Abstract: The plutonic fault-42,shallow fault-Ⅰin culmination-2 in Lenghu-5 structure,plutonic Xiannan fault and shallow Xianbei fault in Nanbaxian structure play a principal role in gas pool forming in north edge of Qaidam Basin.According to geological analysis and mathematical estimation,the fault sealability in those two structures shows obvious diversity:the lateral sealability of plutonic fault is better than that of the shallow one in Lenghu-5 structure;the lateral sealability of shallow fault is better than that of the plutonic one in Nanbaxian structure.The vertical sealability in Lenghu-5 structure is stronger sealability than that in Nanbaxian structure in corresponding depth in different structure synthem.The vertical sealability of Xiannan fault in Nanbaxian structure is relative inferior,which stretch as channel-way of oil-gas from maturation period of oil-gas to peak-period of hydrocarbon generation.Xianbei fault is patulous lower and obturation upper which is adventageous to gas pool formation.

Key words: Qaidam Basin, fault, sealability, natural gas, paint factor

摘要： 柴达木盆地北缘冷湖五号二高点构造深部42号、浅部Ⅰ号断层和南八仙构造深部仙南、浅部仙北断层对成藏起主要控制作用,通过地质分析和数理评价发现,这两个构造断层的封闭性具有明显的差异:冷湖五号构造深部断层比浅部断层侧向封闭性好,南八仙构造浅部断层比深部断层侧向封闭好;不同构造深浅部对应的断层中,冷湖五号构造比南八仙构造的断层具更强的垂向封闭.南八仙构造仙南断层垂向封闭性较小,开启期发生于油气成熟到生烃高峰期,起通道作用,仙北断层具下开上闭性,有利成藏.

关键词: 柴达木盆地, 断层, 封闭, 天然气, 涂抹系数