Abstract:

Of all the oil and gas shows in the marine strata in Central Yangtze Region,bitumen is most common,then oil shows,and the gas shows are the last.Since hydrocarbon evo-lution degrees are different,bitumen is mostly in Lower Paleozoic,gas shows mainly in the Silurian and Devonian,and oil slows in the Permian and Triassic.This indicates that gas exploring should aim at the Paleozoic and oil at Mesozoic.The oil and gas shows are concentrated in the two limbs of Huangling anticline,the north margin of South Jiangnan Uplift and the two limbs of Chenhu-Tuditang syncline.It is obvious that the loss of oil and gas are bound up with strong uplift and denudation.Tensile and tensile-shear faults are the principal factor in controlling oil and gas shows,and the migration path and accu-mulation space as well as the chief factor of hydrocarbon lossing.Most of the oil and gas showings are in fracture,fracture-miarolitic cavity and fracture cave.The study of oil-gas shows indicates that,Lixian Sag is one of the best areas in hydrocarbon potential in the Central Yangtze Region.The fault draps covering the footwall of the faults are favourable storages.The limbs of Chenhu-Tuditang syncline are the localities for the migration,accumulation and escape of hydrocarbon,and the place of the unity of oppo-sites is important for seeking oil and gas.