An oil platform is a large structure used to house workers and machinery needed to drill and then produce oil and natural gas in the ocean. Depending on the circumstances, the platform may be attached to the ocean floor, consist of an artificial island, or be floating.
Generally, oil platforms are located on the continental shelf, though as technology improves, drilling and production in deeper waters becomes both feasible and profitable. A typical platform may have around thirty wellheads located on the platform and directional drilling allows reservoirs to be accessed at both different depths and at remote positions up to 5 miles (8 km) from the platform.
Many platforms also have remote wellheads attached by umbilical connections, these may be single wells or a manifold centre for multiple wells.
There are many types of platform which basically used by worldwide oil and gas operator such as fixed platform, semi-submersible platform, jack-up platform, drillship, floating production system (FPSO/FSO), compliant tower, spar platform and tension leg platform.
Tension leg platform (TLP) consists of floating rigs tethered to the seabed in a manner that eliminates most vertical movement of the structure. TLPS are used in water depths up to about 6,000 feet (2,000 m). The "conventional" TLP is a 4-column design which looks similar to a semisubmersible. Proprietary versions include the Seastar and MOSES mini TLPs; they are relatively low cost, used in water depths between 600 and 3,500 feet (200 and 1,100 m). Mini TLPs can also be used as utility, satellite or early production platforms for larger deepwater discoveries.
TLP is permanently moored by means of tethers or tendons grouped at each of the structure's corners. A group of tethers is called a tension leg. A feature of the design of the tethers is that they have relatively high axial stiffness (low elasticity), such that virtually all vertical motion of the platform is eliminated. This allows the platform to have the production wellheads on deck (connected directly to the subsea wells by rigid risers), instead of on the seafloor. This makes for a cheaper well completion and gives better control over the production from the oil or gas reservoir.
The first Tension Leg Platform was built for Conoco's Hutton field in the North Sea in the early 1980s. The hull was built in the dry-dock at Highland Fabricator's Nigg yard in the north of Scotland, with the deck section built nearby at McDermott's yard at Ardersier. The two parts were mated in the Moray Firth in 1984.
TLPs can be used as "stand alone full processing" platforms or simple "well head" platforms with processing undertaken at another facility such as an FPSO. In either case the TLP can be provided with drilling and/or workover capability
Recently Turnkey floating production provider MODEC has been awarded a 2007 Spotlight on New Technology award by the Offshore Technology Conference for a novel tension leg platform (TLP) design that has already been successfully installed offshore West Africa.
MODEC was singled out for its MOSES Self Stable Integrated Platform (SSIP) TLP, a next generation of TLP design, which MODEC describes as “an inherently stable platform that allows for quayside integration and commissioning of the topsides, as well as greater stability during transportation and during installation.”
As the offshore oil and gas industry strives to exploit reserves in deepwater, the MODEC TLP provides the technology, lower cost, and increased capability that is vital to continued offshore development.
The MODEC TLP is the next step in Tension Leg Platform design that retains the primary advantages of a TLP (low heave response) in a smaller, low-cost package. The MODEC TLP is not just a "scaled down" conventional TLP, it has been designed from the bottom up to improve on the efficiency of a conventional small TLP, while providing the same functionality at a lower cost. The MODEC TLP is able to achieve these results through efficient design approaches and innovative use of existing technology. Designs range in size from 3,000 to 50,000 tons displacement in water depths from 1,000 to deeper than 6,000 feet.
The key points of the MODEC TLP design include:
1.A more efficient hull design which minimizes the impact of wave loading, reduces the platform response in the "fatigue zone" and allows the tendon response to be "tuned" to obtain required platform response with a minimum of tension.
2.Low-cost tendon design which capitalizes on the lower maximum tendon tension and "fatigue zone" tendon response by utilizing standard mill run tubulars, threaded casing couplings and low cost top and bottom tendon connectors.
3.A well and riser system which utilizes standard 9 5/8" casing tie-back supported by a simple and economical short stroke riser tensioner.
4.A low-cost "jacket platform" deck design can be utilized, as hull structure and riser tension loads need not be reacted by the deck structure. This allows a much lighter deck structure to be used.
5.Well drilling or workover capability utilizing leased compact, lightweight, platform rigs.
6.Flexible installation method which can be completed with a wide variety of offshore equipment - SSDV, Multi-Service Vessels, or derrick barge, result in a more competitive installation cost.
OTC’s Spotlight Awards honor innovative technologies that are deemed to significantly impact the offshore exploration and production industry based on four criteria:
• New and Innovative: the technology must be less than two years old
• Proven: the technology must be proven, either through full-scale application or successful prototype testing
• Broad Interest: the technology must have a broad interest and appeal for the industry
• Significant Impact: the technology must provide significant benefits beyond existing technologies.
The MOSES SSIP TLP reportedly satisfies these criteria on several fronts. In terms of innovation, the hull configuration is comprised of a central base structure, four Tendon Support Structures (TSS) and four vertical columns. The base and TSS structures are located below the surface and provide a significant portion of the platform’s buoyancy. Each TSS is a rectangular pontoon structure. The columns are located further outboard, smaller than conventional TLP columns, and are rectangular in shape. Flowlines and SCRs are supported on sides of the columns, which enables easier SCR installation and future access.
A total of eight tendons, two at each end, are supported at the end of the TSS via top connectors on a porch arrangement. The tendons are connected at the sea bottom on piles via bottom connectors.
Because there is no need for supplemental stability modules, the design reportedly allows for considerable savings in offshore installation costs and schedule time and allows for the use of a wider range of installation vessels to install the platform. The SSIP TLP can reportedly support a variety of drilling or workover rigs and a large number of Top Tension Risers (TTR’s) and flowline risers. The TLP can also be used with wet and/or dry trees in harsh and mild environments.
The design of the open well bay arrangement also reportedly enhances well bay safety, increases the flexibility for the well arrangement, accommodates a large number of wells and allows drilling from any slot or a designated “drill center.”
Although the technology is still considered new by OTC’s definition, it has already proven itself offshore. The first applications of the MOSES SSIP TLP were the Okume E (Oveng”) and Okume F (Okume”), “twin” TLPs which were installed in early 2006 offshore Equatorial Guinea for Hess Corporation.
MODEC will receive its Spotlight on New Technology award, one of 14 to be handed out this year, at 4 pm Monday, 30 April, at the conference at Reliant Park in Houston.
References:
http://www.spe.org/
http://en.wikipedia.org/wiki/Tension-leg_platform
http://www.answers.com/topic/tension-leg-platform
http://www.modec.com/
Generally, oil platforms are located on the continental shelf, though as technology improves, drilling and production in deeper waters becomes both feasible and profitable. A typical platform may have around thirty wellheads located on the platform and directional drilling allows reservoirs to be accessed at both different depths and at remote positions up to 5 miles (8 km) from the platform.
Many platforms also have remote wellheads attached by umbilical connections, these may be single wells or a manifold centre for multiple wells.
There are many types of platform which basically used by worldwide oil and gas operator such as fixed platform, semi-submersible platform, jack-up platform, drillship, floating production system (FPSO/FSO), compliant tower, spar platform and tension leg platform.
Tension leg platform (TLP) consists of floating rigs tethered to the seabed in a manner that eliminates most vertical movement of the structure. TLPS are used in water depths up to about 6,000 feet (2,000 m). The "conventional" TLP is a 4-column design which looks similar to a semisubmersible. Proprietary versions include the Seastar and MOSES mini TLPs; they are relatively low cost, used in water depths between 600 and 3,500 feet (200 and 1,100 m). Mini TLPs can also be used as utility, satellite or early production platforms for larger deepwater discoveries.
TLP is permanently moored by means of tethers or tendons grouped at each of the structure's corners. A group of tethers is called a tension leg. A feature of the design of the tethers is that they have relatively high axial stiffness (low elasticity), such that virtually all vertical motion of the platform is eliminated. This allows the platform to have the production wellheads on deck (connected directly to the subsea wells by rigid risers), instead of on the seafloor. This makes for a cheaper well completion and gives better control over the production from the oil or gas reservoir.
The first Tension Leg Platform was built for Conoco's Hutton field in the North Sea in the early 1980s. The hull was built in the dry-dock at Highland Fabricator's Nigg yard in the north of Scotland, with the deck section built nearby at McDermott's yard at Ardersier. The two parts were mated in the Moray Firth in 1984.
TLPs can be used as "stand alone full processing" platforms or simple "well head" platforms with processing undertaken at another facility such as an FPSO. In either case the TLP can be provided with drilling and/or workover capability
Recently Turnkey floating production provider MODEC has been awarded a 2007 Spotlight on New Technology award by the Offshore Technology Conference for a novel tension leg platform (TLP) design that has already been successfully installed offshore West Africa.
MODEC was singled out for its MOSES Self Stable Integrated Platform (SSIP) TLP, a next generation of TLP design, which MODEC describes as “an inherently stable platform that allows for quayside integration and commissioning of the topsides, as well as greater stability during transportation and during installation.”
As the offshore oil and gas industry strives to exploit reserves in deepwater, the MODEC TLP provides the technology, lower cost, and increased capability that is vital to continued offshore development.
The MODEC TLP is the next step in Tension Leg Platform design that retains the primary advantages of a TLP (low heave response) in a smaller, low-cost package. The MODEC TLP is not just a "scaled down" conventional TLP, it has been designed from the bottom up to improve on the efficiency of a conventional small TLP, while providing the same functionality at a lower cost. The MODEC TLP is able to achieve these results through efficient design approaches and innovative use of existing technology. Designs range in size from 3,000 to 50,000 tons displacement in water depths from 1,000 to deeper than 6,000 feet.
The key points of the MODEC TLP design include:
1.A more efficient hull design which minimizes the impact of wave loading, reduces the platform response in the "fatigue zone" and allows the tendon response to be "tuned" to obtain required platform response with a minimum of tension.
2.Low-cost tendon design which capitalizes on the lower maximum tendon tension and "fatigue zone" tendon response by utilizing standard mill run tubulars, threaded casing couplings and low cost top and bottom tendon connectors.
3.A well and riser system which utilizes standard 9 5/8" casing tie-back supported by a simple and economical short stroke riser tensioner.
4.A low-cost "jacket platform" deck design can be utilized, as hull structure and riser tension loads need not be reacted by the deck structure. This allows a much lighter deck structure to be used.
5.Well drilling or workover capability utilizing leased compact, lightweight, platform rigs.
6.Flexible installation method which can be completed with a wide variety of offshore equipment - SSDV, Multi-Service Vessels, or derrick barge, result in a more competitive installation cost.
OTC’s Spotlight Awards honor innovative technologies that are deemed to significantly impact the offshore exploration and production industry based on four criteria:
• New and Innovative: the technology must be less than two years old
• Proven: the technology must be proven, either through full-scale application or successful prototype testing
• Broad Interest: the technology must have a broad interest and appeal for the industry
• Significant Impact: the technology must provide significant benefits beyond existing technologies.
The MOSES SSIP TLP reportedly satisfies these criteria on several fronts. In terms of innovation, the hull configuration is comprised of a central base structure, four Tendon Support Structures (TSS) and four vertical columns. The base and TSS structures are located below the surface and provide a significant portion of the platform’s buoyancy. Each TSS is a rectangular pontoon structure. The columns are located further outboard, smaller than conventional TLP columns, and are rectangular in shape. Flowlines and SCRs are supported on sides of the columns, which enables easier SCR installation and future access.A total of eight tendons, two at each end, are supported at the end of the TSS via top connectors on a porch arrangement. The tendons are connected at the sea bottom on piles via bottom connectors.
Because there is no need for supplemental stability modules, the design reportedly allows for considerable savings in offshore installation costs and schedule time and allows for the use of a wider range of installation vessels to install the platform. The SSIP TLP can reportedly support a variety of drilling or workover rigs and a large number of Top Tension Risers (TTR’s) and flowline risers. The TLP can also be used with wet and/or dry trees in harsh and mild environments.
The design of the open well bay arrangement also reportedly enhances well bay safety, increases the flexibility for the well arrangement, accommodates a large number of wells and allows drilling from any slot or a designated “drill center.”
Although the technology is still considered new by OTC’s definition, it has already proven itself offshore. The first applications of the MOSES SSIP TLP were the Okume E (Oveng”) and Okume F (Okume”), “twin” TLPs which were installed in early 2006 offshore Equatorial Guinea for Hess Corporation.
MODEC will receive its Spotlight on New Technology award, one of 14 to be handed out this year, at 4 pm Monday, 30 April, at the conference at Reliant Park in Houston.
References:
http://www.spe.org/
http://en.wikipedia.org/wiki/Tension-leg_platform
http://www.answers.com/topic/tension-leg-platform
http://www.modec.com/
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