摘要:
焉耆盆地三工河组流体包裹体具有丰度低、个体小的特征,并以液态烃相包裹体为主,主要分布在石英颗粒的溶孔或溶缝当中。结合盆地成岩作用和有机质演化历史分析,认为它们形成于侏罗纪晚期的以压溶和溶蚀作用为特征的晚成岩作用阶段。包裹体均一温度呈双峰型分布,具有 10 1~ 110℃和 12 1~ 130℃两个区间,结合焉耆盆地的埋藏史和盆地的热史,这两个温度区间分别对应于晚侏罗世和侏罗纪末期。包裹体组份特征分析也证实该地区存在两期包裹体,并且包裹体组分主要是在烃源岩低成熟阶段形成的。可以认为,焉耆盆地三工河组储层的流体包裹体主要是在晚侏罗世烃源岩的低成熟阶段和侏罗纪末期烃源岩的成熟阶段形成。
Abstract:
The fluid inclusions in Sangonghe Formation of Jurassic in Yanqi basin Northwest China were investigated. The fluid inclusions in Sangonghe Formation , which mostly occurred in the dissolution or pressure solution pores of quartz grains, were usually small in their size and low in their abundance. Up to 80% of organic inclusions existed in the state of liquid hydrocarbon phase, only some 20% of them in gaseous and gaseous-liquid hydrocarbon phases. In addition to organic inclusions, there were some saline-aqueous solution inclusions. Combined with the evolution history of the diagenesis and organic matter maturation, the fluid inclusions were mainly formed in the stage of late diagenesis in late Jurassic. The homogenization temperatures of inclusions fell in the temperature interval of 101～130℃, with ranges of 101～110℃ and of 121～130℃ as two peaks. According to the temperature history of Sangonghe Formation, the temperature of 101～110℃ was consistent with the temperature of Sangonghe Formation in late Jurassic and the peak of 121～130℃ with the temperature in the end of Jurassic when the formation reached its deepest burial in geohistory. The composition of hydrocarbon inclusion also showed two peaks in gas chromatogram with one peak in C 18 or C 20 and the other in C 26 or C 27 , which indicated the two formation periods of the inclusion. The maturity indices of inclusion component showed that the inclusions were formed in low mature stage of source rock. In summary, the fluid inclusion of Sangonghe formation of Jurassic in Yanqi basin were mainly formed in two periods, with one in late Jurassic when the source rock of the basin was in low mature stage, and the other in the end of Jurassic when the formation reached its deepest burial and the source rock in mature stage.
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