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常规地震处理中,正常时差校正(NMO)是为了增强共深度点和共中心点迭加剖面的反射信息。然而,当存在断层时,来自两断块的反射相互干扰及其边缘绕射限制了断层位置的确定,而且,迭后偏移破坏了绕射曲线图,则进一步抑制绕射中心的正确成像。本文提出由加强绕射点的信号幅值来帮助解释绕射边缘的一项新技术。它包括对假定绕射位置的数据进行时差校正和振幅校正。最大绕射振幅出现在绕射点上方的炮检距中点接收道。由于在中点两边的绕射振幅迅速衰减,因此必须进行适当的振幅校正。此外由于所有道都有绕射信息,将这些道迭加可形成相对于某一绕射点的一个迭加道,设想每一接收点下都存在绕射点,重复上述迭加过程即可形成共断点(CFP)迭加剖面,该剖面用强振幅来显示绕射点位置。用有噪音和无噪音两种合成地震记录来验证该方法,结果表明相当有效,但对用于时差校正的速度模型十分敏感,因此常用 NMO 迭加速度模型来突出绕射点位置。最后,用该技术处理了艾伯塔省公主井南部的实际野外资料。
In conventional seismic processing, Normal Time Difference Correction (NMO) is to enhance the reflection information of the common profile and the common profile. However, when there is a fault, the reflection mutual interference from two fault blocks and its edge diffraction limit the determination of the fault location, and the overlap migration destroys the diffraction curve, which further suppresses the correct imaging of the diffraction center. This paper proposes a new technique to help explain the diffraction edge by enhancing the signal amplitude at the diffraction point. It consists of time-of-flight correction and amplitude correction of the data at assumed diffraction positions. The maximum diffraction amplitude appears at the mid-point receiving channel above the diffraction point. Since the diffraction amplitudes on both sides of the midpoint are rapidly attenuated, proper amplitude correction must be performed. In addition, since all the paths have diffraction information, these paths are added to form an overlap with respect to a diffraction point. Suppose there is a diffraction point under each reception point, and the above superposition process can be repeated Common Break Point (CFP) A superimposed section that shows the diffraction point position with strong amplitude. The method is validated with both synthetic and noisy synthetic seismograms, and the results show that the method is quite effective but sensitive to the velocity model used for time-of-flight correction. Therefore, the NMO superposition model is often used to highlight the diffraction point location. Finally, this technique was used to process actual field data in the southern part of Princess Margaret, Alberta.