含气储层及盖层速度变化对地震响应和AVO 类型的影响

莺歌海盆地在近年来的勘探中钻遇了异于常规地震响应特征的气层，通过研究含气储层及盖层纵 波速度的变化，分析了含气储层新型地震响应特征产生的原因。 相对于常规“两红夹一黑”含气储层地震 响应特征，“上黑下红”及“上红下黑”新型含气储层地震响应特征丰富了该盆地气藏组合地震响应特征， 为下一步寻找有利目标拓宽了思路。 另外，测井岩石物理分析发现，储层相对于盖层不同的纵波速度及 横波速度其曲线形态与储层顶界 AVO 类型存在着一定的对应关系。 在叠前 AVO 研究中可直接根据纵 波速度、横波速度及波阻抗的曲线形态大致判断储层的 AVO 类型。

Influence of velocity changing of gas reservoir and seal on seismic response and AVO type

Some gas layers with abnormal seismic response characteristics were found in recent years in the Yinggehai Basin. By means of studying the P-wave velocity changing of gas reservoir and seal, the reasons of the new type of seismic response characteristics formed in gas reservoir were analyzed. Compared with the normal seismic response characteristic of “two red with one black” of gas reservoir, the new type of seismic response characteristics of “upper black down red” and “upper red down black” made the seismic response type of gas reservoir richer, which broadens the thought for finding the potential target. In addition, the study of logging rock physics shows that the P-wave and S-wave velocity changing of seal may have the relationship with the AVO type of gas reservoir, and different P-wave and S-wave velocity curve shape corresponds to different AVO type. So we can roughly distinguish the AVO type according to the P-wave velocity, S-wave velocity and P-wave impedance curve shape in the prestack AVO study.