【作者】 刘正华；

【导师】 杨香华；

【作者基本信息】 中国地质大学 ， 古生物地层学， 2007， 硕士

【摘要】 储层地质学是油气勘探开发的一项重要工程。在油气的勘探开发过程中，需要了解储层的层位、成因类型、岩石学特征、沉积环境、构造作用及影响、物性、孔隙结构特征、含油性、储层岩体几何形态、分布规律，以及有利储层分布区域的预测。随着油气勘探开发实践的不断深入，储层地质学研究受到人们的普遍重视，从而得到迅速发展。歧南斜坡带—埕宁隆起区位于南大港构造带以南，是大港地区地层岩性油气藏勘探的重点地区。研究区北部的歧南凹陷是—长期发育的生烃凹陷，凹陷内下第三系地层分别向西、东、南三个方向抬起，依次形成西部缓坡带、东部张巨河构造带、南部羊二庄断阶带，其中西部缓坡带在近两年的地层岩性油气藏勘探中取得很好的勘探成果，南部羊二庄断阶带的友谊油田、东部张巨河构造带的张东油田也是大港油田主要产油区块，其主要含油层系为下第三系沙一段、沙三段。前人对歧南凹陷地区第三系沉积体系、储层发育控制因素，以及岩性地层油气藏形成条件进行了系统分析。根据以往的认识，该区沙一段、沙三段沉积主要受古构造背景控制，发育滩坝及近岸水下扇沉积，如南部羊二庄断阶带的友谊油田的主力储层即为近岸水下扇砂体。随着友谊油田等勘探开发的不断深入，人们越来越清晰地认识到该区储层横向变化快，分油组的沉积微相及储层研究欠缺，有利储层预测难度大。如凹陷区所钻探的歧南2、6、7、8等井均见到较好的油气显示，但均因物性较差未获得成功。现今困扰歧南地区油气田勘探开发的难点问题是寻找优质储集性能的砂体。因此，目前当务之急是进行沉积储层评价、沉积微相划分，明确储层的控制因素，建立符合研究区实际地质特点的储层地质模型，明确砂体展布规律与有利的水道砂体发育相带，为研究区的油气勘探与开发工作提供可靠的地质依据。本文结合歧南凹陷的沉积相研究为基础，充分运用岩心观察、测井、地质录井等第一批资料，利用三维地震技术对水道砂体进行了追踪，利用现代实验室分析技术对研究区沙河街组含油层系进行了储层综合研究。研究中从储层岩石学特征方面入手，详细分析了沙河街组砂岩的孔隙组构和储集性能，探讨了原始矿物组分、成岩作用等对储层质量的控制，阐明了不同水道砂体的储集性能的差别，及其影响因素；结合次生孔隙的分布规律和地震属性反演技术，划分了有利储层的分布区带。地震属性水道砂体追踪表明，研究区水道砂体发育，形态特征典型，内部结构清晰，为多个透镜状砂体叠置的侧积复合体。歧南斜坡为地质背景有利于形成断块—岩性圈闭与上倾尖灭岩性圈闭，勘探潜力大。沉积环境分析表明，沙河街组沉积时期，研究区位于张巨河与羊三木古潜山构造带之间的低洼部位，沉积坡度大，羊二庄断裂、赵北等同沉积断裂活动强度大，为重力流沉积提供了有利的古地理背景。使沙一上底部与沙一中的地层中发育较好的重力流水道砂体。成岩作用研究表明，水道砂体主要位于晚期成岩A期，有利于次生孔隙的发育，其成岩反应序列为：长石淋滤(?)粘土膜(?)泥晶方解石胶结(?)石英加大(?)灰岩岩屑与长石溶解、高岭石充填(?)亮晶方解石、绿泥石、铁方解石、铁白云石沉淀。储集性能差异性分析表明，储层物性受到以下因素的影响：原始储集条件是影响储层物性的重要因素；储层沉积作用对砂体具有平面控制作用；成岩作用对储层物性纵向上有改善作用，主要表现在长石、碳酸盐岩屑等颗粒的溶解有利于形成次生孔隙；钙质胶结、石英加大边、高岭石沉淀降低孔隙度与渗透率。而且研究发现本区砂岩中碳酸盐岩屑含量较高，但是碳酸盐岩岩屑对砂岩成岩—孔隙演化有很大的影响，岩屑呈圆状—次圆状，岩石变形不明显，溶蚀现象普遍，有利于次生孔隙发育。针对歧南凹陷地区沙河街组的沉积成岩特点，结合储层物性发育特点建立了四种成岩—孔隙演化模式。①湖岸滩坝型，砂岩分选、侧向连通性好，原始孔隙发育，孔隙流体活动强，溶蚀现象普遍，次生孔隙发育；②重力流主水道型，侧向连通性好，原始孔隙较发育，孔隙流体主要顺砂体走向活动，碳酸盐岩屑溶蚀现象较普遍，次生孔隙较发育；③重力流水道侧翼、末梢型，砂体侧向连通性不好，原始孔隙较发育，孔隙流体活动弱，碳酸盐岩胶结与高岭石沉淀普遍，交代现象普遍，次生孔隙不发育，储层性能不好；④水下扇间湾型，基质含量较高，孔隙连通性差，机械压实明显，孔隙流体活动较弱，次生孔隙不发育。通过以上研究，认识到重力流水道砂体是本区有利的勘探开发目标。重力流主水道砂体和水道侧翼、水道末梢砂体储层性能的差异。从而也解释了早期勘探的歧南2、6、7、8井储层物性较差的原因。提出对重力流水道砂体进行勘探部署时，应选择主水道中心部位进行钻探。更多还原

【Abstract】 Reservoir geology is a major project in the petroleum exploration.It requires understanding reservoir horizon,geognosy character,sedimentary environment, tectonism and its effect,origin type,reservoir properties,pore structure, oilness,rock body geometry, distribution regulation,and distribution and prediction about advantageous reservoirs.With the petroleum exploration development,reservoir geology is more progressional, and more significant.Qinan ramp region-Chengning uplift,locates in the South part of Dagang tectonic belt,is the stress area of lithostratigraphy reservoirs.The north of the ramp region is Qinan depression,which is a long-term growing hydrocarbon depression. Tertiary stratum uplifts and forms ramp belt in the west,Zhang Juhe tectonic belt in the east, and Yang Erzhuang fault belt in the south.The western ramp belt reveals well exploration success in lithostratigraphy reservoir of recent two years,and YouYi oil field discovering in the southern Yang Erzhuang fault belt and ZhangDong oil field discovering in the eastern Zhang Juhe Tectonic belt,became major product region,the main hydrocarbon reservoir assemblage includes Esl segment and Es3 segment in Tertiary.Predecessors have analyzed sedimentary system in Tertiary, factors controlling reservoir development,and generation condition of lithostratigraDhy reservoirs. The previous research indicates that the Esl segment and Es3 segment stratum develops bank and dam deposition,and offshore underwater fan sediment in the control of palaeotectonics background,like as the major reservoir of YouYi oil field in the south of Yang Erzhuang fault belt belonging to offshore underwater fan sandbody.With the exploration development of YouYi oil field,people recognize that rapid variation of reservoir lateral change in the region and scarcity of sedimentary facies research causes to the difficulty of advantageous reservoi prospect.Because the exploration well such as Qinan2,Qinan6,Qinan7,QinanS,shows good oil and gas,and reservoir property is low.Recently the most important task is looking for advantageous sandbody,so sediment reservoir appraisal, sediment microfacies subdivide,research about factors controlling reservoir attribute,summarization about reservoir geology pattern,sandbody distribution regulation,and advantageous reservoir prospect,will became the geology base of oil and gas exploration.This paper bases on the sediment facies research in Qinan depression,utilizes rock core observation,logging,and geologic control datum,and then uses 3D seismic to pursuit channel sandbody,in the end comprehensive research reservoir of Esl segment with modern laboratory analysis technique.In the aspect of reservoir lithology,this paper analyzes the pore organization and reservoir property in Sha Hejie formation,discusses the control of original mineral composition and diagenesis, and then indicates the distinction and effect of differential channel sandbody reservoir property,combine secondary pore distribution regulation and seismic inversion technique,divide advantageous reservoir distribution.Seismic attribute channel sandbody pursuit reveals that channel sandbody develop well,with typical morphological characteristic and clear internal structure,it is multisystem composed by multi-lenticular sandbodys.The background of Qinan depression make for fault block-lithologic reservoirs trap and updip pinchout reservoirs lithologic trap,exploration potential is great.Analysis of deposition environment indicate that in the Sha Hejie formation, research region locates lowland area between Zhang Juhe and Yang Erzhuang tectonic belt,the steep depositional gradient,intensely synsedimentary faulting movement including Yang Erzhuang faults and Zhaobei faults,offer beneficial palaeogeographic background for gravity flow channel.In the bottom of up-Esl and mid-Esl gravity flow channel group well.Through Diagenesis research,the paper indicates that channel sandbody is in A stage of late-diagenesis,it benefits the secondary pore development,and the sequence of diagenesis includes feldspar leacheate(?)clay membrane(?)micrite calcite cement(?)quartz overgrowth(?)dissolution of limestone debris and feldspar,kaolinite fill(?)deposition of par calcite,chlorite,ferrocalcite and ankerite deposition.Differential analysis of reservoir property shows the property of reservoir is effected by below factors:In the diagenesis,dissolution of limestone debris and feldspar is the major factors accelerating secondary pore development;calcite cementation,quartz overgrowth,kaolinite deposit is main factors decreasing secondary pore,and calcite cementation is much obvious.In the sediment,matrixes fill is the main factors declining low pore,low permeability.Though dissolution of limestone debris is the major origin of calcite cementation,limestone debris is not the direct factors effecting pore development because of its intensive anti-pressure property. From the sediment diagenesis feature in Sha Hejie formation,composing reservoir attribute characteristic,the paper summarize four pore evolution patterns.①Lakeshore bank and bar type,includes the characteristics:good separation and sideways connectedness of sandbody,much development original pores, general denudation,more secondary pores,good reservoir property;②main gravity flow channel type,includes the characteristics:good sideways connectedness of sandbody,much development original pores,general denudation,more secondary pores;③flank distal sandbody of gravity flow channel type,includes the characteristics:bad sideways connectedness of sandbody,much development original pores,weak pore fluid movement,general carbonatite cementation and kaolinite deposition,universally metasomatism,bad secondary pores;④underwater fan inter-bay type,includes the characteristics:high content of matrix,weak pore connectedness,intensive compaction,weak pore fluid movement,bad secondary pores.Base on the above research,the paper draw the conclusion: gravity flow channel sandbody is the major exploration region.Reservoir property of main gravity flow channel and flank distal sandbody of gravity flow channel is distinctive.It interprets why the reservoir attribute of Qinan2,Qinan6,QinanT,and Qinan8 is weak in the early exploration.The paper emphasize that the center part of the main gravity-flow channel sandbody is potential targets.更多还原