TAIPEI ( TheStreet) -- China's CNOOC Ltd. (0883.HK), the massive state-run offshore driller, in May began looking for oil and natural gas under a tract of ocean south of its home base that is angrily disputed by five other governments.CNOOC and its share prices will pull through. The firm, whose acronym stands for China National Offshore Oil Corp., is on the prowl for proven undersea oil reserves estimated at 7.5 billion barrels. Its drilling site 320 kilometers southeast of Hong Kong effectively follows Beijing's unbending, sometimes belligerent claim to the South China Sea. The search for South China Sea deposits, apparently also a first for Beijing, faces possible competition from PetroVietnam (PVF:HoSE), which is run by the government in Hanoi and has started surveying. Vietnam claims the same 3.5 million-square-kilometer (1.4 million-square-mile) sea area, as does the Philippines. T Manila will give out 15 exploration contracts, including one to the British firm Forum Energy ( FET), the U.S. think tank Council on Foreign Relations says. But Malaysia is the most active of all claimants, owning half of a current total South China Sea production of 1.3 million barrels per day, according to research website GlobalSecurity.org.