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Next: Conclusions and Future Work Up: Rosales: NHNMO Previous: Theory: Non-hyperbolic moveout

Numerical examples

Figure [*] presents a simple flat-layer model. Figures [*] and [*] show the result of modeling the two-way travel time with the conventional normal moveout equation, and with the non-hyperbolic moveout equation, using an initial velocity of 1100 m/s, a velocity gradient of 125 $\mbox{s}^{-1}$ and a constant value of $\gamma=2$.

Both results (Figures [*] and [*]) present a hyperbolic moveout at near offset or small offset-to-depth ratio. This result resembles the well known theoretical presentation of Tessmer and Behle (1988). However, the non-hyperbolic moveout is dominant for large offsets and shallow depths, as can be observed in Figure [*].

 
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Figure 1
Reflectivity model.
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Figure 2
Modeled data, using the non-hyperbolic equation with a constant value of $\gamma=2$.
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Figure 3
Modeled data, using the the traditional hyperbolic equation.
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I also apply the non-hyperbolic moveout equation to a PS CMP gather from the Alba dataset acquired on the Alba oil field in the North sea. The data set is a multicomponent 3-D Ocean Bottom Seismic experiment. Figure [*] shows the original CMP gather before (left), after (center) non-hyperbolic moveout, and after traditional hyperbolic moveout (right). I use an initial velocity value of 1100 m/s, and a velocity gradient of 125 $\mbox{s}^{-1}$ and a constant $\gamma=2.0$. Note that even though the events are not totally corrected, the non-hyperbolic correction gives a better result for shallow events at large offsets. These events are flatter after the non-hyperbolic moveout correction than with the hyperbolic moveout correction.

 
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Figure 4
PS CMP gather from the Alba dataset, original gather (left), after non-hyperbolic moveout (center), and after traditional hyperbolic moveout (right). I performed non-hyperbolic moveout and traditional moveout both with an initial velocity of 1100 m/s, a velocity gradient of 125 $\mbox{s}^{-1}$ with $\gamma=2.0$ for the non-hyperbolic case.
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next up previous print clean
Next: Conclusions and Future Work Up: Rosales: NHNMO Previous: Theory: Non-hyperbolic moveout
Stanford Exploration Project
10/23/2004