波阻抗映射法外推

IMPEDANCE MAPPING EXTRAPOLATION

首先介绍了自适应滤波的方法和波阻抗映射法外推的基本原理．在小反射系数的假设条件下推导了对数波阻抗和地震道之间近似为线性映射的关系，应用自适应滤波的方法可以实现这种映射．实际资料的试算结果表明，该方法能够提供分辨率明显高于常规方法的波阻抗或层速度剖面，并与测井资料较吻合．因此，它作为测井约束反演的补充手段，是一种可用于开发地震的新方法．最后讨论了映射法波阻抗反演的局限性．

A mapping approach to impedance extrapolation is presented in this paper. With the assumption of small reflection coefficients, it is derived that there exists an approximately linear mapping relationship between logarithmic impedances and seismic traces. Such a mapping can be realized by applying adaptive filtering. The test result of field data is given. It is shown that the derived impedance or interval velocity profiles bear higher resolution and better well logs correlation than those derived from the conventional method. It turns out to be a kind of supplementary means to inversion technique in production seismology. At last the limitation of the mapping approach is discussed.