准噶尔盆地红山嘴地区三叠系克下组辫状河沉积特征

Braided River Depositional Characteristics of the Triassic Lower Karamay Formation at Hongshanzui,Junggar Basin

为阐明红山嘴地区三叠系克下组沉积相类型与特征,利用岩心、测井录井、粒度等资料,采用岩石学特征分析、岩心特征观察、岩相划分与垂向序列分析等多种手段和方法,对克下组沉积环境和沉积序列进行了深入研究。结果表明:研究区克下组以砾岩、粗砂岩及粉砂质泥岩为主,成熟度低,粒度范围大;识别出8种典型岩相,3类岩相组合;确定克下组为辫状河沉积,发育辫状河道、心滩、漫溢、泛滥平原4种沉积微相;最后,建立了该区克下组受洪流控制的近源间歇性强水动力辫状河沉积模式,为红山嘴地区克下组油气储层的研究提供借鉴。

In order to unravel the sedimentary facies and characteristics of the Triassic Lower Karamay Formation in the Hongshanzui area,we integrated core and well logging,thin section,and grain-size data,and conducted various analyses on the petrological features,core sedimentary structures,lithofacies division,and vertical sequence to study the sedimentary environment and sequence.The results show that the conglomerate,coarse sandstone,and silty mudstone are the main rock types,with low maturity and large grain-size range.Eight typical lithofacies and three lithofacies assemblages were summarized.Braided river sedimentation was recognized in the Lower Karamay Formation,with its microfacies including:braided channel,mid-channel bar,overflow sand,and floodplain.Sedimentary model of the Lower Karamay Formation is featured by being source-proximal,flood-controlled with intermittent strong current.Our new model provides reference for the Lower Karamay Formation reservoir research in the district.