Angle-stack reverse time migration in VTI media

Abstract

Seismic anisotropy is widespread in real media, the conventional isotropic reverse time migration method will lead to problems such as inaccurate depth and unfocused energy in dealing with the anisotropic issues, and low frequency noise with strong amplitude in imaging results can not be completely removed by simple filtering method such as Laplace filter operator. To solve these problems, we have researched pseudo acoustic equation to simulate qP wave propagation in anisotropic VTI media and used the smoothed isotropy or elliptic anisotropy tapered circular region located in source points to suppress the qSV wave. On this basis, we also develop angle-stack reverse time migration method in VTI media, which stacks the imaging results in angle domain to suppress low-frequency noise and improve imaging accuracy. Model test and application example prove that this method can obtain accurate imaging results with balanced energy in steep dip structures, and has better effect in suppressing low-frequency imaging noise.