【作者】 郭艳琴；

【导师】 李文厚；

【作者基本信息】 西北大学 ， 矿物学、岩石学、矿床学， 2006， 博士

【摘要】 本文综合应用层序地层学、沉积学、储层地质学等理论和方法,通过野外剖面观察、钻井岩心观察、测井资料解释、薄片鉴定、扫描电镜和储层岩性物性分析等手段,对富县探区延长组的沉积相及储层微观特征进行了较深入的研究。 论文在富县探区首次应用高分辨率层序地层的观点和方法,把延长组划分为1个超长期、4个长期、9个中期和24个短期4级规模的地层旋回,并与延长组传统的地层划分进行对比。根据古水流方向和轻重矿物分析认为沉积物主要来自东北方向,母岩为北部大青山地区的上太古界乌拉山群和下元古界二道凹群的变质岩。识别出三角洲前缘水下分流河道和三角洲平原分流河道微相是富县探区延长组油气储集的骨架砂体,砂体的发育完全受控于沉积相的展布,均呈北东—南西方向条带状展布。 富县探区延长组砂岩主要为岩屑长石细砂岩和长石细砂岩,杂基含量低,胶结物含量高,主要是方解石、绿泥石膜,其次是水云母、自生石英、长石、网状粘土、高岭石及浊沸石等。成岩作用普遍进入晚成岩A期,主要成岩作用有压实、胶结、交代及溶蚀作用,其中压实、胶结作用是降低砂岩物性的主要成岩作用,溶解作用则有效改善了储层物性。主要成岩相有绿泥石薄膜胶结相、泥质胶结相、石英、长石胶结相、碳酸盐胶结相及浊沸石溶蚀相,其中绿泥石薄膜胶结相和浊沸石溶蚀相发育区物性较好,而碳酸盐胶结相发育区物性差,常为成岩致密带。 残余粒间孔、溶蚀粒间孔、溶蚀粒内孔、溶蚀填隙物内孔隙及自生矿物晶间微孔隙为研究区主要孔隙类型,孔喉结构为:小孔细喉型、小孔微细喉型、小孔微喉型、微细孔微细喉型及微细孔微喉型,为低孔、低渗储层,且具较强的非均质性。总体上长2和长3油层组物性最好,长8、长6油层组次之,长7油层组最差。富县探区各种敏感性均表现为中等以下的敏感性程度,基本不会对生产造成很大的影响,某些地区甚至还出现盐酸酸化后渗透率上升,储层物性得到改善的情况,酸化可作为研究区油气开发生产的有效手段。 富县探区延长组储层物性主要受沉积相、构造背景和成岩作用三大因素控制。沉积相对储层的控制表现为:延长组储层粒度总体较细、长石、岩屑等塑性碎屑颖粒、胶结物含量高,决定了延长组原始物性较差;稳定的克拉通沉积盆地背景决定了构造活动弱、热流值低,导致了延长组储层经过了较长时间和较高强度的压实、胶结作用与较晚的有机质成熟时间、较弱的有机酸溶蚀和裂缝的不发育。这些因素共同决定了研究区延长组储层低孔、低渗的特点。 综合分析富县探区储层孔渗参数,参考前人储层评价研究,将富县探区储层划分为四类,并对各油层组储层的分类和平面展布进行研究。通过找砂体发育带及高孔、高渗带结合产能特征和测井资料在富县探区延长组不同层位优选出11个油气有利区块,为下一步勘探开发提供了地质依据。更多还原

【Abstract】 Applied with outcrop observation, core description, geophysical logging interpretation, thin section determination, Scanning Electron Microscope, reservoir lithology and physical property analysis and other analytic machinery, the sedimentary facies and micro-characteristic of Yanchang Formation in Fuxian exploration area are studied deeply.Viewpoint and method of high resolution sequence stratigraphy are firstly applied in Fuxian exploration area, Yanchang Formation are divided four scale Cycles, such as one Long-long-term Sea Level Cycle , four Long-term Sea Level Cycles, nine Middle-term Sea Level Cycles, and twenty-four Short-term Sea Level Cycles, and are compared with traditional stratum partition. By the studying of the paleocurrent direction and the light and heavy minerals, it make sure that NE is the main direction of sediment provenance, the original rock are Wulashan group in uper Archeozoic and down Proterozoic Erdaowa group in Daqinshan region north of Ordos Basin. Subaqueous distributary channel in delta front microfacies and subaerial distributary channel in delta plain microfacies are identified ,which are the main reservoir sand bodies for oil and gas of Yanchang Formation in Fuxian exploration area, the distribution of sand bodies distributed from northeast to southwest are dominated by sedimentary facies .Feldspar-lithic fine-sandstone and feldspar fine-sandstone are mainly sandstone of Yanchang Formation in Fuxian exploration area, the content of matrix is low and the content of cement is high which are mainly calcite ,chlorite films, in the second place are hydromica , autogeny-quartz , autogeny-feldspar, reticulation clay, Kaolinite and laumontite etc. All the sandstones have entered A period of late diagenetic stage. The dominant diagenesis types in the area are compaction, cementation, replacement and dissolution, in which compaction and cementation are mainly factors to reduce sandstone physical property and dissolution effectively improved physical property. Chlorite films cementation facies, mud cementation facies, feldspar and quartz cementation facies, carbonate cementation facies and laumontite solution facies are the main diagenetic facies . The area with chlorite film cementation facies and laumontite solution facies possess better physical property and with carbonate cementation facies possess bad physical property that forming compact belts.Remnant intergranular porosity , intergranular dissolution porosity, intragrnular dissolution porosity, filling constituents dissolution porosity, authigenic mineral intercrystal porosity are main pore types. Pore texture can be classified as following: small pore and fine throat type, small pore and micro-fine throat type, small pore and tiny throat type, tiny fine pore and micro-fine throat type and tiny fine pore and microthroat type. Yanchang Formation is low-pore and low-permeability reservoir and heterogeneity of sandy reservoir is very serious, as a whole, Chang2 and Chang3 is the best, Chang6 and chang8 is the second and Chang7 is the worst. In Fuxian exploration area, all sorts of reservoir sensitivity are below medium, by which production are not influenced seriously, even permeability become higher after acidification by hydrochloric acid, resulting in physical property improved. Therefore, acidification can be an effective measure of exploitation in this area.Reservoir are mainly influenced by sedimentary facies, tectonics and diagenesis. The control function of sedimentary facies for reservoir shows that sandstone is fine, such plastic grains as feldspar and lithoclast content are high, determining the original physical property of sandstone is not good. The feeble multiphase tectonic activity and low heat flow value are determined by the background of steady craton sedimentary basin , which results the reservoir experienced longer and stronger compaction and cementation, later hydrocarbon maturation, feebler organic acid dissolution and undeveloped fissure. All these facters decide that the characteristic of the reservoir in this area is low- pore and low- permeability.Studying the parameter of pore and permeability comprehensively and consulting prevenient study results of evaluation of reservoir, the reservoir is classified four types and the classification and distribution of reservoir in oii-bearing beds of Yanchang Fonnation are studied respectively.By looking for sand body and higher pore and higher permeability area, combined with oil product characteristic and electromotive curve data, eleven advantageous blocks of oil are predicted of different oibearing beds of Yanchang Fonnation in Fuxian exploration area, which provide the credibility geology gist for further exploration and exploitation in this area.更多还原