单程波角度域内压制多次波偏移假象

多次波偏移中的假象主要来自于不同地震事件之间的互相关,由于这种互相关满足成像条件,很难直接在偏移过程中去除.但是对于准确的速度模型,真实的成像结果在角度域内应该是平直的.根据这个判断准则,可以在角度域内移除多次波偏移中的假象.本文以数据自相关偏移为例,提出了在单程波多次波偏移中移除假象的主要流程:首先在在单程波偏移过程中高效地提取角度域共成像点道集,然后对角度域共成像点道集应用高分辨率的抛物线型Radon变换,用合适的切除函数处理后,反变换回到角度域,最后叠加各个角度成分,得到偏移结果.Marmousi模型的合成数据测试表明,这种方法可以很好地压制多次波偏移过程中产生的假象,有效地提高成像结果的信噪比.

地震干涉处理方法在随钻地震资料处理中的应用

本文在简明阐述地震干涉理论及相关算法的基础上,结合随钻地震数据处理的特点,开展了地震干涉处理和偏移成像方法的研究。通过对胜利油田Fan158井随钻地震数据进行频率波数域滤波、干涉和垂直叠加处理,从强噪声背景下提取了钻头激发的有效信号,并对该数据进行了Kirchhoff和自相关偏移成像处理。再结合工区地面地震资料,对剖面的波组特征进行了分析,结果表明,应用反褶积干涉处理和自相关偏移成像均取得较好效果。

Parameters effects on spiking deconvolution of land seismic data

Spiking deconvolution is a standard Wiener Levinson algorithm. The autocorrelation of the design time gate is computed and there is a specified taper on the design gate before the autoeorrelation is done. The standard equations are set up, prewhitening is added to the zero lag value of the autocorrelation and the matrix is inverted to derive the spiking operator. In this study, the authors describe a technique for performing spiking deconvolution on prestack time migration （PSTM） data, to test the effect of operator length and percent prewhitening in spiking deconvolution and apply spiking deconvolution trace by trace, with operator lengths 15ms, 10 ms and 5 ms when percent prewhitening 0% , 40ms and 60ms for percent prewhitening 1%. The results show when prewhitening is 0% the shorter operator gives better results, but when value of prewhitening is bigger than 0% it is better to use longer operator lengths.