初至波能量比迭代拾取方法

Iteration pickup method of first break using energy ratio

本文提出了一种创新的初至波自动拾取方法,免人工干扰,抗干扰能力强,自动剔除低信噪比道,利用二次拾取保证初至拾取结果的可靠性和提高拾取道数.该方法首先利用空间多时窗内插方法,确定每道时窗位置,基于数字图像处理技术,计算初至时窗内地震数据每个采样点的能量比值,结合初至波波形和能量的特点确定初至时间的位置;然后利用相邻初至波相互约束对拾取的初至波进行评价,确定可信度低的初至波;最后利用可信度高的初至波作为约束条件对可信度低和未拾取的初至波二次拾取,二次拾取过程中利用能量、频率、波形等对初至波进行判断,剔除掉异常干扰道.本方法利用新的能量比值法在一定程度上能消除初至波到达前的随机干扰,初至评价和二次拾取有效地识别和剔除干扰道,提高二次拾取质量,减少手工交互的工作量,满足了地震勘探中对初至波拾取的要求.经过实际数据的应用表明,此算法对于初至波形变化较大、背景噪声干扰严重等的低信噪比资料,自动拾取初至的效率和精度都得到了预期的效果.

In this paper first-break is auto-picked using some advanced and creative algorithms,Auto-picking is totally free from intervention and strong anti-interference ability,for the low SNR race the FB time is set to zero,improved reliable first break and trace numbers make use of second pick up.. Firstly,the method use spacetime window interpolation technology to determine the position of each time window. based on digital image processing,calculateing every sample point energy ratio,and determines first break position on energy and waveform characteristic. Secondly,we evaluate low reliability first break to make use of adjacent first break to mutual restraint. Finally,we use reliable first break to second pick up low reliability coefficients and not picked up,considering the first break energy、frequency and waveform to Eliminate abnormal traces. the method make use of new ratio of energy to elimination of random interference before arrival of the first break,evaluation and second pick up effectively identify and eliminate interference traces,Improvd the quality of second pick up,reduce the workload of manual interaction,and meet the requirements of first pick in the seismic exploration. The method has been demonstrated by actual seismic data, for first arrival waveform change greatly,all kinds of wave interference,background noise serious low signal to noise ratio seismic data, it has obviously improved the computational precision and efficiency than the existing pickup methods,we get the expected results.