SAO PAULO (Reuters) – Swedish oil firm Maha Energy said on Wednesday it acquired 5% of Brazil’s 3R Petroleum and proposed to its board a carve-out of 3R’s onshore oil assets, which would then be combined with a third company. In an open letter to 3R’s board, Maha said Brazilian oil firm PetroReconcavo is the “natural candidate” for the deal, given the extensive existing synergies between its assets. Under the proposal, 3R’s onshore oil concessions, midstream and downstream assets would be combined with PetroReconcavo. The firm would remain in control of its offshore assets and its shareholders…