Pipe displacement, normally in bbl/ft, is steel volume to displace fluid volume. When we either pull out of hole or trip in hole for any kind of pipes such as drill pipe, casing or tubing, you should know how much fluid to displace steel volume.
For example, when we pull out of hole, a trip sheet must be monitored all time. We must know how much fluid will fill the hole each stand of drill pipe pulled out. If the volume of displacement less than theoretical displacement value, we may have problem due to swabbing formation into wellbore.
This post will demonstrate how to calculate plain pipe displacement with this following formula:
Pipe Displacement in bbl/ft = (OD in2 – ID in2 ) ÷ 1029.4
OD is out side diameter of pipe in inch.
ID is inside diameter of pipe in inch.
This formula is good for plain pipe diplacment such as casing and tubing. It is not for closed-end displacement. It’s not accurate enough for drill pipe because this formula does not account for tool joint displacement therefore you need drill pipe specification sheet for its displacement.
Example: Determine pipe displacement in bbl/ft of 9-5/8” casing 40 ppf, OD = 9.625 in, ID = 8.835 in
Pipe Displacement of 9-5/8” casing 40 ppf in bbl/ft = (9.6252 – 8.8352 ) ÷1029.4
Pipe Displacement of 9-5/8” casing 40 ppf in bbl/ft = 0.01417 bbl/ft
Ref books: Lapeyrouse, N.J., 2002. Formulas and calculations for drilling, production and workover, Boston: Gulf Professional publishing.
Bourgoyne, A.J.T., Chenevert , M.E. & Millheim, K.K., 1986. SPE Textbook Series, Volume 2: Applied Drilling Engineering, Society of Petroleum Engineers.
Mitchell, R.F., Miska, S. & Aadny, B.S., 2011. Fundamentals of drilling engineering, Richardson, TX: Society of Petroleum Engineers.