一种维护线状地物基本单元属性逻辑一致性的平差方法

通过分析线状地物基本单元基本平差准则和方法,细化了变更行为并分析每一种变更类型的数据流向,设计并实现了一种能严格维护基本单元逻辑一致性的平差算法,并在实际应用系统中得到了验证。     

Selection of time step for pseudodynamic testing

Although the step degree of nonlinearity has been introduced to conduct basic analysis and error propagation analysis for the pseudodynamic testing of nonlinear systems, it cannot be reliably used to select an appropriate time step before performing a pseudodynamic test. Therefore, a novel parameter of instantaneous degree of nonlinearity is introduced to monitor the stiffness change at the end of a time step, and can thus be used to evaluate numerical and error propagation properties for nonlinear systems. Based on these properties, it is possible to select an appropriate time step to conduct a pseudodynamic test in advance. This possibility is very important in pseudodynamic testing, since the use of an arbitrary time step might lead to unreliable results or even destroy the test specimen. In this paper, guidelines are proposed for choosing an appropriate time step for accurate integration of nonlinear systems. These guidelines require estimation of the maximum instantaneous degree of nonlinearity and the solution of the initial natural frequency. The Newmark explicit method is chosen for this study. All the analytical results and the guidelines proposed are thoroughly confirmed with numerical examples.     

宁夏香山群徐家圈组基本沉积单元

报道了宁夏香山群徐家圈组基本组成单元,即由细砂岩－粉砂岩－页岩构成的沉积序列,并将该沉积序列划分为密度流沉积层（Ⅰ）、牵引流沉积层（Ⅱ）和悬浮沉积层（Ⅲ）,进而探讨其成因。结果表明：①层Ⅰ主要由细砂岩和粉砂－细砂岩组成,且在不同厚度层之间无明显的粒度分异;②徐家圈组岩性系列中明显缺失细砂质粉砂岩,而这种缺失正好构成了层Ⅰ和层Ⅱ之间的粒度中断;③层Ⅱ发育两组交错层理,第一组是平行层理、准平行层理、复合流层理和小型丘状交错层理,第二组是单向交错层理、双向交错层理和平行层理;④层Ⅲ中的薄层泥晶石灰岩具有不平整的底面并在侧向上呈现出长的透镜状。结合相关的浊流沉积研究成果,综合分析上述结果,可得出以下结论：①层Ⅰ可能为具有高悬浮负载降落速率的高密度衰减流沉积形成;②层Ⅱ可能受内波、内潮汐作用的控制;③层Ⅲ可能以深海、半深海垂直降落沉积为主,并辅以缓慢的平流;④沉积时的浊流可能具有双层结构。     

A practical estimation of Clark IUH parameters using root selection and linear programming

The values of the parameters of the Clark instantaneous unit hydrograph (IUH) are often relying on the subjective decision of the researcher, which leads to large variations of their values. Therefore, an objective method minimizing the subjective judgement in the IUH modelling procedure while providing a reduced range of acceptable values is proposed. The proposed method uses a basin average IUH to mitigate the robustness problem of the Clark IUH parameters. Using linear system theory, the z‐transform is applied to the average IUH and then the IUH polynomial is factored into the recession and time‐area curve (TAC) components based on a convolution relation between the Clark IUH parameters. During this calculation, the root selection method was adopted to verify the storage coefficient R from the recession component and a linear programming technique was applied for determining the TAC for the basin of interest. The Wi River basin was used to test the applicability of the proposed method. The results showed that the components of a single reservoir and the TAC for Clark IUH were separated effectively, and acceptable values for the parameters were obtained. Copyright © 2011 John Wiley & Sons, Ltd.     

Hilbert-Huang变换方法研究进展

自然过程大都具有非线性非平稳性,一种自适应数据分析方法对于分析这些过程来说是极其必要的。Huang于1998年创立的H ilbert-Huang变换(HHT)就是这样一种自适应性非线性非平稳数据分析方法,该方法由经验模态分解(EMD)和H ilbert变换两部分组成。文中首先详细解释了HHT的思想和基本理论;然后介绍了该方法近期的重要研究进展,列举了其在科研和工程领域的应用;最后,对方法中仍然存在的问题进行了讨论。     

煤田岩溶塌陷正演模拟及属性应用

岩溶陷落柱在华北煤田中广泛分布,严重影响矿井的设计和生产。笔者通过建立正演模型,利用模型数据的偏移结果进行地震属性的提取与分析。对部分地震属性的分析和对比表明,溶洞的横向尺度大小在振幅类、频率类、相位类属性都有较好的反应,纵向尺度可由谱分解属性定量。     

基于神经网络的聚类分析在储层流动单元划分中的应用

以苏里格气田盒8段为研究对象,在细分层和精细沉积学研究基础上,通过对关键井详细研究,以流动层段指标为储层流动单元划分标准,将目的层分为3类流动单元。通过相关性分析结合专家经验,从诸多电性、物性、岩性等参数中优选出表征流动单元的10个特征变量作为预测模型的输入,应用基于神经网络算法的聚类分析方法建立储层流动单元非线性识别模型。通过对其他关键井的回判预测表明,建立的流动单元预测模型可以更全面地考虑各类地质因素与流动单元之间的结构性复杂映射关系,气井产能与流动单元具有较高的对应关系,为气田精细描述与开发井网的优化部署提供可靠基础。     

基于灰色定权聚类的微观水驱油模型实验特低渗透储层流动单元划分及评价

为研究微观水驱油模型流动单元划分及评价的可行性和效果,应用灰色定权聚类方法,以吴起油田X井区特低渗透长63储层25块样品为例,采用真实砂岩微观水驱油模型实验,以测得的渗透率、水驱前含油饱和度、启动压力、1 PV驱油效率以及孔隙度5项参数为基础,将样品划分为Ⅰ类、Ⅱ类和Ⅲ类流动单元.Ⅰ类、Ⅱ类和Ⅲ类流动单元分别与水下分流...     

PH油气田H组储层流动单元的识别划分与剩余油分布研究

随着油气田勘探开发进入中后阶段,高含水和低渗透成为继续有效开发的限制因素,使得剩余油的区域分布呈现分散化和边缘化的状态,增加了挖潜难度.为解决这一难题,20世纪80年代C.L.Hearn提出了流动单元的概念,流动单元的研究规模介于砂体规模与微观孔隙规模之间,是油藏精细描述和表征的最基本单元,其准确的识别和划分对于合理评价储层,深化储层非均质性认识,提高油藏数值模拟的精度,确定剩余油分布和调整挖潜对象具有重要意义.     

国际海道测量标准比较研究

为适应海道测量数据应用领域不断扩大和用户要求不断提高的需求,国际海道测量组织和世界海道测量技术发达国家相继发布了各自的新版海道测量规范和标准.将我国海道测量规范与国际海道测量标准在测量的分类与质量基准、水深测量技术要求以及其他测量标准等方面进行比较详细的分析比较,指出了我国海道测量规范的不足和需要改进的问题,旨在推进我...