【作者】 庞军刚；

【导师】 李文厚；

【作者基本信息】 西北大学 ， 油气田地质与开发， 2010， 博士

【摘要】 鄂尔多斯盆地为为中国重要的能源盆地,石油、天然气、煤、铀、水等多种能源同盆共生。延长组为典型的低渗透储层,三角洲砂体发育的东部地区一直是油气勘探的重要区域。本文选取东部研究程度较低的史家畔地区作为研究区,运用沉积学、层序地层学、储层地质学、石油地质学等理论,在大量钻测井、野外露头及测试分析的基础上,对地层、沉积相、沉积模式、储层特征、储层非均质性、成藏模式等方面进行了系统全面的研究,可以丰富陆相低渗透储层研究理论及指导油田勘探。1.根据研究区延长组层序界面的物质表现,如不整合界面、冲刷侵蚀面、最大湖泛面、区域性的洪泛事件标志、岩性—岩相转换面、对比标志层,把延长组划分为一个二级层序,其最大湖泛面(凝缩层)为长7中下部的张家滩页岩,又可进一步划分出5个三级层序,每个层序的平均年限为5.2 Ma,每个三级层序均有低位体系域、水进体系域及高位体系域组成,并和岩性地层划分进行了对比。2.沉积相分析表明,主要发育三角洲、湖泊沉积体系,并进行了亚相和微相的划分,主要受北东相物源影响,三角洲主体为北东或南北向展布,在古地理演化过程中,长10为三角洲平原亚相；长9-长7为三角洲前缘亚相；长64、长63、长62、长61、长4+52、长4+51、长3、长2发育三角洲平原；长1期由于差异沉降作用,湖盆转移至子长附近,研究区为三角洲前缘亚相。并建立了该区浅水三角洲沉积模式。3.储层主要为灰色、浅灰绿色长石砂岩,部分岩屑长石砂岩,粒度以细砂为主,其次为粉砂和中砂。杂基以云母和泥质为主,胶结物主要有石英质、长石质、方解石,少量的白云石、黄铁矿。分选好,磨圆度以次棱角状—次圆状为主,呈颗粒支撑,颗粒间以线接触为主,胶结类型以孔隙式和加大—孔隙式为主。4.储层在成岩过程中经历了不同程度的压实作用、胶结作用、交代作用及溶蚀作用。压实及胶结作用不利于孔隙的保存,而交代及溶蚀作用在一定程度上改善了储层。根据粘土矿物成分、石英加大、孔隙类型等参数分析,储层已进入晚成岩作用A亚期,长6已进入晚成岩A—-B期。划分出弱压实-绿泥石胶结相、弱压实-碳酸盐胶结相、弱压实-石英、长石胶结相、压实-压溶相、弱压实-溶蚀相、浊沸石-长石溶蚀相。其中弱压实-绿泥石胶结相、长石溶蚀相是研究区最有利的成岩相。储层整体为中孔、中低渗,非均质性强,平面上高孔、渗区和分流河道(水下分流河道)区具有良好的对应关系。储层的物性及非均质性受沉积及成岩作用的影响。有利的相带为分流河道及水下分流河道,方解石、云母均与孔隙度、渗透率呈负相关性,而绿泥石薄膜的存在有利于孔隙的保存,可提高储层的物性。根据影响储层物性的主要参数对研究区储层进行了分类,分析其在纵横向上的变化。研究区发育Ⅱ类、Ⅲ类和Ⅳ类等3大类储层,其中Ⅲ类(可分为Ⅲa.Ⅲb)是研究区的主要储层。5.根据孔隙与成岩演化的定量计算公式,对研究区长4+5、长6砂岩的原始孔隙度、压实后粒间体积、胶结后粒间体积、溶蚀后体积及压实率、胶结率、微孔率、溶解孔隙率等进行了恢复,建立了研究区不同成岩作用与孔隙度的定量演化关系。6.通过油藏控制因素和油气富集规律分析,认为研究区延长组具有较有利的生储盖组合和良好的油气圈闭条件。根据有利储层发育,结合产能特征和顶面高程,在研究区延长组不同层位进行了有利区块预测,指出了下一步的勘探重点区。更多还原

【Abstract】 Ordos Basin is an important energy basin of china,and oil, gas, coal, uranium, water and other energy symbiose in the basin.Yanchang formation is a typical reservoir of low permeability. The eastern region in which delta sand body is well-developed has been an important area for oil and gas exploration. Less studied,ShiJiapan region in eastern region was choosed,as our study area,Under the guidance of advanced theories and methods such as sedimentology,sequence stratigraphy,reservoir geology,petroleum geology and so on, on the basis of a large number of logging and drilling, outcrop and testing,stratum,sedimentary facies,sedimental model, reservoir characteristic, reservoir inhomogeneity, play accumulation model and so on,are studied comprehensive, which can enrich the study of continental low-permeability reservoir theory and guidance the oil exploration.1.According to physical manifestations of sequence boundaries in Yanchang formation in study area,such as unconformity surface,scour erosion surface,maximum flooding surface,regional flood event marker,lithology-lithofacies conversion surface, symbol layor of strata comparison, Yanchang formation can be divided into a second-order sequence,in which the maximum flooding surface (condensed layer) is the ZhangJiatan shale on the bottom of Chang 7,and can be further divided into five third-order sequences.The average life span of each sequence is 5.2 Ma,and each third-order sequence is composed of LST,TST,HST and are compared with lithology stratigraphic division.2.Sedimentary facies analysis indicates that the major developed delta, lacustrine, and carry out sub-facies and micro-facies, the main source of the North East with the impact of the North East or the delta of the main north-south distribution, during the palaeogeographic evolution, Chang 10 is delta plain; Chang 9-Chang 7 is delta front; Chang 64, Chang 63, Chang 62, Chang 61, Chang 4+52, Chang 4+51, Chang 3, Chang 2 are delta plain; because of differential subsidence during Chang 1, basin migrated to Zichang area, the vicinity of the study area is delta front sub-facies, and the shallow water delta depositional model was established in study are.3 Reservoirs are mainly gray, light gray green feldspathic sandstone, lithic feldspathic sandstone partly, mainly fine sand and secondly silt and medium sand with respect to grain size. Mica and mud mixed is the main matrix, the quality of cement are mainly quartz, feldspar, calcite, a small amount of dolomite, pyrite.Better selected.sub-angular to sub- rounded with respect to psephicity. Granular supported type and line contact between Granular, pore type and overgrowth are main cement type.4.In the process of diagenesis, reservoir experienced various degrees of compaction, cementation, replacement and dissolution.In which compaction and cementation is harmful to the preservation of pore, while replacement and dissolution improved to some extent the reservoir. According to clay minerals, quartz overgrowth, pore type and other parameters, the reservoir has entered to the stage A,and Chang 6 to stage A-B of late diagenesis. Weak compaction-chlorite cementation, weak compaction-carbonate cementation, weak compaction-quartz and feldspar cementation, compaction-pressure solution facies, weak compaction-dissolution facies, laumontite-feldspar dissolution facies. In which weak compaction-chlorite cementation, dissolution of feldsparfacies arefavorable diagenetic facies. As a whole,Reservoir is belong to low porosity, Medium-low permeability with strong heterogeneity. In plane, there is a good relationship for high porosity and high permeability zones with distributary channel (subaqueous distributary channel) area. Properties and heterogeneity of reservoir are controlled both by sedimentation and diagenesis. Distributary channel and subaqueous distributary channel are favorable micro-facies; There is negatively correlated for calcite and mica with porosity and permeability;while the presence of chlorite film is beneficial to the preservation of porosity and can increase the reservoir properties. According to parameters influencing reservoir properties, the reservoir is classified, and reservoir changes in vertical and horizontal are analyzed.Ⅱ,ⅢandⅣtype reservoirs are all developed,in which type III (can be divided intoⅢa,Ⅲb) is the main reservoir of the study area.5. According to the quantitative formula of porosity and diagenetic evolution, the original sandstone porosity, intergranular volume after compaction, intergranular volume after cementation, volume after dissolution, and such rates as compaction, cementation, micro-pore, dissolution pore are resumed of Chang 4+5 and Chang 6..In the end, quantitative evolutionary relationships between different diagenesis and porosity are established in the study area.6.The analysis result of reservoir control factors and accumulation of oil and gas, shows that Yanchang formation in study area has favorable combination of source bed,reservoir and seal,and good conditions for oil and gas traps. According to favorable reservoir development, combined with deliverability features and the top surface elevation of the study area, favorable blocks are predicted,and main exploration.targets in the near future in different layers更多还原