中国氦气资源分区特征与成藏模式

Zoning characteristics of helium resources and helium accumulation model in China

氦是目前已知的熔点、沸点最低的惰性气体元素,物理性质极为特殊,被广泛应用在诸多高精尖领域。中国的氦气资源主要依赖进口,但是近些年随着国内氦气需求量的持续增加、氦气进口价格的升高以及国外主要氦气生产国出口政策的收紧,中国面临严峻的氦气资源安全形势,急需对国内氦气资源的分布特征、成藏模式和控制因素开展深入研究。为此系统调研了中国10个含油气盆地的含氦情况,对氦气分布的地区特征、地层时代特征以及氦气成藏模式进行了总结,中国富氦盆地横向分布广泛且具有明显的分区特征,东部与中西部含氦盆地差异显著,东部含氦盆地有壳源氦和壳幔混合型氦并以后者为主,主要受构造因素和幔源流体的控制;中西部含氦盆地以壳源氦为主。纵向上氦气在各地层时代中均有分布,氦气含量具有“两头高、中间低”的特征。明确了氦源岩、构造因素、运移载体和封盖条件在氦气成藏中的控制作用,并据此总结出中国东部含氦盆地和中西部含氦盆地的氦气成藏模式,根据氦气成藏中存在的2组相互制约关系:气藏生成强弱的相互制约、构造活动性强弱的相互制约,指出“通量差”是氦气成藏的关键参数。对中国氦气资源勘探开发提出如下建议:围绕东部壳幔混合型氦气资源开展资源量评估工作,对中西部含氦气田应当加快氦气分离、提氦装备的建设,推进氦气资源的工业开发,同时,进一步提高对非常规气藏中氦气储量评估工作的重视程度。

Helium is the inert gas with the lowest known melting and boiling points.It has extremely special physical properties and is widely used in many high-precision fields.However,with the increasing demand for helium in China,the rising price of imported helium,and the tightening of export policies of major foreign helium-producing countries,China is facing a serious situation of helium resource security.The helium-rich basins in China are widely distributed horizontally and have obvious zoning characteristics,with significant differences between the eastern and central-western helium-bearing basins.The eastern helium-bearing basins have crustal helium and mixed crust-mantle helium with the latter predominating,and is mainly controlled by tectonic factors and mantle-derived fluids,while the central and western helium-bearing basins are dominated by crustal helium.The helium is distributed in all stratigraphic ages vertically,and the helium content has the characteristics of“high at both ends and low in the middle”.The role of helium source rocks,tectonic factors,transport carriers,and capping conditions in helium reservoir formation is clearly identified,and the helium reservoir formation patterns in the eastern and central-western helium-bearing basins in China have been summarized accordingly.According to two groups of mutual constraints in helium accumulation:the mutual constraints of gas reservoir generation and tectonic activity,it is pointed out that“flux difference”is the key parameter for helium accumulation.The following suggestions are made for the exploration and development of helium resources in China:Resource assessment work should be carried out around the eastern basins with the mixing of crustal and mantle resources,the construction of helium separation and extraction equipment should be accelerated for the central and western helium-bearing fields to promote the industrial development of helium resources,and the importance of helium resource assessment work in unconventional gas reservoirs should be increased.