An in-house legal team at China Petroleum & Chemical Corp., also known as Sinpec, negotiated a $1.1 billion deal that will see the Chinese state-owned enterprise acquire five oil and gas fields in Kazakhstan from Russian oil producer Lukoil Public Joint Stock Co.

Sinopec is buying the remaining 50 percent in Caspian Investments Resources Ltd., a joint-venture with Lukoil since 2010, that it doesn't currently own. The Chinese energy company will now have full control over the fields in western Kazakhstan, which has 219 million barrels of proved oil and gas reserves and mainly supplies the European market.

Sinopec paid an undisclosed sum in 2010 for its share of Caspian Investments from Indian conglomerate Mittal Group, which bought its 50 percent stake from Lukoil for $980 million in 2007.