【作者】 郑小杰；

【导师】 赵虹；

【作者基本信息】 长安大学 ， 矿物学、岩石学、矿床学， 2009， 硕士

【摘要】 鄂尔多斯盆地是我国最早发现油田的盆地之一,也是我国第二大含油气盆地,油气资源丰富,主要含油层系为三叠系延长组和侏罗系延安组。侏罗系延安组是陕北斜坡中东部最主要的含油气层系之一,由于侏罗系油藏埋深浅,产量高,经济效益好,成为该地区今后重要的接替层系之一。侏罗系油藏分布特征不仅受到延安组各小层沉积相与砂体展布的约束,更重要的是受三叠系末期古地貌的控制。因此,在沉积体系研究的基础上,选择适当的研究方法精细刻画前侏罗系古地貌尤为重要。本文以陕北斜坡中东部的安塞油田南部为例,应用高分辨率层序地层学基本原理,通过野外露头、岩芯、录井、测井等资料,划分单井层序,并建立该区的层序地层格架,在此格架的约束下,将延安组主要的目的层位延9油层组和延8油层组分别划分为延9₃、延9₂、延9₁以及延8₃、延8₂、延8₁各三个小层。通过野外露头观察,结合前人的研究成果,认为安塞油田早侏罗世富县组的物源主要来自西部、西北部和北部,而中侏罗世延安组的物源主要来自北部及东北部。同时在物源分析的基础上对研究区早中侏罗世沉积体系进行了系统的研究,认为研究区早中侏罗世主要发育河流—三角洲沉积体系,其中富县组发育充填式的洪积或辫状河沉积体系,延安组延10期为辫状河、曲流河沉积体系,延9～延7期主要为三角洲前缘沉积。利用研究区富县期、富县期+延10期地层厚度图、砂体厚度展布图、沉积相及延长组顶部古侵蚀面图等的综合研究手段,对研究区前侏罗纪古地貌进行了详细的刻画,认为研究区古地貌可以划分为古河谷、谷坡、河漫台地及河谷洼地微隆起等几种古地貌单元,并分析了各个古地貌单元的特征。最后针对侏罗系油藏的特点,主要从油源、古地貌、油气运移通道、油藏类型、油气成藏模式以及储集体发育特征等方面探讨了侏罗系油藏的富集规律,结合生产、试油以及老井复查等资料优出选多个有利目标区,并提出下一步油气勘探的方向。更多还原

【Abstract】 The Ordos Basin is one of those where oilfields are discovered at the earliest time, also is the second largest hydrocarbon-bearing basin which contains abundant oil and gas resource in china, the main oil-bearing are Triassic Yan’chang formation and Jurassic Yan’an formation.As one of the most important oil-bearing in the Mid-Eastern of Shanbei slope, Jurassic Yan’an formation has been one of the important successor of oil-bearing formation in this area. Jurassic oil distribution could be not only restricted by Sedimentary facies of Yan’an formation and distribution of the sandbodies,but also the paleogeomorphology on the end of Triassic. Therefore ,on the basis of reseaching of the sedimentary facies,it is very important to intensively characterize the paleogeomorphology of pro-Jurassic that to choise the proper theory of discussion.This article takes the south Ansai oilfield in the Mid-Eastern of the Shanbei slope for example,on the basis of High Resolution Sequence Stratigraphy,combined with the outcrop of field section,cores,logging and other geological materials,further to set up sequence stratum system.By restricted of this system,we divided the main oil-bearing of Yan’an formation Yan9 and Y8 into Yan9₃、Yan9₂、Yan9₁ and Yan8₃、Yan8₂、Yan8₁.Through outcrop observation,combined with previous research results,we hold that Early Jurassic source of Fuxian group is mainly from the western, northwestern and northern, and the provenance of the Middle Jurassic Yan’an Formation is mainly from the northern and north-eastern Department.At the same time ,through the systematic study of early Jurassic sedimentary system in studied area based on the analysis of provenance,we hold that The sedimentary systems were River-delta depositional systems during the Early and Middle Jurassic in this area ,in which Fuxian Group was the filled deposit of alluvial fan-braided or fluvial rifer depositional systems,Yan10 was braided fluvial river-meandering river depositional system,Yan9～Yan7 was delta front depositional system.Using the comprehensive measures of the strata thicknesses chart of Fuxian period and Fuxian+Yan10 period、the sand bodies distribution chart、sedimentary facies and palaeo-eroded landform in the top of Yanchang formation to recoverage of the pre-Jurassic Palaeogeomorphology in detail,we can divid palaeogeomorphology of studied area into incised-valley、valley Slope、overbank platform and Valley-downbend uplife ect, analyze the various Characteristics of paleogeomorphology units.Finally, characteristics for the Jurassic reservoir, we mainly from the source of oils, palaeogeomorphology, hydrocrabon migration pathway, reservoir types, hydrocarbon accumulation patterns and characteristics of reservoir and so on to discuss the hydrocarbon enrichment of Jurassic reservoir, combination of production,production test, and Old Well review and other information to select a number of favorable target areas, and make the next step of oil and gas exploration.更多还原