Least-squares reverse time migration based on the viscoacoustic VTI pure qP-wave equation
Least-squares reverse time migration based on the viscoacoustic VTI pure qP-wave equation
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DOI：
10.3389/feart.2022.998986
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发表时间：
2022-09
期刊：
影响因子：
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通讯作者：
Shanshan Zhang;B. Gu;Zhenchun Li
中科院分区：
文献类型：
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作者：
Shanshan Zhang;B. Gu;Zhenchun Li
随着油气勘探的深入和勘探目标的日益复杂，地下介质的各向异性和非弹性对地震成像的影响不容忽视。基于线性反演的思想，提出了最小二乘逆时偏移方法，有效地解决了RTM的幅值不平衡、分辨率低、成像噪声严重等问题。本文基于粘声纯qp波方程，推导了相应的反偏移算子、伴随算子和梯度敏感核，提出了VTI介质中粘声纯qp波的最小二乘逆时偏移成像算法。在迭代反演过程中，近似求解Hessian逆，实现稳定的衰减补偿。最后，通过模型试验和现场数据验证了所提出的粘声VTI最小二乘逆时偏移成像算法的有效性和适用性。数值计算结果表明，该方法可以补偿衰减引起的振幅损失和相位畸变，并校正反射界面的各向异性失调，提高了成像剖面的精度和分辨率。
With the deepening of oil and gas exploration and the increasing complexity of exploration targets, the influence of anisotropy and anelasticity of subsurface media on seismic imaging cannot be ignored. The least-squares reverse time migration is developed on the idea of linear inversion, which can effectively solve the amplitude imbalance, low resolution, and serious imaging noise problems of RTM. In this paper, based on the viscoacoustic pure qP-wave equation, the corresponding demigration operator, adjoint operator, and gradient-sensitive kernel are derived, and the least-square reverse time migration imaging algorithm of viscoacoustic pure qP-wave in VTI medium is proposed. During iterative inversion, the inverse of Hessian is approximately solved to achieve stable attenuation compensation. Finally, we verify the effectiveness and applicability of the proposed viscoacoustic VTI least-squares reverse time migration imaging algorithm through the model tests and field data. The numerical results show that the method can compensate for the amplitude loss and phase distortion caused by attenuation, and correct the anisotropy-induced misalignment of the reflection interfaces, which improves the accuracy and resolution of the imaging profile.