摘要
产于江汉盆地潭口地区上第三系广华寺组之浅层天然气以甲烷为主(>95%),重烃含量低(<1%),含少量非烃类气体氮和二氧化碳,具有干气的组成特征。天然气中甲烷碳同位素组成较轻,δ^(13)C_1值为-52.03‰,分布在生物气与热解气的混合区内。其天然气的主要成因是下伏潜江组偏腐泥型母质的未成熟—低成熟源岩生成的油气,通过不整合面或断层运移到上第三系广华寺组之中,经生物化学作用和微生物降解作用形成的生物气与热解气相互混合的结果。
The shallow natural gas in the Upper Tertiary Guanghuasi group in Tan- kou area in Jianghan basin is mainly composed of CH_4(>95%),with low hea- vy hydrocarbon content (<1%) and a low % of nonhydrocarbon gas—N_2 and CO_2.The gas has a compositional characteristics of dry gas.C-isotopes in CH_4 is fairly light with a δ^(13)C_1 of -52.01%,such gas lies within the range of a mixture of biogenic gas and pyrolytic gas. This paper suggests that the natural gas in this area be mainly originated from rather saprop(?)lic source materials in the low to unmatured source rock in the underneath Qianjiang group.It migrated into the Upper Tertiary Gu- anghuasi group through unconformities or foults and then degraded by microo- rganism accompanied by some biochemical reactions to form biogenic gas which is mixed with pyrolytic gas to form the present natural gas in the reservoir.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
1990年第6期13-20,共8页
Petroleum Exploration and Development
