双相介质AVO方程及参数简化研究

基于2种双相介质分界面的反射系数和透射系数方程组，推导出了单相/双相分界面(储层顶界面)、双相/单相分界面(储层底界面)和单相/单相分界面(两种致密岩层分界面)3种类型分界面的反射系数和透射系数方程组，形成了从单相介质到双相介质较全面的AVO方程组；推导出了双相介质参数（A，N，Q，R，ρ11，ρ12，ρ22，）与纵波速度、横波速度、密度、孔隙度以及流体类型（油、气、水）之间的关系式，为双相介质AVO理论走向实用进行了有益的探索。设计了3种类型的岩性分界面，分别用双相介质AVO方程和Zeoppritz方程计算了各类界面的快纵波反射系数曲线，证实了Zoeppritz方程是双相介质AVO方程的一个特例。

A Study of AVO Equation in Dual-phase Medium and Parameter Simplification

Based on the equation group of reflection coefficient and transmission coefficient in the interface of two types of dual-phases mediums, three equation groups of reflection coefficient and transmission coefficient in three kinds of interfaces have been derived, which are the interface between one-phase and dual-phase medium that is the top of reservoir, dual-phase and one-phase that is the bottom of reservoir, one-phase and one-phase medium that is the interface of two tight rocks. The AVO equation group from one-phase to dual-phase has been produced comprehensively. The relationship formula have been built between parameters（A, N, Q, R, ρ₁₁, ρ₁₂, ρ₂₂, Ø） of the dual-phase medium and prime wave velocity, second wave velocity, density, porous and kind of fluid that include brine, oil and gas. All of these studies have made a beneficial exploration of AVO theory in dual-phase medium to practice. Three kinds of lithological interfaces have been designed. The reflection coefficient curves of different interfaces have been calculated respectively by dual-phase medium AVO equation and Zeoppritz equation, which provedhat Zeoppritz equation is a special case of dual-phase medium AVO equation.