Page 120 - Formulas and Calculations for Petroleum Engineering

Drilling engineering formulas and calculations Chapter 2 113

2.88 Friction factor in drill pipe

Input(s)
m s : Static Viscosity (cP)
s: Normal Stess at Contact (psi)
k: Exponential Constant (dimensionless)
t: Average Contact Time (s)
V t : Trip Speed (ft/s)
o: Angular Speed (ft/s)

Output(s)
m: Constant (dimensionless)

Formula(s)

m s
m ¼
0
2 2
0:5 1
m s V + o
s
t
1+ @ A
k t
Reference: Samuel. E Robello. 501 Solved Problems and Calculations for Drilling Operations. Sigma Quadrant. 2015.
Houston, Texas, Page: 375.

2.89 Front displacement of a particle in the reservoir—Formation invasion
Input(s)

x o : Initial Marked Position (ft)
k: Permeability (mD)
m: Viscosity (cP)
Ø: Porosity (fraction)
P r : Constant "Reservoir" Pressure at x¼L (psi)
P l : Pressure at x¼0 location (psi)
t: time (days)
L: Length (ft)

Output(s)

x(t): Front Displacement of an Initially Marked Particle in the Reservoir (ft)

Formula(s)

k ð P P Þt
r
l
xtðÞ ¼ x mØ L
o
Reference: Chin, W. C. (1995). Formation Invasion, Page: 30.