鄂尔多斯盆地西南缘延长组存在差异构造运动的地质意义

Differential tectonic movement of Yanchang Formation in southwestern margin of Ordos Basin and its geologic significance

鄂尔多斯盆地西南缘环县—镇原地区是近几年的重点勘探地区,随着勘探实物工作量的加大,出现的一些地质现象成为人们关注的焦点。文中根据长7—长6段存在的凝灰岩、震积岩、含灰砾岩和长7—长1段地层加厚等多种资料的综合研究,认为长7—长6段沉积期与长9—长8段沉积期区域构造背景存在明显差异,这种不均衡造成了该区不同层系、不同区块地层层序、沉积环境、岩石学特征的差异,进而影响了含油性。为此该文提出了分区分层、不同油藏类型区别勘探的思路。

Huanxian-Zhenyuan area is one of the major exploration areas in southwestern margin of Ordos Basin in recent years.Some newgeology phenomenons appeared and were cared in the exploration.Based on the analysis of tuff,seismites and limestone gravel in Chang 7 to Chang 6 reservoir and thicken layers in Chang 7 to Chang 1 reservoir,it is believed that areal tectonic setting during Chang 7 to Chang 6 depositional stage is different from that during Chang 9 to Chang 8 depositional stage,which results in different formations,different sequence,different sedimentary settings,different lithologies and different reservoir properties.Different exploration methods are proposed for different layers and different reservoirs.