第7卷第1期 付金华等:鄂尔多斯盆地西南地区上三叠统延长组沉积相及石油地质意义 strata are preserved integration with relatively high intensity of drilling efforts. The subaqueous dis tributary channel is the main type of the fan delta front while the channel mouth bar is developed local- ly. The tur bidite sandstone is mainly thick- bedded. Fan delta front subfacies was best developed during the Chang 8 Subage. Three delta front sandbody belts are formed from southwest to northeast and they are the important areas where hydrocarbon accumulates. The tur bidite system was well developed in the Chang 7 Subage because the lake basin subsided, the periphery was uplifted strongly and the lakeshore was very steep. The fan delta was developed again because the lake regression occurred during the Chang 6 Subage, but the scale was smaller than that of the Chang 8 Subage. The fan delta front sandbody is the most advantageous zone of petroleum accumulation because of its great thickness coarse grainsize, well sorting and good physical properties Key words Ordos Basin, Upper Triassic, sedimentary facies, alluvial fan, fan delta, turbidite About the first a uthor FuJinhua, born in 1963, was graduated from the department of Explo- ration in Jianghan Petroleum Institute. Now he is a senior engineer at the research Institute of Explo- ration and Development of Changqing Oilfield Company, Petro China and is mainly engaged in the geo logical research for petroleum exploration 河三角洲(宋凯等,2002;武富礼等,204),又区别 1前言 于辫状河三角洲(武富礼等,2004)和水下扇 鄂尔多斯盆地是我国典型的克拉通沉积盆地 在经历了早古生代浅海台地和晚古生代的近海湖盆 发育之后,至中生代进入了内陆湖盆的形成发展阶 段,尤其是晚三叠世延长期,是湖盆发展的全盛 期,湖盆底形呈西陡东缓的箕状,在东北、西南两 大物源控制下,形成了以东北河流三角洲、西南扇 银川天 乌审旗 三角洲为代表的两大沉积体系(何义中等,2001;张 伊林西 春生等,2000;魏红红等,2002;宋凯等,2003) 按沉积旋回将延长组自上而下分为10个油层组 靖边 依次为长1到长10(表1),其沉积特征反映了湖盆 形成、发展和消亡的演化全过程。长9、长7、长 志丹a延 4+5亚期是湖盆演化中的三大湖侵期,尤其是长7 亚期,湖侵达到鼎盛期,沉积了盆地中生界最好的 烃源岩。三大湖侵期之间是岸进期,以长8、长6 长3亚期为代表,形成了重要储集层系。盆地东北 平正 及中部广大地区经过多年综合研究和勘探证实,主 要为一套河流相和三角洲相沉积,而盆地西南陇东 100km 地区(图1)延长组,因勘探程度较低而缺少系统的 沉积相研究。本文通过盆地西南缘崆峒山、汭水 研究区[口地名区构造单元界线 河、策底坡等露头,结合区内100余口钻井剖面 图1研究区构造位置图 岩心、测井等资料对延长组特别是长8到长6的沉 Fig. 1 The tectonic location of the st udy area 积相进行了细致的划分,并探讨沉积相的分布演化 特征,指出鄂尔多斯盆地西南地区延长组沉积相以 李克勤,1982,陕甘宁盆地三叠系延长组长1-长10沉积相 扇三角洲为主,既区别于盆地东北沉积体系的曲流内部资料 201994-2007ChinaAcademicJournalElectronicPublishingHouse.Allrightsreservedhttp://www.cnki.netstrata are preserved integration with relatively high intensity of drilling efforts1The subaqueous dis2 tributary channel is the main type of the fan delta front while the channel mouth bar is developed local2 ly1The turbidite sandstone is mainly thick2bedded1Fan delta front subfacies was best developed during the Chang 8 Subage1Three delta front sandbody belts are formed from southwest to northeast and they are the important areas where hydrocarbon accumulates1The turbidite system was well developed in the Chang 7 Subage because the lake basin subsided , the periphery was uplifted strongly and the lakeshore was very steep1The fan delta was developed again because the lake regression occurred during the Chang 6 Subage , but the scale was smaller than that of the Chang 8 Subage1The fan delta front sandbody is the most advantageous zone of petroleum accumulation because of its great thickness , coarse grainsize , well sorting and good physical properties1 Key words Ordos Basin , Upper Triassic , sedimentary facies , alluvial fan , fan delta , turbidite About the f irst author Fu Jinhua , born in 1963 , was graduated from the Department of Explo2 ration in Jianghan Petroleum Institute1Now he is a senior engineer at the Research Institute of Explo2 ration and Development of Changqing Oilfield Company , PetroChina and is mainly engaged in the geo2 logical research for petroleum exploration1 1 前 言 鄂尔多斯盆地是我国典型的克拉通沉积盆地。 在经历了早古生代浅海台地和晚古生代的近海湖盆 发育之后 , 至中生代进入了内陆湖盆的形成发展阶 段 , 尤其是晚三叠世延长期 , 是湖盆发展的全盛 期 , 湖盆底形呈西陡东缓的箕状 , 在东北、西南两 大物源控制下 , 形成了以东北河流三角洲、西南扇 三角洲为代表的两大沉积体系(何义中等 ,2001 ; 张 春生等 , 2000 ; 魏红红等 , 2002 ; 宋凯等 , 2003) 。 按沉积旋回将延长组自上而下分为 10 个油层组 , 依次为长 1 到长 10 (表 1) ,其沉积特征反映了湖盆 形成、发展和消亡的演化全过程。长 9、长 7、长 4 + 5 亚期是湖盆演化中的三大湖侵期 , 尤其是长 7 亚期 , 湖侵达到鼎盛期 , 沉积了盆地中生界最好的 烃源岩。三大湖侵期之间是岸进期 , 以长 8、长 6、 长 3 亚期为代表 , 形成了重要储集层系。盆地东北 及中部广大地区经过多年综合研究和勘探证实 , 主 要为一套河流相和三角洲相沉积 , 而盆地西南陇东 地区(图 1) 延长组 , 因勘探程度较低而缺少系统的 沉积相研究。本文通过盆地西南缘崆峒山、 水 河、策底坡等露头 , 结合区内 100 余口钻井剖面、 岩心、测井等资料对延长组特别是长 8 到长 6 的沉 积相进行了细致的划分 , 并探讨沉积相的分布演化 特征 , 指出鄂尔多斯盆地西南地区延长组沉积相以 扇三角洲为主 , 既区别于盆地东北沉积体系的曲流 河三角洲(宋凯等 ,2002 ; 武富礼等 , 2004) ,又区别 于辫状河三角洲(武富礼等 ,2004) 和水下扇 Ξ 。 图 1 研究区构造位置图 Fig11 The tectonic location of the study area Ξ 李克勤 119821 陕甘宁盆地三叠系延长组长 1 —长 10 沉积相 1 内部资料 第 7 卷 第 1 期 付金华等 : 鄂尔多斯盆地西南地区上三叠统延长组沉积相及石油地质意义 35