鄂尔多斯盆地东南部上古生界流体包裹体特征及其意义

The characteristics of fluid inclusions in Upper Paleozoic of Southeast area at Ordos Basin and their significance

采用单偏光、荧光显微镜、显微冷热台测温观察和激光拉曼光谱分析等方法,以成岩矿物世代内流体包裹体组合（FIA）及其伴生盐水包裹体均一温度等参数来综合判定鄂尔多斯盆地东南部上古生界天然气充注特征,对东南部上古生界石盒子组盒8段、山西组储层流体包裹体进行系统研究,归纳流体包裹体岩组分、相学、均一温度和冰点温度特征,结合盆地热埋藏史分析研究储层内烃类充注史.研究认为,与气态烃伴生的盐水包裹体均一温度范围为100～170℃.赋存在第一期石英加大边内的包裹体可反映第一期充注特征,盐水包裹体均一温度介于105～120℃,包裹体气相组分以CO2为主,少量CH4,推测充注时间为190～170 Ma;赋存第二期石英加大边内的包裹体可反映第二期充注特征,盐水包裹体均一温度介于135 ～155℃,包裹体气相组分以CH4为主,推测充注时间为145～110 Ma.研究区上古生界天然气运移富集成藏是一个相对漫长且连续的过程,以早白垩世为主要充注期.

With methods of polarizing and fluorescence microscope, heating/freezing system and Laser Raman et al, characteristics of Upper Paleozoic gas injection in southeastern basin can be defined according to parameters of FIA （ Fluid Inclusion Assembly） and homogenization temperature of concomitant aqueous inclusion in diagenetic miner- als. A systematic research has been done on the fluid inclusion in Shanxi Formation of Paleozoic, Southern Ordos Basin, and conclude the characteristics of petrography, homogenization temperature, ice point and component of fluid inclusion, besides, combined with thermal evolution of basin, forecast hydrocarbon injection history in reser- voir. It is concluded that the homogeneous temperature of aqueous inclusion, associated with gaseous hydrocarbon, ranges from 100 to 170℃. The first injection can be reflected by fluid inclusion occurred in first stage quartz out- growth edges as follows, the homogenization temperature of aqueous inclusion ranges from 105 to 120℃, gas com- ponent of inclusion is mainly CO2, CH4 is seldom, injection stage is inferred as 190 - 170 Ma. The second injec- tion can be reflected by fluid inclusion occurred in secondary quartz outgrowth edges as follows, the homogenization temperature of aqueous inclusion ranges from 135 to 155℃, gas component is mainly CH4, injection stage is in- ferred as 145 ~ 110 Ma. It is concluded that Paleozoic long, and mainly developed in Early Cretaceous. gas accumulation in study area is continuous and relatively