Deepwater drilling

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Deepwater drilling, [1] or deep well drilling, [2] 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. [3] [ full citation needed ]

Contents

Deepwater drilling has not been technologically or economically feasible for many years, but with rising oil prices,[ when? ] more companies are investing in this sector. [4] Major investors include Halliburton, Diamond Offshore, Transocean, Geoservices, and Schlumberger. The deepwater gas and oil market has been back on the rise since the 2010 Deepwater Horizon disaster, with total expenditures of around US$35 billion per year in the market and total global capital expenditures of US$167 billion in the past four years. [5] Industry analysis by business intelligence company Visiongain estimated in 2011 that total expenditures in global deepwater infrastructure would reach US$145 billion. [6]

A HowStuffWorks article explains how and why deepwater drilling is practiced:

Not all oil is accessible on land or in shallow water. You can find some oil deposits buried deep under the ocean floor. ... Using sonic equipment, oil companies determine the drilling sites most likely to produce oil. Then they use a mobile offshore drilling unit (MODU) to dig the initial well. Some units are converted into production rigs, meaning they switch from drilling for oil to capturing oil once it's found. Most of the time, the oil company will replace the MODU with a more permanent oil production rig to capture oil. ...The MODU's job is to drill down into the ocean's floor to find oil deposits. The part of the drill that extends below the deck and through the water is called the riser. The riser allows for drilling fluids to move between the floor and the rig. Engineers lower a drill string – a series of pipes designed to drill down to the oil deposit – through the riser. [7]

In the Deepwater Horizon oil spill of 2010, a large explosion occurred, killing workers and spilling oil into the Gulf of Mexico while a BP oil rig was drilling in deep waters.

The expansion of deepwater drilling is happening despite accidents in offshore fields ... Despite the risks, the deepwater drilling trend is spreading in the Mediterranean and off the coast of East Africa after a string of huge discoveries of natural gas. ... The reason for the resumption of such drilling, analysts say, is continuing high demand for energy worldwide. [8]

History

A Chinese ceramic model of a well with a water pulley system, excavated from a tomb of the Han Dynasty (202 BC - 220 AD) period Model well, burial find, China, Han dynasty, 206 BC to 220 AD, earthenware - Ostasiatiska museet, Stockholm - DSC09578.JPG
A Chinese ceramic model of a well with a water pulley system, excavated from a tomb of the Han Dynasty (202 BC - 220 AD) period

Some of the earliest evidence of water wells are located in China. The Chinese discovered and made extensive use of deep drilled groundwater for drinking. The Chinese text The Book of Changes , originally a divination text of the Western Zhou dynasty (1046 -771 BC), contains an entry describing how the ancient Chinese maintained their wells and protected their sources of water. [9] Archaeological evidence and old Chinese documents reveal that the prehistoric and ancient Chinese had the aptitude and skills for digging deep water wells for drinking water as early as 6000 to 7000 years ago. A well excavated at the Hemedu excavation site was believed to have been built during the Neolithic era. [10] [11] The well was cased by four rows of logs with a square frame attached to them at the top of the well. 60 additional tile wells southwest of Beijing are also believed to have been built around 600 BC for drinking and irrigation. [10] [12]

Types of deepwater drilling facilities

Drilling in deep waters can be performed by two main types of mobile deepwater drilling rigs: semi-submersible drilling rigs and drillships. Drilling can also be performed from a fixed-position installation such as a fixed platform, or a floating platform, such as a spar platform, a tension-leg platform, or a semi-submersible production platform.

  1. Fixed Platform - A Fixed Platform consists of a tall, (usually) steel structure that supports a deck. Because the Fixed Platform is anchored to the sea floor, it is very costly to build. This type of platform can be installed in water depth up to 500 meters (1,600 feet).
  2. Jack-Up Rig - Jack-up rigs are mobile units with a floating hull that can be moved around; once they arrived at the desired location, the legs are lowered to the seafloor and locked into place. Then the platform is raised up out of the water. That makes this type of rig safer to work on because weather and waves are not an issue.
  3. Compliant Tower Platform - A compliant tower is a particular type of fixed platform. Both are anchored to the seafloor, and both workplaces are above the water surface. However, the compliant tower is taller and narrower and can operate up to 1 kilometer (3,000 feet) water depth.
  4. Semi-Submersible Production Platform - This platform is buoyant, meaning the bulk of it is floating above the surface. However, the well head is typically located on the seafloor, so extra precautions must be taken to prevent a leak. A contributing cause to the oil spill disaster of 2010 was a failure of the leak-preventing system. These rigs can operate anywhere from 200 to 2,000 meters (660 to 6,560 feet) below the surface.
  5. Tension-Leg Platform - The Tension-leg Platform consists of a floating structure, held in place by tendons that run down to the seafloor. These rigs drill smaller deposits in narrower areas, meaning this is a low-cost way to get a little oil, which attracts many companies. These rigs can drill anywhere from 200 to 1,200 meters (660 to 3,940 feet) below the surface.
  6. Subsea System - Subsea Systems are actually wellheads, which sit on the seafloor and extract oil straight from the ground. They use pipes to force the oil back up to the surface, and can siphon oil to nearby platform rigs, a ship overhead, a local production hub, or even a faraway onshore site. This makes the Subsea system very versatile and a popular choice for companies.
  7. Spar Platform - Spar Platforms use a large cylinder to support the floating deck from the seafloor. On average, about 90% of the Spar Platform's structure is underwater. Most Spar Platforms are used up to depths of 1 kilometer (3,000 feet), but new technology can extend them to function up to 3,500 meters (11,500 feet) below the surface. That makes it one of the deepest drilling rigs in use today. [13]

2010 Deepwater Horizon oil spill

On 20 April 2010, a BP deepwater oil rig (Deepwater Horizon) exploded, killing 11 and releasing 750,000 cubic meters (200 million gallons) of oil into the Gulf of Mexico. With those numbers, many scientists consider this disaster to be one of the worst environmental disasters in the history of the US. [14]

A large number of animal deaths have resulted from the release of the oil. A Center study estimates that over 82,000 birds, about 6,000 sea turtles, and nearly 26,000 marine mammals were killed from either the initial explosion or the oil spill.

See also

General
Offshore drilling, Well drilling, Shallow water drilling, Extraction of petroleum, Age of Oil, Fossil fuel drilling (disambiguation), Energy development, Hubbert peak theory
Other
2010 United States deepwater drilling moratorium, Submersible pump, IntelliServ, Petroleum industry in Mexico, Deepwater Horizon
People
Michael Klare, Jason Leopold

Related Research Articles

Oil platform Large offshore structure with oil drilling and related facilities

An oil platform, oil rig, offshore platform, or oil and/or gas production 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 contain facilities to accommodate their workforce, although it is also common for there to be a separate accommodation platform bridge linked 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 solutions may consist of one or more subsea wells or of one or more 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">Semi-submersible platform</span> Marine vessel used in offshore roles wtth good stability and seakeeping

A semi-submersible platform is a specialised marine vessel used in offshore roles including as offshore drilling rigs, safety vessels, oil production platforms, and heavy lift cranes. They have good ship stability and seakeeping, better than drillships.

Tension-leg platform Type of offshore platform used in production of oil or gas

A tension-leg platform (TLP) or extended tension leg platform (ETLP) is a vertically moored floating structure normally used for the offshore production of oil or gas, and is particularly suited for water depths greater than 300 metres and less than 1500 metres. Use of tension-leg platforms has also been proposed for offshore wind turbines.

The Atlantis oil field is the third largest oil field in the Gulf of Mexico. The field was discovered in 1998 and is located at the Green Canyon blocks 699, 700, 742, 743, and 744 in United States federal waters in the Gulf of Mexico about 130 miles (210 km) from the coast of Louisiana. The oil field lies in water depths ranging from 4,400 to 7,100 feet. The subsea structure of Atlantis has long been the target of safety critics.

<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">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.

Offshore drilling 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.

Subsea is fully submerged ocean equipment, operations or applications, especially when some distance offshore, in deep ocean waters, or on the seabed. The term 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.

"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 causing the largest marine oil spill in history.

A submersible drilling rig is a marine vessel design that can be floated to location and lowered onto the sea floor for offshore drilling activities.

Drilling riser

A drilling riser is a conduit that provides a temporary extension of a subsea oil well to a surface drilling facility. Drilling risers are categorised into two types: marine drilling risers used with subsea blowout preventer (BOP) and generally used by floating drilling vessels; and tie-back drilling risers used with a surface BOP and generally deployed from fixed platforms or very stable floating platforms like a spar or tension leg platform (TLP).

The Macondo Prospect is an oil and gas prospect in the United States Exclusive Economic Zone of the Gulf of Mexico, off the coast of Louisiana. The prospect was the site of the Deepwater Horizon drilling rig explosion in April 2010 that led to a major oil spill in the region from the first exploration well, named itself MC252-1, which had been designed to investigate the existence of the prospect.

<i>Deepwater Horizon</i> explosion 2010 oil disaster in the Gulf of Mexico

The Deepwater Horizon drilling rig explosion was an April 20, 2010 explosion and subsequent fire on the Deepwater Horizon semi-submersible mobile offshore drilling unit, which was owned and operated by Transocean and drilling for BP in the Macondo Prospect oil field about 40 miles (64 km) southeast off the Louisiana coast. The explosion and subsequent fire resulted in the sinking of the Deepwater Horizon and the deaths of 11 workers; 17 others were injured. The same blowout that caused the explosion also caused an oil well fire and a massive offshore oil spill in the Gulf of Mexico, considered the largest accidental marine oil spill in the world, and the largest environmental disaster in United States history.

<i>Deepwater Nautilus</i>

Deepwater Nautilus is an ultra-deepwater, semi-submersible offshore drilling rig.

Perdido (oil platform) Deepwater oil platform

Perdido (spanish for lost) is the deepest floating oil platform in the world at a water depth of about 2450 meters (8040 feet) operated by the Shell Oil Company in the Gulf of Mexico. At 267 meters, the above water portion of the structure is almost as tall as the Eiffel Tower. The platform is located in the Perdido fold belt which is a rich discovery of crude oil and natural gas. The Perdido spar began production in 2010 and its peak production is 100,000 barrels of oil equivalent (ca. 16,000 m3/d) and 200 million cubic feet of gas per day (ca. 5.7*106 m3/d).

An Emergency Disconnect Package (EDP) is a piece of equipment used in the drilling and work-over of deep sea oil & gas wells, by Mobile Offshore Drilling Rigs (MODU's) and Well Intervention Vessels (WIV's). The EDP is designed for use in an emergency, when the MODU or WIV needs to quickly disconnect, and move away from the oil/gas well that it is drilling or working-over. Examples of when this might be necessary include unexpected extreme weather that exceeds the MODU/Vessel's capability to maintain its position.

The Helix fast-response system (HFRS) is a deep-sea oil spill response plan licensed by HWCG LLC, a consortium of 16 independent oil companies, to respond to subsea well incidents. Helix Energy Solutions Group designed the Helix fast-response system based on techniques used to contain the 2010 Gulf of Mexico oil spill. On February 28, 2011 the drilling moratorium imposed as a result of the spill ended when the United States Department of the Interior approved the first drilling permit based on the availability of the HFRS to offshore oil companies.

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

References

  1. Leffler, William L.; Pattarozzi, Richard; Sterling, Gordon (2011). Deepwater Petroleum Exploration & Production: A Nontechnical Guide. PennWell Books. ISBN   978-0878148462.
  2. Jeffery, Walter Henry (1921). Deep Well Drilling: The Principles and Practices of Deep Well Drilling, and a Hand Book of Useful Information for the Well Driller. W. H. Jeffery Company.
  3. "Maps and GIS Data | Bureau of Ocean Energy Management".
  4. The Deepwater Ultra Deepwater Exploration Production Market 2013-2023. visiongain. January 2, 2013. Retrieved 21 September 2013.
  5. "The World Deepwater Market Report 2010-2014". Archived from the original on 2014-01-09. Retrieved 2014-01-09.
  6. The Deepwater Ultra Deepwater Market 2011-2021. visiongain. May 31, 2011. Archived from the original on June 8, 2011. Retrieved 21 September 2013.
  7. Freudenrich, Ph.D, Craig; Strickland, Jonathan (12 April 2001). "How Oil Drilling Works" . Retrieved 21 September 2013.
  8. Krauss, Clifford; Broder, John M. (2012-03-04). "Deepwater Oil Drilling Picks Up Again as BP Disaster Fades". New York Times.
  9. Kuhn, Oliver (2004-06-30). "Ancient Chinese Drilling". Canadian Society of Exploration Geophysicists. 29 (6).
  10. 1 2 Chang, Mingteh (2012). Forest Hydrology: An Introduction to Water and Forests (3rd ed.). CRC Press (published November 1, 2012). p. 31. ISBN   978-1439879948.
  11. Angelakis, Andreas N.; Mays, Larry W.; Koutsoyiannis, Demetris; Mamassis, Nikos (2012). Evolution of Water Supply Through the Millennia. Iwa Publishing (published January 1, 2012). pp. 202–203. ISBN   978-1843395409.
  12. Koon, Wee Kek (July 25, 2015). "How the ancient Chinese looked after their drinking water". South China Morning Post.
  13. http://www.mnn.com/earth-matters/energy/stories/types-of-offshore-oil-rigs}%5B%5D
  14. "Exxon, be Gone".

External articles