塔中地区天然气氦、氩同位素地球化学特征  

Helium and argon isotopic compositions of natural gases in the Tazhong area,Tarim Basin

作　　者：张殿伟 刘文汇[2] 郑建京 王晓锋 南青云 

机构地区：[1]中国科学院兰州地质研究所气体地球化学实验室 [2]中国石化石油勘探开发研究院

出　　处：《石油勘探与开发》2005年第6期38-41,共4页Petroleum Exploration and Development

基　　金：国家"973"项目(2001CB209100)

摘　　要：氦同位素组成对大构造背景下的构造演化特征具有指示性,而对同一盆地内部较小区块的构造演化差异特征指示性不明显。塔中地区天然气的3He/4He组成具有典型壳源天然气特征,和塔里木盆地整体大地构造背景一致。与中国其他油气区寒武系-奥陶系天然气氩同位素组成相比,塔中地区天然气氩同位素40Ar/36Ar组成有一定特殊性,原因是该区中、下寒武统和中、上奥陶统烃源岩中氩的母体元素钾的丰度较低。利用元素衰变原理估算塔中地区天然气40Ar的母体元素钾的百分含量表明,塔中地区中、下寒武统和中、上奥陶统烃源岩中的泥质和泥质条带对该区天然气具有重要贡献。Helium isotopic compositions in natural gases have a good relationship with geology tectonic background, which indicate the features of tectonic evolvement in a great region but don＇t work for a small region in the same basin. The 2^ He/4^He ratio of natural gas in the Tazhong area, Tarim Basin, has typical crust source characteristics, and is consistent with the tectonic background in the basin, The 40^Ar/36^ Ar ratio of the gases in the Tazhong area is different from that in other basins with Cambrian-Ordovician source rocks, which could be caused by the low potassium abundance in Cambrian Ordovician source rock in the Tazhong area. The calculation of potassium abundance indicates that the argillite and argillaceous stripe in Cambrian Ordovician source rocks make significant contribution to natural gases in the study area.

关 键 词：3^He/4^He比值 构造演化 氩同位素组成 钾丰度 塔里木盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]