Page 123 - Practical Well Planning and Drilling Manual

Section 1 revised 11/00/bc 1/17/01 2:56 PM Page 99

1.4.24
Casing Design [ ]

Table 1-1 Casing Design Criteria—Conductor

Drilling Criteria Production Criteria

Burst Resist a pressure at the shoe of
1 psi/ft with a gas gradient to
surface (0.1 psi/ft inside). Maximum
burst at surface; depth (ft) x 0.9 psi/ft.

Collapse Resist a normal external pressure
(0.465 psi/ft) with the conductor
evacuated (0.1 psi/ft inside). Maximum
collapse at shoe; depth (ft) x 0.365 psi.

Tension Weight of conductor in air plus
overpull allowance of 200,000 lbs.
Safety factor 1.1.

Compression Withstand loads of subsequent
casings, completion, wellhead, and
BOP. Use a safety factor of 1.0 with
the tensile minimum yield strength.

Buckling Long, freestanding conductor;
commission full engineering
buckling analysis.

Other 1. Resist driving forces if driven. Offshore; corrosion
Check that the planned connections protection in the
are suitable for driving. splash zone.
2. Set deep enough to allow returns
to the flowline, except on floating
rig where the next section drilled
with returns to seabed.

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