A combined underwater production support buoy and its integral installation and recovery method

Abstract

The invention discloses a combined type underwater production supporting buoy and an integral mounting and recycling method thereof. The buoy comprises outer-layer buoy bodies, inner-layer buoy bodies, peripheral cross braces, internal cross braces, guiding ring plates and limiting plates. The outer-layer buoy bodies are used for providing tensioning forces for mooring cables, the inner-layer buoy bodies are used for providing tightening and tensioning forces for rigid vertical tubes, and therefore, the underwater production supporting buoy can conveniently and respectively provide the required tightening and tensioning forces for the rigid vertical tubes and the required tightening and tensioning forces for the mooring cables. As long as the combined type underwater production supporting buoy is used in an ultra-deepwater ocean oil and gas engineering development system, requirements of practical application of engineering can be met. By vertical movement and stress decoupling of the rigid vertical tubes and the outer-layer buoy bodies, the stress and the motion amplitude of the rigid vertical tubes can be reduced, and the strength and the fatigue property of the rigid vertical tubes are improved. When the underwater production supporting buoy deviates, secondary distribution of the tightening and tensioning forces of the various rigid vertical tubes can be avoided, and therefore, the strength and the anti-fatigue performance of the rigid vertical tubes are improved.

Description

technical field [0001] The invention relates to an ultra-deep water offshore oil and gas engineering development system, in particular to a combined underwater production support buoy and its integral installation and recovery method. Background technique [0002] With the gradual depletion of oil and gas resources in the land, offshore and middle-deep seas, the exploitation of offshore oil is gradually moving towards the deep sea and ultra-deep sea. However, the existing floating production platforms and underwater production systems are difficult to apply in deep water and ultra-deep water environments. [0003] Chinese patent (CN 102434129 A) discloses an ultra-deep water offshore oil and gas engineering development system, which is used for oil and gas development in an ultra-deep sea environment with a water depth of more than 3000m. The system includes a surface floating production device, a standpipe support buoy, underwater oil production equipment, an upper flexibl...

AI Technical Summary

Problems solved by technology

Both mooring cables and rigid risers are passively tensioned by riser support buoys, so it is difficult to conveniently adjust the top tension of the two

Therefore, it is difficult for the above-mentioned riser support buoy to simultaneously provide the top tension force required by the mooring cables and the rigid riser;

[0007] 2. The burial depth of the riser support buoy must be large enough (below 200m water depth), if the burial depth is insufficient, the riser support buoy is susceptible to lateral deviation due to the influence of shallow water waves, which will cause mooring cables and rigid riser tops The secondary distribution of the tension force causes the main stress change of the rigid riser, which is not conducive to the strength and fatigue performance of the rigid riser;

[0008] 3. The riser support buoy is moored on the seabed with three mooring cables. When any one of the cables breaks and fails for some reason, the riser support buoy changes from three-point support to two-point support, resulting in loss of stability. The top tension force of the mooring rope and the rigid riser is redistributed, and the top tension force of the rigid riser increases sharply, and the excessive top tension force will break the rigid riser and cause the system to collapse;

[0009] 4. The mooring cable is connected to the end of the neutral buoyancy truss structure. Once the cable is tensioned, stress concentration will occur at the connection between the truss structure and the end of the cantilever buoy, which will affect the service life of the riser support buoy

[0010] Due to the above problems, the riser support buoys in the above systems are difficult to apply in engineering practice

Images