New Platforms Design Withstand North Sea Conditions

The pressure to reduce the cost of new developments has never been greater for North Sea operators. The combination of low oil prices, decreased North Sea development opportunities and increased competition from the U.S. shale industry means the industry is being forced to adapt to new ideas.

One development concept that is starting to gain traction is the use of low-cost wellhead platforms for the development of small satellite fields. These are typically newly discovered fields close to an established host platform, which can provide control and power and also carry out fluid processing. Although wellhead platforms have long been a favorite in the shallow waters of the southern North Sea, up until now the preferred option for the development of satellite fields in deeper water has been to use a subsea manifold with a tieback to the host facility. Subsea manifolds are tried, tested and trusted, but WorleyParsons has carried out several studies showing that subsea manifolds don’t necessarily provide the best value solution for a multiple well development. The difficulties and additional costs associated with maintenance and future well intervention operations can all contribute to increased costs over the lifetime of a project.

WorleyParsons has accumulated a reference list of more than 500 installations that are currently operating throughout the world, and its team has combined its experience with ideas borrowed from the shale industry—where standardization and modularization of equipment is the key to low-cost field development. The company has come up with a new concept in wellhead platforms suitable for installation in deeper water and able to withstand North Sea conditions.

The new design uses piled foundations, can be deployed in water depths of up to 120 m (394 ft) and provides space for a maximum of 12 well slots. No accommodation has been provided for personnel, who will gain access for four monthly maintenance visits by vessels equipped with a “walk-to-work” gangway. The platform design includes a 5-tonne crane and sufficient deck space to allow full access for future well intervention. WorleyParsons also has designed the new platform for construction in its covered yard near Stavanger, Norway, with one flat side to permit installation by either barge launch or jackup platform to widen the choice of installation contractor.

The platform is designed with a “design once, build many” approach to capture economies of scale and efficiencies more closely associated with a production line than a North Sea construction yard. The design borrows from the philosophies that WorleyParsons has previously followed in the Persian Gulf and Gulf of Thailand and uses a minimum number of different profiles to reduce procurement and stockholding costs.

Topsides and jacket weights are comparable to more traditional North Sea designs at about 650 tonnes and 3,500 tonnes, respectively, for a 100-m (328-ft) water depth platform, with almost all of the topsides and much of the jacket being identical for any platform regardless of water depth. However, there is scope for significant savings in project schedule by both reducing setup times and by allowing construction to start in parallel with detailed design. The design is so standardized that water depth, seabed conditions and well slot arrangement are the only pieces of information required to completely define an individual platform, further reducing project schedule and minimizing construction risk.

WorleyParsons sees an immediate market for at least 20 lowcost modularized platforms in the Norwegian sector of the North Sea alone and is talking to several operators who have been carrying out studies to assess their viability. They also see applications in U.K. waters, where the upcoming 30th licensing round will be targeting small pool discoveries that will require especially low-cost development schemes.

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Fixed Platform for Oil-Gas drilling and Production

A fixed platform is a permanent structure attached to the bottom of the ocean, often for the purpose of offshore oil extraction. Most of the work space of this platform is lifted over the surface of the sea from rigid steel or concrete supports. This rules a fixed platform with mobile platforms floating on the surface of the sea and anchored to the bottom of the ocean by more or less flexible moorings. Fixed platforms are typically deployed in water less than 1,700 feet (520 meters) in depth, with deeper drilling activities requiring more complex mobile platforms.

The first productive offshore oil wells were drilled in Ohio Grand Lake St. Marys State Park in 1891, using fixed platforms set on wooden piles at the bottom of the lake. In 1947, the first fixed platform drilling rig located beyond the view of the earth was built in the Gulf of Mexico. Fixed platforms were the most common method of offshore drilling for most of the 20th century, although the first mobile drilling rigs were operating since the early 1930s. Due to their high stability, depth limitation, and high, modern cost Fixed platform drilling rigs are limited to long-run drilling operations in shallow waters.

Fixed platforms are connected directly to the bottom of the ocean by a structural support known as a jacket. The first jackets consisted of concrete foundation poles, while modern deep water jackets are the tough towers of steel tubular supports. The base of a coating can be several times larger than the top, and are often driven deep into the ocean floor mud for support. The jackets are either partially or entirely built to the ground and shipped to the deck's position on bargain tugboats. Once there, they dropped to the bottom of the ocean with the help of ROV, and pushed them into position using bats mounted on barges.

The bridges that form the work space of a platform are generally built on sheltered yards or bays. While the first barges were towed on barges, many modern bridges are built to float during transit. They got to the top of the waiting jacket using hydraulic jacks or barges, and are usually quite high above the floating line to avoid all but the biggest waves. Bridges can be up to 200 feet (60 meters) in diameter, and consist of several levels of work and living space.

If a fixed platform is near the shore, you can pump oil directly from the onshore drilling site of storage facilities through gas pipelines provided along the ocean floor. In the case of drilling operations far from the ground, the platform must include large reservoirs containing the oil as long as it can be transferred to a tanker. Storage tanks are often located below the floating line, where they serve as a ballast to help the platform withstand the power of waves and currents.

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Investment for Offshore Rig

Offshore drilling is a technology-heavy industry, and if you want to invest in companies that work in this space of goods, you want to be familiar with the associated terminology.

Since offshore drilling can take place in unforgiving places, companies need to implement specific boats for specific drilling projects. These ships are among the most technologically advanced man-made structures. Some ships are designed to withstand strong winds and high waves. Others are more suitable for exploratory projects in shallow waters and need to move from one place to another quickly.

Here are the names of some of these pots you can expect to come across as you start investing in offshore drilling companies:

• Barge drilling: The drilling barge is one of the most agile vessels on the market. It is a floating device usually towed by a tug to hit puncture positions. The drilling barge is mainly used in the inland, still shallow waters, such as rivers, lakes and swamps.
• Jack-up rig: The rig jack-up is a hybrid vessel that is part floating barge, part drilling platform. The jack-up drilling rig is towed to the desired position, usually open, shallow waters where its three "legs" are lowered and "jacked" towards the seabed. When the legs are fixed, the drilling platform is raised to the desired levels to allow for safe drilling.
• Submarine Rig: The submersible rig is similar to the rig jack-up, as it is mainly used for shallow water drilling and is fixed to the bottom of the sea.
• Semi-submersible plant: sometimes referred to as a seed, this structure is a stunt of modern technological development. It's like a submersible, except that it has the ability to pierce deep in adverse weather conditions and not forgive. 
• The drilling platform is high and sits on top of a floating structure that is semi-submerged in water (hence the name) and secured by large dowels that can weigh up to 10 tons each.
• Drill Ship: The drilling vessel is essentially a ship with a drilling deck. It is perhaps the most versatile drilling tool as it can easily be sent to remote offshore locations, including deepwater drilling.
• Offshore Oil Platform: When one of the previous vessels discovers a commercially viable offshore oilfield, a company may decide to build a permanent platform to exploit this discovery. Insert the offshore oil platform. These facilities are a spectacle to see and are really from the floating city man. They are staffed, they include homes, and are often equipped with shelter. They are ideal for difficult conditions in deep waters.

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