Subsea technology

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Subsea technology involves fully submerged ocean equipment, operations, or applications, especially when some distance offshore, in deep ocean waters, or on the seabed. The term subsea is frequently used in connection with oceanography, marine or ocean engineering, ocean exploration, remotely operated vehicle (ROVs) autonomous underwater vehicles (AUVs), submarine communications or power cables, seafloor mineral mining, oil and gas, and offshore wind power.

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Oil and gas

Oil and gas fields reside beneath many inland waters and offshore areas around the world, and in the oil and gas industry the term subsea relates to the exploration, drilling and development of oil and gas fields in these underwater locations. [1] Under water oil fields and facilities are generically referred to using a subsea prefix, such as subsea well, subsea field, subsea project, and subsea developments.

Subsea oil field developments are usually split into Shallow water and Deepwater categories to distinguish between the different facilities and approaches that are needed. The term shallow water or shelf is used for very shallow water depths where bottom-founded facilities like jackup drilling rigs and fixed offshore structures can be used, and where saturation diving is feasible. Deepwater is a term often used to refer to offshore projects located in water depths greater than around 600 feet (180 m), [2] where floating drilling vessels and floating oil platforms are used, and remotely operated underwater vehicles are required as crewed diving is not practical.

Subsea completions can be traced back to 1943 with the Lake Erie completion at a 35 ft (11 m) water depth. The well had a land-type Christmas tree that required diver intervention for installation, maintenance, and flow line connections. [3] Shell completed its first subsea well in the Gulf of Mexico in 1961. [4]

Systems

Subsea oil production systems can range in complexity from a single satellite well with a flowline linked to a fixed platform, FPSO or an onshore installation, to several wells on a template or clustered around a manifold, and transferring to a fixed or floating facility, or directly to an onshore installation. [5]

Subsea production systems can be used to develop reservoirs, or parts of reservoirs, which require drilling of the wells from more than one location. Deep water conditions, or even ultradeep water conditions, can also inherently dictate development of a field by means of a subsea production system, since traditional surface facilities such as on a steel-piled jacket, might be either technically unfeasible or uneconomical due to the water depth. [5]

The development of subsea oil and gas fields requires specialized equipment. The equipment must be reliable enough to safeguard the environment and make the exploitation of the subsea hydrocarbons economically feasible. The deployment of such equipment requires specialized and expensive vessels, which need to be equipped with diving equipment for relatively shallow equipment work (i.e. a few hundred feet water depth maximum) and robotic equipment for deeper water depths. Any requirement to repair or intervene with installed subsea equipment is thus normally very expensive. This type of expense can result in economic failure of the subsea development.

Subsea technology in offshore oil and gas production is a highly specialized field of application with particular demands on engineering and simulation. Most of the new oil fields are located in deep water and are generally referred to as deepwater systems. Development of these fields sets strict requirements for verification of the various systems’ functions and their compliance with current requirements and specifications. This is because of the high costs and time involved in changing a pre-existing system due to the specialized vessels with advanced onboard equipment. A full-scale test (System Integration Test – SIT) does not provide satisfactory verification of deepwater systems because the test, for practical reasons, cannot be performed under conditions identical to those under which the system will later operate. The oil industry has therefore adopted modern data technology as a tool for virtual testing of deepwater systems that enables detection of costly faults at an early phase of the project. By using modern simulation tools, models of deepwater systems can be set up and used to verify the system's functions, and dynamic properties, against various requirements specifications. This includes the model-based development of innovative high-tech plants and system solutions for the exploitation and production of energy resources in an environmentally friendly way as well as the analysis and evaluation of the dynamic behavior of components and systems used for the production and distribution of oil and gas. Another part is the real-time virtual test of systems for subsea production, subsea drilling, supply above sea level, seismography, subsea construction equipment, and subsea process measurement and control equipment. [ citation needed ]

Offshore wind power

The power transmission infrastructure for offshore wind power utilizes a variety of subsea technologies for the installation and maintenance of submarine power transmission cables and other electrical energy equipment. [6] In addition, the monopile foundations of fixed-bottom wind turbines and the anchoring and cable structures of floating wind turbines are regularly inspected with a variety of shipborne subsea technology.

Underwater mining

Recent technological advancements have given rise to the use of remotely operated vehicles (ROVs) to collect mineral samples from prospective mine sites. Using drills and other cutting tools, the ROVs obtain samples to be analyzed for desired minerals. Once a site has been located, a mining ship or station is set up to mine the area. [7]

Seafloor mineral mining of seafloor massive sulfide deposits (so named for the sulfide molecules, not the deposit size) are a developing subsea mineral mining industry. Nautilus Minerals Inc. had begun to establish a new industry by commercially exploring and, in the future, planned to extract copper, gold, silver and zinc in its Solwara 1 Project. The project was establishing its operations 1 mile (1.6 km) beneath the ocean surface in the Bismarck Sea near Papua New Guinea. When fully underway the operation would have been the world’s first commercial deep sea mining project. [8] First production was expected to begin in 2017, but the company went bankrupt in 2019 after failing to secure funding for the project.

Remotely operated vehicles

Remotely Operated Vehicles (ROVs) are robotic pieces of equipment operated from afar to perform tasks on the sea floor. ROVs are available in a wide variety of function capabilities and complexities from simple "eyeball" camera devices, to multi-appendage machines that require multiple operators to operate or "fly" the equipment.

Other Professional Equipments used in installation of Sub Sea Telecommunication cable are specially designed crafts, modular barges, Water Pump along with Diving support and other accessories to seamlessly conduct installation operations in Deep Sea and Near Shore end, Rivers, Lakes. There are few professional companies in the world who own, operate such equipments and carry out operations worldwide on turnkey basis.

Energy harvesting and production

Subsea energy technologies are the subject of investigation using a number of technical strategies, none of which have yet been commercialized to become viable products or new energy industries. Energy sources under investigation include utility scale power production from ocean currents, such as the rapid currents found in the waters between the Florida Straits and Cape Hatteras. Research and projects are developing to harvest energy from hydrothermal vents to provide power for subsea ocean research instruments, developing autonomous vehicle recharge technologies, seabed sensor systems, and environmental research applications. Other investigations include harvesting energy from differences in temperature that occur with varied ocean depth, and microbial fuel cells that produce energy from organisms in ocean seafloor sediments.

Current methods for providing power for electric applications on offshore seabeds are limited to the use of batteries, power provided from generators on ships or platforms with fossil fuel generators, or for lower power requirements, wind, solar, or wave energy harvesting buoys.

Organizations

A number of professional societies and trade bodies are involved with the subsea industry around the world. Such groups include

Government agencies administer regulations in their territorial waters around the world. Examples of such government agencies are the Minerals Management Service (MMS, US), Norwegian Petroleum Directorate (NPD, Norway), and Health & Safety Executive (HSE, UK). The MMS administers the mineral resources in the US (using Code of Federal Regulations (CFR)) and provides management of all the US subsea mineral and renewable energy resources.

See also

Related Research Articles

<span class="mw-page-title-main">Oil platform</span> Offshore ocean structure with oil drilling and related facilities

An oil platform is a large structure with facilities to extract and process petroleum and natural gas that lie in rock formations beneath the seabed. Many oil platforms will also have facilities to accommodate the workers, although it is also common to have a separate accommodation platform linked by bridge to the production platform. Most commonly, oil platforms engage in activities on the continental shelf, though they can also be used in lakes, inshore waters, and inland seas. Depending on the circumstances, the platform may be fixed to the ocean floor, consist of an artificial island, or float. In some arrangements the main facility may have storage facilities for the processed oil. Remote subsea wells may also be connected to a platform by flow lines and by umbilical connections. These sub-sea facilities may include one or more subsea wells or manifold centres for multiple wells.

<span class="mw-page-title-main">Offshore construction</span> Installation of structures and facilities in a marine environment

Offshore construction is the installation of structures and facilities in a marine environment, usually for the production and transmission of electricity, oil, gas and other resources. It is also called maritime engineering.

<span class="mw-page-title-main">Remotely operated underwater vehicle</span> A tethered underwater mobile device operated by a remote crew

A remotely operated underwater vehicle (ROUV) or remotely operated vehicle (ROV) is a free-swimming submersible craft used to perform underwater observation, inspection and physical tasks such as valve operations, hydraulic functions and other general tasks within the subsea oil and gas industry, military, scientific and other applications. ROVs can also carry tooling packages for undertaking specific tasks such as pull-in and connection of flexible flowlines and umbilicals, and component replacement.

<span class="mw-page-title-main">Drilling rig</span> Integrated system to drill wells

A drilling rig is an integrated system that drills wells, such as oil or water wells, or holes for piling and other construction purposes, into the earth's subsurface. Drilling rigs can be massive structures housing equipment used to drill water wells, oil wells, or natural gas extraction wells, or they can be small enough to be moved manually by one person and such are called augers. Drilling rigs can sample subsurface mineral deposits, test rock, soil and groundwater physical properties, and also can be used to install sub-surface fabrications, such as underground utilities, instrumentation, tunnels or wells. Drilling rigs can be mobile equipment mounted on trucks, tracks or trailers, or more permanent land or marine-based structures. The term "rig" therefore generally refers to the complex equipment that is used to penetrate the surface of the Earth's crust.

<span class="mw-page-title-main">Drillship</span> Vessel fitted for offshore drilling

A drillship is a merchant vessel designed for use in exploratory offshore drilling of new oil and gas wells or for scientific drilling purposes. In recent years the vessels have been used in deepwater and ultra-deepwater applications, equipped with the latest and most advanced dynamic positioning systems.

<span class="mw-page-title-main">Marine engineering</span> Engineering and design of shipboard systems

Marine engineering is the engineering of boats, ships, submarines, and any other marine vessel. Here it is also taken to include the engineering of other ocean systems and structures – referred to in certain academic and professional circles as "ocean engineering".

<span class="mw-page-title-main">National Institute of Ocean Technology</span> Scientific organization in Tamil Nadu

The National Institute of Ocean Technology (NIOT) was established in November 1993 as an autonomous society under the Ministry of Earth Sciences in India. NIOT is managed by a Governing Council and is headed by a director. The institute is based in Chennai. The major aim of starting NIOT was to develop reliable indigenous technologies to solve various engineering problems associated with harvesting of non-living and living resources in India's exclusive economic zone, which is about two-thirds of the land area of India.

<span class="mw-page-title-main">Blowout (well drilling)</span> Uncontrolled release of crude oil and/or natural gas from a well

A blowout is the uncontrolled release of crude oil and/or natural gas from an oil well or gas well after pressure control systems have failed. Modern wells have blowout preventers intended to prevent such an occurrence. An accidental spark during a blowout can lead to a catastrophic oil or gas fire.

<span class="mw-page-title-main">Offshore drilling</span> Mechanical process where a wellbore is drilled below the seabed

Offshore drilling is a mechanical process where a wellbore is drilled below the seabed. It is typically carried out in order to explore for and subsequently extract petroleum that lies in rock formations beneath the seabed. Most commonly, the term is used to describe drilling activities on the continental shelf, though the term can also be applied to drilling in lakes, inshore waters and inland seas.

"Offshore", when used in relation to hydrocarbons, refers to operations undertaken at, or under the, sea in association with an oil, natural gas or condensate field that is under the seabed, or to activities carried out in relation to such a field. Offshore is part of the upstream sector of the oil and gas industry.

<i>Deepwater Horizon</i> Former offshore oil drilling rig

Deepwater Horizon was an ultra-deepwater, dynamically positioned, semi-submersible offshore drilling rig owned by Transocean and operated by BP. On 20 April 2010, while drilling at the Macondo Prospect, a blowout caused an explosion on the rig that killed 11 crewmen and ignited a fireball visible from 40 miles (64 km) away. The fire was inextinguishable and, two days later, on 22 April, the Horizon sank, leaving the well gushing at the seabed and turning into the largest marine oil spill in history.

<span class="mw-page-title-main">Bouri Field</span> Libyan offshore oil field

The Bouri Offshore Field is part of Block NC-41, which is located 120 kilometers (75 mi) north of the Libyan coast in the Mediterranean Sea. It was first discovered in 1976 at a depth of 8,700 feet (2,700 m) and is estimated to contain 4.5 billion barrels (720,000,000 m3) in proven recoverable crude oil reserves and 3.5 trillion cubic feet (99 km3) of associated natural gas with an annual production potential of 6 billion m³. Bouri is considered the largest producing oilfield in the Mediterranean.

Oceaneering International, Inc. is a subsea engineering and applied technology company based in Houston, Texas, U.S. that provides engineered services and hardware to customers who operate in marine, space, and other environments.

Deepwater drilling, or deep well drilling, is the process of creating holes in the Earth's crust using a drilling rig for oil extraction under the deep sea. There are approximately 3400 deepwater wells in the Gulf of Mexico with depths greater than 150 meters.

<span class="mw-page-title-main">Grup Servicii Petroliere</span>

Grup Servicii Petroliere is a Romanian company providing offshore integrated services for oil and gas industry. The company, established in 2004, is a member of UPETROM Group.

<span class="mw-page-title-main">Oil and gas industry in the United Kingdom</span>

The oil and gas industry plays a central role in the economy of the United Kingdom. Oil and gas account for more than three-quarters of the UK's total primary energy needs. Oil provides 97 per cent of the fuel for transport, and gas is a key fuel for heating and electricity generation. Transport, heating and electricity each account for about one-third of the UK's primary energy needs. Oil and gas are also major feedstocks for the petrochemicals industries producing pharmaceuticals, plastics, cosmetics and domestic appliances.

<span class="mw-page-title-main">Cameron International</span> American oilfield services company

Cameron International Corporation (formerly Cooper Cameron Corporation (CCC) and Cooper Oil Tool, Cameron Iron Works) though now operating under Schlumberger, is a global provider of pressure control, production, processing, and flow control systems as well as project management and aftermarket services for the oil and gas and process industries. Cameron was acquired by Schlumberger (SLB) in 2016, and now operates as 'Cameron, an SLB Company.' At the start of the SLB acquisition in 2015, Cameron employed approximately 23,000 people and delivered $9.8 billion in revenue.

<span class="mw-page-title-main">Suction caisson</span> Open bottomed tube anchor embedded and released by pressure differential

Suction caissons are a form of fixed platform anchor in the form of an open bottomed tube embedded in the sediment and sealed at the top while in use so that lifting forces generate a pressure differential that holds the caisson down. They have a number of advantages over conventional offshore foundations, mainly being quicker to install than deep foundation piles and being easier to remove during decommissioning. Suction caissons are now used extensively worldwide for anchoring large offshore installations, like oil platforms, offshore drillings and accommodation platforms to the seafloor at great depths. In recent years, suction caissons have also seen usage for offshore wind turbines in shallower waters.

<span class="mw-page-title-main">GE Oil and Gas</span> Division of General Electric

GE Oil & Gas was the division of General Electric that owned its investments in the petroleum industry. In July 2017, this division was merged with Baker Hughes.

Ocean development refers to the establishing of human activities at sea and use of the ocean, as well as its governance.

References

  1. ↑ "The Subsea Industry". Subsea oil and gas directory for subsea industry professionals. Retrieved 27 September 2016.
  2. ↑ Oil field Glossary - Deepwater Play : http://www.glossary.oilfield.slb.com/Display.cfm?Term=deep%2Dwater%20play
  3. ↑ (2010) International Petroleum Encyclopedia. Retrieved November 09, 2010, from http://www.pennenergy.com/index/petroleum/international-petroleum-encyclopedia/display/114882/ipes/online-research-center/volume-1999/issue-1/encyclopedia/special-features/new-features-improve-flexibility-of-subsea-well-completions.html
  4. ↑ 60 Years in the Gulf of Mexico, E&P Supplement, Hart Publishing, November 2007
  5. ↑ Global Marine Systems on the future of offshore wind cabling Archived 2010-05-05 at the Wayback Machine , Wind Energy Update, 2009-09-10, accessed 2011-07-30.
  6. ↑ Treasure on the ocean floor, Economist 381, no. 8506:10, EBSCOhost, (accessed January 19, 2010).
  7. ↑ Jamasmie, Cecilia (7 April 2015). "Nautilus Minerals resumes undersea mining exploration" . Retrieved 22 September 2016.
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