三维倾斜界面PS转换波CMP道集时距及参数估计

在PS转换波资料处理过程中,往往需要联合P波资料提供相应的模型.在实际应用中存在P波和PS转换波层位对比困难.本文仅利用PS转换波数据,通过三维倾斜界面PS转换波CMP道集精确时距关系推导了近似时距解析表达式;分析了PS波的精确与近似时距关系随测线方位、界面倾角与倾向的变化规律及其拟合误差;并讨论了近似时距关系的三个时距参数随方位的变化特征;理论上给出描述时距的三维倾斜界面倾角、倾向、深度、纵波速度和横波速度这5个独立参数的估计方法,并通过理论模拟数据证明了该方法的可行性.

Moveout and parameter estimation of converted waves at CMP gathers from 3D dipping interface

In the processing of converted wave data,P-wave data is often needed to be jointed to provide the corresponding model.In the practical application,there is a difficulty in confirming P-wave and PS-wave from the same reflector.In this article PS-wave data is only used and the approximated moveout analytical expressions of PS-waves are derived at the CMP gathers for the three-dimensional dipping interface.The properties and fitness error are discussed about exact and approximate PS moveout which change with survey azimuths,dipping angles and dip orientations.Furthermore,a theoretical parameter estimation method is also given.The five parameters which are dip angle,dip orientation,depth,P-wave velocity and S-wave velocity are used to describe the relation of travel time and distance.An example from a synthetic model is used to show that this parameter estimation method is feasible.