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Unformatted text preview: * design factor
= 0.052 * 12.5 * 8,000 * 1.125
Pc = 5,850 psi ← req' d at the bottom.
Further up the hole the collapse requirements
are less severe
12 Casing Design
Req’d: Burst: 6,600 psi Collapse: 5,850 psi 13 Casing Design
Note that two of the weights of N-80 casing
meet the burst requirements, but only the
53.5 #/ft pipe can handle the collapse
requirement at the bottom of the hole (5,850
The 53.5 #/ft pipe could probably run all the
way to the surface (would still have to check
tension), but there may be a lower cost
14 To what depth might we
be able to run N-80, 47
#/ft? The maximum
annular pressure that this
pipe may be exposed to,
is: Depth Casing Design Pressure Collapse pressure of pipe 4,760
= 4,231 psi
15 Casing Design
At what depth do we see this pressure (4,231
psig) in a column of 12.5 #/gal mud?
Pc = 0 .052 * 12 .5 * h 1
4 , 231
∴ h1 =
= 6 ,509 ft
0 . 052 * 12 . 5 0 . 052 * 12 . 5
16 Casing Design
This is the depth to which the pipe
could be run if there were
no axial stress in the pipe… 6,509’
8,000’ But at 6,509’ we have (...
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This note was uploaded on 12/03/2012 for the course PMRE PMRE6004 taught by Professor M.tamim during the Summer '12 term at Bangladesh University of Eng and Tech.
- Summer '12