Study on the Rational Function Characterization of Wide-Angle AVO

The plane-wave approximate wave field propagation can produce large error in the wide incidence angles, and is only applicable to small incidence angles, while the spherical-wave theory is more accurate to describe the real wave propagation. The convention polynomial AVO representation is only for small incident angles, so a new rational function fitting method for wide-angle seismic data is proposed in this paper. We first use the AVO reflection characteristics of spherical-wave to simulate the spherical-wave AVO forward model. According to the theory that the reflection coefficient conforms to the characteristic of rational function, it is proposed to fit and reconstruct the seismic data by using rational function fitting, especially in wide-angle. According to the properties of rational function, the AVO is classified by the zero-pole attributes. We get the conclusion that using the rational function fitting, the research range can expand to the large offsets, the zeros and residue attributes obtained by the rational function fitting can characterize AVO attributes and classify AVO types more accurately.