Page 142 - Formulas and Calculations for Petroleum Engineering

Drilling engineering formulas and calculations Chapter 2 135

2
g c : Gravitational System Conversion Constant (32.17 (lbm/ft)/(lbf/s ))
2
g: Acceleration of Gravity (ft/s )
Z 1 , Z 2 : Fluid elevation at Positions 1 and 2 (ft)
v 1 , v 2 : Fluid velocity at Positions 1 and 2 (ft/s)
E l : Irreversible Energy Loss between Positions 1 and 2 (ft lbf/lbm)

Output(s)
W: Work done by the Fluid while in Flow (ft lbf/lbm)

Formula(s)

" #

dp g f 2 1
Z 2 2
P 2 r v v
W ¼ + ð Z Z Þ + + E l
2
1
g 2g
P 1 r f c c
Reference: Watson, D., Brittenham, T., & Moore, P. L. (2003). Advanced Well Control (Vol. 10). Society of Petroleum
Engineers, Page: 8.
2.143 Mechanical specific energy
Input(s)
WOB: Weight on Bit (lbf)
2
A b : Area of Bit (in. )
N: Rotational Speed of Bit (in./m)
T: Torque of Bit (lbf in.)
ROP: Rate of Penetration (m/in.)

Output(s)
2
MSE: Mechanical Specific Energy (lbf/in. )

Formula(s)

WOB 120 p N T
MSE ¼ +
A b A ROP
b
Reference: Samuel. E Robello. 501 Solved Problems and Calculations for Drilling Operations. Sigma Quadrant. 2015.
Houston, Texas, Page: 414.

2.144 Mud rheology—Herschel and Buckley law

Input(s)
2
τ y : Yield Stress (lb/100 ft )
2
K: Consistency Index (lb/100 ft )
g: Shear Rate (1/s)
n: Power Law Index, Slope of Plot Between Log Shear Stress and Log Shear Rate (dimensionless)

Output(s)
2
τ: Shear Stress (lb/100 ft )