Hydrocarbon Accumulation Conditions of the Lower Assemblage in Sikeshu Sag, the Southern Margin of Junggar Basin

准噶尔盆地南缘四棵树凹陷下部成藏组合为白垩系吐谷鲁群及以下地层构成的多个储盖组合。该区发育3套烃源岩，资源量大，工作程度低。储集层发育较好，侏罗纪齐古组及白垩纪清水河组为优质储层。圈闭以构造类型为主，面积较大。断裂切割了烃源层及储层，侏罗—白垩系的不整合面为油气运聚的良好通道。油气成藏匹配关系较好。区域盖层分布广、厚度大，具良好勘探前景。凹陷中部褶皱带为油气勘探突破区，北东挠褶带为油气勘探评价区，山前断褶带及下盘隐伏构造带为油气勘探接替区。The lower assemblage refers to several reservoir-cap assemblages consisted of Tugulu Group of Lower Cre-taceous and strata below in Sikeshu sag,the southern margin of Junggar basin.Three sets of source rocks develop in these regions where stores abundant resources but is low degree exploration.The well-developed reservoirs here has high quali-ty,such as the upper Jurassic Qigu Formation and the lower Cretaceous Qingshuihe Formation.Traps are mainly large structural ones.Faults connecting source rocks with reservoirs and unconformity between Jurassic and Cretaceous pro-vide good passages of hydrocarbon migration.In addition, huge thick cap-rocks mostly cover this region.In a word,the time and space of hydrocarbon accumulation generally match with each other.And this region has favorable exploration prospect.The depression of the central fold belt is exploration breakthrough area of oil and gas.North east flexure belt is the oil and gas exploration evaluation area. And the piedmont fault fold belt and the footwall of concealed structure belt are successions of oil and gas exploration.国家科技重大专项中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)2269-2743