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1.
珠江口盆地西部珠三坳陷近年来一直未获得商业性油气的重大发现,古近系是坳陷内主要的勘探层系,但对其自下而上的物源体系、沉积充填演化规律认识不清。在层序地层划分基础上,以古近系沉积时期三级层序为基本单元,结合区域地质背景、古地貌、周缘水体分布、重矿物组合及岩石薄片等资料,并利用构造地质学、沉积学等分析方法,开展了珠三坳陷古近系沉积时期的物源体系演化及其对大型碎屑岩储集体分布的控制影响研究。认为珠三坳陷古近系存在两大物源区,一是南部神狐隆起,其母岩构成以岩浆岩、浅变质岩及前古近系沉积岩为主;二是北部海南隆起、粤桂隆起及相关河流体系组成的综合物源区,母岩构成以岩浆岩为主。确定了始新统文昌组断陷沉积时期,主要形成了湖泊-(扇)三角洲体系的构造沉积充填格局,且沉积了巨厚的文昌组中深湖相烃源岩,为本区的主力烃源岩;下渐新统恩平组—上渐新统珠海组断拗沉积时期,主要沉积充填了恩平组湖泊-(扇)三角洲体系以及珠海组滨海潮坪-(扇)三角洲体系。以上研究成果为珠江口盆地西部珠三坳陷下一步寻找优质大型储集体并获得油气发现具有一定的指导意义。  相似文献   

2.
研究区位于珠江口盆地惠州凹陷西南部,毗邻西江凹陷,属于NEE走向和NE走向两组构造体系的转换部位。该地区古近系主要发育近EW走向、NW走向和NE走向的3组断裂,剖面上总体呈平直和铲状两种形态。3组断裂共同控制了研究区古近系不同时期的断陷结构特征。断层活动性和构造沉降分析表明,文昌组沉积期研究区东部北倾断层和西部南倾断层活动强烈,沉降量和沉降速率均较大;恩平组沉积期,受南海扩张影响,总体呈现南倾断层,即向海倾断层活动明显增强,沉降量和沉降速率显著增大的特点;至珠海组沉积期断层活动总体较弱。构造格局及其演化明显控制沉积物充填。快速生长断层因两盘差异沉降显著,其下降盘往往地层厚度大,以发育扇三角洲沉积体系为特征;慢速生长断层下降盘的地层厚度相对较薄,以发育沿断层转换带延伸的辫状河三角洲沉积体系为主。研究区古近纪的构造演化并非简单继承,而是重大转换(T80面是重要的构造变革面),且这种转换是被动大陆边缘近端带对南海扩张作用远程响应的结果。  相似文献   

3.
通过借助层序地层学理论、构造古地貌分析、古生物资料、沉积速率与可容纳空间关系对比,以及典型地震相识别、地震相与沉积相剖面及平面分析等,结合区域地质资料及前人的研究成果,对白云南洼恩平组烃源岩的叠置关系、影响因素、空间展布规律及发育模式进行了研究,得到如下认识:白云南洼恩平组对应一个完整的二级层序,可细分为3个三级层序,自下至上为SQ1、SQ2、SQ3,海平面总体为上升特征,SQ3的最大海泛面对应了整个恩平组二级层序的最大海泛面;白云南洼恩平组为局限浅海环境,具备发育较好海相烃源岩的条件,稳定半封闭的古构造背景,有利于烃源岩有机质的富集保存;沉积速率小,且小于可容空间增长速率,沉积物向陆退积,沉积水体深度变大,利于海相烃源岩的发育;恩平组烃源岩为大陆边缘半闭塞—欠补偿—湿润海湾模式,优质烃源岩主要发育在受隆起及断层遮挡形成的海湾区。  相似文献   

4.
以二叠系为研究对象,基于野外露头、钻井资料和地震资料,以沉积相分析为核心,以组为单位编制了下扬子-南黄海二叠纪岩相古地理图,并在此基础上,预测有利烃源岩和储层分布,分析二叠系勘探潜力及勘探方向。研究结果表明:下扬子地区二叠纪为稳定的被动大陆边缘型构造背景,其古地理特征总体呈现的地势为沿NE-SW向展布的轴部低、西北及东南两侧较高的沉积面貌和格局,主要发育三角洲相、滨岸-沼泽相、局限台地相、开阔台地相和斜坡-盆地相等主要优势相;根据烃源岩与岩相古地理之间的对应关系,推测龙潭组煤系烃源岩主要发育于下扬子陆区的安徽东南部到江苏东南部、海区的南黄海盆地中部,综合评价其有机质丰度高、平面分布稳定、厚度大,是二叠系重要的烃源岩发育层段;指出崂山隆起的东南部和东部紧邻生烃中心,三角洲储层发育,油气运移条件优越,晚期保存条件好,是有利勘探靶区。  相似文献   

5.
南海北部神狐海域天然气水合物形成及分布的地质因素   总被引:6,自引:0,他引:6  
从天然气水合物发育的地质构造条件、沉积条件、气源条件、温压条件等分析了神狐海域影响水合物形成及分布的地质因素.指出神狐海域处在洋陆壳的过渡带上,断裂-褶皱构造及流体底辟构造发育,对水合物的形成具有重要的控制作用.受等深流和海底滑塌双重作用,研究区沉积异常体发育,沉积厚度大、沉积速率高,有利于水合物发育.通过对神狐海域附近钻探结果及区内地质调查站位资料的分析表明:目标区具有含巨量的生物气和热成因气资源潜力,具备形成天然气水合物的气源条件,气源为文昌-恩平组烃源岩.此外,受热流值北高南低的分布格局的影响,神狐海域BSR埋深也表现为北部浅南部深,且BSR分布区整体处在天然气水合物稳定存在的温压范围内,满足水合物形成及保存所需的温压条件.神狐海域的地质构造条件、沉积特征、气源条件、温压条件等都非常有利于天然气水合物发育.  相似文献   

6.
琼东南盆地华光凹陷构造特征及沉积充填   总被引:4,自引:0,他引:4  
南海北部大陆边缘发育多个新生代含油气盆地。近年来,在南海北部珠江口盆地南部深水区陆续发现大中型气藏,证实了该区油气地质条件优越。琼东南盆地南部深水区与珠江口盆地深水区具有相似的构造沉积演化史,油气地质条件相似,具有形成大中型油气藏的地质条件,因此十分有必要开展该区的构造特征及沉积充填研究。基于近年来新采集的高精度地震资料,对华光凹陷构造特征进行详细分析,认为区内发育4种伸展构造样式,分别是地堑、半地堑、多米诺式半地堑和地垒;经历两个构造演化阶段,形成"下断上拗"的双层结构特征,相应发育两个期次的正断层。下构造层古近系受裂陷作用控制,断层发育,地层分布受断裂控制明显,上构造层新近系-第四系构造活动微弱,断层不发育,地层变形小且沉积厚度趋于稳定。华光凹陷古近系为河湖相-海陆过渡相沉积,其中下渐新统崖城组煤系地层是琼东南盆地勘探证实的主要烃源岩层系,上渐新统陵水组是主要储层发育时期,新近系-第四系为浅海-半深海-深海相沉积,其中中新统储层发育,上中新统及以上海相泥岩是良好的盖层。因此,华光凹陷具有良好的生储盖组合。  相似文献   

7.
珠江口盆地恩平凹陷恩平组是重要的油气储层,但受钻井资料较少且分布不均匀的限制,应用常规手段无法进行精细的储层预测。利用地震多属性分析技术,结合测井曲线及区域地质资料,对恩平凹陷恩平组进行了精细的地震解释。根据珠江口盆地恩平凹陷高精度的三维地震和钻井等资料,将恩平组分为PSQ1、PSQ2、PSQ3 3个三级层序。基于建立的等时层序地层格架,表明恩平组发育辫状河三角洲相、扇三角洲相和滩坝相3种类型的沉积相。研究成果对恩平凹陷下步的油气勘探具有重要的指导意义。  相似文献   

8.
根据钻井岩心、测井、地震和古生物等资料,对瓯江凹陷古近系地层的沉积相类型和沉积演化特征进行了系统分析.结果表明,瓯江凹陷古近系发育三角洲相、扇三角洲相、湖泊相、滨海相和浅海相5种沉积相类型.根据该区构造演化特征和沉积充填特征,可将瓯江凹陷古近系沉积演化分为3个阶段:早古新世断层开始活动,形成了凹陷雏形,总体发育三角洲—...  相似文献   

9.
南海北部珠江口盆地恩平凹陷大面积三维地震资料揭示了新近系类型丰富的砂体,在古珠江三角洲演化及相带迁移的控制下形成了较好的岩性圈闭发育条件。近年来,凹陷内发现的多个构造-岩性圈闭均与河道砂体相关。但在已有的层序地层划分方案中,河道砂体的成因、分类和展布特征与体系域的耦合关系差,砂体发育规律不明,制约了岩性圈闭的勘探效果。基于沉积层序理论,利用大范围井震资料,系统厘定了恩平凹陷珠江组一段-韩江组六段的高精度层序地层框架,并在此基础上开展了精细的三维地震沉积学解剖。分析结果显示,目的层发育的大型辫状河道、小型曲流河道和中型曲流河道,分别与低位、海侵和高位等特定体系域具有密切的耦合发育关系,进而建立了层序格架对河道砂体的有效预测模式,系统指明了凹陷不同区域、不同体系域内岩性圈闭的发育潜力及有利区。本文相关认识对其他海相三角洲盆地岩性圈闭勘探具有启示作用。  相似文献   

10.
珠Ⅲ次盆地是南海北部陆架珠江口盆地三个次盆地中的一个,为形成于早第三纪的裂谷盆地,是珠江口盆地早第三纪断陷湖群的一部分。珠Ⅲ次盆地的演化可以分为三期:早期湖相(古新世-中渐新世)、中期海湾相(晚渐新世)和晚期开放浅海相(晚第三纪)。依次形成生油层、储集层和盖层。湖相沉积包括文昌组(油源岩)和恩平组(气源岩),是研究区两个石油系统的源岩区。珠Ⅲ次盆地经历了三次显著的构造运动,其中晚渐新世的张性—剪切运动和中中新世末期的拉张运动导致研究区主要含油构造的形成。油气勘探、两种源岩地球化学和热模式综合分析…  相似文献   

11.
本文系统介绍了珠江口盆地最南的一个探井——BY7—1—1井浮游有孔虫生物地层和海侵层序。通过对该井有孔虫全面系统采样分析,发现了渐新世浮游有孔虫组合。这一重大发现给重新认识该区上、下第三系界线,以及对整个南海北部地层对比提供了新资料。并对有关的一些地质问题进行了讨论。  相似文献   

12.
珠江口盆地的扩张旋回及其与含油气性的关系   总被引:1,自引:0,他引:1  
根据“陆缘扩张”观点,扩张型陆缘演化阶段的三个构造旋回与珠江口盆地的油气生成和聚集密切相关。第一扩张旋回中形成的始新统文昌组泥岩是珠江口盆地的主要烃源岩。由文昌组排出的油气,经运移上升至第三扩张旋回中形成的中中新统韩江组泥岩盖层之下。运移过程中,油气主要进入由第二扩张旋回中形成的上渐新统珠海组和下中新统珠江组为储层的有利圈闭中。因此,珠江组和珠海组是珠江口盆地的重要目的层,而“拗中隆”及生物礁-滩则是钻探的主要对象。  相似文献   

13.
The identification of a deeply-buried petroleum-source rock, owing to the difficulty in sample collection, has become a difficult task for establishing its relationship with discovered petroleum pools and evaluating its exploration potential in a petroleum-bearing basin. This paper proposes an approach to trace a deeply-buried source rock. The essential points include: determination of the petroleum-charging time of a reservoir, reconstruction of the petroleum generation history of its possible source rocks, establishment of the spatial connection between the source rocks and the reservoir over its geological history, identification of its effective source rock and the petroleum system from source to trap, and evaluation of petroleum potential from the deeply-buried source rock. A case study of the W9-2 petroleum pool in the Wenchang A sag of the Pearl River Mouth Basin, South China Sea was conducted using this approach. The W9-2 reservoir produces condensate oil and gas, sourced from deeply-buried source rocks. The reservoir consists of a few sets of sandstone in the Zhuhai Formation, and the possible source rocks include an early Oligocene Enping Formation mudstone and a late Eocene Wenchang Formation mudstone, with a current burial depth from 5000 to 9000 m. The fluid inclusion data from the reservoir rock indicate the oil and the gas charged the reservoir about 18–3.5 Ma and after 4.5 Ma, respectively. The kinetic modeling results show that the main stages of oil generation of the Wenchang mudstone and the Enping mudstone occurred during 28–20 Ma and 20–12 Ma, respectively, and that the δ13C1 value of the gas generated from the Enping mudstone has a better match with that of the reservoir gas than the gas from the Wenchang mudstone. Results from a 2D basin modeling further indicate that the petroleum from the Enping mudstone migrated upward along the well-developed syn-sedimentary faults in the central area of the sag into the reservoir, but that the petroleum from the Wenchang mudstone migrated laterally first toward the marginal faults of the sag and then migrated upward along the faults into shallow strata. The present results suggest that the trap structure in the central area of the sag is a favorable place for the accumulation of the Enping mudstone-derived petroleum, and that the Wenchang mudstone-derived petroleum would have a contribution to the structures along the deep faults as well as in the uplifted area around the sag.  相似文献   

14.
渤海湾盆地渤中凹陷古近系沉积体系演化及物源分析   总被引:22,自引:0,他引:22  
综合运用地质、测井、地震及分析化验等资料,对渤海湾盆地渤中凹陷古近系沉积体系进行了较深入的研究,研究表明渤中凹陷古近系的沉积体系主要受构造升降和湖平面变化的控制,经历了3期裂陷和湖侵,发育5套沉积体系,其中沙河街组沉积时期为裂陷期,以扇三角洲、湖底扇沉积为主,并发育特征的滩坝及浅水台地相沉积;东营组沉积时期为湖侵期,主要发育大型湖泊三角洲沉积,并逐渐向辫状河相过渡。构造及沉积体系分析认为,沙三段沉积时期物源丰富,主要来自石臼坨凸起、渤南和庙西凸起,沙一、二段沉积时期物源有限,东三沉积期物源主要来自石臼坨和沙东南凸起,东二沉积期大面积的湖侵使得本区处于浅湖-半深湖环境,凹陷周边大量古水系将石臼坨凸起、沙垒田凸起的物源带入凹陷中沉积,使得大型三角洲叠覆体广泛发育。  相似文献   

15.
Switched sequence stratigraphic architectural units were developed in the Eocene Wenchang Formation stratigraphic section of the Pearl River Mouth Basin (PRMB), northern South China Sea. Utilizing a high-quality 3D seismic data set, well logs and restored paleogeomorphology, the architecture and genesis of switched sequence stratigraphic units have been systematically investigated. The Wenchang Formation, a second-order sequence, can be subdivided into seven third-order sequences (from base to top: SQ1, SQ2, SQ3, SQ4, SQ5, SQ6, and SQ7). The sequence stratigraphic architecture of the Wenchang Formation is characterized by continuous lateral stacking patterns from sequences SQ1 to SQ7. Sequences SQ1–SQ4 mainly developed in the HZ26 sag, whereas sequences SQ5–SQ7 mainly developed in the XJ24 sag. The depositional centres of the Wenchang Formation appear to have migrated from the HZ26 sag to the XJ24 sag-along the northwest direction from sequences SQ1 to SQ7. Multiple tectonic activation episodes or alternating tectonic subsidence of the HZ26 and XJ24 sags resulted in the distinctive geomorphological features that effected the development of the switched sequence stratigraphic architecture in the study area. The switched sequence stratigraphic architecture presented in this study may provide new insights into a better understanding of sequence stratigraphic stacking patterns in continental lacustrine rift basins.  相似文献   

16.
The Sergi Formation (Upper Jurassic) represents the main hydrocarbon reservoir of the Recôncavo Basin, Brazil. The basal vertical facies succession of the Sergi Formation comprises reservoirs formed by a complex fluvio–aeolian–lacustrine interaction. Facies architecture and detailed petrophysical analysis of these reservoirs have enhanced the understanding of heterogeneity at a variety of scales and has allowed the development of predictive models that describes the range of styles of mixed fluvial–aeolian reservoirs. At megascopic scale, the reservoirs are predominantly composed of sand bodies deposited by fluvial channel and aeolian facies associations. Regional flooding surfaces and sequence boundaries are their main flow barriers. The regional flooding surfaces are composed of fine-grained sediments deposited by lacustrine facies associations and the sequence boundaries act as flow barriers due to mechanically infiltrated clays. Based on its geometrical relations, reservoirs linked to fluvial–aeolian–lacustrine interaction formed two types of reservoirs at macroscopic scale: (i) with good lateral continuity of aeolian packages and relatively simple stratigraphic correlation and (ii) of highly compartmentalized aeolian packages with complex stratigraphic correlation and truncation by fluvial deposits. Mesoscopic heterogeneity reflects lithofacies, sedimentary structures, and lamina-scale variability within aeolian and fluvial facies associations.  相似文献   

17.
Dissolution mechanism and favorable reservoir distribution prediction are the key problems restricting oil and gas exploration in deep-buried layers. In this paper, the Enping Formation and Zhuhai Formation in Baiyun Sag of South China Sea was taken as a target. Based on the thin section, scanning electron microscopy, X-ray diffraction, porosity/permeability measurement, and mercury injection, influencing factors of dissolution were examined, and a dissolution model was established. Further, high-quality reservoirs were predicted temporally and spatially. The results show that dissolved pores constituted the main space of the Paleogene sandstone reservoir. Dissolution primarily occurred in the coarse- and medium-grained sandstones in the subaerial and subaqueous distributary channels, while dissolution was limited in fine-grained sandstones and inequigranular sandstones. The main dissolved minerals were feldspar, tuffaceous matrix, and diagenetic cement. Kaolinization of feldspar and illitization of kaolinite are the main dissolution pathways, but they occur at various depths and temperatures with different geothermal gradients. Dissolution is controlled by four factors, in terms of depositional facies, source rock evolution, overpressure, and fault activities, which co-acted at the period of 23.8–13.8 Ma, and resulted into strong dissolution. Additionally, based on these factors, high-quality reservoirs of the Enping and Zhuhai formations are predicted in the northern slope, southwestern step zone, and Liuhua uplift in the Baiyun Sag.  相似文献   

18.
应用层序地层学方法,通过钻井、测井、地震反射等标志,识别出层序界面和最大海泛面,将东海陆架盆地瓯江凹陷古近系划分为3个层序,层序界面分别为T20、T40、T42、T50,并以地层叠置样式、岩性、岩相的变化为依据在单井上将每个三级层序细分为低位、湖侵和高位3个体系域;在层序格架内利用钻井和古生物资料分析了沉积体系在瓯江凹陷的平面展布:月桂峰组主要是三角洲相和湖泊相沉积,灵峰组和明月峰组是三角洲相和滨海相沉积,瓯江组和温州组为三角洲相和滨海相沉积,其中瓯江凹陷东次凹为浅海相沉积;沉积物源主要以西向东注入和西北方向向东南注入,同时揭示了古近系两次大规模海侵分别是古新世中期灵峰组沉积时期和始新世中期瓯江组沉积时期。  相似文献   

19.
In this study, element geochemistry and zircon chronology are used to analyze the Oligocene sediments in the Baiyun Sag, Zhujiang River Mouth Basin. The experimental results are discussed with respect to weathering conditions, parent rock lithologies, and provenances. The chemical index of alteration and the chemical index of weathering values of mudstone samples from the lower Oligocene Enping Formation indicate that clastic particles in the study area underwent moderate weathering. Mudstone samples exhibit relatively enriched light rare earth elements and depleted heavy rare earth elements, "V"-shaped negative Eu anomalies, and negligible Ce anomalies. The rare earth element distribution curves are obviously right-inclined, with shapes and contents similar to those of post-Archean Australian shale and upper continental crust, indicating that the samples originated from acid rocks in the upper crust. The Hf-La/Th and La/Sc-Co/Th diagrams show this same origin for the sediments in the study area. For the samples from the upper Enping deltas, the overall age spectrum shows four major age peaks ca. 59–68 Ma, 98–136 Ma, 153–168 Ma and 239–260 Ma. For the Zhuhai Formation samples,the overall age spectrum shows three major age peaks ca. 149 Ma, 252 Ma and 380 Ma. The detrital zircon shapes and U-Pb ages reveal that during Oligocene sedimentation, the sediments on the northwestern margin of the Baiyun Sag were supplied jointly from two provenances: Precambrian-Paleozoic metamorphic rocks in the extrabasinal South China fold zone and Mesozoic volcanic rocks in the intrabasinal Panyu Low Uplift, and the former supply became stronger through time. Thus, the provenance of the Oligocene deltas experienced a transition from an early proximal intrabasinal source to a late distal extrabasinal source.  相似文献   

20.
东海陆架盆地台北坳陷月桂峰组生物地层及古环境   总被引:6,自引:0,他引:6  
月桂峰组分布于台北坳陷西带,上覆灵峰组、下伏石门潭组,由灰黑色泥岩、砂岩组成。在微体古生物和地球化学微量元素详细分析的基础上,确立它属古近纪古新世沉积,推测可能为古新世早期,该地层相当于苏北盆地阜宁组一段。月桂峰组所含孢粉、藻类化石组合及地球化学微量元素特征表明月桂峰组当时的沉积环境以淡水湖相为主,局部时期(晚期)可能演变成海陆交互相,或者受到海水的影响。  相似文献   

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