Flotation riser

Patent · Tue Mar 03 04:00:00 EST 1987

OSTI ID:6738814

Bartholomew, R E; Pettus, R G; Schnitzer, E; Fisher, E A

A flotation riser is described comprising a series of annular housings being interconnected to form buoyancy chambers surrounding an open central bore, means for connecting the lower of the housings to a subsea location, means for supporting the upper of the housings from a floating structure, a free-standing tubular string extending through the central bore of the series of housings with connection therebetween only at the lower and upper ends thereof, and having an external diameter sightly smaller than the internal diameter of the central bore and to allow relative freedom of axial movement therebetween, and means supplying a gas to the chambers to provide each of the chambers with a preselected amount of buoyancy. The method is described of providing an emergency deballasting system for a flotation riser having a plurality of flotation chambers including the steps of supplying gas to a plurality of the lower of the flotation chambers, retaining gas in the plurality of lower chambers as an emergency source of deballasting gas, and remotely releasing gas from the plurality of lower chambers into the chambers above them to deballast the chambers under emergency conditions and provide sufficient buoyancy to maintain the flotation riser in a substantially vertical position above its connection to a subsea wellhead when its upper end is free of all connections.

• Assignee: Cameron Iron Works, Inc., Houston, TX
• Patent Number(s): US 4646840
• OSTI ID: 6738814
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
03 NATURAL GAS
030300 -- Natural Gas-- Drilling
Production
& Processing
42 ENGINEERING
423000 -- Engineering-- Marine Engineering-- (1980-)
CONDUCTOR DEVICES
CONNECTORS
DESIGN
DRILL PIPES
DRILLING EQUIPMENT
ELECTRICAL EQUIPMENT
EQUIPMENT
FLUID FLOW
GAS FLOW
MARINE RISERS
MECHANICAL STRUCTURES
NATURAL GAS WELLS
OIL WELLS
OPERATION
PIPES
SUPPORTS
WELLHEADS
WELLS