聚合物驱油螺旋型静态混合器流场仿真与实验研究

发布时间：2018-01-04 22:33

本文关键词：聚合物驱油螺旋型静态混合器流场仿真与实验研究　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,三次采油(EOR)技术已广泛应用于国内各主力油田。聚合物注入(简称“注聚”)驱油方法因其较高的原油采收率已成为三次采油技术中的主要采油方式。注聚采油技术利用静态混合器(以下简称“静混”)将聚丙烯酰胺(PAM)母液与水混合后注入井底进行驱油。其驱油效率主要取决于混合后的溶液粘度,粘度越高,驱油效率越高。常规的静态混合器由于对聚合物剪切作用较强,造成粘度损失率较高,导致驱油效率下降,进而影响到石油开采产量。本文通过对静混混合机理及PAM溶液粘度理论的分析,明确了影响溶液粘度变化的因素,主要包括静混结构参数(单元螺距、单元间距)及结构形式(单元旋向组合)、流体初始流速三方面。在此基础上通过计算流体力学仿真,对以上三方面进行优化设计,得到两种改进后的低剪切静混,通过实验证明优化有效,粘损得到控制。本文具体内容如下:首先分析了静混的混合机理,获得了静混中流体的压强分布及流速分布。之后阐述了常用的聚合物溶液粘度计算模型,结合PAM溶液自身特性建立起以Carreau方程为基础的PAM溶液粘度计算模型,并明确了从静混结构形式、结构参数及初始流速三方面入手进行粘损控制优化设计。之后通过计算流体力学仿真的手段,利用先进的CFX软件对常规静混和实验室研发的新型螺旋型静混进行性能对比,仿真结果表明后者性能更优。在此基础上展开螺旋型静混的优化设计。分别研究了静混结构参数及流体初始流速对其混合均匀度及出入口压差的影响,并得出作用关系。根据仿真结果对静混结构参数进行了初步优化。利用PAM溶液粘度计算模型,分别对静混结构参数及流体初始流速对于出口处流体粘度的影响进行了仿真分析,得出作用关系并根据仿真结果进一步优化了静混结构参数。在两次优化结果的基础上,对结构形式进行改进,设计了两种不同形式的静混单元,并对二者混合效果进行仿真,结果表明流体通过两种静混器后均混合均匀,且后者出口处混合液粘度高于前者,证明第二种结构形式更优。最后搭建实验装置,对优化后静混的粘损控制效果进行验证。实验结果表明,在保证混合均匀的前提下,优化设计的两种静混的粘损值均低于常规静混,且二者的粘损情况与仿真结果较为吻合,在一定程度上验证了理论与仿真分析的正确性。
[Abstract]:Right now. Tertiary oil recovery (EOR) technology has been widely used in major oilfields in China. Polymer injection (abbreviated as "polymer injection"). Because of its high oil recovery efficiency, flooding method has become the main way of oil recovery in tertiary oil recovery technology. The static Mixer ("static Mixer") is used to produce polyacrylamide (PAM). The oil displacement efficiency is mainly determined by the viscosity of the solution after the mixture of mother liquor and water is injected into the bottom hole for oil displacement. The higher the viscosity, the higher the oil displacement efficiency. The higher the viscosity loss rate is, the higher the oil displacement efficiency is due to the strong shear effect of the conventional static mixer. Through the analysis of static mixing mechanism and viscosity theory of PAM solution, the influence factors of solution viscosity change are clarified, including static mixing structure parameters (unit pitch). Element spacing) and structure form (element rotation combination, fluid initial velocity three aspects. On this basis, through computational fluid dynamics simulation, the above three aspects of optimization design. Two kinds of improved low-shear static mixing are obtained, and the experiment results show that the optimization is effective and the viscosity loss is controlled. The main contents of this paper are as follows: firstly, the mixing mechanism of static mixing is analyzed. The pressure distribution and velocity distribution of the fluid in static mixing are obtained, and then the commonly used viscosity calculation model of polymer solution is described. Based on the Carreau equation, the viscosity calculation model of PAM solution was established, and the structure of PAM solution was defined according to the characteristics of PAM solution. The optimal design of viscous loss control is carried out from three aspects of structure parameters and initial velocity, and then the method of computational fluid dynamics simulation is used. The advanced CFX software is used to compare the performance of the new spiral static mixing developed by the conventional static mixing laboratory. The simulation results show that the performance of the latter is better. On this basis, the optimal design of spiral static mixing is carried out. The effects of static mixing structure parameters and initial fluid velocity on the mixing uniformity and inlet pressure difference are studied respectively. According to the simulation results, the static mixing structure parameters were preliminarily optimized, and the viscosity calculation model of PAM solution was used. The effects of static mixing structure parameters and initial flow velocity on the viscosity of the fluid at the outlet are simulated and analyzed respectively. According to the simulation results, the static mixing structure parameters are further optimized. On the basis of the two optimization results, the structure form is improved, and two different static mixing elements are designed. The simulation results show that the fluid mixture is uniform after passing through the two static mixers, and the viscosity of the mixture at the exit of the latter is higher than that of the former, which proves that the second structure is better. Finally, the experimental device is built. The experimental results show that the viscosity loss of the two kinds of static mixing is lower than that of the conventional static mixing under the premise of uniform mixing. The viscosity loss of the two is in good agreement with the simulation results, which verifies to some extent the correctness of the theory and the simulation analysis.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE934

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