Tunnel seismic prediction (TSP) faces challenges in accurately imaging geological anomalies due to the confined spaces of subterranean tunnels in observation, differing markedly from the open spaces encountered in surface seismic exploration. Conventional prestack depth migration approaches, such as Kirchhoff and reverse time migration (RTM), are prone to producing annular artifacts centered on the survey line, as these standard imaging techniques cannot discriminate the propagation direction of reflected waves, imaging them indistinctly onto all possible imaging points. Although previous studies utilizing the polarization attributes of seismic waves can mitigate such symmetrical artifacts to some extent, they fall short of fully suppressing them, particularly for reflectors at small azimuth angles relative to the survey line. This article proposes an innovative solution, whole-space Kirchhoff polarization depth migration (WSKPDM), designed to thoroughly eliminate these migration artifacts. WSKPDM utilizes polarization information extracted from multiple seismic traces to ascertain the true propagation directions of reflected waves, thereby imaging only veritable reflection points. This effectively removes symmetrical artifacts, enhancing the visualization of subsurface geological structure. Testing on synthetic seismic data from diverse fault models and real-world tunnel data shows that WSKPDM surpasses conventional techniques in imaging accuracy. Moreover, WSKPDM demonstrates robust noise immunity even with random noise and reversed polarity in seismic data. With minimal adjustments to account for the distinct polarization directions of S-wave and P-wave, WSKPDM also allows efficient S-wave imaging. This promising WSKPDM method significantly improves the clarity and reliability of TSP imaging, providing a crucial tool for safer and more efficient tunnel construction.

中文翻译：

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3维全空间隧道地震成像基尔霍夫深度偏移中对称伪影的消除


由于地下隧道观测中的空间有限，与地面地震勘探中遇到的开放空间明显不同，隧道地震预测（TSP）面临着准确成像地质异常的挑战。传统的叠前深度偏移方法，例如基尔霍夫偏移和逆时偏移（RTM），很容易产生以测量线为中心的环形伪影，因为这些标准成像技术无法区分反射波的传播方向，将它们模糊地成像到所有可能的成像上点。尽管先前利用地震波偏振属性的研究可以在一定程度上减轻这种对称伪影，但它们无法完全抑制它们，特别是对于相对于测量线处于小方位角的反射体。本文提出了一种创新的解决方案，即全空间基尔霍夫偏振深度偏移（WSKPDM），旨在彻底消除这些偏移伪影。 WSKPDM 利用从多个地震道中提取的偏振信息来确定反射波的真实传播方向，从而仅对真正的反射点进行成像。这有效地消除了对称伪影，增强了地下地质结构的可视化。对来自不同断层模型的合成地震数据和真实隧道数据的测试表明，WSKPDM 在成像精度方面超越了传统技术。此外，即使地震数据中存在随机噪声和反极性，WSKPDM 也能表现出强大的抗噪能力。通过最小的调整来考虑 S 波和 P 波的不同偏振方向，WSKPDM 还可以实现高效的 S 波成像。 这种有前途的 WSKPDM 方法显着提高了 TSP 成像的清晰度和可靠性，为更安全、更高效的隧道施工提供了重要工具。