Page 152 - Formulas and Calculations for Petroleum Engineering

Drilling engineering formulas and calculations Chapter 2 145

2.167 Plug length to set a balanced cement plug

Input(s)
N s : Number of Sacks of Cement to be Used (stroke)
3
AC: Annular Capacity (ft /ft)
3
P c : Pipe or Tubing Capacity (ft /ft)
3
E: Original+extra Volume Req in Percentage (fraction) Y s :Yield of Slurry (ft /stroke)
Output(s)
L p : Length of Plug (stroke)

Formula(s)

N Y s
s
L ¼
p
AC E+ P
c
Reference: Lapeyrouse, N. J., 2002, Formulas and Calculations for Drilling, Production and Workover, Second Edition,
Gulf Professional Publishing, Page: 61.

2.168 Polar moment of inertia

Input(s)
4
J b : Polar Moment of Inertia of Pipe Body (ft )
4
J j : Polar Moment of Inertia of Tool Joint (ft )
L: Length of Pipe (ft)
l: Joint Tool Length (ft)

Output(s)
4
J p : Polar Moment of Inertia of Pipe (ft )

Formula(s)

J J
b j
p
J ¼
L l l
J J b
j
L L
Reference: Samuel. E Robello. 501 Solved Problems and Calculations for Drilling Operations. Sigma Quadrant. 2015.
Houston, Texas, Page: 356.

2.169 Polished rod horsepower—Sucker-rod pump
Input(s)

C: Calibration Constant of Dynamometer (lb/in.)
2
A: Upper Area of Card (in. )
L: Length of Card (in.)
S: Maximum Theoretical Polished Rod Position (in.)
N: Strokes Per Minute (spm)