速度、零偏移距剖面和DMO处理

Velocity, zero-offset section and DMO

地矿部石油物探研究所, 南京210014

Research Institute of Geophysical Prospccting for Pctrolcum, MGMR．Nanjing City, Intcranl Postcodc 210014

本文在回顾几种目前流行的DMO处理的基础上, 论证了使用常规计算方法在常规CMP道集上就能实现对DMO处理的各项要求, 其中包括倾斜界面条件下均方根速度近似值的确定和零偏移距剖面的构组。此外, 本文还深入分析了CMP道集的时间方程, 提出使用径向CMP道集数据计算均方根速度的近似值和地层倾角；使用横向CMP道集数据以一次动校求取零偏移距剖面, 二次动校求取均方根速度近似值。模拟数据计算证明, 这些方法的误差很小。

Based on a review on several techniques in common use for DMO processing, this paper demonstrates that conventional algorithms performed on conventional CMP data can meet the requirements of DMO processing, including the determination of root-mcan-square velocities in case of inclined interface and the construction for zcro-offeet sections. In addition, after analyzing the time equation of a CMP gather, this paper suggests (1) calculating root-meam-square velocities and dips by use of radical CMP gather data and (2) constructing zero-offset sections via the primary NMO correction performed on in-Iine CMP gathers and dcriving velocities via a subsequent NMO correction on the constructed zero-offset sections. Modeling data experiments show that the errors of these methods are acccptable.