Thus, the tower takes only the vertical load of the risers distributed along the height and not at the top. Wave induced fatigue loads on structures in the ocean are due to high sea state with waves of 3-7 second periods. This invention relates generally to offshore floating structures, and, more particularly to a tension-based tension leg platform (TBTLP) for use in ultra deepwater to support dry-tree oil and gas production which utilizes a tension base or artificial seabed to simplify tendon design at deep water locations in harsh environment and a truss pontoon to reduce vertical and horizontal wave loadings.
Of course environmental conditions are also key factors in the design of the TLP like any other offshore platforms. The tower is, thus, free from the horizontal loads and structural moments along the span. This embodiment introduces a riser support tower which is compliant to waves and is adequate to take the riser pretension along the length of the tower in its free standing position. 10. Several other installation methods could be obtained based on the past experiences gained from the TLP installation.
The total transport weight of the hull with deck and pay load is about 35,000 short tons as per Table 4. Such a low weight structure may be dry-transported by large transport barge in ocean voyage from the fabrication yard of one part of the world to the installation site of another part of the world. Installation of the riser support tower may be carried out efficiently with the risers inbuilt within each segment of the tower, utilizing conventional riser connection techniques to connect the risers between the tower bays. The horizontal motions of the hull and the tower are coupled to each other. The decoupling between the riser tower and TLP in the vertical and rotational mode of the oscillation and their coupling in the sway and surge modes create friendly motion behavior between the two structures without hurting each other. The benefit is the smaller dynamic tensions for the tendons that are utilized in extending the water depth application.
Dolor De Espalda
This configuration effectively increases the restoring effect of the tendons and thus reduces the column spacing requirements. The heave, pitch and surge natural periods are obtained for this design are shown in Table 4. The heave and pitch periods are 3.85 sec and 2.75 sec respectively. The coupled analysis with Morison type wave loading for the TLP columns and with the relative velocity drag damping wave forces for the tower member and the riser members may be obtained in a simplified way to study the combined behaviour of the TLP oscillation with the tower.
The present tension based tension leg platform (TBTLP) places an artificial seabed at a water depth of 4000 ft to support the 4000 ft water depth TLP, thereby extending capacity of the 4000 ft TLP to 8000 ft water depth. Variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art from this disclosure, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed in the following claims defining the present invention. While the present invention has been disclosed in various preferred forms, the specific embodiments thereof as disclosed and illustrated herein are considered as illustrative only of the principles of the invention and are not to be considered in a limiting sense in interpreting the claims.
Engineering challenges are being realized for 10,000 ft water depth and 10,000 psi internal pressure for the Gulf of Mexico ultra deepwater applications in the riser design. This enables the use of a TLP in ultra deepwater by controlling the natural period of the system by replacing the pontoons from the hull. The linear spring stiffness for the TLP heave, pitch and sway are given below. FIG. Dolor espalda estar de pie . 2 shows, schematically, the 2-D geometric displaced position of the conventional TLP in sway with pitch and set-down relationship. It is important to note that both the upper and the lower tendons are always retained in tension due to excess buoyancy of the TLP hull. The TBTLP uses a lateral resisting mooring system to the submerged base to reduce offsets due to underwater currents and horizontal forces resulting from the reactions of the upper tendons due to the TLP sway. FIG. 6 is a perspective view of a tension based tension leg platform (TBTLP) which utilizes a centrally located riser support tower; the artificial seabed tension base, truss pontoon, and truss extensions are not shown for purposes of clarity and to avoid confusion.
Dolor Espalda Media
A tension base for tension leg platforms is shown and described in my U.S. FIG. 5 is a perspective view of a tension based tension leg platform (TBTLP) which utilizes an artificial seabed at a water depth that enables a TLP to work technically and economically. FIG. 4 is a perspective view of a cantilever extended arm truss pontoon TLP.
Dolores Musculares Y Fiebre
Removing the pontoon from the conventional TLP provides several advantages. Dolor de la planta del pie derecho . Replacing the conventional shell pontoon with the submerged truss-pontoon reduces the added mass of the TBTLP hull and consequently the vertical and the horizontal forces on it. The reduction of vertical and horizontal wave forces reduces the heave and surge forces and the displacement. However, the TBTLP is a fixed structure, and the natural heave of the structure is determined with the tendon axial stiffness and added mass of the hull. However, the hull is inertia wave force dominated which is 90° out of phase with the drag forces. Attempts to achieve cost effective development have increased the deck facility and production capacity that result in larger deck load.
However, they are not yet practical from the standpoint of cost. However, the riser and the tendon design problems remain unsolved yet for a complete application of the system in deepwater. Wherein KB is the distance from the keel to the center of buoyancy and KG is the distance from the keel to the center of gravity (FIG. Thus, in a transport mode, the tension base box could be sized to carry the hull and deck in transportation draft as shown in FIG. 5. The hull is sized for 4000 ft water depth. The tower may be simplified with an equivalent beam column and the TLP may be modelled as a rigid structure with the calculated spring values. The slim riser tower is made of a welded steel frame structure with circular pipes Like horizontal conductor support frames, the riser tower has horizontal riser support frames at every interval of the design span.
Although several alternate dry-tree support vessels have been developed and used, the TLP is still a preferred candidate structure for many oil and gas companies. The riser top tension load is removed from the TLP design, making the hull slim and practical for the tendons. This significantly aids in extending the tendons to the deepwater. At water depths close to 5000 ft, the weight of the tendons becomes impractical.
The overall hull is cost effective for 8000 ft water depth and is less than 4000 ft water depths. Coronavirus dolor muscular . As discussed above, the conventional technology limits the TLP to water depths of 4000 ft. The artificial seabed box is provided with an open section for the purpose of well accesses by production risers. The same box is used for the construction of the columns in the shipyard to place the columns above and skid into the ocean. The box is also used for local dry transport of the hull with or without the deck as designed accordingly.
- Caminas con la espalda encorvada
- Otros relajantes musculares. Por ejemplo, la ciclobenzaprina
- Yogures o papillas de frutas que adquieren un rico sabor con almendras o avellanas molidas
- Pacientes con patologías asociadas
- Repite su uso 2 veces al día si lo consideras necesario
- Evita alimentos y medicamentos irritantes
Notably the horizontal offset due to the wave forces also reduced. Motion, wave loading, compliancy between the TLP and the tower, etc., also control the design depth of the tower. The riser tower is drag dominated and the TLP is wave inertia dominated design. Shell Oil Company had developed several of its deepwater oil fields with TLP technology in the Gulf of Mexico and is currently working on MARS TLP phase 2 with TLP concept in 3000 ft water depth. The Shell Ursa TLP uses 14.0 inch OD and 0.75 inch wall thickness and 10⅞ inch OD and 0.608 inch wall thickness production risers for the Gulf of Mexico 4000 ft water depth. The most attractive feature of the TLP is its application for dry-tree support in the production platform.