Viscosity Behavior of Foamy Oil: Experimental Study and Modeling

Abstract

Heavy oil cold production is faced with the foamy oil phenomenon: while extracted, a heavy crude oil is submitted to a depletion that can induce the formation of dispersed gas bubbles and makes it appear as a foam. This situation results in a change of the flow properties of the live oil that is still debated: correlations predict a decrease or an increase in the gas bubble-dispersed oil viscosity with the gas volume fraction. We attempted to improve the understanding of the foamy oil behavior through rheological measurements. A live oil was depleted inside the pressure cell of a controlled stress rheometer. The occurrence of bubbles was checked and visualized with x-ray scanning experiments. Viscosity was continuously measured using oscillatory and continuous tests. This particular experimental approach allowed us to successfully study the rheological behavior of a foamy oil in relationship with the two main parameters, which are the composition and the viscosity of the crude oils. A theoretical model describing the viscosity of a foamy oil has been established. It takes into account both first-order kinetics of appearance and release of bubbles in oil and a basic suspension model. Results from this model are in agreement with experimental data obtained from different heavy crude oils.     

High-temperature electron mobilities in LPE-Grown GaP

We report measurements to 500°C of resistivity and Hall mobility in Sn-doped, n-type GaP grown by liquid phase epitaxy. Samples with room-temperature carrier densities between 1 × 10¹⁶ and 1 × 10¹⁸cm⁻³ were studied. Mobilities were in the range 100–180 cm²/V-sec at room temperature and in the range 27–35 cm²/V-sec at 400°C. Carrier densities increased by only about a factor of two with increasing temperature. Theoretical fits to the mobility data were made by considering contributions from intervalley, polar-optic, acoustic-deformation-potential, and ionlzed-impurity scattering mechanisms. Our results confirm the utility of GaP for high-temperature device applications and provide important information on electrical parameters needed for device modeling and design.     

液体空分设备设计开发中的技术分析

简介了液体空分设备设计中几种工艺流程的特点和组织原则,并对流程设计中的一些技术问题进行了分析探讨。     

Director Field in a Bipolar Configured Nematic Droplet

Polymer dispersed liquid crystal(PDLC) have found its application in flexible displays and switchable windows. Such applications require dimension of the droplets to be several micro meters[1]. Recently, it is found that droplets in PDLC may gather together in some districts by special manufacture process, to form switchable period holographic gratings. Such an application requires dimension of the droplets less than 200 nm[2]. In spite of dimension of the droplets, whether in micrometers …     

Precursor system of liquid crystalline phase containing propolis microparticles for the treatment of periodontal disease: development and characterization

Precursor systems of liquid crystalline phase were prepared using the surfactant PPG-5-Ceteth-20, isopropyl myristate, and water; gelatin microparticles containing propolis were then added into these systems. Homogeneity of dispersion, the in-system microparticle morphology, and sedimentation behavior of each formulation were evaluated. The rheological and mechanical properties (hardness, compressibility, and adhesiveness), the work of syringing, and the propolis release profile were also evaluated. All the formulations exhibited pseudoplastic flow and thixotropy, and they displayed storage modulus, loss modulus, dynamic viscosity, and loss tangent that depended on temperature, frequency, and composition. Mechanical properties varied significantly among the formulations being affected by changes in the composition and temperature. Raising the concentration of surfactant and adding propolis microparticles significantly decreased the work of syringing. The drug release was non-Fickian (anomalous) and there was no significant difference between the tested systems in the times required for 10%, 30%, and 50% release of the initial drug loading.     

反应温度对液态聚硅烷高压合成聚碳硅烷性能的影响

以液态聚硅烷(LPS)为原料,在高压釜内反应制备了聚碳硅烷(PCS)先驱体。研究发现,随着反应温度的升高．PCS的分子量增大,产率提高,软化点提高．Si—H键含量降低．在反应过程中LPS首先转化为小分子量的PCS．然后是小分子的PCS间发生脱氢及少量脱甲烷缩合使分子量长大。450℃后,反应产率明显增加,分子量分布出现中分子量峰。     

研究液体表面特性的激光动态光散射系统

本文介绍了我们已建立的用微机控制的激光散射实验系统,并用已知常规液体及低介面张力的二相微乳体系样品测量,实验结果与预期相符。     

应用双头电导探针技术测量气液两相泡状流局部参数

本研究应用双头电导探针技术测量气泡局部参数,从而揭示了气液两相泡状流的内部流动规律。