鄂尔多斯盆地延长地区延长组储层特征
延长组储层多以Ⅱ、Ⅲ为主，Ⅰ类分布范围较小。
（5）在各沉积微相中，以三角洲前缘水下分流河道砂体的储层性能较好，条带状砂体在垂向上相互叠置，平面上砂体因侧向加积使河道变宽，砂体被泥岩包裹，起到封堵盖层的作用，因此是油气聚集的主要场所。
通过对延长组长6各油层组的储集砂体展布规律进行系统的研究，明确了储层类型的分布情况，是研究区开展工作的出发点和落脚点，为延长组进一步部署石油勘探工作提供了重要的依据。
关键词：延长组，沉积相，成岩作用，储层特征，延长地区
Abstract
The Ordos Basin is located in the central and western part of the Chinese mainland and it is a multi-cycle sedimentary basin that has undergone long-term structural evolution,in general,it is a rectangle with short things and long north and south.As an important petroleum energy source in the Ordos Basin,the Yanchang area has become the focus of attention.The Yanchang Formation is the main oil production layer of many energy companies.It has the characteristics of low porosity and low permeability and has received extensive attention from researchers.At present,the Yanchang Formation has broad prospects for exploration.Due to the fact that many problems in the study area are not fully understood,It is mainly reflected in the research on sedimentary environment,sedimentary facies,diagenesis,reservoir heterogeneity and reservoir characteristics.This paper is directed at the problems that restrict exploration and development,and is guided by theories of sedimentology, stratigraphy,petroleum geology,sedimentary basin analysis,and sedimentary basins of clastic rocks,etc.According to field outcrop observation,core description, sedimentary facies,and sand body shape analysis,based on the analysis of regional structural features and sedimentary environment,combined with logging data,rock thin sections,cast thin sections,scanning electron microscopy and other analytical methods,the petrological and sedimentary characteristics of the Yanchang Formation in the Yanchang area of the Ordos Basin were studied.A comprehensive study was conducted on the characteristics of physical properties,diagenesis and heterogeneity. Based on this,a comprehensive classification evaluation of the Yanchang Formation reservoirs was carried out and the following conclusions were drawn.
(1)In the sedimentary evolution of the Late Triassic Yanchang formation in Ordos Basin,the delta front depositional system is the main sedimentary type in the study area,among which there are many sedimentary microfacies such as underwater distributary channel,distributary bay,estuary dam,mat sand,underwater natural dike and floodplain;
(2)The Yanchang Formation of the Chang6sandstone group,it can be seen
from a large number of lithological identification results that the sandstone composition is complex and diverse as a whole,there are great differences in the interior.The main components are mainly fine feldspathic sandstone,followed by a certain amount of lithic feldspar sandstone;chlorite,turbidite,and calcite are the main types of interstitials.The pore type is dominated by intergranular pores.The diagenesis undergoes a complex evolution process,with compaction,cementation, and dissolution as the main factors,among them,dissolution.The storage performance of the storage group is greatly improved,particle sorting is generally better,roundness is mostly sub-angular-sub-circular,with a low component maturity and high structure maturity;
(3)In Yanchang area,the Yanchang Formation has a strong reservoir heterogeneity,there are differences between layers,layers,planes during sedimentary and diagenetic processes.The main reason for this difference is the heterogeneity of reservoir properties;
(4)In the study of the sedimentary environment,logging analysis, characteristics of sedimentary facies,spatial distribution of sand bodies,type of pore size,diagenesis and physical properties of reservoirs in the reservoir sand bodies of the Yanchang Formation,through quantified reservoir evaluation indicators and actual production data of the oilfield,the types of reservoir sand bodies of the Chang6 reservoir in the Yanchang Formation of the study area are divided into three types:I, II,and III.The reservoirs of type I and II reservoirs are well-defined,and the porosity is above9%,the permeability is greater than0.5×10-3μm2.The sandstone is dense and has poor physical properties.From the plane distribution map,it can be concluded that the Yanchang Formation reservoirs are mostly II and III,and the I distribution range is small;
(5)In each sedimentary microfacies,the reservoir properties of underwater distributary channel sand bodies with delta front are better,and the strip-shaped sand bodies are mutually superposed vertically.The sand body in the plane enlarges the river channel due to lateral accretion,the sand body is wrapped by mudstone and acts as a sealing cap.Therefore it is the main site for oil and gas accumulation.
Through the systematic research on the distribution law of the reservoir sand body in the Yanchang Formation Chang6,it is clear that the distributing of the reservoir type is the starting point and the foothold of the research area,which provides an important basis for the further exploration and deployment of oil in the group.
Key words:Yanchang Formation,sedimentary facies,diagenesis,reservoir characteristics,Yanchang area
目录
第一章绪论 (1)
1.1选题依据、研究意义 (1)
1.2国内外研究现状及进展 (1)
1.3存在的问题 (3)
1.4主要研究思路及研究内容 (3)
1.4.1主要研究思路 (3)
1.4.2主要研究内容 (3)
1.4.3研究方法 (4)
1.5完成的工作量 (4)
1.6主要创新点 (5)
1.7硕士期间主要参与的项目工作 (6)
第二章区域地质特征 (7)
2.1区域构造背景 (7)
2.1.1大地构造背景 (7)
2.1.2区域构造演化 (8)
2.1.3地层划分与对比 (11)
2.2沉积背景 (16)
2.2.1地层特征 (16)
2.2.2沉积演化史 (16)
第三章沉积相特征 (18)
3.1沉积相划分标志 (18)
3.1.1颜色特征 (18)
3.1.2岩石类型特征 (18)
3.2沉积构造 (19)
3.2.1层理构造 (19)
3.2.2同生变形构造 (19)
3.2.3生物成因构造 (20)
3.3测井相分析 (20)
3.4沉积相类型 (21)
3.4.1水下分流河道 (22)
3.4.2分流间湾 (22)
3.4.3席状砂 (22)
3.4.4河口坝 (23)
第四章储层特征 (25)
4.1储层岩石学特征 (25)
4.1.1砂岩的分类 (25)
4.1.2碎屑颗粒矿物成分 (25)
4.2储层物性特征 (27)
4.2.1孔渗物性特征 (27)
4.2.2孔隙度平面分布特征 (29)
4.2.3渗透率平面分布特征 (32)
4.3储层成岩作用 (35)
4.3.1成岩作用类型 (35)
4.3.3成岩阶段划分 (38)
第五章储层非均质性特征 (40)
5.1层内非均质性特征 (40)
5.1.1粒度韵律 (40)
5.1.2层理类型 (41)
5.1.3渗透率韵律 (41)
5.1.4渗透率非均质程度 (42)
5.2层间非均质性特征 (44)
5.2.1分层系数 (44)
5.2.2有效砂岩密度 (45)
5.3平面非均质性特征 (45)
第六章储层综合分类评价 (49)
6.1储层类别的划分 (49)
6.2主要储层展布与分类评价 (49)
6.2.1长61储层展布与分类评价 (49)
6.2.2长62储层展布与分类评价 (50)
6.2.3长63储层展布与分类评价 (51)
6.2.4长64储层展布与分类评价 (53)
结论 (54)
参考文献 (55)
攻读学位期间取得的研究成果 (63)
致谢 (64)