关键词: 柴达木盆地, 北部块断带, 断层系统, 油气成藏, 油气运移, 控制因素

Abstract: The faults controlled oil and gas accumulation in the North Block-faulted Belt of Qaidam Basin.In the section,the North Block-faulted Belt developed three sets of fault systems including lower thrust fault system,upper detachment fault system and top normal fault system.The lower thrust fault system controlled the distribution of source rocks and the formation of primary reservoirs.The upper detachment fault system controlled the formation of mid-shallow traps and secondary reservoirs.The top normal fault system could destroy oil and gas reservoirs.The qualitative analysis and quantitative estimation showed that in the static period of fault,the lateral seal-ability of fault got better from deep to shallow in depth,and the vertical seal-ability of fault got better from west to east.In the active period,the faults became the key vertical channels for hydrocarbon migration in the researched area.The vertical migration channels in the North Block-faulted Belt constituted three migration models including the upper and lower fault connective model,unitary model and disjunctive model.The hydrocarbon migration ability of the connective and unitary models was better than that of the disjunctive model,which resulted in the difference of hydrocarbon accumulation in the North Block-faulted Belt.

Key words: Qaidam Basin, North Block faulted Belt, fault system, oil gas accumulation, oil and gas migration, control factors