Page 126 - Formulas and Calculations for Petroleum Engineering

Drilling engineering formulas and calculations Chapter 2 119

2.101 Hydrostatic pulling wet pipe out of the hole

Input(s)
NS: Number of Stands Pulled (number)
Lavg: Average length per stand (ft)
mw: Mud Weight (ppg)
cc: Casing Capacity (bbl/ft)
pd: Pipe disp. (bbl/ft)
pc: Pipe capacity. (bbl/ft)

Output(s)
BD: Barrel Displaced (bbl)
HP: Hydrostatic Pressure Decrease (Pulling Wet Pipe out of the Hole) (psi)

Formula(s)

BD ¼ NS Lavg pd + pcÞ
ð
mw
HP ¼ BD 0:052
cc pd + pcÞ
ð
Reference: Formulas and Calculations for Drilling, Production and Workover, Second Edition, Lapeyrouse, Page: 21.

2.102 Hydrostatic pressure in annulus due to slug

Input(s)
V a : Volume of Annulus (ft/bbl)
V s : Volume of Slug (bbl)
W s : Slug Weight (ppg)
W m : Mud Weight (ppg)

Output(s)
P: Hydrostatic Pressure (psi)

Formula(s)

P ¼ V V W W Þ 0:052
ð
a s s m
Reference: Lapeyrouse, N. J., 2002, Formulas and Calculations for Drilling, Production and Workover, Second Edition,
Gulf Professional Publishing, Page: 36.

2.103 Hydrostatic pressure decrease at total depth caused by gas-cut mud

Input(s)

MG: Mud Gradient (psi/ft)
C: Annular Volume (bbl/ft)
V: Pit Gain (bbl)