【作者】 张娜；

【导师】 任战利；

【作者基本信息】 西北大学 ， 地球探测与信息技术， 2007， 硕士

【摘要】 鄂尔多斯盆地是一个多旋回叠合型盆地，油气资源非常丰富，油气勘探与开发的潜力很大。姬塬油田是鄂尔多斯盆地陕北定边地区的一个主要产油区，延安组延9和延长组长2油层组为研究区的两个主要含油层系，为了进一步地研究该区油气聚集的规律，有必要对延9及长2油层组油藏特征做细致的研究。本文以沉积学、石油地质学和测井学理论为指导，在收集大量地质、钻井、测井、试油等资料的基础上，将地质、地球物理、地球化学方法相结合，野外地质调查与室内地质研究相结合，采用多种测试方法及分析手段，对姬塬油区延9与长2油层组地层、构造、沉积、储层及油藏特征进行了深入研究，在此基础上总结了油气富集规律及控制因素。姬塬油区构造总体上为西倾单斜的构造背景上发育鼻隆构造。延9、长2沉积微相类型划分为河道砂坝、决口扇、天然堤、洪泛平原、分流河道、河间洼地等。延安组延9属河流相沉积环境，发育了北东向、近南北向河道砂体；延长组长2属于三角洲平原分流河道沉积，发育了北东向、北北东向、北北西向和近南北向展布的分流河道砂体。综合岩心分析数据和测井解释结果表明延9储层主要为一套中孔—低渗储层，个别低孔一特低渗，以Ⅱ类储层为主。长2储层物性较差，主要是特低孔—特低渗、低孔—特低渗和中孔—特低渗储层，个别中孔—低渗，以Ⅲ类储层为主，个别是Ⅱ类储层。研究区储层物性的好坏主要受沉积微相的控制。河道和分流河道水动力强，颗粒较粗，分选好，胶结物少，储层物性较好。其砂体的主体部位具有较高的孔隙度和渗透率，是油气聚集的有利地带，而向其边缘地带水动力减弱，颗粒变细，孔隙度和渗透率相应变小。河道间及分流河道间以粉砂质泥岩和泥岩为主，是油气聚集良好的侧向遮挡，一般不发育油层。同时成岩作用对储层物性的影响既有破坏性，也有建设性。破坏性作用主要是早期的机械压实、压溶与胶结充填作用；建设性的成岩作用主要是埋藏环境下成岩晚期的溶蚀作用，产生了大量的溶蚀孔，改善了储集条件。姬塬油区油气成藏条件研究表明长7烃源岩为主力生油岩，延长组主要以渗透性砂体作为油气运移通道，油藏主要分布在生烃中心及周边地区；三叠系顶部不整合面和侏罗系古河道砂体共同构成了延安组油气的主要运移通道，其油气主要分布在侏罗系古河道内及其不整合面附近。延安组延9油藏主要受前侏罗纪古地貌控制，圈闭条件主要是压实构造和岩性遮挡，河流相砂体是油气储集空间；延长组长2油层组由于差异压实作用易形成压实构造，在砂体发育带形成鼻状隆起和局部隆起构造，上倾方向若配上岩性遮挡，可形成构造—岩性油藏，分流河道相是油气富集有利区。更多还原

【Abstract】 Ordos Basin is a polycyclic superposition basin which possesses abundant oil & gas resources and has bright prospects in oil & gas exploration. Jiyuan oilfield is one important generative area of oil of Dingbian area in Ordos basin. Yanan formation’s Yan9 and Yanchang formation’s Chang2 oil beds are two primary oil beds in it .For the sake of deeply researching and the rules of hydrocarbon accumulation and distribution, it is necessary to study characteristic of oil storage in the Yan9 and Chang2 oil beds.The theories of sedimentology and petroleum geology and borehole geophysics as direction, on the basis of collecting the data of geology, drilling, logging, oil testing, combining with geology, geophysics, geochemistry, combining with geology investigations in the field and research indoors, using many testing methods and analytical techniques, Yan9 and Chang2 oil beds of Jiyuan oilfield were deeply studied in strata, structure、sediment、reservoir characteristics and characteristic of oil storage.On the basis of these methods, the paper researched the rules of accumulation and the distribution of oil and gas and controlling factors of it.West monocline as background, nosing structures were developed in Jiyuan oil field. Sedimentary microfacies of Yan9 and Chang2 oil beds were river channel sand bar、crevasse splay、natural levee、flood plain, distributary channel, low-lying land between river channel and so on. Yan9 reservoir developed meandering river sediment and sand bodies’ configuration presented a band shape of north-east and nearly south-north trend. Chang2 reservoir developed distributary channel deposit of delta plain and sand bodies’ configuration presented a band shape of north-east, north-north- east, north- north- west and nearly south-north trend.The paper synthesized a lot of the data of core analysis and result of log interpretation . Yan9 reservoir was moderate porosity-low permeability in the majority, low porosity-ultra low permeability individually. The kind of Yan9 reservoir was II type . Chang2 was worse than Yan9 in physical property of reservoir, Main porosity and permeability types of which were ultra low porosity-ultra low permeability, low porosity-ultra low permeability, moderate porosity- ultra low permeability .some was moderate porosity-low permeability. The reservoir types were mainly as III type, some was II type of Chang2.The physical property of reservoir was determined by sedimentary microfacies in researching field. Because the hydrodynamic pressure of Fluvial channel and distributary channel were very strong and the size of grain was large, well gradation, as well as less cementing material, the physical property was well. The main part of sand body which was vantage ground for the hydrocarbon accumulation often had higher porosity and permeability. But the characteristic of the boundary of sand body was opposite to it. The lithology of interchannel and interdistributary area were mainly silty mudstone and mudstone, it was the good lateral barrier and oil usually didn’t accumulate in there. The diagenesis had both constructive and destructive effect to the physical property of reservoir.. The destructive effect was mechanical compaction or pressolution and cemented fill in the early period. The constructive effect was denudation in late diagenesis in the environment of burial and developed a lot of emposieu which improved the physical property of reservoir.The researching of the condition of oil accumulation indicated Chang7 was the main oil source rock in the Jiyuan oilfield. Permeable sandstone was the main petroleum migration pathway of Yangchang Formation, and oil reservoir distributed chiefly at hydrocarbon generation center or regions around it. Surface of Triassic unconform ity and ancient stream channel sandbody of Jurassic constituted the major migration pathway of Yanan Formation, the oil reservoir accumulated primarily in the ancient stream channel and places near the surface of unconform ity.Yan9 oil reservoir was dominated by Jurassic palaeogeomorphology. The traps were mainly compacted structure and stratigraphy barrier. Fluvial facies accumulated oil.Chang2 oil reservoir usually developed compacted structure because of differential compaction and had nosing structure and arched structure in well developeing sand body, where would developed structural-lithologic reservoir if having stratigraphy barrier in the updip direction. Distributary channel facies was in favor of accumulating oil.更多还原