一种改进的射线弹性阻抗公式及弹性参数反演

One modified ray-path elastic impedance and elastic parameter inversion

(1.成都理工大学地球物理学院,四川成都610059;2.北京诺克斯达石油科技有限公司,北京100192)

Liu Lihui, Chengdu University of Technology,Chengdu 610059,China

用射线弹性阻抗直接求解纵横波速度比时,解析式是由两个弹性阻抗比值构成的高幂次函数,在实际应用时，其稳定性和抗噪能力较差,因而其应用前景受到制约。在生产中有必要开发出一种改进的射线弹性阻抗,使弹性参数求解更加稳定。对射线弹性阻抗公式进行二次项展开,将射线弹性阻抗表达成纵波阻抗和横波阻抗的函数。通过误差推导和实验分析,给出了用其反演纵波阻抗、横波阻抗及其它弹性参数的解析式。最后在某海上油田工区应用该方法进行反演,取得了良好的应用效果。

During the direct computation of vP/vS by ray-path elastic impedance,the analytic expression is high-power function consisted of the ratio of two elastic impedance,which has poor stability and anti-noise ability,so it is limited for application.Therefore,one modified ray-path elastic impedance need to be developed to make the computation of elastic parameters more stable.Through using binomial theorem quadratic to the ray-path elastic impedance formula,the ray-path elastic impedance was expressed into a function of P-wave impedance and S-wave impedance.By experimental analysis and error derivation,analytical formula of P-wave impendence,S-wave impendence and other elastic parameters were given.The application in some offshore area obtained good results.

10.3969/j.issn.1000-1441.2011.04.003