Jakas reklama 

 

 This article needs additional citations for verification.
Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (March 2007)

North Sea oil refers to oil and natural gas (hydrocarbons) produced from oil reservoirs beneath the North Sea. In the oil industry, "North Sea" often refers to a larger geographical set, including areas such as the Norwegian Sea and the UK "Atlantic Margin" (west of Shetland) not, strictly speaking, part of the North Sea.

Brent crude is still used today as a standard benchmark for pricing oil, although the contract now refers to a blend of oils from fields in the northern North Sea.

Contents

History

1851-1963

Commercial extraction of oil on the shores of the North Sea dates back to 1851, when James Young retorted oil from torbanite (boghead coal, or oil shale) mined in the Midland Valley of Scotland.1 Across the sea in Germany, oil was found in the Wietze field near Hanover in 1859, leading to the discovery of 70 more fields, mostly in Lower Cretaceous and Jurassic reservoirs, producing a combined total of around 8000 barrels per day.1

Gas was found by chance in a water well near Hamburg in 1910, leading to minor gas discoveries in Zechstein dolomites elsewhere in Germany.1 In England, BP discovered gas in similar rservoirs in the Eskdale anticline in 1938, and in 1939 they found commercial oil in Carboniferous rocks at Eakring in Nottinghamshire.1 Discoveries elsewhere in the East Midlands lifted production to 2500 barrels per day, and a second wave of exploration from 1953 to 1961 found the Gainsborough field and 10 smaller fields.1

The Netherlands' first oil shows were seen in a drilling demonstration at De Mient during the 1938 World Petroleum Congress at The Hague.1 Subsequent exploration led to the 1943 discovery by Exploratie Nederland, part of the Royal Dutch/Shell company Bataafsche Petroleum Maatschappij, of oil under the Dutch village of Schoonebeek, near the German border.2 NAM found the Netherlands' first gas in Zechstein carbonates at Coevorden in 1948.2 1952 saw the first exploration well in the province of Groningen, Haren-1, which was the first to penetrate the Lower Permian Rotliegendes sandstone that is the main reservoir for the gas fields of the southern North Sea, although in Haren-1 it contained only water.3 The Ten Boer well failed to reach target depth for technical reasons, but was completed as a minor gas producer from the Zechstein carbonates.3 The Slochteren-1 well found gas in the Rotliegendes in 1959,3 although the full extent of what became known as the Groningen field was not appreciated until 1963 - it is currently estimated at ~96tcf (2,700×109 m³) recoverable gas reserves.2 Smaller discoveries to the west of Groningen followed.

1964-2008

Following this success, exploration of the similar rocks offshore was a natural progression. Licensing regulations for Dutch waters were not finalised until 1967, but the UK Continental Shelf Act came into force in May 1964, setting the scene for seismic and the first well later that year. It and a second well on the Mid North Sea High were dry, as the Rotliegendes was absent, but BP's Sea Gem rig struck gas in the West Sole field in September 1965.4 The celebrations were short-lived, as part of the rig collapsed as it mobilised from the discovery well, and it sank with the loss of 13 lives.4 Larger gas finds followed in 1966 - Leman Bank, Indefatigable and Hewett, but by 1968 companies had lost interest in further exploration of the British sector, a result of a ban on gas exports and low prices offered by the only buyer, British Gas.4 West Sole came onstream in May 1967.4

The situation was transformed in December 1969, when Phillips Petroleum discovered oil in Chalk of Danian age at Ekofisk, in Norwegian waters in the central North Sea.4 The same month, Amoco discovered the Montrose field about 135 miles east of Aberdeen.4 BP had been awarded several licences in the area in the second licensing round late in 1965, but had been reluctant to work on them.4 The discovery of Ekofisk prompted them to drill what turned out to be a dry hole in May 1970, followed by the discovery of the giant Forties oilfield in October 1970.4 The following year, Shell Expro discovered the giant Brent oilfield in the northern North Sea east of Shetland. Oil production started from the Argyll field (now Ardmore) in June 19755 followed by Forties in November of that year.6

Volatile weather conditions in Europe's North Sea have made drilling particularly hazardous, claiming many lives. The conditions also make extraction a costly process; by the 1980s costs for developing new methods and technologies to make the process both efficient and safe, far exceeded NASA's budget to land a man on the moon. 7 The exploration of the North Sea has been a story of continually pushing the edges of the technology of exploitation (in terms of what can be produced) and later the technologies of discovery and evaluation (2-D seismic, followed by 3-D and 4-D seismic; sub-salt seismic; immersive display and analysis suites and supercomputing to handle the flood of computation required).citation needed

The largest field discovered in the past 25 years is Buzzard, found in June 2001 with producible reserves of almost 400m barrels and an average output of 180,000-190,000 barrels per day8. While significant, this is less than the amount of oil consumed globally in a single week.9

Licensing

Five countries are involved in oil production in North Sea. All operate a tax and royalty licensing regime. The respective sectors are divided by median lines agreed in the late 1960s:

Reserves and production

The British and Norwegian sections hold most of the remainder of the large oil reserves. Estimates say that in the Norwegian section alone lie 54% of the sea's oil reserves and 45% of its gas reserves.10 More than half of the North Sea oil reserves have been extracted, according to official sources in both Norway and the UK. For Norway, the NPD 11 gives 4601 million cubic meters (corresponding to 29 billion barrels) for the Norwegian north sea alone (excluding smaller reserves in Norwegian sea and Barents Sea) ultimate of which 2778 (60%) already produced to January 2007. UK sources gives a range of reserve estimate, but even using the "maximum" estimate of ultimate recovery, 70% have been recovered at end 200612. Note the UK figure includes fields which are not in the North Sea (onshore, West of Shetland).

Exact figures are debatable, because methods of estimating reserves vary and it is often difficult to forecast future discoveries.

Peaking in 1999, production of North Sea oil was nearly 6 million barrels (950,000 m³) per day. Natural gas production was nearly 10 trillion cubic feet (280,000,000,000 m³) in 2001 and continues to increase, although British gas production is in sharp decline 13.

UK oil production has seen two peaks, in the mid 1980s and late 1990s, with a decline to around 1.9 million barrels in the early 1990s.14 Monthly oil production peaked at 84.9 million barrels in January 198514 although the highest annual production was seen in 1999, with offshore oil production in that year of 2.559 million barrels per day15 and had declined to 1.452 million barrels in 2007.15 This was the largest decrease of any other oil exporting nation in the world, and has led to Britain becoming a net importer of crude for the first time in decades, as recognized by the energy policy of the United Kingdom.16 The production is expected to fall to one-third of its peak by 2020.citation needed

See also

Energy portal

External links

References

  1. ^ a b c d e f Glennie, KW (1998), Petroleum Geology of the North Sea: Basic Concepts and Recent Advances, Blackwell Publishing, pp. 11-12, ISBN 9780632038459 =, http://books.google.co.uk/books?id=BRoJwOzO3NUC&pg=PA11 
  2. ^ a b c "About NAM". NAM.
  3. ^ a b c Stauble, AJ; Milius, G (1970), "Geology of Groningen Gas Field, Netherlands", M 14: Geology of Giant Petroleum Fields (AAPG A009): 359-369 
  4. ^ a b c d e f g h (1982) The History of the British Petroleum Company. Cambridge University Press. ISBN 978-0521785150. 
  5. ^ "Key Dates in UK Offshore Oil & Gas Production". UK Offshore Operators Association.
  6. ^ "1975: North Sea oil begins to flow". BBC.
  7. ^ "High costs, high stakes on the North Sea". Time.
  8. ^ Rigzone Oilfield Database [1]
  9. ^ David Strahan, 2007 - The Last Oil Shock; Pages 61 & 62.
  10. ^ Jan Hagland,, Director of Information for the Norwegian Petroleum Directorate, Oil & Gas in the North Sea - ExploreNorth, http://explorenorth.com/library/weekly/aa091500a.htm, retrieved on 24 July 2007 
  11. ^ Norwegian "Facts 2007" official report, available freely here, [2], page 82
  12. ^ Estimate from DTI [3]
  13. ^ Official British production figures [4]
  14. ^ a b "UK Oil Production(m³)". BERR. (multiply figures by 6.290 to convert cubic metres to barrels)
  15. ^ a b "UK Annual Oil Production (m³)". BERR. (multiply figures by 6.290 to convert cubic metres to barrels)
  16. ^ The Independent
v • d • e
Flag of the United Kingdom United Kingdom topics
Primary subdivisions
History
Law
Politics
Geography
Economy
Military
Demographics
Culture
Portal
. - . - . - . - . Aforyzmy muzyczne odżywki kurs prawa jazdy warszawa hydrodeck Moony Scissor Sisters Santana Sandra RockwellGryzmoły | Artykuły | Artykuły | Teksty | Teksty | Ania z Zielonego wzgórza | Faraon | Syzyfowe prace streszczenie | Antyk | Pozytywizm | Kampania wrześniowa | Mendel Gdański - streszczenie | Norwid | Najlepsze szkoły językowe warszawa Tanio | Profesjonalne szkoły angielskiego warszawa Tanio i skutecznie