Zero-offset migration |

A little geometry gives simple expressions for the horizontal and vertical position errors on the zero-offset section, which are to be corrected by migration. Figure 5.2 defines the required quantities for a reflection event recorded at corresponding to the reflectivity at .

reflkine
Geometry of the normal ray of length and the vertical ``shaft''
of length for
a zero-offset experiment above a dipping reflector.
Figure 2. | |
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where is the constant propagation velocity. Geometry of the triangle shows that the true depth of the reflector at is given by

and the lateral shift between true position and false position is given by

It is conventional to rewrite equation (5.2) in terms of two-way

Thus both the vertical shift and the horizontal shift are seen to vanish when the dip angle is zero.

Zero-offset migration |

2009-03-16