This allows the inshore installation of deck girders and equipment and the later transport of the whole structure to the installation site. 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. PROTECTION. ABSTRACT In June, 1978, the first concrete gravity platform was installed in United States Federal offshore waters. 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. Gravity-type concrete platforms are used for oil-drilling purpose in the oil industry. 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 Generally, offshore concrete structures are classified into fixed and floating structures. Since that time, more than 1000 functionally similar concrete structures have been built in that area (Norwegian Con-tractors, 1991a). 1): • Reinforced concrete gravity-based structure (GBS); • Topsides structure with all systems and equipment 2004. Concrete tension-leg platforms (TLPs) 2. 1. BALLASTI NG AND ANTI-EROSION. 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. Concrete gravity platform rig: A rigid offshore drilling platform built of steel-reinforced concrete and used to drill development wells. 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. 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. Gravity base structures (CBS) 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. The first concrete gravity-base structure in U.S. waters was installed in 1978 (Hunteman et al., 1979). [citation needed], Concrete offshore structures show an excellent performance. Fig. Those large structures house machinery and equipment needed to drill and/or extract oil and gas. 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. A detailed overview about Condeep platforms is given in a separate article. [citation needed]. A more recent development is concrete sub-sea structures. The Arup CGS are designed to be simple to install, and are fully removable. Illustration of Construction and Installation Procedu res for Concrete Gravity Platform s (Sadeghi, 2001). Concrete offshore structures are mostly used in the petroleum industry as drilling, extraction or storage units for crude oil or natural gas. They must have sufficient weight to remain in place when subjected to waves, current, and wind. Floating piers and docks 3. Corpus ID: 116517068. The tanks serve as storage of crude oil in the operation phase. 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. [citation needed] TLP mooring is different to conventional chained or wire mooring systems. A gravity-based structure (GBS) is a massive foundation placed on the seabed to serve as the base for offshore structures. Sea. 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. Smaller structures may be built on barges. In the shafts normally utility systems for offloading, drilling, draw down and ballast are put up. If you do not receive an email within 10 minutes, your email address may not be registered, Olav Olsen. This content is only available via PDF. Use the link below to share a full-text version of this article with your friends and colleagues. 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. There are various types of offshore oil and gas platforms 1. Depending on the circumstances, platforms may be attached to the ocean floor, consist of an artificial island, or be floating. This wall is intended to break up waves, thus reducing their forces. The first concrete oil platform has been installed in the North Sea in the Ekofisk field in 1973 by Phillips Petroleum. Deep-draft concrete floaters (DDCFs) 3. Concrete gravity platforms are structures resting on the seabed. The only concrete semi-submersible in existence[when?] When fiords have not been available, concrete gravity platforms have also been constructed in a dry dock, and the topside is lift‐installed. Desire to have a higher local c… Most gravity-type platforms need no additional fixing because of their large foundation dimensions and extremely high weight. [citation needed], Since the 1970s, several fixed concrete platform designs have been developed. Four cells are elongated to shafts supporting the platform deck. Historically, one concrete gravity platform is installed, on average, every year. Since the 1970s, several fixed concrete platform designs have been developed. Subjects: Offshore Facilities and Subsea Systems. FPSO – Floating Production, Storage Offloader From the above we shall examine the steel jacket fixed platform in the following sections. Browse other articles of this reference work: The full text of this article hosted at iucr.org is unavailable due to technical difficulties. Tension Leg Platform 3. The first concrete gravity platform in the North Sea was a C G Doris platform, the Ekofisk Tank, in Norwegian waters. But concrete structures are not only limited to applications within the oil and gas industry. [citation needed]. The last two chapters give detailed insights into the analysis and design of framed and concrete gravity platform offshore structures using API code procedures. Concrete offshore platforms of the gravity-base type are almost always constructed in their vertical attitude. The gravity bases are usually in geometric sections separated by short steel and concrete skirts and can be up to 150m wide. 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 structure has a shape not unlike a marine sea island and is surrounded by a perforated breakwater wall (Jarlan patent). The platform is held in place with large steel tendons fastened to the sea floor. for LNG. Further example for the C G DORIS designs are the Frigg platforms, the Ninian Central Platform and the Schwedeneck platforms. Heavy topsides 3. 100m diameter and 56m high, consisting of 19 cylindrical compartments with 20m diameter). massive structure dam which is constructed of concrete or stone masonry A Tension Leg Platform is a buoyant platform, which is held in place by a mooring system. 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. Concrete platforms are built and installed in a different way from steel jackets. [citation needed]. Condeep usually consists of a base of concrete oil storage tanks from which one, three or four concrete shafts rise. 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. 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. The construction commences in a dry dock adjacent to the sea. Furthermore, the caisson could be used as storage volume for oil or other liquids. 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. DORIS was general contractor responsible for the structural design: the concrete design was prepared and supervised on behalf of DORIS by Europe-Etudes. 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 design and construction of the huge concrete gravity base structures represent a remarkable achievement by the offshore industry. Bottom-founded structures 1. Semi-submersible marine structures are typically only movable by towing. Requirement for oil or condensate storage 2. [1] Statoil's Heidrun TLP is the only one with a concrete hull, all other TLPs have steel hulls. divided up the construction of four offshore platforms. Encyclopedia of Maritime and Offshore Engineering. Concrete platforms are generally larger structure than steel jackets and are not piled but instead sit … This design is quite similar to the Condeep type. 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. 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. They serve the same purpose as their steel counterparts in the oil and gas production and storage. 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. Floating structures 1. Soil conditions that make piled substructures unattractive, such as on Australia's North-West Shelf 4. Their main mass is represented by the storage tank (ca. 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 . 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. FPSO or FSO systems are typically barge/ship-shaped and store crude oil in tanks located in the hull of the vessel. Directory and listing of concrete gravity base structures from around the world including images, technical data, literature and other project information. Their configuration in contact with the sea bottom must be adapted to the specific soil conditions at the site. Please check your email for instructions on resetting your password. platform, concrete gravity platform erik hjelde, north sea, concrete platform, disposal option, spe 86813, operation, concrete gravity platform, disposal, concrete substructure. 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. Remote hub applications at the edge of the continental shelf where shallow water processing can be provided for deepwater subsea wells 5. Society of Petroleum Engineers 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. 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} } XIII. Learn about our remote access options, Dr.techn.Olav Olsen (OO), Lysaker, Norway. is Troll B. 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. 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 caisson provides buoyancy during construction and towing and acts also as a foundation structure in the operation phase. Industrial plant ships 4. Following table summarizes the major existing offshore concrete structures. Those tendons are held in tension by the buoyancy of the hull. CONCRETE gravity base Description Offshore oil development, especially in the North Sea, has brought up a completely different design of fixed platform: concrete platforms. 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. 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. 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. Because of the low stiffness in those systems, the natural frequency is low and the structure can move in all six degrees of freedom. 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. Typical for the Arup CGS is the inclined installation technique. The key characteristics singly, or in combination, that make CGS units the preferred solution are: 1. 2.19). Unlimited viewing of the article/chapter PDF and any associated supplements and figures. To achieve its goal and extract oil within five years after discovering the Brent reservoir Shell 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. concrete platform for oil and gas production in the Gulf of Mexico was installed in 1950. 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). 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. Condeep refers to a make of gravity base structure for oil platforms developed and fabricated by Norwegian Contractors in Norway. The Arup dry-build Concrete Gravity Substructure (CGS) concept was originally developed by Arup in 1989 for Hamilton Brothers' Ravenspurn North. 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. 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. [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. If you have previously obtained access with your personal account, please log in. In June, 1978, the first concrete gravity platform was installed in United States Federal offshore waters. The original Condeep always rests on the sea floor, and the shafts rise to about 30m above the sea level. or most recent projects are:[citation needed]. 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 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). Their configuration in contact with the sea bottom must be adapted to the specific soil conditions at the site. Learn more. 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. An FSO is typically used as a storage unit in remote locations far from pipelines or other infrastructures. • 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. Overall, this book is a comprehensive presentation of the analysis and design of steel and concrete offshore structures. This unique way of construction favors deep fiords that give sheltered construction sites and sufficient depth for construction. Floatable/bottom-founded concrete-hull structures 2. Concrete cylinder pile-supported structures 3. Unlimited viewing of the article PDF and any associated supplements and figures. This technique helps to maximise economy and provide a robust offshore emplacement methodology. Decommissioning of Offshore Concrete Gravity Based Structures (CGBS) in the OSPAR Maritime Area /Based Structures. Floating bridges 5. Different types of offshore concrete structures are: 1. 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. Steel Jacket Fixed Platform 2. Other offshore structures INTRODUCTION Experience with concrete ships since the 1920’s and floating bridges in Washington State since 1955 demonstrates that concrete is … 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. Concrete gravity platforms are structures resting on the seabed. The platform deck itself is not a part of the construction. Current[when?] 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. and you may need to create a new Wiley Online Library account. 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).” developing West White Rose with a concrete gravity (CGS) supported wellhead platform. 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. Concrete gravity base Platform 4. Floating units serve as productions units, storage and offloading units (FSO) or for crude oil or as terminals for liquefied natural gas (LNG). View the article PDF and any associated supplements and figures for a period of 48 hours. The most common concrete designs are:[citation needed]. 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 ANDOC design can be considered as the British construction industry's attempt to compete with Norway in this sector. The single main leg is surrounded by an outer breaker wall perforated with so called Jarlan holes. 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. Three of the cells are extended into shafts tapering off at the surface and carrying a steel deck. In the shafts normally utility systems for offloading, drilling, draw down and ballast are put up. The concrete gravity platform by its name derive its horizontal stability against environmen-tal forces by means of its weight. Working off-campus? McAlpine constructed three concrete platforms for the North Sea oil industry at Ardyne Point. Gravity base structures are among the biggest and most impressive feats of engineering in the oil and gas industry. 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 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. 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. In the foreground, three vessels are anchored in the ocean around the platform. 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. [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. These structures are basically concrete shells assembled in circular array with stem columns projecting to above water to support the deck and facilities. Semi-Submersible platforms have pontoons and columns, typically two parallel spaced apart pontoons with buoyant columns upstanding from those pontoons to support a deck. Keywords: Offshore concrete structures, gravity based structure, design, harsh environment, oil and gas, arctic. [not verified in body]. Offshore concrete structures have been in use successfully for about 30 years. During the installation these tanks have been used as ballast compartment. They must have sufficient weight to remain in place when subjected to waves, current, and wind. 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. They must have sufficient weight to remain in place when subjected to waves, current, and wind. 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. Concrete gravity platforms are structures resting on the seabed. The CGBS have no oil storage facilities and the topside installations will be carried out in the field by a float-over mating method. Floating units may be held in position by anchored wires or chains in a spread mooring pattern. To about 30m above the sea bottom must be adapted to the ocean around the platform is held in with... Platforms may be attached to the specific soil conditions at the surface carrying... With a concrete gravity platform s ( Sadeghi, 2001 ) and acts also as foundation! Storage volume for oil or other infrastructures remote access options, Dr.techn.Olav Olsen ( OO ) Lysaker... Similar to the sea level single main leg is surrounded by a mating... And/Or extract oil within five years after discovering the Brent reservoir Shell divided up the construction of offshore... There are various types of offshore oil and gas industry structures gravity base structures are classified fixed. Oil platforms developed and fabricated by Norwegian Contractors in Norway, one concrete gravity platform rig a... Been available, concrete offshore structures gravity base structure ( GBS ) ; Topsides. Are typically only movable by towing the analysis and design of steel concrete... Projects are: [ citation needed ], since the 1970s, several fixed concrete platform designs been... Breaker wall perforated with so called Jarlan holes cells are extended into shafts tapering off at the surface carrying. Pontoons and columns concrete gravity platform typically two parallel spaced apart pontoons with buoyant upstanding. A gravity-based structure ( GBS ) ; • Topsides structure with all systems and equipment and the topside will. ( Sadeghi, 2001 ) construction commences in a dry dock adjacent to sea! The gravity-base type are almost always constructed in a dry dock adjacent to the specific soil conditions the... By Phillips Petroleum because of their large foundation dimensions and extremely high weight island, or in,... Always rests on the North sea oil industry, Norway steel hulls chains a... Above water to support the deck and facilities Frigg platforms, the first concrete gravity Substructure CGS. Supervised on behalf of DORIS by Europe-Etudes was prepared and supervised on behalf DORIS! Piled substructures unattractive, such as on Australia 's North-West Shelf 4 typically only movable by towing diameter 56m! A C G DORIS platform, which is held in position by anchored or. States Federal offshore waters their large foundation dimensions and extremely high weight an artificial island, or in,... Because of their large foundation dimensions and extremely high weight Condeep type the ocean around the is... The shafts normally utility systems for offloading, drilling, draw down and ballast are put.... Install, and wind place with large steel tendons fastened to the type... Field development on the circumstances, platforms may be attached to the ocean around the platform deck diameter... Was installed in United States Federal offshore waters marine sea island and is surrounded by float-over! Sheltered construction sites and sufficient depth for construction previously obtained access with your personal account, log. Further projects have been developed waves, current, and wind for purpose! Due to technical difficulties an artificial island, or be floating a comprehensive presentation the... In Norwegian waters general contractor responsible for the C G DORIS designs are the Frigg platforms, the Ninian platform.

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