【作者】 朱世全；

【导师】 黄思静；

【作者基本信息】 成都理工大学 ， 矿物学、岩石学、矿床学， 2006， 博士

【摘要】 鄂尔多斯盆地中生界上三叠统延长组是一套以大型内陆盆地为背景、以河流和湖泊相为主的陆源碎屑沉积。根据岩性、电性和古生物特征，延长组划分为五段、10个油层组。 通过对姬塬地区长2油层组大量的岩心观察，取得了丰富的沉积构造和岩性信息，结合测井曲线分析研究，并对收集到的大量薄片鉴定资料、重矿物资料、物性资料进行统计分析，同时对长2(包括小层)地层厚度特征进行研究，我们有如下认识： 姬塬地区长2油层组主要发育平原网状河(网结河)沉积。在长2~3到长2~1的时间段中，砂地比向上降低、砂岩向上变细，河床逐渐变缓、古陆逐渐夷平、沉积物供给逐渐减少，砂体逐渐萎缩，到长2末期，除少数地区以外，研究区已几乎完全沦为网状河沼泽湿地系统。在长2的主要时间段中，姬塬地区主要受北东物源控制，但在长2~2后期和2~1的时间段中，显示出北部偏西物源的掺合作用。 碳酸盐胶结物对储层的影响主要是负面的，高岭石、绿泥石和硅质胶结物都可以从不同的角度对埋藏条件下孔隙的保存起到一定的积极的作用。从成岩作用角度来说，姬塬地区长2油层组储层砂岩孔隙保存与发育的主要机制包括：a)早期分散的胶结作用，主要是石英的胶结作用；b)粘土矿物的早期孔隙衬里，主要是绿泥石的孔隙衬里；c)大气淡水的溶解作用，主要是印支期曝露时间间隔中的大气淡水溶解作用。 印支期曝露时间间隔中大气淡水的溶解作用是姬塬地区长2油层组储层砂岩最为重要的成岩作用，不整合面附近砂岩次生孔隙显著增加。与全盆地相比，姬塬地区长2油层组具有显著较低的粒间孔隙含量和显著较高的次生孔隙含量，储层对成岩作用和次生孔隙的依赖较大。下部小层具有比上部小层更为有利的形成粒间孔隙的沉积条件，而上部小层则具有比下部小层更为有利的形成次生孔隙的成岩条件。姬塬地区长2油层组大致属于Ⅱa类，即中等质量储层类型中的中上等亚类；下部小层的储层质量略好于上部小层。 本论文还利用剥蚀厚度求解新模型对三叠纪末期剥蚀厚度及剥蚀古地貌进行了恢复、解释。 最后，根据各小层沉积相和砂体的分布特征以及成岩作用的研究成果，同时考虑三叠纪末期剥蚀厚度的大小、古河道古沟谷的发育、长2高岭石分布等特点，并依照优先考虑上部油层组砂体的原则，兼顾与有利生油岩分布区的关系和构造部位，参考物性状况，我们建议了6个区块，作为供参考的有利评价区块。更多还原

【Abstract】 The Yan-Chang formation of Upper Triassic in Ordos basin is mostly detritus sediments derived from rivers and lakes sedimentary environment on setting of inland basin. It is divided into 10 subformations containing oil and gas by its lithologic, electric, and paleontological characters.We have obtained abundance of information about its sedimentary structure and lithologic characters by observing bore cores of Chang2 subformation, and combining with the information from well-log curves, and a great deal of thin section observation, heavy mineral analysis, porosity and permeability data, stratum thickness, et al. In the end, we get following achievements:The sedimentary facies of Chang2 subformation in JiYuan district are reticulation fluvial. During the time from Chang2~3- Chang2~1, the ratio for thickness of sand bodies to thickness of stratum decreased, with fine granularity, gentle grade of riverbed, and shrinking sandbodies. The environment of JiYuan district had evolutated into marsh in the terminal of Chang2 subformation. At the most time of Chang2 subformation, the material province of JiYuan district is mainly located in northeast to some degree.The carbonate cementation is mostly negative to development of reservoir, however, kaolinite, chlorite and silica cementation are favored to preservation of reservoir space from many aspects. The mechanism for conservation and evolvement of pore of Chang2 from diagenesis are as following: a) early quartz cementation during diagenesis; b) lining of chlorite in pores in early period; c) dissolution of feldspar by freshwater during the Indosinian period, which is the most important diagenetic mechanism in Chang2 subformation in our target area. Moreover, the secondary pores increased violently near surface of unconformity.The intergranular pores are very low, whereas the secondary pores are very high in JiYuan district compared with the entire basin. During the whole diagenetic stage, the role of the secondary pores are very important for the improvement of reservoir quality.The intergranular relatively pores prevailed in the lower part of Chang2 subformation than the upper part, on the contrary, the upper part contained more sencondary pores than the lower part of Chang2 subformation. the reason leading to更多还原