准噶尔盆地乌夏断裂带输导体系对油气运聚的控制

主要由断裂、不整合和连通砂体等3种类型组成的输导体系,在乌夏断裂带油气运聚成藏过程中起到了至关重要的作用。乌夏断裂带深部断裂系统活动期和油气运聚期相匹配,深部断裂系统是油气从烃源岩向上发生大规模垂向运移的重要通道。乌夏断裂带不整合结构中的底砾岩和半风化岩石孔渗性较好,是油气横向运移的主要通道和油气聚集场所。乌夏断裂带连通砂体有良好的孔渗性能,是油气横向运移的良好通道。乌夏断裂带油气经过＂断裂-不整合-砂体＂复合输导体系的运移,形成多种与输导体系有关的油气藏,并发育了4种成藏模式：近源侧向砂体-不整合输导早期成藏模式、近源垂向断层输导多期成藏模式、远源混向＂Z＂字型输导多期成藏模式和远源混向阶梯状输导晚期成藏模式。

Control of pathway systems on hydrocarbon migration and accumulation in Wuerhe-Xiazijie fault belt, Junggar Basin

Pathway systems,which play an important role in the hydrocarbon migration and accumulation in Wuerhe-Xiazijie fault belt,mainly consist of faults,unconformities and connected sand bodies.In terms of the frequency and velocity of the faults movements,the periods of deep fault system movements coincide with the periods of hydrocarbon migrations and the deep fault systems are the main migration pathways for hydrocarbon vertical migrations.In the unconformities of Wuerhe-Xiazijie fault belt,the basal conglomerates and semi-weathered rocks having good porosity and permeability are favorable horizontal migration pathways.The sand bodies having preferable connection,pore structure and thickness are good horizontal migration pathways as well.In Wuerhe-Xiazijie fault belt,the hydrocarbons migrate through the composite pathway systems such as fault-unconformity-sand body and form many reservoirs related to the pathway systems.According to the sources of oil and gas,migration pathways and directions,and the reservoir-forming periods,four types of accumulation modes develop： near source-lateral sand body and unconformity migration-early accumulation modes;near source-vertical fault migration-multiple phase accumulation modes;long distance migration-multiple migration pathways-multiple phase accumulation modes;long distance step migration-multiple migration pathways-late accumulation modes.