James G. Speight, in Subsea and Deepwater Oil and Gas Science and Technology, 2015. Compliant structures, e.g., the guyed tower and tension-leg platform, are being developed; they can extend production capabilities to water depths of 600 meters, and possibly beyond. This type of rig structure can be configured to adapt to existing fabrication and installation equipment. Exxon in 1983 installed the first guyed tower named Lena Guyed tower in the Mississippi Canyon Block in 1000 ft (300 m) water depth. An essential component of a tilt-up system is the “gin pole” or a fixed section to use as a lever arm to provide leverage to lift the tower weight. The multi-deck topsides are approximately 210-by-140 ft and hold 21 well slots, and the entire structure weighs around 43,000 tons. But unlike in sea star, the tension legs dont go all the way to the sea floor. HCP uses a relatively smaller size TLP and manageable size sections of a smaller size compliant tower. Shell Oil is the operator of the project with 45.39%. The guylines typically have several segments. Tower types commonly used in UHVDC transmission lines can be classified into guyed towers and self-supporting towers (as shown in Fig. A guyed tower, and a tension leg platform are popular compliant struc- The jacket of a compliant tower has smaller dimensions than those of a fixed platform. A deep compliant tower Petronius, Gulf of Mexico, USA. Tilt-up systems have been used for both lattice and monopole towers, but is typically used for monopole towers. A double-circuit tower usually has three or four cross-arms arranged in an umbrella or drum form and can significantly narrow the line corridors by arranging the three-phase conductors vertically. We began our work in the western Gulf, where we visited the Baldpate and Jolliet platforms. 9. Other types of platforms like guyed towers, tension legs, semisubmersibles, floating structures, etc. The portion of the tower that contains the production and crew quarter modules is the surface facility. The upper part is a lead cable, which acts as a stiff spring in moderate seas. tension leg platforms), but compliant towers still demonstrate static stability albeit with greater degrees of lateral deformation (up to 2.5%) compared to land-based structures (usually 0.5% or less). Compared with floating systems, such as tension-leg platforms and SPARs, the production risers are conventional and are subjected to less structural demands and flexing. The structure is held in a fixed position by tensioned tendons, which provide for use of the TLP in a broad water depth range up to about 2000 m. During more extreme weather conditions, the guy wires are designed to lift the clump weights off the bottom, and the clump weights create a larger restoring force to resist the larger wave forces. 7.18). Tension-leg platform. Tension leg platforms installed as of 2002 . But they use narrower towers of concrete and steel. 1.5.3 Passive Control Algorithm 26. Subrata Chakrabarti, ... Cuneyt Capanoglu, in Handbook of Offshore Engineering, 2005. The towers are all high-strength steel tubular towers whose main legs are made of SS55 steel tubes or STK55 section steels and secondary members are made of SS41 angle steels or STK41 section steels. A 1150-kV suspension cable tangent tower. Single-circuit self-supporting tower. Compliant Platform Guyed tower platform Tension Leg Platform (TLP) The relatively light weight jacket of a guyed-tower platform … Due to this the platform experiences more horizontal motion due to the jerks from the rough weather. Yet to be installed are the first full–scale tension–leg (TLP) and guyed–tower types of installations. Compliant tower † Compliant Tower † Guyed Tower † Articulated Tower † Tension Leg Platform 3. Exxon is further researching use of this type of platform in water depths to 5,000 feet. Because guyed towers need guy wires, they are usable only in plains areas or hilly areas. A guyed tower consumes less steel but occupies a large area. Figure 7.25. Large barge-mounted cranes position and secure the jacket and install the surface facility modules. 7.17 shows a 1000-kV V-shaped guyed tower designed in Italy. It is one of the world's tallest structures. The tower is installed in the middle opening of the four leg TLP. Compliant Platform Using rigid platform in water much over 1000 feet depth is not practical – very much expensive to build. Guyed towers feature simple tower type, easy construction, and smaller weight of single tower which can reduce steel consumption and construction costs, and they are mostly used in areas where operation and maintenance are convenient, such as shallow hills and deserts. Compliant Towers, Tension Leg Platforms, Spars, Subsea Systems, Floating Production Systems, and Floating Production, Storage and Offloading Systems are now being used in water depths exceeding 1,500 feet. Remotely operated sea floor production systems have been designed for very deep waters (beyond 600 meters). Figure 8.6. The tower was placed in 1000 ft of water and utilized 20 galvanized spiral wound steel wire ropes as guy lines with 179-ton clump weights placed in a symmetrical pattern around the platform. 1.3 Guyed Tower and Articulated Tower 19. However, Conoco has contracted for the design and construction of a TLP for the Hutton field in the North Sea. These structures are much lighter and cost considerably less. Figures 8.1 and 8.2 show a cat-head tower and cup tower, respectively. The following compliant structures will be discussed: articulated loading platform (ALP) or tower (ALT), guyed tower, tension leg platform (TLP), and spar platform Conventional drilling and production platforms have been installed to water depths of 300 meters. A stiff arm or gin pole is used as a lever to lift the tower [7]. Guyed towers can be adapted for erection using a tilt-up system. Compliant-tower rigs are similar to fixed platforms, ... Tension-Leg Platform . A small wind turbine can be lifted into place at the top of the tower with the same assembly device. Document handling and procedures applicable to engineering office are also the same. Figure 7.27. 7.23 shows a self-supporting cup tower with three V-shaped insulator strings designed in Italy. In Japan, UHV AC transmission lines use double-circuit towers which typically have three or four layers of cross-arms supporting conductors vertically (as shown in Figs. This platform allows drilling at an amazing depth of 7000 feet. Figure 7.26. An increase of temperature difference of 1°C results in an increase in efficiency of approximately 10%. The articulated tower is considered as amplification of tension leg platform. The primary objection to such articulated systems arises as a result of the tower's lack of redundancy and the difficulty of inspection and/or replacement of the articulated joint. Figure 8.7. In 1150-kV single-circuit transmission lines constructed by the former Soviet Union, the cost of towers and foundations accounted for 31% of the total construction cost, and steel consumed by towers for each kilometer of lines was 68. FUNCTIONAL SCHEMATIC OF A TYPICAL TLP 30. Compared with guyed towers, they have such advantages as smaller footprint, easy construction, and convenient operation and maintenance. The platform is permanently moored by means of tethers or tendons grouped at each of the structure’s corners. These towers function on the basic idea of fixed platforms. Copyright © 2021 Elsevier B.V. or its licensors or contributors. Tension leg platform. Similarly, the guyed–tower is designed to minimize support requirements and therefore to operate in deeper water. A suspension cable guyed tower uses suspension cables to replace steel cross-arms, which allows the most reasonable stressing and the maximum cost-effectiveness of towers. The angle towers in the ±800-kV UHV DC demonstration project are shown in Figure 8.5. The use of flex elements such as flex legs or axial tubes, resonance is reduced and wave forces are deamplified. The concepts differ mainly in the means by which the loadings are transmitted to the seabed and in the form of the anchorage to the sea floor. Given satisfactory figures from these assessments, the forms of OTEC plant to be used, including combinations with other relevant DOWAs, are varied and include the following: Floating but constrained to maintain station. 2. Guyed towers can be assembled on the ground and the small wind turbine attached before lifting with a crane. It is 52.5 m high, 87 m wide, and weighs 20.9 tons. Schematic diagram of 1000-kV cup tower. A guyed tower may be applicable in deep hostile waters where the loads on the gravity base or jacket-type structures from the environment are prohibitively high. These towers can operate in water depths ranging from 457 to 914 m (1,500 to 3,000 ft ). Image: 1 & 2) conventional fixed platforms; 3) compliant tower; 4, 5) vertically moored tension leg and mini-tension leg platform; 6) spar; … 7.21). Nearly all other types are evolved from these two types. 7.17 shows a 1150-kV Y-shaped guyed tower designed in the former Soviet Union (Fig. At present the deepest is the Chevron Petronius tower in waters 623m deep. All of these systems are proven technology, and in use in offshore production worldwide. In the 1000-kV Jindongnan–Nanyang–Jingmen UHV AC pilot and demonstration project, both types are used. Floating production facilities . tension leg platforms), but compliant towers still demonstrate static stability albeit with greater degrees of lateral deformation (up to 2.5%) compared to land-based structures (usually 0.5% or less). A compliant tower (CT) is a fixed rig structure normally used for the offshore production of oil or gas. However the phase and form of the guy ten- 15 - Wood Group Mustang Deepwater Systems Global Distribution . A V-shaped guyed tower in three-phase inverted triangular configuration. Fixed Platforms: Compliant Towers 8 A compliant tower is similar to a traditional jacket platform and extends from surface to the sea bottom, and it is fairly transparent to waves. Several issues have to be pointed out: The structural behavior of fixed jacket platforms is different compared with others. Compliant Tower A compliant tower is a flexible structure with flex elements (principally flexible legs or axial tubes) to control mass and stiffness characteristics so as to mitigate the effects of periodic wind, wave and current forces. A TLP is a compliant, free-floating offshore platform concept. Figure 7.23. A double-circuit tower requires one less right-of-way than two single-circuit towers, which contributes to a significant reduction in the width of the right-of-way. Tension . Despite its flexibility, the CT system is sufficiently sturdy to withstand hurricane conditions. Compared with floating systems, such as Tension-leg platforms and SPARs, the production risers are conventional and are subjected to less structural demands and flexing. Vertical motion of structure restricted Can be used in very deep waters upto 2000m depth 28. [2]. F.B. Compliant Tower . At present the deepest is the Chevron Petronius tower in waters 623m deep. Kevlar, a synthetic fiber stronger and much lighter than steel, is being studied as a possible means of increasing the mooring depth limits of cables on guyed–towers and TLPs. We use cookies to help provide and enhance our service and tailor content and ads. However, because of cost, it becomes uneconomical to build compliant towers in depths greater than 1,000 meters. The first tower emerged in the early 1980s with the installation of Exxon's Lena oil platform. Compliant Tower Deck Fw (t) Tower Frame Ungrouted pile sliding inside the tower leg or pile guides Pile top weld connected to the tower at top. The tension ropes are supplanted by one particular floating casing which requires enough flexibility and The SALM system uses a yoke structure, buoyancy tank, and tensioned riser. Several types of compliant structures have been proposed and placed in service, including catenary-moored floating vessels, articulated columns, a guyed tower, and a tension leg platform. Compliant Tower Deck Fw (t) Tower Frame Ungrouted pile sliding inside the tower leg or pile guides Pile top weld connected to the tower at top. Figure 7.24. 18.17) in terms of supporting means. In areas with narrow line corridors, cat-head towers or even cat-head towers with three V-strings are often used; however, in other areas, cup towers are preferred. 15 - Wood Group Mustang Deepwater Systems Global Distribution . Zhenya Liu, in Ultra-High Voltage Ac/dc Grids, 2015. However, it has advantages of narrower right-of-way and uniform power-frequency field strength along the right-of-way. In addition, the former Soviet Union also developed a 1150-kV V-shaped guyed tower where three phases are arranged in triangular configuration (as shown in Fig. Unlike the fixed platform, the compliant tower withstands large lateral forces by sustaining significant lateral deflections, and is usually used in water depths between 1,000 and 2,000 feet. Compliant towers are designed to sustain significant lateral deflections and forces, and are typically used in water depths ranging from 1,500 to 3,000 feet (450 to 900 m). nique and to demonstrate its use on three types of compliant ocean structures: 1) the articulated tower, 2) the guyed tower, and 3) the tension leg platform. The tension ropes are supplanted by one particular floating casing which requires enough flexibility and Floating Structures † Floating Production System † Floating Production, Storage and … It can be seen that the options for OTEC plants are considerable and that optimization for a particular site involves the review of many variables. Naeim Nouri Samie MSc Hydraulic Structures, in Practical Engineering Management of Offshore Oil and Gas Platforms, 2016. Several types of compliant structures have been proposed and placed in service, including catenary-moored floating vessels, articulated columns, a guyed tower, and a tension leg platform. A Tension-leg platform is a vertically moored °oating structure normally used for the ofishore production of oil or gas, and is particularly suited for water depths around 1000m to 1200 metres (about 4000 ft). 1.5 Response Control Strategies 24. Tension leg platform is similar to sea star platform. This platform … A shuttle tanker is brought alongside to receive the processed crude oil and transport it to shore by means of a shuttle tanker or an export oil pipeline. 1.5.1 Active Control Algorithm 25. FIXED- Fixed Leg Platform (see below for full description) FPSO- Floating production, storage, and offloading. For these platforms normally all functions are performed on the same unit. Results from the guyed tower example indicate that a decoupled analysis yields conservative peak guy tension and deck displacement values. The structure is held in a fixed position by tensioned tendons, which provide for use of the TLP in a broad water depth range up to about 2000 m. And then, there is the question of whether the OTEC plant is for one or more of the following: In the longer term, there can be “grazing” OTEC plants—plants that move freely with currents or under their own power—for use as a source of power to the following: Produce liquid hydrogen, liquid ammonia, and the like for trans-shipment to other areas to be used in industrial processes and power generation, Process at sea ores and other raw materials that are energy intensive in the extraction of the refined product. For this paper, deepwater means leases located in water depths greater than 1,000 ft. It is 44 m high, 61 m wide, and weighs 11.5 tons. Tension- leg platform – Tension- leg platform are floating platforms, ususally the giant version of the Sea Star platforms, except the tension legs extend from the ocean floor to the platform itself. Compliant Tower . This tower type is recommended for 1000-kV double-circuit transmission lines. These differences allow the use of CTs in water depths ranging up to 3,000 ft, which is generally considered to be beyond the economic limit for fixed jacket-type platforms. Spar Subsea Infrastructure . William Crain, in Energy and Sea Power, 1981. 1.1 Introduction 1. Figure 7.28. The former Soviet Union, Japan, the United States, Italy, Canada, Brazil, and other countries have constructed pilot sections of UHV transmission lines of various scales, and launched extensive theoretical and experimental studies on UHV transmission lines including tower types. Guy wires are added as the height is increased to support the tower. It is 60 m high. While the structures were different, we observed similar distributions of Lophelia at both locations. Because the cold water is at depths of up to 1000 m, and because the flow of water required per megawatt of power output is in the range of 4 to 8 m3/s, the scale of the plant will be apparent. The self-supporting tower is one of the most widely used tower types in the existing line projects around the world. 7.19 shows a 1110-kV suspension cable guyed tower designed by the Department of Energy of the United States. In such a case a floating production system is more appropriate, even with the increased cost of … Below is a description of some basic UHV tower types with reference to researches and applications of UHV transmission line towers used worldwide. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B9780080443812500047, URL: https://www.sciencedirect.com/science/article/pii/B9780123859990000047, URL: https://www.sciencedirect.com/science/article/pii/B9780128093313000016, URL: https://www.sciencedirect.com/science/article/pii/B9780128051931000185, URL: https://www.sciencedirect.com/science/article/pii/B9780080280356500099, URL: https://www.sciencedirect.com/science/article/pii/B9780080280356500154, URL: https://www.sciencedirect.com/science/article/pii/B9780128051931000070, URL: https://www.sciencedirect.com/science/article/pii/B9780128021613000081, URL: https://www.sciencedirect.com/science/article/pii/B012176480X003430, URL: https://www.sciencedirect.com/science/article/pii/B9781856175586000039, Historical Development of Offshore Structures, Subrata Chakrabarti, ... Cuneyt Capanoglu, in, Naeim Nouri Samie MSc Hydraulic Structures, in, Practical Engineering Management of Offshore Oil and Gas Platforms, Disciplines Involved in Offshore Platforms Design, Tower types commonly used in UHVDC transmission lines can be classified into, OCEAN ENGINEERING NEEDS FOR U.S. ENERGY SUPPLY, Equipment of UHV Overhead Transmission Lines, Subsea and Deepwater Oil and Gas Science and Technology. They are flexible in design to sway and move laterally with the forces of wind and waves. Process design, power generation/distribution, control systems, piping, and installed equipment more or less follow the same concepts as explained in this book. A self-supporting cup tower. Compliant-tower rigs are similar to fixed platforms, since both are anchored to the seabed and hold most of their equipment above the surface. Most all operating platforms have one of these systems, in one form or another, and through them, they manage the key barriers to failure and the performance standards of the vessel. Tension-leg platforms . Single-circuit self-supporting towers commonly used in UHV AC transmission lines are typically cup towers with three-phase conductors in horizontal configuration and cat-head towers with three-phase conductors in triangular configuration. Compared with floating systems, such as tension-leg platforms and SPARs, the production risers are conventional and are subjected to less structural demands and flexing. FUNCTIONAL SCHEMATIC OF A TYPICAL TLP 30. To obtain the 2.5% efficiency, the standard design case temperature difference of some 20°C is required, but clearly the larger the temperature difference, the greater the efficiency of the plant. The Ursa tension leg platform is an oil platform with a tension leg structure located at about 130 miles (210 km) southeast of New Orleans in the Gulf of MexicoIt is operated by Shell Oil Company.It has a total height from the seabed to its top of 4,285 feet (1,306 m). Tension Leg Platform (TLP) consists of a floating structure held in place by vertical, tensioned tendons connected to the sea floor by pile-secured templates. Leg Platform . The rig consists of narrow, flexible (compliant) towers and a piled foundation supporting a conventional deck for drilling and production operations. The rig consists of narrow, flexible (compliant) towers and a piled foundation supporting a conventional deck for drilling and production operations. Fig. Figure 7.20. The surface facilities are smaller by design on CTs than on FPs because of the decreased jacket dimensions that support them. The first tower emerged in the early 1980s SPAR- SPAR Platform - floating production system. However, because of cost, it becomes uneconomical to build CTs in depths greater than 3000 ft. The tension–leg concept calls for a floating platform permanently anchored to the seafloor by steel cables under tension. Its total weight is 25%–40% less than that of a V-shaped guyed tower; however, it has the largest footprint. A 1000-kV double-circuit steel tubular angle tower in Japan. The Chevron Petronius platform (a deep water CT) is a crude oil and natural gas platform in the Gulf of Mexico, which stands 2,000 ft above the ocean floor and the structure is partially supported by buoyancy. Natural periods are usually greater than 1,000 meters fixed platforms, 2016 off the.. In Fig 7.24 shows a 1100-kV self-supporting cat-head tower and angle tower in waters 623m deep is enough. 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