摘要
本文研究了天然气中氮的地球化学特征，并讨论了氮的成因。中国含油气盆地内绝大多数天然气的含氮量小于６％，测得天然气的δ１５Ｎ值分布在－５７‰和＋９５‰之间．多数在－２０‰＋２０‰的范围内。沉积盆地内天然气中的氮以分子形式被吸附于岩石的碎屑表面或以游离状态分布于岩石孔隙中。富氮天然气主要分布于深大断裂带或新生代岩浆活动地区。天然气的氮既有有机成因的，也有无机成因的。
The geochemical characteristics and origins of molecular nitrogen in natural gases are discussed on the basis of geology and geochemistry. Most of natural gases from Chinese oil and gas fields contain less than 6 percent of molecular nitrogen. The isotope composition of nitrogen in natural gases has a range of - 57‰ to 95‰, most of δ15N values scatter between 20‰ and +20‰. Natural nitrogen gas in the sedimentary basins adheres to the surface of fragments in rocks as molecule or occurs in pores of rocks as free gas. Natural gases enriched nitrogen are mainly found in the deep-fracture zones or Cenozoic volcanic areas. Nitrogen-rich natural gases usually have higher 3He/4He ratios(several times of the atmospheric value),and some times a higher concentration of carbon dioxide. Nitrogen enriched in natural gases may be mostly derived from the deep-earth, while ntrogen whith Lower concentration in natural gas in the stable platform is mianly generated from sedimentary organic matter. Because nitrogen isotope ratios of natural gases are similar to those of many nitrogen-bearing matters and there are little isotopic-geochemical data of nitrogen available, it is too difficult to ascertain some limits of δ15N value to classify natural gases as carbon isotope data.
出处
《沉积学报》
CAS
CSCD
北大核心
1996年第1期143-148,共6页
Acta Sedimentologica Sinica
关键词
天然气
氮同位素
地球化学
natural gas
nitrogen isotope
geochemistry
China
