焉耆盆地三叠系—侏罗系含油气系统

Triassic Jurassic petroleum system in Yanqibasin .

焉耆盆地处于塔里木盆地与吐哈盆地之间，构造格局为两坳（ 和静坳陷、博湖坳陷） 一隆（ 焉耆隆起） ，晚古生代为南天山前陆盆地的组成部分（ 早二叠世回返） ，中三叠世至侏罗纪形成南深北浅的箕状断陷，白垩纪至古新世隆升，始新世以来成为南天山类前陆盆地。焉耆盆地中生界的成熟烃源岩为三叠系小泉沟群和下侏罗统八道湾组的煤系地层（ 主要分布于博湖坳陷） ，构成博湖坳陷三叠系—侏罗系含油气系统（ ！） ，燕山中期（ 侏罗纪末） 第一次成烃充注，喜山期（ 晚第三纪） 第二次成烃充注。根据博湖坳陷北部凹陷和南部凹陷油气生、运、聚的差异，其含油气系统可划分为北部凹陷运聚子系统和南部凹陷运聚子系统，论述了二者地质事件和关键时刻。北部凹陷运聚子系统石油资源量为１ ．８４×１０８ｔ，天然气资源量为５２５ ×１０８ｍ３ ，是焉耆盆地油气勘探的主要领域（ 已发现的宝浪油田和本布图油田均位于北部凹陷） 。图５ 参３（ 王孝陵摘）

Yanqi basin is located between Tarim and Turpan Hami basins,its structural geometry is characterized by 2 depressions (Hejing, Bohu depressions) and 1 arch (Yanqi arch) .It’s Late Paleozoic is a part of South Tianshan fore land basin (being returning back in Early Permian) ;it formed dust pan sag being deepin south and rather shallow in north in Middle TriassictoJurassic,arched upin Cretaceousto Palaeocene ,and created the South Tianshan foreland like basin since Eocene. Mesozoic matured hydrocarbon source rocks of the Yanqi basin are Xiaoquan Group in Triassic and Badaowan coaliferous Formationsin LowerJurassic (mainly in Bohu depression) , forming Triassic Jurassic petroleum system in Bohu depression. First hydrocarbon generation, migration and accumulation happened in Middle Yanshan (Late Jurassic) and secondonesoccurredin Himalayan (Late Tertiary) .Based onthe differencesin the generation ,migration and accumulationinthe northern and southern sagsin Bohu depression petroleum system is divided into northern and southern sag subsystems and their geological events and key times in these subsystems are dealt with . It is estimated that in northern subsystem the oilrecourse may be1 .84 ×108tandthe gasresource may be525×108m3 and thusthis subsystem should be the main petroleum exploration region (both Baolang oil field and Benbutu oil field discovered already are lied in northern sag) .