吐哈盆地二叠系—侏罗系流体包裹体研究

A study on fluid inclusion of Permian-Jurassic in Turpan-Hami basin.

为查明吐哈盆地油气的成因、形成时期及运移情况 ,在进行盆地热史研究时采用了流体包裹体研究方法。该盆地侏罗系与前侏罗系砂岩石英颗粒中的流体包裹体形成温度为 60～1 95℃ ,主要在构造运动中沿微裂隙进入储集层 ,多形成于半咸水的还原环境 ,反映煤系地层湖相低等生物和陆相高等植物混合成烃的特点。有机包裹体均一温度测定结果显示 ,侏罗纪古地热梯度由盆地西部的 2 .76℃ / 1 0 0m向东逐渐变为 3 .41℃ /1 0 0m ,盆地南带二叠纪地热梯度约为 3 .3 7～ 4.1 2℃ / 1 0 0m。盆地北部的台北凹陷和盆地西南部的托克逊凹陷油气成熟及运移时期为侏罗纪—第三纪 ,盆地南部的台南凹陷油气成熟及运移时期为三叠纪。吐哈盆地三叠纪、侏罗纪的古流体势均呈现北高南低的趋势 ,反映了油气自北向南的运移规律。图 4表

The research method of fluid inclusion has been adopted in the research procession of geothermal history of Turpan Hami basin in order to understand the origin, formation period and migration of oil and gas. Research results of fluid inclusion distributed in quartzs in Jurassic and pre Jurassic in Turpan Hami basin represent the features of the mixed hydrocarbon generation.The dominant hydrocarbon generating matters come from lacustrine low forms of life and high plants and their forming environment is of brackish and reduction. Measurement of homogenization temperature indicates the formation temperatures of organic inclusions are in the range of 60 195℃. The geothermal gradients of the Jurassic mostly fall from about 2.76℃/100m in the western basin to 3.41 ℃/100m in the eastern basin. The geothermal gradients in the Permian in the south of the basin are in the range of 3.37 4.12 ℃/100m. The maturing and migrating time of oil and gas is in the times of Jurassic Tertiary in Taibei sag located in the north of the basin and Toksum sag located in the southwest of the basin and in the times of Triassic in Tainan sag located in the south of the basin. The paleo fluid potential in the Triassic and Jurassic all shows the trend of being higher in the north than in the south, and indicates a regularity of oil and gas migration from north to south of the basin. The organic inclusion in these areas entered reservoirs along microfractures in tectonic movements.