Damped wave-equation-based first-arrival traveltime tomography using the embedded boundary method
Damped wave-equation-based first-arrival traveltime tomography using the embedded boundary method
复制标题
使用嵌入边界法的基于阻尼波动方程的初至走时层析成像
DOI：
10.1190/geo2020-0233.1
复制
发表时间：
2021
期刊：
影响因子：
3.3
通讯作者：
S. Pyun
中科院分区：
文献类型：
--
作者：
Yunhui Park;S. Pyun
初至走时层析成像（FATT）用于描绘浅层速度结构，以识别石油勘探中的静态效应，以及表征近地表的岩土工程目的。由于FATT通常用于陆地地震数据处理，因此在进行波基层析成像时，特别是在进行波基层析成像时，需要考虑不规则地形。然而，标准的笛卡尔有限差分法不能很好地处理不规则的地形。因此，嵌入边界法（EBM）被纳入频域阻尼波方程，以正确地描述不规则地形。所开发的建模算法用于计算初至走时和执行FATT。基于EBM的建模算法利用镜像原理，在规则网格上精确地描述数值速度模型的不规则表面。利用倾斜和复杂地表两种均质速度模型验证了基于EBM的走时计算的准确性。验证结果表明，我们的算法是不受楼梯近似。FATT然后应用于合成和真实的数据，以证明所开发的算法的速度模型与复杂的地形的适用性。对于真实的数据实例，使用反演的速度模型来施加静校正。处理结果表明，地震同相轴的连续性得到了改善，从而证实了FATT方法的准确性。
First-arrival traveltime tomography (FATT) is used to delineate shallow velocity structures to identify static effects in oil exploration as well as to characterize the near surface for geotechnical purposes. Because FATT is generally used for land seismic data processing, it becomes necessary to consider irregular topography especially when performing wave-based tomography. However, the standard Cartesian finite-difference method cannot properly handle irregular topography. Hence, the embedded boundary method (EBM) is incorporated into the frequency-domain damped-wave equation to correctly describe irregular topography. The developed modeling algorithm is used to calculate first-arrival traveltimes and to perform FATT. The EBM-based modeling algorithm accurately describes the irregular surfaces of numerical velocity models on a regular mesh by exploiting the mirror image principle. The accuracy of the EBM-based traveltime calculation is validated by using two homogeneous velocity models with dipping and complex surfaces. The validation results demonstrate that our algorithm is unaffected by the staircase approximation. FATT is then applied to synthetic and real data to demonstrate the applicability of the developed algorithm to velocity models with complex topography. For the real data example, the inverted velocity model is used to apply static corrections. The processing results demonstrate an improvement in the continuity of seismic events, thus confirming the accuracy of the developed FATT method.