摘要:
七、八十年代地学研究的热点和前沿领域之一是关于地幔的研究,氦是地幔挥发分的重要组成。其同位素3He/4He的丰度比是判识含氦地质体来源于幔、壳和大气的重要指标,其相应的表征值为1.1×10-5,10-6和1.4×10-6,在研究我国东部含油气区的工业气井天然气组分和同位素组成时,发现一批沿郯庐大断裂两侧分布的工业气井,其氦浓度为0.05～0.1％,达到了氦气资源所要求的品位.其3He/4He比值达3.7×10-6～6.36×104,由于工业气井中大气氦的组分可忽略不计,可用壳-幔二元混合模式计算氦气中幔源氦所占份额,结果表明幔源氦达33.7～57.3％,从而在我国领土上第一次发现了幔源氦在沉积壳层形成工业储集。为了解这一发现在国际上的意义位置,请中科院兰州文献情报中心科技文献检索室进行了国际联机检索,证明从1967年到1991年3月（从可能出现有关文献及1990年我所论文发表分别作了相应时间的前后延伸）国际上无有关报导,证明这一发现在世界范围也是首次。此项发现对我们更深入认识地球、地幔形成演化,对于进一步了解幔源挥发份的脱气、运移乃至成藏有重大理论意义,从而对指导有关矿产的勘查也具有实践意义。
Abstract:
There are three kinds of helium in the earth,i. e. atmospheric,crust derived and mantle derived ones, which's He/4He ratio are 1. 4 × 10-4,2 × 10-10,1. 1 × 10-5 respectively. Mainly resourced from natural gas reservoirs,helium concentration if mainly related to the α decay of urinium and thorium, thus,its enrichment generally is accompaning by the decrease of He/4He ratio, ordimarily in the grade of 10-8. Based on the recent years of the both side of Tancheng - Lushan Fault in eastern China,the author found the helium abundance reached or higher than 0. 1% in some industrial gas droll holes,i.e.,up to the standard of industrial helieum reservoir,but the intresting point is that the He/4He ratio measured is as high as 3.7-6.36×10-6. As atmospheric He can be neglected in industrial wells, and the calculation shows that the mantle derived He can up to 33.7-57. 3% of these He gases,then the industrial He reservoirs in the sedimentary crust that derived from the mantle were first found internationally. It is a discover of a new helium source, moreover, it not only provided information of the analysis, migration, reservoir of mantle volatile components, but also a geological body to study on the hot point of geoseience.i. e, the relationship between the crust and the mantle. And the discovery of industrial helium reservoir is also significant of the research of non - biogenic methane and so on.
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