双相介质中储层波场特征数值模拟研究

根据双相介质弹性波方程，并对弹性波方程进行分离得到了膨胀波方程。利用高阶差分对膨胀波方程进行数值模拟，边界处理采用完全匹配层的吸收边界条件，算法实现了任意高阶差分和自动加载边界条件的纵波方程正演模拟。计算结果表明，在双相各向同性介质中存在快纵波、慢纵波，两种纵波有明显的区别，快纵波的速度远大于慢纵波的速度。在分界面上，快纵波要产生透射快纵波、透射转换慢纵波，反射快纵波、反射转换慢纵波。慢纵波具有很强的衰减性，耗散系数越小，慢纵波越明显，反之亦然。该算法的高阶差分形式可以显著地降低数值频散，有效提高地震波正演计算的精度，适应性好，操作简便灵活。

RESERVOIR WAVE FIELD CHARACTERISTIC NUMERICAL SIMULATION IN TWO-PHASE MEDIA

Based on the equation of elastic wave propagation in two-phase media and by separating the equation of elastic wave,the dilatational wave equation in two-phase in media is derived.The higher finite-difference (FD) and the perfectly matched layer boundary conditions are used to numerical simulation.The numerical simulation of the any higher-order difference and automatic loading boundary conditions is realized.The results of the calculation show that in the two-phase media,there are the fast dilatational wave and slow dilatational wave and they are different obviously.The velocity of the fast P wave is higher.On the interface,incident fast P- wave will generate two kinds of transmission and two kinds of reflection waves.The slow P-wave has intensive attenuation.The dissipation modulus is smaller,then the slow P-wave is more obvious,vice versa.The high-order FD pattern of this method can reduce the numerical dispersion markedly,and improve the accuracy of numerical simulation effectively and with good adaptability.The operation is convenient and flexible.