Stumped trying to calculate annular volume with multiple diameters

I am trying to calculate annular volume in a hole with varying diameters and with pipe inside that hole with varying diameters. For example:

Hole sizes:

Hole size #1: 20" diameter, top of hole: 0 ft, bottom of hole: 1,000 ft.
Hole size #2: 18" diameter, top of hole: 1,000 ft, bottom of hole: 2,000 ft.
Hole size #3: 16" diameter, top of hole: 2,000 ft, bottom of hole: 3,000 ft.
Hole size #4: 10" diameter, top of hole: 3,000 ft, bottom of hole: 4,000 ft.
Hole size #5: 8" diameter, top of hole: 4,000 ft, bottom of hole: 10,000 ft.

Pipe inside hole:

Pipe size #1: 14" diameter, top of pipe: 0 ft, bottom of pipe: 2,500 ft.
Pipe size #2: 9" diameter, top of pipe: 2,500 ft, bottom of pipe: 3,500 ft.
Pipe size #3: 6" diameter, top of pipe: 3,500 ft, bottom of pipe: 9,000 ft.

What I would like to be able to do is input a top depth and bottom depth and calculate the volume in between these 2 depths, so let's say, I need the annular volume from 1,500 ft to 9,000 ft.

I have thought about this problem for a long time and have come up short on solutions. I have tried using nested IF statements, but they get extremely long and complicated because both the hole size and pipe size are varying and occur at varying depths.

Ideally, I would like to put the hole sizes and depths into a table, the pipe sizes and depths into a table and be able to input the desired top and bottom calculation limits and it report back to me the volume between the limits.

This may be more easily achieved in visual basic, but I have little visual basic experience so would need a lot of help with visual basic. Any help you can provide or suggestions to get me going in the right direction would be greatly appreciated.

THANKS! Richy

Im not a mathematics guru, although Ive always enjoyed working on maths problems. It seems to me that you might be over-complicating things based on what you are saying. Im not sure why you have pipe lengths that are larger than your holes, but if we ignore that, then with a hole depth of 1000ft, diameter 20 inches and a pipe 14 inches in diameter, the annular volume is 1112.647398 cubic feet.
This is calculated as follows:

= PI() * (R^2 - r^2) * D
= PI() * (10^2 - 7^2) * 12000/12^3
= 1112.647398 cu ft.
All you need do is build a list of the outer and inner radii, with formula to calculate the area difference, and put in D as a multiplier to calculate the volume.