柴达木盆地北缘马仙地区路乐河组风成砂岩识别及沉积相模式  

Identification of eolian sandstone in the Lulehe Formation of Maxian area,Qaidam Basin,and its sedimentary model

作　　者：殷建国 郭晖 吴志雄 史基安 琚宜文 张明峰 YIN Jian-guo;GUO Hui;WU Zhi-xiong;SHI Ji-an;JU Yi-wen;ZHANG Ming-feng(Key Laboratory of Cumputational GeoJynaniics,College of Earth and Planetary Sciences,Ufiiversity of Chinese Academy of Sciences,Beijing 1000A9,China;Key Laboratory of Petroleum Resources,Gansu Province/Northwest Institute of EcuEnvirotnnent and Resources,Chinese Academy of Scietices,Lanzhou 730000,China;Research Institute of Exploration and Development,PetroChina Qinghai Oilfield Compatiy,Dunhuang 736202,China)

机构地区：[1]中国科学院大学地球与行星科学学院/中国科学院计算地球动力学重点实验室,北京100049 [2]中国科学院西北生态环境资源研究院/甘肃省油气资源研究重点实验室,甘肃兰州730000 [3]中国石油青海油田分公司勘探开发研究院,甘肃敦煌736202

出　　处：《天然气地球科学》2020年第6期786-799,共14页Natural Gas Geoscience

基　　金：国家自然科学基金项目(编号:41530315,41872160,41804080);国家科技重大专项(编号:2016ZX05066);甘肃省自然科学基金(编号:17JR5RA293)联合资助。

摘　　要：基于岩心、岩石薄片、扫描电镜、粒度、X-射线衍射、孔渗和X-荧光7类数据,从岩性、沉积结构、矿物组分、主量元素和物性条件5个角度对比分析,证明柴达木盆地北缘马仙地区马西5井、马西6井、仙东1井和仙东2井路乐河组取心属于风成砂岩,首次揭示柴达木盆地路乐河组存在风成砂岩。这些风成砂岩为胶结疏松的棕黄色中细砂岩。与水成沉积相比,风成砂岩具有岩性单一、砂层厚、成分成熟度高、石英颗粒磨圆度好且具有风成砂的表面结构,以及粒度近似现代风成砂等方面的特征。在石英-钾长石-斜长石三元图、A-CN-K三元图、PCA分析和MFW三元图4类图解中,风成砂岩与水成砂岩沉积区别明显。另外,通过沉积和物源分析,认为风成砂岩是冲积扇-冲积平原沉积经由风营力的再次搬运、分选和再沉积过程就地形成,并发育于冲积扇-冲积平原的过渡地带,这一沉积模式在柴北缘地区具有较为广泛的适用性,能更好地应用于油气勘探开发涉及的沉积和储层研究。Based on data from cores,rock slices,scanning electron microscope,granularity,X-ray diffraction,porosity and permeability,and X-ray fluorescence,this paper makes a comparative analysis of lithology,sedimentary textures,mineral composition,major elements and permeability,and then proves that the cores of Lulehe Formation from Wells of Maxi 5,Maxi 6,Xiandong 1 and Xiandong 2 in Maxian area belongs to aeolian sandstones,existence of which is the first time to be revealed in the Lulehe Formation of the Qaidam Basin.These aeolian sandstones are brown yellow medium-fine sandstones with loose cementation.Compared with the water-laid sedimentation,the aeolian sandstones have the characteristics of single lithology,thick sand layer,high compositional maturity,good roundness of quartz particles with surface textures of aeolian sand,and the particle size similar to modern aeolian sand.The aeolian sandstone is obviously distinguished from water-laid sedimentation in Zircon-kK-feldspar-plagioclase,A-CN-K ternary diagram,PCA analysis and MFW ternary diagram.In addition,according to the analysis of sedimentation and provenance,it is considered that aeolian sandstones are deposited in the transitional zone of the alluvial fan and alluvial plain,the sediments of which experience the process of re-transportation,sorting and re-deposition of wind.The sedimentary model can be widely applied to support the sedimentary and reservoir research during the process of petroleum exploration and development in the northern margin of Qaidam Basin.

关 键 词：风成砂岩 粒度参数 碎屑锆石U-Pb定年 马仙地区 路乐河组 

分 类 号：TE121.3[石油与天然气工程—油气勘探]