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Next: Conclusions Up: Structural uncertainty of time-migrated Previous: Uncertainty in velocity picking

Structure uncertainty

arr
arr
Figure 7.
Estimated structural uncertainty in the seismic image from Figure 3, displayed as displacements.
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hors
hors
Figure 8.
Estimated structural uncertainty in the seismic image from Figure 3, displayed as horizon uncertainties.
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Putting structural sensitivity and velocity uncertainty together, we can define structural uncertainty simply as their product:

$\displaystyle \delta t$ $\textstyle =$ $\displaystyle \displaystyle \frac{\partial t}{\partial v}\,\delta v\;,$ (7)
$\displaystyle \delta x$ $\textstyle =$ $\displaystyle \displaystyle \frac{\partial x}{\partial v}\,\delta v\;.$ (8)

The uncertainty $\{\delta t,\delta x\}$ is the main output of our study. It is shown as small line segments in Figure 7 and as uncertainty in horizons in Figure 8. The estimated uncertainty varies inside the image space and generally increases with depth. It is surprisingly large, given the mild variations in structure and velocity. We believe that, when making quantitative estimates related to structural interpretation, it is important to take this kind of uncertainty into account.

When converting seismic images from time to depth, it is also important to realize that the time-to-depth conversion itself is a mathematically ill-posed problem (Cameron et al., 2007) and has its own significant uncertainties.


next up previous [pdf]

Next: Conclusions Up: Structural uncertainty of time-migrated Previous: Uncertainty in velocity picking

2013-12-07