FORMATION AND DISTRIBUTION OF THE PALEOZOIC MARINE CARBONATE-ROCK POOLS IN CHINA

The superimposing distribution of many sets of the Paleozoic marine source rocks and the further overlying of the Meso-Cenozoic continental strata resulted in the multi-source and multi-stage formation of the Paleozoic oil and gas pools in China.Hydrocarbon source rocks are distributed in craton basins and in-tracratonic rift basins.Carbonate rocks are major reservoirs, and argillaceous rocks are major local and regional caprocks.The hydrocarbon phases of the basins except for the Tarim Basin are dominated by dry gases including pyrolysis gases from kerogen and crude oil because of tectonic-thermal events.According to the characteristics of reservoirs, carbonate rock pools were divided into four types, that is, carbonate rocky-beach pools, uncomformity-karst pools, biohermal pools and diagenetic pools.Among them, carbonate rocky-karst pools and the beach-phase pools developed in high-energy environments are the most important types of oil and gas pools.Faults, unconformities and paleouplifts control the spatial distribution of oil and gas, and the distribution of oil and gas is diachronous.