热处理作用对含蜡原油流变性的影响

热处理技术是改善含蜡原油低温流动性的一种主要方法,以BH油田含蜡原油为例,通过一系列热处理试验对含蜡原油进行了流变性能研究,对实验数据进行了理论分析,并结合现场应用情况验证了试验结论的正确性。分析结果表明：温度是影响热处理效果的主要因素,中温段（50～60℃）的热处理会对含蜡原油的凝点产生恶化效果;高温段（70～95℃）的热处理可以大幅降低含蜡原油的凝点。冷却速度对含蜡原油热处理效果的影响至关重要,当冷却速度较小（0．5～1．0℃／min）时,油样热处理效果较好;冷却速度太快（1．2～1．5％／min）,将使热处理效果变差。剪切速率对热处理效果有一定影响,通常在较低速率的剪切作用下,原油热处理效果较好,随着剪切速率的增加,原油热处理效果变差。热处理后油样的稳定性对热处理效果的影响也不可忽视。     

入井液对含蜡原油析蜡点的影响

选取胜利油田某区块的含蜡原油,对其组成进行了测定和分析,考察了原油中的矿化度、固体颗粒含量以及pH值等条件对原油析蜡点的影响.研究表明:矿化度的提高和固体颗粒的加入分别使得原油析蜡点升高了3.2℃和4.2℃;酸性条件使得原油的析蜡点升高了0.5℃;碱性条件使得原油的析蜡点下降了1.1℃.     

高压含气条件下含蜡原油析蜡点测量方法

针对常规方法只能测量地面脱气油的析蜡点,不能测量高压含气条件(油藏条件)下含蜡原油析蜡点的不足,提出了以Arrhenius方程为理论基础,利用高压毛细管黏度计测量高压含气条件下含蜡原油析蜡点的方法。实验结果表明,实验油样地面脱气后析蜡点为63.74℃,油藏条件下析蜡点为59.73℃,含蜡原油地面脱气后更容易析蜡。建议采用油藏条件下的析蜡点作为注水设计参数。     

枣园油田原油的流变性及渗流特征研究

通过室内实验和矿场实践，认为枣园油田开发指标很差的原因是原油为非牛顿流体，属粘性流体。本文这了其不同于牛顿流体的流变性质和渗流特征。     

含蜡原油粘弹性与微观结构间关系的研究现状与分析

含蜡原油粘弹性源于其内部的蜡结晶量与复杂的蜡晶形态及结构,但二者间的定量关系仍未建立起来.在概述含蜡原油蜡晶形态和结构的定量表征与总结粘弹性研究的基础上,进一步分析了二者间定量关系的研究现状,并指出了存在的问题与进一步的研究课题.建议在悬浮液及凝胶体系的有关理论框架下,结合大量的试验研究,利用数理统计分析方法,深入探索粘弹性与蜡晶形态及结构间的定量关系,以丰富对原油流变学微观机理的认识.     

微观液滴分布对含蜡原油乳状液流变性的影响

通过显微镜观察并拍摄原油乳状液的微观结构图像,研究了乳状液体系分散相液滴大小及分布规律,以及微观液滴分布对乳状液体系流变性的影响机理。W/O型原油乳状液中含水率增加,引起内相液滴个数增多,小液滴所占的比例减小,相对大的液滴所占的比例增大;搅拌转速的增大,使体系内相液滴个数增多,平均液滴直径减小。通过测试在固定搅拌条件下制备的不同含水率的3种含蜡原油乳状液在原油凝点附近温度屈服特性和触变性等流变特性,可以发现随含水率的增大,乳状液体系屈服应力增大、触变性增强,且含水率越高,变化的趋势越明显。通过测试不同搅拌转速下制备的含水率为30% 的原油乳状液在原油凝点附近温度的触变性,可以看出随搅拌转速的增大,体系经受同等剪切速率剪切时对应的剪切应力增大、触变性增强。进一步建立了屈服应力与测试温度、含水率之间的关系式,其平均相对误差为9.83%。     

Non-isothermal crystallization kinetics of waxy crude oil

The crystallization behavior of Shengli waxy crude oil from the sol state to gel state was studied by the microscopic observation and DSC curve. The study shows that as the cooling rate decreases, the number of wax grains becomes smaller, the area is larger and the morphology of wax crystals is more irregular. Moreover, under different cooling rates, wax crystals were homogeneous transient nucleation, but the growth mode of wax crystals was different. When the cooling rate is between 1–4?°C/min, Crystallization Peak 1 wax crystal grows according to the mixed crystal mode of one-dimensional rod crystal and two-dimensional discoid crystal; When the cooling rate is between 6–8?°C/min, Crystallization Peak 1 wax crystal grows according to the mixed crystal mode of two dimensional discoid crystal and three-dimensional spherical crystal; Crystallization Peak 2 wax crystal grows according to the mixed crystal mode of two dimensional discoid crystal and three-dimensional spherical crystal at different cooling rates. Crystallization activation energy of crystallization Peak 1 and Peak 2 are 556.91?kJ/mol and 299.62?kJ/mol, respectively.     

Synthesis of new flow improvers from canola oil and application to waxy crude oil

Several techniques are employed to mitigate the problems associated with the crystallization of paraffin during the production and/or transportation of waxy crude oil. One of these techniques is the addition of chemicals that depress the pour point of the oil and inhibit the formation of paraffin crystals. In this work, the chemicals, polyamine amide (PAA), are prepared by aminolysis and polycondensation from canola oil and polyamine as substrates. Nitrogen atoms are fixed in the main chain of the polymers to modify the polarity. The effectiveness of the PAAs on four crude oil was tested as pour point depressants as well as paraffin inhibiters. The highest pour point reduction depression was achieved as 12.6°C. Differential scanning calorimetry and paraffin crystal morphology studies were conducted on simulated crude oil to elucidate the mechanism of pour point reduction.     

六参数含蜡原油触变模型

含蜡原油在较低温度下具有典型的触变特征,触变模型是含蜡原油输送管道再启动数值模拟的基础。在分析现有触变模型的基础上,结合含蜡原油的特性以及悬浮体系流变学的相关理论,提出了一个适用于含蜡原油的包含6个参数的黏塑性触变模型,并利用基于剪切率阶跃方法测试的触变数据对该模型进行了检验。结果表明,该模型对触变数据的拟合效果优于目前常用的包含8个参数的Houska模型,与12个参数的双结构参数模型相当。与Houska模型和双结构参数模型相比,所提出的六参数模型因拟合参数少且状态方程形式较为简单,通过优化算法拟合确定的触变参数定性上更为合理,更适用于含蜡原油管道停输再启动数值模拟。     

The use of bio-diesel based additive as rheology improver and pour point depressant of Nigerian waxy crude

The chemical method has proved to be the most effective mitigating method of wax deposition in petroleum system as it deals with the root cause of wax formation. Most of the commercial chemicals in the industry are very expensive and toxic. This paper aims the use of biodiesel based additives for improving the rheological behavior and pour points of waxy crude from Nigeria field. The biodiesels derived additives gave better performance than the commercial chemical and the seed oils as greatly improvement in rheology and pour point values of the waxy crude were observed     

Synthesis of cyclohexanone-alcohol hemiketals and evaluation as flow improver for waxy crude oil

In this paper, four novel cyclohexanone-alcohol hemiketals (KL-1, KL-2, KL-3, KL-4) as waxy crude oil flow improver have been prepared by cyclohexanone and 1-pentanol, 1-Hexanol, 1-heptanol, 1-octanol. Evaluation results demonstrate the hemiketal compounds have obvious effect on the viscosity and pour point of Henan crude oil. DSC analysis showed that waxing point and waxing peak decreased to a certain degree in 0.05% hemiketal solutions. Wax crystal morphology analysis indicated the four hemiketals played a role of nucleation in the process of waxy crude oil decoagulation, and in that way acts as waxy crude oil flow improver.     

An empirical correlation for estimating the viscosity of non-Newtonian waxy crude oils

Non-Newtonian fluids are the most complex ones when it comes to predicting their flow behavior. In the pre-existing models, rheological behavior in waxy crude oils is mainly affected by shear rate and thermal history of crude oils. In the present work, rheological characteristics of four different crude oils were studied by coaxial cylindrical rheometer at three different temperatures (40°C, 50°C, and 60°C) and a model was proposed keeping into consideration wax content for the first time. This model is prepared to predict the viscosity of four different crude oils with different wax content and at different temperature. The proposed model can efficiently estimate the viscosity as compared to other established models.     

特稠油,超稠油油藏热采开发模式综述

方法利用水平井热采模式．对特、超稠油油藏进行开采。目的改善开发效果，提高经济效益。结果对油层厚度小于5m的特、超稠油油藏不宜采用水平井热采；对油层厚度在5～10m的特稠油油藏或油层厚度大于10m的超稠油油藏，可采用水平井蒸汽吞吐和蒸汽驱开采；对原油粘度大于5×104mPa·s的超稠油油藏，适用蒸汽吞吐开采；对油层厚度大于20m，原油粘度大于20×104mPa·s的超稠油油藏，必须采用蒸汽辅助重力泄油技术。结论对已投入蒸汽吞吐的特稠油油藏，尤其是处于中后期吞吐阶段的区块，应采用蒸汽加氮气泡沫驱及现有在井与水平共组合蒸汽驱模式；对尚未开发的特、超稠油油藏，应采用水平井注蒸汽热采模式及其它新技术。