摘要
借助于显微镜的单偏光和荧光,对鄂尔多斯盆地志丹地区山西组致密砂岩的岩石学特征进行观察,同时,采用显微冷热台对石英次生加大边中的包裹体进行测温,并使用激光拉曼光谱对包裹体的组分进行分析。盆地模拟研究发现,志丹地区山西组致密砂岩石英次生加大边中发育无机盐水包裹体、含烃盐水包裹体、气液态烃包裹体和气态烃包裹体4种类型包裹体;赋存在Ⅰ期石英次生加大边内的盐水包裹体均一温度在80~100℃,冰点温度在-4^-2℃,推测形成时间为200×10~6—190×10~6a;Ⅱ期石英次生加大边的盐水包裹体均一温度在105~125℃,冰点温度在-6^-4℃,包裹体气相组分以CO_2为主,少量C_2H_6,推测第一期天然气充注时间及砂岩初次致密化时间为190×10~6—160×10~6a;Ⅲ期石英次生加大边中的盐水包裹体均一温度在135~155℃,冰点温度在-10^-8℃,包裹体气相组分以CH_4和C_2H_6为主,伴随有大量后期高成熟天然气充注,推测天然气成藏及砂岩进一步致密化的时间为160×10~6—140×10~6a,天然气的充注伴随着砂岩的后期致密化发育。
By means of polarized?light and fluorescence microscopes,petrological characteristics of the tight sandstones of Shanxi formation in Zhidan area,Ordos basin are observed.Meanwhile,temperatures of the inclusion in the quartz overgrowth edges are measured by using microscopic heating?freezing stages and components of the inclusion are analyzed with laser Raman spectroscopy.The study shows that four types of inclusions are developed in the quartz overgrowth edges of the tight sandstones in Shanxi formation of Zhidan area,namely,inorganic brine inclusion,hydrocarbon?bearing brine inclusion,gaseous and liquid hydrocarbon inclusion,and gaseous hydrocarbon inclusion.The homogenization temperature of the brine inclusion occurred in the quartz overgrowth edges of StageⅠranges from80℃to100℃and its freezing temperature is-4^-2℃.Based on which,it is assumed that the quartz overgrowth edge was formed200×106~190×106years ago;brine inclusion in the quartz overgrowth edges of StageⅡhas a homogenization temperature of105~125℃and freezing temperature of-6^-4℃,whose gaseous components are dominated by CO2with minor C2H6,indicating the time for StageⅠnatural gas charging and initial sandstone densification was190×106~160×106years ago.The homogenization temperature and freezing temperature of the brine inclusion in the quartz overgrowth edges of StageⅢare135~155℃and-10^-8℃,respectively.The gasceous components are dominated by CH4and C2H6,accompanied by large amount of high?matured natural gas charging at the late stage.Then it is assumed that the time for natural gas accumulation and further sandstone densification occurred160×106~140×106years ago.Natural gas charging was accompanied by late?stage sandstone densification.
作者
李艳霞
刘洁琪
LI Yanxia;LIU Jieqi(Xi’an Shiyou University, Xi’an, Shaanxi 710065, China)
出处
《新疆石油地质》
CAS
CSCD
北大核心
2017年第3期264-268,共5页
Xinjiang Petroleum Geology
基金
国家自然科学基金(41372148)
