长岭断陷无机成因天然气的判别与分布特征  

Discrimination and Distribution Characteristics of Inorganic Natural Gas in Changling Fault Depression

作　　者：周卓明[1,2] 湛小红[3] 李贶[2] 

机构地区：[1]成都理工大学能源学院,四川成都610059 [2]中国石化石油勘探开发研究院无锡石油地质研究所,江苏无锡214151 [3]西南石油大学资源与环境学院,四川成都610500

出　　处：《石油天然气学报》2012年第4期31-35,165,共5页Journal of Oil and Gas Technology

基　　金：中国石油化工股份有限公司科技开发项目(P10024)

摘　　要：通过对松辽盆地长岭断陷烷烃气和CO2碳同位素资料的分析,认为该地区存在无机成因天然气。烃类气体中具有重碳同位素异常(δ13 C1>-30‰)和负碳同位素系序(δ13 C1>δ13 C2>δ13 C3>δ13 C4)的同位素分布特征,CO2碳同位素分布在-4.63‰～-16.7‰,部分天然气表现出无机成因烃类气体的特点。3 He/4 He值为0.88Ra,指示有幔源氦的存在,说明该区天然气可能是壳幔混源。长岭断陷天然气藏中不仅无机成因烷烃气由北向南逐渐减少,且幔源CO2也表现出从西北向东南含量明显减少,与区域构造、断裂走向和火山岩密切相关等与无机成因烷烃气相似的分布特征。On the basis of analyzing the carbon isotopes of paraffin gas and CO2,in the Changling Fault Depression of Songliao Basin,it was considered that there existed inorganic natural gases in the depression.The abnormal of carbon isotopes(>-30‰) and the reverses of isotopic series(δ13C1>δ13C2>δ13C3>δ13C4)had the characteristics of inorganic hydrocarbon gases.The δ13CO2 value of natural gases was between-4.63‰ and-16.7‰,some gases presented the characteristics of inorganic generated hydrocarbon gases.The 3He/4He was 0.88 Ra,it reflected that there existed the mantle-derived helium,and the gases in the area were derived from mixing sources of crust and mantle.In Changling Fault Depression,the inorganic gas in gas reservoirs is reduced gradually from the north to south while the mantle-derived CO2 content is reduced significantly from the southeast to northwest,it presents similar distribution trend with the inorganic generated gas.The distribution of inorganic gas and mantle derived CO2 are closely related with regional tectonics,fault strike and volcanic rocks.

关 键 词：长岭断陷 无机成因气 碳同位素 分布特征 

分 类 号：P618.13[天文地球—矿床学]