Method and apparatus to stabilize a columnar platform for deepwater offshore applications. An added mass stabilizer system is utilized to control first order heave, pitch, roll, surge and sway motions of the floating platform. The stabilizer is suspended beneath the platform by a set of tendons a sufficient distance to (1) enter a quiescent zone beneath the action of waves and currents, (2) provide a sufficiently long movement arm to resist pitch and roll torquing, and (3) incorporate sufficient flexibility into the suspension system to avoid shock loads. The stabilizer is sized to (a) provide sufficient submerged weight to maintain the tendons in constant tension and, (b) create adequate added mass (actual stabilizer weight plus mass of water moved by the stabilizer) to provide the desired control of first order motions. A secondary mooring system such as a spring-buoy mooring or dynamic positioning system can be provided to control drift produced by higher order motions and first order yaw.
A floating system for very deep water includes a floating structure (1) subject to the external loadings (7, 8, 9) inducing stresses, the floating structure (1) being held in position on the sea bed by one or several tensioned lines (2) made of a material having given mechanical properties. The tensioned line or lines (2) are made of a material that is not very sensitive to fatigue stresses and the tensioned line or lines are sized in a manner independent of the fatigue phenomena associated with the dynamic behavior of the floating system under the effect of external loadings.
A riser and tendon management system for offshore hydrocarbon production facilities has a data acquisition system with instrumentation suitable for gathering all necessary information concerning the immediate condition of the facility and a riser and tendon analysis system for comparing actual with ideal conditions for the facility. Information is generated as to what corrective action must be taken. The analysis system stores past corrective actions and results and factors this information into the current suggestion for correction thereby reducing riser and tendon stress while increasing their fatigue life.
A semi-submersible production platform (10) intended for oil production, water injection and oil and gas export includes a hull (11) of basic rectilinear shape consisting of floats (17) with rectangular cross-section forming a closed square ring (12). Four columns (13) of square section are located, one in each vertex, of the closed square ring (12). A risers receipt system (14) consists of lateral supports (15) and connectors of square section (16). A passive anchoring system (19) is provided along with a truss-shaped deck structure (23), an equipment arrangement (24) with full seggregation of process equipment, utilities and quarters. A water intake (25) system at large depths has an intake pipe (26) connected at the top to the float (17) through a flexible coupling (27).
A system and method for the offshore transfer of liquefied natural gas from an LNG tanker vessel to a moored or dynamically positioned regasification plant is disclosed. Once the state of the natural gas has been changed from liquid to gas or regasified, the natural gas is conveyed to another location in a gaseous state.
The present invention relates to an apparatus and methods for coupling objects that are displaced from one another. In particular, the present invention relates to an apparatus and methods for providing a connection member, for coupling objects that are displaced from one another, that is able to adapt to changing operating conditions. The connection member is a composite tubular that responds to pressure changes such that when the internal pressure of the composite tubular is changed, the length of the tubular proportionally changes, thereby enabling the composite tubular to do useful work.
