【作者】 赵筱艳；

【导师】 任战利；

【作者基本信息】 西北大学 ， 固体地球物理， 2009， 硕士

【摘要】 鄂尔多斯盆地是我国第二大盆地,侏罗系延安组是盆地主要的含油气层系,其沉积于晚三叠系印支运动之后的盆地稳定沉降期,形成厚度稳定、特征鲜明的河流一三角洲沉积体系。义正一吴堡区在构造上位于鄂尔多斯盆地陕北斜坡带的中部,侏罗系的含油层位主要为延安组延10-8层段。本文的研究目的就是对义正-吴堡区延安组的储层特征进行研究,进而指出控制油气成藏的主要因素。在精细地层对比基础上,结合岩石类型及其特征、沉积结构和构造、古生物和测井等相标志,认为延安组的沉积体系有河流、三角洲两种沉积体系,延10为典型的辫状河河道充填型沉积,延9-延7为三角洲平原沉积。研究区河流主要来自东北部、西部,最终由东南流出研究区。根据大量的岩芯和岩石薄片资料,延安组储层岩性主要为中粒长石岩屑质石英砂岩,粒度自下往上逐渐变细。研究区主要的成岩作用有压实作用、压溶作用、胶结作用、溶蚀作用等,本区成岩作用已达晚成岩A期。研究区延安组岩石孔隙类型主要有原生粒间孔隙、溶蚀孔隙,二者占到总面孔率的81.9%。储层孔隙度平均为14.6%,渗透率平均为31.34×10^-3μm²,储层砂岩孔喉组合类型以中孔中、细喉型为主。延10段由于碎屑粒度较大,物性最好,延7物性最差。平面上高孔、高渗区与河道砂体展布有良好的对应关系,储层物性、非均质性受沉积及成岩作用的影响。在综合物性、薄片资料、沉积相带和砂体展布等资料的基础上,根据牟泽辉2001年提出的储层分类标准,对研究区储层进行了综合评价,认为延7主要是Ⅲ类储层（差储层）;延8～延10主要是Ⅱ类储层（中等储层）。通过对研究区储层、沉积相、盖层封闭能力等的综合分析,认为控制本区油气成藏的因素主要有:长7深湖一半深湖相泥岩为延安组油气成藏提供了油源保证;前侏罗纪深切河谷是油气运移成藏的主要通道;沉积相奠定了油气成藏的有利区带;上覆泥质盖层及泥质岩的侧向遮挡是控制油气成藏的必要条件;鼻隆和差异压实构造是油气富集的场所。更多还原

【Abstract】 Ordos Basin is the second largest basin in China,Yan’an formation of Middle Jurassic in Ordos Basin is a major oil and gas department,Which was formed in the steady sedimentation period after the Late Triassic Indo-Chinese Movement,with the thickness of the formation of stable,distinct characteristics of a river delta system.Yizheng-Wubu area locates in the middle of Shanbei Slope Belt in Ordos Basin and the oil-bearing layers of Jurassic are mainly member 10-8 of Yan’an formation.The purpose of this paper is to study the reservoir characteristic of Yan’an formation in Yizheng-Wubu area,and then pointed out the main factors controlling hydrocarbon accumulation.Based on the fine stratigraphic correlation,combined with the rock types and their characteristics,structure and sedimentary structures,paleontology and well logging,the sedimentary systems of Yan’an formation had fluvial system and the delta system.The Yah 10 was typical braided river channels-filling type deposition,Yan 9～Yan 7 were delta plain facies.The river of research area mainly came from the west and the northeast,finally, outflow from the research area.According to a large number of rock cores and rock flakes,we think that the reservoir lithology of Yan’an formation mainly were medium-grained feldspathic lithic quartz sandstone with the particle size getting finer from lower to upper.The main diagenesis of the study area were compaction,pressure solution,cementation,dissolution and so on,the reservoir diagenesis of the research area had reached late diagenesis A period.The study area of Yan’an main types of rock porosity were primary intergranular porosity and dissolution porosity,which accounted 81.9%Of areal porosity.The average values of reservoir porosity was 14.6%,and the average value of reservoir permeability was 31.34×10^-3μm²,the composition type of pore throat mainly were middle hole middle throat-small throat.Because of bigger granularity,the physical of Yan10 were best among Yan10～Yan7,and the physical property of Yan 7 was worst.The high porosity -high permeability zone have a good reltionship with distribution pattern of sandstone in plane, the sedimentary and diagenesis affected the physical properties and unhomogenenity of the reservoir.Based on the physical properties,sheets information,sedimentary facies zone, sandstone body distribution etc,according to the classification standard,which was proposed in 2001 by mou zehui,a comprehensive evaluation of the reservoir has been made:Reservoir of Yan7 mainly belongs to typeⅢ（that is poor quality reservoir）;while reservoir Yan8-Yan10 mostly belong to typeⅡ（that are medium quality reservoir）.Synthetizing the reservoir quality,trap types,the sedimentary facies,the sealing ability of cap rock,etc.factors of controlling accumulation as follows:The deep～semi-deep lake mudstone of chang7 formation provided the high quality source rock for the oil accumulate ion,pre-Jurassic deep down-cutting river offered the migration pathway;the sedimentary facies decided the favorable oil reservoirs zone;the upper mud cap rock and side block of mudstone were essential to the accumulation;matching of nosing and difference compaction structure were the enrichment regulation.更多还原