交互减去法压制多次波技术——以北部湾盆地福山凹陷为例

Technique of interactive subtraction multiple elimination:A case of Fushan Sag in Beibuwan Basin

北部湾盆地福山凹陷火成岩分布广泛,与浅表层围岩形成很强的纵波和横波波阻抗界面,对有效地震波的下传与上返形成了很强的屏蔽,致使来自深部的反射信息能量大幅衰减,严重影响了该区地震资料品质,因此火成岩多次波干扰是该地区地震资料处理所面临的首要难题。通过分析研究火成岩分布特征、火成岩与多次波之间的关系,在波动方程模型正演理论指导下,探索压制多次波干扰的处理技术与方法,提出了对近炮检距多次波压制、对远炮检距多次波不予压制的交互减去法压制多次波技术并将这一技术应用到实际地震资料处理中,取得了很好的应用效果,既对多次波给予了有效压制,又使一次波、断面波等有用信号得到保护并最终成像,同时地震资料的品质大大改善。

Volcanic rocks are widely developed in the Fushan Sag in Beibuwan Basin,and they create strong impedance interfaces with the shallow surrounding rocks,forming shields for seismic signals thus causing the attenuation of reflection energy at depth and affecting the quality of seismic data badly.So,multiples with volcanic are the prime problem of the seismic data processing in the area.By studying the developing features of the volcanics and the relationships between the volcanics and the multiples,and using the theories of the wave equations,we provide the technique of interactive subtraction multiple elimination.The feature of this technique is to eliminate the near offset multiples,and not to eliminate far offset multiples,which are eliminated by multiple stacking.The interactive subtraction multiple elimination technique has been used to process seismic data.Results show that it can eliminate multiples,protect useful signals and image,as well as improve the seismic data quality.