Addax Petroleum Corp., Geneva, Switzerland, (Toronto: TSX) plans to buy working interest in the Gulf of Guinea from Esso Exploration and Production Nigeria-Sao Tome "One" Ltd., a subsidiary of ExxonMobil Corp., Irving, Texas, (NYSE: XOM) for US$77.6 million. Addax acquired a 40% working interest in Block 1 of the joint-development zone (JDZ) in deepwater between Nigeria and Sao Tome and Principe. Block 1 is operated by Chevron Corp., San Ramon, Calif., (NYSE: CVX) which holds a 45.9% working interest on 69,600 acres.