天然气水合物发现区和潜在区气源成因  

Gas Sources Genesis in the Gas Hydrate Discoveries and Potential Areas

作　　者：龚建明[1] 张敏[2] 陈建文[1] 李谨[3] 陈立英[1] 成海燕[1] 

机构地区：[1]青岛海洋地质研究所海洋油气资源与环境地质重点实验室,山东青岛266071 [2]长江大学地球化学系,湖北荆州434023 [3]中国石油勘探开发研究院廊坊分院,河北廊坊065007

出　　处：《现代地质》2008年第3期415-419,共5页Geoscience

基　　金：国家自然科学基金项目(40576059);国土资源部海洋油气资源与环境地质重点实验室项目(MRE200805)

摘　　要：为探讨天然气水合物发现区的气源成因,对ODP 204航次4个站位58个沉积物样品进行5个温度点的生气量模拟实验,对各温度点产生的气体进行同位素测定。测试结果显示,在低温阶段(25℃、35℃、45℃),甲烷的δ13C明显偏大,一般大于-40‰,显示出热解成因气的特征;而高温阶段(55℃)甲烷的δ13C为-75.5‰,显示出明显的生物成因气的特征。结合东沙海域天然气水合物潜在区气源成因的讨论,可以得出如下结论:天然气水合物的气源成因受控因素多,需要综合多种指标进行判别。In order to study the gas sources genesis in gas hydrate discoveries and potential areas, gas-genera- ting amounts of 58 sediment samples from 4 sites of ODP 204 Expedition have been modeled by 5 temperature points, gas chromatography is used to test the isotope from different temperature points. The test results show that methane carbon isotope （δ^13C） is evidently heavier among the lower temperature modeling points, commonly larger than -40‰, displaying the isotopic feature of thermogenic gas; while the lighter δ^13C could reach to -75.5‰ when the modeling temperature is higher than 55 ℃, showing the isotopic feature of biogenic gas. Integrated with the discussion of gas genesis of Dongsha potential area, the conclusions could be drawn as follows, gas genesis could be controlled by many factors, and correct gas genesis could be got through the combination of other factors besides the methane carbon isotope.

关 键 词：气源成因 Δ^13C 烃类气体 模拟 东沙海域 ODP 204航次 

分 类 号：P618.13[天文地球—矿床学] P744.4[天文地球—地质学]