Slug Weight Calculation for Length of Dry Pipe

There are 3 steps in calculating slug weight ppg for a length of dry pipe.

1. Find length of slug in drill pipe feet -

Slug length feet = slug volume bbls / drill pipe capacity bbls/ft

2. Find Hydrostatic Pressure required for slug drop in drill pipe -

Hydrostatic Pressure psi = MW ppg x .052 x dry pipe in feet

3. Find the slug weight in ppg -

Slug weight ppg = HP psi / .052 / slug length in ft + MW ppg
Now that we know how to calculate slug weight in ppg, let’s do an example

given the following data:

- Desired length dry pipe (3 stands) = 276 feet

- Mud Weight = 12.5 ppg

- Drill pipe capacity (4.5 in) = 0.01422 bbls/ft

- Slug volume = 38 bbls

1. Slug length feet = 38 bbls / 0.01422 bbls/ft

= 2672.29 bbls/ft

2. Hydrostatic Pressure psi = 12.5 ppg x .052 x 276 feet

= 179.40 psi

3. Slug weight ppg = 179.40 psi / .052 / 2672.29 ft + 12.5 ppg

= 13.8 ppg