SiC单晶生长研究进展

SiC单晶生长是一个引人注目的研究热点，受到各国政府、科研人员的广泛关注。本文综述了SiC单晶生长的研究进展，对目前广泛采用的PVT法进行了详细介绍，讨论了原料、籽晶、温度、温度梯度、载体气压对单晶生长和质量的影响。对今后的研究方向提出了看法。     

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饱和压力是油藏的重要数据。它表示在地层条件下，原油中的溶解气开始分离出来的压力。饱和压力的大小，主要取决于油、气的组分和油藏的温度。目前主要通过ＰＶＴ取样分析测定和相关经验公式来确定它，前者和高，后者精度差，给饱和压力的确定带来困难。本文采用测压资料，根据井筒相态变化规律来计算油藏的饱和压力，并用实例验证，其结果与ＰＶＴ实测结果基本吻合。该方法具有快速、直观、经济效益显著等特点，值得推广应用。     

A crude oil data bank containing more than 5000 PVT and gas injection data

A set of more than 5000 data points is proposed here as a reference database for the evaluation of thermodynamic packages dedicated to the prediction of phase behavior and volumetric properties of oils. A set of 13 reservoir crude oils coming from different countries in the world was selected from PVT reports of the French petroleum company TOTALFINAELF. Measurements at reservoir conditions and at standard conditions were addressed. Constant mass expansion, differential vaporization, swelling test, slim tube test, multi-contact test and stock tank oil density measurement were the experiments considered as reference laboratory data source. In each case, the reservoir fluid was obtained from recombination of produced separator gases and stabilized oil. The stock tank oil was produced in the laboratory by using a multi-stage separation procedure.     

开发中后期试井解释中PVT及相关参数确定方法

为提高试井解释精度，针对胜利油区已开发油田的流体性质和开发现状对试井解释中的原油体枳系数、原油压缩系数、粘度等PVT参数进行了确定。根据各油田有代表性的高压物性资料，采用多项式的方法对实测点进行拟合，得出原油的高压物性与地层压力之间以及各参数间的相互关系式。同时给出了其他常用参数的确定方法。     

聚合物PVT参数采集系统的研究

介绍了聚合物PVT参数采集系统的组成,并对试验数据进行了初步分析。该系统包括测试模具、数据采集传输、数据存储显示等,分为硬件设计和软件设计两个部分。介绍了系统的硬件电路设计、固件程序设计、应用程序设计和上、下位机的通讯接口设计。     

南海西部海域复杂条件下PVT取样技术对策

南海西部海域新发现的含油气构造探井、评价井数量少,获取PVT样品成本高昂,且面临易脱气、易挥发、易凝析、组分缺失、样品污染、样品少和含水量高等诸多难题。在南海西部海域PVT取样统计分析的基础上,总结出了复杂条件下PVT取样的经验和适合海上油气藏PVT取样的技术对策。     

注空气过程中原油相行为及其影响分析

以中原油田明15块地层原油为例,基于室内空气原油PVT实验,建立了空气原油PVT模型,分析了空气注入对原油相行为的影响。并根据室内空气原油氧化实验结果,分析了空气与原油发生氧化反应后气体产物在原油中的溶解对原油相行为的影响。结果表明,在明15原始地层温度和压力下,地层原油能溶解其自身体积9.4%(v/v)的空气量,并且这些溶解了的空气对地层恢复能量的贡献为溶解气总体积的38.6%。氧化反应产物气体较之纯空气在原油中有更好的溶解度,但增溶幅度较小(增加1.4%)。氧化反应气体产物在原油中的溶解可使原油膨胀3.6%,膨胀能力有限。     

Predicting the Bubble-Point Pressure and Formation-Volume-Factor of Worldwide Crude Oil Systems

Abstract

This paper presents models for predicting the bubble-point pressure (P _b ) and oil formation-volume-factor at bubble-point (B _ob) for crude oil samples collected from several regions around the world. The regions include major producing oil fields in North and South America, North Sea, South East Asia, Middle East, and Africa. The model was developed using artificial neural networks with 5200 experimentally obtained PVT data sets. This represents the largest data set ever collected to be used in developing P _b and B _ob models. An additional 234 PVT data sets were used to investigate the effectiveness of the neural network models to predict outputs from inputs that were not used during the training process. The network model is able to predict the bubble-point pressure and the oil formation-volume-factor as a function of the solution gas–oil ratio, the gas relative density, the oil specific gravity, and the reservoir temperature. In order to obtain a generalized accurate model, back propagation with momentum for error minimization was used. The accuracy of the models developed in this study was compared in details with several published correlations. This study shows that if artificial neural networks are successfully trained, they can be excellent reliable predictive tools to estimate crude oil properties better than available correlations. The network models can be easily incorporated into any reservoir simulators and/or production optimization software.     

CMOS集成频率综合器的稳定性补偿

通过分析频率综合器的完整三阶闭环s域模型,同时采用根轨迹分析技术,定量分析了工艺、电压和温度引起的环路参数变化对频率综合器稳定性的影响,并提出变化裕量的概念来进行稳定性分析和参数设计.为了获得更加稳定的系统,在电荷泵中设计了结构简单的电流单元用于补偿额外的参数变化,并采用线性压控增益的VCO来减小参数的变化.最后设计了一个分辨率为250kHz,频率范围为1～1.05GHz的集成频率综合器来验证上述的分析和设计方法.     

超声检测在聚合物PVT关系测试中的应用

聚合物加工过程发生物态转变,测试对应的PVT数值变化对于精确控制工艺参数极其重要.概述PVT的检测方法,并研究超声波信号与聚丙烯PVT特性的相互关系.实验显示:在熔融状态超声波声速与聚丙烯比容(密度)存在线性对应关系.可通过超声波来间接测试聚合物熔体密度的变化,为精密加工提供控制的基础.