道间距对地震偏移的影响

道间距的变化对地震数据的偏移效果是有影响的。首先,道间距的大小必须满足空间采样定律,否则将会产生假频,而且这些假频信号会带到偏移过程中从而影响成像的质量;其次,采用近似差分算子或条件稳定差分格式的有限差分偏移算法对道间距有一定的要求,否则迭代计算过程将不收敛,产生频散现象;而对于其它格式的差分法偏移和积分法偏移,道间距越小,越有利于成像效果的提高。除上述数值解稳定性、假频和频散问题外,高密度采集对偏移效果生产的影响主要体现在信噪比和视觉分辨率的提高。

Effect of group interval on seismic migration

The change of group interval will affect the migration of seismic data.Firstly,the length of group interval shall meet the spatial sampling law,provided otherwise,the aliasing will arise.Furthermore,the aliasing signals will affect the imaging quality in the process of migration.Secondly,the fi-nite difference migration algorithm of the approximate differ-ence operator or the conditional stability difference scheme shall be adopted in certain conditions,provided otherwise,the iterative computation will not be convergent with the dis-persion.However,for the difference migration and integra-tion migration of other formats,the less the group interval,the better the imaging quality.Except the above stability of numerical solution,the aliasing and the dispersion,the effect of high-density acquisition on migration appear in the in-creases in signal-to-noise ratio and visual resolution.