吐哈盆地侏罗系沉积特点及油气资源

Sedimentary environments and petroleum resource of Jurassic rock in the Turpan Basin

目的 研究吐哈盆地侏罗系沉积发育特点及油气资源。方法 采用沉积岩石学、沉积相分析及有机地球化学方法对本区侏罗系沉积环境及油气资源进行探讨。结果 本区下、中侏罗统由灰、灰绿色含砾细粒沉积物组成,沉积环境以湖泊 沼泽相为主;上侏罗统由杂色粗粒沉积物组成,以山麓河流相环境为主及干旱气候为特征;砂岩主要属岩屑砂岩及长石岩屑砂岩,成分成熟度与结构成熟度均较低,源自盆地南北两侧;南侧觉罗塔格山是盆地的主要物源区,沉积物搬运方向总是由南向北,在盆地南部形成辫状及曲流河三角洲沉积,在盆地北部发育冲积扇三角洲堆积。结论 本区侏罗系构成该盆地重要的生储盖组合。

Aim The Jurassic sediments form the most widely distributed and thickest part of the Turpan Basin, as well as the most important productive sequences of oil, gas and coal, sedimentologic research is very important for the petroleum exploitation in this area.Methods Based on sedimentologic and organic geochemistry study on the Jurassic sediments.Results The Lower and Middle Jurassic sediments consist of grey and green fine clastic coalbearing rocks which were deposited in a lacustrine-swamp environment. The Upper Jurassic consists of variegated coarse clasts rocks, reflecting piedmont-fluvial environment with arid climate. The sandstones belong mostly to greywacke and feldspar greywacke, their compositional and textural maturity are generally low. The sediments were derived from southern and northern parts of the basin. The Jueluotage mountain was the dominant source rock region for the Turpan Basin, and the paleocurrent directions were from south to north. There are some braided and meandering fluvial deltas in the south of the basin, while the alluvial deltas deposited on the north margin of the basin.Conclusion The Jurassic sediments are the important petroleum exploitation zone.