Is it possible to add cells summing from the bottom upwards in a column?

[Scratch]

I need some help in working out a problem.

I need to work out the hang off point for drill pipe on an oil rig!

To do this I must sum a column of numbers....but sum them from the bottom summing upwards. It must then stop summing just prior to exceeding a pre-determined number that is located in another cell.

Any help would be greatly appreciated

Cheers

[martindwilson]

you could reverse the column then sum down conditionally then take the max

[Scratch]

I need to calculate info on a running tally so I don't know how to make that work. Basically every line will need to be recalculated, not just the overall total of the column. If I reversed the column, would there be a way to pick out the new cell that I need each time?

[martindwilson]

????? where would you add to?

[Scratch]

Okay...

Column A will be individually listed lengths of drill pipe

Column B will be the cumulative length of the drill pipe.

In one cell there will be the subsea depth of our hang off rams. This is the depth that the drill pipe will hang off below sea level. The drill pipe must hang off at one of the connections (hence the importance of the different lengths in column A)

If you can imagine that in order to hang off the pipe you would obviously have pick the drill pipe up off the bottom of the sell so you must calculate the drillpipe connection that is just below the hang off ram point. (the drill string must be picked up to that point)

Then it must be calculated all the way back to surface so that the driller can accurately see how far the top connection "sticks up".

Basically you have your total depth (cumulative), you can then subtract your hang off depth, but now you have to reference the tally (cumulative) and find the depth/connection that is just below the hang off point. The distance between the two is how far you must pick the drill string up. Then you must determine the distance between the connection that is hung off and the top of the entire drill string.

I'm not sure if this makes any sense or not....I really appreciate any help you can offer

Cheers

[martindwilson]

nope no sense at all! mock up a workbook showing the layout and some results you'd like to see