玛湖-盆1井西复合含油气系统二叠系地下水动力场的形成与演化

油气运聚及分布和地下水动力场的形成与演化密切相关,随着盆地的演化,地下水动力场也经历了形成、发展和消亡的过程.对水化学、水动力分布特征研究表明,玛湖-盆1井西复合含油气系统二叠系的现今水动力场由于达巴松凸起而呈现分割性,形成玛湖和盆1井西2个独立的水动力体系,欠压实的存在使凹陷内仍然保持离心流特征,而盆地西北缘则是大气水下渗向心流区.研究区二叠系的水动力场演化具有南移特征.     

Assessing flood risk in Baiyangdian Lake area in a changing climate using an integrated hydrological-hydrodynamic modelling

ABSTRACT

Flood-risk is affected by both climatic and anthropogenic factors. In this study, we assess changes in flood risk induced by a combination of climate change and flood prevention sets in the Baiyangdian (BYD) Lake area of China. Extreme storm events are analysed by the bias-corrected climate data from global climate models. A hydrological model is implemented and integrated with a hydrodynamic model to assess flood risk under three scenarios. The streamflow into the BYD was validated against historical flash-flood events. The results indicate that the changing climate increased extreme precipitation, upstream total inflow and the flood risk at the core region of Xiong’an New Area (XNA), the newly announced special economic zone in the BYD area. However, flood prevention measures can effectively mitigate the climatic effect. The research highlights the severe flash-flood risk at BYD and demonstrates the urgent need for a climate-resilient plan for XNA.     

河口湾水动力环境对滩涂利用的累积响应——以珠江口伶仃洋为例

为揭示河口湾水动力环境对滩涂利用的累积响应过程,以珠江口伶仃洋河口湾为例,基于潮波数学模型和潮流数学模型,研究了1981年以来湾内进出潮量、分潮振幅和潮流流速的累积变化。结果表明:相对于1981年,2018年岸线条件下伶仃洋湾口断面涨落潮量累积减少4.9%~6.0%、内伶仃断面涨落潮量累积减少9.0%~12.8%、深圳湾断面涨落潮量累积减少17.8%、南沙断面涨落潮量累积减少5.0%~6.3%;伶仃洋M₂分潮振幅呈增加趋势,振幅增幅由南向北增加,潮波由南向北变形进一步加剧;伶仃洋最大可能潮差变化与M₂分潮振幅变化趋势一致,潮汐性质没有发生变化;伶仃洋潮流流速总体减小,西岸流速减幅高于东岸,湾顶附近流速略有增加。     

基于HBP本构模型的泥石流动力过程SPH数值模拟

本构模型是描述泥石流流变特性的关键,也是决定其动力过程数值模拟准确性的核心问题之一。泥石流流体属多相混合物,现有的研究已证实其存在剪切增稠或剪切变稀的现象,传统基于Bingham及Cross线性本构关系的数值模型难以准确描述泥石流流变特性。文中探讨了Bingham模型在低剪应变率下的数值发散问题,在光滑粒子流体动力学（SPH）方法框架上建立了整合Herschel-Bulkley-Papanastasiou(HBP）本构关系的稀性泥石流动力过程三维数值模型。相比传统基于浅水波假设的二维数值模型,所述方法从三维尺度建立SPH形式下的泥石流浆体纳维?斯托克斯方程并进行数值求解,可获取泥石流速度场时空分布及堆积形态,同时采用HBP本构关系描述泥石流流变特性,能在确保数值收敛的前提下反映泥石流流体在塑性屈服过渡段及大变形状态下应力?应变的非线性变化。为验证提出方法的合理性,结合小型模型槽实验观测进行了对比,结果表明数值模拟与实测结果基本吻合。     

复杂河网水动力数值模型

利用汊点水位预测-校正(junction-point water stage prediction and correction,JPWSPC)法处理缓流河网汊点处的回流效应,采用Preissmann格式离散Saint-Venant方程组,并采用Newton-Raphson方法求解非线性离散方程,构建了非恒定河网水动力模型.模型既无需特殊的河道编码,又避免了建立和求解总体矩阵.与常用的分级解法模型相比,保留了其既适用于树状又适用于环状河网的优点,同时克服了分级解法需要建立和求解河网总体矩阵的缺点,显著提高了稳定性和计算效率.     

A closed form analytical solution for two‐dimensional plane strain consolidation of unsaturated soil stratum

This paper discusses the excess pore‐air and pore‐water pressure dissipations and the average degree of consolidation in the 2D plane strain consolidation of an unsaturated soil stratum using eigenfunction expansion and Laplace transformation techniques. In this study, the application of a constant external loading on a soil surface is assumed to immediately generate uniformly or linearly distributed initial excess pore pressures. The general solutions consisting of eigenfunctions and eigenvalues are first proposed. The Laplace transform is then applied to convert the time variable t in partial differential equations into the Laplace complex argument s. Once the domain is obtained, a simplified set of equations with variable s can be achieved. The final analytical solutions can be computed by taking a Laplace inverse. The proposed equations predict the two‐dimensional consolidation behaviour of an unsaturated soil stratum capturing the uniformly and linearly distributed initial excess pore pressures. This study investigates the effects of isotropic and anisotropic permeability conditions on variations of excess pore pressures and the average degree of consolidation. Additionally, isochrones of excess pore pressures along vertical and horizontal directions are presented. It is found that the initial distribution of pore pressures, varying with depth, results in considerable effects on the pore‐water pressure dissipation rate whilst it has insignificant effects on the excess pore‐air pressure dissipation rate. Copyright © 2015 John Wiley & Sons, Ltd.     

Particle image velocimetry and numerical simulations of the hydrodynamic characteristics of an artificial reef

This article reports a particle image velocimetry study and the comparative results of a numerical simulation into the hydrodynamic characteristics around an artificial reef.We reveal the process of flow separation and vortex evolution,and compare the force terms generated by our artificial reef model.The numerical simulation agrees well with experimental results,showing the applicability of computational fluid dynamics to the hydrodynamics of an artificial reef.Furthermore,we numerically simulate the hydrodynamics of the reef model for seven velocities.The results show that the drag coefficient is approximately 1.21 in a self-modeling region for Reynolds numbers between 2.123×104and 9×104.Therefore,the upwelling height and current width of the flow field do not change significantly when the inflow velocity increases.Our study indicates that computational fluid dynamics can be applied to study the hydrodynamics of an artificial reef and offer clues to its construction.     

某傍河污染场地排污河与地下水水力联系模拟研究

为研究常见地表排污河对地下水造成的影响,选择安徽省淮北市濉河某傍河区域进行研究。在对研究场地开展野外调查、抽水试验、微水试验等工作的基础上,从水动力学角度对研究场地地下水进行系统研究。应用Processing Modflow建立了该研究场地的水文地质模型,根据各均衡区间水量交换情况揭示了排污河、深浅含水层间的水力联系状况。模拟结果表明,排污河与浅层含水层之间没有明显的水力联系;深、浅含水层之间的水力联系微弱。     

近三十年天津市地热大规模开发热储动态特征研究

天津是我国较早大规模开发深层地热的地区之一,经过30多年的持续开采回灌,对深部热储特征有无影响,是否引起了资源枯竭、水质恶化以及热储温度下降等环境问题,一直是社会关注的焦点。本文系统收集了1992年以来天津市地热开发过程中的不同热储层热水开发利用量、回灌量、水位、水质、水温等近30年的时间序列监测资料,通过垂向及横向对比,对地热持续开发30年来天津市不同地区不同热储层的热水动态特征进行了分析。结果表明,天津市各热储层地热流体的主要化学组分基本稳定,多年来无明显变化,地热采灌系统尾水回灌不会从根本上改变地热流体的原始化学特征,但深大断裂作为热流通道引起的顶托补给,会对上层热储水质造成一定的影响;随着近年来天津市回灌工作力度不断加大,大部分热储水位下降幅度减缓或出现回升,热储的温度没有明显的升高或降低的趋势,但回灌井热储段经过非供暖期的恢复无法达到最初的温度,呈逐年下降趋势。未来持续采灌条件下,回灌井筒的“冷堆积”及采灌井的优化调配应是重点关注的问题。     

连云港近岸海域沉积物特征与沉积环境

根据连云港地区近岸海域的表层沉积物分析结果,运用Flemming的三角图示对沉积环境进行划分,并在此基础上结合沉积物结构、地形及水动力条件,探讨了研究区域沉积物特征及沉积环境。结果表明,研究区域沉积物以潮流作用为主,沉积环境可划分为近岸和远岸沉积环境。近岸沉积环境,由于潮流由外海向岸逐渐减小,向上部搬运的泥沙粒径越来越小,因此该区域泥沙颗粒较细,主要为黏土质粉砂和砂-粉砂-黏土;远岸沉积环境,潮流流速很大,可掀动并搬运较细颗粒泥沙,使得远岸区域有进一步粗化的趋势。