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1.
Structures of the Bohai Petroliferous Area, Bohai Bay Basin   总被引：3，自引：0，他引：3  
This paper, for the first time, deals with a more systematic study of the structures in the Bohaipetroliferous area that covers nearly one third of the Bohai Bay basin. The study mainly involves the effects of preexisting basement faults on the basin formation, the characteristics of basin geometry and kinetics, the modelling of the tectonic-thermal history, the polycyclicity and heterogeneity in the structural evolution and the natural seismic tomographic images of the crust and upper mantle. The authors analyze the features of the dynamic evolution of the basin in the paper and point out that the basin in the Bohai petroliferous area is an extensional pull-apart basin.  相似文献   

2.
The Paleogene and Neogene oil and gas in the western Qaidam basin have a regular distribution in three concentric zones from the edge to the center of the basin.Natural gas mainly occurs in the inner zone,and the gas-oil ratio of the northern area of the basin is significantly higher than that of the southern area.Large amounts of carbon isotope data of natural gas,plotted in Xshaped and comprehensive identification diagrams for the southern area and northern area,respectively,were used to identify the types of natural gas.The large-scale distribution of natural gas is highly consistent with the Ro values of major source rocks,but is poorly correlated with the type of organic matter.This indicates that the main controlling factor of natural gas distribution is organic matter maturity,and the kerogen types act as the basis for the formation of different types of natural gas.Paleouplifts and squeezed anticlines near hydrocarbon generation depression centers,which are major natural gas-rich regions,control the migration directions of natural gas,while hydrocarbon migration pathways and fault systems connecting gas sources are the most important factors for natural gas reservoir formation in the inner basin.Therefore,favorable zones for natural gas distribution can be predicted on the basis of the distribution of thermal evolution and the gas generation intensity of major source rocks as well as the structural map.The Shizigou-YoushashanYingdong-Dawusi,Youquanzi –Kaitemilike- Youdunzi,and Xiaoliangshan – Nanyishan- Dafengshan structural belts are favorable zones for natural gas accumulation.This study has important theoretical and practical significance for future natural gas exploration.  相似文献   

3.
The origin and distribution of formation overpressure have effect not only on hydrocarbon migration and accumulation, but also on technique of drilling well. The study and prediction of overpressure are very important in basin analysis. At present, overpressure is mostly predicted by stack velocity.The process in calculating inter-velocity from stack velocity is very complex and inevitably leads to errors. Especially, this method is not available in the case that structural compression contribution to overpressure occurred. This paper introduces a new method, impedance inversion, to predict overpressure,and the principle is discussed. This method is used to predict the overpressure in Kuqa depression, Tarim basin and as a result, the absolute errors are less than 0.1, and relative errors are less than 5％ for predicted fluid pressure coefficients to the drill stem test (DST) measurements. It suggests that this method can be widely used to predict overpressure in foreland basins.  相似文献   

4.
The Songliao basin is a complex successor basin that was initiated in the Mesozoic and experienced multiple periods of reactivation. Based on seismic and drilling data, as well as regional geologic research, we suggest that the Songliao basin contains several different successor basins resting on top of Carboniferous-Permian folded strata forming the basement to the Songliao basin. These basins include the Triassic-Mid Jurassic Paleo-foreland basin, the Late Jurassic-Early Cretaceous downfaulted basin, and an early Cretaceous depressed basin （since the Denglouku Group）. This paper presents a systematic study of the basin-mountain interactions, and reveals that there are different types of prototype basin at different geologic times. These prototype basins sequentially superimposed and formed the large Songliao basin. Discovery of the Triassic-early Middle Jurassic paleo-foreland basin fills a Triassic-early Middle Jurassic gap in the geologic history of the Songliao basin. The paleo- foreland basin, downfaulted basin, and depressed thermal subsidence basin all together represent the whole Mesozoic-Cenozoic geologic history and deformation of the Songliao basin. Discovery of the Triassic-early Middle Jurassic paleo-foreland basin plays an important role both for deep natural gas exploration and the study of basin-mountain coupling in north China and eastern China in general. This example gives dramatic evidence that we should give much more attention to the polyphase tectonic evolution of related basins for the next phase of exploration and study.  相似文献   

5.
On the basis of reprocessing 34 new two-dimensional spliced long sections(20,191 km) in the Tarim Basin, the deep structure features of the Tarim Basin were analyzed through interpreting 30,451 km of two-dimensional seismic data and compiling basic maps. Seismic interpretation and geological analysis conclude that the Nanhua-Sinian strata are a set of rift-depression depositional systems according to their tectonic and depositional features. The rift valley formed in the Nanhua Period, and the transformation became weaker during the late Sinian Period, which eventually turned into depression. From bottom to top, the deposited strata include mafic igneous, tillite, mudstone, and dolomite. Three major depocenters developed inside this basin during the rift stage and are distributed in the eastern Tarim Basin, the Awati area, and the southwestern Tarim Basin. Among them, the rift in the eastern Tarim Basin strikes in the near east-west direction on the plane and coincides with the aeromagnetic anomaly belt. This represents a strong magnetic zone formed by upwelling basic volcanic rock along high, steep normal faults of the Nanhua Period. Controlled by the tectonic background, two types of sedimentary systems were developed in the rift stage and depression stage, showing two types of sequence features in the Sinian depositional stage. The Nanhua System appears as a wedge-shaped formation, with its bottom in unconformable contact with the base. The rifting event has a strong influence on the current tectonic units in the Tarim Basin, and affects the distribution of source rock in the Yuertus Formation and reservoir beds in the Xiaoerbulake Formation in Lower Cambrian, as well as the gypseous cap rock in Middle Cambrian. The distribution features of the rifts have important and realistic significance for determining the direction of oil and gas exploration in the deep strata of the Tarim Basin. Comprehensive analysis suggests that the Tazhong region is the most favorable zone, and the Kalpin-Bachu region is the optimal potential zone for exploring sub-salt oil and gas in deep Cambrian strata.  相似文献   

6.
The present study focuses on building a workflow for structural interpretation and velocity modeling and implementing to Jurassic-Cretaceous succession (Chiltan Limestone and Massive sand of the Lower Goru Formation). 2D-Migrated seismic sections of the area are used as data set and in order to confirm the presence of hydrocarbons in the study area, P and S-wave seismic velocities are estimated from single-component seismic data. Some specific issues in the use of seismic data for modeling and hydrocarbon evaluation need to deal with including distinguishing the reservoir and cap rocks, and the effects of faults, folds and presence of hydrocarbons on these rocks. This study has carried out the structural interpretation and modeling of the seismic data for the identification of traps. The results demonstrate existence of appropriate structural traps in the form of horst and grabens in the area. 2D and 3D velocity modeling of the horizons indicates the presence of high velocity zones in the eastern half of the study while relatively low velocity zones are encountered in the western half of the area. Two wells were drilled in the study area (i.e. Fateh-01 and Ichhri-01) and both are dry. Immature hydrocarbons migration is considered as a failure reason for Fateh-01 and Ichhri-01 well.  相似文献   

7.
Systematic geochemical studies of the Proterozoic Lengjiaxi Group in northeastern Hunan Province suggest that the Lengjiaxi Group is a Au-As-Sb-W association-type Au-bearing turbidite formation.The contents of Au,As,Sb,W,Cr,Mn,Pb and Zn in the turbidite formation are more than two times as high as the average contents of trace elements in the upper continental crust.The low abundance of Ag and the close correlation between Au and As are two important characteristic features.In the Au-bearing turbidite formation the enrichment of gold is due to the extensive occurrence of Au-bearing pyrites.Higher contents of Au,W,Sb and Ag in the greywacke indicate that they also exist in the form of heavy minerals.Au,Ag,As,Sb,W and REE in the Au-bearing turbidite formation have a close genetic relation with the chemistry of the gold deposits.  相似文献   

8.
The Songliao Basin is one of the most important petroliferous basins in northern China. With a recent gradual decline in conventional oil production in the basin, the exploration and development of unconventional resources are becoming increasingly urgent. The Qingshankou Formation consists of typical Upper Cretaceous continental strata, and represents a promising and practical replacement resource for shale oil in the Songliao Basin. Previous studies have shown that low-mature to mature Qingshankou shale mainly preserves type Ⅰ and type Ⅱ1 organic matter, with relatively high total organic carbon(TOC) content. It is estimated that there is a great potential to explore for shale oil resources in the Qingshankou Formation in this basin. However, not enough systematic research has been conducted on pore characteristics and their main controlling factors in this lacustrine shale reservoir. In this study, 19 Qingshankou shales from two wells drilled in the study area were tested and analyzed for mineral composition, pore distribution and feature evolution using Xray diffraction(XRD), scanning electron microscopy(SEM), low-pressure nitrogen gas adsorption(N2-GA), and thermal simulation experiments. The XRD results show that clay, quartz, and feldspar are the dominant mineral constituents of Qingshankou shale. The clay minerals are mostly illite/smectite mixed layers with a mean content of 83.5%, followed by illite, chlorite, and kaolinite. There are abundant deposits of clay-rich shale in the Qingshankou Formation in the study area, within which many mineral and organic matter pores were observed using SEM. Mineral pores contribute the most to shale porosity;specifically, clay mineral pores and carbonate pores comprise most of the mineral pores in the shale. Among the three types of organic matter pores, type B is more dominant the other two. Pores with diameters greater than 10 nm supply the main pore volume;most are half-open slits and wedge-shaped pores. The total pore volume had no obvious linear relationship with TOC content, but had some degree of positive correlation with the content of quartz + feldspar and clay minerals respectively. However, it was negatively correlated with carbonate mineral content. The specific surface area of the pores is negatively related to TOC content, average pore diameter, and carbonate mineral content. Moreover, it had a somewhat positive correlation with clay mineral content and no clear linear relationship with the content of quartz + feldspar. With increases in maturity, there was also an increase in the number of carbonate mineral dissolution pores and organic matter pores, average pore diameter, and pore volume, whereas there was a decrease in specific surface area of the pores. Generally, the Qingshankou shale is at a low-mature to mature stage with a TOC content of more than 1.0%, and could be as thick as 250 m in the study area. Pores with diameters of more than 10 nm are well-developed in the shale. This research illustrates that there are favorable conditions for shale oil occurrence and enrichment in the Qingshankou shale in the study area.  相似文献   

9.
The subduction of the Bangonghu-Nujiang Meso-Tethys and the collision between the Lhasa and Qiangtang blocks were important events in the growth of the Tibetan crust. However,the timing of collision initiation and closure timing,as well as nature and structure of the Bangonghu ocean basin,are still poorly constrained. The Lagkor Tso ophiolite,located in the south of Gerze County,Tibet,is one of the most completed ophiolites preserved in the southern side of the BangonghuNujiang suture zone. This study discussed the tectonic evolution of the Bangonghu-Nujiang suture zone as revealed by the Lagkor Tso ophiolite investigated by field investigations,petrology,geochemistry,geochronology and tectonic analysis methods. We present new LA-ICP-MS zircon U-Pb and 39Ar/40 Ar ages for the Lagkor Tso ophiolite,in addition to geochemical and platinum-group element(PGE) data presented for the Lagkor Tso ophiolite in Tibet. It is suggested that the ancient Lagkor Tso oceanic basin split in Middle Jurassic(161.2 ± 2.7 Ma – 165.4 ± 3.5 Ma),and experienced a second tectonic emplacement during the Early Cretaceous(137.90 ± 6.39 Ma). The Lagkor Tso ophiolite likely developed in an independent suture zone. The Bangonghu-Nujiang ocean subducted southwards,and the dehydration of the subducting oceanic crust materials caused partial melting of the continental mantle wedge,which formed the second-order expanding center of the obduction dish. This led to inter-arc expansion,followed by the formation of inter-arc and back-arc basins with island arc features,which are represented by ophiolites around the Shiquanhe-Lagkor Tso-Yongzhu region. The tectonic environment presently can be considered to be similar to that of the current Western Pacific,in which a large number of island arc-ocean basin systems are developed.  相似文献   

10.
This paper reviews the features of several tungsten ore deposits in southern China, including the Shezhuyuan, Yaogangxian, Xihuashan, Danping, Yiatang and Dajishan mines. The authors think that the formation depth of greisen-type deposits is intermediate between the depths of pegmatite- and porphyry- type deposits. Using phase diagrams of the model system K2O-AhO3-SiO2-H2O-HF, the formation mechanism of greisens has been argued. The variation of mineral assemblages from K-feldspar, muscovite to topaz reflects a gradual increase in acidity. This variation can be used as a criterion to appreciate the depth of mineralization. Equilibria of tungsten minerals in greisen and skarn deposits can be depicted on chemical potential diagrams of the model system CaO-FeO-WO3-CO2-F2O-1. The assemblage wolframite fluorite is shown to have been transformed to scheelite magnetite with decreasing μHP. Depending on CO2 activity in the fluids, there are two distinct phase diagrams.One shows that wolframite is incompatible with calcite, and the other demonstrates that scheelite is incompatible with rhodochrosite. On the phase diagrams of the model system FeO-MnO-WO3-F2S-1, huebnerite is transformed to ferberite with increasing μP1O-1orμF2S-1,During the replacement of wolframite by scheelite, the wolframite residue must have been enriched in Mn.  相似文献   

11.
塔东地区寒武—奥陶纪岩相古地理分析   总被引：1，自引：0，他引：1  
通过钻井资料以及露头资料的详细分析,在塔东地区寒武系—奥陶系识别出盆地相、斜坡相、台地相。根据盆地相沉积特征把塔东地区盆地相分为碳酸盐岩盆地、混积盆地、页岩-硅岩盆地三种类型。碳酸盐岩盆地相岩石类型为碳酸盐岩,混积盆地岩石类型为碳酸盐岩与页岩及硅岩互层,页岩-硅岩盆地岩石类型为泥页岩以及硅质岩。台地区发育台地边缘灰泥丘相、台缘滩相、开阔台地相等。灰泥丘主要为藻凝块岩,滩相主要为颗粒灰岩。综合塔里木盆地寒武纪—奥陶纪沉积特征提出了塔东地区碳酸盐岩沉积综合模式,并指出由台地至盆地方向,盆地由碳酸盐岩盆地向混积盆地及页岩-硅岩盆地过渡。在单井分析、露头资料分析、地震剖面分析的基础上,分析了塔东地区寒武纪—奥陶纪古地理展布。  相似文献   

12.
摘要：本文综述了同生断层控矿研究的进展,并结合在粤北地区的研究,论述了伸展及走滑盆地中同生断层的形成机制、特征和在盆地流体迁移和聚集中的作用以及与层控Ｐｂ－Ｚｎ（－Ｂａ－Ｃｕ－Ａｇ）等矿床的时空关系,认为沉积盆地中不同成因类型的层控矿床是盆地不同演化阶段的产物,成矿时空分异受同生断层和盆地流体系统的控制。  相似文献   

13.
华北地块南部晚古生代—三叠纪盆山耦合关系   总被引：9，自引：0，他引：9       下载免费PDF全文
华北地块南部的晚古生代至中生代初期发育有多种类型的沉积盆地,其形成演化直接受控于秦岭造山带的主造山作用过程,泥盆纪－石炭纪是岭与华北地块的点接触碰撞时期,古秦岭洋和二郎坪弧后盆地同期逐步消亡,深化为陆壳基础上的残余海盆地及残余弧后盆地,二叠为面接触碰撞阶段,豫西小秦岭岭段首先隆升,成为向北的物源区,在商丹－北淮阳主缝合带及其弧后残余盆地消亡的同时,华北地块南部形成盆地,并成为旱二叠世华北陆表海的沉积中心,秦岭与华北地块全面碰撞发生于三叠纪,在造山变质变形广泛活动的背景下,华北地块则形成了统一的大型坳陷型盆地。  相似文献   

14.
通化地区是松辽盆地东部外围的油气调查新区,油气勘探程度极低,关键问题是沉积地层展布形态、盆地深部结构等关键基础地质问题未知。笔者通过高精度重力、磁力和大地电磁等地球物理方法,获取了通化地区岩石地球物理和重磁异常变化特征,揭示了通化地区深部地球物理结构形态;认为通化地区存在4条Ⅰ级断裂和46条次级断裂,主要断裂控制着研究区的基本构造格架;首次圈定出红庙子、桓仁、沙尖子、拐磨子和木齐盆地5个断陷盆地,查明了盆地规模、中生界底面最大埋深和中侏罗统侯家屯组地层的展布形态等深部结构特征;并进一步对桓仁盆地和拐磨子盆地进行构造单元的划分。该研究成果为下一步油气勘探提供重要基础地质信息,亦对松辽盆地东部外围新区的油气勘探部署提供重要的指导意义。  相似文献   

15.
华南北部湾盆地的形成机制   总被引：1，自引：0，他引：1  
从北部湾盆地的区域地质构造背景、几何形态、边界断裂及内部断裂特征解析,综合沉积中心迁移规律及盆内构造研究,提出北部湾盆地为右行右阶走滑拉分成因。盆地的形成和发展受控于合浦-北流、信宜-廉江、吴川-四会和阳江-河源4条深大断裂带,这4条主干断裂带构成右阶断裂格架。古近系出现的花状构造等表现出典型的张扭特征,新近系受到压扭作用改造发生挤压反转,该盆地构造演化过程与华南大陆中、新生代拉分盆地具有同期性和相似性。中生代基底中先存的深大走滑断裂带是新生代北部湾盆地形成的先决地质条件。而印度-澳大利亚板块对欧亚板块碰撞挤压作用的逐渐增强和太平洋板块俯冲方向的改变及俯冲作用的衰减是控制北部湾盆地形成演化的区域大地构造因素。  相似文献   

16.
流体包裹体在沉积盆地分析中的应用   总被引：6，自引：0，他引：6  
系统介绍并探索流体包裹体在沉积盆地分析研究中下列７个方面的应用：即岩相和古地理分析；层地层学研究；阐明盆地热事件；再造盆地构造沉降史：探讨沉积有机演化史；恢复盆地埋藏史；盆地地下水动力状况模拟。  相似文献   

17.
西准噶尔吾尔喀什尔山与额敏盆地间的"盆"–"山"耦合关系清楚,盆地边界平行于造山带呈狭长带状展布。"山"区为志留系–石炭系海相陆源碎屑岩-火山岩沉积组合,"盆"区为二叠系陆相磨拉石与新近系红色砂砾岩及第四系河流阶地堆积,具有典型的海相-陆相双层结构。盆缘被巴尔雷克前陆冲断带围限,"山"区发育铲式逆冲断层与蛇头构造、叠瓦扇构造等逆冲推覆构造。表明该"盆"–"山"组合为一典型的前陆盆地系统。额敏前陆盆地形成于早二叠世,属后期冲断变形影响较弱、早期前陆盆地结构特征较明显的"早衰型"前陆盆地。这一成果为额敏盆地乃至西准噶尔盆地分析、构造演化、沉积作用、"盆"–"山"耦合等研究提供了重要信息。  相似文献   

18.
滇黔桂湘地区中生代复合大陆动力成矿系统特征   总被引：9，自引：0，他引：9  
通过大陆构造地质研究和分析认为在印支期SW→NE挤压构造应力场的驱动下,本区沉积盆地内可能形成自SW→NE向的盆地流体大规模流动(滇东南→桂西北)。在燕山早期,环太平洋板块自SE→NW挤压构造应力场驱动下,本区可能形成自SE→NW向的盆地流体大规模流动(桂东南→黔西北→滇东北),且可能被限定在康滇断块隆升区西边界的以东地区。在燕山晚期,伴随大陆构造进入伸展-走滑体制和山间断陷盆地的形成,幔源热物质侵位形成盆地流体的垂向热(流)应力驱动源,这种张剪性构造为流体成矿提供了良好的构造背景。古潜山、褶皱-断裂带、逆冲断裂-褶皱带和脆韧性剪切带可能是本区主要流体圈闭构造和矿床定位构造,成矿系列可划分为改造型拉分盆地中古潜山控制的F-Fe-S-Sb-Au成矿系列、褶皱-断裂带热水再造成因的Sb-As-Hg-Au成矿系列、改造型盆地边部逆冲断裂-褶皱带中热流体成因的Ge-Ag-Pb-Zn成矿系列和脆韧性剪切带中W-Sb-Au成矿系列。  相似文献   

19.
渤海湾地区X型正断层及油气意义   总被引：1，自引：0，他引：1  
本文主要利用地震资料解释成果,对渤海湾地区广泛发育的X型正断层的剖面变形特征、形成演化过程和机理及其油气意义进行分析。渤海湾地区X型正断层可分为新生型和继承型两类,在剖面上组合形成对称或非对称的X型形态。新生型和继承型X型正断层具有不同的形成演化过程与控制机理。新生型X型正断层与断裂带的右行走滑作用有关,是在断层的同步滑动过程中形成的。而继承型X型正断层的形成与基底先存断裂的继承性活动密切相关,是基底断裂优先活动的结果。渤海湾地区X型正断层对油气聚集成藏的有利作用主要表现在：有利于构造和地层圈闭的形成,有利于油气发生运移;有利于改善储层物性。与X型正断层相关的构造和地层圈闭是渤海湾地区值得关注的重要油气勘探领域。  相似文献   

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