CMP道集反射波吸收方程和层Q值反演

基于弯曲射线和斯奈尔定理,导出了多层水平层状介质中CMP道集反射波的2个吸收方程,其中一个为炮检距的函数,另一个为旅行时的函数。将这2个方程与直射线近似吸收方程进行了精度对比。结果表明：基于曲射线与旅行时有关的吸收方程精度最高。基于这个高精度的吸收方程,发展了利用CMP道集反射波峰值频率反演层品质因子Q值的方法。该方法采用雷克子波描述地震子波和计算主频,利用多道记录计算平均衰减因子,利用层剥离方法计算层Q值。理论模型数据试算表明方法正确有效。

Absorption Equations and Interval Q Inversion of Reflection Waves from CMP Gather

Based on bending ray and Snell law, two absorption equations of reflection waves for Common Middle Point(CMP) gather in multi layer horizontal media were derived, one equation was the offset function, the other was the func-tion of travelling time. These two equations were compared with the approximate absorption equation derived under the assumption of straight ray. The results show that the equation on travelling time based on the bending ray has the higher precision than other equations. Based on this high accurate absorption equation, interval Q inversion method is developed by using the peak frequency of reflection waves from CMP records. Ricker wavelet is used to describe the seismic wavelet and calculate the peak frequency of reflection waves, multiple traces are used to calculate the average attenuation factors. Interval Q values are obtained by the layer stripping method. The validity is proved by theoretical model test.