As discussed above, one of the problems in extending TLP technology to ultra deepwater applications is that the TLP is sensitive to topside deck load because it loses its pretension capacity with respect to the topside weight for the given hull buoyancy. The axial and the rotational spring stiffness values are very large resulting with large natural frequencies in heave and pitch modes for the TLP hull. Once the tower is fabricated by sections and then transported to the offshore location, the installation of the tower is carried out by telescoping the tower sections one after another through the center opening of the deck. The hull can also be towed to the site in a free floating position with the help of the tension base.
- Sensación de saciedad con pocas cantidades
- Necrosis de la piel y
- Colocar una pelota mediana entre los pies
- For optimized device=38.5 m2/2.01 m2=19.2
- Medir la presión de líquido en el conducto raquídeo
- Una psique extraconsciente con contenidos de carácter personal
9. At the installation site, the tension base box is flooded slowly and lowered to the submerged position at the designed water depth. The details and sequence of tower installation is shown in FIG. Drag damping due to the small diameter horizontal truss frame is effective at the vertical heave resonance. A TLP tendon requirement to keep the vessel concept effective within the practical cost budget is limited by the water depth. 1 is perspective view of a conventional tension leg platform (TLP) of the prior art.
Dolor De Hombro
FIG. 9 is a perspective view of a tension based tension leg platform (TBTLP) supported on the tension base box in a transport mode. In the transport condition, the box is buoyant with the inlet and outlet valves closed. Although the TLP looks like a floating vessel, in the operational mode, it behaves like a fixed structure in the heave, roll and pitch motions and thus enables support of a conventional dry-tree production system.
The practical depth limits of conventional TLPs with steel tendons a well known problem in the industry. Several alternatives had been proposed utilizing composite materials instead of steel for the tendons which may provide weight savings. Remedios caseros para el dolor de rodilla por artrosis . Each riser is supported with additional distributed buoyancy along the riser length, for example by clamping the risers to the tower to transfer loads. FIG. 8 is a schematic side elevation view of a modification of the TBTLP with a shorter semi-submerged riser support tower wherein top tensioned hydraulic cylinders supported by the TLP top deck top. FIG. 7 is a schematic side elevation view of a TBTLP with a shorter semi-submerged riser support tower. FIG. 7 shows, somewhat schematically, a schematic side elevation view of a TBTLP with a shorter semi-submerged riser support tower.
The riser support tower is very practical and solves the real world riser problem. 11. This is a very unique and most reliable installation procedure specially developed for the TLP concept. The hull and the tendon size are very reasonable for this design and for this water depth. That is within the energy region of the ocean environment to excite the tendons to the vertical resonance and causes serious fatigue problems to the tendons life. The pontoon extensions also significantly reduce the fatigue loading and the pretension requirement on the tendons and enhance the water depth capacity. The tension base provides and artificial seabed for the TLP, and the tendon support system is feasible in 8,000 ft water depths. The degree of excess buoyancy required for the tower is lower compared to the TLP hull. Thus, the fatigue load on the open truss bridge structure is not a serious problem in this design.
There are four main legs to the tower with diameters of 50″ to 70″ depending upon the design. The present invention introduces innovative technologies to enhance TLP applications in water depths of over 8000 ft. In water depths of 8000 ft with high pressure and high temperature (HP/HT) applications, the riser weight is large thereby increasing the hull size. The shorter tower structure is very simple; installation is easy and more compliant to waves and the TLP for better coupling effect. 3, in order to achieve the above three goals, first a modified truss pontoon type hull is used in the present tension-based tension leg platform, for example, a truss pontoon type hull as shown and described in my U.S. Consequently, the sway period and amplitude of the surface TLP are dramatically less compared to a conventional TLP. The tower is divided into a number of small sections.
Assume that the heave natural period of the conventional TLP is close to 5 sec.
The tower sections are added one-by-one using a crane and telescoped downwards to the seabed. Dolor de estomago y espalda lado derecho . In the diagram, To is the tether pretension and ΔT is the dynamic variation component of the tether tension. That makes the artificial seabed behave like the actual seabed. Assume that the heave natural period of the conventional TLP is close to 5 sec. The industry takes no risk in using this technology because several technical issues had been solved in the real world. Many wells have been abandoned because the cost-effectiveness to fix them in the deep water with subsea wells. The TBTLP wave offset, set-down, and consequently the tendon slacking effect are reduced to a much greater extent. FIG. 3 is a perspective view of a modified TLP with a generally C-shaped hull and truss pontoons. The purpose of the riser support tower is not only to move the riser weight out of the hull size but also to solve the riser design problems in the ultra deepwater environment with high pressure/high temperature (HP/HT) requirements.
The riser support-tower is allowed to move independently with respect to the TLP hull in the vertical direction. The pontoon extensions move the tendon connection point outboard of the columns by say 20 m (65 ft) to 25 m (82 ft) from the center of the square column. Dolor bajo de la espalda . The risers are supported laterally along the length of the tower at every span of spacing of the horizontal bracing of the tower. Alternatively, the shorter tower may have a length designed just to take care of the riser weight such that the buoyancy is distributed without extending all the way to the seabed. In the cases of the heave/pitch/roll, the effect of the riser support tower is neglected. The top TLP which is mounted on top of the artificial seabed sways about the pivot at the artificial seabed at 4000 ft instead of the actual seabed at 8000 ft.
Dolor En El Hombro
The purpose of the artificial seabed is to provide vertical and horizontal resistance to the tension leg tendons that are mounted on top. The tower is sized with shorter depth and has distributed buoyancy to take the 21,000 tons of riser vertical load. As discussed above, the purpose of the riser support tower is to shoulder the riser weight along the length of the tower with distributed buoyancy.
If the size of the square column side is based on the total displacement required to meet the conditions as per Table 1, then the TBTLP hull sizing is simplified compared to the conventional pontoon type TLP. When the platform heaves due to the wave forces, the artificial seabed resists vertically with the large added mass of the column of water standing above the vertical area of the base. If the riser load could be moved out from the shoulder of the hull, then the TLP may be smaller. It should be noted that the riser pretension, the SCR and the umbilical down preloads exceed deck payload by 1.6 times in ultra deepwater. This ensures the riser integrity in 8000 ft water depth service without slack.