海洋低信噪比单道地震资料特点及处理策略

    THE CHARACTERISTICS AND PROCESSING METHODS OFMARINE SINGLE-CHANNEL SEISMIC DATA WITH LOW SNR

    • 摘要: 海洋单道地震是海洋地球物理调查的常用手段之一,具有广阔的应用前景。但单道地震单一的覆盖次数及非等间距采集模式导致剖面信噪比低、多次波发育、垂向振幅能量差异大等特点。从单道地震的采集原理出发,阐述了单道地震资料处理中的3个难点:海底同相轴抖动、强振幅海底多次、严重背景随机噪音。针对涌浪引起的海底同相轴抖动问题,借用陆地资料静校正原理,将海底抖动分为高频和低频两个分量;采用互相关技术逐步消除高低频静校正分量。针对单道资料强振幅海底多次波,根据一维SRME算法原理,对单道数据运用一维SRME算法公式,预测的多次波模型与实际的多次波模型较为接近;针对单道资料低信噪比问题,将RNA去噪技术与LIFT去噪思想相结合,达到增强有效信号的同时压制空间随机干扰的目的。实际资料处理后的剖面信噪比与分辨率均显著提升,波组特征更加突出,成果资料满足用户解释需求。

       

      Abstract: Single-channel seismics, as a common method, is widely applied in marine geophysical survey. However, the method has some disadvantages, such as low signal-noise ratio, interference of multiple wave and large difference in vertical amplitude caused by single coverage and unequal acquisition intervals. Based on the acquisition principle of single-channel seismic survey, this paper is devoted to the three difficulties in processing single channel seismic data, i.e. seafloor in-phase axis jitter, seafloor multiple waves with strong amplitude, and serious background random noise. In order to solve the problem of seafloor in-phase axis jitter caused by surge wave, we subdivided the seafloor jitters into high frequency and low frequency components according to the principles we usually used for land data static correction. Cross-correlation technique is used to gradually eliminate the high and low frequency static correction components. For multiples, one-dimensional SRME algorithm formula is applied to single-channel data processing and make the predicted multiple wave model close to the actual. Concerning the problem of low SNR of single channel data, RNA technology combined with LIFT theory is adopted to enhance signals and suppress spatial random interferences. The SNR and resolution of the actual data after processing are significantly improved, and the wave group features become clearer.

       

    /

    返回文章
    返回