塔里木盆地油气输导体系及对油气成藏的控制作用

塔里木盆地纵向上含油气层系多,除二叠系外,自寒武系到新近系均获得了工业油气流;平面上,自盆地北部的库车地区至盆地南部,自塔东地区至塔西南地区,均有油气发现。油气平面分布的广泛性和垂向上的多层系与油气输导体系的类型及空间配置组合关系具有密切联系。研究表明,塔里木盆地发育了多种类型的油气输导体系,有不整合、断层、裂缝、渗透性输导层及火山刺穿等输导体。其中:断层输导体是油气垂向运移的高效通道,控制着塔里木盆地油气的纵向分布范围和规模;不整合输导体是油气长距离侧向运移的通道,控制了油气的平面分布范围;渗透性输导层既是油气长距离侧向运移的通道,也是重要的油气储集空间;而裂缝的最大作用则是增大渗透率,降低油气运移的阻力,并可显著改善储层的储集物性。总结了输导体系的类型及其对油气藏的控制作用,并探讨了输导体系有效性的主控因素,为塔里木盆地的油气勘探提供有益参考。

Types of hydrocarbon migration pathways and its controlling effects on hydrocarbon distribution in Tarim Basin

Tarim Basin is the largest hydrocarbon-bearing basin in the west part of China and has the most abundant hydrocarbon resources. The commercial oil and gas flows were found from the Tertiary to the Cambrian，except the Permian. Oil and gas reservoirs were also found on the plane from Kuche Depression in the north part to the Southwest Depression in the south part of Tarim Basin. Broad and vertical distribution of hydrocarbon is closely related to the extensive hydrocarbon migration pathways. Many kinds of hydrocarbon migration pathways such as unconformity, fault, fracture, permeable carrier bed and volcanic plug systems were developed in Tarim Basin. Among them, the fault is the efficient pathway for vertical migration of oil and gas and controls the vertical distribution of reservoirs, while the unconformity is the pathway for long-distance lateral migration of oil and gas and controls the transverse distribution of reservoirs. The permeable bed is the pathway for long-distance lateral migration and is also the important reservoir of oil and gas. The fractures have the important roles in improving the physical properties of reservoir rock, enhancing the permeability and reducing the resistance to oil-gas migration.The paper summaried the control factors for the validity of the hydrocarbon migration pathways and its controlling effects on hydrocarbon distribution,which would provide an important reference for the better understanding of hydrocarbon distribution in Tarim Basin.