薄层响应对反射波的影响

目前,一般油气地衷勘探中的子波频宽小于两个倍频程,其延续长度及子波旁辫的振幅都很大。对于薄互层而言,子波的延续长度及子波旁辫对反射波 的影响是不容忽视的。薄互层组合的反射波振幅既是岩性的函数,又是薄层组合(层数和厚度)的函数。薄互层反封的振幅与岩性的关系是一种复杂多变的关系。J15井浅层气藏是这种复杂关系的典型例子。应充分估计到薄层组合响应的影响,进免将通常厚层反射的概念不加分析地硬套在薄层反射上造成解释的错误。运用浏井资料进行地襄正反演,把握薄层响应对地震反射波的影晚是避免堕入地襄“陷阱”的有效方法。

The influence of thin-bed response an reflection

Generally speaking, the frequency band of wavelets in present oil-gas seismic exploration is less than two octaves; and the wavelets have both long durations and big side-lobe amplitudes. As for thin-bed series, the influence of the durations and side lobes on reflections is nonnegligible. The amplitude of reflection from thin-bed series is a function of lithology,bed number and bed thickness. The relation between the amplitude of thin-bed series reflection and lithology is complicated and varying. The shallow gas reservoir at well Jl5 is a typical example showing this complex relation. The influence of thin-bed-series response should be sufficiently considered so as to avoid the interpretation mistakes caused because of misusing the thick-bed reflection concept in the interpretation of thin-bed-serifs reflections. To ascertain the influence of thin-bed-series response on seimic reflection by making forward and inverse seismic modeling using log data is an effective method for avoiding "seismic pitfall".