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1.
大安寨段介壳灰岩作为四川盆地主要的非常规产油层,岩性及沉积特征较为特殊。通过野外露头观察及岩石薄片、铸体薄片、扫描电镜等分析手段,对重庆北碚地区下侏罗统自流井组大安寨段的沉积特征进行了系统分析。结果表明：重庆北碚地区侏罗系大安寨段岩性复杂,以亮晶介壳灰岩、粉晶白云岩、泥质介壳灰岩和泥页岩为主,次为生屑云岩和砂屑灰岩。大安寨段属受陆源碎屑影响明显的湖相碳酸盐岩沉积,可划分出滨浅湖亚相及高能介壳滩、高能砂屑介壳滩、滩间洼地、低能介壳滩等多个微相。其中,高能砂屑介壳滩水动力条件强、原生孔隙较发育。虽受埋藏成岩作用影响而使原生孔隙消耗殆尽,但后期溶蚀作用和构造作用改造仍可形成特低孔、低渗的非常规碳酸盐储层。 相似文献
2.
四川盆地侏罗纪大安寨段沉积时期水体富营养化,形成了介壳灰岩—泥页岩的湖相混积层系,为混积岩沉积机制研究提供了“天然实验室”。综合利用岩心、测井、录井等资料,以川北仪陇—营山地区为研究区,对大安寨段的岩性分类与沉积相展布特征进行研究,并讨论了该湖相混积层系的沉积过程与控制因素。结果表明: 大安寨段湖相混积层系以介壳组分与细粒硅质碎屑(包含黏土矿物)的混杂与交替为主,整体上可划分为一个完整的湖侵—湖退沉积旋回,大一亚段与大三亚段沉积时期介壳滩分布面积较大,大二亚段则广泛发育半深湖—深湖亚相,此外浅水介壳灰岩可在重力流驱动下于深水环境中发生搬运与再沉积作用; 混积过程主要为相混合与间断混合模式,混积作用受控于湖平面升降变化、物质来源、地质营力等因素,湖平面的升降变化控制着不同沉积微相的分布,地震、风暴浪等触发机制引起的重力流沉积促使不同微相与物质来源的沉积物(陆源碎屑搬运、生物—化学碳酸盐沉积、远源细粒物质悬浮等)相互混合,增加了混积岩内部的杂乱程度并扩大了混积岩的平面分布范围。本次研究建立了仪陇—营山地区大安寨段湖相混积层系沉积过程模式,可为陆相页岩油气勘探和相似地质背景下混积作用的成因研究提供借鉴和参考。 相似文献
3.
四川盆地中部侏罗系大安寨段含有机质泥质介壳灰岩储层的认识及其意义 总被引：1，自引：0，他引：1
四川盆地中部下侏罗统大安寨段可划分为三个亚段,主要由暗色泥页岩、结晶介壳灰岩、泥质介壳灰岩三种岩性构成。暗色泥页岩形成于深湖—半深湖相环境,是主要的烃源岩,滨浅湖高能滩相结晶介壳灰岩一向被认为是主要储层,其储集空间以裂缝为主。露头地质调查、岩心和薄片观察、物性资料及试油资料的分析表明,浅湖—半深湖较低能滩相含有机质泥质介壳灰岩是主要的储集层和产层,单层厚度薄,但累积厚度较大,分布面积广,常夹于暗色泥页岩中,源储一体,更有利于成藏。这类泥质介壳灰岩的壳间孔构成了主要的储集空间,壳间孔平行于壳体的长轴方向排列,并常见黑色有机质充填。认为四川盆地大安寨段的油气勘探方向可由结晶介壳灰岩向含有机质的泥质介壳灰岩拓展,浅湖—半深湖较低能滩沉积相带可成为新的勘探领域。初步预测大安寨段上部的一亚段新增有利勘探面积6 100 km2,中部的一三亚段新增有利勘探面积6 600 km2。 相似文献
4.
四川盆地下侏罗统自流井组大安寨段一亚段(大一亚段)灰岩是元坝地区主要产气层。岩心、薄片、物性资料、试油、录井、测井、地震资料综合研究表明,大一亚段灰岩主要为介壳灰岩和含泥介壳灰岩,介壳灰岩平均孔隙度236%,平均渗透率为002×10-3 μm2,含泥介壳灰岩平均孔隙度为459%,平均渗透率为021×10-3 μm2。介壳灰岩为浅湖亚相高能滩微相沉积,含泥介壳灰岩为浅湖亚相次高能滩微相沉积。地震波形分类上,以介壳灰岩为主的高能滩微相为高连续低频中强波谷反射,以含泥介壳灰岩为主的次高能滩微相为高连续低频中弱振幅波谷反射。高连续低频中强振幅波谷反射和高连续低频中弱振幅波谷反射以SW-NE向分布于研究区中央地带。以伽马值大于46 API为门槛值剔除泥岩、泥质粉砂岩等,得到介壳灰岩和含泥介壳灰岩的伽马数据体。精细刻画了高能滩微相介壳灰岩和次高能滩微相含泥介壳灰岩的分布范围,新增天然气有利区面积518 km2,为元坝地区大安寨段天然气储量和产量的增加奠定了坚实的基础。 相似文献
5.
四川盆地回龙地区下侏罗统自流井组大安寨段混积岩特征及模式 总被引：1，自引：0，他引：1
川西回龙地区自流井组大安寨段发育湖相碳酸盐岩和碎屑岩的混合沉积,结合野外露头、钻井岩芯、测井和显微组构等资料的综合分析,对该研究区混积岩沉积微相特征进行了精细刻画。研究认为,回龙地区大安寨段属湖泊混合沉积相,分为滨浅湖混合沉积和半深湖混合沉积两个亚相,并划分了五个沉积微相,分别为高能介壳滩混合沉积微相,低能介壳滩混合沉积微相,砂质浅滩混合沉积微相,浅湖混合沉积微相以及半深湖混合沉积微相。基于所划分的混合沉积相的特征和四川盆地以及研究区回龙大安寨段在侏罗纪的沉积相演变过程,分析了该区混积岩的成因及混合沉积演化模式。得出结论:研究区湖相混合沉积主要受物源供给和水动力条件的控制,在五种不同混合沉积微相控制作用下形成了不同类型的混积岩。 相似文献
6.
四川盆地下侏罗统自流井组大安寨段一直是四川盆地致密油勘探的重要层位之一。针对该层位的研究已逾半个世纪,但岩石类型分类粗略、沉积环境及储集岩类型认识不清等问题是导致该层段致密油勘探未获重大突破的重要原因。鉴于此,笔者等开展了对四川盆地东部重庆北碚和平水库剖面下侏罗统自流井组大安寨段湖相碳酸盐岩岩石类型及沉积环境的研究。研究发现,该剖面大安寨段为湖相碎屑岩与碳酸盐岩的混合沉积,由5大类岩石组成,可细分为14种岩石类型。碳酸盐岩厚度占剖面总厚度的60％以上,以泥晶灰岩为主,介壳灰岩和介屑灰岩次之;在纵向上形成了4个较为典型的向上变浅沉积序列。根据各岩石类型宏观、微观沉积特征及岩石纵向组合形式,进一步分析了各岩石类型的沉积环境,结果表明,北碚地区下侏罗统大安寨段沉积时期为滨、浅湖环境,以低能碳酸盐沉积为主;高能与较低能环境成因的介壳滩并非碳酸盐沉积的主体。湖泊进入碳酸盐沉积阶段和钙质骨壳生物的大量繁育是大安寨期湖相碳酸盐岩形成的主要原因。结晶介屑灰岩和泥晶白云岩可能是川东地区致密油的储集岩类,在今后的勘探中,应提高对滨浅湖环境、易受大气淡水改造的岩石类型的重视程度。 相似文献
7.
下侏罗统自流井组大安寨段作为四川盆地致密油主产层,蕴含着丰富的油气资源,在川中地区已稳产数十年。川东地区大安寨段一直未取得突破,相应的研究程度较低。本文选取重庆万州地区大垭口剖面下侏罗统自流井组大安寨段作为研究对象,针对其发育稳定保存良好的湖相碳酸盐岩开展研究,通过研究发现:万州地区大安寨段以湖相碳酸盐岩和碎屑岩混合沉积为特征,其主要由5大类岩石组成,共细分为12种岩石类型。结合岩性、沉积特征及区域上的资料,可将大垭口剖面大安寨段划分出半深湖—深湖、湖坡、浅湖、滨湖4个亚相及多个微相。大安寨段由下往上可分为大三、大二以及大一共三个亚段,发育了一个完整的湖侵—湖退沉积旋回。其中,大三亚段和大一亚段岩性以介壳或介屑灰岩和结晶介壳灰岩为主,夹薄层黑色泥页岩及砂岩;大二亚段岩性以黑色页岩为主,夹薄层介壳灰岩。根据各岩石类型宏观、微观特征及岩石纵向组合特征,分析各亚相的沉积环境。结果表明:万州地区下侏罗统大安寨段沉积环境整体属于较低能沉积环境,碳酸盐岩中多为泥晶方解石胶结,含泥质。根据实测剖面及区域上的资料,建立了川东北地区大安寨段湖泊相沉积模式,该模式总结了该区域大安寨段各亚相的发育特征及演化规律。 相似文献
8.
川中地区下侏罗统自流井组大安寨段湖相页岩非均质性强,有利岩性组合的研究对目标层段的选取较为关键.通过对21口井的岩心观察与描述、有机质含量与主微量元素测定等,划分了岩性段及组合类型,并探讨了各组合类型特征.结果表明:大二亚段页岩层系主要发育泥质介壳灰岩、灰黑色页岩、含介壳页岩3类岩性,针对其生物介壳发育的特征,识别出特殊的介壳层岩性段;进一步总结出4类岩性段类型,A块状介壳灰岩段、B页岩与介壳层互层段、C页岩夹介壳层段、D纯页岩段.4类岩性段的古环境特征差异反映了不同的页岩油潜力,半潮湿-潮湿的古气候、较高的古生产力、合适的沉积速率,以及缺氧还原、半咸水-淡水环境有利于有机质的富集与保存,由此综合优选出有利岩性段类型为C页岩夹介壳层段,D纯页岩段次之. 相似文献
9.
文井—明月地区大安寨段是川中地区的主要产油层,储层具有明显的特殊性。其储集岩类主要为介壳灰岩和含泥介壳灰岩,原生孔隙在强烈的压实和胶结作用影响下消耗殆尽,但喜山期的构造作用在其灰岩段中产生了一定数量的构造缝,这些构造缝在后期溶蚀过程中可形成少量溶蚀孔、洞,与层理缝和方解石解理缝构成了大安寨油藏的主要储集空间和渗流通道,属于典型的特低孔-裂缝型储层。储层的分布主要受到滨浅湖高能介壳滩和裂缝发育程度的影响。 相似文献
10.
为查明川北地区大安寨段页岩油气烃源、储集特征及富集有利层段,以岩芯观察描述为基础,以岩石学与矿物学、有机地球化学及页岩储层表征等理论方法与技术为指导,开展了大安寨段二亚段纵向上4个小层岩相、烃源、储集特征的精细表征与差异性对比研究,优选出了页岩油气富集有利层段,并提出勘探研究建议。研究结果表明：大安寨段二亚段富含（泥质）介壳灰岩、（泥质纹层状）粉细砂岩2种夹层,低—中碳黏土质页岩、中碳纹层—薄层状介壳页岩、低碳（纹层状）粉砂质页岩、低碳粉砂质介壳灰质页岩4种页岩岩相;②小层以中碳黏土质页岩、中碳纹层状介壳页岩为主,夹层相对少,页岩连续性较好;而④小层以中碳纹层状介壳页岩夹介壳灰岩为主,不同尺度介壳灰岩夹层多。页岩有机显微组分整体以镜质组为主,②、④小层固体沥青较发育,自下而上有机质类型发生6次变化,依次为Ⅲ—Ⅱ2—Ⅲ—Ⅱ2—Ⅱ1—Ⅱ2;②小层与④小层生油气能力相对较好,④小层略好于②小层。页岩储集物性明显好于夹层,②小层和④小层页岩生烃能力相对好,有机质孔较发育,含气量相对高,页岩烃源—储集—含（油）气性匹配关系相对好,评价认为大安寨段二亚段上部④小层纹层状介壳页岩段为最佳页岩油气富集层段,其次为下部②小层黏土质页岩层段。基于研究区大安寨段二亚段沉积非均质性强、含油气性好的层段时空分布不稳定的特点,建议重视砂、泥、灰混积差异,加强以小层为单元的岩相（组合）时空分布规律研究;重视保存条件与含气性差异,加强常规—非常规一体油气勘探选区、选层研究。 相似文献
11.
奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提 相似文献
12.
A catastrophic rockslide-debris flow in Wulong, Chongqing, China in 2009: background, characterization, and causes 总被引：7，自引：3，他引：4
Qiang Xu Xuanmei Fan Runqiu Huang Yueping Yin Shengshan Hou Xiujun Dong Minggao Tang 《Landslides》2010,7(1):75-87
On June 5, 2009, a catastrophic rockslide-debris flow occurred at the crest of the Jiweishan Mountain in Wulong, Chongqing,
China. Approximately five million cubic meters of limestone blocks slid along a weak interlayer of bituminous and carbonaceous
shale. The source mass descended from the upper part of the slope rapidly, crossing a 200-m wide and 50-m deep creek in front
of it. Blocked by the opposite steep creek wall, the sliding mass changed its direction and traveled a further 2.2 km along
the creek in debris-flow mode, finally forming a large accumulation zone with an average depth of 30 m. This is one of the
most catastrophic rockslide events in recent years in China. It buried 12 houses and the entrance of an iron mining tunnel
where some 27 miners were working inside. Ten people died, 64 missing, and eight wounded. Immediately after this disaster
happened, the government organized an expert team to assist the rescue work. As one of the geological experts, the author
did a lot of field investigations and collected first-hand information. Multi-methods including the remote sensing, 3D laser
scanning, geophysical exploration, and numerical modeling were used for analyzing the characteristics and the triggering mechanism
of the Wulong rockslide. The preliminary investigation results reveal that this rockslide with poor geological conditions
was mainly induced by the gravitation and the karst effect and also affected by the previous mining activities. The research
in this paper is meaningful and useful for further research on such kind of rockslides that are geologically similar to the
Wulong rockslide. 相似文献
13.
Joseph Clancy White 《Contributions to Mineralogy and Petrology》1993,113(4):524-532
The textural relationships and structural states of optically isotropic labradorite from the Manicouagan, Quebec, impact structure have been examined by light (optical) and transmission electron (TEM) microscopy. Two distinct diaplectic glasses have been recognized based on their contrasting morphology, timing and the inferred modes of formation. The earliest isotropic bands and grain-scale isotropism (maskelynite) optically exhibit a gradational,in situ transformation from crystalline plagioclase with preservation of relict textures (twins, grain boundaries). The same transformation from crystalline to amorphous structure is observed in TEM to occur heterogeneously at scales on the order of the unit cell. The progressive transformation of optical properties reflects an increase in the volume fraction and eventual coalescence of these amorphous units. This maskelynite-type diaplectic glass is interpreted to form in the solid-state directly from crystalline material during the compressional phase of the shock wave. The other isotropic material occurs in spatially discrete tensiongashes and planar deformation features (PDFs) that overprint the maskelynite-type glass. This second type of diaplectic glass (PDF-type) is developed homogeneously within a given glass band and exhibits sharp crystal-glass boundaries, in contrast to the gradational boundaries of the maskelynite-type glass. PDF-type glass is interpreted to form by melting in tensional release zones during passage of the rarefaction wave. These observations emphasize the ability of naturally shocked rocks to preserve subtle evidence of variations in the shock process from highly transient events. 相似文献
14.
S. Viswanathan K. Surya Prakash Rao B. Mahabaleswar 《Journal of the Geological Society of India》2013,82(6):621-627
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours. 相似文献
15.
Xiaoyu ZHAO Wuyi WANG Hairong LI Fujian FENG Lizhen WANG 《中国地球化学学报》2006,25(B08):80-81
Brick-tea-type fluorosis is a peculiar endemic disease in China, which had been discovered in minority areas of western China since 1980, and distributed mainly in Tibet, Inner Mongolia, Gansu, Xinjiang, Qinghai and parts of Sichuan Province. The prevalence rate of fluorosis in Tibetan and Mongolian nationality people was higher. Epidemiological investigation showed that fluorosis morbidity and degrees were different in different brick-tea drinking areas, and it was probably caused by drinking various kinds of brick tea from different regions. Therefore, we collected 33 samples of brick tea from six provinces where minority nationalities were accustomed to drinking a large quantity of brick tea. F concentrations were determined by the combustion hydrolysis-ion selective electrode method. The results showed that among the brick teas, the F concentrations ranged from the minimum 74.1 mg/kg in Yunnan Province to the maximum 991.2 mg/kg in Sichuan Province. Besides, there was a great difference among the various kinds of brick tea, and F concentrations decreased in the order of Kang brick tea, Green brick tea, Black brick tea, Mi brick tea, Fu brick tea, Chitsu ping tea, Puerh tea, and Tuo tea. The average F concentration in brick teas was 431.92 mg/kg. 相似文献
16.
Natural Hazards - Despite the application of various methods to calculate uncertainty in flood vulnerability assessments, the challenge of uncertainty remains. The main purpose of this study was to... 相似文献
17.
L. I. Mashonkina A. B. Vinogradova D. A. Ptitsyn V. S. Khokhlova T. A. Chernetsova 《Astronomy Reports》2007,51(11):903-919
We derived Sr, Y, Zr, and Ce abundances for a sample of 74 cool dwarfs and subgiants with iron abundances, [Fe/H], between 0.25 and ?2.43. These estimates were obtained using synthetic spectra, assuming local thermodynamic equilibrium (LTE) for Y, Zr, and Ce, allowing for non-LTE conditions for Sr. We used high-resolution (λ/Δλ?40 000 and 60 000) spectra with signal-to-noise ratios between 50 and 200. We find that the Zr/Y, Sr/Y, and Sr/Zr ratios for the halo stars are the same in a wide metallicity range (?2.43 ≤ [Fe/H] ≤ ?0.90), within the errors, indicating a common origin for these elements at the epoch of halo formation. The Zr/Y ratios for thick-disk stars quickly decrease with increasing Ba abundance, indicating a lower rate of production of Zr compared to Y during active thick-disk formation. The thick-disk and halo stars display an increase in the [Zr/Ba] ratio with decreasing Ba abundance and a correlation of the Zr and Eu overabundances relative to Ba. The evolutionary behavior of the abundance ratios found for the thick-disk and halo stars does not agree with current models for the Galaxy’s chemical evolution. The abundance ratios of Y and Zr to Fe and Ba for thin-disk stars, as well as the abundance ratios within each group, are, on average, solar, though we note a slight decrease of Zr/Ba and Zr/Y with increasing Ba abundance. These results provide evidence for a dominance of asymptotic-giant-branch stars in the enrichment of the interstellar medium in heavy elements during the thin-disk epoch, in agreement with the predictions of the nucleosynthesis theory for the main s-process component. 相似文献
18.
Arsenic concentrations of less than 5 ppb to as large as 1,260 ppb in stream waters and from 5 ppm to 4,000 ppm in stream
sediments were found in the Pedro Dome-Cleary Summit area, Alaska. Waters from three of 20 wells sampled had arsenic concentrations
exceeding the U.S. Public Health Service recommended limit of 50 ppb. The high arsenic levels are a consequence of arsenic
enrichment in the rocks of the area. Placer and lode-gold mining may increase the arsenic content of the waters by exposing
arsenic-containing rocks to surface waters and by increasing the load of arsenic-rich sediments in the streams. Finding these
disturbingly large concentrations of arsenic in the waters of the Fairbanks area was the major result of this work, inasmuch
as a subsequent study (to be published) revealed arsenic concentrations as large as 10 ppm in domestic wells and prompted
an extensive study by Federal and State agencies of the health hazard posed by these arsenic-rich waters. 相似文献
19.