MOECO wins in the 2006 bidding round for Indonesian exploration block

March 7, 2007 Project

Mitsui Oil Exploration Co., Ltd. ("MOECO", Head office: Hibiya Central Bldg. 2-9, Nishi Shimbashi 1-Chome, Minato-ku, Tokyo, JAPAN / President: Mr. Yoshiyuki Kagawa) is pleased to announce that it has been selected as the winning bidder for Tuna Block located in eastern part of Indonesia's Natuna Sea as part of a joint bid lodged with Premier Oil on 2006 Bidding Round on 2nd March.

Premier will be the operator of the Area and hold a 65% working interest with the remaining 35% interest of MOECO. Premier and MOECO are planning to sign the Production Sharing Contract with the MIGAS by the end of March 2007.

MOECO is currently active in Thailand, Cambodia, Vietnam, Middle East, the United States, Libya and Indonesia.

MOECO's acquisition of an interest in the Tuna PSC is further step for MOECO in realizing its strategy of expansion of its business activities in Indonesia. An exploration success in the block would contribute to and complement its business activities and strengthen its business structure and production base. MOECO is also pleased to be able to make a contribution to the economic growth of Indonesia through its investment and increased job opportunities for the Indonesian people.