共散射点道集映射噪声压制方法及其应用

Mapping noise suppression in common scattering point gathers and its application.

中国石油大学(华东)地球科学与技术学院，山东青岛266580

Song Xiangyu, School of Geosciences,China University of Petroleum (East China),Qingdao 266580,China

引入等价偏移距后，可将叠前双平方根旅行时方程改写成单平方根旅行时方程。利用单平方根旅行时方程构建的共散射点(Common Scatter Point,CSP)道集具有提高覆盖次数以及空间反假频等优点;利用它进行速度分析，叠加CSP道集后可以直接得到叠前时间偏移剖面。但在生成CSP道集的过程中存在映射噪声，映射噪声的存在会降低速度拾取的精度，并影响成像效果。在分析CSP道集映射过程中噪声产生机制的基础上，提出了引入振幅校正因子对其进行压制的方法。模型数据和实际资料的试算结果表明，经过噪声压制后的CSP道集和速度谱都有明显的改进，成像质量也得到明显提高。

By introducing equivalent offset,we can obtain the single square root traveltime equation from the double square root traveltime equation.Commonscatterpoint (CSP) gathers constructed from the single square root traveltime equation has the advantages of increasing the number of coverage and spatial antialiasing.Using it for velocity analysis,prestack time migration profile can be obtained after stacking CSP gathers.But there are mapping noise during generating CSP gathers.Mapping noise may reduce the accuracy of picking velocity and impact the quality of migration.On the basis of studying the generation mechanism of the mapping noise,amplitude correction factor is introduced to suppress the noise.The tests on model and real data indicates that the CSP gather and NMO spectrum is improved greatly after noise suppression,and the quality of migration is also improved obviously.

国家自然科学基金(41204086)、中国石油大学自主创新科研计划资助项目(13CX02041A)、教育部博士点基金项目(20110133120001)、国家高技术研究发展计划(863)课题(2011AA060301)和国家科技重大专项(2011ZX05006002)联合资助。

10.3969/j.issn.10001441.2013.05.012