Oleo e Gas Participacoes SA (OGX) is in danger of losing its 40% stake in a Brazilian offshore oil concession if it is unable to repay $31 million that it owes its two partners, Qgep Participacoes SA (BVMF:QGEP3) and Barra Energia, both of which hold a 30% stake in the concession, reports Jeff Fick for The Wall Street Journal. OGX owner Eike Batista has already lost at least $30 billion this year, and the oil company that was once his prize asset has struggled to meet production targets. The company filed for protection from creditors back in October, but it…