Least-squares migration is an advanced imaging technique capable of producing images with improved spatial resolution, balanced illumination, and reduced migration artifacts; however, the prohibitive computational cost poses a great challenge for its practical application. We have incorporated the beam methodology into the implementation of Kirchhoff time modeling/migration and developed a fast common-offset least-squares Kirchhoff beam time migration (LSKBTM). Different from conventional Kirchhoff time modeling/migration in which the seismic data are modeled/migrated trace by trace, the mapping operation in Kirchhoff beam time modeling/migration is performed in terms of beam components and is performed only at sparsely sampled beam centers. Therefore, the computational cost of LSKBTM is significantly reduced in comparison with that of least-squares Kirchhoff time migration (LSKTM). In addition, based on the second-order Taylor expansion of the diffraction traveltime, we introduce a quadratic correction term into the inverse/forward local slant stacking, effectively enhancing the computational accuracy of LSKBTM. We used 2D synthetic and 3D field data examples to verify the effectiveness of our method. Our results indicate that LSKBTM can produce images comparable with those of LSKTM, but at considerably reduced computational cost.

中文翻译：

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使用波束方法加速最小二乘基尔霍夫时间迁移

最小二乘迁移是一种先进的成像技术，能够产生具有改善的空间分辨率，平衡的照明和减少的迁移伪影的图像；然而，过高的计算成本对其实际应用提出了巨大的挑战。我们将波束方法纳入了Kirchhoff时间建模/迁移的实现中，并开发了一种快速的公共偏移最小二乘Kirchhoff波束时间迁移（LSKBTM）。与传统的基尔霍夫时间建模/迁移中的地震数据是逐迹地建模/迁移轨迹不同，基尔霍夫波束时间建模/迁移中的映射操作是根据波束分量执行的，并且仅在稀疏采样的波束中心进行。所以，与最小二乘基尔霍夫时间迁移（LSKTM）相比，LSKBTM的计算成本大大降低。另外，基于衍射传播时间的二阶泰勒展开，我们在逆/前向局部倾斜叠加中引入了二次校正项，有效地提高了LSKBTM的计算精度。我们使用2D合成和3D现场数据示例来验证我们方法的有效性。我们的结果表明，LSKBTM可以产生与LSKTM相当的图像，但计算成本却大大降低。有效地提高了LSKBTM的计算精度。我们使用2D合成和3D现场数据示例来验证我们方法的有效性。我们的结果表明，LSKBTM可以产生与LSKTM相当的图像，但计算成本却大大降低。有效地提高了LSKBTM的计算精度。我们使用2D合成和3D现场数据示例来验证我们方法的有效性。我们的结果表明，LSKBTM可以产生与LSKTM相当的图像，但计算成本却大大降低。