Page 98 - Formulas and Calculations for Petroleum Engineering

Drilling engineering formulas and calculations Chapter 2 91

Formula(s)

ð
C +C +C +T +T +T Þ C +C +C Þ
ð
r
b
t
s
to
t
c
m
d
C ¼
d
F T d
Reference: Samuel. E Robello. 501 Solved Problems and Calculations for Drilling Operations. Sigma Quadrant. 2015.
Houston, Texas, Page: 468.
2.38 Cost per foot of coring
Input(s)
C b : Core Bit Cost ($)
C: Rig Cost ($)
T d : Total Coring Time (h)
T t : Trip Time (h)
T r : Core Recovery Time (h)
F: Footage Cored (ft)
R c : Core Recovery Percentage (fraction)

Output(s)
C: Cost per Foot of Coring ($/ft)

Formula(s)

C +C T +T +T Þ
ð
b
t
d
r
r
C ¼
F R
c
Reference: Samuel. E Robello. 501 Solved Problems and Calculations for Drilling Operations. Sigma Quadrant. 2015.
Houston, Texas, Page: 469.
2.39 Critical annular velocity and critical flow rate
Input(s)

y600: 600 Viscometer Dial Reading (dimensionless)
y300: 300 Viscometer Dial Reading (dimensionless)
Dh: Diameter of Hole (in.)
Dp: Diameter of Drill Pipe (in.)
MW: Mud Weight in Use (ppg)

Output(s)

n: Power Constant (dimensionless)
K: Constant (dimensionless)
x: Constant (dimensionless)
AVc: Critical Annular Velocity (ppg)
GPMc: Critical Flow Rate (ppg)