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20.12 Travelling Cylinder Plot
The travelling cylinder plot was invented by John Thorogood in the 1980s and is an excellent 2D representation of the proximity of other wells to planned trajectory.
20.12.1 Reading the Traveling Cylinder Plot These plots were used regularly in the days before computers and 3D visualization software. They are still used on many rig sites where 3D visualization is unavailable. Following the examples and text below should enable you to read and understand traveling cylinder plots. Consider these screens like a radar scan when travelling down the planned trajectory.
This scan shows the basic radar screen out to a range of 250 ft. Our well passes to the left of the red well, beneath and to the right of the green well and over the top of the blue well. At their closest points the red well comes within 120 ft., the green well comes within 70 ft. and the blue well within 30 ft.
Figure 96: Traveling Cylinder Plot - basic.
It is useful then to include marker points on the object wells for each MD in our well at some reasonable interval. This shows us where that well will be relative to us when we reach that depth.
Figure 97: Traveling Cylinder Plot – with marker points.
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