Seismic data processing 14, stacking&migration2
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This document summarizes seismic data processing techniques like stacking and migration. It discusses Huygen's principle, how diffraction works using examples, and how stacking can be used to obtain diffraction points by using the proper velocity. It also explains how migration works by applying concepts to multiple diffractor points, and how a dipping reflector can be mapped through migration by a cosine term. The document provides examples and illustrations of key concepts in seismic data processing like diffraction stacking, four point diffractors, and addressing issues like bow-tie phenomena through migration techniques.
Seismic data processing 14, stacking&migration2
- 1. Seismic Data Processing Lecture 14 Stacking and migration Dr Amin Khalil School of Physics, USM
- 6. The time for a diffracting point located at (xd , Zd ) is given by: This equation represent hyperbola like the one seen at the following figure.
- 7. This figure shows the diffractor to the left and its corresponding time on the zero offset seismic section.
- 8. Diffraction stacking Cont’d In early days, Before the computer era, people used stacking along the hyperbola in order to obtain the diffraction point. This require the knowledge of the velocity to carry out stacking. In case that we have more than one diffraction point with different velocities we apply stacking for each hyperbola with its proper stacking velocity.
- 9. Diffraction stacking Cont’d In early computer age the following relation is used:
- 10. In the preceding slides we dealt with single point diffraction. This principle can be further used to image the whole refractor by consider all other diffractor point. When the separation between diffraction points become infinitesimally small, the reflector is then determined (Huygen’s principle). An example of this is shown in the next slide, where the concept is applied to four diffraction points.
- 11. Four points diffractor If the points separation is infinitely small, a reflector then can be mapped.
- 13. In the present case the migration is applied by multiplying by 1/cos q, where q is the dip angle. As illustrated in the following fig.
- 23. Thank you