等时叠加波动方程叠前正演

非零炮检距地震正演模拟在复杂区叠前地震资料处理和解释中有着重要意义。通常使用射线追踪法和全程波动方程法来实现这一模拟。通过提出等时叠加原理和数学检波器表达式，形成了非零炮检距地震正演的新一类方法——单程波动方程法。该方法与射线追踪法相比能保持波的动力学特征，正演结果与实际地震记录相似性好。并且在计算过程中，人工干预的程度低，操作简便。与全程波动方程法相比，该方法计算效率高，且不产生直达波、多次波等干扰，信噪比高，与目的层相对应的一次波突出，波型识别难度不大。因此，单程波动方程法特别适合于复杂油气藏反射地震资料的正、反演研究。     

近断层地震动模拟现状

地震动是由3个物理过程（震源破裂过程、波传播过程、场地反应）组成的一种复杂系统的产物,地震动模拟均是围绕这3个物理过程的建模开展的。地震动模拟目前仍然是一门相对较新的科学,强震观测中不断发现的新情况、新问题及其深入研究进一步推动近断层地震学理论和实践的发展。减少建模中的不确定性,用基于观测物理学的统计特征逐渐取代基于现象的假设描述,以改善地震动模拟的精度。基于大量地震动模拟的研究文献和资料,归纳、评述了近断层地震动模拟方法的现状、3个物理过程的建模方法及其发展趋势。     

Standard cumulative semivariograms of stationary stochastic processes and regional correlation

The standard cumulative semivariograms (SCS), obtained analytically from the currently employed stationary stochastic processes, provide a basis for the model identification and its parameter as well as regional correlation estimations. The analytical solutions for different stationary stochastic processes such as independent (IP), moving average (MA), autoregressive (AR), and autoregressive integrated moving average ARIMA (1,0,1) processes give rise to different types of SCSs which can be expressed in terms of the autocorrelation structure parameters only. The SCSs of independent and MA processes appear as linear trends whereas other type of processes have SCSs which are nonlinear for short distances but become linear at large distances. Irrespective of the stationary stochastic process type the linear portions of SCSs have unit slopes. The vertical distance between these linear portions and that of the IP cumulative semivariogram (CS), provide an indicator for measuring the regional correlation. In the case of stationary processes, the straight line portions of any CS are parallel to each other. Hence, it is possible to identify the model from the sample CS. Finally, necessary procedures are provided for the model parameters estimation. The methodology developed, herein, is applied to some hydrochemical ions in the groundwater of the Wasia aquifer in central part of Kingdom of Saudi Arabia.     

不排水抗剪强度非平稳随机场模拟及边坡可靠度分析

边坡可靠度分析中通常假定采用平稳或准平稳随机场表征土体参数的空间变异性,然而大量现场试验数据表明,土体参数如不排水抗剪强度沿土体埋深常呈现明显的非平稳分布特征,即其均值和标准差均随埋深发生变化,因此亟需发展土体参数非平稳随机场模型及其模拟方法。针对目前不能有效单独模拟土体参数趋势分量和随机波动分量的不确定性,提出了一种有效的不排水抗剪强度参数非平稳随机场模型,并给出了土体参数二维非平稳随机场模拟方法计算流程,同时将新提出的模型与现有非平稳随机场模型及平稳随机场模型进行了系统比较。最后通过不排水饱和黏土边坡算例验证了提出模型的有效性,并揭示了不排水抗剪强度非平稳分布特征对边坡可靠度的影响规律。结果表明：提出模型能够有效地单独模拟土体参数趋势分量和随机波动分量的不确定性,考虑土体参数均值和标准差随埋深增加而增大的特性,可为表征土体参数非平稳分布特征提供了一条有效的途径。此外,与采用非平稳随机场模拟土体参数空间变异性相比,采用常用的平稳随机场模型会低估边坡失效概率,从而造成偏危险的边坡工程设计方案。     

基于VMD和SVM的煤厚预测方法研究

煤厚变化对煤炭安全高效开采具有重要的影响。针对三维地震数据中含有噪声时,易导致煤厚预测结果具有较大误差的问题,提出一种利用变模态分解(VMD)和支持向量机(SVM)方法结合进行煤厚预测的方法。首先,构建煤厚楔形模型并对其进行地震正演模拟,当煤层厚度较薄时,振幅属性和频带宽度属性与煤厚之间具有较好的正相关性,而瞬时频率属性与煤厚具有较好的负相关性;对正演地震记录增加噪声,结果表明噪声对利用地震属性进行煤厚预测具有较大影响。利用VMD进行去噪之后,基于SVM进行煤厚预测,实际地震资料的煤厚预测结果与已有钻孔揭露的煤层信息较为吻合,预测煤厚最小绝对误差仅为0.02 m,最大绝对误差0.52 m,验证了方法的可行性和有效性。研究成果可为低信噪比区的煤厚反演提供参考。      

Use of tsunami waveforms for earthquake source study

Tsunami waveforms recorded on tide gauges, like seismic waves recorded on seismograms, can be used to study earthquake source processes. The tsunami propagation can be accurately evaluated, since bathymetry is much better known than seismic velocity structure in the Earth. Using waveform inversion techniques, we can estimate the spatial distribution of coseismic slip on the fault plane from tsunami waveforms. This method has been applied to several earthquakes around Japan. Two recent earthquakes, the 1968 Tokachi-oki and 1983 Japan Sea earthquakes, are examined for calibration purposes. Both events show nonuniform slip distributions very similar to those obtained from seismic wave analyses. The use of tsunami waveforms is more useful for the study of unusual or old earthquakes. The 1984 Torishima earthquake caused unusually large tsunamis for its earthquake size. Waveform modeling of this event shows that part of the abnormal size of this tsunami is due to the propagation effect along the shallow ridge system. For old earthquakes, many tide gauge records exist with quality comparable to modern records, while there are only a few good quality seismic records. The 1944 Tonankai and 1946 Nankaido earthquakes are examined as examples of old events, and slip distributions are obtained. Such estimates are possible only using tsunami records. Since tide-gauge records are available as far back as the 1850s, use of them will provide unique and important information on long-term global seismicity.     

Pressure-related feedback processes in the generation of pseudotachylytes

Pseudotachylyte formation is typically viewed as a self-limiting process. Quantitative models have demonstrated that frictional melting is possible at seismic slip rates, but once a thin film of melt forms on a seismic fault plane, the dramatic decrease in fault friction is thought to suppress further melting. Volumes of melt-generated pseudotachylyte observed in field studies, however, are in many cases substantially larger than the amounts of frictional melt predicted by theoretical models. This suggests that previously unrecognized physical processes may enhance melting during seismic slip. Localized decompression at dilational jogs may be one such phenomenon. Transient unloading could play two important roles in the dynamics of pseudotachylyte generation. First, by setting up significant fluid pressure gradients, it would lead to rapid migration of the melt to sites of low pressure, thereby reestablishing frictional contact across the fault surface and favoring further melt generation. Second, at significant depths, sudden depressurization might lead to in situ decompression melting.     

Direct Pattern-Based Simulation of Non-stationary Geostatistical Models

Non-stationary models often capture better spatial variation of real world spatial phenomena than stationary ones. However, the construction of such models can be tedious as it requires modeling both statistical trend and stationary stochastic component. Non-stationary models are an important issue in the recent development of multiple-point geostatistical models. This new modeling paradigm, with its reliance on the training image as the source for spatial statistics or patterns, has had considerable practical appeal. However, the role and construction of the training image in the non-stationary case remains a problematic issue from both a modeling and practical point of view. In this paper, we provide an easy to use, computationally efficient methodology for creating non-stationary multiple-point geostatistical models, for both discrete and continuous variables, based on a distance-based modeling and simulation of patterns. In that regard, the paper builds on pattern-based modeling previously published by the authors, whereby a geostatistical realization is created by laying down patterns as puzzle pieces on the simulation grid, such that the simulated patterns are consistent (in terms of a similarity definition) with any previously simulated ones. In this paper we add the spatial coordinate to the pattern similarity calculation, thereby only borrowing patterns locally from the training image instead of globally. The latter would entail a stationary assumption. Two ways of adding the geographical coordinate are presented, (1) based on a functional that decreases gradually away from the location where the pattern is simulated and (2) based on an automatic segmentation of the training image into stationary regions. Using ample two-dimensional and three-dimensional case studies we study the behavior in terms of spatial and ensemble uncertainty of the generated realizations.     

地震储层表征:在模拟储层的三维地震响应时考虑盖层、地震勘探布局和储层物性的敏感度(英文)

根据三维地震地质模型对地震数据进行模拟是从勘探到生产的周期内决策过程中的一个不可或缺的组成部分。虽然对于在储层内的动力过程和地震地质的模型表述已经取得很大进展,但如何从这些模型得到地震数据的精确模拟仍面临很多挑战。通常是在地球模型范围内根据物性用一维褶积方法来模拟地震数据。然而这个过程一般不考虑地震勘探布局和盖层对地震信号的影响。我们审视了为什么这些因素会制约三维地球模型的有效性,并考虑了为什么需要把盖层和地震勘探布局对三维覆盖和分辨率的影响加进模拟过程之中。我们提出了一种新方法,把建立物性模型和一种新的地震模拟技术结合起来,给出一个工作流程;利用这个流程,勘探工作者可以很快模拟出三维的PSDM数据,这些数据加进了盖层和地震勘探布局对覆盖及分辨率的影响。我们利用从远离挪威海岸的一个油田得到的数据,在考虑覆盖和分辨率效应的地震数据模拟之前,对岩石物性做了一些扰动,然后进行地震数据模拟,以此来说明如何可以用这种方法提高三维地球模型的精确性和增进我们对储层的了解。     

干旱区内陆河流域生态水文综合集成研究

针对干旱区内陆河流域生态环境问题,面对国家重大需求及地球系统科学发展方向,指出内陆河流域生态水文综合集成研究的必要性,旨在为精细管理水资源,提高单方水产出效益（经济效益和生态效益）提供思路。以黑河流域为例,追踪流域研究历程,目前从野外调查试验观测,模型模拟到研究平台建设,黑河流域的数据知识的积累已基本具备开展流域生态水文综合集成的条件,但仍然存在着巨大的挑战。根据存在的问题,提出未来进行集成研究应加强的3个方面：①加强综合观测;②强调人文因素的定量研究和人文过程的研究;③重视模型、模拟方法在描述和反演地理真实中的应用。     

Multiple-Point Simulation with an Existing Reservoir Model as Training Image

The multiple-point simulation (MPS) method has been increasingly used to describe the complex geologic features of petroleum reservoirs. The MPS method is based on multiple-point statistics from training images that represent geologic patterns of the reservoir heterogeneity. The traditional MPS algorithm, however, requires the training images to be stationary in space, although the spatial distribution of geologic patterns/features is usually nonstationary. Building geologically realistic but statistically stationary training images is somehow contradictory for reservoir modelers. In recent research on MPS, the concept of a training image has been widely extended. The MPS approach is no longer restricted by the size or the stationarity of training images; a training image can be a small geometrical element or a full-field reservoir model. In this paper, the different types of training images and their corresponding MPS algorithms are first reviewed. Then focus is placed on a case where a reservoir model exists, but needs to be conditioned to well data. The existing model can be built by process-based, object-based, or any other type of reservoir modeling approach. In general, the geologic patterns in a reservoir model are constrained by depositional environment, seismic data, or other trend maps. Thus, they are nonstationary, in the sense that they are location dependent. A new MPS algorithm is proposed that can use any existing model as training image and condition it to well data. In particular, this algorithm is a practical solution for conditioning geologic-process-based reservoir models to well data.     

频率域单程方程三维叠前正演中的波场替换

利用定位原理进行三维叠前正演,仅靠单程声波方程的延拓即可形成复杂地质条件下的正演记录,运算效率高无多次反射出现。但速度模型中对于过大或过小的速度常使波场在延拓时有频率和波数成分的损失,这种损失引起波场畸变并严重影响正演记录的质量。本文采用波场替换技术,在每次延拓时用零相位子波形成一个同时保留了原波场的动力学特征与空间位置信息的新波场,然后用新波场取代原畸变波场并参与正演记录合成。在频率域单程方程三维叠前正演中特别适合做波场替换,因为震源脉冲与接收响应(均可视为点脉冲)的延拓波场在形态上相似,而且在延拓波场中每道记录之振幅包络只有一个极值点。理论试算结果表明,采用波场替换技术后最终正演记录质量比替换前有了很大改善。      

地震波场正演模拟中的有限单元方法

本文介绍了地震波场正演模拟中的有限单元方法。首先从粘弹性波动理论出发,推导了满足粘弹性介质的有限元方程,其次用不含阻尼矩阵的有限元方程模拟了地震记录。地表实例是自由界面的瑞雷面波。VSP记录有水平层、倾斜层;有零井源距和非零井源距;有线状和对称震源。 在程序中采用了超压缩存贮和分块计算措施,对降低有限元法要求计算机内存和运算速度的苛刻条件上做了有益的尝试。     

现有液化识别方法对比分析

场地液化实时监测和报警是减轻液化灾害的新途径,其核心技术是建立依据强震记录对液化场地进行反演识别的方法。采用统一样本,其中尽可能多地包含软土场地地震动记录,按场地类别对目前国内外现有的Suzuki法、Miyajima法、KY法和SY法等4种主要液化识别方法的可靠性进行了对比分析,提出评价结果及改进建议。分析表明：对全部样本,SY法、Suzuki法、KY法和Miyajima法识别成功率依次为98%、85%、77%和52%;Suzuki法、KY法和Miyajima法的成功率受场地类别影响显著,随场地变软而明显降低,对D类场地识别成功率均在55%以下;Suzuki法、Miyajima法和KY法均采用与绝对周期相关的参数作为判别指标,而软土与液化场地上存在明显交叉,极易导致误判;SY法选取地震动参数的相对变化作为识别指标,即使对D类场地成功率也达到92%,但其方法中仍有若干细节需要进一步探讨和改进     

论糜棱岩研究

糜棱岩是一种具有丰富地质信息的载体，在理论和实践上都有重要的研究意义。从显微超微构造，岩石固态流变，动力变质成矿，成岩模拟实验，构造地球化学，造山带运行学和同位素年代学等七个方面，较全面的阐述了近20年来糜棱岩岩石学的研究进展情况。并简单列举了一些新成果，诸如浅层次糜棱岩的发现，人工糜棱岩的成岩实验和同位素测年新数据等。同时还指出糜棱岩的微观研究可进一步拓展到壳幔流变学，构造年代学和造成带比较学等这些新的学科研讨上。     

90°相位转换技术在预测砂体展布中的应用

以黄河口凹陷西洼沙河街二段为例,对研究区地震剖面进行90°相位转换,根据转换后的剖面岩性特征及地质背景概况建立地质模型,进行正演模拟分析;然后对比零相位与90°相位的正演合成记录,校准地质模型,并依据地震剖面振幅属性特征,对相位转换后的地震剖面进行属性提取,预测砂体的展布.研究发现,基于90°相位转换地震剖面建立的地质模型更具直观性,正演合成记录验证砂岩恰好对应于波谷,波形能清晰地展示出砂岩层的纵向轮廓,并且90°相位转换的地震波谷振幅值属性平面图能清晰显示出砂体的平面展布及分布范围.     

陆相层序地层学理论体系及其发展趋势

笔者在综合了国内外大量学者研究成果的基础之上，以全新的角度，从陆相层序几何学和陆相层序充填动力学两个方面，初步总结了陆相层序地层的特征，研究难点，层序的内部构成和外部构成。地层的控制因素。并且简略地归纳了陆相层序地层学的模式。展望了未来陆相层序地层学的发展趋势及其前景。     

Generalized cross-covariances and their estimation

Generalized cross-covariances describe the linear relationships between spatial variables observed at different locations. They are invariant under translation of the locations for any intrinsic processes, they determine the cokriging predictors without additional assumptions and they are unique up to linear functions. If the model is stationary, that is if the variograms are bounded, they correspond to the stationary cross-covariances. Under some symmetry condition they are equal to minus the usual cross-variogram. We present a method to estimate these generalized cross-covariances from data observed at arbitrary sampling locations. In particular we do not require that all variables are observed at the same points. For fitting a linear coregionalization model we combine this new method with a standard algorithm which ensures positive definite coregionalization matrices. We study the behavior of the method both by computing variances exactly and by simulating from various models.     

Paleoseismicity and geodynamics in Sweden

Paleoseismicity denotes past (pre-instrumental) earthquakes as recorded by bedrock structures, morphological features and sedimentological criteria. Glacial varves. eskers and deltas are excellent records of paleoseismic events. Data from Sweden are presented. Faults, fractures and various types of sedimentary disturbances of Late Pleistocene and Holocene age frequently occur. It is concluded that the seismic activity was very intensive in connection with the peak rates of glacial isostatic uplift, and that this was a natural effect of the geodynamic processes operating.     

Tectonic stress,seismicity, and seismic hazard in the southeastern Carpathians

Intermediate-depth earthquakes in the Vrancea region occur in response to stress generation due to descending lithosphere beneath the southeastern Carpathians. In this article, tectonic stress and seismicity are analyzed in the region on the basis of a vast body of observations. We show a correlation between the location of intermediate-depth earthquakes and the predicted localization of maximum shear stress in the lithosphere. A probabilistic seismic hazard assessment (PSHA) for the region is presented in terms of various ground motion parameters on the utilization of Fourier amplitude spectra used in engineering practice and risk assessment (peak ground acceleration, response spectra amplitude, and seismic intensity). We review the PSHA carried out in the region, and present new PSHA results for the eastern and southern parts of Romania. Our seismic hazard assessment is based on the information about the features of earthquake ground motion excitation, seismic wave propagation (attenuation), and site effect in the region. Spectral models and characteristics of site-response on earthquake ground motions are obtained from the regional ground motion data including several hundred records of small and large earthquakes. Results of the probabilistic seismic hazard assessment are consistent with the features of observed earthquake effects in the southeastern Carpathians and show that geological factors play an important part in the distribution of the earthquake ground motion parameters.