纳微米聚合物调驱渗流理论模型研究及其应用

纳微米聚合物作为一种新型的逐级调驱剂,可在油层深部发生物理和化学变化,实现液流改向。根据纳微米聚合物调驱渗流特点,此文建立了三维三相三组分纳微米聚合物调驱数学模型,考虑了对流扩散和调驱渗流特性,采用隐压、显饱、隐浓的差分方法求解数学模型,并编制了相应的数值模拟软件。对纳微米聚合物调驱矿场试验区进行了数值模拟研究,分析了纳微米聚合物浓度、段塞长度、段塞组合对开发指标的影响,并制定合理的注入方案,实施后达到了增油降水和提高采收率的目的,与数值模拟预测指标基本符合。     

高温泡沫驱油技术的数学模型及应用

在对高温泡沫驱油作用机理进行研究的基础上,建立了高温泡沫驱油数学模型.该模型充分考虑了对流、弥散及表面活性剂损失等机理.对该模型进行了数值求解,模型采用自适应隐式方法求解.将模型结果与国外软件进行了对比,证明该模型及算法的正确性及可靠性.利用该模型讨论了泡沫注入参数对驱油效果的影响,随着泡沫剂浓度的增加,原油产量增加,最佳注入浓度应为0.6wt%;泡沫注入时机和气液比应根据油藏条件,进行优化.     

弱凝胶调驱降维数值模拟方法研究

目前用于弱凝胶调驱的化学驱软件大多存在计算速度慢、数值弥散现象严重的问题,为了提高弱凝胶调驱数值模拟的速度和精度,提出了降低维数的模拟方法。利用追踪流线的方法,将弱凝胶调驱的三维渗流问题,转化为沿流线计算饱和度的一维问题,大大降低了求解饱和度方程组中方程的数目,从而提高了计算速度。利用该方法,模拟了玉门老君庙油田一个试验井区的水驱开发历史,优化了弱凝胶调驱的注入浓度、注入速度及注入体积等参数,并预测了弱凝胶调驱的动态,预测该方案可提高采收率7.6%。     

考虑水驱油藏润湿性变化的数值模拟方法

注水开发过程中岩石润湿性的变化对水驱效率和剩余油的分布影响较大，然而目前通用的数值模拟软件未能将其考虑在内。本文根据已有结论及研究成果，提出了考虑岩石润湿性变化的方法。主要利用相对渗透率的变化来表征润湿性的变化，根据含水饱和度的变化选择相应的相对渗透率曲线，在黑油模型的基础上建立能反映长期水冲刷后油藏岩石润湿性变化的数学模型，开发研制了三维三相下考虑储层润湿性变化的数值模拟软件，结合胜利油田典型油藏，进行了数值模拟研究。结果表明：岩石润湿性变化对水驱效果的影响与开发初期岩石润湿程度有关，对于偏亲水油藏，考虑润湿性变化后计算的采出程度有所减小，而亲油油藏考虑润湿性变化后计算的采出程度有所增加。     

辽河油田锦16块第一层系油藏开发调整数值模拟

本文应用根据水动力学原理建立油藏内三维三相流动模型所编制的计算机软件，对辽河油田具有多年开发历史的锦１６块第一层系进行数值模拟研究。采用三种不同方案预测到２００３年时的开发指标，对油田开发调整具有很强的指导作用。     

天然气超音速分离流喷管的特性研究

建立了天然气超音速分离流喷管的三维模型,应用流体动力学软件CFX对喷管的内部流场进行数值模拟,得到内部流场的马赫数、温度、速度和压力分布云图,研究了喷管喉部结构参数对喷管内部流场的影响,揭示了喉部结构参数变化对超音速流动的影响机制。     

刀具破岩机制研究现状及发展趋势

在分析大量文献的基础上,从理论模型、物理试验和数值模拟三个方面,对近些年国内外刀具破岩规律研究进展情况进行归纳和总结,并对各种研究方法的适用性、优缺点进行了评述,侧重论述了数值模拟研究进展,探讨了当前研究热点问题,包括节理岩体中的破岩规律、开裂准则、动力破岩和三维数值模拟研究等。总体来看,有关刀具破岩机理的研究取得了长足进展,尤其是数值计算从不同层次上揭示了刀具破岩机制,包括滚刀作用下岩石裂纹扩展规律、滚刀与岩石的相互作用力学模型、材料力学参数、滚刀作用方式、围岩地应力以及刀具几何参数等因素对破岩效率的影响,数值计算方法极大地促进了刀具破岩规律的深入研究;最后总结了当前刀具破岩受力模型、动态加载与三维模拟等面临的挑战问题。     

预应力锚固机理数值仿真分析研究

本文应用传统的岩石力学模型与方法，以及岩体损伤模型、摩擦接触模型、无限边界模型等新模型与方法，以大型岩土工程数值分析软件ＦＩＮＡＬ为研究手段，对预应力锚固机理与效果进行了大量系统、深入的数值仿真分析。选取了四个不同的三维非线性数值模型，分别进行多参数、多层次对比数值分析与研究，在数值分析的基础上提出了一系列指导预应力锚固设计与施工的重要结论与计算公式，并从传统的岩体强度理论、岩体弹塑性理论、岩体断     

基于FLOW 3D的山丘区小流域山洪演进三维数值模拟研究

由于山洪灾害涉及气象学、水文学、水力学及动力学等多个学科,在演进机理研究方面还不够全面.为研究山洪灾害演进机理,以毛公洞小流域为例,借助FLOW 3D软件进行三维数值模拟,建立了河道两岸300m范围内实体地形三维数值模型,对山洪灾害暴发的动态过程进行了模拟计算,在此基础上分析了山洪灾害演进机理,该结果对后续山洪灾害成灾机理及演变分析具有一定的参考意义.     

多弯道溢洪道水力特性数值模拟研究

文中在物理模型试验的基础上,对多弯道溢洪道进行了数值模拟研究。采用FLUENT软件,引入适用于分层两相流的流体体积分数(VOF)模型求解自由水面曲线,成功地对龙屯水库多弯道溢洪道进行了三维紊流数值模拟,得到了自由水面、溢洪道底板压力、断面流速大小和三维流场的分布规律,并将数值模拟结果与试验结果进行了分析对比,两者基本吻合。试验结果表明:合理的选择数值模拟模型及参数,可以很好地模拟水流流态,可为工程所用。     

SEEPAGE ABILITY OF HIGH-PRESSURE HOT COMPOSITE FOAM IN POROUS MEDIA

The technology of hot composite foam displacement refers to the injection of high-temperature flue gas and foaming and stabilizing agent into wells with a certain concentration,and after meeting the formation water,a composite foam system is formed in the reservoir.This foam displacement technology involves thermal function and so is related to nitrogen,carbon dioxide and foam flooding characteristics.After analyzing seepage flow law of hot composite foam system,seepage flow experiment of composite foam und...     

MATHEMATICAL MODEL OF THE MICROBIAL FLOODING

NOMENCLATUREμ———growthrate ,h- 1;μmax ———maximum growthrate (gainedinthelaboratory) ,h- 1;Ks ———saturationconstant (gainedinthelab oratory) ;ρs ———concentrationofsubstrate ,gL- 1;i———componentiofthematrix ;YGi ———amountofthenewproducedmicrobesafterconsumingunitmassofcomponenti (gainedinthelaboratory) ,g/ g ;mi ———amountofcomponenti———consumedforthemicrobemetabolism (gainedinthelabora tory) ,h- 1;R———consumptionrate ,h- 1;C′i ———productionrateofmetabolic …     

The effects of drying and re‐flooding on nutrient availability in ephemeral deflation basin lakes in western New South Wales,Australia

We examined the response of nutrient concentrations to the drying and re‐flooding of ephemeral deflation basin lakes (EDBL) in western New South Wales, Australia. As lakes dried total nitrogen (TN) and total phosphorus (TP) concentrations increased. TN concentrations increased more quickly and TP concentrations increased more slowly than could be attributed to evaporation alone. This suggested that additional nitrogen was being sequestered from the atmosphere or sediments and that some phosphorus loss to the sediments was occurring. Concentrations of nitrogen oxides (NOx) and filterable reactive phosphorus (FRP), however, declined as lakes dried, suggesting a tighter coupling of nutrient release and uptake mechanisms. Inorganic nutrient concentrations rose sharply in response to re‐flooding in all lakes. Evidence is provided to suggest that post‐flood nutrient pulses are the net result of both riverine inputs and sediment releases and that the relative significance of either may be influenced by regulation. Copyright © 2002 John Wiley & Sons, Ltd.     

鄂北地区水资源配置工程夹河套段倒虹吸防护研究

针对鄂北地区水资源配置工程的唐白河夹河套段倒虹吸工程防护问题,建立了唐河、白河一维及夹河套区域二维水动力学耦合模型,综合考虑溃堤和漫堤等多种极端不利因素,计算分析了不同设计洪水标准下唐河和白河堤防溃决、漫溢等条件下的洪水影响范围及程度。选择最不利方案进行了无防护和有防护等不同情况下的物理模型冲刷试验,研究溃漫堤洪水对工程线路的冲刷影响。数学模型计算成果表明:溃堤洪水大流速主要分布在溃口附近区域,溃口位于工程线路附近时对工程的冲刷影响较严重。综合数学模型计算和物理模型试验结果,根据格栅石笼的冲刷变形程度及范围、冲刷坑范围及抗冲流速影响范围,确定了工程沿线不同的防护等级与范围,为夹河套倒虹吸工程防护方案设计提供支撑和依据。     

考虑油藏储层参数变化的数值模拟研究

油田在注水开发过程中,储层的物性参数、流体性质等都在不断发生变化,本文根据胜坨油田沙二1-2的储层参数随含水变化的基本规律,对黑油模型数值模拟软件进行了改进,使之能够考虑油藏储层参数的变化,并应用软件分析了参数变化对开发效果的影响。改进后的软件提高了数值模拟精度,使计算结果更能真实的反映地下流体分布情况,为改善油藏的开发效果,采取有针对性的开发措施,提供了重要依据。     

The effects of short‐term inundation on carbon dynamics,microbial community structure and microbial activity in floodplain soil

A mesocosm study was carried out to determine whether flooding affected soil microbial structure and function. Over a 24 day period soils were either flooded or remained dry and changes in the microbial community structure, microbial metabolic activity (determined by looking at soil respiration rates and exo‐enzyme activity), community level physiological profiles and soil carbon speciation were examined. Flooding induced significant changes in the microbial community structure and increased soil respiration and enzymatic degradation rates. Shifts occurred in carbon speciation after flooding and increases in ‘labile’ carbon fractions were observed. The duration of flooding was also important for carbon dynamics and microbial community structure. Based on the results of the mesocosm experiment a conceptual model of floodplain soils response to flooding over time was formulated. The findings of this mesocosm study illustrate the importance of flooding to floodplain soil functioning. Copyright © 2010 John Wiley & Sons, Ltd.     

Effects of flooding regime upon the decomposition of Eichhornia azurea (Sw.) Kunth measured on a tropical,flow‐regulated floodplain (Paraná River,Brazil)

Decomposition of macrophytes is an important process in river‐floodplain systems, especially in the Upper Paraná River floodplain, given that this ecosystem receives high inputs of detritus from this vegetation. Release of nutrients by decomposition is essential in this floodplain because it is located downstream from a reservoir chain where nutrients are being trapped. Water level fluctuations are considered one of the most important aspects that affect macrophyte decomposition. Anthropogenic alterations, such as the control of flooding regimes, observed in this floodplain, could change the dynamic of this process. To evaluate the influence of the hydrological cycle upon the decomposition of Eichhornia azurea (an aquatic macrophyte that has high biomass values in this ecosystem), litter bags with senescent leaves and petioles of this plant were submitted to four different flooding treatments, which differed in time of flooding and exposure to dry conditions. The decomposition rates and the detritus chemical composition (nitrogen and phosphorus concentrations) were measured over 113 days. There were significant effects of the flooding treatments and time upon all parameters. The materials that decomposed with flood conditions showed the greatest decomposition rates. The quality of the detritus seems to be highly linked with the flooding regime, showing highest releases of phosphorus in the submerged treatments. It was shown that floods, even the short duration ones, increase the decomposition velocity and the nutrient cycling relative to dry conditions. Thus, investigations that assess the nutrient budgets on the Upper Paraná River floodplain and the role of nutrients in its productivity should consider the detritus compartment and the effects of flood regimes upon its dynamics. Copyright © 2006 John Wiley & Sons, Ltd.     

香港岛南区雨水管网改造总体规划概述

香港岛南区雨水管网整体规划设计是临海、临江城市雨水管网规划设计的典型实例。重点介绍了该工程如何使用水力模拟软件辅助设计的基本方法以及其它相关内容:确定潮汐水位对雨水管网排水能力的影响,划分集水分区防洪级别,利用HydroWorks和MIKE11建立、校核、调整雨水管网的水文水力模型(以下简称模型)以保证模拟结果的可靠性,根据现状模型的运行结果对管网进行现状评价和洪水风险评估,利用规划模型辅助管网改造设计和方案最优化。     

Experimental study and modeling of pressure loss for foam-cuttings mixture flow in horizontal pipe

In this study,we first sought to elucidate foam rheology to describe foam flow behavior,and then to experimentally investigate the pressure losses for both foam and foam-cuttings flow in a horizontal pipe by considering both varied foam qualities of 80%, 85% and 90% and foam velocities.Also,a two-layer numerical model to predict pressure loss was developed based on experimental observations of cuttings behavior.Results show that the foam behaves like a power-law fluid.Furthermore,and the pressure loss signi...     

EFFECTS OF ARTIFICIAL FLOODING ON WATER QUALITY OF A FLOODPLAIN BACKWATER

Seasonal flooding of riverine backwaters is important in maintaining diverse aquatic habitats, but anthropogenic impacts have reduced the frequency and duration of such flooding. This study, conducted in a 2.5‐km‐long shallow floodplain severed meander backwater adjacent to the Coldwater River in Tunica County, Mississippi, USA, compared water quality during a late summer 30‐day artificial flooding period with 28‐day pre‐flood and 26‐day post‐flood periods. Flooding was simulated by pumping 0.22 to 0.35 m³ s^?1 from the river into the upstream portion of the backwater. In situ parameters (temperature, pH, dissolved oxygen, conductivity and fluorescent chlorophyll) were measured every 30 min at one site within the backwater. Solids (dissolved and suspended) and nutrients (phosphorus and nitrogen) were measured at three sites in the backwater and in the river every 3 to 5 days. Decreases in the amplitude of temperature, dissolved oxygen and pH diel cycles within the backwater were observed during flooding. Changes in patterns of solids and nutrients were also associated with flooding. Complex patterns in phosphorus and nitrogen emerged as a result of utilization by autotrophs (measured as chlorophyll) and seasonal changes. Artificial flooding in a shallow floodplain water body stabilized and improved water quality for aquatic biota and is a viable method for habitat rehabilitation in these systems. Copyright © 2011 John Wiley & Sons, Ltd.