Experimental study on flow characteristics of tetrahydrofuran hydrate slurry in pipelines

Tetrahydrofuran（THF） was selected as the substitute to study the flow behaviors and the mechanism of the hydrates blockage in pipelines.The slurrylike hydrates and slushlike hydrates are observed with the formation of hydrates in pipeline.There is a critical hydrate volume concentration of 50.6% for THF slurries and pipeline will be free of hydrate blockage while the hydrate volume concentration is lower than the critical volume concentration;otherwise,pipeline will be easy to be blocked.Fully turbulent flow occurs and friction factors tend to be constant when the velocity reaches 1.5 m/s.And then,constant values of friction factors that depend on the volume concentrations in the slurry were regressed to estimate the pressure drops of THF hydrate slurry at large mean velocity.Finally,a safe region,defined according to the critical hydrate volume concentration,was proposed for THF hydrate slurry,which may provide some insight for further studying the natural gas hydrate slurries and judge whether the pipeline can be run safely or not.

FLUID FLOW SEPARATION CHARACTER ON NOVEL HYBRID JOURNAL BEARING

The influence of the structure and running parameters of a novel spiral oil wedge hybrid journal bearing on the fluid flow trace is investigated. The governing equation of the flow trace of lubricant is set up, and the simulation is carried out by using finite difference method. The results show that the lubricant flow status and end leakage quantity are greatly influenced by spiral angle,and that the rotating speed has little influence on the flow status. With advisable geometry design, the separation of lubricant between different oil wedges can be obtained, which can decrease the temperature rise effectively.

Characterizing Internet Backbone Traffic Based on Deep Packets Inpection and Deep Flows Inspection

Based on the massive data collected with a passive network monitoring equipment placed in China's backbone,we present a deep insight into the network backbone traffic and evaluate various ways for improving traffic classifying efficiency in this paper.In particular,the study has scrutinized the network traffic in terms of protocol types and signatures,flow length,and port distribution,from which meaningful and interesting insights on the current Internet of China from the perspective of both the packet and flow levels are derived.We show that the classification efficiency can be greatly improved by using the information of preferred ports of the network applications.Quantitatively,we find two traffic duration thresholds,with which 40% of TCP flows and 70% of UDP flows can be excluded from classification processing while the impact on classification accuracy is trivial,i.e.,the classification accuracy can still reach a high level by saving 85% of the resources.

Selective Area Growth and Characterization of GaN Nanorods Fabricated by Adjusting the Hydrogen Flow Rate and Growth Temperature with Metal Organic Chemical Vapor Deposition

CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.

Characterization and Modelling of High Temperature Flow Behaviour of V Modified 2.25Cr-1Mo Heat Resistant Steel Plate

In order to study the high temperature flow behaviour of the V modified 2.25Cr-1Mo steel plate to guide the industrial rolling practice, the hot compression tests were carried out at the temperatures from 900 ℃ to 1150 ℃ and the strain rates from 0.01s^-1 to 1 s^-1 on Thermecmastor-Z equipment. Based on the experimental data of the hot compression tests, a kind of Arrhenius-type constitutive equation was developed.The equation can accurately show the relationship between the flow stress and the deformation temperature, the strain and the strain rate. The measured true stress-true strain curves exhibit two kinds of flow stress curves. Moreover, the forming mechanisms of these two types curves were explained by softening, wok hardening theory as well as metallographic and hardness experimental results. The accuracy of the developed Arrheniustype constitutive equation was identified by three kinds of statistic parameters and also by comparison of the measured and predicted data. The reasonable value of the three types of statistic parameters and the good agreement between the experimental and predicted data can confirm the validity of the developed Arrheniustype constitutive equation for V modified 2.25 Cr-1 Mo heat resistant steel plate.

Petrophysical Analysis and Flow Units Characterization for Abu Madi Pay Zones in the Nile Delta Reservoirs

Field development typically requires detailed petrophysical analysis and well defined hydraulic flow units for comprehensive formation evaluation and reservoir characterization. In the present study, pay zones petrophysics are studied using an assembly of well log data from 8 wells together with core plugs measurements. Petrophysical analysis showed a good reservoir quality with average water saturation increasing toward the East and Southeast of the study area. Using a multi-linear regression technique on well logs and core data, permeability is estimated at well locations for flow unit characterization and flow capacity calculation. Results showed that five hydraulic flow units are identified through the studied wells, with relatively good correlation. Such correlation indicated a good continuity in the net pay zone of Abu Madi Formation in the Nile Delta reservoirs. The developed hydraulic flow units (HFUs) are classified according to its hydraulic conductivity into two main categories: the first category comprises the units with low permeability (K 1270 mD). The reservoir flow capacity (RFC) of these units indicated the development of 4 distinct classes (~11, ~30, ~80, and greater than 130 D.ft). The wells within the Northwestern part of the study area showed three HFUs that relatively vary from those located at the Southeast where two HFUs are only developed. In addition, the Southeastern part of the reservoir is characterized by good RFC as indicated by the development of high order HFUs (3, 4, and 5) compared to the Northeastern part with predominated low order HFUs (1, 2, and 3). Such results are crucial for the efficient field development and profound reservoir management of oil and gas fields in the Nile Delta.

Numerical Simulation of Oil and Gas Two-Phase Flow in Deep Condensate Gas Reservoirs in Bohai Buried Hills

The BZ19-6 gas field is characterized by high temperature and high pressure (HTHP), high condensate content, little difference between the formation pressure and dew point pressure, and large amount of reverse condensate liquid. During the early stage of depletion development, the production gas-oil ratio (GOR) and production capacity remain relatively stable, which is inconsistent with the conventional reverse condensate seepage law. In view of the static and dynamic conflict in development and production, indoor high-temperature and high-pressure PVT experiment was carried out to reveal the mist-like condensation phenomenon of fluids in the BZ19-6 formation. And the seepage characteristics of condensate gas reservoirs with various degrees of depletion under the condition of HTHP were analyzed based on production performance. The change rule of fluid phase state was analyzed in response to the characterization difficulties of the seepage mechanism. The fluid state was described using the miscible mechanism. And the interphase permeability interpolation coefficient was introduced based on interfacial tension. By doing so, the accurate characterization of the “single-phase flow of condensate gas-near-miscible mist-like quasi single-phase flow-oil-gas two-phase flow” during the development process was achieved. Then the accurate fitting of key indicators for oilfield development was completed, and the distribution law of formation pressure and the law of condensate oil precipitation under different reservoir conditions are obtained. Based on research results, the regulation strategy of variable flow rate production was developed. Currently, the work system has been optimized for 11 wells, achieving a “zero increase” in the GOS of the gas field and an annual oil increase of 22,000 cubic meters.

海水二次循环冷却设备腐蚀故障在线诊断研究

为了在短时间内完成对二次循环设备腐蚀故障的精准诊断,提出海水二次循环冷却设备腐蚀故障在线诊断方法。根据冷却设备循环机组的工作参数,构建腐蚀故障出现前的设备正常运行状态函数。结合腐蚀故障产生因素及环境条件设置约束条件,确定冷却设备腐蚀故障位置影响因子。计算每个故障位置的判定系数,以在线确定故障位置。横向对比冷却设备管道中不同位置节点力学数据,并校验分析故障位置判定系数,以获取冷却设备腐蚀故障位置判定系数指标量。创新性地最大化短期记忆网络的池化层,并依据故障位置判定系数及指标量,求解腐蚀故障实际触发值和整定值,以实现设备腐蚀故障的在线诊断。测试结果表明,所提方法的诊断准确率均在97%以上。该方法具有见效快、用时短、诊断准、效果稳的特点,能够应对当前大部分海水二次循环冷却设备腐蚀故障的在线诊断任务。

一种基于混合流量表征的通用自动化流量分类方法

提出一种自动化流量分类方法,用于解决机器学习在网络流量分析任务时的问题。该方法通过语义和二进制的混合流量表征方法生成统一的网络流量数据包表示,应用于特征表示和模型训练。同时,将这种网络流量表征方法与自动化机器学习相结合,提出具有兼容性的通用自动化机器学习流量表征和分类方法。此方法可以在很大程度上消除各种流量分析任务中的特征提取和模型调整步骤,有助于将机器学习技术更加广泛地应用于流量分析任务中。在ISCX2016-VPN和Kitsune数据集上对提出的方法进行评估,实验表明,该方法在这些数据集上表现良好。

单孔排气气泡特征识别与参数提取方法

气液两相流广泛应用于多种工业领域当中,测量气泡特征参数并进行统计分析可以探究气泡的运动及生长规律,这对相关物理规律和过程控制研究具有重要意义。然而气泡在运动中会发生融合、破碎等现象,导致图像中气泡的重叠粘连,以及拍摄背景的不均匀性均会对气泡特征数据提取造成较大误差。本文采用高速摄像技术获得了不同液体流速与通气量下的气泡图像,通过对距离变换图像的极值点进行抑制与融合,改进了分水岭算法的前景标记提取方法,实现了气泡的准确分割,进而对分割气泡进行最小二乘椭圆拟合重构,获取了气泡参数。对比分析发现,相较于腐蚀运算和阈值分割提取标记的方法,本文方法准确率分别提高了22.7%与13.6%。通过对气泡特征进行统计分析,发现随着通气量的增加,气泡数量略微增多而平均尺寸显著增大,表明通气量对气泡尺寸有着重要影响。通气量相同,随着来流速度的增加,气泡破碎,气泡的数量增加且平均尺寸减小。

隔离层下单漏斗放矿力链演变的参数敏感性分析

利用PFC软件,以同步充填留矿法为背景,选取隔离层厚度A、隔离层界面摩擦因数B、矿石颗粒摩擦因数C及颗粒半径D作为正交试验的四种影响因素,对力链特征参数的一般变化规律进行分析,研究影响力链演变的参数及其敏感性。结果表明:力链数量先减少后增加;力链长度的概率分布曲面呈指数形式递减,短力链所占比例逐渐减少,长力链所占比例逐渐增加;力链强度表现出先减少后增加的规律;力链强度的概率分布先呈指数式上升,后呈指数式递减;四种因素对正交试验指标影响的主次顺序为CDAB;对应的最优方案为颗粒摩擦因数0.8、颗粒半径0.008 m、隔离层厚度0.004 m、隔离层界面摩擦因数0.5,此时散体介质体系在放矿过程中最为稳定。

高能量密度液流电池关键材料与先进表征

氧化还原液流电池具有安全性能高、可深度充放电、设计灵活等优势,在大规模储能领域得到了广泛关注,是实现“双碳”目标的一种重要储能技术。然而,较低的能量密度限制了液流电池的应用前景,因此亟需开发高能量密度的液流电池体系。液流电池的能量密度取决于电池关键材料的性能,尤其是正、负极电解液中活性物质的溶解性和电解液的电化学活性。因此,液流电池关键材料的开发和性能表征是液流电池领域中的重要研究方向。本文综述了高能量密度液流电池的主要构建策略,着重讨论了多电子转移体系、提高活性物质溶解度、半固态流体电池和氧化还原靶向反应液流电池四种提升电池能量密度的方法,并介绍了当前液流电池领域中的先进原位表征技术,包括原位拉曼光谱、原位紫外-可见吸收光谱、原位红外光谱和原位核磁共振技术。本文总结了高能量密度液流电池关键材料的研究进展,明确了原位表征技术在揭示复杂电化学反应机理中的重要作用,并对高能量密度液流电池的应用场景进行了展望。

从时空嬗演看日用类书的书写表征与知识传播——16至19世纪中国日用类书发展的几点思考

本文以16至19世纪中国日用类书发展变迁为考察对象,探讨中西方日用类书的书写表征与知识传播。通过对中国历史上日用类书的书写范围及叙事传统探析;以及不同历史阶段类书呈现的民众日用生活意义的本真性书写、商业贸易与情感的双重价值旨归;中国日用类书的本位主述与文化知识流向、西方日用类书中的科学知识、经验与信息传播。从具体而微观的视角审视和考量日用类书的知识流向及主述模式,在尽量还原当时中西方社会交流状态之余,思索中西日用类书“观之-参与”交互模式中渐成的传播共享。

气态流动鼓泡发生器的研制与应用

随着全球化石资源的不断消耗,可再生资源的转化利用已成为科研工作者的关注焦点。由生物质经过生物或化学方法转化而获得的生物基低碳醇的催化转化是近些年来研究的热点。为高效率探索多种模型催化反应,该文研制了气态流动鼓泡发生器来替代传统的固定床反应器的进料过程,目的是进行不同的模型催化反应探索实验。通过对比二者的实验结果显示,该设备具有误差小、试验快、操作简单等特点,且其设计所占空间小、便携等优点,适用于多种原位表征技术。通过将气态流动鼓泡发生器与原位漫反射红外光谱联用,使学生深入学习了红外理论知识和仪器设备的工作原理,将学生们学到的催化学科的相关基础知识进行融会贯通。气态流动鼓泡发生器不仅辅助科研实验的探索,还可拓展到实验教学的应用,提升学生的科研创新能力,为科教融合、教研一体提供了新范式。

Reservoir stress path and induced seismic anisotropy： results from linking coupled fluid-flow/geomechanical simulation with seismic modelling

We present a workflow linking coupled fluid-flow and geomechanical simulation with seismic modelling to predict seismic anisotropy induced by non-hydrostatic stress changes. We generate seismic models from coupled simulations to examine the relationship between reservoir geometry, stress path and seismic anisotropy. The results indicate that geometry influences the evolution of stress,which leads to stress-induced seismic anisotropy. Although stress anisotropy is high for the small reservoir, the effect of stress arching and the ability of the side-burden to support the excess load limit the overall change in effective stress and hence seismic anisotropy. For the extensive reservoir, stress anisotropy and induced seismic anisotropy are high. The extensive and elongate reservoirs experience significant compaction, where the inefficiency of the developed stress arching in the side-burden cannot support the excess load.The elongate reservoir displays significant stress asymmetry,with seismic anisotropy developing predominantly along the long-edge of the reservoir. We show that the link betweenstress path parameters and seismic anisotropy is complex,where the anisotropic symmetry is controlled not only by model geometry but also the nonlinear rock physics model used. Nevertheless, a workflow has been developed to model seismic anisotropy induced by non-hydrostatic stress changes, allowing field observations of anisotropy to be linked with geomechanical models.

Factor Controlling Reservoir Properties and Flow Unit Determination in the Ilam Formation of Dezfol Embayment at Zagros Fold-Thrust Belt, Southwest of Iran

Dezfol embayment in the Southwest of Iran is located in the Zagros fold-thrust belt, which is one of the world’s largest petroleum provinces. Ilam Formation (Santonian-Companian) is one of the reservoir formations in this area that has been less studied. This paper focused on reservoir properties in this formation using petrography and petrophysics data. According to the petrography studies Ilam Formation composed of limestone as dominant lithology. Detailed petrographic analyses, have led to identification of 10 micro-facies which are represented as a carbonate ramp depositional model. Also petrographic analyses are revealed that cementation, dissolution, compaction and dolomitization are most important digenetic processes. Detailed petrographic analyses and petrophysics data showed that due to mud-supported nature of more facies (inherited low reservoir potential from their depositional settings), diagenetic process plays an important role in increasing of reservoir quality. However cementation and dissolution had negative and positive effects on Ilam reservoir formation, respectively. Finally at the end for better correlation and to create a flow unit, according to the petrography data and using petrophysics log, this reservoir is divided into 5 units (flow unite) by using Geolog software and then they have been correlated across the field.

基于地震属性智能融合的湖相重力流沉积致密砂岩储层预测

湖相重力流是目前沉积学研究的热点与难点,也是致密油、页岩油富集的有利场所,鄂尔多斯盆地庆城油田三叠系延长组作为致密油、页岩油的典型代表已显示出巨大的勘探开发前景。然而,由于湖相重力流砂体分布认识不清,导致油田并未达到预期的开发效率。本文采用支持向量机(SVR)的机器学习方法,先优选频段再优选属性,建立分频属性与测井解释砂体厚度的非线性映射关系,实现了致密砂岩的定量预测。研究结果表明,低频地震属性适合预测厚层砂体,高频地震属性适合预测薄层砂体;采用机器学习的方法,将不同频率的地震属性智能融合,能够兼顾预测不同厚度砂体,既提高了地震属性的解释精度,又降低了地震解释的多解性,实现了砂体厚度的定量预测。检验结果显示,智能融合属性与砂体厚度的分布趋势与值域区间基本一致,智能融合属性预测砂体分布的可靠性明显提高,与测井解释砂体厚度的相关性由0.60提高至0.79,大多数井点处预测的砂体厚度误差小于5 m。继而,根据融合属性与测井解释,刻画了研究区的沉积微相展布特征:研究区目的层发育湖底扇沉积,细分为分支水道、朵叶主体、朵叶侧缘、滑塌体与朵叶间/水道间5种沉积微相;砂体主体呈扇形连片式沉积,厚度顺物源方向逐渐减薄;分支水道呈窄条带状树形分叉,下切发育于朵叶体之上;朵叶体沉积为研究区的沉积主体;滑塌体为湖底扇前端失稳滑塌形成的小规模孤立砂体,长轴方向多平行于湖底扇前端。研究成果对油田下一步高效开发具有重要意义。

单抗制剂中典型不溶性微粒的形态特征分析

目的:分析单克隆抗体(简称单抗)中典型不溶性微粒图片特征,建立典型不溶性微粒的图谱特征数据库和相应的预警机制。方法:通过采用微流成像技术检测反复冻融、含气泡或硅油、酶解、氧化等不同条件下的单抗中存在的不溶性微粒,筛选关键特征参数用于区别典型不溶性微粒。结果:不同类型不溶性微粒长宽比、密实度、强度、粗糙度和透明度等参数有明显区别,以此可区分不同类型不溶性微粒。此外,获得了不同种类微粒的关键形态特征,初步建立了图谱特征数据库。结论:利用微流成像技术建立对典型不溶性微粒进行比较和分类的方法,可以建立相应预警机制,对单抗中不溶性微粒进行溯源分析和风险评估。