Petroleum and natural gas pools are abundant within the thick prisms of sediment deposited along many rifted continental margins. Where crustal collisions that assemble composite continents occur, the rifted-margin sediment prisms are drawn down against and beneath the suture belts thus formed. During such partial subduction, fluid hydrocarbons may be driven updip away from the subduction zones to accumulate in reservoirs along adjacent platform margins and within growing foreland fold-thrust belts. The immense petroleum accumulations of the Persian Gulf province southwest of the Zagros suture belt may owe their origin to this process. Similar oil migration in response to partial subduction may have influenced the distribution of petroleum in foreland basins generally; if so, strategies for exploration can perhaps be improved by taking this factor into account.