Comparison among Petroleum Distribution Patterns of Three Richest Foreland Basins in Petroleum Resources in the World

The Persian Gulf Basin,Eastern Venezuela Basin and Western Canada Basin are the richest petroliferous foreland basins in the world.Analyses of the up-to-date oil and gas geological data indicate that there are significant differences in oil and gas distribution features and hydrocarbon resource mixes among the three foreland basins.Within the foreland basins,oil and gas are widely distributed throughout both the thrust-fold belt and foredeep-slope,but the discovered reserves are mainly concentrated in the foredeep-slope.Stratigraphically,passive margin tectono-strata host over 91.0% of the discovered reserves in the Persian Gulf Basin while foreland sequences are the major reservoir intervals in the Eastern Venezuela Basin and the Western Canada Basin.The petroleum resources of the Persian Gulf Basin are dominated by conventional oil and gas while the Eastern Venezuela Basin and the Western Canada Basin are endowed with unconventional heavy oil and natural bitumen.The spatial configuration relationship between regional seals and petroleum migration pathways controls the different mixes of hydrocarbon resources in the foreland basins.