鄂尔多斯盆地晚三叠世火山物质对油气成藏条件的影响  

Effect of late triassic volcanic sediment event on hydrocarbon accumulation conditions in Ordos Basin

作　　者：左智峰[1,2] 戚颖[3] 葛小瑞[3] 郭西峰[3] 杨友运[3] 赵俊兴[1] 

机构地区：[1]成都理工大学沉积地质研究院,四川成都610059 [2]中国石油长庆油田分公司勘探部,陕西西安710021 [3]西安石油大学油气资源学院,陕西西安710065

出　　处：《兰州大学学报（自然科学版）》2008年第3期12-15,共4页Journal of Lanzhou University(Natural Sciences)

基　　金：国家重点基础发展研究规划项目(2003CB214607);国家自然科学青年基金(40602012)资助．

摘　　要：从火山物质的沉积地质背景和分布特征入手,通过岩石化学组分分析,系统探讨了火山物质与油气成藏条件之间的关系.认为火山物质主要形成于盆地初始发展和持续拗陷阶段,分布在长7、长6和长4+5油组中,以中酸性安山岩、流纹质熔结凝灰岩和玻屑凝灰岩为主,赋存状态有火山岩碎屑颗粒和沉凝灰岩薄层两种方式.盆内延长组火山物质与东缘铜川组火山喷发凝灰岩具有相同的沉积特点,说明物源来自盆地东部吕梁山方向.成岩中,位于湖盆中心长7油组烃源岩之上大范围沉积的火山物质加速了有效烃源岩的形成,火山物质的易溶和蚀变有利于次生孔隙形成.Analysis of the depositional settings, spatio-temporal distribution, geochemistry and their linkages with the formation and preservation of gas and oil showed that the volcanic beds, including the andesite, liparitic welded tuff and glassy tuff, occurred in the volcanic detrital enclosed within the sandstones or in the thin tuff beds intercalated in the sedimentary layers, in particular in Chang 7, Chang 6 and Chang 4＋5 members and happened during the basin initiation and stable depression, the sedimentary provenance came from the ranges of Luliang Mountain. The magnitude volcanic materials within Chang 7 through Chang 2 in the center of basin acccelerated the formation of the efficient source rock, the secondary porosity and the reservoir heterogeneity because of the dissolvation and alteration of volcanic materials during the diagenesis.

关 键 词：晚三叠世 火山事件 油气成藏条件 鄂尔多斯盆地 

分 类 号：P618[天文地球—矿床学] TE122.1[天文地球—地质学]