Page 155 - Formulas and Calculations for Petroleum Engineering

148 Formulas and calculations for petroleum engineering

2.175 Pressure required to break circulation—Annulus

Input(s)
2
y: Gel strength of drilling fluid (lb/100ft )
L: Length of Drill String (ft)
Dh: Diameter of hole (in.)
Dp: Diameter of drill pipe (in.)

Output(s)

P gs : Pressure to overcome mud’s gel strength inside annulus (psi)

Formula(s)

y
P ¼ L
gs
ð
300 Dh DpÞ
Reference: Formulas and Calculations for Drilling, Production and Workover, Second Edition, Lapeyrouse, Page: 79.

2.176 Pressure required to break circulation—Drill string

Input(s)
2
y: Gel Strength of drilling fluid (lb/100ft )
L: Length of Drill String (ft)
d: Inside diameter of drill pipe (in.)

Output(s)

P gs : Pressure to overcome mud’s gel strength inside drill string (psi)

Formula(s)

L
P ¼ y
gs
300 d
Reference: Formulas and Calculations for Drilling, Production and Workover, Second Edition, Lapeyrouse, Page: 79.

2.177 Pressure required to overcome gel strength of mud inside the drill string
Input(s)

2
y: Gel Strength of Drilling Fluid (lb/100 ft )
d: Inside Diameter of Drill Pipe (in.)
L: Length of Drill String (ft)

Output(s)

P m : Pressure Required (psi)