瞬变电磁数据采集抗干扰措施评价方法

在煤田、矿区开展TEM勘查工作时,往往采取加大发射电流和发射面积、增加重复观测次数、迭加次数等抗干扰措施来获得符合要求的原始数据。为确定所采取抗干扰措施的有效性,建立相应的评价指标具有重要指导意义。为此,提出了TEM信噪比曲线的定义与统计方法,并提出用信噪比曲线评价抗干扰措施的有效性,认为信噪比大小变化能够真实反映原始数据的质量好坏及抗干扰措施是否有效。通过对矿区采取抗干扰措施后的实测数据进行统计分析,获得了不同措施下的信噪比资料。结果表明,本方法所得的信噪比参数易于统计,能够合理、有效地反应原始数据的质量以及抗干扰措施的应用效果。     

煤矿采区高密度三维地震采集参数讨论

随着煤矿采区高密度三维地震技术的不断推广,对其采集参数选择有了新的认识,特别是线束方向、线距大小、最大炮检距以及覆盖次数与CDP面元等关键采集参数的选择。从理论计算到工程实践角度,对煤矿采区高密度三维地震采集参数进行了分析与讨论,认为：道距、线距、炮点距、炮线距的大小与面元尺寸大小密切相关,能否实现无假频空间采样取决于面元大小,增大线距有利于提高性价比;以煤层构造勘探为目标的前提下,最大炮检距可以大于目的层埋深;在地震条件良好地区,高密度三维地震设计的覆盖次数不宜太高,以提高分辨率;高密度三维地震是面积采集、立体勘探,其线束方向设计不应受制于构造走向的约束。通过不同面元大小、不同覆盖次数以及大线距采集的典型工程实例,初步印证了上述结论的正确性。     

五维规则化技术在溱潼断阶带地震资料处理中的应用

溱潼断阶带地区为多期次三维地震采集的拼接区,不同期次的三维观测系统参数差异大,采集面元大小、覆盖次数、偏移距、方位角等属性不同,统一面元处理导致部分地区出现空面元;地表条件复杂,导致实际炮检点偏离设计点位,观测系统采样点不均匀,不能满足叠前偏移对地震采集信息规则分布的要求,造成地震数据偏移中出现假频、画弧等问题。从实际应用角度分析了基于匹配追踪傅里叶变换的叠前五维数据规则化技术在溱潼断阶带这一观测系统严重不规则区域的适用性,五维规则化技术较好地解决了区内因野外采集观测系统差异造成的地震属性不规则问题,提升了地震资料的信噪比及成像质量。     

煤田地震勘探中的可变线元采集技术及其应用

在复杂的地表地震地质条件及深部地震地质条件下,如何获得满足复杂地震勘探解释所需资料,有效地在资料采集费用和资料质量间作出优化选择显得尤为重要.为此,根据三维地震勘探面元叠加理论提出的可变线元采集技术,通过合理的布置激发点与接收点的位置,使得CMP点均匀分布在一个标准线元内.线元具有可分性,在不改变观测系统的前提下,可把标准线元调整到大小合适的尺寸,以便能够在增加覆盖次数和提高分辨率之间做出优化选择,为资料处理拓展空间,为资料解释提供多种不同覆盖次数的地震时间剖面.     

KLseis采集系统在复杂地表条件下资料采集中的应用

东滩矿一采区范围内村庄较多,施工的12束地震测线都经过大小不同的村庄,为保证村庄下叠加次数达到设计要求,利用KLseis采集系统进行特观设计,具体为:在大、小中疃,由于目的层埋深在660m左右,故采用村外加大炮检距放炮的方法,在后屯和东、西程家庄,由于目的层埋深浅,最大炮检距不宜超过550m,因此采用村内小药量(0.3～0.5kg)放炮的方法,确保障碍物下煤层反射波有足够的叠加次数。     

黄土塬区半规则束状观测系统的研究与应用

吕梁山脉中段西部黄土塬区,其浅表层地震地质条件极其复杂,常规规则束状观测系统难以取得有效波地震记录,考虑采集因素和施工特点,决定采用沟中激发、较少炮数、较多接收道数、较多排列线数、颇具灵活性的半规则束状观测系统。在实地踏勘和试验的基础上,利用采集软件对所获得的地震采集参数进行多次论证,以调整排列片的大小及炮点位置,合理编排放炮顺序,确保各目的层有效覆盖次数满足设计要求,同时兼顾资料处理和施工是否方便。实例表明：该区采用的半规则束状观测系统较好地解决了CDP分布以及资料完整性问题,处理后的剖面,其煤层反射波同相轴连续性较好,信噪比较高,主要目的层波组反射特征明显,可连续对比追踪,达到了采集目标的要求。     

高密度采集技术在西部煤炭资源勘探中的应用

结合中国煤炭地质总局承担的国家重大产业技术开发专项“西部煤炭资源高精度三维地震勘探技术”依托工程的研究成果,介绍了高密度三维地震勘探的概念、技术特点和优势。高密度三维地震采集技术与常规三维地震技术相比,具有高覆盖次数、小空间采样间隔、宽（全）方位角、均匀炮检距道集等特点,在资料采集和处理过程中容易接收并保护宽频数据,实现高信噪比、高分辨率、高保真度。实例说明小网格和高覆盖次数可有效提高地震资料信噪比和地震反射波的连续性,提高小构造的检测能力。根据多个依托工程的实施情况,提出了高密度三维地震采集技术对设备及野外采集的要求。     

设计实时控制高抗干扰软件的方法

本文分析了各种高抗干扰在实际环境下对软件运行的影响后果,探讨了防治软件抗干扰的问题,说明了实时控制高抗干扰软件的设计方法。     

被动源面波线形台阵在路基采空区勘查中的应用

被动源面波勘探又称作微动勘探,以其野外采集布设灵活、抗干扰、环境适应性强等优点,在城市工程勘察中的应用效果越发明显。文章以某地城市道路交通施工前期的采空区勘探工作为例,开展了被动源面波法线性台阵在探测路基下方采空区的应用效果研究,采用Atlas节点地震仪布置线形台阵采集微动数据,利用SWAINS面波处理软件提取微动数据的频散曲线,进而反演地下介质视横波速度剖面。试验结果表明,线形台阵被动源面波法适合于城市道路复杂场地环境下的采空区探测,钻探验证率高。     

基于UDEC颗粒模型的不确定性分析

颗粒模型的不确定性(颗粒形状、大小及空间分布等)严重影响岩石(体)数值模拟结果的可靠性与合理性。基于UDEC软件中的Voronoi颗粒模型,提出了两种Trigon颗粒模型的建立方法并通过软件自带的FISH语言实现。同时,深入分析了单轴压缩条件下颗粒形状、迭代次数(颗粒大小)和随机种子数(颗粒空间分布)对煤岩试样宏观力学行为及其破坏模式的影响。研究结果表明,迭代次数和随机种子数对煤岩单轴抗压强度及其变形特性的影响与颗粒形状相关:对于Trigon颗粒模型,两者影响程度相当;对于Voronoi颗粒模型,随机种子数的影响明显大于迭代次数。煤岩试样破坏过程中产生的微裂纹类型、数量及其发展规律主要受颗粒形状的影响,而受迭代次数和随机种子数的影响不大。岩石试样的破坏模式同时受颗粒形状、迭代次数和随机种子数的影响。因此,真实考虑岩石(体)组成物质的颗粒形状、大小及其空间分布,可有效提高颗粒模型数值模拟的真实性与可靠性。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861