苯、甲苯碳同位素组成作为气源对比新指标的研究  

Carbon isotope composition of benzene and toluene as a new index for correlation of gases with their source rocks

作　　者：蒋助生[1] 罗霞[1] 李志生[1] 张英[1] 潘贤庄 

机构地区：[1]中国石油天然气集团公司石油勘探开发科学研究院廊坊分院,河北廊坊065007 [2]中国海洋西部石油公司研究院,广东湛江524057

出　　处：《地球化学》2000年第4期410-415,共6页Geochimica

摘　　要：利用热模拟与在线同位素分析技术研究了天然气与源岩中的苯和甲苯的碳同位素组成变化特征 ,发现热成熟度和运移效应对苯、甲苯碳同位素组成影响较小。同一类型气源岩热模拟产物中苯、甲苯同位素组成受热成熟度的影响不大。在400～600℃热模拟实验中 ,除个别点外 ,变化小于1‰ ,说明它们基本上不受热成熟度的影响。不同层位气源岩苯、甲苯碳同位素组成有明显区别,大多相差3‰以上。甲苯脱吸附实验表明 ,甲苯碳同位素组成在脱吸附过程中基本上不发生变化 ;而热成熟度和运移效应对C1～C2 碳同位素组成影响较大 ,同一样品在不同热成熟度阶段甲烷碳同位素组成的变化可达10‰左右 ,乙烷碳同位素组成的变化可达5‰左右,甲烷的扩散效应可使甲烷碳同位素组成变化达15‰左右 ,吸附效应可使甲烷碳同位素组成变化达20‰左右。苯、甲苯碳同位素组成可作为气源对比的有效指标,利用苯。The combination of thermal simulation and on line carbon isotope composition analytical technique is applied to investigate the characteristics of carbon isotope composition of benzene and toluene in natural gases and source rocks in this paper. It is found that the carbon isotope composition of benzene and toluene are few affected by the thermal maturity and migration which may make a notable impact on the carbon isotope composition of CH4 and C2H6 When a rock is thermally simulated from 400 ℃to 600 ℃, the variation of benzene and toluene from same types of pyrolysed rocks is within 1‰except few data and is more than 3‰from different types of pyrolysed rock, while the variation of carbon isotope composition of CH4 from same types of pyrolysised rock is about 10‰, C2H6 is about 5‰. The variation of carbon isotope composition of CH4 is about 15‰in diffusion experiment and about 20‰in adsorption experiment. The variation of carbon isotope composition of toluene is less than 1‰in adsorption experiment. The carbon isotope composition of benzene and toluene can be used as a new index of correlation of gases with their source rocks. It is turned out that they are good index in correlatinggases and source rocks in the basins in China, such as Tarim Basin.

关 键 词：苯 甲苯 碳同位素组成 气源对比 天然气 

分 类 号：P593[天文地球—地球化学] P618.130.1[天文地球—地质学]