Page 174 - Formulas and Calculations for Petroleum Engineering

Drilling engineering formulas and calculations Chapter 2 167

2.222 Upward force acting at the bottom of the casing shoe

Input(s)
2
A: Area Below Casing Shoe (in. )
∂P: Differential Pressure B/w Cement and Mud (psi)

Output(s)
F u : Upward Force (lb)

Formula(s)

F ¼ A ∂P
u
Reference: Lapeyrouse, N. J., 2002, Formulas and Calculations for Drilling, Production and Workover, Second Edition,
Gulf Professional Publishing, Page: 67.

2.223 Vertical curvature for deviated wells

Input(s)
I a : Original Hole Inclination (degree)
I b : Desired Hole Inclination (degree)
∂L: Course Length (ft)

Output(s)

VC: Vertical Curvature (degree/ft)

Formula(s)

100
VC ¼ I I Þ
ð
b a
∂L
Reference: Samuel. E Robello. 501 Solved Problems and Calculations for Drilling Operations. Sigma Quadrant. 2015.
Houston, Texas, Page: 84.

2.224 Viscous shear stress at the outer mudcake boundary

Input(s)
R c : Radius from the Center of Drillpipe to the beginning of Mudcake (in.)
R p : Radius from the Center to the Inner Boundary of the Drillpipe (in.)
v z : Axial Velocity Parallel to the Wellbore Axis (in/s)
x f : Transient Invasion Front (in.)
x f,o : Initial Displacement, i.e., Spurt (in.)
dp : Pressure change with Z direction that is parallel to the Wellbore Axis (psi/in.)
dz
m: Viscosity (cP)

Output(s)
2
τ (Rc) : Viscous Shear Stress at the outer Mudcake boundary (lb/in. )