同向和反向断层形成机制及控圈作用差异性

油田勘探开发实践证实斜坡区同向和反向断层圈闭均是油气勘探的潜力区。以束鹿斜坡西曹固构造带为研究靶区,从断层变形机制出发,结合断层分段生长理论,系统探讨斜坡区同向和反向断层形成机制及控圈作用差异性。研究结果表明:由于断层差异活动和分段生长作用,反向断圈形成于下盘分段生长点之间,而同向断层圈闭形成于上盘分段生长点上;基于断圈面积和断距的关系分析,认为反向断层控圈面积和幅度明显大于同向断层。     

源外斜坡区顺向和反向断裂控藏差异性——以渤海湾盆地冀中坳陷文安斜坡中南部为例

以渤海湾盆地冀中坳陷文安斜坡中南部为例,研究含油气盆地源外斜坡区不同产状断裂对油气成藏与分布的控制作用。以三维地震资料为基础,结合油水分布规律,从断裂形成演化规律和断层圈闭形成机理入手,对比分析顺反向断裂的断层圈闭发育部位、垂向调整油气分布层位和断层圈闭形成时期的差异。研究表明,源外斜坡区顺向和反向断裂控藏差异性主要表现为3个方面:(1)顺向和反向断层圈闭发育部位不同,顺向断层圈闭发育在处于"硬连接"阶段的断裂上盘,其分段生长点处为断层圈闭发育部位,而反向断层圈闭受地层掀斜作用发育在断裂下盘断距最大部位;(2)顺向和反向断层圈闭形成时期不同,顺向断层圈闭形成时期为断裂开始进入"硬连接"阶段时期,而反向断层圈闭形成时期即为断裂开始活动时期;(3)顺向和反向断裂垂向调整油气分布层位不同,顺向断裂垂向调整油气后,油气分布具有单层和多层分布的特征,而反向断裂垂向调整油气通常表现为单层分布特征。     

源外斜坡区顺向和反向断裂控藏差异性研究——以渤海湾盆地冀中坳陷文安斜坡中南部为例

以渤海湾盆地冀中坳陷文安斜坡中南部为例,研究含油气盆地源外斜坡区不同产状断裂对油气成藏与分布的控制作用。以三维地震资料为基础,结合油水分布规律,从断裂形成演化规律和断层圈闭形成机理入手,对比分析顺反向断裂的断层圈闭发育部位、垂向调整油气分布层位和断层圈闭形成时期的差异。结果表明,源外斜坡区顺向和反向断裂控藏差异性主要表现为3个方面:(1)顺向和反向断层圈闭发育部位不同,顺向断层圈闭发育在处于“硬连接”阶段的断裂上盘,其分段生长点处为断层圈闭发育部位,而反向断层圈闭受地层掀斜作用发生在断裂下盘断距最大部位;(2)顺向和反向断裂垂向调整油气分布层位不同,顺向断裂垂向调整油气后,油气分布具有单层和多层分布的特征,而反向断裂垂向调整油气通常表现为单层分布特征;(3)顺向和反向断层圈闭形成时期不同,顺向断层圈闭形成时期为断裂开始进入“硬连接”阶段时期,而反向断层圈闭形成时期即为断裂开始活动时期。顺反向断裂控藏作用的差异性研究为源外斜坡区油气勘探部署提供了理论基础。     

不同类型断层控制油气垂向富集的差异——以渤海湾盆地歧口凹陷歧南斜坡区为例

渤海湾盆地历经多期构造变动，断层圈闭发育普遍。断层作为断层圈闭的边界条件，在油气成藏过程中起着至关重要的作用。以断层圈闭较发育的歧南斜坡区为例分析了同向断层和反向断层控制油气垂向富集的差异，基于三维地震资料，从断层形成过程和断层圈闭分布出发，剖析了断层遮挡圈闭的成因及分布规律。结合油水分布规律，基于油藏解剖并应用储层定量荧光技术明确了不同类型断层控藏的差异及其形成机理。研究表明：①断层分段生长作用和断层上盘与下盘的差异活动是同向断层控制下断层遮挡圈闭形成的主要原因，斜坡区反向断层控制形成的断层圈闭则是断块掀斜翘倾作用所致；②同向断层圈闭发育在断层上盘分段点位置，只有当同向断层进入"硬连接"阶段方可形成断层圈闭，反向断层圈闭形成在断层下盘，在反向断层活动初期便可形成；③同向断层既可以控制油气在多套含油气系统中聚集成藏，也可在一套含油气系统中富集，而反向断层往往控制油气在一套含油气系统中富集；④不同类型断层控制油气垂向聚集的差异与圈闭发育位置以及断-盖配置有关。采用泥岩涂抹系数对沙河街组一段中部盖层控制的含油气系统的垂向调整进行定量评价，泥岩涂抹系数低于3.5时油气保存，泥岩涂抹系数高于3.5时油气垂向渗漏。     

分段生长模式下断层边部微幅度构造分析

文中以松辽盆地杏北开发区F278b断层为例,优选Surfer软件6种插值方法,生成葡I11层构造等值线图。以三维地震精细解释为基础,读取线道号数据与断距数据,编制距离-断距曲线图,确定断层横向分段位置。以断圈形成机制为指导,寻找断层分段生长部位与断层边部的微幅度构造分布规律,统计发育微幅度构造位置的井与分段生长点附近井的砂地比,系统分析断层横向分段生长位置、地层能干性差异与微幅度构造的关系。研究结果表明:1)Surfer软件6种插值方法中,最小曲率法在断层边部、井位控制区域内部、边界部位等与实际情况相比较符合;2)断层下盘的微幅度构造与上盘的微幅度构造受断层横向分段生长影响,呈正弦曲线分布关系,交替出现;3)断层边部上盘负向微幅度构造处砂岩体积分数较高,下盘正向微幅度构造处与断层分段生长点附近砂岩体积分数比较低。     

逆断层和聚敛型扭断层下盘圈闭条件分析及勘探意义

在压扭性含油气盆地勘探中，早期主要集中在断褶构造带的构造高部位，并已找到了许多断背斜、断鼻型油气藏；但随着勘探的深入。不得不考虑这些断褶构造下盘由逆断层和聚敛型扭断层封闭所形成的断层圈闭。虽然断层下盘圈闭在数量上和总的油气储量上一般都要比断层上盘背斜圈闭的低。但有时断层下盘的圈闭可以形成储量很大的油气藏，目前国内外均找到了这类油气藏。对柴达木盆地西部阿尔金走滑断裂带圈闭条件的实例研究，进一步明确了由逆断层和聚敛性扭断裂封闭的断层下盘圈闭是构造—岩性油气藏形成的有利部位．是一个位得重视的油气勘探新领域。     

泥岩涂抹效应及对断层封闭性的控制作用——以石西11—石西6井区为例

根据区域构造演化和地层发育特征综合分析认为,由于石西地区石西11井区J2x-K1q段发育较低倾角、小断距断层及较高的泥地比值,造成了导油断裂在该井区J2x-K1q段地层发育泥岩涂抹层形成断层封闭,阻止了下部油气沿该导油断裂运移至下盘高部位的石西11井K1q圈闭成藏,由该泥岩涂抹形成的断层封闭也同时阻止了油气向石西6井同一盘上部层位K1q圈闭的运移成藏。研究泥岩涂抹效应对研究区及类似地区的油气勘探有一定的帮助。     

断块圈闭控藏模式——以辽河盆地西部凹陷为例

中国东部断块圈闭油气资源丰常丰富,通过对辽河盆地西部凹陷179个断块圈闭解剖,阐述了断块油气藏的基本特征及其分布的主控因素.按成因类型将断块圈闭划分2大类共计5种类型,即层内同层砂岩对接、层内异层砂岩对接、层外反向断层砂岩对接、层外同向断层砂岩对接和砂泥岩对接,并对其成因机制进行了探讨;在同向和反向断层控藏特征分析基础上,认为影响断块圈闭的3个主要因素是断层垂直断距、储层砂岩视厚度和盖层泥岩视厚度,并且指出三者之间的相互关系与断层圈闭的大小和形态密不可分,进而提出了断块圈闭三元耦合控藏模式,并对其进行了验证.     

泥岩涂抹效应及对断层封闭性的控制作用———以石西11—石西6井区为例

根据区域构造演化和地层发育特征综合分析认为,由于石西地区石西11 井区J_2x-K_1q 段发育较低倾角、小断距断层及较高的泥地比值,造成了导油断裂在该井区J_2x-K_1q 段地层发育泥岩涂抹层形成断层封闭,阻止了下部油气沿该导油断裂运移至下盘高部位的石西11 井K_1q 圈闭成藏,由该泥岩涂抹形成的断层封闭也同时阻止了油气向石西6 井同一盘上部层位K_1q 圈闭的运移成藏。研究泥岩涂抹效应对研究区及类似地区的油气勘探有一定的帮助。     

辽河滩海东部勘探有利圈闭特征

由于郯庐断裂带的多期走滑活动,滩海地区东部的构造演化、圈闭形成过程相对复杂。通过对辽河滩海地区东部构造演化过程分析,认为研究区主要发育了3种类型的圈闭:1)前古近纪时期,潜山内幕发育了一系列近东西向的反向翘倾断块圈闭,在渐新世时期可以依靠燕南断层走滑活动接受来自东部凹陷内的油气运聚保存后成藏,形成中、古生界圈闭;2)渐新世时期,走滑作用对燕南断层进行改造,同时潜山抬升,东营组地层沿着燕南断层形成一系列断鼻圈闭;3)上新—更新世时期,研究区内发生剪切走滑作用对馆陶组地层圈闭改造,形成了馆陶组构造地层圈闭。按照有利圈闭以及经济勘探的原则,给出了建议钻探目标区域。     

西湖凹陷西斜坡断层-岩性圈闭形成条件探讨

随着勘探程度的深入，西湖凹陷西斜坡全面进入了岩性圈闭勘探阶段，西斜坡主要勘探层系始新统经历了强烈的断陷-断拗转换期，断层相关的断层-岩性圈闭为主要的岩性圈闭类型，为了寻找规模岩性油气藏富集区，需要认识到断层-岩性圈闭的形成条件。此文通过针对断层-岩性圈闭的构造沉积演化及控砂模式研究，认为斜坡带西高东低的地貌背景造成物源自西向东推进，形成的潮坪-潮控三角洲共生的沉积环境下发育的 三角洲分支河道、潮坪砂和潮道等多种类型的砂体，在断裂和地貌的控制下形成顺向主断裂下降盘陡坡砂岩上倾尖灭-断层侧翼封堵圈闭、多级顺向断层下降盘断层上倾封堵-砂岩侧翼尖灭圈闭、反向断层下降盘砂岩上倾尖灭-断层侧翼封堵圈闭、反向断层上升盘断层上倾封堵-砂岩侧翼尖灭圈闭四种类型的断层-岩性圈闭。     

渤海湾盆地渤中凹陷油藏断裂特征及对成藏的控制作用

渤中凹陷是环渤海湾盆地的沉积沉降中心,也是环渤海湾盆地重要的富油气凹陷之一。目前在凹陷周边所发现的油藏绝大部分是受断裂控制的构造或构造-岩性油气藏,这些断裂对油气藏的控制方式和影响程度,直接决定构造圈闭的评价结果和勘探部署方案。对渤中凹陷目前已发现的237个中浅层油气藏构造特征进行精细解剖,统计对比了断裂的级别、成因类型、断距、断层活动性、断层产状、组合样式、平面形态、遮挡类型、断层泥比率等指标与相应的油藏发育程度,发现在主断裂与次级断裂的合理配置的前提下,渤中凹陷中浅层有利于成藏的断裂特征为：走向NNE、近EW和NE,倾角66°~80°,断距20~150 m,断层活动速率在10~30 m/Ma,断层泥比率SGR大于0.3,断裂带泥质含量R_m大于0.35,组合样式为斜交式、雁列式、Y字形、似花状和阶梯状,并且断裂以反向遮挡为主。平面上在断裂相交处、凸形增压段更有利于油气聚集成藏。本质上说,断层封闭性是控制构造圈闭成藏的关键,断裂活动速率、规模和断裂类型是影响封闭性的根源。     

海南福山凹陷顺向和反向断裂控藏机理及油气聚集模式

对于不同产状的断裂,其油气成藏控制机理与结果的差异很大。福山凹陷主体地区发育深层反向和浅层顺向两大断裂系统。前者形成时间早,活动性差,断距大小适合,有利于形成多种圈闭和对油气的遮挡成藏,控制了福山凹陷绝大多数油气藏的形成与分布;后者形成时间晚,长期多期活动,断层遮挡油柱高度小,不利于油气的聚集和保存。深层反向断裂控制的油气藏位于断裂下盘,浅层顺向断裂控制的油气藏位于断裂上盘,油气主要富集在深层反向断裂控制的下盘圈闭中。     

断层开启与封闭的定量分析

断层的开启与封闭性与断面正压力和流体压力的耦合关系有关,据此可建立断层开启与封闭的定量数学模型,并可计算断层的封闭系数。根据模型,影响断层开启和封闭的因素主要有构造应力,断层的走向、倾角、深度,两盘岩性,流体压力等。研究表明,随着异常流体压力系数的增大、构造挤压力的减小、岩石泊松比的减小,断层的封闭性都会降低。另外,断层倾角和深度对断层封闭性的影响受构造应力性质控制,在张性盆地中,断层的封闭性随着深度的增加而增加,随倾角增大而减小;在压性盆地中则相反。断层走向对断层封闭性的影响随差异应力增大而增强。     

Impact of structural setting on hydrocarbon trapping mechanism of onshore Niger Delta basin,Nigeria, using seismic attribute analysis

The evaluation of hydrocarbon trapping system in an onshore Niger Delta basin, Nigeria was studied using well log and seismic data. This is very important in estimation of production cost and assessment of viable reservoir units in petroleum industry. It is the main aim in reservoir characterization, in order to estimate the geometry and trapping mechanism of any particular field under investigation. These were achieved through the integration of 3D seismic and well log data that was acquired from an Onshore Niger Delta basin, Nigeria. From the well logs, three reservoir units was identified namely RS1, RS2, RS3 and these were mapped based on the curve signatures of the geophysical logs. These identified hydrocarbon bearing intervals were mapped on the seismic section using checkshot dataset for time to depth conversion. Four horizons and a total of thirteen fault traces were mapped within the region, with two characterized building structural faults of F2 and F3 features. Fault F4 and F7 are antithetic fault that trends north east to south west and the trapping mechanisms for the region are both a four way closure and fault assisted closure, as the trap is an up dip fault closure against the up thrown side of fault F8. Amplitude, variance and coherence attributes shows the faulting structure of hydrocarbon migration channels and path ways, through which hydrocarbon migration and accumulation occurs within the region. A significant level of contribution was achieved with the variance attributes showing a better resolution of an instant fault detection or identification compared to other attributes studied within the field of interest. The identified hydrocarbon bearing units lies within the same depth across the entire wells. This proved that the region has exhibits little or no tectonic deformation. The presence of structural features such as antithetic and synthetic is responsible for the hydrocarbon entrapment within the region. A detailed analysis of the study location revealed highly faulted region that exhibits a typical Niger Delta tectonic settings.     

Characteristics of fault zones and their control on remaining oil distribution at the fault edge: a case study from the northern Xingshugang Anticline in the Daqing Oilfield,China

Most major oil zones in the Daqing Oilfield have reached a later, high water cut stage, but oil recovery is still only approximately 35 %, and 50 % of reserves remain to be recovered. The remaining oil is primarily distributed at the edge of faults, in poor sand bodies, and in insufficiently injected and produced areas. Therefore, the edge of faults is a major target for remaining oil enrichment and potential tapping. Based on the dynamic change of production from development wells determined by the injection–recovery relationship at the edge of faults, we analyzed the control of structural features of faults on remaining oil enrichment at the edge. Our results show that the macroscopic structural features and their geometric relationship with sand bodies controlled remaining oil enrichment zones like the edges of NNE-striking faults, the footwalls of antithetic faults, the hard linkage segments (two faults had linked together with each other to form a bigger through-going fault), the tips of faults, and the oblique anticlines of soft linkages. Fault edges formed two types of forward microamplitude structures: (1) the tilted uplift of footwalls controlled by inverse fault sections and (2) the hanging-wall horizontal anticlines controlled by synthetic fault points. The remaining oil distribution was controlled by microamplitude structures. Consequently, such zones as the tilted uplift of the footwall of the NNW-striking antithetic faults with a fault throw larger than 40 m, the hard linkage segments, the tips of faults, and the oblique anticlines of soft linkage were favorable for tapping the remaining oil potential. Multi-target directional drilling was used for remaining oil development at fault edges. Reasonable fault spacing was determined on the basis of fault combinations and width of the shattered zone. Well core and log data revealed that the width of the shattered zone on the side of the fault core was less than 15 m in general; therefore, the distance from a fault to the development target should be larger than 15 m. Vertically segmented growth faults should take the separation of the lateral overlap of faults into account. Therefore, the safe distance of remaining oil well deployment at the fault edge should be larger than the sum of the width of shattered zone in faults and the separation of growth faults by vertical segmentation.     

渤海辽东湾海域JZ25-1S转换带与油气成藏的关系

根据新的三维地震资料解释结果,运用断层的位移-距离分析法,探讨了渤海辽东湾JZ25-1S转换带的变形特征,并分析了转换带与油气聚集的关系。JZ25-1S地区断裂发育,主要为北东走向,平面上呈雁列式排列。倾向相同的辽西1号断层、2号断层和3号断层在叠覆区形成了属于转换斜坡型的JZ25-1S构造转换带,并在斜坡背景上发育有断块构造。JZ25-1S转换带等变形体变换了辽西1号、辽西2号和辽西3号分段断层传递的应力,使断块体在三维空间上保持应变守衡。JZ25-1S转换带对油气聚集成藏的作用主要包括:有利于构造圈闭的形成;控制沉积体系展布;有利于油气运移和改善储层质量。渤海地区同向叠覆型正断层之间发育的转换带是值得探索的有利油气勘探领域。