Deepwater drilling in the Gulf of Mexico
A large independent leaseholder in the deep waters of the Gulf of Mexico
uses a hub and spoke system of drilling and production facilities to bring
discoveries on production quickly and cost effectively. Two safety valve
systems were installed at a total setting depth of 3,808 m [12,494 ft] in water
2,438 m [8,000 ft] deep and with well production pressures estimated at 68.95
MPa [10,000 psi].
Searching for a reliable safety valve system that would meet all well,
personnel, and environmental protection regulations in these extreme operating
conditions, the operator selected the Schlumberger TRC-II safety valve because
of its highly successful track record. TRC-II valves are
reduced-operating-pressure valves that perform effectively at depths where
other technologies do not.
Safety system tailored to deepwater well conditions
A 4.5-in TRC-II 10-series valve was installed April 2006 at a setting
depth of 3,808 m [12,494 ft]. A similar valve was installed the following
month. Both valves used 50-MPa [7,300-psi] gas spring system pressure.
TRC-II valves have redundant hydraulic actuation with integral-control
fluid filters and debris-insensitive disconnect-type rod pistons for fail-safe
operation. These valves also feature rod-piston actuators insensitive to tubing
pressure and a rugged flapper-closure system with a leakage-acceptance
criterion substantially more stringent than that required by API and ISO
specifications.
