波斯湾盆地烃源岩地球化学特征与油气分布规律

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

波斯湾盆地具有形成烃源岩优越的古构造、古地理、古气候等条件,长期继承性地发育多套海相优质烃源岩,即前寒武—寒武系海相碳酸盐岩、志留系热页岩、侏罗系海相碳酸盐岩、白垩系海相碳酸盐岩和古近系海相页岩。前寒武系至古近系烃源灶在波斯湾盆地从东南部至西北部发生迁移。波斯湾盆地油气存在"下气上油"的纵向分布特征和"东南气西北油"的平面分布特征。烃源灶分布及规模控制油气分布范围及资源规模。烃源岩成熟度控制着纵向和平面油气相态分布。

Various types of hydrocarbon source rocks are developed in the Persian Gulf Basin, inclu- ding the Precambrian-Cambrian marine source rock, the Silurian hot shale, the Jurassic marine car- bonate 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 circula- tions 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 oc currence and size of the hydrocarbon kitchens, and the vertical and lateral changes in oil/gas phases controlled by the thermal maturety of source rocks.