摘要
分析塔里木盆地海相天然气碳同位素组成 ,发现天然气的乙烷碳同位素值域分布范围较大 ( - 43‰～- 2 9‰ ) ,并且具有很强的母质继承性。据此并结合天然气甲烷碳同位素组成变化特征 ,将该盆地海相天然气分成 4类。第一类 :δ13 C1值小于 - 40‰ ,δ13 C2 值小于 - 3 7‰ ,主要来源于寒武系—下奥陶统腐泥型母质 ,分布于塔中主垒带、英买力和东河塘地区 ;第二类 :δ13C1值小于 - 40‰ ,δ13 C2 值大于 - 3 4‰ ,主要来源于中、上奥陶统偏腐殖型母质 ,分布于塔中北斜坡、巴楚、东河塘及雅克拉等地区 ;第三类 :δ13 C1值大于 - 40‰ ,δ13 C2 值为 - 3 9‰～ - 3 5‰ ,主要来源于寒武系—下奥陶统腐泥型母质 ,并受热成熟作用影响 ,主要分布在轮南—吉拉克地区 ;第四类 :δ13 C1值大于 - 40‰ ,δ13 C2值大于 - 3 5‰ ,主要来源于寒武系—下奥陶统腐泥型母质 ,同时混入有中、上奥陶统或石炭系偏腐殖型母质生成的气 ,主要分布于桑塔木断垒带及解放渠东—吉拉克地区。图 1表 3参 4(梁大新摘 )
Through the analysis of carbon isotope of marine gas in Tarim basin, it is found that the δ 13C values of ethane changes largely, ranging from-43‰ to 29‰,and shows an inheritance of matrix. The marine gas may be divided into four types according to the δ 13C values of ethane and other parameters, which are Type Ⅰ: δ 13C 1<-40‰, δ 13C 2<-37‰, they came chiefly from the Cambrian Lower Ordovician sapropelic rocks; Type Ⅱ: δ 13C 1<-40‰, δ 13C 2>-34‰, the came mainly from the Middle Upper Ordovician skewed humic rocks; Type Ⅲ: δ 13C 1>-40‰, -39‰< δ 13C 2<-35‰, they originated from the Cambrian Lower Ordovician sapropelic rocks, and affected by the thermal maturation and Type Ⅳ: δ 13C 1>-40‰, δ 13C 2>-35‰, they derived from the Cambrian Lower Ordovician sapropelic rocks, and mixed by the gas coming from the Middle Upper Ordovician or Carboniferous skewed humic rocks. In addition, the distribution of various kinds of natural gas is discussed.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
1999年第6期27-29,共3页
Petroleum Exploration and Development
关键词
天然气
海相天然气
乙烷碳
同位素
分类
成因
Trim basin, Marine facies, Natural gas, Type, Carbon isotope, Composition, Change
