基于Zoeppritz方程的纵横波模量反演

Compressional and shear modulus inversion based on Zoeppritz equation

叠前地震反演的主要目的是根据地震数据精确地求取地下介质的弹性参数,进而进行流体识别和油藏描述。常规叠前反演方法使用Zoeppritz方程近似式计算反射系数,但是含有丰富信息的大偏移距地震数据无法被有效利用,针对这个问题,将纵横波模量引入Zoeppritz方程,建立了基于Zoeppritz方程的纵横波模量广义线性反演方法,适用于大角度地震数据。模型测试和实际地震资料应用表明,此方法能够可靠的得到地下介质的纵横波模量,相对于间接反演减小了间接反演带来的累积误差,为后续流体识别和含油气检测提供了很好的数据基础。

The main purpose of pre-stack seismic inversion lies in getting elastic parameters of underground media and then making liquid identification and reservoir description.In this paper the authors tried to eliminate the inherent trouble that long offset seismic data could not be used efficiently when the approximate Zoeppritz equation is adopted. The authors start with the Zoeppritz equation of P-wave and S-wave velocity and obtain the Zoeppritz equation of compressional and shear modulus.Then,with the new Zoeppritz equation,the authors start the direct compressional and shear modulus inversion based on the generalized linear inversion theory and apply the means to seismic data with all angles.Model and practical test shows that the method is stable and reasonable in obtaining the compressional and shear modulus,and can reduce the cumulative error which is caused by the common elastic inversion method.The result obtained by the authors provides good data basis for the liquid detection and identification.