准噶尔盆地西部车排子凸起新近系沙湾组成藏体系与富集规律

准噶尔盆地西部车排子凸起远源成藏,新近系油气藏和油气显示基本都在一套厚砂层和其上的薄砂层中,厚砂层和薄砂层之间存在密切的油源联系。针对这一成藏现象,利用区域构造、油源对比、输导体系、化验证据、成藏特征等手段,系统研究车排子的成藏体系。结果表明,车排子轻质油源岩为侏罗系,主要来自昌吉凹陷西部,油气运移指向为东南到西北方向。区域构造运动形成的白垩系与侏罗系的不整合面和红车断裂的长期活动使得油气能从深部生烃区向浅层凸起区长距离运移。沙湾组一段区域展布的厚砂层高效的横向输导作用是车排子凸起油气规模富集的关键,喜马拉雅期小断层的纵向沟通促成了沙湾组二段薄砂岩性体的最终成藏。白垩系与侏罗系的不整合面-红车断裂-沙湾组一段厚砂层的紧密接触、良好匹配构成了复式、高效的输导格架。通过成藏体系研究,归纳总结了车排子地区的成藏模式,并提出沙湾组二段岩性油气藏和一段上倾尖灭或超覆油气藏是最有利的勘探方向。     

准噶尔盆地车排子周缘白垩系底部不整合面的形成及其油气输导作用

准噶尔盆地白垩系底部不整合面在车排子周缘大面积分布,是其二叠系和侏罗系的油源进入白垩系和新近系储层的重要通道之一,对其微观结构和几何形态的研究对油气勘探有重要意义。利用岩心、测井、岩屑录井等资料识别出不整合面的三层结构,对不整合面之上的岩石、风化粘土层及不整合面之下的半风化壳进行深入研究,探讨白垩系底部不整合面的形成过程,明确不整合面三层结构的油气输导作用。不整合面的形成可划分为抬升风化期、剥蚀搬运期、下降沉积期和成岩压实期4个阶段。研究表明风化粘土层上下的岩石具有高效的油气输导能力,风化粘土层在断裂不发育区可作为油气局部盖层。油气沿白垩系底部不整合面从东南向西北部的车排子凸起运移。     

车排子凸起南缘原油类型划分及油源分析

正车排子地区区域构造上位于准噶尔盆地西部隆起区,车排子凸起为隆起区主体,西北临近扎伊尔山,向南以斜坡形式逐渐过渡到四棵树凹陷,向东以红车断裂带与昌吉凹陷及中拐凸起相接,是形成于晚海西运动早期的一继承性的古隆起。车排子凸起构造条件良好,油源丰富,具备比较有利的油气聚集条件。以往研究表明,车排子地区古近系和新近系油源复杂,前人认为新近系原油与侏罗系烃源岩存在密切关系,但也存在较大争议,即其究竟是侏罗系和古近系油源的混源,     

鄂尔多斯盆地陇东地区三叠系延长组长3油层组石油运移与充注研究

鄂尔多斯盆地是我国第二大沉积盆地,中生界延长组富含丰富的油气资源。陇东地区位于鄂尔多斯盆地西南部,延长组长3段是该区重要的含油层系。在长3油层组原油特征和油源条件分析的基础上,对长3原油中含氮化合物组成和分布进行了探讨,结合成藏期分析,研究了鄂尔多斯盆地陇东地区长3油层组石油运移特征和注入方向。结果表明,长3油层组原油含氮化合物的分布与组成在纵向和横向上均存在明显的运移分馏效应,较好地指示了该区石油的运移。晚侏罗世至早白垩世,鄂尔多斯盆地延长组长7优质烃源岩进入生烃门限,并开始大量生烃,且以垂向、侧向、垂向-侧向交替式混合运移的方式,从盆地中心和生烃中心向西部和西南侧向运移和充注,油气充注点位于M18、Z71和Z49等井区周边区域。     

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。     

新疆焉耆盆地油气运移方向综合地球化学分析

分析了新疆焉耆盆地侏罗系原油的物性、含氮化合物含量和储层自生伊利石的同位素年龄在纵向和横向上的变化规律,探讨了焉耆盆地侏罗系油气运移方向。由上述分析可知,该区原油密度、含氮化合物含量和自生伊利石K-Ar年龄在平面上和垂向上均呈现出规律性的变化,即:平面上自南而北这些参数逐渐降低,垂向上同一构造带内随埋深减小这些参数逐渐变小。由此表明焉耆盆地侏罗系油气运移方向在平面上是从南向北,即油气先充注宝南储层,然后依次注入宝中和宝北储层;在纵向上是从深层向浅层运移,从八道湾组向三工河组和西山窑组储层中运移聚集。     

油气运移方向探讨——以南堡凹陷1号构造带为例

提要：利用原油中含氮化合物的组成和绝对浓度的变化并结合烃类生物标志化合物指标的研究,探讨了南堡凹陷1号构造带油气的运移特征。结果表明,原油中含氮化合物的分布和组成特征较好地指示了该区的油气运移效应。随着运移作用的加强,含氮化合物绝对浓度下降,“屏蔽”型与“暴露”型化合物的比值增加,油气沿着1号断层外侧的砂体,向构造的高部位运移。这与烃类生物标志化合物的成熟度参数变化所揭示的油气运移方向相一致,也与该区油气分布和勘探实践吻合较好。但两个参数间又存在区别,用生物标志化合物的组成和分布来指示油气运移分馏作用时,由于分馏作用较弱,各井间的数值变化较小。而含氮化合物的分馏作用较强,各参数随着运移距离的增加发生显著变化,且受成熟度的影响较小,更有利于油气运移方向的判别。     

准噶尔盆地西北缘车排子凸起原油类型与油源

准噶尔盆地西北缘南部红车断裂带- 车排子凸起油气藏众多,原油物理化学性质和地球化学特征十分复杂,原油类型及其来源长期存在很大争议。本文在准噶尔盆地不同时代烃源岩生成原油典型地球化学特征与主要油源判识指标归纳总结的基础上,对红车断裂带- 车排子凸起原油地球化学特征和来源进行系统分析研究,将该区域原油分为五类,其中三类原油分别来源于二叠系湖相烃源岩、中—下侏罗统煤系烃源岩、古近系安集海河组湖相烃源岩,另外两类为混合原油,分别为来源于二叠系湖相烃源岩的生物降解稠油与中—下侏罗统煤系烃源岩生成的正常原油和古近系湖相烃源岩生成的正常原油的混合原油。红车断裂带石炭系—白垩系油藏原油主要来源于沙湾凹陷二叠系湖相烃源岩,车排子凸起东北部春风油田稠油来源于沙湾凹陷二叠系湖相烃源岩;车排子凸起东侧- 红车断裂带西侧新近系沙湾组油藏轻质原油来源于四棵树凹陷古近系湖相烃源岩;车排子凸起中部春光油田白垩系—古近系油藏稠油为二叠系来源稠油和侏罗系正常原油的混合原油,新近系沙湾组油藏稠油为二叠系来源稠油与新近系正常原油的混合原油;车排子凸起西部石炭系—古近系油藏轻质原油来源于四棵树凹陷中—下侏罗统煤系烃源岩,而新近系沙湾组油藏轻质原油来源于四棵树凹陷古近系湖相烃源岩。本文对准噶尔盆地西北缘南部地区油气藏成藏研究及区域油气勘探决策具有重要参考作用。     

车排子凸起轻质油成熟度分析与烃源层再认识

通过对车排子凸起南部轻质油的甲基双金刚烷和甲基菲参数分析,发现其成熟度已达等效镜质组反射率约1.3％～1.6％的高过成熟阶段.结合周边凹陷烃源岩演化特征分析,认为该区轻质油来源于侏罗系烃源岩的可能性较小,来自二叠系高过成熟烃源岩的可能性较大.该区轻质油地球化学特征与二叠系烃源岩差异较大,而与白垩系和古近系烃源岩地球化学特征相似,推断该高过成熟油气中不含生物标志化合物或生物标志化合物含量极低,其现有特征是在运移过程中受成熟度较低而生物标志化合物含量丰富的烃源岩可溶有机质浸染所致.这一认识不但对揭示研究区的油气成藏规律具有重要的理论和实践意义,也将为准噶尔南部深凹区及山前坳陷区轻质原油及天然气来源的重新认识提供合理的参考依据.     

准噶尔盆地车排子凸起中生界油气包裹体定量分析及应用探讨

准噶尔盆地车排子凸起中生界砂岩储层中发育油气包裹体,在前人油源对比及成藏演化等研究基础上对油气包裹体特征镜下观察,采用数学统计学方法定量分析白垩系、侏罗系油气包裹体特点,对油气运移与成藏过程作初步探讨。研究表明:该地区中生界存在多源、多期充注特点,并首次厘定研究区水层GOI介于2.8%~4%,对该区油气水判识有指导意义。     

Tectonics and magmatism in eastern South America and the Brazil basin of the Atlantic in the Phanerozoic

The magmatic and tectonic activity of eastern South America and the western South Atlantic shows that extension of the continental crust is the determinant factor of magmatism. Heating of the upper mantle is a necessary condition of its manifestation. Ascending plume material is a source of additional heat. In the Early Mesozoic, Eastern Brazil was situated above a large, ascending and probably ramifying plume, which has supplied heat and material since the Triassic, creating favorable conditions for continental magmatism. Magmatic activity continued, gradually waning, until the Neogene as evidence for long-term retention of heat energy beneath the continental lithosphere after the plume ascent. It has been shown that heated mantle material can be displaced from the continent to the ocean for a significant distance beneath the lithosphere with the formation of linear tectonomagmatic rises of the oceanic crust. The structural elements inherited certain directions on the continent and in the ocean, beginning from the Neoproterozoic. These directions were reactivated and continued to control the younger structural grain and magmatic activity. In Southeastern Brazil, these were the structural units striking in the southeastern (about 120° SE) and northeastern directions parallel to the continent-ocean boundary. In Northeastern Brazil, the W-E- and N—S-trending structural units are predominant. All these directions are manifested in oceanic structural units (Rio Grande, Vitória-Trindadi, Fernando de Noronha, Pernambuco rises, etc.).     

Variations of the tree line and glaciers in the Central and Eastern Altai regions in the Holocene

Variations in the tree line position and glacier activity in the Central and Eastern Altai regions in the Holocene were reconstructed on the basis of analysis of sixty radiocarbon and eighteen dendrochronological dates. The tree line was higher than now in the Early and Middle Holocene, and the climate was warmer and, likely, more humid. Glaciers advanced in the forests 300, 1400, and 3000–6000 years ago. In the last millennium the forest decline at the upper tree limit occurred in 1206–1256, 1445–1501, and 1642–1736.     

Global repeating events in the history of the Earth and the motion of the Sun in the Galaxy

Chronological analyses of correlations between certain global repeating events (mass extinctions of marine organisms, meteorite impacts, and flashes in the frequency of geomagnetic reversals) during the Phanerozoic Eon and the motion of the solar system in the Galaxy are presented for five rotationally symmetrical models for the regular Galactic gravitational field. Thirteen of sixteen mass-extinction events can be described by a repetition interval of 183±3 million years. This is in agreement with the anomalistic period (interval between two subsequent passages of the Sun through the apocenter of its Galactic orbit) in the model of Allen and Martos. The positions of the minima and maxima in Gaussian functions approximating the frequency distribution for geomagnetic reversals also agree with the times of passage of the Sun through the apocenter and pericenter, respectively, of its Galactic orbit in this model. The maximum in the distribution of the deviations of the dates of mass extinctions from the nearest dates of impacts of large, crater-forming bodies is close to zero, providing evidence that many such events are correlated. As a rule, extinctions follow impact events. The impacts of large bodies have occurred most often when the solar system passes through the Galactic plane, while mass extinctions occur more often at some distance from the Galactic plane (about 40 pc). As a rule, intervals of increases in the frequency of geomagnetic reversals coincide with dates of impacts of large bodies. At the same time, these intervals do not show a clear correlation with the dates of mass extinctions. The intensity of mass extinctions, like the energy released by impacts, is consistently higher in periods when the Sun is moving from the apocenter toward the pericenter of its orbit, than when it is moving from the pericenter toward the apocenter. Thus, there is evidence for a variety of relationships between repeating global events in the Phanerozoic and the motion of the Sun in the Galaxy. Long-period variations in the frequency of geomagnetic reversals are correlated with the orbital motion of the Sun, and increases in the frequency of geomagnetic reversals are correlated with impacts. Mass extinctions are correlated with the impacts of large bodies, whose motions may have been perturbed by clouds of interstellar material concentrated toward the Galactic plane and by the shock front associated with the Perseus spiral arm, through which the solar system passes. The velocity of the Sun relative to the spiral pattern is estimated.     

我国中西部前陆盆地的特殊性和多样性及其天然气勘探

通过对我国中西部前陆盆地构造特征、大地构造背景、地球物理特征的理论研究和典型前陆盆地的详细解析,系统分析了我国中西部前陆盆地的发育特征和特殊性。强调晚二叠世以来大小不一、形态各异的多块体小型克拉通的聚合碰撞作用是导致中西部前陆盆地群形成的基本动力学过程：这些小型克拉通的多块体聚合碰撞造就了中西部前陆盆地的特殊性和多样性。同时,明确提出中西部盆地的基本特点是“两期三类前陆盆地”,即海西一印支期前陆盆地和喜山期前陆盆地,三类指海西一印支期的周缘前陆盆地和弧后前陆盆地、喜山期再生前陆盆地。根据前陆盆地的盆地结构和演化特征,又将中西部的前陆盆地划分为4种组合形式,即叠合型组合、改造型组合、早衰型组合和新生型组合。综合论述了不同时期不同类型前陆盆地构造对天然气聚集的五大控制作用。     

Phenanthrene biomarkers in the organic matter of Precambrian and Phanerozoic deposits and in the oils of the Siberian Platform

The composition and distribution of phenanthrenes (polyaromatic compounds) have been studied in chloroform extracts from dispersed organic matter (OM) of clayey, siliceous, carbonate, and terrigenous rocks of different ages and facies and from some oils of the Siberian Platform. Phenanthrenes have been analyzed by gas chromatography-mass spectrometry. High contents of 1,7,8-trimethylphenanthrene and 1,1,7,8-tetramethyl-1,2,3,4-tetrahydrophenanthrene are present in the OM of Vendian and Cambrian carbonate-shale deposits and in ancient oils of the Nepa-Botuobiya and Anabar anteclises. The OM of Permian continental deposits and oils of the Vilyui syneclise is dominated by 1-methyl-7-isopropylphenanthrene (retene). A triangular diagram for identification of the types of original OM of rocks and classification of genetically related oils has been constructed based on the assessment of phenanthrene biomarker distribution. Putative pathways of the formation of phenanthrene biomarkers are discussed.     

Diamond crystallization in the Fe-Co-S-C and Fe-Ni-S-C systems and the role of sulfide-metal melts in the genesis of diamond

Diamond crystals 0.1–0.8 carats were synthesized in experiments conducted in a BARS split-sphere multianvil high-pressure apparatus in the systems Fe-Co-S-C and Fe-Ni-S-C at a pressure of 5.5 GPa and temperature of 1300°C. The microtextures of the samples and the phases accompanying diamond (carbides, graphite, monoslufide solid solution, pentlandite, and taenite) are examined in much detail, the properties of metal-sulfide-carbon alloys are discussed, and issues related to the genesis of sulfide inclusions in diamonds and graphite crystallization in the diamond stability field are considered. The experiments demonstrate that diamonds can be synthesized and grow in pre-eutectic metal-sulfide melts with up to 14 wt % sulfur at relatively low P-T parameters, which correspond to the probable temperatures and pressures of natural diamond-forming processes at depths of approximately 150 km in the Earth’s upper mantle.     

微亮晶（臼齿）碳酸盐成因及其在元古宙地球演化中的意义

本文应用多种技术方法,对微亮晶碳酸盐岩的成岩作用及其成因从宏观至微观进行了分析。根据岩石矿物学、地球化学和有机地球化学等研究证明,它是早期成岩过程中,在超高压的大气 CO_2,水平急剧下降的转折期,快速石化作用形成的具等粒结构μm级的微亮晶方解石集合体。MT 碳酸盐岩微亮晶成岩作用有两种类型:一是主要发生在海底沉积软泥中,在其底基质软泥中经差异压实作用形成褶皱肠状及复杂形的 MT 构造;二是直接在海水中或重力流搬运过程中形成的微亮晶球粒(核)。简言之,MT 碳酸盐岩石是在地球早期浅海环境下,由于微生物自养作用形成的地球化学成因产物。微亮晶碳酸盐岩是约束古大气圈和古海洋环境变化的最灵敏标志。通过详测 MT 丰度值和编制地球古大气圈 CO_2水平演化模式等,在前寒武纪发现有太古宙末期、早元古宙末期、中元古宙中期和新元古宙早-中期四个 MT 碳酸盐岩发育高峰值期,证明全球古大气圈 CO_2水平发生过四次不连续性、跳跃式下降周期,直到晚新元古宙未,全球雪球事件的发生,导致了 MT 碳酸盐岩的消失。其后,才进入显生宙的 CO_2低水平状态。MT 碳酸盐岩具有重要的油气资源远景,应予以重视。     

中国参与北极油气资源开发利用前景与方向

北极地区丰富的油气资源近年来引发全世界的广泛关注。评估结果显示,北极油气资源分布不均,主要集中在俄罗斯、美国阿拉斯加、挪威、加拿大和丹麦格陵兰。不同国家和地区北极油气资源勘探开发特点不同,在新形势下可能还会发生变化。中国是油气消费大国和进口大国,俄罗斯北极地区已日渐成为中国重要油气供应地之一。综合分析几个主要北极国家北极油气开发利用现状和未来发展前景,与中国目前参与北极油气开发利用的情况,对未来中国如何参与北极油气资源开发利用提出建议,将俄罗斯作为中国北极油气开发的长期合作伙伴,与其开展项目投资、技术入股、航道建设等多个方面的合作。      

Progress in the study of the geography of retailing and wholesaling in Britain

Geographers have devoted a considerable amount of attention to the distributive sector. In part this has arisen because this sector provides an excellent testing ground for techniques. Substantive research, despite the needs of decision makers in both the public and private sectors, has been inbalanced. It has tended to focus on shoppers' behaviour and the factors controlling supply, at least equally important, have been relatively neglected. The paper indicates the significance of these factors and demonstrates how they need to be integrated into different modelling and theoretical approaches if research is to provide really useful insights for decision makers. It outlines how the focus of geographical study has shifted from examining the distributive trades as indicators of other facts of urban systems to the examination of spatial variations which are of substantial operational significance. Such studies do, however, fit readily into a wider frame-work of a geographical environment which is continuous but partitioned, limited but expanding and organised but diversified. Fruitful research can thus adopt both a spatial and an ecological perspective. The importance of the sector in the economy is sufficient reason for such research to be conducted.     

Silica and the cycle of carbon in the ocean

Silicon is a key element whose major role in the control of the cycle of carbon in the ocean has been recently revealed. This is first illustrated through the resolution of the ‘opal paradox’ in the modern Southern Ocean. Second, the ‘silica hypothesis’ explains why, during the Last Glacial Maximum, the atmospheric concentration of CO₂ was about 40 % below that of the interglacial period. Increased deliveries of wind-borne silica to the surface ocean as well as of riverine inputs favoured the dominance of diatoms over coccolithophorids, resulting in a net emission decrease of CO₂ by coccolithophorids from the ocean surface to the atmosphere. To cite this article: P. Tréguer, C. R. Geoscience 334 (2002) 3–11