【作者】 吴峧岐；

【导师】 张哨楠；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2008， 硕士

【摘要】 鄂尔多斯盆地是我国第二大盆地,也是同时集煤、石油、天然气三大能源于一体的最大的含能源盆地,也是“西气东输”的骨干资源基地之一。中侏罗系延安组是鄂尔多斯盆地麻黄山地区最主要的含油气层系,其沉积于晚三叠系印支运动之后的盆地稳定沉降期,形成厚度稳定、特征鲜明的河流-三角洲沉积体系。本文的研究目的就是对麻黄山地区延安组的储层特征进行研究,并对储层发育有利区带进行预测。笔者运用了沉积岩石学和石油地质学基本原理,依据钻井和测井资料,结合岩石类型、沉积旋回、沉积构造等多种手段,对延安组地层进行划分和对比;在精细地层对比的基础上,采用岩相和测井相分析相结合的方法认为延安组的沉积体系属于两种类型:河流与三角洲沉积体系。延10为典型的辫状河河道充填型沉积,延9段为广覆型补偿沉积,至延9段古地形被填平,演化为沼泽化平原环境,其中延9～延6主要发育三角洲平原亚相。至延6结束,曲流河沉积开始发育。从古构造格局、沉积构造、结构、碎屑的成分特征诸方面探讨了研究区沉积物的来源:鄂尔多斯盆地麻黄山地区延安组主要存在三大物源,分别在研究区的北部、西部和西南部的隆起区,但是盆地的主要物源区为研究区的西部和盆地的北部。前侏罗系古河道的主流向是从西北流向东南。根据大量的岩芯分析和岩石薄片观察,延10段-延9段主要为长石岩屑砂岩、岩屑长石砂岩,粒度以粗～中粒为主;延8段、延6段、延5段以长石砂岩为主,粒度以细粒为主,中粒次之。粒度自下往上有变细的趋势.砂岩成分成熟度低为主,结构成熟度高为主。研究区主要的成岩作用有有压实作用、压溶作用、胶结作用、溶蚀作用和次生加大作用。溶蚀作用对储层物性起到了建设性作用。研究区延安组岩石孔隙类型较多,主要有原生粒间孔隙、粒内溶孔、铸模孔、溶蚀缝等。延安组地层物性较差,其孔隙度主要为10%～15%,而大部分储层的渗透率都小于10×10^-3μm²。延8段孔隙度平均值14.12%、渗透率平均值80×10^-3μm²,而且K＞10×10^-3μm²的样品超过60%;延9段、延10段孔隙度平均值12%左右,延9段渗透率平均值20.94×10^-3μm²,延10段渗透率平均值仅1.7×10^-3μm²,渗透性最差。因此延8段物性最好,而且其孔隙度、渗透率与孔隙结构参数间有明显的线性关系,应为粒间孔发育的孔隙性储层。通过分析沉积环境对储层控制作用得知,麻黄山地区延安组最有利的储集层为中砂岩,或者说是平行层理中砂岩相,其次为灰白色平行层理粗砂岩相,最差的是平行层理细纱岩相。根据物性、压汞等资料将工区内储集岩分为了Ⅰ:好储层;Ⅱ:中等储层;Ⅲ:差储层;Ⅳ:非储层四种类型。根据这个标准,延8段属于Ⅰ类:好储层;延9和延10段都属于Ⅱ类:中等储层。综合沉积相带和砂体展布、储层储集性能等多方面因素分析,对储层进行了综合评价。最终对储层发育有利的勘探区进行了预测。更多还原

【Abstract】 Ordos basin is the second largest basin in China,and the largest basin containing three energy sources of Petroleum、gas and coal,and one of the backbone resource bases for "West to East Gas Pipeline Project".The Yan’ an formation of Middle Jurassic is the most important Oil&Gas-bearing series in Mahuangshan area of Ordos basin.Which was formed after the steady sedimentation period of late Triassic indo-China movement,the fluvial-delta sedimentary system with steady thickness and distinct characteristics was formed.The aim of this thesis is to research on reservoir characteristics of Yan’ an formation in Mahuangshan area,and to forecast where favorable reservoir zones developed.By applying of basic principles of sedimentary petrology and petroleum geology,based on well drilling、well logging data,combined with the ways of the rock types、sedimentary cycle、depositional texture,etc.The Yan’ an formation strata was divived and correlated.Based on the subtly stratigraphic correlation,by ways of combination of litho-facies and logging facies,the sedimentary systems of Yan’ an formation had two types:the fluvial system and the delta system.The Yan 10^thwas typical braided river channels-filling type deposition,before the paleo-landform was deplanated and evolved into paludification plain environment in Yan 9^th.Yan 9^th～Yan 6^thwere delta plain facies,till the end of Yan 6^th,meandering river deposition began developing.From paleo-structure pattern、depositional structure and texture、composition characteristics of debris etc.Sediment source of the study area was discussed,which indicated that there were three sediment sources,and the debris material of Yan’ an formation in Mahuangshan area of Ordos basin came from the north、the west and the southwest margin uplift area,but the sediment mainly came from the north and the west.The mainstream direction of paleo-river channel in pre-Jurassic was from northwest to southeast.By analyzing a large quantity of rock cores and observing a large mount of rock thin sections,we found the lithology of Yan^10-9is feldspathic lithic sandstone、debris feldspar sandstone with particle size mainly coarse to medium,and the lithology of Yan⁸、yan⁶、Yan⁵ is mainly arkose with particle size mainly fine,medium particle being in the second place.From lower to upper,The particle size gets finer.The compositional maturity of sandstone is mainly low while the textural maturity is mainly high.The primary diageneses of the research area were compaction、pressure solution、cementation、dissolution and secondary enlargement.And the dissolution had made constructive impact on the physical properties of the reservoir.There were many kinds of pore types in the research area,such as primary inter-granular pore、intra-granular dissolved pore、mould pore and dissolution fracture etc.The physical properties of Yan’ an formation were poor,the porosity was mainly 10%～15%while the permeability of most reservoirs were below 10×10^-3μm².The average value of porosity in Yan⁸ was 14.12%while the average value of permeability was 80×10^-3μm²,and the proportion of samples with permeability more than 10×10^-3μm² exceeded 60%.The average values of porosity in Yan⁹ and Yan¹⁰both were about 12%,the average value of permeability of Yan⁹ was 20.94×10^-3μm² while in Yan¹⁰it was just 1.7×10^-3μm²,poorest among Yan⁸～Yan¹⁰.So the physical properties of Yan⁸ were best among Yan⁸～Yan¹⁰,and there were apparent linear relationships between porosity,permeability and pore structure parameters,it should be a layer of porous reservoir in which inter-granular pores developed.By analyzing the sedimentary setting’ control over reservoir,it indicated that the most favorable reservoir of Mahuangshan area was medium sandstone,or say parallel bedding medium sandstone facies.Gray-white parallel bedding coarse sandstone facies was in the second place while parallel bedding fine sandstone facies being poorest.According to physical properties、mercury injection data etc,the reservoir of the study area could be classified into four types as follow:Ⅰ:Good quality reservoir;Ⅱ:Medium quality reservoir;Ⅲ:Poor quality reservoir;andⅣ:Non-reservoir. According to this classification standard,the Yan⁸ was considered asⅠ:Good quality reservoir while Yan⁹ and Yan¹⁰both were considered to beⅡ:Medium quality reservoir.By comprehensive analyses of multi-factors like sedimentary facies zone and sandstone body distribution and reservoir properties etc.Reservoir was evaluated. Finally,the forecast of the favorable reservoir prospecting zones of Yan’ an formation was made.更多还原