July 28 (Reuters) - The cost of pumping a barrel of oil out of the ground depends on a variety of factors, including the size and accesibility of the field.
Oil companies are often reluctant to give precise cost information.
The following provides estimates of the cost of running a field for OPEC members and other individual countries, obtained from traders and industry analysts.
It also gives the International Energy Agency's more general assessment of costs for the oil-producing regions of the world.
ESTIMATES BY COUNTRY
Saudi Arabian crude is the cheapest in the world to extract because of its location near the surface of the desert and the size of the fields, which allow economies of scale.
The operating cost (stripping out capital expenditure) of extracting a barrel in Saudi Arabia has been estimated to be around $1-$2, and the total cost (including capital expenditure) $4-$6 a barrel.
Extraction of Iraqi oil is in theory also very cheap, although there are political and security challenges.
Industry analysts estimated total costs at between $4-6, although they said some fields could be more expensive.
In the United Arab Emirates, operating and capital costs combined were estimated to be around $7 a barrel.
Oil extraction from mature and deep water offshore fields is much more expensive than from the accessible hydrocarbon territory of the Gulf.
In Nigeria, production in ultra-deep water fields can reach $30 a barrel compared with onshore costs of around $15, according to analysts.
In offshore Angola, it costs around $40 to produce one barrel of oil (operating and capital costs), traders told Reuters.
Operating and capital costs in Algeria, Iran, Libya, Oman and Qatar were all estimated to be around $10-15 a barrel.
In Kazakhstan, where reserves are big and largely unexploited, the cost to produce a barrel for medium-sized producers, such as Kazakh state oil company KazMunaiGas [KMG.UL] is around $15-18, and for Kazakhstan's largest operator Tengizchevroil, it is about $10-12, the Kazakh-British Chamber of Commerce said.
Analysts said these were operating costs, probably including transport, as it is expensive to move the oil to distant ports.
In Venezuela, where fields tend to be mature and small and it is difficult to make new discoveries, production costs were generally estimated at $20 a barrel (operating and capital costs).
Those figures do not include the more expensive Orinoco oil from the country's sand deposits.
One analyst said the extraction of one barrel of Orinoco was around $30 (operating and capital costs).
Ecuador, where fields are also small and the distance to ports add to costs, analysts pegged extraction costs at $20 a barrel.
In the mature British North Sea, where the remaining oil is difficult to access, the industry body Oil & Gas UK said the break-even cost was around $50 a barrel. One analyst said operating and capital costs were $30-40 a barrel.
The International Energy Agency (IEA) -- in its latest November 2008 world energy outlook -- gave the following estimates for the all-in costs of producing oil from various types of hydrocarbons in different parts of the world:
Oilfields Estimated Production /source Costs ($ 2008) Mideast/N.Africa oilfields 6 - 28 Other conventional oilfields 6 - 39 CO2 enhanced oil recovery 30 - 80 Deep/ultra-deep-water oilfields 32 - 65 Enhanced oil recovery 32 - 82 Arctic oilfields 32 - 100 Heavy oil/bitumen 32 - 68 Oil shales 52 - 113 Gas to liquids 38 - 113 Coal to liquids 60 - 113 Source: International Energy Agency World Energy Outlook 2008 (Compiled by Martina Fuchs, Christopher Johnson, Karen Norton, Joe Brock and Barbara Lewis, Editing by James Jukwey)