Forward Modeling Of Seismic Ray Tracing And Its Application

Research on the seismic waves's propagation plays an important role in geophysics exploration. Until now the seismic ray method has been used in many aspects of the seismic prospecting. For example, the method is used to calculate the seismic wavefield in 3D isotropic and anisotropic medium. Seismic ray method can also solve some complicated forward and inversion problems of transverse anisotropy medium in the field of seismology and exploration activity. Dynamic ray tracing is one of the most important methods in existent ray methods. The most important application of dynamic ray tracing is to calculate paraxial ray and Gaussian beam.Ray tracing is a rapid and effective method in wavefield calculation. Not only in the field of seismic-wave theory, but also in the field of the seismic inversion and imaging, seismic ray tracing method has become the most important method.Firstly this paper introduces the basic seismic ray tracing theory. Then forward modeling of seismic ray tracing is done by SEIS package. Under the premise of knowing the complicated medium under the ground, we build the velocity model in depth domain and obtain seismogram, ray diagram, travel time curve and amplitude diagram.Compensation function g(t) is achieved by analyzing the result of seismogram. Then g(t) is used to correct the amplitude in any trace. We analyzes how to get the function g(t) during both RMS Amplitude AGC and Instantaneous AGC process in this paper. The result shows window length and the value of threshold have a great impact on the effectiveness of compensation.On the basis of our understanding on the compensation function and the ray tracing theory, compensation method was used to process the real data in the South China Sea and achieved satisfactory results.