SOURCE ROCK GEOCHEMISTRY AND ITS BEARING ON PETROLEUM OCCURRENCE IN THE PERSIAN GULF BASIN

Various types of hydrocarbon source rocks are developed in the Persian Gulf Basin, including the Precambrian-Cambrian marine source rock, the Silurian hot shale, the Jurassic marine carbonate source rock, the Cretaceous marine carbonate source rock and the Paleogene marine source rock. The formation of organic-rich marine source rock in the Persian Gulf Basin depends upon such elements as paleotectonics, paleogeography, paleoclimate, paleogeomorphology, paleoceanic circulations and paleoenvironment. The hydrocarbon kitchens from the Precambrian to Paleogene shifted with time from the southeast to the northwest in the Basin. They are distributed in a vertical pattern from gas in the lower strata and oil in the upper strata and a lateral pattern from gas in the southeast and oil in the northwest. The distribution and resource potential of petroleum are controlled by the occurrence and size of the hydrocarbon kitchens, and the vertical and lateral changes in oil/gas phases controlled by the thermal maturety of source rocks.