时移地震监测水驱前沿的方法和应用研究

油藏开发过程的有效监测是合理开采油藏和提高采收率的关键之一.本文根据水驱油藏流体变化的基本规律以及其他实验和统计结果,讨论了长期注水开采油藏储层物性变化及其引起的弹性参数变化和地震响应变化特征,明确了水驱前沿的概念,提出了基于差异振幅和奇异值分析的时移地震监测水驱前沿方法.理论模型研究表明该方法是可行的.通过对东部地区某油田的两次三维地震数据处理、分析,确定了水驱前沿的位置,后钻的两口井证实了预测结果的准确性和方法的有效性.研究结果还表明,通过水驱前沿的监测并结合初期油藏描述的结果,时移地震可以很好地预测长期水驱油藏剩余油的分布.     

分区连续函数的Radon变换的高精度反演法

Ｒａｄｏｎ变换及其反演是ＣＴ技术的数学基础,常用的反演算法虽然在函数比较光滑的情况下都能获得较满意的结果,但当函数有较强的奇性时精度就比较差．对函数在每一子区域中是光滑,但在不同于区域交界处有间断的情况,本文给出了有高精度的反演算法．     

超弦理论中的宇宙波函数

本文讨论了超弦理论中的宇宙波函数，使用Ｖｉｌｅｎｋｉｎ的边界条件，我们得到了膨胀子场Ｄ的值给定时宇宙标度因子ａ的几率分布。我们还得到了宇宙自发成核时，经典宇宙的标度因子的最小值为Ｐｌａｎｃｋ长度的数量级，这说明量子效应能阻止宇宙塌缩到奇点。     

利用小波变换降低环境噪声对测深数据的影响

本文针对测深数据在环境噪声处理中存在的问题,利用海底信号和环境噪声小波变换模的极大值在不同尺度下具有不同的传播特性,提出了利用多尺度小波变换分析测深数据的方法,从而达到降低环境噪声对测深数据影响的目的。通过实验表明该方法具有较好的效果。     

海域流动点外部扰动引力无奇异计算模型

针对海域重力场变化特征和远程飞行器机动发射保障应用需求,本文分析研究了地球外部空间扰动引力三类传统计算模型的技术特点及其适用性,指出了采用表层法作为海域流动点扰动引力计算模型的合理性及需要解决的关键问题,分析论证了空中扰动引力计算对地面观测数据的分辨率和精度要求,提出通过引入局部积分域恒等式变换、局域泰勒级数展开和非网格点内插方法,消除表层法计算模型积分奇异性固有缺陷的研究思路,进而推出了适合于海域流动点应用的扰动引力无奇异计算模型,较好地满足了全海域和全高度段对局部扰动重力场快速赋值的实际需求.以超高阶全球位模型EGM2008作为标准场,通过数值计算验证了无奇异计算模型的可行性和有效性,在重力场变化比较剧烈的海沟区,该模型的计算精度优于2×10^-5m·s^-2.

     

Upscaled modeling of well singularity for simulating flow in heterogeneous formations

Subsurface flows are affected by geological variability over a range of length scales. The modeling of well singularity in heterogeneous formations is important for simulating flow in aquifers and petroleum reservoirs. In this paper, two approaches in calculating the upscaled well index to capture the effects of fine scale heterogeneity in near-well regions are presented and applied. We first develop a flow-based near-well upscaling procedure for geometrically flexible grids. This approach entails solving local well-driven flows and requires the treatment of geometric effects due to the nonalignment between fine and coarse scale grids. An approximate coarse scale well model based on a well singularity analysis is also proposed. This model, referred to as near-well arithmetic averaging, uses only the fine scale permeabilities at well locations to compute the coarse scale well index; it does not require solving any flow problems. These two methods are systematically tested on three-dimensional models with a variety of permeability distributions. It is shown that both approaches provide considerable improvement over a simple (arithmetic) averaging approach to compute the coarse scale well index. The flow-based approach shows close agreement to the fine scale reference model, and the near-well arithmetic averaging also offers accuracy for an appropriate range of parameters. The interaction between global flow and near-well upscaling is also investigated through the use of global fine scale solutions in near-well scale-up calculations.     

亮点周围的衍射模式

将衍射问题研究中的回波解析奇性归结为探讨含参量的振荡积分的渐近性态问题,并利用广义函数的算子理论,以十分简捷的方式给出了上述振荡积分的稳定位相公式,以及结合Ｔｈｏｍ理论逐一地算出非退化奇点、岐点和脐点周围的衍射模式．     

Wavelet evaluation of the Stokes and Vening Meinesz integrals

The wavelet transform is a powerful tool in evaluating some singular geodetic integrals. Due to its localization properties in both the time (space) and frequency (scale) domains, and because the kernels of some geodetic integrals have singular points and decay smoothly and quickly away from the singularities, many wavelet transform coefficients of the kernels become zeros or negligible, and only a small number of wavelet transform coefficients are significant. It is thus possible to significantly compress the kernels of these integrals on a wavelet basis by neglecting the zero coefficients and the small coefficients below a certain threshold. Therefore, wavelets provide a convenient way of efficiently evaluating these integrals in terms of fast computation and savings of computer memory. A modified algorithm for the wavelet evaluation of Stokes' integral is presented. The same modified algorithm is applied to the evaluation of the Vening Meinesz integral, whose kernel has a stronger singularity than does Stokes' kernel. Numerical examples illustrate the efficiency and accuracy of the wavelet methods.Acknowledgments.The author express their sincere thanks to Dr. Salamonwicz for providing his PhD thesis. E-mail correspondence between the authors and Dr. Barthelmes and Dr. Benciolini contributed to the work. R. Benciolini and the other two anonymous reviewers are thanked for their constructive comments. Support for this research was provided by research grants to Dr. Sideris from the Natural Sciences and Engineering Reserch Council of Canada (NSERC) and the Geomatics for Informed Decisions (GEOIDE) Network of Centres of Excellence. The MATLAB Wavelet Toolbox package was used as the platform to develop the software in this project.     

成都双流机场的奇点雾及其预报

在考查了成都双流机场实际天气现象以及雾的多极变化的基础上，提出了奇点雾的概念，并从理论上分析了其发生的物理机制，认为弱冷平流是其发生的主要原因，并提出了预报方法。     

一维有耗散波动方程的奇性分析与小波

对系数有强奇性（间断）的波动方程,用通常的线性化简的方法时往往会将数值小但奇性强的项略去,导致结果严重失真。利用小波变换这一工具,可以在化简时保留奇性的主要部分,使所得的结果从奇性分析的观点看来更为精确。此方法曾被用来处理系数有间断的一维波动方程,得到了与精确解的奇性主部完全一致的解．在本文中,我们改进了用小波变换作奇性化简的方法,对系数有间断的一维有耗散波动方程求得了与精确解奇性主部完全一致的解。这说明利用小波分析作奇性化简的方法对高频近似及奇性分析问题是普遍适用的．