Diffraction separation by plane-wave prediction filtering  

平面波预测滤波分离绕射波方法研究（英文）

作　　者：孔雪[1] 王德营 李振春[3] 张瑞香[1] 胡秋媛[1] 

机构地区：[1]中国石油大学胜利学院油气工程学院,山东东营257061 [2]山东科技大学地球科学与工程学院,山东青岛266590 [3]中国石油大学(华东)地球科学与技术学院,山东青岛266555

出　　处：《Applied Geophysics》2017年第3期399-405,461,共8页应用地球物理（英文版）

基　　金：funded jointly by the National Natural Science Foundation of China(No.41104069);the National Key Basic Research Program of China(973 Program:2011CB202402);the Shandong University Science and Technology Planning Project(No.J17KA197);the College of Petroleum Engineering in Shengli College China University of Petroleum"Chunhui Project"(No.KY2015003)

摘　　要：Seismic data processing typically deals with seismic wave reflections and neglects wave diffraction that affect the resolution. As a general rule, wave diffractions are treated as noise in seismic data processing. However, wave diffractions generally originate from geological structures, such as fractures, karst caves, and faults. The wave diffraction energy is much weaker than that of the reflections. Therefore, even if wave diffractions can be traced back to their origin, their energy is masked by that of the reflections. Separating and imaging diffractions and reflections can improve the imaging accuracy of diffractive targets. Based on the geometrical differences between reflections and diffractions on the plane-wave record; that is, reflections are quasi-linear and diffractions are quasi-hyperbolic, we use plane-wave prediction fltering to separate the wave diffractions. First, we estimate the local slope of the seismic event using plane- wave destruction filtering and, then, we predict and extract the wave reflections based on the local slope. Thus, we obtain the diffracted wavefield by directly subtracting the reflected wavefield from the entire wavefield. Finally, we image the diffracted wavefield and obtain high-resolution diffractive target results. 2D SEG salt model data suggest that the plane-wave prediction filtering eliminates the phase reversal in the plane-wave destruction filtering and maintains the original wavefield phase, improving the accuracy of imaging heterogeneous objects.常规地震资料处理通常将地震波场当作反射波处理,绕射波的存在会降低处理成果的分辨率,因此将其当做干扰噪音进行压制。然而,绕射波往往包含了非常重要的地质信息(裂缝、溶洞、断层等特殊构造),即使偏移将绕射波归位,因为绕射波能量较弱也会被反射同相轴遮盖。将反射波和绕射波进行分离并单独成像处理,将提高绕射目标构造的成像精度。根据在平面波域反射波拟线性、绕射波拟双曲的形态差异,本文利用平面波预测滤波技术对平面波炮记录进行波场分离。首先,采用平面波解构滤波器估算地震同相轴的局部倾角,利用局部倾角信息预测并提取反射波,然后从全波场中减去反射波,间接分离出绕射波,对绕射波成像可获得高分辨率的绕射目标体成像结果。通过对2D SEG盐丘模型进行波场分离与成像,分析表明:本文采用的平面波预测滤波技术解决了平面波解构滤波的极性反转问题,保持了绕射波原有的相位信息,保证了波场分离后的绕射波场保真度,成像结果表明用平面波预测滤波方法提取的绕射波进行偏移可改善非均质目标体的成像精度。

关 键 词：Plane wave prediction filter SEPARATION DIFFRACTION 

分 类 号：P631.44[天文地球—地质矿产勘探]