Two major oil-producing regions frame this article. The first is the onshore oil world in the global South (the Niger delta in Nigeria as part of the wider Gulf of Guinea), and the second is the offshore world of deepwater oil and gas exploration and production in the United States (specifically, the Gulf of Mexico, and the Deepwater Horizon blowout). Both arenas can be seen as oil frontiers—frontiers of accumulation and dispossession—rooted in the operations of specific oil assemblages. I trace the relations between the deep infrastructures of the oil world—pipelines, rigs, flowstations, tankers, financiers, engineering firms, security forces, and so on—and to the regimes of life and death in the postcolonial South and the advanced capitalist North. Political, economic, and social relations are, as Timothy Mitchell notes, engineered out of the flows of energy. Opening up these sorts of oil frontiers—whether in Angolan or Brazilian deepwater, Russian Siberia, or increasingly now the frozen frontiers of the Arctic—necessitates engagements with place-specific social and political forces, none of which necessarily or easily are compatible with some presumed set of desires of corporate oil capital—political stability, surplus management, price control—or indeed of imperialist oil-consuming states. In one case the terminal point is an insurgency and combustible politics threatening the very operations of the oil industry and the petrostate itself; in the other it is the violence of a blowout—the loss of human and environmental life and livelihoods—and of the deadly consequences of substituting technical and financial over political risks.