张瑞, 黄建平, 李振春, 王炜, 袁双齐, 庄苏斌. 各向异性介质控制束偏移及海上数据应用实例[J]. 海洋地质与第四纪地质, 2020, 40(1): 184-197. DOI: 10.16562/j.cnki.0256-1492.2018120101
引用本文: 张瑞, 黄建平, 李振春, 王炜, 袁双齐, 庄苏斌. 各向异性介质控制束偏移及海上数据应用实例[J]. 海洋地质与第四纪地质, 2020, 40(1): 184-197. DOI: 10.16562/j.cnki.0256-1492.2018120101
ZHANG Rui, HUANG Jianping, LI Zhenchun, WANG Wei, YUAN Shuangqi, ZHUANG Subin. A controlled beam migration for anisotropic media and its application to marine data[J]. Marine Geology & Quaternary Geology, 2020, 40(1): 184-197. DOI: 10.16562/j.cnki.0256-1492.2018120101
Citation: ZHANG Rui, HUANG Jianping, LI Zhenchun, WANG Wei, YUAN Shuangqi, ZHUANG Subin. A controlled beam migration for anisotropic media and its application to marine data[J]. Marine Geology & Quaternary Geology, 2020, 40(1): 184-197. DOI: 10.16562/j.cnki.0256-1492.2018120101

各向异性介质控制束偏移及海上数据应用实例

A controlled beam migration for anisotropic media and its application to marine data

  • 摘要: 随着勘探区域逐渐从陆地过渡到海洋,勘探目标逐渐趋于复杂化,高精度成像方法已经成为海洋油气勘探的瓶颈技术。高斯束偏移是一种灵活且高效的深度域偏移方法,对实际资料成像具有较好的适应性。该文发展了一种适应于海洋观测系统的高精度高斯束偏移方法,首先将海上接收的共偏移距地震记录进行加窗局部倾斜叠加,通过数学变换将共炮域公式推广到共偏移距域,再从炮点和检波点分别进行射线追踪,最后采用数据驱动的方式进行成像。一方面,考虑到地下介质的各向异性,引入了各向异性射线追踪方程;另一方面,根据有效信号和干扰信号在τ-p域中的相干性差异,在高斯束偏移过程中对地震信号进行控制,降低偏移剖面中的随机噪声,提高同相轴的连续性,最终实现了一种VTI介质共偏移距域数据驱动控制束偏移理论方法。在实现算法的基础上,通过各向异性洼陷模型、修改的SEG/Hess VTI模型及海上实际资料成像试处理,结果表明:各向异性参数对共偏移距道集中的大偏移距信息成像质量改善明显;当地层各向异性不能忽略时,新方法能够更加准确地恢复地下的复杂构造;新方法能够在一定程度上提高低信噪比数据的偏移成像效果。

     

    Abstract: As exploration areas move from the land to the sea, research targets get more complicated, and the high-precision imaging method becomes critical for marine oil and gas exploration. Gaussian beam migration (GBM) is a robust imaging method with high computational efficiency and flexibility. A high-precision GBM method, suitable for marine observation systems, has been developed by the authors in this paper, which contains the transformation between common-shot and common-offset domains and the data-driven framework. On one hand, considering the anisotropy of the subsurface media, an anisotropic ray tracing equation is introduced. On the other hand, based on the semblance difference between signal and disturbance in the τ-p domain, we develop the semblance threshold filtering method to eliminate disturbance during GBM procedure, thereby reducing migration noise. Numerical tests on anisotropic sag model, modified SEG/Hess VTI model and marine data suggest that (1) anisotropic parameters can improve the imaging quality significantly for the large offset data, (2) the proposed method can more accurately recover the complex structure, and (3) the new method may improve the signal-to-noise ratio (S/N) of the migration profile to a certain extent.

     

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