Register      Login
Exploration Geophysics Exploration Geophysics Society
Journal of the Australian Society of Exploration Geophysicists
RESEARCH ARTICLE

Imaging tilted transversely isotropic media with a generalised screen propagator

Sung-Il Shin 1 Joongmoo Byun 2 3 Soon Jee Seol 2
+ Author Affiliations
- Author Affiliations

1 SK Building, 26 Jongno, Jongno-gu, Seoul, 110-728, Korea.

2 Department of Natural Resources and Geoenvironmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Korea.

3 Corresponding author. Email: jbyun@hanyang.ac.kr

Exploration Geophysics 46(4) 349-358 https://doi.org/10.1071/EG14113
Submitted: 11 November 2014  Accepted: 12 November 2014   Published: 13 January 2015
Originally submitted to KSEG 14 August 2014, accepted 28 October 2014  

Abstract

One-way wave equation migration is computationally efficient compared with reverse time migration, and it provides a better subsurface image than ray-based migration algorithms when imaging complex structures. Among many one-way wave-based migration algorithms, we adopted the generalised screen propagator (GSP) to build the migration algorithm. When the wavefield propagates through the large velocity variation in lateral or steeply dipping structures, GSP increases the accuracy of the wavefield in wide angle by adopting higher-order terms induced from expansion of the vertical slowness in Taylor series with each perturbation term. To apply the migration algorithm to a more realistic geological structure, we considered tilted transversely isotropic (TTI) media. The new GSP, which contains the tilting angle as a symmetric axis of the anisotropic media, was derived by modifying the GSP designed for vertical transversely isotropic (VTI) media. To verify the developed TTI-GSP, we analysed the accuracy of wave propagation, especially for the new perturbation parameters and the tilting angle; the results clearly showed that the perturbation term of the tilting angle in TTI media has considerable effects on proper propagation. In addition, through numerical tests, we demonstrated that the developed TTI-GS migration algorithm could successfully image a steeply dipping salt flank with high velocity variation around anisotropic layers.

Key words: anisotropy, generalised screen, prestack migration, tilted transversely isotropic.


References

Abramowitz, M., and Stegun, I., 1972, Handbook of mathematical functions with formulas, graphs, and mathematical tables: Dover.

Bale, R., 2007, Phase-shift migration and the anisotropic acoustic wave equation: 69th Conference and Exhibition, EAGE, Extended Abstract, C021.

Claerbout, J., 1985, Imaging the earth’s interior: Blackwell Scientific Publications, Inc.

Gazdag, J., 1978, Wave equation migration with the phase-shift method: Geophysics, 43, 1342–1351
Wave equation migration with the phase-shift method:Crossref | GoogleScholarGoogle Scholar |

Gazdag, J., and Sguazzero, P., 1984, Migration of seismic data by phase shift plus interpolation: Geophysics, 49, 124–131
Migration of seismic data by phase shift plus interpolation:Crossref | GoogleScholarGoogle Scholar |

Han, Q., and Wu, R., 2005, A one-way dual-domain propagator for scalar qP-waves in VTI media: Geophysics, 70, D9–D17
A one-way dual-domain propagator for scalar qP-waves in VTI media:Crossref | GoogleScholarGoogle Scholar |

Jang, S., Yang, D., Suh, S., and Ko, J., 2004, Prestack depth migration using split-step fourier migration for VTI media: Journal of Korean Society for Geosystem Engineering, 41, 160–166

Jaramilo, H, and Larner, K, 1995, Prestack migration error in transversely isotropic media: CWP Research Report, 178, 185–213

Jenkins, M. A., and Traub, J. F., 1970, A three-stage variable-shift iteration for polynomial zeros and its relation to generalized Rayleigh iteration: Numerische Mathematik, 14, 252–263
A three-stage variable-shift iteration for polynomial zeros and its relation to generalized Rayleigh iteration:Crossref | GoogleScholarGoogle Scholar |

Joncour, F., Derouillat, J., Duquet, B., and Svay-Lucas, J., 2003, Stable wave field paraxial extrapolator for P and S waves in VTI media: 73rd Annual International Meeting, SEG, Expanded Abstracts, 965–968.

Larner, K., and Cohen, J., 1993, Migration error in transversely isotropic media with linear velocity variation in depth: Geophysics, 58, 1454–1467
Migration error in transversely isotropic media with linear velocity variation in depth:Crossref | GoogleScholarGoogle Scholar |

Le Rousseau, J., 1997, Depth migration in heterogeneous, transversely isotropic media with the phase-shift-plus-interpolation method: 67th Annual International Meeting, SEG, Expanded Abstracts, 1703–1706.

Le Rousseau, J., and de Hoop, M., 2001a, Modeling and imaging with the scalar generalized-screen algorithms in isotropic media: Geophysics, 66, 1551–1568
Modeling and imaging with the scalar generalized-screen algorithms in isotropic media:Crossref | GoogleScholarGoogle Scholar |

Le Rousseau, J., and de Hoop, M., 2001b, Scalar generalized-screen algorithms in transversely isotropic media with a vertical symmetry axis: Geophysics, 66, 1538–1550
Scalar generalized-screen algorithms in transversely isotropic media with a vertical symmetry axis:Crossref | GoogleScholarGoogle Scholar |

Mittet, R., Sollie, R., and Hokstad, K., 1995, Prestack depth migration with compensation for absorption and dispersion: Geophysics, 60, 1485–1494
Prestack depth migration with compensation for absorption and dispersion:Crossref | GoogleScholarGoogle Scholar |

Nolte, B., 2005, Converted-wave migration for VTI media using Fourier finite-difference depth extrapolation: 67th Technical Conference and Exhibition, EAGE, Extended Abstracts, P001.

Ristow, D., and Rühl, T., 1994, Fourier finite-difference migration: Geophysics, 59, 1882–1893
Fourier finite-difference migration:Crossref | GoogleScholarGoogle Scholar |

Shan, G., and Biondi, B. L., 2005, 3D wavefield extrapolation in laterally-varying tilted TI media: 75th Annual International Meeting, SEG, Expanded Abstracts, 104–107.

Stoffa, P., Fokkema, J., de Luna Freire, R., and Kessinger, W., 1990, Split-step Fourier migration: Geophysics, 55, 410–421
Split-step Fourier migration:Crossref | GoogleScholarGoogle Scholar |

Wu, R.-S., and Huang, L.-J., 1992, Scattered field calculation in heterogeneous media using a phase-screen propagator: 62nd Annual International Meeting, SEG, Expanded Abstracts, 1289–1292.