准噶尔盆地玛湖凹陷二叠系风城组碱性成岩作用浅析

利用岩石薄片、电子探针、扫描电镜和阴极发光等测试技术,分析了准噶尔盆地玛湖凹陷风城组的碱性成岩现象及其形成条件,建立了碱性成岩模式。玛湖凹陷风城组是一套火山岩、碳酸盐岩、碎屑岩、富硅硼钠石岩和泥岩组成的混积岩。岩石中发育白云石环带、石英溶蚀、绿泥石和沸石胶结等碱性成岩现象。分析认为,这种特殊的碱性成岩现象是在特定的原岩、气候条件和成岩事件下形成的。中基性碱性火山岩为碱性成岩作用提供了碱性物质;干旱-湿热交替的气候促进了"碱性湖泊"的形成;埋藏后的水岩反应形成了特定的碱性矿物组合。在此基础上,建立了原岩-气候-水岩反应的多因素影响的碱性成岩模式。这种碱性成岩作用对于玛湖凹陷油气藏的保存具有相当重要的贡献。

Analysis on alkaline diagenesis of the Permian Fengcheng Formationin Mahu Sag,Junggar Basin

Using rock slices,electron probe microanalysis,scanning electron microscope and cathodoluminescence and other testing techniques,the alkaline diagenesis phenomena and formation conditions of the Fengcheng Formation in the Mahu Sag,Junggar Basin are analyzed,and an alkaline diagenesis model is established.The Fengcheng Formation in the Mahu Sag is a peperite comprised of volcanic rock,carbonate rock,clastic rock,rich reedmergnerite rock and mudstone.Dolomite zonal,quartz dissolution,chlorite cementation and zeolite cementation have developed in the rock.Analysis alkaline diagenesis occurs under the conditions of specific original rocks,climate conditions and diagenetic events.Mafic-intermediate alkaline volcanic rocks provide materials for alkaline diagenesis.The alternating of dry-humid hot climate promotes the formation of“alkaline lakes”.After the deposition and burial of the sediments,fluid-rock reaction forms a specific alkaline mineral assemblage.On the basis of it,build a alkaline diagenesis model influenced by multiple factors of original rocks-climate-fluid-rock reaction.This alkaline diagenesis has a very important contribution to the preservation of oil and gas reservoirs in the Mahu Sag.