地震共偏移距数据集的空间分辨率分析

Analysis on the spatial resolution in common offset gather of seismic data

地震采集观测系统直接影响所获地震资料的信噪比与分辨率。从已有的理论公式出发,分别导出了二维、三维共偏移距道集的空间分辨率公式,较系统地讨论了共偏移距道集的横向分辨率和垂向分辨率与地下介质速度、地震主频及频带、反射界面倾角、偏移孔径以及所使用的观测系统等因素的关系。研究分析表明:较大的观测孔径有利于横向分辨率的提高;倾角或偏移孔径越大,横向分辨率越高,垂向分辨率却越低;非零偏移距数据体的空间分辨率比零偏移距有所降低;采集的方位角对x方向和y方向的分辨率也有影响。所取得的成果与认识可望为地震采集观测系统的设计提供理论指导。

Seismic acquisition geometry directly affects the S/N and the resolution of seismic data.From the existing theoretical formulas, the spatial resolution formula in 2Dand 3Dcommon offset gather is derived,and the relationship between the possible horizontal and vertical resolution of common offset gathers with the factors such as subsurface velocity,maximum frequency,migration aperture,as well as geometry are systematically discussed.It is concluded that larger aperture observations help the improvement of lateral resolution;the greater dip angle or migration aperture,the higher lateral resolution and the lower vertical resolution;spatial resolution of non-zero offset gather is lower than that of zero offset;acquisition azimuth affects both of the resolutions in X and Y directions.It will provide theoretical guidance to survey design.