古地貌对生物碎屑灰岩沉积成岩的控制作用

<正>X油田位于伊拉克东南部,是以生物碎屑灰岩为主的巨型油田,主力产层为白垩系M组下段MB2—MC1油藏,也是滩相沉积最为发育的层段。相比于碎屑岩,碳酸盐岩储层发育控制因素更为复杂,包括海平面升降、生物生活习性及古地貌特征等,研究难度更大(杜相仪等,2021)。特别是中东生物碎屑灰岩,受限于资料限制,古地貌相关研究较为缺乏,其对沉积特征和差异成岩的控制作用研究较少涉及（Assadi et al., 2023）。本文基于地震、测井、     

生物碎屑灰岩差异成岩及储集层特征:以伊拉克HF油田白垩系Mishirif组为例*

中东地区白垩系Mishirif组以生物碎屑灰岩为主,其形成于温暖潮湿的环境中。综合利用岩心、铸体薄片、全岩分析、常规物性及高压压汞等资料,以伊拉克HF油田Mishrif组为例,开展生物碎屑类型、分布特征、差异成岩及储集层特征等研究。Mishrif组灰岩中生物碎屑以底栖有孔虫、非固着类双壳类、厚壳蛤和棘皮动物为主,含少量苔藓动物、藻类与海绵动物,其含量、类型及大小对沉积环境有重要指示意义。沉积环境决定岩石组分与结构的差异,在此基础上成岩作用控制岩石的孔隙结构与物性特征。生物碎屑主要经历了不同程度海水环境的泥晶化和生物钻孔、大气淡水环境的溶蚀和胶结、埋藏环境的压实压溶和颗粒破裂作用。以底栖有孔虫和非固着类双壳类碎屑为主的低能沉积环境具有“弱溶蚀、强胶结、强压实”的成岩特征,主要发育微孔、晶间孔及粒内孔,孔喉分布呈偏细态细微喉单峰型,物性较差;以厚壳蛤和棘皮动物碎屑为主的高能沉积环境具有“强溶蚀、弱胶结”的成岩特征,主要发育铸模孔、粒间孔及粒间溶孔,孔喉分布呈偏粗态中粗喉极宽峰型,是Mishrif组最有利储集层。以HF油田Mishrif组为代表的白垩系生物碎屑灰岩在中东地区发育广泛,故上述成果对于该地区生物碎屑灰岩油气开发具有重要意义。     

灰岩-泥灰岩韵律层的差异成岩作用

灰岩-泥灰岩韵律层包括结核状灰岩到灰岩和泥灰岩互层,广泛分布在陆棚及深海环境中,出现于各地质时期,是研究高分辨率地层学和环境恢复的理想工具.但是成岩作用在灰岩-泥灰岩韵律层形成过程中的作用一直存在分歧,有的学者认为差异化学压实成岩作用加强了原始沉积的差异,有的学者认为成岩作用不仅能够强烈歪曲原始环境特征,还可以通过自身...     

泥晶灰岩的成岩作用与微孔隙研究

本文用岩石学方法结合超微技术及现代测试手段研究泥晶灰碉的成岩作用微孔隙。结果表明，对泥晶灰岩微孔隙形成有得的主要成岩作用为压溶、溶解和一定程度的云化及去云化、硅和去硅化作用。这些作用可以扩大微孔主微裂隙，使之有可能具有储集性能。     

层序地层级次对生物碎屑灰岩沉积演化的控制作用——以中东X油田Mishrif组中下段为例

以中东X油田Mishrif组中下段为例,综合利用地震、测井、岩心、铸体薄片及常规物性等资料,开展层序地层级次识别及层序地层级次对沉积演化的控制作用研究。结果表明：(1)Mishrif组发育5个三级层序和10个四级层序,中下段MB2—MC1层段对应三级层序SQ2—SQ3,包括4个四级层序,其内部发育11个五级层序和多个六级层序。(2)研究区发育次盆地碳酸盐开阔台地-弱镶边台地沉积,储层主要发育于台内滩和台缘滩中,按照生物碎屑类型可将滩相进一步细分为5种类型。(3)六级层序控制单滩体的沉积序列,五级层序控制多滩体的组合特征,四级层序决定沉积微相演化特征,三级层序决定沉积体系的演化特征。(4)SQ2层序的PSS3、PSS4四级层序早期为斜坡环境,发育透镜状滑塌粗粒沉积,后期发育台地边缘滩间→中能滩相沉积序列;SQ3层序的PSS5、PSS6四级层序发育台地边缘滩间→中能滩相→高能滩相沉积序列。SQ3沉积结束后形成了特殊的下切谷充填沉积。     

伊拉克H油田Mishrif组生物碎屑类型及对储层物性的控制作用

正白垩系Mishrif组生物碎屑灰岩是伊拉克H油田的重要产层,生物碎屑主要是有壳类碎屑(田泽普等,2016;王昱翔等,2017)。由于缺乏各类生物碎屑成分及成岩过程中的差异性分析,对生物碎屑灰岩储层物性的控制机理研究不够深入,限制了对该类储层的认识及高效开发。本文基于岩心观察、铸体薄片及常规物性等资料,开展伊拉克H油田Mishrif组的生物碎屑类型、成岩特征及储层物     

沉积成岩作用研究的若干问题

20世纪60年代由于物理化学动力学的引入和低温低压下矿物相平衡的研究,沉积成岩作用的研究有了突破性的进展,有机地球化学大大促进了沉积成岩作用的研究。现在沉积成岩作用的研究已经成为包括大地构造、盆地分析、沉积学、物理化学、有机地球化学等学科、范围包括大、中、小尺度的各种作用的综合研究。对油气和固体矿产资源的需求促进了沉积成岩作用的深入研究,石油天然气的形成和聚集、储层性质的变化涉及沉积成岩的全过程;一些低温低压的层控固体矿产的富集涉及盆地沉积充填、盆山转化的岩相及流体的动力和物理化学行为,自上世纪70年代以来,研究工作都有重要进展。近年来有关海洋沉积的研究、硅、锰、碳酸盐等沉积物形成、大地构造背景、同位素、有机物形成演化等的成岩过程的研究都有重要进展,也成为研究的热点问题。     

古地貌对渤海石臼坨凸起古近系沉积体系的控制作用

渤海湾盆地石臼坨凸起沙一、二段所发育的扇三角洲储层,在沉积演化过程中由于古地貌特征的不同,造成储集砂体形态特征及分布规律的不同,储层认识困难。通过分析断裂活动对古地貌格局的控制作用进行古地貌恢复,研究不同地貌单元与沉积体系的匹配关系,阐明了古地貌对沉积体系发育类型和沉积特征的控制作用,揭示了扇三角洲的沉积过程。在此基础上结合地震属性分析技术,精细描述了各沉积期次扇体的展布特征,并对沉积演化过程中扇三角洲沉积体系发育的差异性进行了解析。最终明确了盆地边缘沟谷和古地形发育特征对物源的控制作用,形成了"大沟对大扇,小沟对小扇"的沉积模式指导依据;同时确定了斜坡带上扇三角洲的沉积规律和砂体分布的控制机理。     

塔西南坳陷碎屑储集岩成岩环境及成岩作用类型

碎屑储集岩的成岩环境是控制成岩作用类型的主要因素。根据有机质演化特征、古地温和孔隙介质的酸碱性特征,可将其划分为酸性和碱性两种成岩环境。酸性成岩环境主要分布在早成岩阶段Ａ、Ｂ期和晚成岩阶段Ａ期,古地温＜９０℃,镜煤反射率ＲＯ值在０．５％～１．３％,其所控制的成岩作用包括压实、压溶作用,胶结作用和溶解作用。碱性成岩环境主要分布在晚成岩阶段Ｂ期以后,这时古地温达到９０℃以上,ＲＯ为１．３％～２％,主要成岩作用类型包括强烈的晚期含铁碳酸岩交代作用、自生伊利石和自生绿泥石沉淀作用、陆源伊利石重结晶成绢云母、高岭石向伊利石或绿泥石转变以及构造应力作用等。不同成岩环境中由于成岩作用组合特征的不同,导致碎屑储集岩的结构和孔隙组合特征上的差异,从而影响了储层的储集性能     

柳江盆地竹叶状灰岩岩石特征及沉积环境分析

河北柳江盆地寒武纪碳酸盐岩地层中发育有大量的竹叶状灰岩.本次研究从柳江盆地寒武系野外剖面及相关室内研究为出发点,把该地区竹叶状灰岩划分为四种类型,分别为无氧化圈无定向排列的猪肝色竹叶状灰岩、无氧化圈有微定向的紫红色竹叶状灰岩、带氧化圈紫红色的竹叶状灰岩以及灰色有分选有磨圆的竹叶状灰岩.分别反映了研究区不同时期的水动力条...     

Fluid inclusions in sedimentary and diagenetic systems

Some of the major problems in sedimentary geology can be solved by using fluid inclusions in sedimentary and diagenetic minerals. Important fluids in the sedimentary realm include atmospheric gases, fresh water of meteoric origin, lake water, seawater, mixed water, evaporated water, formation waters deep in basins, oil, and natural gas. Preserving a record of the distribution and composition of these fluids from the past should contribute significantly to studies of paleoclimate and global-change research, is essential for improving understanding of diagenetic systems, and provides useful information in petroleum geology. Applications of fluid inclusions to sedimentary systems are not without their complexities. Some fluid inclusions exposed to natural conditions of increasing temperature may be altered by thermal reequilibration, which results in stretching, or leakage and refilling, of some fluid inclusions. Similarly, overheating in the laboratory can also cause reequilibration of fluid inclusions, so fluid inclusions from the sedimentary realm must be handled carefully and protected from overheating. Natural overheating of fluid inclusions must be evaluated through analysis of the most finely discriminated events of fluid inclusion entrapment, fluid inclusion assemblages (FIA). Consistency in homogenization temperatures within a fluid inclusion assemblage, consisting of variably sized and shaped inclusions, is the hallmark of a data set that has not been altered through thermal reequilibration. In contrast, fluid inclusion assemblages yielding variable data may have been altered through thermal reequilibration. If a fluid inclusion assemblage has not been altered by thermal reequilibration, its fluid inclusions may be useful as geothermometers for low- and high-temperature systems, or useful as geobarometers applicable throughout the sedimentary realm. If a fluid inclusion assemblage has been altered partially by thermal reequilibration, techniques for distinguishing between altered and unaltered fluid inclusions may be applied.

In studies of global change, fluid inclusions can be used as sensitive indicators of paleotemperature of surface environments. Fluid inclusions also preserve microsamples of ancient seawater and atmosphere, the analysis of which could figure prominently into discussions of past changes in chemistry of the atmosphere and oceans. In petroleum geology, fluid inclusions have proven to be useful indicators of migration pathways of hydrocarbons; they can delineate the evolution of the chemistry of hydrocarbons; and they remain important in understanding the thermal history of basins and relating fluid migration events to evolution of reservoir systems. In studies of diagenesis, fluid inclusions can be the most definitive record. Most diagenetic systems are closely linked to temperature and salinity of the fluid. Thus, fluid inclusions are sensitive indicators of diagenetic environments.     

论沉积盆地内成岩相系划分及类型

沉积盆地内成岩作用和成岩相系划分研究,不仅有助于提升对沉积盆地内金属矿产、非金属矿产、能源矿产(石油、天然气、煤和铀矿)等同盆共存富集与协同成岩成矿成藏作用等方面的研究水平,也有助于提升对沉积盆地形成演化历史、盆山和盆山原耦合转换等大陆动力学过程的深入研究。将沉积盆地内成岩作用和成岩相系划分与地球化学岩相学识别技术紧密结合,采用构造岩相学与地球化学岩相学研究思路和方法,以成岩事件序列为主线,将沉积盆地内成岩相系划分为：①成盆期埋深压实物理-化学成岩作用和成岩相系;②盆地改造期构造-热事件成岩作用与构造热事件改造成岩相系;③盆内岩浆叠加期构造-岩浆-热事件成岩作用和岩浆叠加成岩相系;④盆地表生变化期表生成岩作用和表生成岩相系。从地球化学岩相学成岩机理上,对成岩相系的成岩环境和成岩机理进行识别,促进非金属矿产、金属矿产-油气资源-煤-铀等同盆共存与协同富集成矿成藏机理研究和深部矿产资源预测。     

A model of the diagenetic evolution of coaly sedimentary organic matter

Elemental composition was used to calculate the amounts of compounds produced during the diagenetic evolution of a coal series from the Mahakam delta (Kalimantan, Indonesia). These calculations were based on the following hypotheses: organic nitrogen does not take part in reactions and remains unchanged in the residual organic matter, the only compounds produced are water, carbon dioxide and hydrocarbons.This approach shows that carbon loss during diagenesis is mainly as CO₂, and hydrogen loss is mainly as H₂O. Hydrocarbon production is negligible, in accordance with absence of bacterial methane accumulations in the Mahakam delta.The δ¹³C of coals in the sequence becomes about 2 per mil more positive over the diagenetic depth range of coal evolution. Accounting for the coal δ¹³C change in terms of CO₂ loss requires that the CO₂ given off have δ¹³C of about ?40%.. Such negative CO₂ has not been observed in natural systems, except when CH₄ is undergoing oxidation. Several plausible causes for this effect are discussed.     

Taphonomic expressions of sedimentary hiatuses: field observations on bioclastic concentrations and sequence anatomy in low,moderate and high subsidence settings

Field studies of post-Palaeozoic siliciclastic records reveal a strong concordance between different types of bioclastic concentrations and discontinuity surfaces within third-order sequences ( 1 My duration), supporting the use of taphonomic criteria in establishing the relative magnitudes of sedimentary hiatuses. Comparison of records across a spectrum of subsidence rates, however (from 10 m to > 1 km/My), shows that, along with appreciable changes in sequence anatomy, the nature of surface-mantling bioclastic concentrations also changes. The most significant surfaces (second- and third-order sequence boundaries, surfaces or intervals of maximum transgression, transgressive surfaces) tend to be either bare or mantled with taphonomically complex hiatal and lag concentrations. These were more consistently encountered in low subsidence than in moderate subsidence records. In high subsidence records, major surfaces were more often mantled by composite or event concentrations, if they were bioclastic at all. In all subsidence settings, comparatively minor surfaces (parasequence boundaries, bed set boundaries and bedding planes) were bare or mantled with relatively simple event and composite concentrations. Although all fossil assemblages are biased taphonomically to some degree, relative degrees of bias should almost certainly vary among discontinuities as a general rule, suggesting specific adjustments in sampling strategies for evolutionary studies.     

蒙古国塔木察格盆地塔南凹陷早白垩世构造古地貌控砂机制*

构造活动是源-汇系统中形成古地貌和砂分散体系的重要影响因素。塔木察格盆地塔南凹陷在早白垩世是一个典型的断陷湖盆,经历了多期幕式断陷活动,但同沉积构造活动及其配置所产生的古地貌对层序结构特征、沉积体系及砂体分布的控制作用仍不明确。文中以地震、测井、岩心资料为基础,以层序地层学理论和古地貌控砂理论为指导,建立了塔南凹陷下白垩统层序地层格架;结合断层活动性分析,阐明了不同类型古地貌对沉积体系和砂体分布的控制作用和规律。构造演化和沉积充填的综合研究表明: 受控盆主断裂的幕式断陷活动及同沉积断裂的差异断陷活动影响,塔南凹陷发育横向凸起和走向斜坡2种类型的构造调节带,这些构造调节带是水系入盆的通道,控制着盆地的主体物源方向、沉积体系类型与分布特征;根据断层的几何形态及发育部位,共识别出4种类型构造坡折带,分别是陡坡断崖型坡折带、陡坡断阶型坡折带、缓坡反向断阶型坡折带和盆内坡折带,它们各自控制了不同类型沉积体系的形成与分布;沉积物入盆后,沉积物分散体系和砂体的分布特征受同沉积断裂的组合样式控制,研究区共发育梳状断裂系、叉状断裂系和平行断裂系3种同沉积断裂平面组合;与构造调节带相对应的断裂坡折带低部位是大型储层砂体,特别是低位扇三角洲或盆底扇砂体发育的有利部位,是寻找砂岩油气藏的有利区带。研究成果对于深化断陷湖盆源-汇系统理论、指导断陷湖盆砂体分布预测具有重要的理论意义和实际价值。     

石灰岩声发射特性的试验研究

采用SYB-4声发射仪和岩石声发射参数动态测试系统,对广西高峰石灰岩进行了单轴压缩条件下的声发射试验,研究了石灰岩在单轴加载过程中声发射活动随时间和岩样应力、变形等变化的内在规律,在此基础上分析了石灰岩的破坏机理。试验研究表明:除加载初期外,石灰岩声发射活动与试样体积变形间有较好的关联性,岩样中微裂纹形成和原有裂纹扩展是造成岩石声发射活动与体积变化的主要原因。因此,采用声发射技术可对矿山采场矿岩体变形稳定性进行监测和评价。     

The role of diagenetic carbonate concretions in the preservation of the original sedimentary record

The Upper Cretaceous organic rich limestones and marls of the Tarfaya basin of southwest Morocco contain numerous calcite concretions, which formed during early diagenesis. Relative textural similarities are observed both in the concretions and in the host sediments. However, the biological content of the concretions is considerably higher than in the host marls and limestones. Evidence for fossil dissolution in the host marls, and the absence of concretions in some fossil-rich zones, suggest that the difference in fossil abundance between the concretions and host rock is a function of dissolution, rather than preferential precipitation in fossil-rich areas. Consequently, the carbonate concretions appear to represent the 'memory' of the sediment and allow quantification of the original biological components and are potential tools for estimating the original biological material deposited in the soft sediments.     

石灰岩高速滚动摩擦特性

滑面的摩擦特性是高速岩质滑坡动力学研究的关键问题之一。以典型脆性灰岩为研究对象,借助滚动磨损试验设备,开展不同压力和转速条件下干燥和湿润灰岩的滚动摩擦试验,研究岩石动态摩擦特性（摩擦系数和磨损率）。试验结果表明,干燥和湿润岩石的滚动摩擦系数分别与摩擦速率呈负相关和正相关,与法向压力关系不明显。对于干燥灰岩,滚动试件（滑体）和静止试件（滑床）的磨损率与摩擦速率分别呈正相关和负相关。对于湿润灰岩,磨损率与摩擦速率呈正相关。基于Hertz弹性接触理论,推导出摩擦斑处的最大压应力和拉应力,进而提出相应条件下脆性灰岩的摩擦碎裂机制。结论可为灰岩高速滑坡防灾减灾提供设计参数。