苏里格气田西区盒8段储层流体包裹体特征与成藏期次

Fluid Inclusion Characteristics and Hydrocarbon Accumulation Period of He8 Member Reservoir in the Western Area of Sulige Gasfield

通过单偏光显微镜观察、激光拉曼光谱分析及显微测温,对苏里格气田西区16口井50块盒8段储层流体包裹体样品进行了综合测试分析,总结了流体包裹体的岩相学特征,并依据流体成分将包裹体细分为6种类型。分别测试了不同层位、不同产状内与烃类包裹体伴生的盐水包裹体的均一温度、盐度。结果显示:盒8段储层伴生盐水包裹体的均一温度分布在90~180℃,温度主频段分布在120~170℃;石英次生加大边中的伴生盐水包裹体主峰温度比愈合裂隙及微裂隙中的略低,且不存在明显界限。在包裹体均一温度、盐度分析的基础上,结合研究区埋藏史-热史-生烃史,认为苏里格气田西区盒8段天然气为一期成藏,成藏期可依据伴生盐水包裹体均一温度分布特征划分为初始充注期和主充注期2个阶段。初始充注期伴生盐水包裹体均一温度区间为90~120℃,对应于220~160 Ma的中三叠世末—中侏罗世末,主充注期伴生盐水包裹体均一温度区间为120~170℃,对应于160~100 Ma的晚侏罗世—早白垩世末。

Based on the observation of polarizing and fluorescence microscope,laser Raman spectrum analysis and micro-thermometry,the fluid inclusions of 50 sandstone samples of He8 member reservoir from 16 wells in the west of Sulige gas-field are comprehensively tested and analyzed,and the petrographic characteristics of the fluid inclusions in the study area are summarized.According to the fluid composition,the fluid inclusions are divided into 6 types.The homogenization temperature and salinity of brine inclusions associated with hydrocarbon inclusions in different horizons and occurrences were measured.The results show that the homogeneous temperature of the associated brine inclusions in He 8 reservoir is 90~180℃,and it mainly distributes in 120~170℃.The main peak temperature of the associated brine inclusions in the secondary enlarged quartz edge is slightly lower than that in the healing cracks and micro cracks,and there is no obvious boundary between them.On the basis of research of homogeneous temperature,salinity and burial history-thermal history-hydrocarbon generation history,it is held that the natural gas of He8 member in the west area of Sulige gas field accumulated in one stage,and the natural gas accumulation process can be divided into two stages:initial charging stage and main charging stage.In the initial charging stage,the homogeneous temperature of the brine inclusions associated with hydrocarbon inclusions is 90~120℃,corresponding to the period from middle Triassic to middle Jurassic(220~160 Ma).In the primary charging stage,the homogeneous temperature of thebrine inclusions associated with hydrocarbon inclusions is 120~170℃,corresponding to the period from late Jurassic to early Cretaceous(160~100 Ma).