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Unformatted text preview: eliable casing
strings. Each operator may have his own set
of design factors, based on his experience,
and the condition of the pipe.
5 Casing Design
In PETE 411, we’ll use the design factors
recommended by the API unless otherwise
specified. These are the API design Factors:
Tension and Joint Strength:
NT = 1.8
Collapse (from external pressure): Nc= 1.125
Burst (from internal pressure):
Ni = 1.1
6 Casing Design
What this means is that, for example, if we
need to design a string where the maximum
tensile force is expected to be 100,000 lbf,
we select pipe that can handle 100,000 * 1.8
= 180,000 lbf in tension.
Note that the Halliburton Cementing Tables
list actual pipe strengths, without safety
factors built in.
7 Casing Design
Unless otherwise specified in a particular
problem, we shall also assume the following:
Worst Possible Conditions
1. For Collapse design, assume that the
casing is empty on the inside (p = 0 psig)
2. For Burst design, assume no “backup”
fluid on the outside of the casing (p = 0 psig)
8 Casing Design
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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