【作者】 赵虹；

【导师】 李文厚；

【作者基本信息】 西北大学 ， 矿物学、岩石学、矿床学， 2004， 博士

【摘要】 鄂尔多斯盆地是我国重要的能源基地，具有丰富的油气资源。安塞油田位于鄂尔多斯盆地陕北斜坡的中东部偏南处，自20世纪8 O年代初被发现以来，经过20年的勘探与开发，已成为鄂尔多斯盆地一个重要的产油区。中生界三叠系延长组是安塞油田的主要含油层系，油藏类型属隐蔽岩性油气藏，具有典型的低渗、特低渗特点，储层非均质性强，油气分布规律复杂，勘探开发成本高。为了降低勘探开发成本，搞清油气分布规律，为今后的开发提供可靠的地质依据，有必要对延长组进行高分辨率层序地层学研究。 应用高分辨率层序地层学理论与沉积学等理论，通过野外露头观察、岩芯描述、钻测井资料的分析，对安塞油田上三叠统延长组进行了高分辨率层序地层学的划分与对比，首次建立了油田范围内上三叠统延长组高分辨率层序地层格架，并重点研究了延长组主力产油层长6和长2油层组的高分辨率层序地层特征。在层序地层格架内，探讨了储集砂体及沉积微相的发育和展布规律，结合物性、薄片等大量测试分析资料，研究了储层的特征及其非均质性，并对影响储集层性能的因素进行了分析。在综合分析的基础上，总结归纳了安塞油田延长组油气富集规律，并对区内不同级次旋回储层的有利区块进行了预测。主要取得如下认识： 在全盆地三叠系延长组沉积演化分析的基础上，通过古流向及重矿物组合等资料的综合分析，表明研究区延长组主力产油层的物源方向相似，主要来自NE—NEE向。 通过野外典型剖面观察、岩芯描述及大量钻测井资料，系统分析了安塞油田延长组的岩石相、测井相，建立了不同沉积环境的岩-电响应关系。 对研究区延长组各油层组的沉积微相类型、特点进行了详细的研究，认为安塞油田延长组长6和长8油层组主要属三角洲前缘亚相沉积；长2油层组主要为辫状河沉积；长3及长10油层组主要为曲流河沉积，长7、长9及长4+5油层组主要为湖泊沉积。 层序界面研究表明，研究区延长组主要的层序界面有三种，一种为基准面上升到下降的转换面，即湖泛面，主要包括最大湖泛面LF（长7“张家滩”页岩）、次级湖泛面MF₁（长9“李家畔”页岩）和MF₂（长4+5“细脖子”泥岩）；另一种为基准面下降到上升的转换面，主要为冲刷面、岩相突变面等；第三种为岩一电响应明显的泥岩标志层。 以岩芯、测井资料为基础，运用基准面旋回识别原则，将延长组划分为一个长期基准面旋回（LSC）、4个中期基准面旋回（MSC₁-MSC₄）和9个短期基准面旋回（SSC:一SSC，），并在油田范围内进行了追踪对比，首次建立了安塞油田延长组高分辫率层序地层格架，并重点研究了主力产油层SsC，和ssCZ的超短期基准面旋回地层特征. 研究区不同级次基准面旋回的储集砂体及沉积微相研究表明，区内ssC:储集砂体主要为辫状河河道砂坝砂体，而ssC，为三角洲前缘水下分流河道砂体，河口坝砂体和席状砂体较少见.砂体的延伸方向与物源及沉积微相展布方向一致，均呈北东一南西向. 不同的基准面旋回内，储层的物性特征不同.通过研究区SScs及ssCZ岩石成分、结构、孔渗特点、孔隙类型及孔陈结构的研究表明，安塞油田SsC:物性条件明显优于SsCS.影响延长组储层物性的因素主要有沉积环境、砂岩成分与结构、成岩作用、裂陈等. 延长组储层非均质性强，这与基准面旋回及相分异作用关系密切.在基准面上升半旋回内，随着基准面的上升，可容纳空间增大，形成正韵律沉积;而在基准面下降半旋回内，形成反韵律沉积.从而显示出层内与层间的非均质性.由于相的分异作用，‘在不同的地方形成不同的沉积砂体类型，显示出平面非均质性. 综合研究表明，丰富的烃源岩、有利的沉积相带、良好的生储盖组合、理想的上倾遮挡、局部鼻状隆起构造及浊沸石溶孔等是研究区油气富集的主要因素.并以沉积背景、储层特征、成藏条件和勘探程度为依据，开展了有利区块的评价和预测，在ssc，中预测6个有利区块，在sscZ中预测5个有利区块，为研究区下一步深化研究和劫探开发提供了地质依据.更多还原

【Abstract】 The Ordos Basin is one of the most important energy source bases in China. It has abundance oil resource. Ansai Oilfield is located in the slope of Shanbei of the Ordos Basin. Since the oilfield has been found in 1983, after 20 years prospecting and developing, it has become the important oilfield in the Odors Basin. The main oil-bearing layer is Triassic Yanchang Formation. It belongs to the petrology concealment oil-gas and has the characteristics of low permeability or very low permeability. Because the strong heterogeneity of the reservoir and the complexity of oil distribution, the cost of exploration is very high. In order to reducing the cost of the exploration and development, finding out the rule of the oil and gas distribution, providing the credibility geology gist for the further development, it is necessary to research the fine division and correlation of the strata.Based on the high resolution sequence stratigraphy and the sedimentology theory, by the observing of outcrops, the describing of cores and the analyzing of well log data, the paper establish the Yanchang Formation stratigraphic framework in the first time in Ansai Olifield. And stress to study the Chang 6 and Chang 2 oil-bearing formation in the sequence framework, discuss the characteristics of the sandbodies distribution and sedimentary microfacies. Using porosity and permeability data, the heterogeneity of reservoir has been studied and the controlling factors also have been analyzed. On the basis of above synthesis analysis, the author generalize the factors of the oil collecting and its distribution rules, at last the exploration targets have been assessed. By the study, it gains the results as follows:On the basis of analysis sedimentary evolvement history of Upper Triassic Yanchang Formation in the whole basin, by the studying of the paleocurrent direction and the heavy minerals, it make sure that NE~NEE is the main direction of sediment provenance.By the observing of the typical outcrops, the describing of the cores and interpreting lots of the well logs and seismic data, the author discuss the facies of petrology and the facies of log well, and set up the relationship of each other.The type and the characteristics of Sedimentary microfices in Yanchang Formation have been systematic research. The conclusion is that Chang 6 and Chang 8 dominated by meandering fluvial front-delta facies, Chang 2 belong to the braided river deposition, Chang 3 and Chang 10 is meandering fluvial facies, and Chang 7,Chang 9 and Chang 4+5 are lacustrine facies.There are three kinds of the interface. One is the base level changing from ascending to descending- that is the flooding surface. The second is the base level changing from descending to ascending-that is the erosive bottom surface. In addition, the mud and tuff symbol layers thatpossess the clearly characteristic are the good gist in dividing and correlation strata.On the basis of cores and well log data, Yanchang Formation has been divided into one long term base level cycle, four middle term base level cycles, and 9 short term base level cycles. The strata framework of Yanchang Formation in Ansai Oilfield has been established in the first time. And the short base level cycle SSC5 and SSC2 also has been subdivided, and set up the responding super-short term base level cycle framework.The characteristics of the sandbodies and the microfacies of the reservoir in different order base level cycles indicate that the reservoir of SSC2 is the braided sandbodies while the SSC5 is the front delta channel sandbodies. The direction of the sandbodies is consistent with the direction of the sediment provenance and the microfces distribution-that is the NE-NEE.Different base level cycles have different porosity and permeability properties of reservoirs. By the studying of the petrology component and structure, the porosity and permeability, the porosity types and the porosity structure, SSC2 is better than SSC5 in porosity and permeability properties. Its controlling factors are the sedimentary更多还原