FACTBOX - Details of the final Kashagan agreement

ASTANA (Reuters) - Kazakhstan and a consortium of Western oil companies developing the Kashagan oilfield signed the final agreement on the future of the project on Friday after more than a year of tense negotiations.

Below are key facts about Kashagan and the final amended final Production Sharing Agreement (PSA):

* Kashagan is considered the world's biggest oil find since the discovery of Prudhoe Bay in Alaska in the 1960s.

* It holds an estimated 38 billion barrels of oil-in-place of which 13 billion are potentially recoverable with the use of gas re-injection. Kazakhstan plans to triple its oil output in 15 years with the field, becoming a key source of non-OPEC oil for the European Union.

* The Eni-led AgipKCO consortium developing the field also includes Royal Dutch Shell, Exxon Mobil, Total, ConocoPhillips, Japan's Inpex Holdings Inc and the Kazakh oil company .

* The October 31 deal puts the stakes owned by Eni, Exxon Mobil, KazMunaiGas, Royal Dutch Shell and Total at 16.81 percent each. ConocoPhillips gets 8.40 percent and Inpex 7.56 percent.

* Kazakh officials gave no details of the final agreed budget at the time of the agreement's signing on October 31. The government earlier said the final budget was fixed at $136 billion (84.3 billion pounds), up from the previous estimate of $57 billion. The consortium has invested $12.3 billion so far.

* Commercial production at the field, originally scheduled for 2005, has been delayed several times due to technical difficulties. The October 31 deal puts the start date at late 2012.

* The first phase, which will take two to three years, will see output rising from the initial 75,000 barrels per day (bpd) to 300,000 bpd. At the beginning of the second phase, additional injection facilities will boost it to 450,000 bpd.