【摘要】 柴达木盆地北缘(柴北缘)地区发现了东坪气田和马北气田等富氦气田，其氦气成因和来源尽管有初步探讨，但氦气分布特征及富集机理的研究还比较薄弱。基于对柴北缘地区的系统采样及天然气样品组分和同位素测试，结合研究区的基底分布和构造特征等地质背景资料，总结了柴北缘地区富氦气藏的分布特征，深度剖析了富氦气藏与贫氦气藏的地质背景差异。研究结果表明：在柴北缘地区目前的在产气田中，东坪气田、尖北气田和马北气田的氦气平均含量大于0.1%,为富氦气田；牛东气田、昆特依气田和南八仙气田为贫氦气田。柴北缘地区富氦气田具有坐落在古老花岗岩基底之上、分布在深大断裂附近、气藏边底水活跃、经历了喜马拉雅期大幅度构造抬升和气藏的含气丰度较低等特征。构造抬升对柴北缘地区的氦气富集的控制作用表现在：(1)构造抬升作用形成的断裂系统为氦气的运移提供了高效通道；(2)构造抬升作用为深部含氦地质流体的向上运移提供了动力；(3)构造抬升作用为氦气沿古老储层横向运移并不断富集创造了条件。更多还原

【Abstract】 Helium-rich fields such as Dongping gas field and Mabei gas field have been found in the northern margin of Qaidam Basin. Although the origin and source of helium have been discussed, the studies on the distribution characteristics and enrichment mechanism of helium are still relatively weak. Based on the systematical sampling of natural gas in the study area for component testing, in combination with the geological backgrounds such as basement distribution and tectonic features, this paper summarizes the distribution characteristics of helium-rich gas reservoirs in the northern margin of Qaidam Basin, and deeply analyzes the differences in geological backgrounds between helium-rich and helium-poor reservoirs. The results show that among the gas fields in production in the northern margin of Qaidam Basin, Dongping, Jianbei and Mabei gas fields are rich in helium, with the average helium content greater than 0.1%, while Niudong, Kunteyi and Nanbaxian gas fields are helium-poor. In the study area, the helium-rich gas field is characterized by being situated on the top of an ancient granite basement, distributed near deep and large faults, boasting of active edge and bottom water, experiencing a large tectonic uplift during the Himalaya orogeny period, and having a low gas abundance in the gas reservoir. The controlling effects of tectonic uplift on helium enrichment in the northern margin of Qaidam Basin are as follows.(1)The fault system formed by tectonic uplifting provides an efficient channel for helium migration.(2)Tectonic uplift provides a driving force for the upward migration of deep helium-bearing geologic fluids.(3)Tectonic uplift creates the conditions for the transverse migration and continuous accumulation of helium along the old reservoirs.更多还原