基于平面波记录的绕射目标成像方法研究

Diffracting objective imaging based on plane wave record

断层、盐丘、溶洞、裂缝等非均质构造已成为现阶段碳酸盐岩高精度成像、构造及岩性解释的主要目标。然而,常规地震数据处理通常将这些非均质地质体引起的绕射波作为噪声而进行压制,即使偏移成像可以收敛归位绕射波,也因绕射波的弱振幅值和能量的快速衰减而湮没在反射能量中,因而未被有效地利用。本文根据绕射波和反射波在平面波记录上的时距曲线差异,利用平面波解构滤波方法压制平滑连续的拟线性反射波,保护和突出曲率较大、连续性较差的拟双曲绕射波,从而提高非均质绕射目标体的成像分辨率。通过对断陷模型和2DSEG/EAGE盐丘模型的试算,表明该方法可以有效改善盐丘、断层及其他小尺度非均质构造的成像质量,提高地震资料解释的精度。

Objectives of structure elucidation,lithologic interpretation and carbonate high precision imaging,such as faults,salts,karst caves and fractures et al,usually act as complicate diffractions on seismic records.However,traditional seismic data processing and imaging always suppresses diffractions as interfering noise.And although migration converge the diffractive waves,they may be hidden in the reflection energy which is disadvantage to the subsequent interpretation because of the weak amplitude and quick energy attenuation of the diffractions.According to the difference between reflection and diffraction on the plane wave record,we use plane wave destruction filtering to obtain pseudo-hyperbolic diffraction whose curvature is large by suppressing laterally continuous pseudo-linear reflection,which aims to enhance the imaging resolution of heterogenous diffracting objectives.The fault-through model and 2D SEG/EAGE salt model tests demonstrate that this method can effectively improve the imaging quality of heterogenous structures.And it can enhance the interpretive precision together with conventional interpretation.