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. TLP mooring is different to conventional chained or wire mooring systems. The first concrete gravity platform in the North Sea was a C G Doris platform, the Ekofisk Tank, in Norwegian waters. [not verified in body]. The most common concrete designs are:[citation needed]. Building the topside structure and the concrete substructure simultaneously, and then mating the two in sheltered waters before towing the complete platform to site, saves valuable time. 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 [citation needed]. Browse other articles of this reference work: The full text of this article hosted at iucr.org is unavailable due to technical difficulties. Olav Olsen. The key characteristics singly, or in combination, that make CGS units the preferred solution are: 1. [citation needed]. Three of the cells are extended into shafts tapering off at the surface and carrying a steel deck. Depending on the circumstances, platforms may be attached to the ocean floor, consist of an artificial island, or be floating. The only concrete semi-submersible in existence[when?] 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. 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. ABSTRACT In June, 1978, the first concrete gravity platform was installed in United States Federal offshore waters. This content is only available via PDF. Concrete cylinder pile-supported structures 3. developing West White Rose with a concrete gravity (CGS) supported wellhead platform. Learn about our remote access options, Dr.techn.Olav Olsen (OO), Lysaker, Norway. 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. [citation needed], Since the 1970s, several fixed concrete platform designs have been developed. Their main mass is represented by the storage tank (ca. Concrete platforms are built and installed in a different way from steel jackets. Typical for the Arup CGS is the inclined installation technique. 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. Corpus ID: 116517068. The CGBS have no oil storage facilities and the topside installations will be carried out in the field by a float-over mating method. Concrete platforms are generally larger structure than steel jackets and are not piled but instead sit … Condeep usually consists of a base of concrete oil storage tanks from which one, three or four concrete shafts rise. Directory and listing of concrete gravity base structures from around the world including images, technical data, literature and other project information. 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 last two chapters give detailed insights into the analysis and design of framed and concrete gravity platform offshore structures using API code procedures. Tension Leg Platform 3. Floating piers and docks 3. A detailed overview about Condeep platforms is given in a separate article. Following table summarizes the major existing offshore concrete structures. 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. Concrete tension-leg platforms (TLPs) 2. [clarification needed] They are highly durable, constructed of almost maintenance-free material, suitable for harsh and/or arctic environment (like ice and seismic regions), can carry heavy topsides, often offer storage capacities, are suitable for soft grounds and are very economical for water depths larger than 150m. Soil conditions that make piled substructures unattractive, such as on Australia's North-West Shelf 4. 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. Since that time, more than 1000 functionally similar concrete structures have been built in that area (Norwegian Con-tractors, 1991a). Keywords: Offshore concrete structures, gravity based structure, design, harsh environment, oil and gas, arctic. A gravity-based structure (GBS) is a massive foundation placed on the seabed to serve as the base for offshore structures. The design, material specifications, and construction of GBS systems are covered by “Guide for the Design and Construction of Fixed Offshore Concrete Structures (ACI 357R).” This wall is intended to break up waves, thus reducing their forces. Further example for the C G DORIS designs are the Frigg platforms, the Ninian Central Platform and the Schwedeneck platforms. Working off-campus? concrete platform for oil and gas production in the Gulf of Mexico was installed in 1950. 1. is Troll B. 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. View the article PDF and any associated supplements and figures for a period of 48 hours. On October 18th, 2019, the Husky Energy West White Rose Concrete Gravity Structure (CGS) construction project team successfully completed the 4th quadrant base cassion slipform of the fixed drilling platform. This design is quite similar to the Condeep type. Sea. [citation needed] The platform is held in place with large steel tendons fastened to the sea floor. Historically, one concrete gravity platform is installed, on average, every year. Remote hub applications at the edge of the continental shelf where shallow water processing can be provided for deepwater subsea wells 5. • 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. 2.19). In the foreground, three vessels are anchored in the ocean around the platform. 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. 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. Different types of offshore concrete structures are: 1. 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. FPSO or FSO systems are typically barge/ship-shaped and store crude oil in tanks located in the hull of the vessel. Learn more. Concrete gravity platforms are structures resting on the seabed. Encyclopedia of Maritime and Offshore Engineering. Semi-submersible platforms have the principal characteristic of remaining in a substantially stable position, presenting small movements when they experience environmental forces such as the wind, waves and currents. Use the link below to share a full-text version of this article with your friends and colleagues. The concrete gravity platform by its name derive its horizontal stability against environmen-tal forces by means of its weight. 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. Concrete gravity platforms are structures resting on the seabed. BALLASTI NG AND ANTI-EROSION. Concrete gravity platform rig: A rigid offshore drilling platform built of steel-reinforced concrete and used to drill development wells. 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. Please check your email for instructions on resetting your password. Society of Petroleum Engineers 1): • Reinforced concrete gravity-based structure (GBS); • Topsides structure with all systems and equipment Since the 1970s, several fixed concrete platform designs have been developed. Current[when?] Furthermore, the caisson could be used as storage volume for oil or other liquids. The first concrete oil platform has been installed in the North Sea in the Ekofisk field in 1973 by Phillips Petroleum. massive structure dam which is constructed of concrete or stone masonry for LNG. 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. 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. The platform deck itself is not a part of the construction. 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. This technique helps to maximise economy and provide a robust offshore emplacement methodology. They must have sufficient weight to remain in place when subjected to waves, current, and wind. The design and construction of the huge concrete gravity base structures represent a remarkable achievement by the offshore industry. Floatable/bottom-founded concrete-hull structures 2. Their configuration in contact with the sea bottom must be adapted to the specific soil conditions at the site. The Arup CGS are designed to be simple to install, and are fully removable. The original Condeep always rests on the sea floor, and the shafts rise to about 30m above the sea level. Industrial plant ships 4. Deep-draft concrete floaters (DDCFs) 3. 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 . XIII. 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. INTRODUCTION Experience with concrete ships since the 1920’s and floating bridges in Washington State since 1955 demonstrates that concrete is … 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 gravity bases are usually in geometric sections separated by short steel and concrete skirts and can be up to 150m wide. [citation needed], Concrete offshore structures show an excellent performance. Condeep refers to a make of gravity base structure for oil platforms developed and fabricated by Norwegian Contractors in Norway. This unique way of construction favors deep fiords that give sheltered construction sites and sufficient depth for construction. The sea bed soils at platform sites are all nearly level at the surface and consist of Pleistocene dense sands and pre-consolidated clays, though weaker layers are known to exist from, possibly, permafrost effects. Unlimited viewing of the article/chapter PDF and any associated supplements and figures. Those large structures house machinery and equipment needed to drill and/or extract oil and gas. Subjects: Offshore Facilities and Subsea Systems. Illustration of Construction and Installation Procedu res for Concrete Gravity Platform s (Sadeghi, 2001). These structures are basically concrete shells assembled in circular array with stem columns projecting to above water to support the deck and facilities. Offshore concrete structures have been in use successfully for about 30 years. The ANDOC design can be considered as the British construction industry's attempt to compete with Norway in this sector. They must have sufficient weight to remain in place when subjected to waves, current, and wind. When fiords have not been available, concrete gravity platforms have also been constructed in a dry dock, and the topside is lift‐installed. Decommissioning of Offshore Concrete Gravity Based Structures (CGBS) in the OSPAR Maritime Area /Based Structures. The Arup dry-build Concrete Gravity Substructure (CGS) concept was originally developed by Arup in 1989 for Hamilton Brothers' Ravenspurn North. The first concrete gravity-base structure in U.S. waters was installed in 1978 (Hunteman et al., 1979). 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. Steel Jacket Fixed Platform 2. To achieve its goal and extract oil within five years after discovering the Brent reservoir Shell 100m diameter and 56m high, consisting of 19 cylindrical compartments with 20m diameter). Semi-Submersible platforms have pontoons and columns, typically two parallel spaced apart pontoons with buoyant columns upstanding from those pontoons to support a deck. Other offshore structures 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. But concrete structures are not only limited to applications within the oil and gas industry. The caisson provides buoyancy during construction and towing and acts also as a foundation structure in the operation phase. [1] 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. 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. [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. 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. Fig. They must have sufficient weight to remain in place when subjected to waves, current, and wind. 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 tendons are held in tension by the buoyancy of the hull. Their turret structures are designed to anchor the vessel, allow “weathervaning” of the units to accommodate environmental conditions, permit the constant flow of oil and production fluids from vessel to undersea field, all while being a structure capable of quick disconnect in the event of emergency. 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. Requirement for oil or condensate storage 2. Condeep is an abbreviation for concrete deep water structure.A Condeep usually consists of a base of concrete oil storage tanks from which one, three or four concrete shafts rise. 2004. Semi-submersible marine structures are typically only movable by towing. Because of the low stiffness in those systems, the natural frequency is low and the structure can move in all six degrees of freedom. Heavy topsides 3. Floating units may be held in position by anchored wires or chains in a spread mooring pattern. A more recent development is concrete sub-sea structures. or most recent projects are:[citation needed]. 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. 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} } 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. 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. Further projects have been the Malampaya project in the Philippines and the Wandoo Full Field Development on the North West Shelf of Western Australia. The structure has a shape not unlike a marine sea island and is surrounded by a perforated breakwater wall (Jarlan patent). FPSO – Floating Production, Storage Offloader From the above we shall examine the steel jacket fixed platform in the following sections. In June, 1978, the first concrete gravity platform was installed in United States Federal offshore waters. 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). 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. If you have previously obtained access with your personal account, please log in. They serve the same purpose as their steel counterparts in the oil and gas production and storage. Gravity-type concrete platforms are used for oil-drilling purpose in the oil industry. Concrete gravity platforms are structures resting on the seabed. Floating structures 1. Concrete gravity base Platform 4. Floating bridges 5. platform, concrete gravity platform erik hjelde, north sea, concrete platform, disposal option, spe 86813, operation, concrete gravity platform, disposal, concrete substructure. 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. A concrete gravity platform is one that is placed on the seabed, and by its own weight, is capable of withstanding the environmental forces (wind and waves) it may be exposed to during its lifetime. At tow-ocu this concrete gravity base structure (CBS) had a weight of 1.5 million tons. 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. The construction commences in a dry dock adjacent to the sea. The first barge of prestressed concrete has been designed in the early 1970s as an LPG (liquefied petroleum gas) storage barge in the Ardjuna Field (Indonesia). Desire to have a higher local c… 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. 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. Floating units serve as productions units, storage and offloading units (FSO) or for crude oil or as terminals for liquefied natural gas (LNG). Concrete offshore structures are mostly used in the petroleum industry as drilling, extraction or storage units for crude oil or natural gas. Unlimited viewing of the article PDF and any associated supplements and figures. 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. [citation needed]. Their configuration in contact with the sea bottom must be adapted to the specific soil conditions at the site. A Tension Leg Platform is a buoyant platform, which is held in place by a mooring system. This allows the inshore installation of deck girders and equipment and the later transport of the whole structure to the installation site. 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. , and wind four cells are extended into shafts tapering off at the site a part of gravity-base. 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