The AVO Forward Modeling And Application Research Of Shallow Seismic

AVO is the Amplitude Variation with Offset,or the Amplitude versus offset.AVO technology is a kind of method to detect the petrophysical parameter of rock with the relationship between seismic wave amplitude and offset(Angle),it has been widely used in exploration for oil and natural gas,coal and other resources and achieved good results.But in the field of engineering investigation,the AVO technique is not a common application,its theoretical research is relatively less at present.Therefore, it is a great significance.to establish the corresponding geological and geophysical model, to conduct the AVO forward modeling,and analysis,sum up the lawsOn the basis of predecessors' research,the paper deduced the Zoeppritz equation and boundary conditions which is based on plane wave,and deduced the Zoeppritz equation which is based on arc spherical wave,then the paper analyzed the difference between plan wave AVO and spherical wave AVO of the shallow seismic reflection wave.The mathematical physical model which are Horizontal layered single interface model,underground cavity model,the local rich water model and so on are established,using the wave equation,aim at the relationship between reflected wave amplitude and the Angle of incidence to forward modeling and the curve plotting with Tesseral and Matlab programming,with grid subdivision and increased cell(Mesh) to improve the simulation accuracy,increase the reliability of the forward modeling.By comparing and analyzing the results from the observed seismic data and forward modeling to be seen,under the condition of plane wave incidence and the single interface,seismic reflection wave amplitude gradually reduce with the increase of incident Angle,it is to say that the seismic wave energy is fading in a certain distance;When the seismic waves meet with carve in the course of transmission to the underground,the polarity of seismic waves do not change, but the amplitude of reflected wave has the trend that from strong to weak with the increase of incident Angle;When the seismic waves meet with water in the course of transmission to the underground,the amplitude of reflection waves decreases first and then increased gradually;Under the condition of spherical wave incidence, seismic AVO is not only related to the wave impedance but also associated with the depth of elastic interface,the deeper of the depth the more close to the plane wave AVO.The AVO forward modeling of shallow seismic wave is the basis of shallow seismic exploration data processing and inversion interpretation,it can offer AVO technology application in the engineering survey method.