reservoir become more and more popular.In such kind of oil-gas field,minor fault plays a very important role,especially in thin reservoirs.Since minor fault has really small scale,and its breakpoint unobvious,etc.it is hard to identify minor fault in seismic interpretation.Thus,it's valuable and significant to study the seismic technique for identifying minor fault.Through investigating references home and abroad,this paper first introduces the research status of minor fault identification.Then according to the purpose of research as well as the early exploration achievement,this paper analyzes the seismic data and fault's characters,uses forward modeling method to certificate the existing of minor fault and its accuracy,chooses HFE(High Frequency Expanding),Structural-oriented filtering and seismic attributes to study farther more,finally applies them into real seismic data,which achieve good result.High Frequency Expanding is an effective method to improve resolution of seismic section.This method improves the resolution by back projecting the reflectance series from low frequency area to higher part and receiving a broader bandwidth data.So the minor fault can be identified better in seismic section.Structural-oriented filtering is an effective filtering method for post stack data,which use anisotropic diffusion filtering to seismic data to enhance the continuity of reflecting events and simultaneously keep the discontinuous information such as fault boundaries and lithology boundaries.Thus,it impresses minor fault more significantly in seismic section.In seismic attributes,coherence attribute and curvature attribute are two most susceptive methods to identify fault and minor fault.Therefore,in the last part,this paper introduces these attributes minutely.Based on seismic data,we extracts seismic attribute containing coherence attribute and curvature attribute.In result,it's better to identify minor fault.So,this method could be one of the most effective tools for identifying the minor fault.