Russia's Sakhalin-1 project, which is led by Exxon Mobil, recorded a 14% fall in oil production last year due to the natural process of field depletion.
The project is operated by Exxon's Russian affiliate Exxon Neftegas Limited (ENL) together with Rosneft, India's Oil and Natural Gas Corporation (ONGC) and Japan's Itochu and Marubeni.
Sakhalin-1's crude extraction declined to 8.2 million tonnes in 2009 compared with 9.6 million tonnes in 2008, according to Reuters.
The project, which achieved 11.2 million tonnes peak production in 2007, has been generating oil for the last few years.
ENL said the project has completed the first two extended-reach wells out of the seven wells that will exploit the reservoir at the Odoptu field.
The Yastreb rig was used to drill a target area in the Odoptu oil reservoir, which was 9km offshore.
The Odoptu field is expected to commence oil production in the second half of 2010.
The project involves phased development of the Odoptu, Arkutun-Dagi and Chayvo fields, which contain 2.3 billion barrels of oil resource and 17 trillion cubic feet of natural gas.
ENL holds 30% stake in the project followed by Sakhalin Oil and Gas Development with a 30% stake, RN-Astra with 8.5%, Sakhalinmorneftegaz-Shelf with 11.5% and ONGC Videsh with 20%.