BG Group leads a consortium of energy companies in reaching a multibillion-dollar deal with Kazak officials to explore the Karachaganak field in northwestern Kazakhstan.
The deal includes share swaps and cash considerations between members of the consortium and state-run KazMunaiGas, which acquires a 10 percent stake in the project.
BG Group Executive Vice President Ashley Almanza said the field holds significant deposits of oil and natural gas but only 10 percent of it has been produced.
"Today's agreement ensures strong alignment with the Republic of Kazakhstan and provides the foundation for realizing the vast remaining potential and value in Karachaganak," she said in a statement.
Foreign energy majors took over Karachaganak in the 1990s. It holds roughly 2.4 billion barrels of oil and an estimated 15 trillion cubic feet of natural gas.
Talks over the government acquisition of shares in Karachaganak were complicated by a tax row between Astana and the members of the foreign consortium.
The venture consists of BG Group, Italian energy company Eni, U.S. supermajor Chevron and Russia's Lukoil.