Definition and Categories
The term "offshore" means "far from the coast" in English. Exploitation of hydrocarbons, oil and / or gas , is called "offshore" when in the open sea and is operated from platforms, fixed or floating anchored to the seabed
Platform supports the devices required for various phases of drilling and extraction of hydrocarbons and sometimes equipment to ensure a human presence on board. Some platforms also help transform the oil extracts so they are easier to carry. Moreover, it is possible to store them temporarily on floating units.
Technical or scientific operation
The process to exploit hydrocarbon deposits involves several sequential steps.
Earthquake Research deposits
One or more seismic vessels pull behind a series of air guns. They unload suddenly compressed air at high pressure in the marine environment in order to cause a seismic wave propagating into the subsoil. Depending on the type of rock encountered, these waves are more or less thought out and back faster or slower surface. These echoes are then detected by ultrasensitive microphones most often learned, too, by the seismic vessel.Computer processing can render a synthetic image in three dimensions distinguishing the different forms but also the geological nature of rocks, their porosity or fluids they contain.
The exploration phase
When a deposit is found, engineers use a floating platform. Usually equipped with a derrick (tower supporting the drilling of an oil well) and a drill bit (drill bit cone to break rocks), it is used to perform the drill floor Marine. It checks if there is enough oil in the tank to begin its operation. To control the pressure, is injected into the drilling rig by a "mud" dense that also trace the debris on the surface and cool the drill bit. After several weeks, the valves are adjusted wellhead and the floating platform is towed by vessels on another website. If the deposit is considered viable, a production platform or exploitation is built on land and towed to the site.
The exploitation phase
The tubes or hoses to go back to oil wells are connected to. A series of valves and gauges (instrument for measuring pressure) is then used to refine more precisely the desired flows.After several years of operation, the pressure starts to decline in the well. We then introduce another fluid under pressure in a well device. This liquid, often water, has a role to push the remaining oil up and allow to complete the operation.
The BOP (BOP wells) is a set of valves placed on the head of a wellbore. It is the security instrument allowing plug the well in case of extreme pressure from the reservoir to prevent leakage of oil.
Issues in relation to energy
If offshore presents a major potential, it is nevertheless exposed to significant issues in terms of cost and safety.
An oil carrier
In 2008, globally, it is estimated that 1 / 5th of oil reserves and over 40% of gas reserves from the seabed. In 2008, the French Oil Institute (IFP) said that offshore oil exploitation has provided 30% of global oil production and 27% of world gas production. Offshore is one of the few areas of access to new reserves of hydrocarbons with the exception of Canada's oil sands or shale gas Americans. Terrestrial reserves are mostly operated by national companies producing states like Saudi Arabia, Russia or Mexico. So in areas offshore that oil companies have achieved most of their major discoveries.
Technical and financial constraints
Drilling, it is operated using ships, fixed or mobile platforms, costs several times (3-4 times) the price of more expensive drilling on land. Generally, operation offshore is more expensive, partly because the deep sea exploration, but also complicates the operation of wells drilled.
Major players
Technology investments needed to exploit offshore remaining particularly expensive, only the majors (Total, Chevron, Exxon Mobil, Shell and BP) share the market among private companies.
However, they must now deal more with domestic companies producing countries such as Petrobras in Brazil. These companies, however, often depend on technology majors.
According to the U.S. Energy Information Administration, the national companies in 2007 controlled 52% of production and 88% of proven offshore resources.
Measurement Units and key figures
The share of the production of marine origin in the total world production of oil, which accounted for 10% (110 Mt) in 1960 rose to 30% in 2008 (1) .
In 2008, offshore operations provided 30% of global oil production and 27% of world gas production from the French Petroleum Institute (IFP).
The seabed to contain more than 70 million km2 of sedimentary basins with at least 30 million km 2 in more than 50 m of water.
The evolution of operating depths has been a gradual
- depth of 300 meters (considered deepwater) was achieved with the Cognac field in the Gulf of Mexico In 1979;
- depth of 1000 meters was completed in Brazil in the field south of Marlin in 1994;
- depth of 2000 meters was reached in the Gulf of Mexico Canyon Express project with the scope Aconcagua 2002;
- depth of 2200 meters was reached in offshore Brazil with the Tupi field in 2007.
Attendance area or application
Currently, there are oil exploration in the following regions:
- North Sea, located in Great Britain, Norway, Netherlands, Denmark;
- Persian Gulf;
- Gulf of Guinea such as Gabon and Nigeria; China Sea in the territorial waters of Vietnam, Malaysia and China;
- Mediterranean Sea, mainly off the coasts of North Africa;
- Caspian Sea;
- Coast of Brazil, whose huge Tupi field discovered in 2007;
- Gulf of Mexico along the U.S. coasts and in the Bay of Campeche (Mexico);
- Northwest coast and south-eastern Australia;
- Coast of Malaysia, Brunei and parts of the Indonesian archipelago;
- Canadian Atlantic coast, off Newfoundland (Hibernia, White Rose).
Past and present
In the aftermath of the Second World War, drilling in waters have increased more or less deep. In 1947, the first field began operation in the Gulf of Mexico. In 1973, the first oil shock has really boosted the offshore oil industry and many platforms have come into operation in the North Sea. Oil extracted in the seabed have become an alternative to dependence on Middle East.
This strategy proved successful, as it has uncovered many concerns, including the two largest fields discovered over the last twenty years, all categories: the Kashagan deposit, in the territorial waters of Kazakhstan Caspian Sea and, more recently, as Tupi, in the Santos Basin offshore Brazil.
Future
A compelling alternative
Despite the bad image caused by human or environmental accidents such as that of the platform "Deep Water, Horizon, offshore oil development seems inevitable. Representing nearly a fifth of oil reserves and 40% of gas reserves , offshore fields have become a necessity to meet global energy needs.
Security issues could change all that
Security issues are at the heart of development strategies offshore. Indeed the major accidents are often followed by human or environmental consequences very important. The crash of the Piper Alpha platform (explosion in 1988) has killed 167 people. The oil rig "Deep Water Horizon" suffered a violent explosion in the spring of 2010 leaving escape 5000 barrels per day, or 800,000 m 3 of oil. Well aware that what happened to one could happen to other players, oil companies and oil services are all impacted by the accident. This often results in the strengthening of security procedures and therefore the rising costs of operation.
Did you know?
The smallest country in the world is not the Vatican but the Principality of Sealand is located at sea about 10 miles from British shores. He is a former UK platform abandoned and located in territorial waters. In 1967, the era of pirate radio, a man named Roy Bates took over this island and declared as an independent nation with its own currency, flag and anthem. Issuing passports of many for several years, the Principality of Sealand illustrates the possibilities offered schedules the conversion of an oil platform. The website The Piracy Bay follower of the exchange of files uploaded recently in 2007 indeed tried to buy the island to set up its headquarters and take advantage of more flexible legislation.
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