川西坳陷天然气中非烃气地球化学特征及应用  

Geochemical Characteristics of nonhydrocarbon in Natural Gas in West Sichuan Depression and Its Implications

作　　者：王鹏[1] 沈忠民[1] 刘四兵[1] 吕正祥[1] 王乐闻[2] 

机构地区：[1]成都理工大学油气藏地质及开发工程国家重点实验室,四川成都610059 [2]中国石化上海海洋油气分公司研究院,上海200120

出　　处：《天然气地球科学》2014年第3期394-401,共8页Natural Gas Geoscience

基　　金：国家自然科学基金(编号:41172119)资助

摘　　要：对川西坳陷天然气中非烃气地球化学特征进行了分析,并应用非烃地球化学特征对该区天然气成因、成熟度、运移与气源等特征进行了研究。研究区天然气中非烃气体以CO2、N2和稀有气体为主,CO2主要来源于碳酸盐矿物溶解,N2主要来源于有机质成熟与高成熟阶段的热转化过程,稀有气体主要来源于地壳元素衰变过程。非烃气体证据表明,研究区天然气为壳源热成因气,主要处于成熟与高成熟阶段。非烃示踪研究区天然气运移结果表明,N2是天然气垂向运移的有效指标,而当CO2主要来自碳酸盐矿物溶解时,CO2则可能不能有效地示踪天然气垂向运移。利用稀有气体同位素进行气源分析,从非烃的角度证实了研究区上三叠统天然气来自上三叠统烃源岩中煤岩与泥岩的共同贡献。The geochemical characteristics of nonhydrocarbon in natural gas in western Sichuan Depression were analyzed to investigate the origin, maturity, migration and source of natural gas in the study area. The nonhydrocarbon gases mainly contain CO2 ,N2 and noble gas. CO2 mainly comes from the dissolution of carbonate mineral, N2 mainly originates during the thermal evolution of organic matter at mature and high mature stages, and noble gas mainly originates during the radiation process of element in crust rock. The evidence of nonhydrocarbon indicates that natural gas is thermogenic gas derived from the crust and is mainly at mature and high mature stages. The results of gas migration by nonhydrocarbon trace method show that N2 is an effective index for natural gas＇s vertical migration,however,when CO2 mainly comes from the dissolution of carbonate mineral, CO2 may be not able to trace the migration of natural gas effectively. The analysis of noble gas demonstrates that the Upper Triassic natural gas is mixed gas from argillaceous source rocks and coal of Upper Triassic source rock.

关 键 词：非烃 天然气 成因 运移 气源 川西坳陷 

分 类 号：TE132.1[石油与天然气工程—油气勘探]