Measured in barrels of oil equivalents (boe), our international proved reserves consist of 79 % oil and 21 % natural gas, based on total international proved reserves of 1 039 mmboe.

Several of our international fields contribute positively to the reserves balance in 2009:

• Kizomba satellites phase 1 in Angola and the Caesar Tonga Unit in Gulf of Mexico, USA, were sanctioned in 2009.
• The Gimboa field in Angola commenced test production in April 2009.
• The PSVM development in Angola was approved by the concessionaire in 2008 and as a result recorded proved reserves for the first time in 2009.
• The Marcellus Shale Gas play in USA, part of our gas value chain strategy, recorded proved reserves in 2009 for the first time.
• The Leismer Demonstration Project in the Kai Kos Dehseh leases in Canada, with initial production scheduled for late 2010, contributes to the reserves balance in 2009 with reference to several analogous SAGD projects in operation in the Athabascan area.

Effective from 1 January 2010, the Russian state oil company Zarubezhneft became a partner in the Kharyaga PSA with a 20 % interest, thus reducing Statoil's share from 40 % to 30 % and having a negative effect on our reserves' balance.

The increase in the oil price during 2009 has had a negative effect on our proved reserves' estimates for international projects with a Production Sharing Agreement or a Buy Back Agreement.

The share of developed reserves at year end is 565 mmboe, up 5 % from 2008. Of the 2009 proved developed reserves, 413 mmboe are oil and 24.1 bcm (852 bcf) are natural gas. 

The following table shows our total international proved reserves as of 31 December for each of the last three years. Further information on reserves can be found in section 3.9 and in note 35 - Supplementary oil and gas information - to our Consolidated Financial Statements, which also explains revisions to the methodology for reserve estimation for 2009 compared with earlier years.