Using Geochemical Method to Distinguish Lateral Migration and Vertical Migration in Rifted Basin: A Case Study from Eastern Lujiapu Depression in the Kailu Basin, NE China

Migration fractionation diagnosis is complicated in rifted basins where migration distance is generally short and lateral migration in sandy beds and vertical migration along faults are co-existed. Quantitative data from GC-MS analysis makes it possible to distinguish lateral and vertical migration effects. Oils discovered from the Jiaolige oilfield, eastern Lujiapu Depression are derived from single source rock with similar maturity, which is an ideal case to study the migration fractionation effects. Compositional differences among oils are largely caused by the migration fractionation either laterally in sand beds or vertically along the faults. Subtle maturity differences are assessed by the classic saturated hydrocarbon parameters which have certain influence on nitrogen compounds. In a certain maturity range, the ratios of shield and semi-shield isomers to the exposed isomers of alkylcarbazoles change with maturity in an opposite direction with migration fractionation, which may conceal the migration influence. However, migration and maturation have the same effects on absolute concentrations of aikylated carbazoles and benzocarhazole [a]/([a] [c]) ratios, which provides an ideal tool for migration direction assessment. Continuous variations among different samples reflect increased migration distance in sandy beds, while abrupt changes may indicate the change of migration conduit systems. Integrated both geochemical interpretation and geological constrains, not only migration direction can be determined, but also the conduit systems through the sandy beds or the. faults can be recognized.     

Applicability of Carbazole Migration Indices in Continental Rift Basins: A Case Study of Western Lujiapu Depression in Kailu Basin, NE China

<正>Kailu Basin in which the Western Lujiapu Depression is located is a typical continental rift basin.Biomarker parameters of the oils indicate that depositional facies and environments vary between the Bao 1 and Bao 14 fault blocks with a higher saline environment in the Bao 1 fault block, but such difference has no significant impact on carbazole abundance and distribution.Maturity and migration distance are the main controls on carbazole abundance and distribution in the Western Lujiapu Depression.The commonly used migration indices,such as ratios of nitrogen shield isomers to nitrogen exposed isomers(1-/4-methylcarbazole ratio,1,8-/2,4-dimethylcarbazole(DMC) ratio and half-shield/exposed-DMC ratio),absolute concentrations of alkylated carbazoles and BC ratio(=benzo [a]carbazole/(benzo[a]carbazole+benzo[c]carbazole)) increase at the low mature range and decrease at a higher mature range with increasing maturity.At relatively low maturity stage(Rc0.77%), maturation has reversal effects with migration on the ratios of nitrogen shield isomers to nitrogen exposed isomers,which may cover migration influence and makes these parameters fail to indicate migration effects.Valid migration indicators at this maturity stage are concentrations of alkylated carbazoles and BC ratios,which can provide ideal tools for migration direction assessment even within short migration distance.Maturity effects should be taken into account when carbazole compounds are applied to indicate migration direction,and at different maturity stages,these commonly used parameters have different validity in tracing migration direction.Coupled with our previous study in the Eastern Lujiapu Depression,a conceptual model of the variation of nitrogen migration indices can be established for terrestrial rifted basins,that is,strong fractionation lateral migration model through sandy beds,weak fractionation vertical migration model along faults,and maturity impacts on migration assessment.     

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.     

塔里木盆地塔中隆起奥陶系碳酸盐岩油气运聚主控因素及成藏模式

从多元地质条件及其空间匹配关系角度出发,综合地质剖析及地球化学示踪等方法,对塔里木盆地塔中隆起奥陶系油气输导体系、运移方向及分布特征等进行的精细研究。结果显示:断裂、源储接触关系及盖层等共同控制着油气垂向运移的距离及层位;构造背景、不整合面、渗透性输导层、断裂的配置关系等控制着油气侧向运移的方向、通道和距离;海平面升降旋回、优质储层的配置关系控制着油气垂向聚集层位及平面分布规律。进一步结合研究区烃源岩条件、储层类型等研究成果,基于源储纵向接触关系及油气垂向运移距离,目的层油气成藏模式可分为近源混合成藏模式与远源混合成藏模式;根据油气来源区域及油气横向运移距离,又可分为内部源岩叠加混合成藏模式与内外部源岩交叉混合成藏模式。     

油气倒灌运移形式分布区预测方法及其应用

为了研究含油气盆地倒灌运移油气分布规律,在油气倒灌运移和常规油气运移对比的基础上,对油气倒灌运移形成所需条件和分布区预测方法进行了研究,结果表明:油气倒灌运移按运移方向可分为油气垂向和侧向倒灌运移形式两种,前者发生所需条件是油源断裂发育在一定压力差的紧邻源储区内,后者发生所需的条件是油源断裂发育在区域性盖层封闭区内。通过一定压力差的紧邻源储区和油源断裂叠合和区域性盖层封闭区和油源断裂分布叠合,分别建立了一套油气垂向和侧向倒灌运移形式分布区的预测方法,并将其分别应用于松辽盆地三肇凹陷青一段源岩生成的油向扶扬油层垂向倒灌运移形式分布区和渤海湾盆地南堡凹陷沿油源断裂运移天然气向东一段储层侧向倒灌运移形式分布区的预测中,其结果表明:三肇凹陷青一段源岩生成的油向下伏扶扬油层垂向倒灌运移形式分布区,除凹陷内和边部局部地区外,整个凹陷分布,南堡凹陷沿油源断裂运移的天然气向东一段源岩侧向倒灌运移形式分布区主要分布在凹陷西南地区。分别与三肇凹陷扶扬油层目前已发现的油藏分布和南堡凹陷东一段目前已发现的气藏分布相吻合,表明该二种方法分别用于预测油气垂向和侧向倒灌运移形式分布区是可行的。     

超压盆地油气垂向运移高度研究

在超压盆地中,当断层活动断开超压烃源岩时,油气会沿断层面发生涌流式垂向运移,这一瞬态涌流过程为油气大规模运聚成藏提供了重要的油气来源。然而,对于油气沿断层垂向运移距离问题的研究,停留在定性分析阶段,较少考虑到断层开启时造成的泄压作用,也很少区分地层水和油气运移距离的差异。本文认为,油气顺断层向上运移的距离主要由源岩超压带内超压幅度决定,油气垂向运移理论高度可由超压幅度折算,因而超压幅度越大,油气垂向运移距离越远,油气上涌顶界面埋深越浅。油气初次上涌的起始位置不是地表面,而是有效烃源岩顶面。另外,由于油气的大量上涌,超压带快速泄压,大部分油气上涌实际距离不能达到理论上涌的最大距离。同时,考虑到沿断层运移时受到阻力作用,油气实际上垂向运移高度远远小于理论运移高度。     

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。     

松辽盆地滨北地区扶杨储层油气优势运移通道

松辽盆地滨北地区具有一定的油气资源潜力,但勘探方向和目标不明,亟需开展油气运移方向的研究。通过对滨北地区影响油气运移方向的地质因素的分析,确定了盖层底面构造形态、砂体、断裂及水动力4种主控因素。通过对每种主控因素与油气运移方向相互关系的系统分析,采用单因素叠加和多信息叠合的方法分别定性和定量地预测了滨北地区扶杨储层的油气优势运移通道。结果表明,滨北地区扶杨储层主要发育两个优势通道方向,分别为自三肇凹陷北端沿绥棱背斜带向东北方向和自克山-依龙背斜带南部向其东北方向。这两个优势运移通道方向所指示的区域是油气勘探的有利区域,而通道上的圈闭则是有利的勘探目标。     

Reservoir geochemistry of the Tazhong Oilfield in the Tarim Basin, China, Part II. Migration, accumulation and mixing of crude oils

Measurements of the absolute and relative concentrations of nitrogen-containing compounds in crude oils from different reservoir strata (Ordovician, Silurian and Carboniferous) in the Tazhong region of the Tarim Basin, Xinjiang, China, showed that even though there are quite a number of factors affecting the distributional and compositional characteristics of neutral nitrogen-containing compounds in crude oils, the distributional and compositional characteristics of crude oils whose source conditions are approximate to one another are influenced mainly by the migration and fractionation effects in the process of formation of oil reservoirs. In addition, crude oils in the Tazhong region show obvious migration-fractionation effects in the vertical direction. Carboniferous crude oils are characterized by high migration parameters and low compound concentrations, just in contrast to Ordovician crude oils. This indicates that crude oils from shallow-level oil reservoirs were derived from those of deep-level oil reservoirs via faults, unconformable contact or carrier beds. Crude oils from the Tazhong region show some migration-fractionation effects in the lateral direction, but mixing of crude oils derived from different hydrocarbon source rocks in the process of formation of oil reservoirs made it more complicated the migration and accumulation of crude oils, as well as the formation of oil reservoirs.     

Migration Fractionation of Neutral Nitrogen Compounds of Crude Oils from Tabei Oilfield in the Tarim Basin, China

The absolute amounts and relative distributions of neutral nitrogen compounds in the Tabei oilfield (e. G. Blocks Ln1-Ln1 1) showed remarkable migration fractionation in the vertical direction. From Ordovician reservoirs (O) to oil legs TⅢ and T Ⅰ of Triassic reservoirs in blocks LN1-LN11, the concentrations of [a] [c] decreased from 1. 59μg/g, 0.49μg/g to 0.17 μg/g (oil). The ratios of various alkylcarbazole isomers, such as 1,8-dimethylcarbazole/nitrogenpartially shielded isomers and 1,8-dimethylcarbazole/nitrogen-exposed isomers, were adopted as the indicators of petroleum migration. The ratios increased from 0.13, 0.20 to 0.67 and from going from the south to the north of the Tabei oilfield, the absolute concentrations of neutral nitrogen compounds decreased drastically, and the nitrogen-shielded isomers were enriched relative to nitrogen-exposed isomers and nitrogen-partially shielded isomers. Crude oils in the Tabei oilfield migrated laterally from the Jilake structure to the Sangtamu fault uplift and Lunnan fault uplift, and crude oils in the same fault uplift migrated and remigrated vertically from Ordovician reservoirs, to oil legs TⅢ to TⅠ of Triassic reservoirs.     

柴西南昆北断阶带油气运移特点

本文在分析昆北断阶带油气运移输导层基本特点的基础上,结合油气显示的分布特点分析,对昆北地区油气运移特点进行了分析和预测。基岩顶面不整合是昆北断阶带油气的主导输导层。受印支期的长期风化剥蚀,昆北地区普遍发育基岩风化壳,从而形成广泛的不整合输导层。不整合输导层由古近系底砾岩和基岩风化层两部分构成,在不同井区可表现出单通道或双通道等不同输导特点。从宏观上看,油气从昆北油源断层爬上昆北断阶带后主要通过不整合进行横向扩展运移,不整合输导层的构造形态导致油气优先沿不整合输导层的构造脊线进行优势运移,当遇到不封闭断层时,则发生沿断层面向上调节运移或顺沿断层面进行横向运移。昆北地区断层侧向封闭性普遍较强,而NNE、NE走向的断层垂向封闭性弱,成为调整油气向上或改向运移的重要通道。除底砾岩外,昆北地区古近系砂层输导油气的范围有限,只有与断层和基岩不整合输导层有接触的砂层才起到局部的输导作用。因此,昆北地区油气主要集中分布在基岩不整合和断层附近。     

准噶尔盆地车排子凸起沙湾组油藏输导体系研究

新近系沙湾组是准噶尔盆地车排子凸重要的油气富集层位。在对沙湾组油藏分布、油性进行分析的基础上,结合前 人研究成果,将沙湾组油气的成藏过程分为两个阶段：古油藏阶段和次生调整阶段,并分别论述各阶段的输导体系及其时 空组合关系。古油藏阶段主要发育白垩系底部不整合面和红车断裂带同生逆断层组成的输导体系,研究区北部的白垩系底 面不整合有效输导厚度大,向西逐渐减薄为0;同生逆断裂是控制红车断裂带发育演化的主干断裂,形成时间早,断距 大。次生调整阶段则发育有沙湾组一段底部砂体、红车断裂带后生正断层、艾卡断裂带、凸起之上新近系张性断裂组成的 输导体系,沙一段砂体在凸起之上分布广泛,沉积连续而稳定,呈“毯状”自南向北逐渐减薄,做为最底部的砂体层,是 该阶段主要的横向输导体系;新近纪末期红车断裂带发育了一期正断裂,断裂活动强度大且规模较大,凸起之上则发育一 期与红车断裂带后生正断层同期形成的新近系正断层,凸起南部四棵树凹陷的艾卡断裂活动期长、断距大、延伸远,这些 断层构成了次生调整阶段的纵向输导体系。利用运移通道指数（MPI） 及颗粒荧光定量分析（QGF） 分别预测了白垩系底 不整合面及沙一段毯状砂体的优势运移区。平面上将运移通道指数在0.3以上的区域作为不整合输导层的优势运移区,将 QGF指数值大于3.8的区域作为沙一段毯状砂体的优势运移区。通过分析多套输导体系在油气成藏的不同阶段的空间组合以 及油气分布与输导体系的关系,明确了输导体系对油气成藏的控制作用,预测609井区具备油气输导的有利条件,可作为 下步勘探目标区。     

鄂尔多斯盆地马岭油田延9油层组油气运移研究

我们首次对马岭油田延9油层组原油充注点和运移方向、期次、通道及动力进行了系统地研究。结果表明,马岭油田延9油层组原油中咔唑类化合物的运移分馏效应明显,不同地区原油样品中咔唑类化合物异构体分布特征反映了延9原油具有3个充注点,运移方向为向南东方向和向北西方向运移;纵向上是由下向上,即从延10以下层位向上运移的方向。油藏储层包裹体均一化温度分布呈现出两个主峰温度,说明油气经历了两次运移期和充注期。研究资料显示马岭油田延9油层组原油运移通道在纵向上主要是河道深切谷和延9与延10油层组河道砂体的相互纵向叠置直接接触部位,或者是延10油层组泥岩很薄处形成的油气运移窗口;横向上为联通的多分支河道。油气运移的纵向动力主要为毛细管力和剩余压力。该研究成果对鄂尔多斯盆地侏罗系油气的进一步勘探和开发具有一定的指导意义。     

Research on the direction of secondary migration of oil by making use of nitrogen compounds as tracers in the No. 6 area of the Melut Basin

1 IntroductionThe application of isomeric-nitrogen compounds astracers to oil-migration research is a piece of innovatorywork, and also a newbreakthrough made in non-hydro-carbon geochemistry research. At present, a lot ofwork has been done on nitrogen co…     

塔里木盆地石油运移的孢粉学证据

基于塔里木盆地塔北、库车、喀什和叶城四个含油气区 44个原油样品和 3个天然气样品中发现的化石孢子花粉89属183种的研究, 在该盆地地质背景下探讨了石油运移的机理。研究内容包括石油运移的通道、相态、方向、路线和期次。研究结果表明, 在油气源岩成岩过程中由异常高压形成的微裂隙是石油初次运移的通道 断层、不整合面、节理和其他裂隙是石油二次运移的通道 在运移过程中石油可保持其原有相态, 液态与气态混合相是塔里木盆地石油运移过程中的主要相态 石油运移的方向因油藏类型而异, 或以垂直运移为主, 或以侧向运移为主。     

马朗凹陷断裂-烃源岩空间配置关系与石油垂向运移特征

马朗凹陷的原油类型可以划分为3大类,Ⅰ类原油来自二叠系芦草沟组,Ⅱ类原油来自石炭系哈尔加乌组,Ⅲ类原油为Ⅰ与Ⅱ类原油的混源油。通过断裂活动强度、垂向输导断裂与烃源岩的匹配关系的研究,结合原油含氮化合物的分析资料,分析了马朗凹陷油气的垂向运移特征。研究表明,断层的断裂活动强度控制着油气的垂向运移能力,垂向输导断裂与烃源岩相匹配时,烃源岩生成的油气才能向上运移至上覆地层聚集成藏。二叠系芦草沟组烃源岩厚度中心附近的垂向输导断裂断穿侏罗系,所以,芦草沟组烃源岩生成的Ⅰ类原油可以运移至侏罗系聚集成藏,而石炭系哈尔加乌组烃源岩附近的断裂大都未断至二叠系和侏罗系,所以哈尔加乌组烃源岩生成的Ⅱ类原油未能运移到侏罗系聚集成藏,而主要在石炭系成藏。与断裂输导分析相配合,含氮化合物可以很好示踪油气的垂向运移方向,沿断裂从深层到浅层,原油含氮化合物总浓度逐渐降低,1,8DMC/1,3 DMC或1,8DMC/2,4 DMC值增大。     

塔里木盆地巴楚地区油气运移的控制因素分析

影响巴楚地区油气运移的因素有断裂、不整合面及输导层.断裂是油气进行垂向运移的主要通道,而不整合面和输导层是油气进行侧向运移的主要通道.断裂的3次形成期为加里东期、华力西晚期和喜山期.后两期断裂规模较大、组合样式以背冲式为主,对油气的垂向运移、聚集成藏起到重要作用.3期较大的不整合面有T74界面、T70界面和T60界面.不整合面与上下地层之间存在3种接触关系:平行接触、削截接触和超覆接触,其中超覆接触关系具有最强大的输导能力.输导层有石炭系和志留系底部的连通砂体及下奥陶统顶部的岩溶.巴楚地区3次构造运动决定3次油气成藏,华力西晚期和喜山期的构造运动对加里东期形成的油气藏进行调整形成现今的油气分布格局.     

准噶尔盆地中部Ⅰ区块现今油气运移方向研究

根据石油成熟度梯度、原油中吡咯类含氮化合物丰度和异构体参数变化特征以及原油中高分子量正构烷烃的分布特征,结合车—莫古隆起的构造演化,探讨了准噶尔盆地中部Ⅰ区块油藏可能的油气运移方向。结果表明,研究区原油间运移分馏效应十分复杂,近期原油主要运移方向是由南向北,即油气是从南部的征1井区向沙1井、庄1井区运移。     

埕北断坡区断层对油气成藏的控制作用

根据埕北断坡区三维地震资料,探讨了主要断层的构造特征;依据石油运移地球化学资料和油气分布特征,研究了主要断层对油气运移的控制作用.结果表明,研究区油气以沿断层垂向运移方式为主,以侧向运移为辅,该区油气藏类型多与断层有关,主要圈闭类型为断块和断鼻型.据此建立了油气沿断裂运移的模式,并预测了有利的油气聚集区域.认为歧东断层...     

川东北飞仙关组鲕滩气藏天然气运聚效率

设计进行了封闭体系下原油裂解成气的模拟实验, 建立并标定了原油裂解成气及其碳同位素分馏的化学动力学模型, 以罗家寨气田罗家7井为例分别进行了地质应用.生烃动力学研究发现, 飞仙关组古油藏具备“高效气源灶”的特点, 原油在中晚侏罗世172~151Ma约20Ma时期内裂解殆尽, 且原油裂解气的生成与其运聚成藏作用具有良好的时空匹配关系, 由此可促成飞仙关组气藏天然气的高效运聚.碳同位素分馏动力学研究证实甲烷成藏参与率达87%.利用生烃动力学与碳同位素分馏动力学结合的方法对天然气的运聚效率进行探讨是一个新的有效途径.