砂泥岩薄互层分辨率的理论分析

Theoretic analysis of the resolution of thin sand-mud interbed

东方地球物理公司研究院,河北涿州 072750

Geophysical Research Institute, Bureau of Geophysical Prospecting, Zhuozhou 072750, China

由于原始地震数据频带的限制,难以直接从地震剖面上分辨10 m以下的薄层。在薄互层发育的地区,地震分辨率受多种因素的影响。为此,从理论模型出发,分析了子波的类型、频带宽度以及视频率对地震分辨率的影响,并根据东部YTD地区测井数据,计算地震视频率与可分辨厚度之间的关系。通过叠前和叠后井旁地震道的分析,说明了实际数据频带分布限制了薄互层分辨率,给出了在资料处理中针对提高分辨率这一问题应采取的措施。本研究的目的是使处理人员认识薄互层的地震响应及变化规律,以便采用适当的手段最佳地体现薄互层的反射特征,为薄互层的资料解释提供依据。

It is difficult to identify thin layers less than 10m in thickness because of the limitation of seismicfrequency band. Seismic resolution is affected bymany factors such as the type of wavelet, the seismicfrequency band, the apparent frequency of field data,etc. Their relationship is analyzed on theoreticalmodels. The relation between seismic apparent fre-quency and resolvable thickness is studied on welllogging data from YTD area. Some measures for en-hancing seismic resolution is concluded from an anal-ysis of limits of frequency band on the resolvability ofthin interbed on prestack and poststack data. The re-sults are helpful for processors to adopt proper pro-cessing methods.