纵横波弹性阻抗联立反演在GD地区的应用   总被引：2，自引：0，他引：2  

戴晓峰  甘利灯  杜文辉 《应用地球物理》2006,3(1):37-41

在GD油田复杂油藏描述中应用叠前纵横波弹性阻抗反演,精确地进行了油藏岩性的划分。利用三个或三个以上部分叠加数据,进行纵横波弹性阻抗联立反演,既克服了因叠后地震反演结果单一而不能满足复杂储层描述的需求,又避免了由于叠前道集信噪比低造成反演结果不稳定的缺陷。本文论述了叠前弹性波阻抗反演的基本原理,结合GD地区实际资料,对反演过程中涉及的角道集子波提取、层位标定、横波速度预测、弹性参数提取与解释等关键步骤进行了详细研究,指出基于测井资料分析的多种弹性参数综合解释是提高叠前地震反演应用效果的关键。  相似文献   

基于共炮偏移的AVO反演   总被引：8，自引：0，他引：8  

首皓  刘洪  高建虎 《应用地球物理》2006,3(2):98-104

常规AVO多是利用CMP道集的振幅进行反演。主要有三个方面影响其精度:首先,CMP道集假设地下为水平层状介质,但是实际地下介质多为倾斜地层,地层倾角越大CMP道集的振幅所反映地下介质的位置与实际位置差距就越大。其次,NMO、DMO和反褶积等常规处理流程,都会造成振幅值失真。第三,反演所用的反射系数公式是与入射角有关的量,而欲从CMP道集得到准确的入射角与振幅之间的对应关系,则十分困难。波动方程叠前深度偏移除对复杂介质和陡倾角地层具有较强的成像能力,还可以最大限度的减少常规处理所带来的误差并使振幅归位。本文综合了保幅偏移、角度道集提取以及AVO反演等前人的工作,提出直接从炮集数据反演AVO属性的方法,以期显著减少上述三个因素对AVO反演精度的影响。  相似文献   

利用天顶对流层延迟数据直接推算水汽含量的研究   总被引：4，自引：0，他引：4  

曲建光  刘基余  韩中元 《武汉大学学报(信息科学版)》2005,30(7):625-628

比较和分析了北京、拉萨和武汉等跟踪站2002年7月的天顶对流层延迟和大气综合水汽的变化趋势,提出了无需进行其他转换利用天顶对流层延迟直接推算水汽含量的新方法,并对实测数据的计算结果进行了验证,证明了该方法的可行性。  相似文献   

天文测量中减弱大气折射影响的方法   总被引：1，自引：0，他引：1  

张超郑勇  夏治国 《测绘学院学报》2005,22(2):85-87

大气折射是对天文测量精度影响较大的因素之一，至今无法将其完全消除，只能尽量减弱。因此，处理好大气折射改正，是提高天文测量精度的一项重要任务。文中分析了大气折射的特点．介绍了传统天文测量对大气折射的处理方法；研究并实现了新的处理大气折射的方法，给出了具体解算公式。新方法的应用，使天文测量的效率、精度都得以大大提高。  相似文献   

Magion-4 High-Altitude Cusp Study     

J. Merka  J. Šafránková  Z. Němeček  J. Šimůnek 《Surveys in Geophysics》2005,26(1-3):57-69

The polar cusps have traditionally been described as narrow funnel-shaped regions of magnetospheric magnetic field lines directly connected to magnetosheath ones, allowing the magnetosheath plasma to precipitate into the ionosphere. However, recent middle- to high-altitude observations (i.e., the Interball, Hawkeye, Polar, Image, and Cluster spacecraft) reported the cusps to encompass a broad area near local noon. The present paper focuses on a statistical study of the high-altitude cusp and surrounding magnetosheath regions as well as on some peculiarities of the cusp-magnetosheath transition. For a comparison of high- and low-altitude cusp determination, we present a mapping of two-year Magion-4 (a part of the Interball project) observations of cusp-like plasma along model magnetic field lines (according to the Tsyganenko 96 model) down to the Earth’s surface. The footprint positions show a substantial latitudinal dependence on the dipole tilt angle. The dependence can be fitted by a line with a slope of 0.14° MLAT per 1° of tilt. In contrary to previously reported IMF or solar wind influences on the cusp shape or location, some differences exist: (1) a possible IMF B_X dependence of the cusp location, (2) a split cusp for B_Y≠ 0, and (3) a smaller cusp during periods of higher solar wind dynamic pressure. The conclusions following from the statistical analysis are confirmed by case studies which reveal the physical mechanisms leading to the observed phenomena. Results have shown that (1) reconnection near the cusp does not necessarily lead to observable precipitation, (2) the cusp precipitation in one hemisphere can be supplied from the conjugate hemisphere, and (3) the cusp geometry at a certain time depends on the IMF history.  相似文献   

山地大倾角地层三维地震资料处理研究   总被引：2，自引：1，他引：2  

马社坤 夏青徐爽  张安徽 《中国煤田地质》2005,17(4):41-44

山地大倾角地层的三维地震资料处理的核心问题是如何解决3D反射面元发散，增加反射面元内道集同相叠加，而静校正技术和偏移成像技术正是解决这一问题的关键技术。以XJ区的三维地震勘探为例，对其资料进行综合静校正及叠前偏移成像技术处理，较好地解决了该区的地层构造成像和分辨率问题，保证了勘探精度。  相似文献   

The misorientation index: Development of a new method for calculating the strength of lattice-preferred orientation   总被引：5，自引：4，他引：5  

Philip Skemer  Ikuo Katayama  Zhenting Jiang  Shun-ichiro Karato 《Tectonophysics》2005,411(1-4):157-167

Using orientation data from experimentally deformed olivine, we explore some practical problems with the J-index, a commonly applied measure of fabric strength. We show that the J-index is highly dependent on several factors, including the number of discrete data in the orientation distribution function (ODF), and arbitrary numerical parameters specified for its calculation. Because of this non-uniqueness, we conclude that the J-index is difficult to interpret and should only be applied with caution. As an alternative to the J-index, we propose a new measure of fabric strength that is based on the distribution of uncorrelated misorientation angles. This “M-index” is shown to be insensitive to the parameters specified for its calculation. For typical deformed olivine samples, we show that 150 discrete data are adequate to quantify fabric strength using the M-index technique. The M-index correlates well with seismic anisotropy, particularly for materials of the same fabric type. Therefore, we conclude that the M-index technique is well-suited for the quantification of fabric strength and the comparison of like materials.  相似文献   

Absolute S-velocity estimation from receiver functions   总被引：2，自引：0，他引：2  

L. Svenningsen  B. H. Jacobsen 《Geophysical Journal International》2007,170(3):1089-1094

We present a novel method to recover absolute S velocities from receiver functions.
For a homogeneous half-space the S velocity can be calculated from the horizontal slowness and the angle of surface particle motion for an incident P wave. Generally, the calculated S velocity is an apparent half-space value which depends on model inhomogeneity and P -waveform. We therefore, suggest to calculate such apparent half-space S velocities from low-pass filtered (smoothed) receiver functions using a suite of filter-parameters, T . The use of receiver functions neutralize the influence of the P -waveform, and the successive low-pass filterings emphasize the variation of S velocity with depth.
We apply this   V _{S ,app.}( T )  technique to teleseismic data from three stations: FUR, BFO and SUM, situated on thick sediments, bedrock and the Greenland ice cap, respectively. The observed   V _{S ,app.}( T )  curves indicate the absolute S velocities from the near surface to the uppermost mantle beneath each station, clearly revealing the different geological environments. Application of linearized, iterative inversion quantify these observations into   V _S ( z )  models, practically independent of the S -velocity starting model. The obtained models show high consistency with independent geoscientific results. These cases provide also a general validation of the   V _{S ,app.}( T )  method.
We propose the computation of   V _{S ,app.}( T )  curves for individual three-component broad-band stations, both for direct indication of the S velocities and for inverse modelling.  相似文献   

粒状碎屑溜砂坡的形成和基本特征研究（溜砂坡系列研究之一）     

王成华  张小刚  阙云  何思明 《岩土力学》2007,28(1):29-35

通过现场考察和室内模型试验，研究了粒状碎屑溜砂坡形成的“三大要素”——砂源区、溜动区和形成区、粒状碎屑溜砂坡形成条件和演化规律、研究了粒状碎屑溜砂坡的散体结构特征和天然休止角。通过影响天然休止角的主要因素和显著性分析，研究了天然休止角的线性回归方程以及粒状碎屑溜砂坡的稳定性和判别标志。  相似文献   

Reply to Comment on “The Misorientation index: Development of a new method for calculating the strength of lattice-preferred orientation”     

Philip Skemer  Shun-ichiro Karato 《Tectonophysics》2007,441(1-4):119-120

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