A Cause Analysis of the High-Content Nitrogen and Low-Content Hydrocarbon in Shale Gas: A Case Study of the Early Cambrian in Xiuwu Basin, Yangtze Region
Table 3
Summarized characteristics of stable nitrogen isotope of nitrogen in natural gas of different sources (modified from Zeng [42] and Liu et al. [43]).
Sources
Genesis mechanism
Nitrogen isotope (δ15N≈)
Atmosphere
Carried by surface water, diffused underground
0‰
Deep crust-upper mantle
Thermal reactions and radiation effects in the Earth’s core
-2‰~+1‰
Sedimentation
Metamorphism
High temperature metamorphism of nitrogenous minerals
+1‰~+3.5‰
Microbial denitrification
Generated by interactions between organisms and organic matter
