Collapse loads 1 Evacuation during drilling
Collapse loads occurring during drilling are usually the result of borehole evacuation due to natural or induced losses. There are however other cases to be considered.
1.1. Internal pressure profile
In a losses situation, the mud column will drop until the pore pressure at section TD is just balanced by the pressure due to the mud column.
The evacuation level should always be the deepest that can occur and which gives the lowest evacuation level.
1.2. External pressure profile
The external pressure profile for collapse . . .