摘要
Non-hydrocarbon gases,such as CO2(carbon dioxide) and N2 (nitrogen), have been discovered in the marginal basin of northern South China Sea. The formation and accumulation of these gases require some specific geological conditions and controlling factors. The CO2 of Crustal type and crust-mantle mixed type and the N2 of crustal organic type and crustal organic-inorganic hybrid type are mainly enriched in the shallow part of the central diapir area of the Yinggehai basin along the northwest strike-slip extensional edge of the northern South China Sea. The degasification of the volcanic mantle provided the gas sources and the deep faults were the path for gas migration to traps.