Global oil company Royal Dutch Shell unveiled plans on Wednesday to sell its stake in four Brazilian offshore blocks, including a field in the vast deepwater subsalt region. The company said it would sell its stakes in the BS-4, BM-S-8, BM-S-45 and BM-ES-28 blocks. The projects also include investment by Brazil’s state oil company Petrobras, U.S.-based Chevron, Portugal’s Galp and Brazilian miner Vale.