油水两相渗流多孔介质弹性波传播动力学模型研究          下载免费PDF全文

刘静  李悦静  郑黎明  蒲春生 《地球物理学报》2019,62(9):3545-3556

弹性波在储层渗流场中的传播与衰减规律是研究波场强化采油动力学机理的重要基础.基于等效流体理论和饱和静态流体弹性波传播Biot理论，建立油水两非混相流体渗流条件下储层多孔介质中弹性波传播的动力学模型，通过算例求解与分析，发现含油水两相渗流储层多孔介质中同时存在着3种纵波P1、P2、P3和1种横波S；受频率和含水饱和度的影响，各波波速和品质因子呈现出不同变化规律，4种体波波速与频率、饱和度正相关，P1、P2波品质因子与饱和度正相关，P3和S波品质因子与饱和度负相关；最后，通过与传统静态弹性波模型结果对比，进一步分析了宏观渗流场对弹性波传播特征的影响规律，为揭示低频人工地震波辅助强化采油技术的动力学机理和工艺参数优化提供了重要理论依据.  相似文献   

基于动态图像变形的PP与PS波层位直接匹配   总被引：1，自引：1，他引：0       下载免费PDF全文

蒋雪珍  芦俊  王赟 《地球物理学报》2017,60(3):1106-1117

多分量地震资料的矢量偏移、多波地震资料的联合解释与反演均需要估算纵横波的速度比,实现纵波与转换横波在时间或深度域的匹配.基于DTW,本文实现了一种适用于PP与PS波直接匹配的动态图像变形算法.该算法分为三个部分:首先,使用二阶对称动态规划算法逐样点递归计算PP与PS波走时或深度的误差累积和;其次,在以误差累积和为目标函数的回溯阶段设定变形窗,并在纵横波速比约束的变形窗内递归回溯搜索匹配路径;最后,根据最大相关系数判定准则在匹配路径中确定最佳匹配路径,获得使PP与PS波匹配的拉伸或压缩时移量.利用所获得的拉伸压缩时移量计算纵横波速度比就可以实现PP与PS波之间的匹配.模型与实际陆上多分量地震资料测试结果表明:该方法具有较高的匹配精度,且对于信噪比、相似度较低的多分量地震资料,该方法也能产生较好的匹配效果.  相似文献   

基于扩展EL的大地测量报表系统     

陈正生  吕志平  李昌贵  王鹏 《四川测绘》2010,33(4):159-161

通过分析现有大地测量数据报表格式中存在的问题，以基于XML的大地测量数据接口文档为数据模型，建立了以Word文档为模板的EL引擎，使用户能够方便地对大地测量报表模板的样式和内容进行动态控制和修改，实现了数据库管理系统与报表系统、报表格式和数据内容的解耦，增加了报表的灵活性和扩展性。  相似文献   

动三轴试验滞回曲线的椭圆拟合分析     

毛远凤  叶庆东  沈宇鹏 《震灾防御技术》2017,12(4):743-750

采用正弦波形循环荷载动三轴试验获取土的动剪切模量和阻尼比的数据处理过程中通常存在两个困难:一是因为试验中存在各种噪声使滞回曲线椭圆形态不明显；二是椭圆拟合会因方法不当出现不收敛或者误差大等情况。为了在一定程度上克服第一个困难，本文将滤波技术引入到对应力应变时间序列的处理中来；为了更好地拟合滞回曲线椭圆，本文结合了主成份分析技术与椭圆的几何拟合方法，通过计算椭圆焦点位置、长半轴长度等来确定拟合椭圆，结果表明，该方法容易线性化且相对稳定，值得在动三轴数据处理中进行推广。  相似文献   

Where is my neighborhood? A dynamic individual-based definition of home ranges and implementation of multiple evaluation criteria     

《Applied geography (Sevenoaks, England)》2017

With the growing interest in studying characteristics of geographical context and its influence upon people, the concept of home range has been a focus of scholarly research. Home ranges are studied extensively across multiple disciplines, with literature supporting different operationalization techniques. This article argues that many of the existing approaches are not dynamic and versatile enough and do not provide reliable solutions for estimating individual home ranges. We additionally argue that many of current studies lack robust evaluation approaches. Recent evidences suggest that the usual approaches, which often exclusively rely on a single validation criterion, are not reliable and may be influenced by inferential errors. This study aims to tackle the exiting limitations in definition and operationalization of individual-based home range models and provide a more robust solution for their evaluation and comparison. Using data collected through public participation GIS we develop an applied, dynamic, and parametric model of individual home ranges. Subsequently, we propose multiple criteria comprising five validation hypotheses to evaluate model's effectiveness. We argue that application of this approach in evaluating spatial delimitation models can ameliorate the risk of biased validation resulting from inferential errors. The evaluation results indicate a substantial improvement in coverage of visited points compared to previously used static methods. Consequently, this paper draws a number of conclusions that can serve as guidelines for future research. This paper highlights the strengths and weaknesses of the proposed method and explains how it can be improved and employed in future studies investigating contextual effects on residents.  相似文献   

大比例尺地形图更新问题探讨     

张建辉  陈景新  罗永贤 《北京测绘》2010,(4):33-34,38

近年来,城市发展变化非常快,地形图更新滞后于城市发展,研究城市大比例尺地形图更新问题很有必要。本文阐述了地形图更新的方法,主要有数字摄影测量更新、利用高分辨率遥感影像更新、数字化测图更新以及借助其它项目资料进行更新等方法,并探讨了城市大比例尺地形图更新周期问题。  相似文献   

Hydrodynamic and dynamic analysis to determine the directional stability of an underwater vehicle near a free surface     

O. SaoutP. Ananthakrishnan 《Applied Ocean Research》2011,33(2):158-167

A theoretical methodology to determine the open-loop directional stability of a near-surface underwater vehicle is presented. It involves a solution of coupled sway and yaw equations of motion in a manner similar to that carried out for surface ships. The stability derivatives are obtained numerically through simulation of motions corresponding to planar motion mechanism (PMM) model tests. For the numerical simulation, a boundary-integral method based on the mixed Lagrangian-Eulerian formulation is developed. The free-surface effect on the vehicle stability is determined by comparing the results with that obtained for vehicle motion in infinite fluid. The methodology was used to determine the stability of the Florida Atlantic University’s Ocean EXplorer (OEX) AUV. The presence of the free surface, through radiation damping, is found to suppress unsteady oscillations and thereby enhance the directional stability of the vehicle. With effects of free surface, forward speed, location and geometry of rudders, location of the center of gravity etc. all being significant factors affecting stability, a general conclusion cannot be drawn on their combined effect on the vehicle stability. The present computational methodology is therefore a useful tool to determine an underwater vehicle’s stability for a given configuration and thus the viability of an intended mission a priori.  相似文献   

On dynamic coupling effects between a spar and its mooring lines     

Xiaohong Chen  Jun Zhang  Wei Ma 《Ocean Engineering》2001,28(7):79

The responses of a spar constrained by slack mooring lines to steep ocean waves and tensions in the mooring lines are simulated using two different numerical schemes: a quasi-static approach (SMACOS) and a coupled dynamic approach (COUPLE). The two approaches are the same in computing wave loads on the structure. Their difference is in modeling dynamic forces of mooring lines; that is the dynamic forces are included in the computation of COUPLE but neglected in SMACOS. The numerical simulation is examined against the laboratory measurements of the JIP Spar in a water depth of 318 m. The dynamic coupling effects between the JIP Spar and its mooring lines in different water depths (318, 618 and 1018 m) are investigated by the comparison of numerical simulations obtained using the quasi-static and coupled dynamic approaches. It is found that the damping of mooring lines reduces the slow-drift surge and pitch of the Spar, especially in deep water. The reduction in the amplitude of slow-drift surge can reach about 10% in a water depth of 1018 m. The tension in mooring lines may greatly increase in the wave frequency range when dynamic forces in mooring lines are considered. The mooring-line tension in the wave frequency range predicted by the coupled dynamic approach can be eight times as great as the corresponding prediction by the quasi-static approach in a water depth of 1018 m. This finding may have important implications for the estimation of the fatigue strength and life span of the mooring lines deployed in deep water oceans.  相似文献   

Dynamic analysis of a vertical plate exposed to breaking wave impact     

M. Salih Kirkgoz  A. Kamil Tanrikulu  Cengiz Dündar 《Ocean Engineering》2004,31(13):2308-1635

From the experimental studies in recent years, it has become known that when a wave breaks directly on a vertical faced coastal structure, high magnitude impact pressures are produced. The theoretical and experimental studies show that the dynamic response of such structures under wave impact loading is closely dependent on the magnitude and duration of the load history. The dynamic analysis and design of a coastal structure can be succeeded provided the design load history for the wave impact is available. Since these types of data are very scarce, it is much more convenient to follow a method which is based on static analysis for the dynamic design procedure. Therefore, to facilitate the dynamic design of a vertical plate that is exposed to breaking wave impact, a multiplication factor called “dynamic magnification factor” is herein presented which is defined as the ratio of the maximum value of the dynamic response to that found by static analysis. The computational results of the present study show that the dynamic magnification factor is a useful ratio to transfer the results of static analysis to the dynamic design of a coastal plate for the maximum impact pressure conditions of p_max/γH₀≤18.  相似文献   

随机Petri网在地震应急协同能力定量评价与动态分析中的应用          下载免费PDF全文

樊海刚  郭红梅  张莹  赵真 《中国地震》2022,38(2):248-259

地震应急是一个复杂动态的过程,需要各部门协同配合方能高效开展应急工作。本文通过调研分析历史地震应急处置案例,提出了Ⅰ、Ⅱ级应急响应下多主体地震应急协同的一般流程,构建了相应的随机Petri网模型,并基于Petri网可能出现的状态集同构马尔科夫链,在计算各应急状态稳定概率的基础上,定量评价应急协同能力。同时,将应急过程中利用率高的变迁所对应的应急行为,作为应急处置的关键环节。通过调整各关键环节的应急速率,进一步对应急协同能力进行动态分析,进而提出有效提高应急协同联动能力的相关建议,为科学开展地震应急处置工作提供支持。  相似文献