水平井注水泥流动过程计算研究

发布时间：2018-06-20 03:52

本文选题：水平井注水泥 + 偏心环空　；参考：《西南石油大学》2017年硕士论文

【摘要】：传统注水泥设计的计算部分如泵压、循环压耗等,由人工计算足以胜任,但涉及到U型管效应等动态的复杂计算时,纯人工计算工作量巨大,结果误差大。选用合理准确的计算模型,使用计算机技术对注水泥的整个流动过程进行研究,不仅能得到更精确的计算结果,且能对整个注水泥过程进行预测与计算,为安全、高效、可控的注水泥施工作业提供了依据。在整个注水泥流动过程计算中,选择合理的注水泥顶替效率计算模型及U型管效应计算模型是其重要部分。水平井注水泥作业中,提高注水泥顶替效率是提高固井质量的前提。目前对于水平井顶替效率研究的主要手段有施工现场的数据统计及室内实验,水平井顶替效率的数学模型研究还不充分。为了定量研究水平井注水泥顶替效率的影响因素,为室内实验及现场固井施工提供指导性建议,提高固井质量,降低室内实验及固井施工成本,本文针对水平井,应用微元分析法对钻井液微元体进行受力分析,根据注水泥过程中钻井液被驱替达到稳定状态时的平衡条件,建立了水平井偏心环空中钻井液滞留层厚度计算模型,进而得到注水泥顶替效率模型,分别分析了偏心度、井斜角、钻井液屈服应力及水泥浆流变参数对水平井注水泥顶替效率的影响。计算结果表明,当套管偏心度增大时,环空窄间隙处顶替效率急剧下降,严重影响固井质量;钻井液静切力增大时,钻井液滞留层厚度增加,环空窄间隙处滞留层厚度增加明显,固井时应尽量保证套管居中,同时尽量降低钻井液静切力。注水泥作业时,要取得良好的固井质量,须严格控制各随注水泥施工时间而改变的参数及井底环境的稳定情况,传统注水泥设计中,对注水泥流动过程的计算进行了简化,只涉及理想状态下的环空流态判断、井下压力计算、泵压计算等,忽略了由井内流体密度差引起的U型管效应的影响。当前注水泥的U型管效应计算模型只适用于直井注水泥过程,缺乏对水平井注水泥的U型管效应研究,本文针对水平井注水泥的流动过程,用欧拉微分方程对水平井的注水泥流动过程进行了研究,得到了水平井U型管效应计算模型。针对水平井的注水泥流动过程计算结果表明,水平井注水泥时会发生U型管效应,影响环空注水泥流速,降低水泥浆对钻井液的紊流驱替时间,降低注水泥顶替效率。本文根据上述水平井顶替效率计算模型和水平井U型管效应计算模型,在Visual Studio 2013开发平台下,基于SQL Server 2008数据库和WPF框架,运用C#语言开发了水平井注水泥流动过程计算软件。该软件在常规注水泥设计的基础上,重点计算水平井注水泥顶替效率及整个注水泥的井内流动过程。软件运行稳定、各模型计算结果可靠,可计算及预测水平井注水泥井内流动过程,为现场施工及室内实验提供理论依据及参考。
[Abstract]:The calculation part of traditional cement injection design, such as pump pressure, circulating pressure consumption and so on, is competent enough by manual calculation, but when it involves the complex calculation of dynamic calculation such as U-shaped pipe effect, the workload of pure manual calculation is huge and the result error is large. Choosing a reasonable and accurate calculation model and using computer technology to study the whole flow process of cement injection can not only obtain more accurate calculation results, but also predict and calculate the whole cementing process, which is safe and efficient. The controllable cementing construction provides the basis. In the calculation of the whole cement-injection flow process, it is important to choose a reasonable model for calculating the displacement efficiency of cement injection and a model for calculating the U-shaped pipe effect. In horizontal well cementing operation, the premise of improving cementing quality is to improve the displacement efficiency of cement injection. At present, the main methods of horizontal well displacement efficiency research are data statistics and laboratory experiments, but the mathematical model of horizontal well displacement efficiency is not enough. In order to quantitatively study the influencing factors of cement displacement efficiency in horizontal wells, provide guidance suggestions for laboratory experiments and field cementing construction, improve cementing quality and reduce the cost of laboratory experiments and cementing construction, this paper aims at horizontal wells. The force of drilling fluid microelement is analyzed by microelement analysis method. According to the equilibrium condition of drilling fluid displacement in stable state during cement injection, a model for calculating the thickness of drilling fluid retention layer in eccentric annulus in horizontal well is established. The effects of eccentricity, inclined angle, yield stress of drilling fluid and rheological parameters of cement slurry on the displacement efficiency of cement injection in horizontal wells were analyzed. The results show that when the casing eccentricity increases, the displacement efficiency at the narrow annulus decreases sharply, which seriously affects the cementing quality, and when the static shear force of the drilling fluid increases, the remaining layer thickness of the drilling fluid increases. The thickness of the remaining layer in narrow annular gap increases obviously, so the casing should be kept in the middle and the static shear force of drilling fluid should be reduced as much as possible in cementing. In order to obtain good cementing quality in cementing operation, the parameters changed with the cementing time and the stability of the bottom hole environment must be strictly controlled. In the traditional cement injection design, the calculation of the cementing flow process is simplified. Only the judgment of annular flow in ideal condition, the calculation of downhole pressure and pump pressure, etc., but the influence of U-tube effect caused by the density difference of fluid in the well is neglected. At present, the calculation model of U-tube effect of cement injection is only suitable for the process of cement injection in straight wells, but there is no research on the U-tube effect of cement injection in horizontal wells. This paper aims at the flow process of cement injection in horizontal wells. The flow process of cement injection in horizontal wells is studied by using Euler differential equation, and the calculation model of U-tube effect in horizontal wells is obtained. The calculation results of cement injection flow in horizontal wells show that the U-tube effect will occur in horizontal wells, which will affect the flow velocity of cementing in annulus, reduce the turbulent displacement time of cement slurry to drilling fluid and reduce the displacement efficiency of cement injection. Based on the calculation model of displacement efficiency of horizontal well and the calculation model of U-shaped pipe effect in horizontal well, based on SQL Server 2008 database and WPF framework, the calculation software of horizontal well cementing flow process is developed in C # language under the development platform of Visual Studio 2013. On the basis of the conventional cement injection design, the software focuses on the calculation of the displacement efficiency of cement injection in horizontal wells and the in-well flow process of the whole cement injection. The software runs stably and the calculation results of each model are reliable. It can be used to calculate and predict the flow process in cement injection wells in horizontal wells, which provides theoretical basis and reference for field construction and laboratory experiments.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE256.5

【参考文献】