定向井层流注水泥环空界面数值模拟

发布时间：2018-05-25 00:13

本文选题：层流 + 定向井　；参考：《西南石油大学》2015年硕士论文

【摘要】：在固井过程中,提高环空注水泥顶替效率是防止钻井液窜槽、保证水泥胶结质量和提高水泥环密封效果的基本前提。由于顶替效率的影响因素复杂多变,涉及到工艺措施、地层条件、井身结构、流体流动性能及固井工具等多个环节,难以利用室内实验手段进行精确物理模拟,因而利用数值模拟手段系统研究环空顶替机理具有重要的现实意义。本文针对定向井(包括水平井),基于大型CFD软件FLUENT,建立了177.8-×215.9mm的环空顶替模型,利用数值模拟的手段分别从四个方面模拟研究了影响环空顶替效率的因素。在偏心度对倾斜环空顶替的影响情况方面,本文在工程运用的常见偏心范围内取值,固定某些因素不变,模拟得出不同偏心度下纵剖面顶替情况和顶替效率变化情况。然后变化偏心度和密度差或者偏心度和井斜角,组合分析多个影响因素的共同影响情况。按照同样的方法,分析了井斜角、密度差、顶替速度三个因素影响下的纵剖面变化情况和顶替效率变化情况。最后模拟结果表明：对于幂律模式,在一定井斜时,增加顶替液与被顶替液的密度差、增加顶替速度、选定适当的偏心度,都有利于提高顶替效率；反之,若密度差、偏心度和顶替速度等因素匹配不适,会使水泥浆的顶替效率降低。研究结果有助于明确定向井(包括水平井)中注水泥过程的环空顶替机理,为其注水泥设计与施工提供一定的理论依据。
[Abstract]:In the cementing process, it is a basic prerequisite to improve the displacement efficiency of annular injection cement to prevent the channeling of drilling fluid, to ensure the cement cementation quality and to improve the sealing effect of cement ring. Because the influence factors of displacement efficiency are complex and changeable, it is difficult to use laboratory experiments to carry out accurate physical simulation because it involves many links, such as technological measures, formation conditions, wellbore structure, fluid flow performance and cementing tools, etc. Therefore, it is of great practical significance to systematically study the mechanism of annular displacement by means of numerical simulation. In this paper, a annular displacement model of 177.8-脳 215.9mm is established for directional wells (including horizontal wells) based on large scale CFD software fluent. The factors affecting the efficiency of annular displacement are simulated from four aspects by means of numerical simulation. In terms of the influence of eccentricity on the displacement of inclined annular space, in this paper, the displacement of longitudinal profile and displacement efficiency under different eccentricity are simulated by taking values within the common eccentricity range used in engineering and fixing some factors unchanged. Then the eccentricity and the density difference or the eccentricity and the angle of the well are changed, and the combined influence of many factors is analyzed. According to the same method, the variation of longitudinal profile and displacement efficiency are analyzed under the influence of three factors, such as inclined angle, poor density and displacement velocity. The simulation results show that, for the power law model, increasing the density difference between the displacement fluid and the displaced fluid, increasing the displacement velocity and selecting a proper eccentricity are beneficial to the improvement of the displacement efficiency, whereas, if the density is different, The mismatch of eccentricity and displacement velocity will reduce the displacement efficiency of cement slurry. The results are helpful to clarify the annular displacement mechanism of cementing process in directional wells (including horizontal wells) and to provide some theoretical basis for the design and construction of cement injection.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE256

【参考文献】