VSP 高斯射线束法叠加成像

叠加是地震数据处理的核心环节,可以有效地压制噪声提高信噪比。在 VSP 地震勘探中,常规的叠加方法在复杂构造中成像精度受到极大的限制。文中采用高斯射线束方法对复杂构造进行正演模拟,将得到的波场特征与实际资料波场特征进行对比,调整参数获得合适的速度场;在叠加过程中采用逆高斯的思想,对实际地震资料共炮集数据进行反射波场归位,得到共反射点道集数据,选择合适的面元尺寸进行叠加获得复杂构造的叠加波场特征。通过大量模型测试,VSP 高斯束叠加方法可以有效地反演地下结构特征。应用该方法对 M 地区进行成像研究,结果表明该方法能够准确反演地下结构特征,为数据处理与解释提供依据。     

3万年以来日本海西部海冰活动变化

海冰是现代气候系统的一个基本组成要素,对气候变化有着重要的调控作用。现今日本海西部仍发育有限的季节性海冰,也是深层水形成的关键区域。由于缺乏沉积岩芯,长期以来对日本海西部海冰范围变化的历史还缺乏深入的认识。本文对日本海西部LV53-18-2岩芯中长393 cm的沉积物进行了粒度分析,采用粒径端元分析方法,重建了过去30.0~5.0 ka海冰和底流活动历史。粒径端元(EM)分析显示,端元3(40~160 μm)是指示海冰活动的有效指标;EM1(2~20 μm)与可分选粉砂平均粒径呈现一致的变化趋势,是指示底流活动的有效指标,但在15.0~7.8 ka受到冰筏碎屑影响。日本海西部海冰活动由冬季海冰形成和春/夏季海冰融化条件的共同制约。末次冰期-冰盛期(30.0~18.0 ka),在强盛东亚冬季风(EAWM)和低太阳辐射量控制下,日本海西部季节性海冰活动保持微弱;在末次冰消期晚期-中全新世早期(15.0~7.8 ka),EAWM仍然强盛,同时北半球高纬日射量和海平面升高,导致海冰活动十分活跃;7.8~5.0 ka以来,随着EAWM减弱和对马暖流入侵,日本海西部季节性海冰活动显著减弱。在海因里希冰阶(HS)1时段(17.5~15.0 ka),大西洋经向翻转流减弱诱发EAWM增强,同时北半球夏季太阳辐射量和海平面都相对较低,可能导致日本海西部海冰持续覆盖。在季节性海冰形成时期,盐析过程增强了水体垂向对流和底流活动,但是在HS1,深层水体形成源区被常年海冰覆盖,抑制了深层水形成,减弱了研究区底流活动。

     

Origins of heavy oils in the Erlian Basin, ne China

The Erlian Basin is located in the Central Asia-Mongolian fold belt between the Siberian and Sino-Korean Cratons. It is a Mesozoic continental rift basin composed of 52 individual fault-depressions. The main phase of rifting took place during the Early Cretaceous when a series of fluvial-lacustrine sediments were deposited. Each depression forms an independent sedimentary system and behaves as an independent petroleum system. Hydrocarbon source rocks are found in the upper Arshan and lower Tengger Formations. These are mainly type II source rocks and are mainly located in oil generation window at the present day. A series of oilfields and commercial oil flows have been found in the basin, highlighting its good petroleum potential. Many of these oils are heavy.Six oil samples from the Anan and ten from the Jirgalangtu Depressions have been subjected to routine geochemical analytical techniques in order to evaluate the origins. The methods used include gas chromatography of the saturated and aromatic hydrocarbon fractions, gas-chromatography-mass-spectrometry of the saturated hydrocarbon fraction and stable carbon isotope analyses. The trace metal elements of the biodegraded oils from the Jirgalangtu Depression were also analysed by atomic absorption spectroscopy.Two types of heavy oils : primary and biodegraded were identified on the basis of these data. The former includes both immature and mature heavy oils. A filtering-and-spill process was proposed to explain the origin of primary mature heavy oils (or tar-mat) in the Anan Depression. The biodegraded oils from the Jirgalangtu Depression were ranked and classified in terms of the degree of biodegradation, using a series of geochemical parameters based on the gas chromatographic concentrations and biomarker fingerprints of gas-chromatography-mass-spectrometry of the saturated hydrocarbon fraction. The relationship between oil saturation and porosity indicates that the heavy oils in the Jirgalangtu Depression were biodegraded after they accumulated.     

日较差分级的北京地面逐时气温预报

统计了不同日较差等级与其相应等级内的逐时气温的气候平均值及逐时气温变量气候平均值,在此基础上客观自动地计算出北京区域的分片逐时气温预报值,由此次生出与气温变化有关的专业气象预报产品,应用于专业气象业务。     

郁江南宁段致洪气象特征分析

郁江南宁段致洪气象特征的分析表明,热带气旋影响左、右江流域是致洪的主要原因;洪峰出现前的第9到第5天的流域降雨量对洪水的形成具有最重要的作用.     

龙感湖水生植被

于１９９３年９月对龙感湖水生植被及环境进行了调查研究。龙感湖有水生植物２６科３８属５０种,依据优势种群划分９个群丛,其分布面积２８３．５ｋｍ＾２,占全湖总面积的８９．７％,植被现有年生产力达２１４７７３０ｔ,对渔业生产和生态环境具有十分重要的意义。建议对该湖植被应合理开发利用,如果围网养鱼得到广泛地发展,渔业生产潜力每年可达４１８１．８ｔ。     

重排藿烷:示踪油藏充注途径的分子标志物

基于C30重排藿烷(C30DH)和C30藿烷(C30H)热稳定性差异,研究了C30DH/C30H作为油气运移方向和充注途径的可行性.结果发现:C30DH结构稳定性高于C30H,C30DH/C30H参数具有成熟度属性;同时对比分析C30DH/C30H参数与咔唑类参数的相关性,认为两者之间正相关性明显,表明C30DH/C3...     

Urbanization of Jilin Province and Its Spatial Pattern

1 Introduction It is indisputable that the urbanization has been consid- ered as an important indicator for evaluating a nation’s or a region’s modernization and industrialization. Therefore, the issue of urbanization will arouse wide and remarkable concern in both domestic and international geography in the 21st century. From a comprehensive survey of the development of urbanization all over the world, some successful modes of urbanization, such as the American mode and the Japanese mode, …     

Evolution and effect of the stress concentration and rock failure in the deep multi-seam coal mining

Supports crushing accident occasionally occurs in the protected seam exploitation of deep multi-seam coal mining structure and results in adverse effect to the production. To prevent its recurrence in a newly developed working field, a 3D numerical extraction model was built based on the geologic and mining conditions of Jining coal mine to evolve the changes, state and characteristics of the reconstructed vertical and lateral stress in rock interlayer after protective seam exploitation. Stress release and increase zones of this mining structure were separated. Mining-induced localized stress concentration and the interlayer rock failure behavior were explored. The action of concentrated stress on the hydraulic supports in protected seam was discussed upon the major stress redistribution. Using the infinitesimal strain method, a mechanical model was created to further explore, from the vertical and lateral directions, the cause and mechanism of localized stress concentration and rock failure behavior in rock interlayer. The field investigation was finally performed to verify the numerical and mechanical results, and the essential control measures were proposed to prevent this accident. Key findings of this study bring some new insights into the deep multi-seam coal extraction and help to promote a more reliable underground mining.     

Strontium isotopic geochemistry of Tianqiao Pb-Zn deposit,Southwest China

Tianqiao carbonate-hosted Pb-Zn deposit, controlled by NW-trending F37 thrust fault and NW-trending Tianqiao anticline, is located in the eastern part of Sichuan-Yunnan-Guizhou （SYG） Pb-Zn metallogenic province, southwestern Yangtze Block, southwest China. Ore bodies in this deposit are hosted in the Devonian-Carboniferous carbonate rocks, and ore minerals include sphalerite, galena and pyrite, while the gangue minerals are dominated by calcite and dolomite. Using high-precision solid thermal ionization mass spectrometry （TIMS）, this paper reports the strontium isotopic compositions （0.7119 to 0.7167） of sulfide samples from the Tianqiao deposit in order to trace the origin of hydrothermal fluids. Compared with the country rocks, the calculated 87Sr/86Sr200 Ma values of sulfide range from 0.7118 to 0.7130, higher than those of the age-corrected Devonian to Permian sedimentary rocks （0.7073 to 0.7101） and the Middle Permian Emeishan flood basalts （0.7078 to 0.7039）, but lower than those of the age-corrected Proterozoic basement rocks （such as the Kunyang and Huili Groups, 87Sr/86Sr200 Ma=0.7243 to 0.7288）. This implies a mixed strontium source between the older basement rocks and the younger cover sequences. Together with geologic and previous isotopic evidences, we considered that the fluids＇ mixing is a possible mechanism for sulfide precipitation in the Tianqiao deposit.