Gravity base structures (CBS) 2. These structures are basically concrete shells assembled in circular array with stem columns projecting to above water to support the deck and facilities. However, the development of fields in the future using this technology may be limited, primarily in light of the trend toward subsea wells with long tie-backs and floating production systems . Offshore platforms are not built in situ, as most land‐based structures are, but are built somewhere else and towed to and installed at the site. Depending on the circumstances, platforms may be attached to the ocean floor, consist of an artificial island, or be floating. Wellhead Platform (WHP) CONCRETE GRAVITY STRUCTURE (CGS) - CONSTRUCTION Reference # 8.34.1.080 Husky Energy Inc. (Husky), operator of the White Rose Field and satellite extensions, is seeking prequalification responses from interested companies / consortia / joint ventures for the Further projects have been the Malampaya project in the Philippines and the Wandoo Full Field Development on the North West Shelf of Western Australia. Located off the Louisiana coast in Breton Sound Block 53, the structure rests in an approximate water depth of 12 feet on a totally submerged hull section used for oil storage. Floating production, storage, and offloading systems (FPSOS) receive crude oil from deep-water wells and store it in their hull tanks until the crude is transferred into tank ships or transport barges. Please check your email for instructions on resetting your password. [not verified in body]. Most of the designs have in common a base caisson (normally for storage of oil) and shafts penetrating the water surface to carry the topside. Those large structures house machinery and equipment needed to drill and/or extract oil and gas. [citation needed]. When fiords have not been available, concrete gravity platforms have also been constructed in a dry dock, and the topside is lift‐installed. Concrete cylinder pile-supported structures 3. Condeep is a make of gravity-based structure for oil platforms developed by engineer Olav Mo in Hoeyer-Ellefsen and fabricated by Norwegian Contractors in Stavanger, Norway. Temporary floating structures such as the Condeep platforms float during construction but are towed out and finally ballasted until they sit on the sea floor. A more recent development is concrete sub-sea structures. Decommissioning of Offshore Concrete Gravity Based Structures (CGBS) in the OSPAR Maritime Area /Based Structures. Further example for the C G DORIS designs are the Frigg platforms, the Ninian Central Platform and the Schwedeneck platforms. Most gravity-type platforms need no additional fixing because of their large foundation dimensions and extremely high weight. Several conceptual studies have shown recently, that concrete support structures for offshore wind turbines are very competitive compared to common steel structures, especially for larger water depths. The design typically consists of a large volume caisson based on the sea floor merging into a monolithic structure, which is offering the base for the deck. BALLASTI NG AND ANTI-EROSION. Floating structures 1. But concrete structures are not only limited to applications within the oil and gas industry. They must have sufficient weight to remain in place when subjected to waves, current, and wind. At the time of this writing (2016), there were 50 major offshore concrete platforms for the oil and gas industry in the world, almost all of them of the gravity type. Floating piers and docks 3. [Video footage] Low angle footage of an oil platform, planted atop very tall concrete legs in the ocean, seen against the background of blue sky. The West White Rose Project will be developed through a fixed drilling platform consisting of a concrete gravity structure (CGS), built by the SNC-Lavalin- Dragados-Pennecon General Partnership (SDP), and an integrated topsides facilities. Keywords: Offshore concrete structures, gravity based structure, design, harsh environment, oil and gas, arctic. Offshore gravity based concrete installations pose particular problems for decommissioning, not least because of the sheer physical size and engineering complexity of the structure themselves. Following table summarizes the major existing offshore concrete structures. Use the link below to share a full-text version of this article with your friends and colleagues. Concrete gravity platforms are structures resting on the seabed. Since that time, more than 1000 functionally similar concrete structures have been built in that area (Norwegian Con-tractors, 1991a). This barge is built of reinforced and prestressed concrete containing cylindrical tanks each having a cross-section perpendicular to its longitudinal axes that comprises a preferably circular curved portion corresponding to the bottom. For activities which require a stable offshore platform, the vessel is then ballasted down so that the pontoons are submerged, and only the buoyant columns pierce the water surface - thus giving the vessel a substantial buoyancy with a small water-plane area. Tension Leg Platform 3. Heavy topsides 3. The original proposal of the French group C G DORIS (Compagnie General pour les Developments Operationelles des Richesses Sous-Marines) for a prestressed post-tensioned concrete "island" structure was adopted on cost and operational grounds. Directory and listing of concrete gravity base structures from around the world including images, technical data, literature and other project information. PROTECTION. The Sleipner A platform produces oil and gas in the North Sea and is supported on the seabed at a water depth of 82 m. It is a Condeep type platform with a concrete gravity base structure consisting of 24 cells and with a total base area of 16 000 m 2. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username, I have read and accept the Wiley Online Library Terms and Conditions of Use, https://doi.org/10.1002/9781118476406.emoe370. DORIS was general contractor responsible for the structural design: the concrete design was prepared and supervised on behalf of DORIS by Europe-Etudes. Floating bridges 5. The first concrete gravity-base structure in U.S. waters was installed in 1978 (Hunteman et al., 1979). Their configuration in contact with the sea bottom must be adapted to the specific soil conditions at the site. Their configuration in contact with the sea bottom must be adapted to the specific soil conditions at the site. McAlpine constructed three concrete platforms for the North Sea oil industry at Ardyne Point. Concrete Gravity Base Structures (CGBS) is a further development of the first-generation Condeep drilling/production platforms installed in the North Sea between the late 1970s and mid '90s. Statoil's Heidrun TLP is the only one with a concrete hull, all other TLPs have steel hulls. [citation needed]. Smaller structures may be built on barges. Fixed structures are mostly built as concrete gravity based structures (CGS, also termed as caisson type), where the loads bear down directly on the uppermost layers as soil pressure. In addition to FPSO’s, there have been a number of ship-shaped Floating Storage and Offloading (FSO) systems (vessels with no production processing equipment) used in these same areas to support oil and gas developments. 2004. massive structure dam which is constructed of concrete or stone masonry The first concrete oil platform has been installed in the North Sea in the Ekofisk field in 1973 by Phillips Petroleum. Historically, one concrete gravity platform is installed, on average, every year. lego moc time – “offshore concrete gravity platform” 17/03/2017 Rusty Comments 5 comments Continuing with my community MOC blog series I spotted this creations the other day over on one of the LEGO Facebook groups and instantly fell in love with it. Condeep refers to a make of gravity base structure for oil platforms developed and fabricated by Norwegian Contractors in Norway. Deep-draft concrete floaters (DDCFs) 3. ABSTRACT In June, 1978, the first concrete gravity platform was installed in United States Federal offshore waters. or most recent projects are:[citation needed]. XIII. 1 The first concrete platform for oil and gas production in the Gulf of Mexico was installed in 1950 and since then there have been more than 1000 small concrete-like structures built in that area ().But the first major concrete offshore structure supported at its base by gravity, gravity base structure (GBS), was installed in 1973 in the North Sea: the Ekofisk tank. During the installation these tanks have been used as ballast compartment. The only concrete semi-submersible in existence[when?] This content is only available via PDF. Concrete gravity platforms are structures resting on the seabed. The design and construction of the huge concrete gravity base structures represent a remarkable achievement by the offshore industry. The most common concrete designs are:[citation needed]. A view from the South East of Troll A Platform, A 'Statfjord' Gravity base structure under construction, Floating production, storage, and offloading, The sinking of the Sleipner A offshore platform, https://en.wikipedia.org/w/index.php?title=Offshore_concrete_structure&oldid=972103228, Articles with unsourced statements from October 2014, Wikipedia articles needing clarification from October 2014, All articles with vague or ambiguous time, Vague or ambiguous time from October 2014, Creative Commons Attribution-ShareAlike License, Snorre Concrete Foundation Templates (CFT), Condeep (with one, two, three or four columns), This page was last edited on 10 August 2020, at 05:12. Located off the Louisiana coast in Breton Sound Block 53, the structure rests in an approximate water depth of 12 feet on a totally submerged hull section used for oil storage. The single main leg is surrounded by an outer breaker wall perforated with so called Jarlan holes. The Sleipner platform was the first of three concrete gravity base structures to be used to extract oil and gas from this field, and great effort was placed on a timely start-up of gas deliveries in order to ensure the credibility of Norway as a reliable European energy partner. Fig. The Condeep Platforms Brent B (1975) and Brent D (1976) were designed for a water depth of 142m in the Brent oilfield operated by Shell. Because of the low stiffness in those systems, the natural frequency is low and the structure can move in all six degrees of freedom. Industrial plant ships 4. If you have previously obtained access with your personal account, please log in. Corpus ID: 116517068. INTRODUCTION Experience with concrete ships since the 1920’s and floating bridges in Washington State since 1955 demonstrates that concrete is … In the foreground, three vessels are anchored in the ocean around the platform. Concrete tension-leg platforms (TLPs) 2. Their main mass is represented by the storage tank (ca. To achieve its goal and extract oil within five years after discovering the Brent reservoir Shell • This is innovative technology for the region: a proven concept around the world, Husky is the first to bring it to Newfoundland and Labrador • The platform is a fixed drilling rig, which will produce back to the SeaRose FPSO. and you may need to create a new Wiley Online Library account. In June, 1978, the first concrete gravity platform was installed in United States Federal offshore waters. Sea. Soil conditions that make piled substructures unattractive, such as on Australia's North-West Shelf 4. Furthermore, the caisson could be used as storage volume for oil or other liquids. Redpath Dorman Long at Methil in Fife, Scotland getting Brent A, the two concrete Condeeps B and D were to be built in Norway by Norwegian Contractors (NC) of Stavanger, and C (also concrete) was to be built by McAlpine at Ardyne Point on the Clyde (which is known as the ANDOC (Anglo Dutch Offshore Concrete) design). Remote hub applications at the edge of the continental shelf where shallow water processing can be provided for deepwater subsea wells 5. Encyclopedia of Maritime and Offshore Engineering. The platform is held in place with large steel tendons fastened to the sea floor. GBS have been installed in water-depths of up to 300 m. Most gravity based structures are made from concrete although one steel gravity base platform, Maureen, was installed in the North Sea. An FSO is typically used as a storage unit in remote locations far from pipelines or other infrastructures. They serve the same purpose as their steel counterparts in the oil and gas production and storage. At present, the heaviest reinforced concrete structure is the Gullfaks-C Platform with a total heiõht of 380 m, a deadweight of 750000 t, and a crude oil storage capacity of 2 million barrels (320000 m D) (Fig. The platform is floated to the drilling site in a vertical position, and at the site tall caissons that serve as the foundation of the platform are flooded so that the platform submerges and comes to rest on bottom. Among the largest Condeep type platform are the Troll A platform and the Gullfaks C. Troll A was built within four years and deployed in 1995 to produce gas from the Troll oil field which was developed by Norske Shell, since 1996 operated by Statoil. The original Condeep always rests on the sea floor, and the shafts rise to about 30m above the sea level. A gravity-based structure (GBS) is a massive foundation placed on the seabed to serve as the base for offshore structures. At tow-ocu this concrete gravity base structure (CBS) had a weight of 1.5 million tons. This technique helps to maximise economy and provide a robust offshore emplacement methodology. Gravity base structures are among the biggest and most impressive feats of engineering in the oil and gas industry. for LNG. The ANDOC design can be considered as the British construction industry's attempt to compete with Norway in this sector. The structure has a shape not unlike a marine sea island and is surrounded by a perforated breakwater wall (Jarlan patent). Three of the cells are extended into shafts tapering off at the surface and carrying a steel deck. Learn about our remote access options, Dr.techn.Olav Olsen (OO), Lysaker, Norway. The ANDOC type is very similar to the Sea Tank design, but the four concrete legs terminate and steel legs take over to support the deck. Since then 47 major concrete offshore structures have been built, whereby 21 of the 47 concrete substructures have been designed (concept and detail designs ) by Dr. techn. Concrete gravity platforms are structures resting on the seabed. Permanent floating concrete structures have various uses including the discovery of oil and gas deposits, in oil and gas production, as storage and offloading units and in heavy lifting systems. There are various types of offshore oil and gas platforms 1. Gravity-type concrete platforms are used for oil-drilling purpose in the oil industry. Finite Element Analysis of Concrete Gravity Based Platform Subjected to Sudden Crash (Impact) Load Using ANSYS @article{Alerechi2018FiniteEA, title={Finite Element Analysis of Concrete Gravity Based Platform Subjected to Sudden Crash (Impact) Load Using ANSYS}, author={L. W. Alerechi and O. O. Odunfa}, journal={Journal of Engineering and Technology}, year={2018}, volume={2} } Browse other articles of this reference work: The full text of this article hosted at iucr.org is unavailable due to technical difficulties. Floating units may be held in position by anchored wires or chains in a spread mooring pattern. This wall is intended to break up waves, thus reducing their forces. concrete platform for oil and gas production in the Gulf of Mexico was installed in 1950. In the shafts normally utility systems for offloading, drilling, draw down and ballast are put up. The platform deck itself is not a part of the construction. Since concrete is quite resistant to corrosion from salt water and keeps maintenance costs low, floating concrete structures have become increasingly attractive to the oil and gas industry in the last two decades. The first concrete gravity platform in the North Sea was a C G Doris platform, the Ekofisk Tank, in Norwegian waters. Offshore concrete structures have been in use successfully for about 30 years. This unique way of construction favors deep fiords that give sheltered construction sites and sufficient depth for construction. The construction commences in a dry dock adjacent to the sea. Common designs for floating concrete structures are the barge or ship design, the platform design (semi-submersible, TLP) as well as the floating terminals e.g. Some of the semi-submersible vessels only have a single caisson, or column, usually denoted as a buoy while others utilize three or more columns extended upwardly from buoyant pontoons. Working off-campus? In the shafts normally utility systems for offloading, drilling, draw down and ballast are put up. Simplicity and repetition of concrete structural elements, low reinforcement and pre-stress densities as well as the use of normal density concrete lead to economical construction costs. Other offshore structures The caisson provides buoyancy during construction and towing and acts also as a foundation structure in the operation phase. Learn more. 2.19). Concrete Gravity-Based Structure Construction of the Hebron offshore oil platform by Widianto, Jameel Khalifa, Gus Taborda, and Knut Bidne T he Hebron offshore oil development project consists of the following major components (Fig. A Tension Leg Platform is a buoyant platform, which is held in place by a mooring system. The tanks serve as storage of crude oil in the operation phase. If you do not receive an email within 10 minutes, your email address may not be registered, Most of the designs have in common a base caisson (normally for storage of oil) and shafts penetrating the water surface to carry the topside. They must have sufficient weight to remain in place when subjected to waves, current, and wind. [citation needed] They must have sufficient weight to remain in place when subjected to waves, current, and wind. Steel Jacket Fixed Platform 2. 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