鄂尔多斯盆地南梁地区延长组长6沉积特征  

Sedimentary characteristics of Chang 6 in Nanliang area,Ordos Basin

作　　者：马海勇[1] 王为林 沈志成 闫占冬 刘海洋 MA Haiyong;WANG Weiin;SHEN Zhicheng;YAN Zhandong;LIU Haiyang(College of Geology and Environment,Xi’an University of Science and Technology,Xi’an 710054,China;Seventh Oil Production Plant,Changqing Oilfield Company,Xi’an 710018,China)

机构地区：[1]西安科技大学地质与环境学院,陕西西安710054 [2]长庆油田分公司第七采油厂,陕西西安710018

出　　处：《西安科技大学学报》2024年第3期512-520,共9页Journal of Xi’an University of Science and Technology

基　　金：国家自然科学基金项目(41502107);陕西省自然科学研究计划项目(2018JM4033)。

摘　　要：为了研究南梁地区延长组重力流沉积特征,利用钻井岩芯、轻重矿物和测井解释等对鄂尔多斯盆地南梁地区三叠系延长组长6沉积体系特征与沉积模式进行分析。结果表明:鄂尔多斯盆地长6以K2、K3、K4这3套泥岩作为标志层,根据测井分析方法将延长组长6划分为3个小层;依据轻、重矿物数据资料分析,明确了南梁地区延长组长6发育有东北、西南2个物源,主要受东北物源的控制,东北部母源来自于大青山、阴山一带的太古界高级变质岩和火山岩;南梁地区延长组长6主要以陆源湖泊、三角洲沉积为主,不同的沉积相的类型控制着砂体的展布形状,长6期发育的砂体自北东向西南方向呈现出条带状展布;延长组在长6期湖盆面积逐渐减小盆地边缘的三角洲沉积范围向湖盆中心收缩。长6期自北东向西南发育了三角洲前缘亚相、深湖亚相、浅湖亚相,由于三角洲前缘斜坡地带沉积物发生了滑塌,在重力作用下形成了浊流沉积。In order to study the sedimentary characteristics of Yanchang Formation in Nanliang area,the sedimentary system and sedimentary model of Triassic Chang 6 in Nanliang area of Ordos Basin are explored from the data of drilling core observation,analysis of light and heavy minerals and well logging interpretation.The results show that K2,K3 and K4 sets of mudstones are used as marker layers in the Chang 6 reservoir of the Triassic Ordos Basin,and the reservoir is divided into three small layers according to the analysis method of sedimentary cycle characteristics revealed by logging.The analysis of light and heavy minerals confirms that the provenance of the Chang 6 subsection in Nanliang area is predominantly controlled by a northeast provenance,with its primary source derived from highgrade metamorphic rocks and volcanic rocks of Archean age in the Daqingshan and Yinshan areas.The sedimentary facies within the Chang 6 subsection area are primarily influenced by delta deposits originating from this northeast provenance.Consequently,the sand bodies developed during the Chang 6 period exhibit a banded distribution extending from northeast to southwest.It is concluded that the area of the Lake Basin Yanchang Formation in Ordos Basin decreased gradually during the Chang 6 depositional period,with a contraction of the delta sedimentary range towards the center of the basin.The development of delta front subfacies,deep lake sub,and shallow lake subfacies occurred northeast to southwest during the Chang 6 period.Turbidity current deposits are formed in response to water flow and gravity due to sediment collapse in the slope area of the delta front.

关 键 词：鄂尔多斯盆地 南梁地区 延长组 长6 沉积特征 

分 类 号：P512.2[天文地球—地质学]