【作者】 葛鹏莉；

【导师】 张哨楠；

【作者基本信息】 成都理工大学 ， 油气田开发地质， 2010， 硕士

【摘要】 鄂尔多斯盆地为位于华北地台西部的克拉通叠合盆地,是我国最重要的含油气盆地之一,富县地区位于鄂尔多斯盆地南部,基本构造形态为一向北西倾向的单斜。过去十多年经历了几个年度的勘探实践表明,本区从中生界至下古生界已发现多套含油气层系,延长组是其中勘探目的层之一,通过沉积体系的展布、储层特征、有效储层的分布等方面的研究表明富县地区延长组为一个低孔低渗、平面和垂向上非均质性较强的岩性油藏。本论文通过岩心观察、薄片鉴定、物性资料、扫描电镜等的分析统计,结合测井、录井资料及前人的研究成果,利用沉积岩石学、储层沉积学、地球物理测井等学科的理论与方法,系统研究了富县地区延长组储层特征、控制储层的发育因素并对储层进行综合评价。研究表明本区延长组的主力产油层为长8段～长2段,长8段以三角洲前缘砂体沉积为主,长7段、长6段湖盆面积缩小,三角洲前缘亚相与浊积扇沉积发育;长4+5段湖盆面积继续缩小,为三角洲平原发育早期;长3段、长2段湖盆逐渐消亡,发育三角洲平原沉积。通过对该区的岩石学特征、孔隙类型、孔隙结构及四性关系进行研究后认为:延长组砂岩储层的岩石类型主要为细粒长石砂岩、岩屑长石砂岩,具有较低的成分成熟度与结构成熟度,平均孔隙度为9.3%,平均渗透率为0.46×10-3μm2,总体表现为低孔、低渗、微细孔喉且分选较差的特点,剩余粒间孔隙是该储层的主要储集空间,其次为溶蚀孔隙。通过薄片观察与物性分析发现,建设性成岩作用包括溶蚀作用、破裂作用、绿泥石环边的胶结作用抑制石英的次生加大,对储层孔隙有支撑和保护的作用,而导致储层物性变差的破坏性成岩作用主要为压实作用、碳酸盐胶结作用,伊利石等粘土矿物的胶结作用,另外,砂岩粒度、砂体沉积厚度及沉积微相的平面展布也控制着储层的发育,分流河道微相沉积的储层物性较好,其次为河口坝、远砂坝。综合研究表明富县地区延长组砂岩储层的孔隙度下限为8%,渗透率下限0.1×10-3μm2,参考长庆油田对低孔低渗储层的分类标准将延长组储层划分为Ⅰ类、Ⅱ类、Ⅲ类、Ⅳ类、Ⅴ类(非储层),研究区长8段～长2段主要发育Ⅲ类、Ⅳ类储层,其中只有长3段、长2段发育少量储集物性较好的Ⅱ类储层。根据各小层的有效储层厚度与储集系数的平面展布,结合研究区的沉积相分布、油层富集规律,对本区进行储层综合评价,并在目前取得的勘探成果和认识的基础上对长8段、长6段及长3段有利勘探区域进行了预测。更多还原

【Abstract】 Ordos basin, located at the western part of North China platform, is a large-scale superimposed Craton basin and a significant oil-bearing basin in China. Fuxian oil field is on the northwest trend monocline background, it is located in the south of Ordos basin.Over the past ten-years experience of exploration, Fuxian area has been found servial oil-bearing layers from mesozoic to lower Paleozoic. Yanchang formation is one of the most important exploration target layer.And it’s a lithologic reservoir with low-porosity and low-permeability characteristics.Study on the distribution of sedimentary system, reservoir characteristics and effective reservoirs shows that reservoir heterogeneity in Yanchang formation behaves strongly on planar and vertical in Fuxian area.Applied with cores observation, thin section identification, pore texture analysis, SEM analysis and the studied results of former geologists, this thesis deals with the reservoir features, the factors which controlled reservoir characteristics and the reservoir evaluation. Many theories and technological related to sedimentology, reservoir sedimentology, petrology geophysical well-logging have been used. Results indicate that Chang8~2 Members are the main productive layers. Chang-8 Member developed delta front deposition. Delta front and turbidite fan developed in the Chang-7~6 period when the lake basin shrinked. Chang-4+5 Member developed early delta plain deposition and the lake basin was still shrinking. As for Chang-3~2 period, the lake basin was gradually dying out, and delta plain developed.Through the research of petrologic feature, pore types, pore structure and the relationships among lithology, poroperm characteristics, electric properties and oil-bearing properties, it is thought that the lithology of Yanchang formation is mainly fine grained feldspathic sandstone and lithic arkose sandstone, which brings about the feature of low compositional maturity and low textural maturity. Average porosity of the reservoir in Fuxian area is 9.3%, average permeability is 0.46×10-3μm2.It indicate that the reservoirs characteristics are totally of low porosity and permeability, fine pore throat and poor sorting. Remaining primary pore is the dominating pore type in this area, secondly for corrosion pore. By thin section identification and physical property analysis, it’s found that dissolution, cataclasis, cementation of chlorite rims curbed quartz overgrow and protected lots of primary pores. But compaction, carbonate cementation, clay minerals cementation such as illite are the destructive diagenesis which resulted in reservoir properties getting worse. Moreover, the grain size of sandstone, the sedimentary thickness of reservoir and the distribution of sedimentary microfacies are also the controlling factors of reservoir development. By sedimentary analysis, distributary channels deposition enjoys better physical properties than mouth-bar and distal-bar.Above the comprehensive Research, it can be concluded that the low limit of porosity is 8% and the low limit of permeability is 0.1×10-3μm2. Reference to the standard of reservoir evaluation in changqing Oilfield, the reservoirs of Yanchang formation in Fuxian area are classified as five types:Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ(non-reservoir). Type-Ⅲand type-Ⅳreservoir can be seen through the Yanchang formation from Chang-8~2 Member, type-Ⅱonly exists a few in Chang-3~2 Member. Based on the research of effective reservoir, storage factor distribution and combined with sedimentary facies, oil-gas distribution, the result of exploration, the thesis discussed the reservoir comprehensive evaluation and the available exploration block prediction of Chang-8, Chang-6, Chang-3 Member at last.更多还原