Formation And Distribution Of Giant Oil And Gas Fields In Persian Gulf Basin

Persian Gulf basin has the largest oil and gas fields in the world, and oil and gas resources are rich in the Persian Gulf basin. The research on Giant oil and gas Fields in Persian Gulf Basin will enrich petroleum geology theory, and can also provide the reference basis for our country’s overseas oil and gas exploration. In this area there is not only the superior oil aggregation condition, but also the favourable gas accumulation geological conditions. What geological conditions decide this? In our country and others, Experts and scholars are all very interested in this question. In this paper,based on the data of discovered one hundred and fifty five giant oil fields and fifty four giant gas fields in the Persian Gulf basin, application of petroleum system concept and analysis method,dissecting one by one giant oil and gas field, we probe into the formation and distribution of giant oil and gas fields in Persian gulf basin.The study shows that the source rocks of giant oil and gas fields are Precambrian source rock, Paleozoic source rock, Mesozoic Jurassic and Cretaceous source rock and Cenozoic source rock. In South of Oman,oil and gas are rich in Paleozoic clastic rock reservoir. In North of Oman,oil and gas are rich in Mesozoic reservoir. In central of Arabia basin,oil and gas are rich in Mesozoic reservoir. In Zagros basin, oil and gas are rich in Cenozoic reservoir. Giant oil and gas fields are controlled by the Lower Triassic Sudair Formation tight limestone regional cap rocks, Upper Jurassic Tithonian Hith Formation anhydrite seal, Middle Cretaceous Cenomanian shale, Upper Cretaceous thin bed limestone, Lower and Middle Fars Formation (Gachasaran Formation) evaporite rock seal. The main trap is structrul trap.Analysis obtained that giant oil fields are mainly discovered during the time from 1950 to 1990. Giant gas fields are mainly discovered during the time from 1960 to 1980. Giant oil fields are concentrated in Widyan Mesopotamia basin in Saudi Arabia. Giant gas fields are concentrated in Zagros basin in Iran. In Zagros basin, oil and gas are rich in Permian, Triassic, Cretaceous and Tertiary layer. In Central Arabian basin, oil and gas are rich in Permian, Triassic, Paleozoic, Jurassic and Cretaceous layer. In Rub Al Khali basin, oil and gas are mainly rich inJurassic layer, and are also rich in Permian and Cretaceous layer. In Oman basin, oil and gas are rich in Cambrian, Ordovician and Cretaceous layer. In Widyan Mesopotamia basin, oil and gas are rich in Cretaceous layer. Persian Gulf basin giant oil and gas fields are rich in Mesozoic reservoir. Main lithology of Giant oil and gas fields is carbonate rock. The main depth of Giant oil and gas fields is within 3 kilometres. Tectonic setting, the distribution of source rock, the valid combination of reservoir and seal, basement uplift zone and transform zone, salt bed and late tectonic compression are controlled the distribution region of oil and gas and the accumulation layer of oil and gas. The potential of gas exploration in Persian Gulf basin is huge. Predicting favorable exploration areas are: The first areas are "areas which have been explored and developed", and these areas’exploration targets are tectonic trap exploration targets.The second areas are "areas which have been explored and developed", and these areas’exploration targets are non-tectonic trap exploration targets. The third areas are "areas which have not been explored and developed".