【作者】 仲维苹；

【导师】 操应长； 隋风贵；

【作者基本信息】 中国石油大学 ， 地质学， 2010， 硕士

【摘要】 车排子地区在构造区划上属于准噶尔盆地西部隆起的次一级构造低凸起,形成于晚海西早期,这一时期为泛古陆开始拼合时期,是车排子地区基底岩系形成和车排子凸起的形成阶段。沙湾组沉积时期,车排子凸起总体为一个南倾的斜坡,地形坡度缓、水体较浅,断层不发育。勘探成果表明,车排子地区沙湾组具有良好的勘探潜力,但缺乏录井、测井资料,导致地层格架、物源体系、砂体成因等方面不明确,严重制约油气勘探的深入。本文以地震资料为基础,综合运用地震、测井、钻井、分析化验等资料,对研究区沙湾组层序地层格架、物源方向、砂体成因和空间展布等进行系统性的研究,取得了以下成果和认识:(1)根据层序地层学理论和方法,建立了车排子地区新近系沙湾组精细层序地层格架。车排子地区新近系沙湾组从下到上可划分出沙一段、沙二段2个四级层序,同时,根据全区对比分析,将沙湾组一段内部又划分八个砂层组,并分析了层序地层的空间展布特征。(2)综合古地貌分析、砂砾岩百分含量展布分析、地层(纹层)倾角分析、岩屑组分分析等方法对车排子地区沙湾组物源方向进行研究,结果表明,该区沙湾组存在两大物源体系,分别为西北、北部和东北部物源体系,早期的西北、北部物源体系控制着砂体呈近南北向展布,以缓坡型扇三角洲相为主,晚期的物源方向往东迁移,以东北方向为主,控制着砂体呈东北-西南向展布,以浅水辫状河三角洲和滨浅湖滩坝相为主。(3)沙湾组沉积时期主要发育了缓坡型扇三角洲、浅水辫状河三角洲、冲积扇、滨浅湖滩坝等4种沉积相类型。缓坡型扇三角洲是介于正常扇三角洲和辫状河三角洲之间的一种沉积类型,其沉积颗粒比正常扇三角洲稍细,平原辫状河更发育;浅水辫状河三角洲与正常辫状河三角洲存在一定的区别,前者不存在Gilbert型三角洲模式的顶积层、前积层、底积层三层结构,前积结构不发育,倾斜平缓;骨架砂体为水下分流河道砂体;河口坝沉积不甚发育;垂向沉积层序不连续;席状砂广泛分布。更多还原

【Abstract】 Chepaizi area belongs to the sub-structural unit of the uplift in the west of Junggar basin, and it was formed in early Hercynian, when the pangea began to merge and the basement rock series of Chepaizi area and Chepaizi Salient was forming. In the Shawan Formation sedimentary period, Chepaizi Salient was generally a southward inclineded slope, which had slow slope gradient, low water and no fault developed. The exploratory survey showed that the shallow layer of Shawan Formation in Chepaizi area had a satisfactory oil-bearing potential but was constrained by the lack of drilling fluid and well logging data. Based on the seismic data and the integrate studying of the cores and the logging data,analysis assay data, the sequence framework of this area, the source direction and the genesis and the distribution of the sand body were studied systematically. The result and conclusion are obtained as follow:(1) According to the sequence dividing principle, the sequence framework of Neogene Shawan Formation in Chepaizi area was established. The Neogene Shawan Formation can be divided into two forth-order sequences followed as the first members of Shawan Formation, the second members of Shawan Formation, and according to the strata correlation of the study area, first members of Shawan Formation can be divided into eight sand sets, of which the spatial distribution was analyzed.(2) With several methods, such as analysis of dip log、sandy conglomerate distribution、analysis of paleo-geomorphic、detritus component, the provenance and palaeocurrent direction of Neogene Shawan Formation at Chepaizi salient in Junggar basin are analysed. The results shows that, there were two sediment origins in this area, one from the north and northwest, and the other from the northeast. In the early sedimentation period, the north and northwest provenance controlled the sand body nearly south-north distribution, and there developed predominantly gentle slope fan delta, while in the late sedimentation period, the provenance direction shifted eastward and became mainly northeast, so the sand body showed southwest-northeast distribution, and there developed predominantly shallow braided river delta and shore-shallow lake. (3) During the sedimentation period of Shawan Formation, there developed four types of sedimentary facies as gentle slope fan delta, shallow braided river delta, alluvial fan, coastal shallow-lake. Gentle slope fan delta is a sedimentary type between fan delta and braided river delta, its sedimentary particles is slightly finer than the normal fan delta, and it develops more braided river on the plain. Shallow braided river delta is more or less different from normal braided river delta, the former one does not exist Gilbert delta mode foreset bed, topset bed and bottomset bed. The shallow braided river delta develops no foreset bed, has slow slope gradient, its main sand body is underwater distributary channel, the river mouth bar is not well developed, the vertical sedimentary sequence is discontinuous and the sheet sand is widely spreaded.更多还原