【作者】 韩会平；

【导师】 李勇； 王宝清；

【作者基本信息】 长安大学 ， 古生物学与地层学， 2005， 硕士

【摘要】 鄂尔多斯盆地是我国第二大含油气盆地,油气资源非常丰富,油气勘探与开发的潜力很大。它已成为我国未来油气勘探与开发的最重要的战略地区之一,其油气资源的探明与开发直接影响着我国石油的产量。大路沟地区作为鄂尔多斯盆地一个重要的产油区,三叠系延长组长6油层组作为鄂尔多斯盆地大路沟地区的主要含油层系,其油气资源的勘探与开发对长庆油田的发展有很重要的意义。然而,该油层组以低孔、低渗和低压为特点,制约了该区油田的增储上产。为了查明该区油气储层的形成条件和控制因素,预测有利储集带则成为该区迫切需要解决的问题。 本文是在野外观察和室内资料全面分析的基础上,运用沉积学、石油地质理论,借助常规物性、压汞、铸体分析、薄片鉴定、扫描电镜、X光衍射、阴极发光、粒度分析等多项测试手段,对大路沟地区延长组地层进行了划分与对比,并重点研究了延长组主力产油层长6油层组的地层特征,在地层格架内,详细分析和研究了长6油层组含油砂体的岩石学、沉积相与岩相古地理、成岩作用及储集物性特征。结果表明,该区长6沉积时期为三角洲建设的高峰期,发育在志丹三角洲的高速生长期,主要有水下分流河道、支流间湾和河道砂坝等微相;储集砂体为成分成熟度低,结构成熟度高的细粒长石砂岩,少数为岩屑长石砂岩;主要胶结物为绿泥石、浊沸石、方解石和自生石英等,成岩作用主要为压实作用、胶结作用和溶蚀作用等。在此研究基础上,建立了成岩演化模式,认为储层成岩演化阶段处于晚成岩A₂亚期。 研究区储层砂体的储集空间以粒间孔为主,次为粒内溶蚀孔、铸模孔和残余铸模孔。长6砂岩孔喉组合为细小孔微细喉型,孔隙度平均为11.85%,渗透率平均为1.27×10^-3μm²。 研究区储层性质主要受原始陆源碎屑组分、沉积相和成岩作用的控制,构造运动对本区储层性质的影响较有限。绿泥石、浊沸石、碳酸盐、硅质、自生粘土矿物的胶结作用、压实作用和浊沸石、长石的溶解作用也是影响储集性能的主要因素。较有利的储集砂体为水下分流河道砂体。 在综合分析研究的基础上,对大路沟地区延长组长6储层进行了分类评价,并预测了最有利的勘探区带。更多还原

【Abstract】 Ordos basin is the second largest sedimentary basin on land in China which possesses abundant oil and gas resources and has bright prospects in oil and gas exploration. It has been becoming one of the important tactical area in oil and gas exploration in China. The amout of oil and gas resources and the degree which it is proven will directly influence the development of China petroleum Industry.Dalugou oilfield is one important generative area of oil in the Ordos basin.As one primary oil bed in Dalugou area, exploration and exploitation of the sixth reservoir unit of Triassic Yanchang formation are significant.However, the reservoir is characterized with low porosity,low permeability and low pressure that restricts to its output.It is exigent to understand the formation conditions and control factors for petroleum reservoir in order to fine out advantageous regions in the area.On the basis of the geological investigations in the field and analysis indoors, combined with the theories on the sedimentary facies and petroleum geology, by means of various analytical techniques including conventional analysis of the core, analysis of capillary pressure,examination for resin-impregnated thin sections under a microscope, scanning electron microscope, analysis by x-way diffractometer,et al.the paper divide and correlate the Yangchang formation stratigraphic framework in Dalugou area. And stress to study the sixth reservoir unit of Yanchang formation in the sequence framework,discuss the characteristics of petrological,sedimentary facies and lithofacies palaeogeography,diagenesis and reservoir physical property in detail.These studys indicate that sedimentary time of the sixth sandstones of Yanchang formation is the peak period of formation of Zhidan delta in Dalugou area ,the main sedimentary microfacies are submerged distrbutary channel,interdistributay bay,et al; the reservoir rocks are characterized with low compositionally maturity and relatively high textural maturity of fine grained arkose and the least lithic arkose;and its diagenetic mineral includes chlorite,laumonite,calcite,authigenic quartz,et al.The diagenesis mainly includes compaction,pressure solution,cementation,dissolution,et al.Based on the pattern of diagenetic and porosity evolution established,the reserveoir diagenetic stages can be classified into A-substage of later diagenesis.The main reserveoir space of the sixth reservoir unit of Yanchang formation in this area is intergranular pore and intergranular dissolution pore.The sixth reservoir unit of Yanchang formation have small pores and fine throat.The average porosity is 11.85%,and the average permeability is 1.27×10~3μm~2.Reservoir properties are mainly controlled by primary continental detrital composition,sedimentary microfacies and diagenesis;the effect of the tectonic movement on the reservoir is relatively limited.The research shows that the physical property of submerged distributary channel sandbodies is the best.The cementation of chlorite,laumontite,calcite,silicicastic,authigenic clay minerals,as well as thedissolution of laumontite,feldspar are of main factors which affect reservoir properties.The more favorable reservoir sandbodies are submerged distributary channel sandbodies on delta front.At last, the reservoirs are classified and predicted prospecting advantageous regions.更多还原