【作者】 李珊珊；

【导师】 王纪祥； 郭彦如；

【作者基本信息】 中国石油大学 ， 矿产普查与勘探， 2010， 硕士

【摘要】 鄂尔多斯盆地西北部延长组长9-10油层组作为勘探新区,以往对其沉积体系和油气成藏规律等尚未做过深入研究。本文以大量野外露头剖面、钻井、测井、地震及各种化验分析资料为基础,以沉积学、层序地层学、石油地质学、地球物理学等理论为指导,系统研究了盆地西北部长9-10油层组沉积期的高分辨率层序地层格架特征、沉积体系特征、油气成藏条件及规律等,主要取得以下几个方面的进展：将长9、长10油层组划分为2个长期基准面旋回(SQ1-SQ2),5个中期基准面旋回,其中长9、长10油层组分别对应一个长期基准面旋回；并指出该沉积期短-中期基准面旋回主要呈上升不对称叠加样式。研究区在长9-10油层组沉积期主要发育西北、东北、南部-西南部三大物源体系。其中以西北物源体系为主要物源,南部-西南部物源体系为次要物源,随着湖盆的扩张及地层抬升,东北物源体系影响随之减小。研究区在该期主要发育辫状河、辫状河三角洲、曲流河三角洲和滨浅湖四种沉积相,受古气候、古构造背景、基准面旋回变化等因素所控制,主要发育东北部三角洲沉积体系、西部辫状河-辫状河三角洲沉积体系和西南部辫状河三角洲沉积体系,并以辫状河、辫状河三角洲沉积体系为主；沉积体系的发育和演化平面上呈由外向内逐渐变细、垂向上呈自下而上逐渐变深的沉积充填样式。油藏多位于构造高部位,烃源岩分布范围、四级层序界面与沉积相带的匹配控制油气富集。结合研究区成藏因素分析,在盆地西北部延长组长9-10油层组预测了5个主要有利目标区。其中以长91砂层组(SQ2-MC2旋回)、长92砂层组(SQ2-MC1旋回)为主力目标层,长101(SQ1-MC3旋回)为次要目标层。更多还原

【Abstract】 As a new exploration eara, there is no further research on the reservoir-forming rule of oil and gas and the sedimentary system of Chang9-10 oil-bearing formations in the northwest of Ordos Basin. Based on plenty of field outcrops, drilling, logging, seismic and various laboratory analysis data, an investigation about Chang9-10 oil-bearing formations in northwest Ordos Basin on the sedimentay systems and the prediction of favorable targets in the chronostatigraphic sequence framework, under the guidance of Sedimentology, Sequence Stratigraphy, Petroleum Geology and Geophysics, has been finished with several progresses as followed:The research divides the interval Chang9 to Chang10 oil-bearing formations into two long-term base level cycles (SQ1 and SQ2),which in turn are further divided into five medium-term base level cycles, all of which are stacked in base level rise asymmetrical patterns.In Chang9-10 Period, the study area mainly developed three source systems in direction of northwest, northeast and southweat. The northwest one is the primary source system, southwest source system is the minor one, the northeast source system’s impact on this eara decreased because of the expansion of the lake and the uplift of this formation.The types of developed sedimentary facies in this area include braided stream facies, delta deposits facies of braided stream and meandering river, coastal shallow-lake facies. Controlled by papaeoclmate, palaeotectono-geomorphic feature, base level cycling and so no, meandering delta systems in northeast, braided delta systems in southwest, braided stream-braided delta in northwest of this eara have been developed. The evolution of the sedimentary systems presents basin-filling characters of gradually fining from the margin to the center as well as vertically deepening upward.The hydrocarbon accumulation distributes in the high location of structural in this area, which in mainly lithologically ruled, with the fourth-order sequnence boundaries, sedimentary facies and quality reservoirs controlling hydrocarbon enrichment. Based on the study on the depositional systems and hydrocarbon accumulation, the paper finally proposed five favorable targets in this eara. Chang91 (SQ2-MC2 cycle) and Chang92 (SQ2-MC1 cycle) are the main target groups, Chang101 is the minor one.更多还原