Time to Depth Conversions
Straight
ray depth is: Straight ray depth is easy to calculate but is NOT the correct way to calculate depth. Unfortunately, this conversion is still in common use. Depths predicted by this method will be too deep by several hundred feet in a 5000 foot well. You can compute it if you want to, but DON'T USE IT. Interval
velocity (as derived previously) is: Interval
thickness is: True
depth with curved ray path is: And
the average velocity is: The straight ray depth is always deeper (larger value) than the true depth, so this simplification should not be used for time to depth conversions. A typical graphical display of this kind of data is shown below.


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