TEHRAN, Dec. 2 (Mehr News Agency) - National Iranian Oil Company (NIOC) ranked the second in the list of the world's 50 largest oil companies published by Petroleum Intelligence Weekly (PIW).

The PIW's ranking is based on operational data from over 130 firms. The focus on operations allows meaningful comparisons of all types of companies -- including state-owned firms -- and thus differs from more financially oriented corporate rankings.

PIW's system uses as criteria oil reserves and production, natural gas reserves and output, refinery capacity, and sales volumes.

Based on the report Saudi Arabia's Aramco continues its reign as number one, while Exxon Mobile of the U.S. stands third.

All three major Chinese energy firms made the Top 50, highlighting their aggressive push to secure oil and gas resources both at home and abroad.

CNPC jumped from the 7th place in the previous list to the 5th, ahead of British BP, Dutch Shell, and the U.S. ConocoPhillips.

Kazakhstan's Kazmunaigas and Uzbekistan's Uzbekneftegas appear in the Top 50 for the first time.

Below is the list of world's 10 top oil companies according to Petroleum Intelligence Weekly:

1. Saudi Aramco - Saudi Arabia
2. NIOC - Iran
3. Exxon Mobil - US
4. PDV - Venezuela
5. CNPC - China
6. BP - UK
7. Shell - UK/Netherlands
8. ConocoPhillips - US
9. Chevron - US
10. Total - France

The PIW''s report is recognized as the leading source of comparative assessments of oil companies' performance.

... Payvand News - 12/02/09 ... --