多波AVA及岩性预测

Multiwave AVA and lithology prediction

针对多波摄幅信息的研究及应用，本文介绍一套较高精度的AVA正演模拟方法、多波振幅特征处理方法及多波AVA曲线直接预测岩性界面的方法。文中通过其例，说明AVA近似正演不仅适用于P、SV、SH波源，而且模拟精度高，可在入射角为65°范围内达精确解。多波振幅特征处理包括AVO道集形成及AVO到AVA的转换、AVA曲线拟会及属性剖面的产生。对非转换波可输出零炮检距剖面及属性创面，能有效地提高多波剖面的分辨率，增强剖面中的纵横向变化特征。此外，本文根据多波AVA曲线变化规律与岩性界面的依赖关系，提出在多波AVA曲线上通过人工神经网络直接预测岩性界面的方法，从而大大地提高了多波多分量地震资料的应用价值。

Some accurate methods relating to AVA forward modeling,multiwave ampli-tude characteristic processing and direct lithologic interface prediction using multi-wave AVA curve are advanced in order to do good research and application of multi-wave amplitude informations.Trial computation shows that approximate AVA forward modeling is very ap-plicable to P,SV and SH-waves,and brings accurate results even when incident an-gle is 65 degrees. The multiwave amplitude characteristic processing includes AVO trace gathering, AVo-AVA conversion, AVA curve fitting and attributive section output. Zero-offset and attributive sections of non-converted multiwaves can also be produced,which have better resolution and show obvious varied characteristics. In addition,on the basis of the relation between an AVA curve and lithology interface,we develop a new method for dlrect predicting lithology interface by applying neural network to multiwave AVA curve,so that the applicability of multiwave and multi-component seismic data is raised greatly.