极浅水环境下的水层多次波分阶压制

Multi Order Attenuation of Water Layer in Very Shallow Water Environment

SRME(Surface Related Multiple Elimination)方法无法在浅水环境下实现地震资料水层多次波的准确预测。目前浅水多次波预测通常使用基于格林函数的多次波预测方法,但该方法在极浅水环境下时,浅层应用效果较好,深层效果较差。主要因为极浅水环境下水层多次波周期较短,地震波主频随传播降低,深层一次波与水层多次波混叠,使用自适应减法时,会造成有效波损失。因此,本文提出一种在极浅水环境下改进的格林函数多次波预测方法,首先通过对深层进行二阶及以上多次波预测,再利用自适应减法优化水层多次波的预测和衰减。通过模拟数据和实际数据测试,结果表明,该方法可以在避免有效波损失的前提下,较好地衰减水层多次波。本文提出的方法可配合预测反褶积等手段应用于浅水多次波压制,进一步提高多次波预测精度和压制效果。

Because SRME(surface related multiple elimination)method can not accurately predict the seabed multiples in shallow water environment,the Green function based multiples prediction method is usually used to predict the seabed multiples.This method works better in shallow water environment,but not ideally in deep layer,mainly because the main frequency of seismic wave decreases with the propagation,and the seabed multiples period is short in very shallow water environment.When the adaptive subtraction is used,the effective wave loss occurs.In this paper,an improved Green function multiple prediction method in extremely shallow water environment is proposed.The second order and above multiples wave prediction is first carried out in deep layer.Then,the adaptive subtraction method is used to subtract the multiple wave model from the original data to complete the prediction and attenuation of multiple waves.Through the simulation data and the actual data test,the seabed multiples can be attenuated better under the premise of avoiding the effective wave loss.This method can be applied to shallow water multiple suppression in combination with deconvolution method,so as to further improve the prediction accuracy and suppression effect of multiple.