Royal Dutch  Shell, France’s Total and Eni sold a 45 percent stake in a Nigerian oil bloc to a Polish-Nigerian consortium Kulczyk Oil, a partner in the consortium, said late on Friday.

The price paid by the consortium consisting of Kulczyk Oil and Nigeria’s Nest Oil, Aries and VP Global was not disclosed, but a source told Reuters the deal was worth $600 million.

Kulczyk Oil said in a statement it has acquired 9 percent of the OML 42 block, a stake which could produce 11.5 million to 46.4 million barrels of oil equivalent.

“Kulczyk Oil believes these estimates are cautious because they do not take into account significant volumes of gas,” the statement said.

The transaction is subject to a number of approvals, including permission from National Petroleum Corporation, NNPC, which owns the remaining 55 percent of the bloc.