波场分离互相关成像条件的叠前逆时偏移  

Reverse Time Migration for Wavefield Separation Cross-correlation Imaging Conditions

作　　者：唐文[1] 高秦 赖生华[1] 

机构地区：[1]西安石油大学地球科学与工程学院,陕西西安710065 [2]东方地球物理勘探有限责任公司研究院长庆分院,陕西西安710021

出　　处：《石油天然气学报》2014年第10期59-64,5-6,共6页Journal of Oil and Gas Technology

基　　金：国家自然科学基金项目(41372118);陕西省教育厅专项科研计划项目(2013JK0845);西安市科技计划项目(CXY1346(6))

摘　　要：对于陡倾角构造和复杂速度模型的成像,逆时偏移被认为是目前最好的偏移成像技术。然而,传统的互相关成像条件产生的低频率、强振幅的噪声严重地影响了有效信号的识别。为此,通过实现基于有限元法的声波方程的叠前逆时偏移,加载了完全匹配层吸收边界,压制了边界反射能量;并通过分析逆时偏移剖面低频噪声产的生原因,把震源波场和接收波场分离为单程波,然后对分解的波场选用有效分量进行互相关成像,以达到压制成像噪声的目的。通过数值模拟,并应用有效的波场成分进行互成像条件的处理,验证了该方法对压制成像剖面中的低频率、强振幅噪声的有效性。Reverse time migration(RTM)was regarded as the best migration method to handle steeply dipping structures and complicated velocity models.However,the conventional cross-correlated imaging condition produced low-frequency and high-amplitude noises in the image,which would seriously contaminate the signals in the image.Wavefield separation cross-correlation imaging conditions were proposed to eliminate these specific noises from the image.The method was used for decomposing both the source and receiver wavefields to their one-way propagation components,cross-correlation imaging conditions were chosen by using effective components of the decomposed wavefields.The physical explanation of the principle of such noises in the conventional RTM image is given firstly,then the detailed mathematical theory for the new imaging condition is provided.An efficient scheme for its numerical implementation is proposed.Applications to various synthetic datasets verify that the wavefield separation cross-correlation imaging conditions can effectively remove the undesired noises in the image.

关 键 词：噪声 波场分离 互相关成像条件 逆时偏移 

分 类 号：P631.44[天文地球—地质矿产勘探]