wellbore stability

1. 1
Wellbore Stability
1
“Insitu” Formation Forces
2

2. 2
Radial Force from a Hydrostatic Column
3
Hoop Stress
4

3. 3
Force Anisotropy in Deviated Wellbores
5
Mud Weight Window with Inclination
Mud Weight Schedule
Wellbore Collapse
Formation Fracture
6
Pore Pressure
p

4. 4
Wellbore Stability Drivers for Mud Weight
7
th
rue
Vertical
Dept
8
Tr

5. 5
pth
True
Vertical
Dep
9
T
Leak Off Test (LOT)
Surface Pressure + Hydrostatic Pressure
exceeds formation strength & rock fractures
10
Formation Integrity Test (FIT) applies
calculated Surface Pressure + Hydrostatic Pressure
to simulate Equivalent Mud Weight (EMW). EMW
designed to avoid rock fracture.