Abstract: This paper was written based on 1851 C_1-4 data from 8153 gaseous samples taken from 16 petroliferous basins spreading all over China.The isotopic characteristics of alkane gases area 1.δ¹³C values of organic alkane gas increase with the increasing of maturity(R₀).2.The δ¹³C values of synchronous and isogenous methane and its homologues increase with the increasing of carban number of alkane gas molecules.3.Theδ¹³C values of methane and its homologues of coaliferous gas are heavier than that of corresponding component of petroliferous gas from source rocks with the same or similar maturity.4.Part of methane and its homologues components were oxidized by bacteria and resulted in a heavier carbon isotopes in the rest.

摘要： 本文根据中国16个含油气盆地815个气样δ¹³C_1-4的1851个分析数据,探讨了中国有机烷烃气碳同位素特征,认为有机烷烃气的δ¹³C值随成熟度(R₀)增大而增加;有机的同源同期的甲烷及其同系物的δ¹³C值随烷烃气分子中碳数增加而增大;相同或相近成熟度源岩形成的煤成气的甲烷及其同系物的δ¹³C值比油型气的对应组份的δ¹³C值重;甲烷及其同系物中某个或某些组份被细菌氧化后可使其剩余组份的碳同位素变重.

关键词: 碳同位素, 有机质成熟度, 烷烃气, 含油气盆地