-
摘要:
与经典的单程波深度偏移方法相比, 全声波方程波场深度偏移方法在成像质量和计算效率方面会面临新的难题, 还有诸多理论问题值得深入研究, 其中倏逝波的压制问题是全声波方程波场深度延拓及深度偏移方法面对的一项特殊挑战.为了解决该问题, 本文提出了两种新的倏逝波压制策略.策略Ⅰ是以经典频率-波数域方法为基础, 提出广义低通滤波器方法; 策略Ⅱ是以能量守恒原理为基础, 来解决波场延拓中倏逝波的振幅爆炸问题.对梯度速度模型的脉冲响应计算表明, 本文提出的两种倏逝波压制策略在横向速度变化剧烈情况下的数值结果都是稳定的, 并且能够实现与有限差分方法相同的波场延拓计算精度.在对盐丘模型成像时, 在相同计算参数下, 本文所提新策略解决了在使用传统低通滤波器压制倏逝波时无法对高角度构造进行准确成像的缺点.相较于压制倏逝波的谱投影方法, 本文所提新策略不仅在成像质量上达到了与之相同的水平, 而且具有更高的计算效率.通过一系列数值模拟实验表明: 与传统倏逝波压制策略相比, 本文所提新策略在实现全声波方程波场深度延拓及成像时, 更好地平衡了计算效率和计算精度, 具有更好的实用价值.
Abstract:Evanescent wave suppression presents a special challenge to full-wave-equation wavefield depth-extrapolation and related depth migration methods. This is because, in contrast to classic one-way depth migration, more challenges in both imaging quality and computational cost are involved in full-wave-equation wavefield depth migration. To address this challenge, we propose two new methods for evanescent wave suppression. Method Ⅰ is an extension of the classic one-way frequency-wavenumber domain method, named generalized low-pass filter; Method Ⅱ is the energy norm method by using the energy conservation law to identify and eliminate energy explosion of evanescent waves. Impulse responses in a gradient velocity prove that our proposed two methods are stable and enable to achieve the similar wavefield extrapolation accuracy as the finite different method. When imaging the standard Salt model, with the same hardware configuration and parallelization implementation, the new methods solve the weakness of using the conventional low-pass filter in suppressing evanescent waves and achieve the similar imaging quality as that of full-wave-equation depth migration by using the spectral projector in suppressing evanescent waves, but with much less computational cost. The proposed methods provide two numerical algorithms to efficiently suppress evanescent waves in performing full-wave-equation wavefield depth extrapolation and migration.
-
Key words:
- Full acoustic equation /
- Depth-extrapolation /
- Evanescent wave /
- Numerical simulation
-
-
图 1
深度偏移与RTM波场延拓示意图
Figure 1.
Schematic diagram of depth migration and RTM wave field continuation
图 6
利用不同偏移方法计算得到的成像剖面
Figure 6.
Imaging sections calculated by using different migration methods
图 8
基于策略Ⅰ，通过使用不通的“群组”大小所得到的成像剖面
Figure 8.
Imaging sections achieved with our proposed method Ⅰ by using different size of subgroup
表 1
基于策略Ⅰ的全声波方程深度偏移方法在不同CPU核心数的运行时间
Table 1.
The running time of our proposed method Ⅰ by using multiple CPU cores
核心数/个 4 8 16 28 时间/s 569 372 340 283 
下载: 导出CSV
表 2
基于策略Ⅱ的全声波方程深度偏移方法在不同CPU核心数的运行时间
Table 2.
The running time of our proposed method Ⅱ by using multiple CPU cores
核心数/个 4 8 16 28 时间/s 387 238 179 122
下载: 导出CSV
表 3
不同偏移方法的计算时间
Table 3.
Computational time of different migration methods
偏移方法 方法#1 方法#2 本文所提策略Ⅰ 本文所提策略Ⅱ 时间/s 501 10736 1262 825 注：表中方法#1表示基于经典低通滤器的全声波方程深度偏移方法，方法#2表示基于谱投影方法的全声波方程深度偏移方法.
下载: 导出CSV
表 4
基于策略Ⅰ的不同“群组”大小的计算时间
Table 4.
Computational time by using different size of group with strategy Ⅰ
群组大小 40 60 80 混合 时间/s 134 95 75 127
下载: 导出CSV
-
Baysal E, Kosloff D D, Sherwood J W C. 1983. Reverse time migration. Geophysics, 48(11): 1514-1524. doi: 10.1190/1.1441434
Cheng J B, Wang H Z, Ma Z T. 2001. Pre-stack depth migration with finite difference method in frequency-space domain. Chinese Journal of Geophysics (in Chinese), 44(3): 389-395.
Gazdag J, Sguazzero P. 1984. Migration of seismic data by phase shift plus interpolation. Geophysics, 49(2): 124-131. doi: 10.1190/1.1441643
Jia X F, Wu R S. 2009. Superwide-angle one-way wave propagator and its application in imaging steep salt flanks. Geophysics, 74(4): S75-S83. doi: 10.1190/1.3124686
Kosloff D D, Baysal E. 1983. Migration with the full acoustic wave equation. Geophysics, 48(6): 677-687. doi: 10.1190/1.1441498
Le Rousseau J H, de Hoop M V. 2001. Modeling and imaging with the scalar generalized-screen algorithms in isotropic media. Geophysics, 66(5): 1551-1568. doi: 10.1190/1.1487101
Liu H W, Li B, Liu H, et al. 2010. The algorithm of high order finite difference pre-stack reverse time migration and GPU implementation. Chinese Journal of Geophysics (in Chinese), 53(7): 1725-1733, doi: 10.3969/j.issn.0001-5733.2010.07.024.
Liu X M, Chen W G, Tang J, et al. 2021. Application of geologically constrained velocity modeling to PSDM in complex tectonic zones. Progress in Geophysics (in Chinese), 36(2): 759-765, doi: 10.6038/pg2021EE0200.
Liu X W, Liu H. 2002. Status and progress on wave equation migration methods. Progress in Geophysics (in Chinese), 17(4): 582-591. doi: 10.3969/j.issn.1004-2903.2002.04.004
Ristow D, Rühl T. 1994. Fourier finite-difference migration. Geophysics, 59(12): 1882-1893. doi: 10.1190/1.1443575
Sandberg K, Beylkin G. 2009. Full-wave-equation depth extrapolation for migration. Geophysics, 74(6): WCA121-WCA128. doi: 10.1190/1.3202535
Wu R S. 1994. Wide-angle elastic wave one-way propagation in heterogeneous media and an elastic wave complex-screen method. Journal of Geophysical Research: Solid Earth, 99(B1): 751-766. doi: 10.1029/93JB02518
Xu S Y, Jin S W. 2006. Wave equation migration of turning waves. //SEG Technical Program Expanded Abstracts. SEG, 2328-2332.
Yang R H. 2021. Analysis of effect of velocity error on reverse time migration. Progress in Geophysics (in Chinese), 36(4): 1630-1639, doi: 10.6038/pg2021FF0060.
Yang R H, Chang X, Liu Y K. 2010. The influence factors analyses of imaging precision in pre-stack reverse time migration. Chinese Journal of Geophysics (in Chinese), 53(8): 1902-1913, doi: 10.3969/j.issn.0001-5733.2010.08.016.
You J C, Cao J X. 2020. Full-wave-equation depth extrapolation for migration using matrix multiplication. Geophysics, 85(6): S395-S403. doi: 10.1190/geo2019-0323.1
You J C, Li G C, Liu X W, et al. 2016. Full-wave-equation depth extrapolation for true amplitude migration based on a dual-sensor seismic acquisition system. Geophysical Journal International, 204(3): 1462-1476. doi: 10.1093/gji/ggv535
You J C, Pan N D, Liu W, et al. 2022. Efficient wavefield separation by reformulation of two-way wave-equation depth-extrapolation scheme. Geophysics, 87(4): S209-S222. doi: 10.1190/geo2021-0629.1
You J C, Wu R S, Liu X W, et al. 2018. Two-way wave equation-based depth migration using one-way propagators on a bilayer sensor seismic acquisition system. Geophysics, 83(3): S271-S278. doi: 10.1190/geo2017-0172.1
Zhang J, McMechan G A. 1997. Turning wave migration by horizontal extrapolation. Geophysics, 62(1): 291-297. doi: 10.1190/1.1444130
Zhang X P, Li Q C, Ma J Q, et al. 2022. Optimization of prestack depth migration stack operator in angle domain. Progress in Geophysics (in Chinese), 37(4): 1689-1696, doi: 10.6038/pg2022FF0176.
Zhang Y. 2006. The theory of true amplitude one-way wave equation migration. Chinese Journal of Geophysics (in Chinese), 49(5): 1410-1430.
Zhou H, Chen H M, Li XX, et al. 2014. Methods for improving computational efficiency of arbitrarily wide-angle wave equation and suppressing evanescent wave noises. Chinese Journal of Geophysics (in Chinese), 57(4): 1188-1198, doi: 10.6038/cjg20140416.
程玖兵, 王华忠, 马在田. 2001. 频率-空间域有限差分法叠前深度偏移. 地球物理学报, 44(3): 389-395. http://www.geophy.cn/article/id/cjg_3628
李振春. 2014. 地震偏移成像技术研究现状与发展趋势. 石油地球物理勘探, 49(1): 1-21.
刘红伟, 李博, 刘洪等. 2010. 地震叠前逆时偏移高阶有限差分算法及GPU实现. 地球物理学报, 53(7): 1725-1733, doi: 10.3969/j.issn.0001-5733.2010.07.024.
刘喜武, 刘洪. 2002. 波动方程地震偏移成像方法的现状与进展. 地球物理学进展, 17(4): 582-591. doi: 10.3969/j.issn.1004-2903.2002.04.004
刘旭明, 陈文贵, 唐进等. 2021. 地质约束速度建模在复杂构造区叠前深度偏移中的应用. 地球物理学进展, 36(2): 759-765, doi: 10.6038/pg2021EE0200.
马在田. 2002. 论反射地震偏移成像. 勘探地球物理进展, 25(3): 1-5.
杨仁虎. 2021. 逆时偏移速度误差影响分析. 地球物理学进展, 36(4): 1630-1639, doi: 10.6038/pg2021FF0060.
杨仁虎, 常旭, 刘伊克. 2010. 叠前逆时偏移影响因素分析. 地球物理学报, 53(8): 1902-1913, doi: 10.3969/j.issn.0001-5733.2010.08.016.
张选朋, 李庆春, 马见青等. 2022. 角度域叠前深度偏移叠加算子优化. 地球物理学进展, 37(4): 1689-1696, doi: 10.6038/pg2022FF0176.
张宇. 2006. 振幅保真的单程波方程偏移理论. 地球物理学报, 49(5): 1410-1430. http://www.geophy.cn/article/id/cjg_332
张宇, 徐升, 张关泉等. 2007. 真振幅全倾角单程波方程偏移方法. 石油物探, 46(6): 582-587, 642. doi: 10.3969/j.issn.1000-1441.2007.06.010
周辉, 陈汉明, 李绪宣等. 2014. 提高任意广角波动方程计算效率及压制倏逝波干扰方法. 地球物理学报, 57(4): 1188-1198, doi: 10.6038/cjg20140416.
-
图(8)
表(4)
计量
- 文章访问数:
- PDF下载数:
- 施引文献: 0