Petroleum Migration Characteristics in the Northeastern Part of the Baiyun Depression,Pearl River Mouth Basin,South China Sea

This paper investigates the origin and migration characteristics of petroleum in the northeastern part of the Baiyun Depression,Pearl River Mouth Basin(PRMB).The discovered petroleum in the study area is mainly located in the Lower Zhujiang Member(N₁z²)and mainly originated from the Enping Formation source rocks in the eastern sag.Active faults(vertical migration)and N₁z²sandstones(lateral migration)acted as the petroleum migration systems.The fault activities in the Dongsha event controlled the episodic petroleum migration.Fractures in the fault zones provided effective conduits,and overpressure was the driving force.The vertical migration could not cross the fault zones laterally.The petroleum injection areas in the carrier beds were the contact zones of petroleum-migration faults and carrier beds.The lateral migration was steady-state migration,and buoyancy was the driving force.The migration pathways in the carrier beds were controlled by the structural morphology.Secondary petroleum migration in the study area could be divided into two parts:vertical migration along the fractures in the fault zones and lateral migration through preferential petroleum migration pathways(PPMPs)in the carrier beds.The petroleum migration behaviors,including migrating direction,driving force,and migration pattern,in the faults and sandstone carrier beds were quite different.This study provides a typical example for comprehending secondary migration processes and has great importance for determining future exploration targets in the deep-water area of the PRMB.     

从断裂带内部结构出发评价断层垂向封闭性的方法

脆性断层和塑性断层断裂带内部结构存在差异: 脆性断层断裂带由以断层岩和伴生裂缝为特征的破碎带和诱导裂缝带2部分组成; 塑性断层断裂带表现为几条充填断层泥大裂缝的组合, 诱导裂缝带不发育.破碎带内部伴生裂缝、无粘结力断层岩带和诱导裂缝带都可能成为油气运移的通道, 只有这3种通道均封闭, 脆性断层垂向才是封闭的.只要伴生裂缝封闭, 塑性断层就是封闭的.基于这种封闭机理, 分析了3种通道封闭的条件: 无粘结力断层岩带是否封闭取决于断层泥含量大小; 破碎带内部伴生裂缝的封闭性取决于断面压力和断层泥塑性强度关系; 诱导裂缝带封闭程度受控于后期成岩充填的程度.提出了利用断面压力、断层泥的含量和塑性强度、后期成岩程度综合判定不同性质断层垂向封闭性评价方法.并利用该方法对克拉2构造F₁断层垂向封闭性进行了评价, 结果表明F₁断层垂向封闭性具有分段性: ①和③段均表现为脆性, 但①段因诱导裂缝没有被充填不封闭, ③段是封闭的; ②段是塑性断层, 垂向封闭性好.这是克拉2构造有大规模天然气聚集成藏的关键因素之一.      

轮古东走滑断裂破碎带结构及与油气关系

利用最新处理完成的轮古东300 km2叠前深度偏移地震资料,多手段识别出轮古东气田发育3期4组断裂。断裂控制了裂缝走向与裂缝发育密度,裂缝主要为高角度(45°~75°)构造窄裂缝,沿裂缝存在溶蚀,走向主要为NESW。纵向上,一间房组裂缝发育密度最大(14条/100 m),其次为鹰山组(6条/100 m)和良里塔格组(4条/100 m);平面上,裂缝主要分布在主干断裂周边1 km范围内,随着距断裂距离增大,裂缝发育强度(裂缝线密度)呈指数降低。在此基础上,综合考虑主干断裂及伴生裂缝发育特征,将轮古东断裂破碎带平面上划分为"羽状破碎带、转换破碎带、斜列破碎带、复合破碎带"4种结构,羽状破碎带分布面积最广,是油气最富集的区域,是目前高效井的集中分布区,围绕羽状破碎带的钻探为走滑断裂控储控藏研究和寻找新的油气富集区域提供了新思路。     

断裂附近源断砂空间配置油气运聚有利部位预测方法及其应用

为研究含油气盆地下生上储式断裂附近断砂空间配置圈闭中油气分布规律,在断裂附近源断砂空间配置油气运聚机理及有利部位研究的基础上,利用源岩排烃分布区和断裂输导油气有利部位,确定断裂附近源断空间配置油气运移有利部位;通过断裂侧向封闭分布部位和油气储集砂体发育部位,厘定断裂附近断砂空间配置油气圈闭部位,两者叠合建立了一套断裂附近源断砂空间配置油气运聚有利部位的预测方法,并将其应用于渤海湾盆地冀中坳陷廊固凹陷大柳泉地区旧州4条分支断裂附近沙三中下亚段源断砂空间配置油气运聚有利部位的预测中。结果表明:旧州4条分支断裂附近沙三中下亚段源断砂空间配置油气运聚有利部位主要分布在F9断裂、F8断裂中部西南及东北部局部和F7断裂西南部,有利于下伏沙四段源岩生成油气沿断裂附近源断空间配置油气运移有利部位向上覆沙三中下亚段断砂空间配置圈闭中运聚成藏,与目前旧州4条分支断裂附近沙三中下亚段已发现油气主要分布相吻合,表明该方法用于预测断裂附近源断砂空间配置油气运聚有利部位是可行的。     

松辽盆地继承性断裂带特征及其在油气聚集中的作用

松辽盆地沉积盖层发育三套断裂组合,即张性断块构造断裂组合、张性断块构造-滑脱型正断层组合断裂组合、扭动断裂组合。三套断裂组合主干断层具有继承发育特点,形成继承性发育断裂带。这些断裂带不仅控制了深部构造格局、中浅层沉积体系的发育与展布以及盖层的构造变形,而且对盆地油气系统中油气运移、聚集与保存发挥着重要作用,因此继承性发育断裂带周围是盆地油气的主要聚集区带。     

断裂输导体系研究现状及存在的问题

在前人研究成果的基础上,对断裂输导体系的内部结构、动力学机理、输导能力的控制因素、流体活动特征的识别、与其有关的优势通道等方面进行了综述.脆性断裂带内部的流体输导通道包括伴生裂缝、无黏结力的断层岩带和诱导裂缝3种类型,塑性断裂带只具有断裂伴生裂缝一种类型的输导通道.断裂带流体排驱的动力学机理包括突发性构造事件、超压与构造活动联控、超压主导和浮力驱动4种基本类型.气烟囱、沸腾包裹体、MnO等微量元素与包裹体均一温度异常等是判断或追踪断裂带流体活动特征的有效指标.与断裂输导体系有关的优势通道包括流向优势和断面优势两种类型,它们对油气的分布具有重要的控制作用.最后提出了断裂输导体系研究中存在的问题及进一步研究的方向.     

Fluid flow in cataclastic thrust fault zones in sandstones, Sub-Andean Zone, southern Bolivia

The Bolivian Sub-Andean Zone (SAZ) corresponds to a Neogene thrust system that affects an about 10-km thick Palaeozoic to Neogene siliciclastic succession. The analysis of macro and microstructures and cement distribution in thrust fault zones shows that they are sealed by quartz at depths >3 km, due to local silica transfer by pressure-solution/precipitation activated at temperatures >70–90 °C. At shallower depths, faults have remained open and could be preferential drains for lateral flow of carbonate-bearing fluids, as shown by the occurrence of carbonate cements in fractures and their host-sandstone. Due to decreasing burial, resulting from foothill erosion during fault activity, critically buried fault segments can be affected by non-quartz-sealed structures that post-date initial quartz-sealed structures. The integration of textural, fluid inclusion and isotopic data shows that carbonates precipitated at shallow depth (<3 km), low temperature (<80 °C) and relatively late during the thrusting history. Isotopic data also show that precipitation occurred from the mixing of gravity-driven meteoric water with deeper formation water bearing carbonate carbon derived from the maturation of hydrocarbon source rocks (Silurian and Devonian shales). The combined microstructural and isotopic analyses indicate that: (i) fluid flow in fault zones often occurred with successive pulses derived from different or evolving sources and probably related to episodic fault activity, and (ii) at a large-scale, the faults have a low transverse permeability and they separate thrust sheets with different fluid histories.     

Structural and statistical characterization of joints and multi-scale faults in an alternating sandstone and shale turbidite sequence at the Santa Susana Field Laboratory: Implications for their effects on groundwater flow and contaminant transport

This paper describes the properties of faults and fractures in the Upper Cretaceous Chatsworth Formation exposed at Santa Susana Field Laboratory and its surroundings (Simi Hills, California), where groundwater flow and contamination have been studied for over three decades.The complex depositional architecture of this turbidite consisting of alternating sandstones and shales, interacting with formative stress conditions are responsible for multi-scale fault hierarchies and permeable fractures in which nearly all groundwater flow occurs.Intensity and distribution of background fractures and their relation to bedding thickness are established for sandstones, the dominant lithology. The architecture of faults with increasing displacement is described, and relationships among fault dimensional parameters captured.Data from ∼400 boreholes and piezometers reveal the effect of faults and fractures on groundwater flow. Large hydraulic head differences, observed across fault zones with shale-rich cores, indicate these structures as cross-flow barriers. Moreover, hydraulic head profiles under ambient conditions, and pumping tests suggest strong hydraulic connectivity in all directions to depth of hundreds of meters.This outcrop-based structural characterization relates the horizontal hydraulic conductivity to the observed well-connected fracture network, and explains the strong vertical connectivity across low-hydraulic conductivity shales as faults and sheared fractures provide flow pathways.     

松辽盆地尚家油田葡萄花油层成藏过程的再认识

根据尚家油田尚9-4圈闭油气空间分布特征、油气成藏时期与断裂活动时期匹配关系,及原油生物标志化合物特征对比结果证实,尚家油田葡萄花油层原油不是尚家油田扶余、杨大城子油层原油通过断裂垂向运移注入的结果。钻井资料分析证实,尚家油田葡萄花油层的砂体虽然厚度小,但分布范围大,尚家油田葡萄花油层的原油是三肇凹陷青山口组源岩生成的油通过断裂沟通的砂体侧向运移至该区而成藏的。控制尚家油田葡萄花油层原油侧向运移聚集成藏的关键因素是断裂与砂体的组合形式:同向断层与砂体组合有利于油气进行长距离侧向运移;反向断层与砂体组合不利于油气的侧向运移,但利于形成断层遮挡圈闭,使油能够聚集起来。流体势场的空间分布同时控制着尚家油田葡萄花油层原油侧向运移及聚集的部位。     

莺歌海盆地DF1-1底辟断裂系统及其对天然气成藏的控制

莺歌海盆地的巨厚充填，高地温梯度及大规模的超压流体活动等特殊的地质背景，造就了DF1－1底辟构造的独特性，其内天然气的总体特征与底辟区的断裂系统存在着密切的联系。底辟区内的超压流体活动使其上覆地层产生众多的断裂和裂缝。这些垂向上的断裂和裂隙既构成了异常压力体系能量释放的主要通道。同时也形成了天然气运多的垂向输导体系。在断裂开启过程中上升的活动流体主要取决于断裂下延的深度及断裂上延所连通的中深一浅层的渗透性砂体，因此由断裂与砂体的相互配置所构成的输导体系在DF1－1气田的成藏中起着重要的作用。根据DF1－1的成藏特点，强调断裂系统与天然气运聚的相互促进关系，建立了断裂系统与天然气成藏关系模式。     

准噶尔盆地西北缘大侏罗沟走滑断层油气成藏效应

走滑断层判识及其油气成藏效应是当前构造地质学与石油地质学研究的热点。为进一步认识准噶尔盆地西北缘地区的控藏断层大侏罗沟走滑断层,对其进行了野外露头观察和地震剖面解释,以进一步明确其构造属性与边界,在此基础上,结合油层分布与原油性质及地球化学特征分析,讨论了其成藏效应。结果表明,大侏罗沟断层走滑特征明显,西端野外露头上断线平直、断面陡立、发育水平擦痕,东端地震剖面平面上发育"马尾状构造"、剖面上发育"花状构造"。据此重新限定了断层的边界,西以达尔布特断层为界,东以达探1井为界,全长约80km。大侏罗沟走滑断层对油气兼具横向和纵向输导效应,使得油气藏在平面上沿断层被动盘富集,纵向上呈"串珠状"分布,这可能是这类走滑断层所具有的普遍特征。据此,研究区一系列走滑断层的被动盘在下步勘探中值得重点关注。     

断层纵向输导与储层非均质性耦合控运模拟实验研究

在物理模拟实验的基础上探讨了断层输导能力与储层非均质性对油沿断层垂向运移和侧向分流的控制机理与模式。研究结果表明,断层输导能力与储层非均质性对油运移的控制本质上表现为“物性”（断层与储层渗透率比值）与“动力”对油垂向运移和侧向分流的耦合控制作用。两者对油的运移和纵向分布的耦合控制作用可概括为强输导能力断层-反韵律储层控运、弱输导能力断层-反韵律储层控运和强输导能力断层-正韵律储层控运3种模式。第一种模式中,油沿断层垂向运移的过程中不易侧向分流,油主要富集在直接位于区域性盖层之下的储层中;第二种模式中,油沿断层垂向运移的过程中较易侧向分流,油在纵向上各储层中均有一定的富集;第三种模式中,油沿断层垂向运移的过程中极易侧向分流,油大多富集在下部物性最好的储层中。     

查干凹陷中央构造带不同断阶带原油成熟度特征差异及其成因分析

查干凹陷中央构造带被巴润断裂系分隔成多个断阶,东侧第一断阶和第二断阶含油范围小而西侧第三断阶和第四断阶含油范围大。东部断阶原油成熟度高而西侧断阶原油成熟度低,表现为:第一断阶和第二断阶CPI大多数大于1.20,OEP多数大于1.30,Pr/Ph多数在0.60以下,Ph/nC_(18)普遍高于1.00;第三断阶和第四断阶CPI和OEP小于1.20,Pr/Ph多数在0.60以上,Ph/nC_(18)普遍小于1.00。通过规则甾烷分布特征和原油成熟度特征的分析,确定靠近洼陷的第三和第四断阶的原油更多来自于洼陷中心的烃源岩供烃,而第一断阶和第二断阶则主要是构造带本地烃源岩供烃。钻井、测井资料表明,断层发育诱导裂缝带和滑动破碎带,其中滑动破碎带物性较差,具有良好的封堵性能。非线性随机反演结果表明,巴润3号断层南段致密滑动破碎带稳定发育。断层生长指数研究表明,断层主要在苏二晚期活动,并且巴润3号断层活动性较弱。研究区断层SGR普遍在25%以上,在断层静止期具有良好的封闭性。烃源岩生排烃史模拟和流体包裹体均一温度分析表明,中央构造带主要成藏时间为苏二末期—银根早期,成藏期巴润3号断层由于活动强度较弱,同时沿着断层致密滑动破碎带发育,导致洼陷中形成的原油不易穿过3号断层继续向构造带东侧运移;因此第一断阶和第二断阶主要依赖本地烃源岩供烃,而第三第四断阶为洼陷中心供烃,烃源岩的差异最终导致了不同断阶带原油成熟度的差异。     

碳酸盐岩内断裂带结构及其与油气成藏

以野外观察描述为手段,系统研究了碳酸盐岩断裂变形机制的影响因素及断裂带结构演化过程,剖析了碳酸盐岩地层中断裂带结构与流体运移的关系。研究表明,影响碳酸盐岩内断裂变形机制的因素包括岩性、孔隙度、变形深度、温度、胶结作用、先存裂缝等,控制断裂带结构形成的因素包括滑动位移和破裂模式等。低孔隙度碳酸盐岩以裂缝发育为主,高孔隙度碳酸盐岩变形早期产生变形带,带内裂缝联接逐渐发育成断层带。随着埋藏深度的增加,断裂带结构不同：埋藏深度小于3 km,断层核主要发育无内聚力的断层角砾岩和断层泥;埋藏深度大于3 km,断层核普遍发育有内聚力的断层角砾岩和碎裂岩,破碎带发育多种成因的裂缝。随着位移的增加,破裂模式从早期的破裂作用变为后期的碎裂作用,最终形成碎裂流。断裂带演化是一个四维过程,断层核和破碎带发育情况直接影响断层对油气的运移和封闭的作用。断裂变形机制、断裂带内部结构以及与流体运移关系的研究,都可为封闭性提供重要的理论依据。     

油源断裂输导和遮挡配置油气成藏有利部位预测方法及其应用

为了研究含油气盆地下生上储式油源断裂附近油气成藏规律,在油源断裂输导和遮挡配置油气运聚机制及有利部位研究的基础上,通过确定油源断裂伴生裂缝发育部位和储集油气砂体分布区,确定油源断裂输导油气有利部位;通过确定油源断裂侧向封油气部位和储集砂体分布区,确定油源断裂遮挡油气有利部位,二者结合建立了一套油源断裂输导和遮挡配置油气成藏有利部位的预测方法,并将其应用于渤海湾盆地歧口凹陷板桥断裂在始新统沙河街组一段下亚段(沙一下亚段)内输导和遮挡配置油气成藏有利部位的预测中,结果表明:板桥断裂在沙一下亚段内输导和遮挡配置油气成藏有利部位主要分布在其东北中部,少量分布在西南东部,有利于下伏始新统沙河街组三段(沙三段)源岩生成油气在沙一下亚段内运聚成藏,与目前板桥断裂附近沙一下亚段内已发现油气主要分布在其东北中部,少量分布在西南东部相吻合,表明该方法用于预测油源断裂输导和遮挡配置油气成藏有利部位是可行的。     

箕状断陷控洼断裂上下盘油气成藏差异性及勘探实践——以南海北部珠江口盆地惠州凹陷X洼为例

箕状断陷是中国东部陆架边缘盆地常见的洼陷样式,其陡坡带是有利的油气成藏区带之一。控洼边界断裂对于陡坡带油气成藏具有明显控制作用。断裂带内部结构导致下盘油气成藏模式不同于上盘。以珠江口盆地惠州凹陷X洼控洼边界断裂（X断裂）为例,分析认为其为一条长期继承性活动的大断层,发育完善的破碎带和断层核二元结构,并以此为基础分析了X断裂对下盘油气成藏的控制作用及其与上盘的差异。采用定性+定量的方法评价认为,X断裂发育连续的致密断层岩,在主要目的层具有良好的侧向封闭性;导致两盘成藏差异的是断层垂向封闭性。X断裂下盘油气成藏的运移方式异于上盘,由于断层核的遮挡,油气并不是直接充注圈闭,而是通过断层末端或者转换带的连通砂体以类似于螺旋楼梯式的方式运移至下盘。综合认为,X洼下盘断圈构造具有勘探潜力并得到了钻井证实。     

Representation of normal slant faults in a 2D burial history model

A discussion is given of the impact of normal slant faults on basinal structure, compaction, fluid overpressure development, and thermal effects in sedimentary basins. Faults which are hydraulically closed or open to fluid flow are examined in a dynamical two-dimensional fluid/ flow compaction model.
From this numerical investigation three dominant factors characterize the effects of single and multiple faults with open or closed hydraulic behaviours: (i) there is a difference in excess pressure for fault planes with open or shut hydraulic conditions, but the neighbourhood where the effect of the fault is dominant is fairly localized (to within about half a kilometre or so laterally from the fault plane); (ii) the lateral and vertical motion of sediments between faulted blocks induces a thermal difference prior to, during, and post-faulting, which can play a role in influencing hydrocarbon generation, migration, and accumulation; (iii) porosity retention and permeability modification by fault development could influence hydrocarbon exploration decisions regarding sealing, migration pathways, and fluid retention.
The general patterns of slant fault effects described here should prevail in most geological situations, because the numerical experiments are designed to illuminate sharply the dominant response characteristics within the framework of simplified situations.     

Fluid migration and origin of a mud volcano in the Northern Apennines (Italy): the role of deeply rooted normal faults

ABSTRACT In the foothills of the Northern Apennines mud volcanoes are locally aligned along active normal faults, which allow surface leakage of fluids derived from deep sources (>3–6 km). The chemical and isotopic analysis of the fluids of a mud volcano, coupled with the reconstruction of its geological setting, allowed an investigation of the processes of migration and fluid flow. The fault system associated with the Regnano mud volcano drains a deep Miocene reservoir (foredeep marine deposits), which supplies formation water and thermogenic methane that has migrated from underlying Mesozoic carbonates. The muds from the volcano contain late Eocene microfossils and are extruded only during paroxysmal events. They have a shallower origin (about 1 km) from the base of Tertiary marine deposits deposited upon the upper tectonic nappe of the chain (Ligurian unit). This case study suggests that normal faults are very effective in controlling surface emissions.     

塔里木盆地库车坳陷致密砂岩-膏泥岩储盖组合断裂带内部结构及与天然气成藏关系

本文在野外观察描述基础上,系统分析了库车坳陷致密砂岩-膏泥岩储盖组合内断裂变形机制,研究表明:断裂在膏泥岩内变形机制取决于埋藏深度决定的脆塑性,膏泥岩在浅埋条件下处于脆性变形阶段,形成断层泥充填的贯通型断裂,垂向封闭能力很差;膏泥岩在较深埋条件下处于脆-塑性变形阶段,形成涂抹型断裂带,伴随断距增加,涂抹逐渐失去连续性,连续的膏岩涂抹形成有效封闭,一旦失去连续性,油气将穿越盖层垂向散失;膏泥岩在深埋条件下处于塑性变形阶段,膏泥岩限制断裂穿层。因此,塑性膏泥岩和脆-塑性膏泥岩在涂抹连续情况下,能够形成有效封闭。断裂变形时储层已经致密化,抬升作用和储层超压导致断裂变形机制以破裂为主,断层核为断层角砾岩,破碎带发育大量裂缝,为油气垂向运移通道,侧向封闭依靠岩性对接。这种岩性对接封闭导致天然气聚集模式具有3个典型特征:一是天然气紧邻区域性盖层分布,即天然气层之上为区域性盖层;二是区域性盖层与储层对接形成有效封闭,因此天然气主要分布在气源断裂上升盘;三是烃柱高度取决于断距大小,圈闭范围内最小断距决定烃柱高度和气-水界面分布。     

Fault zone development and strain partitioning in an extensional strike-slip duplex: A case study from the Mesozoic Atacama fault system, Northern Chile

Upper crustal strike-slip duplexes provide an excellent opportunity to address the fundamental question of fault zone development and strain partitioning in an evolving system. Detailed field mapping of the Mesozoic Atacama fault system in the Coastal Cordillera of Northern Chile documents the progressive development of second- and third-order faults forming a duplex at a dilational jog between two overstepping master faults: the sinistral strike-slip, NNW-striking, Jorgillo and Bolfin faults. These are constituted by a meter-wide core of foliated S-C ultracataclasite and cataclasite, flanked by a damage zone of protocataclasite, splay faults and veins. Lateral separation of markers along master faults is on the order of a few kilometers. Second-order, NW-striking, oblique-slip subsidiary fault zones do not show foliated ultracataclasite; lateral sinistral separations are in the range of  10 to 200 m with a relatively minor normal dip-slip component. In turn, third-order, east–west striking normal faults exhibit centimetric displacement. Oblique-slip (sinistral–normal) fault zones located at the southern termination of the Bolfin fault form a well-developed imbricate fan structure. They exhibit a relatively simple architecture of extensional and extensional-shear fractures bound by low displacement shear fractures. Kinematic analysis of fault slip data from mesoscopic faults within the duplex area, document that the NW-striking and the EW-striking faults accommodate transtension and extension, respectively. Examination of master and subsidiary faults of the duplex indicates a strong correlation between total displacement and internal fault structure. Faults started from arrays of en echelon extensional/extensional-shear fractures that then coalesced into throughgoing strike-slip faults. Further displacement leads to the formation of discrete bands of cataclasite and ultracataclasite that take up a significant part of the total displacement. We interpret that the duplex formed by progressive linkage of horsetail-like structures at the southern tip of the Bolfin fault that joined splay faults coming from the Jorgillo and Coloso faults. The geometry and kinematics of faults is compared with that observed in analog models to gain an insight into the kinematic processes leading to complex strike-slip fault zones in the upper crust.