BP PLC has obtained approval from the Ministry of Commerce to explore in the South China Sea in what will be the company's second deepwater project in China.

BP last week received a green light to have a presence in a gas field known as block 43/11, Chen Liming, president of BP China, said on Tuesday. The China National Offshore Oil Corp operates the field.

Chen said BP will have a roughly 40 percent stake in the block during the exploration period and a 20 percent share when the project has moved into production.

The ministry's approval was the final official step needed before the project can begin. Chen did not say when the exploration will start.

BP and CNOOC signed a cooperation agreement for the project during Vice-Premier Li Keqiang's visit to London in January.

BP's participation in block 43/11 will diminish the size of a share held in the project by Anadarko Petroleum Corp, a US energy company, which previously had a 50 percent stake in the block under a contract with CNOOC. The planned exploration will mark BP's second deepwater project in China. In September 2010, it bought a 41 percent stake in another block in the South China Sea.

With CNOOC, China has shown its ambition to tap into deepwater resources. The country plans to use its first semi-submarine drilling rig, Hai Yang Shi You 981, for deepwater exploration in the South China Sea as early as the first half of this year.

The rig is capable of working at depths of 3,000 meters and extracting oil from sources that are as deep as 12,000 meters.

Chen at BP said such deepwater work is among the four areas of opportunity the company wants to exploit in conjunction with its Chinese counterparts in China and overseas markets. The other three pertain to natural gas - both conventional and unconventional types - integrated refining and chemicals and high-end lubricants.

BP also said it plans to spend about $630 million on the third phase of a project to make purified terephthalic acid - which are used in many plastics - at its BP Zhuhai Chemical Company Ltd plant in Guangdong.

The third phase will make the plant capable of churning out 1.25 million tons of the chemical a year. It is expected to begin operating as early as 2014 but is still subject to approval from the Ministry of Commerce, the company said.

From its entrance into China in the late 1970s to the end of 2010, the oil company has invested about $5 billion into the country.