准噶尔盆地西北缘存在着众多的地层油气藏,目前对于其油气成藏期次及成藏时间的认识尚存在争议。为此,采集了该区26口钻井的58块流体包裹体样品,利用流体包裹体显微测温技术,结合埋藏史及热演化史分析成果,研究了上述流体包裹体的显微特征和均-温度特征,确定了该区地层油气藏的油气成藏期次,进一步结合该区烃源岩生排烃史和构造发育史,恢复了地层油气藏的成藏过程。结论认为:①晚二叠世-早三叠世,二叠系佳木河组烃源岩生成的成熟油气进入石炭系火山岩储层和二叠系佳木河组、风城组、夏子街组等碎屑岩不整合储层中聚集成藏;②晚三叠世-早侏罗世,二叠系风城组烃源岩生成的成熟油气进入二叠系内部以及三叠系底部不整合砂砾岩储层中聚集。以形成中深部油藏为主;③晚侏罗世-早白垩世,二叠系佳木河组烃源岩生成的天然气和二叠系下鸟尔禾组烃源岩生成的成熟油气进入三叠系底部、侏罗系底部、白垩系底部等碎屑岩不整合储层中聚集,以形成中浅部油/气藏和稠油油藏为主。
There are multiple stratigraphic oil and gas reservoirs in the northwest margin of Junggar Basin, and there are still some disputes in terms of their hydrocarbon accumulation period and time. Therefore, 58 samples of fluid inclusions were collected from 26 wells in this area. Based on the analysis results of burial history and thermal evolution history, the above mentioned fluid inclu- sions were studied in terms of their microscopic characteristics and homogenization temperature characteristics by means of fluid in- clusion microthermometry, and accordingly, hydrocarbon accumulation period of stratigraphic oil and gas reservoirs in this area was determined. And then, the hydrocarbon accumulation process of stratigraphic oil and gas reservoirs were rebuilt by using hydrocar- bon generation and expulsion history of source rocks and structure development history in this area. Based on the analysis, some con- clusions were reached as follows. First, the mature oil and gas generated by Permian Jiamuhe Formation source rocks migrated into Carboniferous volcanic reservoirs and Permian Jiamuhe, Fengeheng and Xiazijie Formations clastic unconformable reservoirs and ac- cumulated during Late Permian - Early Triassic. Second, the mature oil and gas generated by Permian Fengcheng Formation source rocks migrated into Permian and the unconformable glutenite reservoirs at the bottom of Triassic during Late Triassic - Early Juras- sic and middle-deep oil reservoirs were mainly formed. And third, the natural gas generated by Permian Jiamuhe Formation source rocks and the mature oii and gas generated by Permian Lower Wuerhe Formation source rocks migrated into clastic unconformable reservoirs at the bottoms of Triassic, Jurassic and Cretaceous during Late Jurassic - Early Cretaceous, and middle-shallow oil/gas reservoirs and heavy oil reservoirs were dominantly formed.