利用改进的扩展多道匹配相减法压制多次波

Suppression of multiples by improved expanding multi-channel match minus method.

本文采用基于时差方程的多次波预测方法预测多次波模型记录,结合单道匹配、常规多道匹配、伪多道匹配和扩展多道匹配四种相减方法的优缺点,给出了改进的多道匹配相减方法和改进的扩展多道匹配相减方法的计算步骤,并尝试在匹配相减方法中评估迭代思想的作用。通过理论模型和实测资料的测试,得出了以下主要结论:①在已知水层深度这一先验信息的前提下,利用时差方程方法预测多次波模型记录,计算速度快,精度基本满足要求,是一种预测海底多次波的有效方法;②改进的扩展多道匹配相减方法适应能力较强,具有较好的信号保真度,在模型测试和实际数据应用中,均取得了较为满意的效果,并可与其他预测方法搭配使用;③滤波因子长度、时窗大小和相邻匹配道数这三个主要控制参数,对匹配相减的效果有影响,在应用匹配相减方法时,需要针对数据本身的特点,选择合适的匹配参数。经过对比迭代匹配相减的结果发现,迭代运算对于提高匹配精度的作用不大。

Using multiple prediction method for predicting multiple model records based on moveout equation and in combination with the advantages and disadvantages of four minus methods: single-channel match, conventional multi-channel match, pseudo-multi-channel match and expanding multi-channel match, the paper presented improved ideas, gave computational steps of improved multi-channel match minus method and improved expanding multi-channel match minus methods and tried to evaluate the role of iterative idea in match minus method. It got following main conclusions by theoretical model and practical test data: in a precondition of known a prior-information of water layer depth, using moveout equation method to predice multiple model records is characterized by fast computational speed and basically meeting the requirement of precision, which is an effective method predicting sea-bottom multiples; the improved expanding multi-channel match minus method is characterized by strong adaptive capacity and good hi-fi of signal, acquiring satisfactory effect in model test and practical data application, which can joint application with other predicting methods; the three main controlling factors: length and window size of filtering factor and number of adjacent match channels have influence on effect of match minus method, which should select appropriate match parameters according to the feature of data themselves when using match minus method. It discovered by correlation of iterative match minus results that iterative operation plays any role in improving the match precision.