Sobretiempo por distancia de onda convertida

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Con las secciones de trazas comunes de la onda C, el sobretiempo por distancia no será simétrico y la expresión de tiempo de llegada es [1]

$\displaystyle t_C^2 = t_{CO}^2 \left[ 1 + C_1 \left( \frac{x}{t_{CO} V_{CNMO} }\right) + \frac{x^2}{t_{CO}^2 V_{CNMO}^2 } + C_3 \left( \frac{x}{t_{CO} V_{CNMO} }\right)^3 - \frac{ C_4 \left( \displaystyle \frac{x}{t_{CO} V_{CNMO}}\right)^4 }{ 1 + C_5 \left( \displaystyle \frac{x}{t_{CO} V_{CNMO}} \right)^2 } \right] .$

ecuación (5.2.5), Thomsen (2002).

The non-hyperbolic moveout coefficent ${\displaystyle C_{1}}$ tends to be small and may be ignored for large offsets. Nonhyperbolic moveout parameter ${\displaystyle C_{3}}$ tends to be positive.

The extra coefficient is defined by

$\displaystyle C_5 = \frac{C_4}{\left( 1 - \displaystyle \frac{V_{CNMO}^2 }{V_{P90}^2 } \right) } \qquad \mbox{where} \qquad V_{P90} = V_{PNMO} ( 1 + 2 \eta )$

Thus, the moveout equation involves odd as well as even powers of x (see Thomsen, 2002: 5;1-2).

References

1. Thomsen, L. (2002), Understanding seismic anisotropy in exploration and exploitation, 2002 Distinguished Instructor Short Course, Distinguished Instructor Series, No. 5, Society of Exploration Geophysicists