Evolution of lithofacies and paleogeography and hydrocarbon distribution worldwide (II)

Abstract

Based on the compilation and analysis of the lithofacies and paleogeography distribution maps at present and paleoplate locations during six key geological periods of the Mesozoic and Cenozoic, the lithofacies and paleogeography features and their development laws were expounded. Based on our previous research results on lithofacies and paleogeography from Precambrian to Paleozoic, we systematically studied the features and evolution laws of global lithofacies and paleogeography from the Precambrian and their effects on the formation of source rocks, reservoirs, cap rocks and the distribution of oil and gas worldwide. The results show that since Precambrian, the distribution areas of uplift erosion and terrestrial clastic deposition tended to increase gradually, and increased significantly during the period of continental growth. The scale of coastal and shallow marine facies area had three distinct cycles, namely, from Precambrian to Devonian, from Carboniferous to Triassic, and from Jurassic to Neogene. Correspondingly, the development of shallow carbonate platform also showed three cycles; the lacustrine facies onshore was relatively developed in Mesozoic and Cenozoic; the sabkha was mainly developed in the Devonian, Permian and Triassic. The Cretaceous is the most important source rock layers in the world, followed by the Jurassic and Paleogene source rocks; the clastic reservoirs have more oil and gas than the carbonate reservoirs; the basins with shale caprocks have the widest distribution, the most abundant reserves of oil and gas, and the evaporite caprocks have the strongest sealing capacity, which can seal some huge oil and gas fields.