川西坳陷天然气地球化学及成藏特征  

Characteristics of natural gas geochemistry and accumulation in Western Sichuan Depression

作　　者：秦胜飞[1] 陶士振[1] 涂涛[2] 魏小薇[2] 宋明玮[2] 

机构地区：[1]中国石油勘探开发研究院 [2]中国石油西南油气田分公司勘探开发研究院

出　　处：《石油勘探与开发》2007年第1期34-38,54,共6页Petroleum Exploration and Development

基　　金："十五"国家重点科技攻关项目(2001BA605A-06)

摘　　要：川西坳陷广泛发育上三叠统煤系烃源岩,为煤成气成藏提供了充足的气源。天然气以低含非烃气为特征,不同气藏天然气干燥系数差别明显,组分运移分馏现象明显。天然气成因类型主要是煤成气,只有中坝气田雷口坡组气藏为油型气,并含有少量H2S气体。川西坳陷经历了多期成藏,但主要成藏期发生在燕山期,后经过喜马拉雅期的逆冲断裂作用,浅层储集层被改造,形成次生气藏。气藏分布明显受古隆起控制,并且在构造强活动带发育浅层次生气藏,隐伏断裂在次生气藏形成过程中起重要作用。天然气主要分布在中、上组合,受储集条件控制,气藏形态主要呈透镜体。The widely developed Upper Triassic coal-measure source rocks have provided sufficient gases for the pool formed in the Western Siehuan Depression. The gases have very low non-hydrocarbon contents and different dry coefficients with distinct component fractionation between reservoirs. The gases in the reservoirs are mainly coal-formed. Only the T2l reservoir in Zhongba gas field is of oil-type with some H2S in it. The Western Sichuan Depression has endured several times of gas accumulation, mainly Laramide orogenies. During Hymalaya thrust movement, the shallow reservoirs have been improved and thus secondary gas reservoirs could be formed. The reservoirs are obviously controlled by paleo-uplift, and the shallow secondary reservoirs are usually distributed in the areas that have endured strong tectonic movement. The concealed fractures have acted an important role during the secondary reservoir formation. The gases are distributed in middle and upper lens-shaped reservoirs due to preservative condition.

关 键 词：川西坳陷 天然气 煤成气 次生气藏 地球化学特征 成藏 

分 类 号：TE122.1[石油与天然气工程—油气勘探]