多方向正交多项式变换压制多次波

提出一种基于Radon 变换和正交多项式变换的多方向正交多项式变换压制多次波方法.抛物Radon变换对不同曲率方向的同相轴叠加,根据速度差异区分一次波和多次波,但Radon反变换会损伤振幅特性,不利于AVO分析.多方向正交多项式变换在Radon变换(某一曲率方向的零阶特性)的基础上,利用正交多项式变换进一步分析同相轴的高阶多项式分布特性,用正交多项式谱表征同相轴AVO特性;根据一次波和多次波速度差异和同相轴能量分布特征实现多次波压制.该方法的优点是仅用一个曲率参数就可描述同相轴剩余时差参数,提高了一次波和多次波的剩余时差分辨率.实验结果表明,该方法可以有效压制多次波并保留一次波AVO特性.

Multiples attenuation based on directional orthogonal polynomial transform

A demultiple method is proposed based on Radon and orthogonal polynomial transform. Parabolic Radon transform attenuates the multiples based on the different moveout of primaries and multiples, but can't keep the amplitude versus offset (AVO) of event because its operator is not orthogonal, especially for the near-offset amplitude. Compared with the zero-order AVO property of Radon transform, the directional orthogonal polynomial transform analyzes not only the zero-order but other high order polynomial properties of AVO which can represent AVO completely. This method takes advantage of Radon transform and orthogonal polynomial transform and can distinguish different event with their moveout and keep the event amplitude with their orthogonal polynomial coefficients. According to the energy distribution of events in the τ－q domain, the events q parameters are picked up and multiples can be attenuated. This method represents AVO with only one curvature parameter and improves the resolution of primaries and multiples. The processing of synthetic and real data shows good performance in multiples attenuation and keeping AVO properties.