Abstract:

The routinely picked results of first arrival of air-gun source data is poor, mainly because of its low signal-to-noise ratio (SNR). The anthors introduce the seismic exploration methods to pick the first-arrival and proposes a scheme for picking first-arrival in three stages to reduce the dependence on data’s SNR. Firstly, the noise was depressed. And then, the traditional exploration method was used to calculate the characteristic curve. Finally, the first-arrival was determined by combining the edge-preserving smoothing method. On this basis, according to the characteristics of practical data, the authors design an automatic pick-up process, which is used to pick up the first arrival of practical data. Compared with the traditional method, this method requires less SNR for the data and provides more available materials for subsequent processing and analysis.

Key words: air-gun source, wavelet transform, first arrival, fractal dimension

摘要：

针对气枪震源数据信噪比较低和自动拾取初至效果较差的问题, 通过引入地震勘探方法来进行初至震相拾取。首先压制噪声; 然后利用传统的勘探方法, 进行特征曲线计算; 最后结合保边平滑方法, 确定初至时间的三阶段方案, 降低自动拾取方法对数据信噪比要求。在此基础上, 根据实际数据特点, 设计自动拾取流程, 并用此流程对长江安徽段的主动源数据进行自动拾取。与传统方法相比, 所提方法对数据信噪比要求更低, 可为后续处理提供更多可用资料。

关键词: 气枪震源, 小波变换, 初至拾取, 分形维度