Songfangtun structural zone of Xujiaweizi block in Songliao Basin has abundant oil and gas resources,but the source and accumulation process are complex and unclear.By means of organic geochemistry,natural gas geochemistry and fluid inclusions,the hydrocarbon sources and accumulation periods of Denglouku Formation in Songfangtun structural zone are emphatically analyzed,and multi-strata series accumulation pattern is established.The results show that the mudstone of Denglouku Formation Songfangtun structural zone has poor quality,with or-ganic matter of mainly Type Ⅲ and Type Ⅱ2 and Ro of 1.73%in high maturity stage.The mudstone of Shahezi For-mation in Xuxi sub-sag is mainly good-very good source rock,with organic matter type of Type Ⅲ-Ⅱ1 and Ro of 2.55%in over-maturity stage.The oil of Denglouku Formation Songfangtun structural zone is mainly sourced from the mudstone of Denglouku Formation Songfangtun structural zone and the mudstone of Shahezi Formation in Xuxi sub-sag,while the gas of Denglouku Formation Songfangtun structural zone is mainly sourced from the mudstone of Shahezi Formation in Xuxi sub-sag.Hydrocarbon of studied area migrated in 89.6～67.5 Ma,with maximum migra-tion period of approximately 76.0 Ma.Continuous hydrocarbon supply of Denglouku Formation mudstone and Shahe-zi Formation mudstone is material basis for hydrocarbon accumulation in Songfangtun structural zone.Multi-strata series interlayered sandstone-mudstone and main faults and sand bodies transporting oil and gas are necessary con-ditions for accumulation.Highly matching of hydrocarbon generation period and accumulation period is the key to multi-strata series accumulation.Multi-strata series hydrocarbon accumulation pattern formed in Songfangtun struc-tural zone with multi-geological conditions coupling.The research provides theoretical support for oil and gas explo-ration in Songliao Basin.
维普
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