摘要
威远气田位于四川盆地南部,受乐山—龙女寺背斜轴部构造控制。储集层为元古界震旦系灯影组白云岩夹薄层泥岩和陡山沱组泥岩,直接盖层为寒武系九老洞组泥岩,两者均为烃源岩,构成寒武系-震旦系含油气系统,基底为新元古代澄江期花岗岩。区内所有地层和花岗岩的裂隙中皆见有天然气。该气田是我国乃至全世界储集层最古老的大型气田,具有如下特征:①背斜轴部南移控气的规律;②天然气R0值和He,Ar含量随地质年代增大呈现积累效应;③天然气的主要成分CH4与C2H6,He,H2S,CO2,N2相关性显著;④δ(13C1),δ(13C2)和δ(13Cco2)同位素非常相似;⑤天然气具有高氦、高氩含量;⑥多期流体活动成藏印迹明显;⑦气藏水具有深层混源成因特点;⑧古油藏沥青地球化学等特征表明威远气田为深部幔壳混源成因类型。
Weiyuan gas field in the south of Sichuan Basin is a large gas field with the most ancient reservoir in China and even the in the world controlled by axis of Leshan-Longnusi anticline.Dolomite and thin interlayers of mudstone of Proterozoic Sinian Dengying Formation and mudstone of Doushantuo Formation are the gas accumulation strata.Direct cap rock is mudstone of Cambrian Jiulaodong Formation.The cap and accumulation strata are all the hydrocarbon generation rocks.Granite of Late Proterozoic Chengjiang period is the basement.All strata and fracture in granite contain natural gas in the region.The gas field is characteristic of：①gas controlled by the anticline axis southward shift;② showing natural gas R0 value and He,Ar accumulation effect with ageing of the stratum;③ high correlation among C2H6,He,H2S,CO2 and N2,CH4,the main component of natural gas;④ similar δ13C1,δ13C2 and δ13Cco2 value;⑤high He and Ar content;⑥ multiple fluid flowing and trapping;⑦ mantle-crust-derived water under;⑧ asphalt geochemistry of mantle-crust mixture
出处
《地质找矿论丛》
CAS
CSCD
2011年第1期63-73,共11页
Contributions to Geology and Mineral Resources Research
基金
中石化勘探南方分公司项目<南盘江地区MT在EMAP资料处理与解释>资助
关键词
震旦系储集层
幔壳混源
背斜轴部控气
威远气田
四川省
Sinian reservoir
mantle-crust mixture
anticline-axis-controlled-gas
Sichuan basin
Weiyuan gas field
