The system , which gives the state at least a 60 percent stake in projects where foreign oil companies were once paid production fees , was signed on Monday by 16 companies that include Petrobras of Brazil , Chevron and Royal Dutch Shell .
Petrobras /business/company/major_shareholders Brazil
Brazil /business/company_shareholder/major_shareholder_of Petrobras
DT NN , WDT VBZ DT NN IN JJS DT CD NN NN IN NNS WRB JJ NN NNS VBD RB VBN NN NNS , VBD VBN IN NNP IN CD NNS WDT VBP NNP IN NNP , NNP CC NNP NNP NNP .