开江—梁平台内海槽东段长兴组白云岩储层沉积-成岩系统研究     

张兵  杨凯  贾雪丽  郑荣才  郭强  文华国 《吉林大学学报(地球科学版)》2017,(6):1631-1641

为了指导部署四川盆地白云岩储层中钻井,在油气钻井岩心观察与描述、野外剖面实测和样品采集的基础上,结合镜下薄片鉴定、X衍射、物性和地球化学特征分析,对开江—梁平台内海槽东段长兴组白云岩储层的沉积-成岩系统进行了深入研究。认为台地边缘生物礁和台地边缘浅滩为最重要的储集相带,颗粒白云岩、生物礁白云岩和晶粒白云岩为最主要的储集层岩性,晶间孔、晶间溶孔和超大溶孔为目的层最有效的储集空间,孔洞缝复合型储层为目的层最优质的储集类型。综合分析认为,长兴组沉积-成岩系统与白云岩储层在时空上具有良好的耦合关系,台地边缘生物礁和台地边缘浅滩相控制了白云岩储层的区域分布范围,而不同成岩系统对储层的贡献程度不同。其中:地层封存卤水与混合热卤水成岩系统是储层形成的基础与关键,地层封存卤水形成低孔低渗的孔隙型Ⅲ类储层,混合热卤水形成中孔中渗的孔洞型Ⅱ类储层;构造热液成岩系统对储层贡献最大,并形成高孔高渗的孔洞缝复合型Ⅰ类优质储层。  相似文献   

Hydrothermal dolomite reservoir in the Precambrian Dengying Formation of central Sichuan Basin,Southwestern China     

《Marine and Petroleum Geology》2017

The Precambrian Dengying Formation is maximum buried carbonate reservoir in the Sichuan Basin. Reservoir types are thought to be dominated by sedimentary facies or karst controlled. Precursory sedimentary fabrics have been intensively superimposed by medium-to coarse-grained dolomite in most areas. Dolomitized intervals contain planar and saddle dolomite, quartz, and few hydrothermal replacive minerals. Fluid inclusion analyses of dolomite suggests that rocks are formed at temperatures ranging from 132.6°C to 218.7°C in the presence of dense brines, while the dolomite phases are demonstrated by negative δ¹⁸O and δ¹³C VPDB values. Strontium isotopes enriched in ⁸⁷Sr, and the fluid source could support the conclusion. The dolomites of the Dengying Formation in central Sichuan Basin that formed around basement-rooted wrench faults, in turn mainly oriented towards the North-South and East-West strike-slip faults, are detectable. Lastly, the grabens take the form of negative flower structures-the result of an intra-cratonic rift that took place during the Sinian and early Cambrian period through tensional faulting.Our primary contention is that basement fault, which resulted in the magmatic or deep clastic fluids migration, was key for the formation of the obvious high-temperature coarse dolomite and saddle dolomite replacement. Subsequently, hot fluids that circulated within the matrix dolomite were aided by fractures or vugs and (1) leached into the dolomite, producing vugs and pores; (2) precipitated saddle dolomite, and (3) led to hydrofracturing, fractures enlargement, and further brecciation. The dolomite eventually formed porous hydrocarbon reservoirs through diagenesis. This model better illustrates how fluids that originated from deep basin migration along strike-slip transfer faults and fractures flowed out to structures in Precambrian basement-rooted faults, inheriting the rift in the Cambrian. The data involved offers a fresh perspective pertinent to deep hydrocarbon exploration of dolomite reservoirs in Southwestern China.  相似文献   

Characterization of the Microbial Dolomite of the Upper Sinian Dengying Formation in the Hanyuan Area of Sichuan Province, China   总被引：1，自引：1，他引：0  

LIN Xiaoxian  PENG Jun  DU Lingchun  YAN Jianping  HOU Zhongjian 《《地质学报》英文版》2017,91(3):806-821

The algal dolostone of the Upper Sinian Dengying Formation (corresponding to the Ediacaran system) in the Upper Yangtze Platform of China possesses a rich diversity of microorganisms and is an ideal site for the study of ancient microbial dolomite. We focused on algal dolostone and its microbial dolomite in the Hanyuan area of Sichuan Province, China. The macroscopic petrological features, microscopic morphology, texture characteristics of the fossil microorganisms and microbial dolomite, and geochemical characteristics were investigated. We found rich fossil microorganisms and microbial dolomites in the laminated, stromatolithic, uniform and clotted (algal) dolostones. The microorganisms present were mainly body fossils of cyanobacteria (including Renalcis, Girvanella, Nanococcus, and Epiphyton) and their trace fossils (including microbial mats (biofilms), algal traces, and spots). In addition, there was evidence of sulfate-reducing bacteria (SRB), moderately halophilic aerobic bacteria, and red algae. The microbial dolomites presented cryptocrystalline textures under polarizing microscope and nanometer-sized granular (including spherulitic and pene-cubical granular) and (sub) micron-sized sheet-like, irregular, spherical and ovoidal morphologies under scanning electron microscope (SEM). The microbial dolomites were formed by microbially induced mineralization in the intertidal zone and lagoon environments during the depositional and syngenetic stages and microbially influenced mineralization in the supratidal zone environment during the penecontemporaneous stage. The microbial metabolic activities and extracellular polymeric substances (EPS) determined the morphology and element composition of microbial dolomite. During the depositional and syngenetic stages, the metabolic activities of cyanobacteria and SRB were active and EPS, biofilms and microbial mats were well-developed. EPS provided a large number of nucleation sites. Accordingly, many nanometer-sized pene-cubical granular and (sub) micron-sized sheet-like microbial dolomites were formed. During the penecontemporaneous stage, SBR, cyanobacteria, and moderately halophilic aerobic bacteria were inactive. Furthermore, nucleation sites reduced significantly and were derived from both the EPS of surviving microorganisms and un-hydrolyzed EPS from dead microorganisms. Consequently the microbial dolomites present nanometer-sized spherulitic and micron-sized irregular, spherical, and ovoidal morphologies. Overall, the microbial dolomites evolved from nanometer-sized granular (including spherulitic and pene-cubical granular) dolomites to (sub) micron-sized sheet-like, irregular, spherical and ovoidal dolomites, and then to macroscopic laminated, stromatolithic, uniform, and clotted dolostones. These findings reveal the correlation between morphological evolution of microbial dolomite and microbial activities showing the complexity and diversity of mineral (dolomite)-microbe interactions, and providing new insight into microbial biomineralization and microbial dolomite in the Precambrian era.  相似文献   

Activity of Silica-Rich Hydrothermal Fluid and Its Impact on Deep Dolomite Reservoirs in the Sichuan Basin, Southern China     

ZHU Dongy  ZHANG Dianwei  LIU Quanyou  JIN Zhijun  HE Zhiliang 《《地质学报》英文版》2017,91(6):2214-2229

Well-developed dissolution pores occur in the dolomites of the Sinian Dengying Formation, which is an important oil and gas reservoir layer in the Sichuan Basin and adjacent areas in southern China. The pores are often filled with quartz, and some dolomites have been metasomatically altered to siliceous chert. Few studies have documented the characteristics, source or origin of silica-rich fluids and their effects on the dolomite reservoir. The peak homogenisation temperatures(T_h) of fluid inclusions in pore-filling quartz are between 150℃ and 190℃, with an average of 173.7℃. Gases in the inclusions are mainly composed of CO_2, CH_4 and N_2. Compared with host dolomite, pore-filling quartz and metasomatic chert contain higher amounts of Cr, Co, Mo, W and Fe, with average concentrations of 461.58, 3.99, 5.05, 31.43 and 6666.83 ppm in quartz and 308.98, 0.99, 1.04, 13.81 and 4703.50 ppm in chert, respectively. Strontium levels are lower than that in the host dolomite, with average concentrations in quartz and chert of 4.81 and 11.06 ppm, respectively. Rare earth element compositions in quartz and chert display positive Eu anomalies with a maximum δEu of 5.72. The δD_(SMOW) values of hydrogen isotopes in water from quartz inclusions vary from-85.1‰ to-53.1‰ with an average of-64.3‰, whereas the δ~(18)O_(SMOW) values range from 7.2‰ to 8.5‰ with an average of 8.2‰. The average ~(87)Sr/~(86)Sr ratios in quartz and chert are 0.711586 and 0.709917, respectively, which are higher than that in the host dolomite. The fluid inclusions, elemental and isotopic compositions demonstrate that the formation of quartz and chert was related to silica-rich hydrothermal fluid and that the fluid was the deep circulation of meteoric water along basement faults. Interactions with silica-rich hydrothermal fluids resulted in densification of dolomite reservoirs in the Dengying Formation through quartz precipitation and siliceous metasomatism. However, it increased the resistance of the host dolomite to compaction, improving the ability to maintain reservoir spaces during deep burial. Evidence for silica-rich hydrothermal activity is common in the Yangtze Platform and Tarim Basin and its influence on deep dolomite reservoirs should be thoroughly considered.  相似文献   

川东北飞仙关组白云岩岩石结构演化   总被引：1，自引：1，他引：0  

杨博  蔡忠贤  赵文光 《现代地质》2010,24(5):945-950

根据矿物结晶学理论,白云石可按照晶体大小和晶边形貌划分为不同的结构,其结构的演化主要受原岩化学组成、岩石结构和白云岩化流体的影响。白云岩原岩可分为不同化学组分的泥灰岩和含颗粒泥灰岩,泥灰岩可细分为成分均匀的和含溶孔、胶结物的泥灰岩;含颗粒泥灰岩可细分为未接受任何改造的、发生溶蚀胶结作用的和发生泥晶化等作用的含颗粒泥灰岩。以川东北飞仙关组白云岩为例,在不同浓度的白云岩化流体条件中,讨论不同结构白云岩岩石的演化。结果表明：泥晶化及溶蚀作用是白云石岩石结构演化和形成的基础;大多数鲕粒白云岩在低浓度白云岩化溶液中形成;糖粒状白云岩为外来高浓度的白云岩化流体改造形成。  相似文献   

Using in situ REE analysis to study the origin and diagenesis of dolomite of Lower Paleozoic,Tarim Basin     

WANG XiaoLin  JIN ZhiJun  HU WenXuan  ZHANG JunTao  QIAN YiXiong  ZHU JingQuan & LI Qing State Key Laboratory for Mineral Deposits Research  School of Earth Sciences  Engineering  Nanjing University  Nanjing  China  Petroleum Exploration  Development Institute of SINOPEC  Beijing  SINOPEC Northwest Oil Field Branch  Urumqi 《中国科学D辑(英文版)》2009,(5)

In situ REE concentrations of various dolomites from Tarim Basin were obtained by LA-ICP-MS analysis,and the data were normalized to standard seawater(Seawater Normalized=SWN).Most of the samples have a ΣREE range of less than 20 ppm.All samples show similar REESWN distributions with heavy REE depletion,and positive Ce anomaly,which indicates that they have the same dolomitization fluids(seawater).According to the origin and diagenetic process of dolomite,two types of dolomite are determined and described a...  相似文献   

施秉喀斯特地貌世界遗产价值研究   总被引：2，自引：0，他引：2  

李高聪  熊康宁  肖时珍  周明忠 《热带地理》2013,33(5):562-569

对施秉喀斯特演化环境、地貌类型及分布、地貌演化史、石灰岩与白云岩地貌差异等特征进行研究,试图提炼施秉喀斯特的世界遗产地貌价值。研究表明：施秉喀斯特具有热带―亚热带地区独特的喀斯特地貌演化环境;展示了热带―亚热带地区独特而典型的白云岩峰丛峡谷喀斯特地貌景观,从分水岭至峡谷区呈现了峰林洼地―峰林谷地―峰丛谷地―峰丛峡谷喀斯特地貌逆向回春演替规律,是白云岩峡谷喀斯特地貌形态及地貌演化的模式地;记录了古生代以来3次较大的碰撞运动,即早古生代的加里东运动,晚古生代的海西造山运动,及中、新生代以来的印支运动、燕山运动和喜马拉雅山运动。燕山运动是本区最强烈的造山运动,产生了区内众多褶皱和断裂构造,奠定了施秉地区的地貌构造轮廓。喜马拉雅山运动,尤其是第二、三幕运动,全面塑造了施秉喀斯特峡谷地貌;施秉白云岩喀斯特地貌展现出与石灰岩封闭型地貌不同的以开放型地貌为主的特征,在中国南方喀斯特系列自然遗产中有重要地位,具备地貌世界遗产价值。  相似文献   

新疆三塘湖盆地中二叠统芦草沟组湖相白云岩成因^*   总被引：3，自引：3，他引：0       下载免费PDF全文

李红  柳益群  梁浩  周小虎  焦鑫  刘洪福  杨锐  雷川 《古地理学报》2012,14(1):45-58

新疆三塘湖盆地中二叠统芦草沟组发育湖泊背景下的白云岩、灰岩、黑色泥岩、页岩及碎屑岩的互层沉积。白云岩主要有两类：一类为粉—泥晶白云岩,主要由含量约70％的泥晶白云石和含量约30％的粉晶白云石构成,白云石有序度为0.48,扫描电镜下主要有菱形、他形、球状和管状4种微形态,自形程度较好的菱形晶体多为含铁白云石;另一类为方沸钾长白云岩,主要由晶粒为0.08～0.35mm的细粒方沸石、泥晶钾长石（透长石）、泥晶白云石和铁白云石构成,个别为粗晶白云石,白云石有序度0.58。与粉—泥晶白云岩中的白云石相比,方沸钾长白云岩中的白云石以高的铁、锰含量为特征,扫描电镜下多为半自形的菱形晶体。两类白云岩中白云石的有序度均较低,且均为富Sr白云石,内部均缺乏次生交代证据。通过对两类白云岩成分、微量元素及稳定同位素的差异性分析,认为尽管两类白云岩都形成于浅—半深湖相强还原沉积环境,但是它们的形成机制有所不同,粉—泥晶白云岩具有原生沉淀白云石的特征,其中球状及管状的白云石可能与微生物吸附作用有关,而他形及菱形的白云石为直接沉淀的原生白云石;另一类方沸钾长白云岩中的白云石及铁白云石可能与湖底热泉的喷流沉积作用有关。  相似文献   

350ka以来北冰洋波弗特环流演变及其沉积响应          下载免费PDF全文

叶黎明  葛倩  杨克红  许冬 《海洋学研究》2012,30(4):20-28

波弗特环流(Beaufort Gyre)是 决定北冰洋海冰运移方向和滞留时间的主要因素。依据沉积物的颜色旋回、Mn元素含量和有孔虫丰度,本文建立了阿尔法洋脊(Alpha Ridge)B85-D孔轨道尺度上的年龄框架,并深入分析了该孔晚第四纪以来冰筏碎屑(IRD>154 μm)含量、组分及其源区的变化特点。结果表明,350ka以来最显著的变化发生在末次冰期(MIS2~4期),期间沉积物中Ca元素和白云石含量都接近于零,大部分来自班克斯岛、维多利亚岛和麦肯齐地区的碳酸盐岩碎屑没有在阿尔法洋脊沉积;随着波弗特环流的消亡,搬运陆源碎屑的海冰很可能沿着北美海岸线直接进入了欧亚海盆。而在末次间冰期(MIS5期),波弗特环流却十分流畅,并将大量碳酸盐岩碎屑限制在美亚海盆内,导致阿尔法洋脊沉积物中Ca元素含量急剧升高,与之对应的白云石含量高达16.4%。通过类比可知,在MIS6期波弗特环流的状态可能与MIS2~4期相似,而在MIS8和MIS10这两大冰期,波弗特环流却类似于MIS5期。显然,波弗特环流的存在与否并不严格遵循“冰期-间冰期”旋回,这种变化很可能是风场强度和海冰浓度双重作用的结果。  相似文献   

巴楚地区上寒武-下奥陶统丘里塔格群碳酸盐岩储层特征   总被引：5，自引：0，他引：5  

张新海  王晓东  阳国进  周新桂  毛晓长 《地质力学学报》2002,8(3):257-264

巴楚地区上寒武-下奥陶统丘里塔格群碳酸盐岩储层是区内主要储层段,为一套局限台地沉积,其中"云岩、灰岩互层段"、"白云岩段"为有利储层层位。受沉积相、成岩作用和构造作用影响,储集空间类型主要是次生孔隙、溶洞和裂缝,尤其是溶蚀作用与断裂改造作用,使丘里塔格群碳酸盐岩形成优质储层。分布在南部康塔库木-玛扎塔格构造带已获得高产工业气流。   相似文献