基于冲蚀-动网格耦合的绕丝筛管冲蚀过程数值模拟

Numerical simulation of the erosion process of wire wrapped screen based on erosion-dynamic grid coupling

孙岩 楼一珊 曹砚峰 文敏 翟晓鹏 赵轩康

SUN Yan LOU Yishan CAO Yanfeng WEN Min ZHAI Xiaopeng ZHAO Xuankang

长江大学石油工程学院 中海油研究总院有限责任公司

School of Petroleum Engineering, Yangtze University, Wuhan 430100, Hubei, China CNOOC Research Institute Co., Ltd., Beijing 100028, China

砂砾对绕丝筛管的反复冲刷并造成筛管的筛网孔径变形等局部破坏，是最终造成绕丝筛管防砂失效的主要原因。对绕丝筛管冲蚀破坏的理论研究既要考虑筛管的质量损失，也要考虑筛网变形对绕丝筛管的防砂影响。基于冲蚀-动网格耦合理论，建立了CFD有限元模型，通过Mclaury磨损预测模型与Realizable k-\begin{document}$\varepsilon $\end{document}湍流模型建立了绕丝筛管液-固两相流模型，分析防砂过程中砂砾对绕丝筛管的冲蚀进化影响。同时分析了流速、砂粒直径、含砂质量分数对筛管冲蚀磨损的影响规律。通过数值模拟结果和曲线拟合方法，建立了未堵塞工况下的冲蚀预测模型。研究发现：绕丝筛管冲蚀变形区域主要集中在绕丝下游一侧、绕丝正上方与基管孔周围，并随时间延长向外扩散，直观表示出绕丝筛管冲蚀破坏开始于何处；绕丝在冲蚀进化过程中，冲蚀变形量最高且随时间延长，与比冲蚀率呈负相关，与试验结果平均误差小于2%。在不考虑砂粒堵塞工况(粒径小于123 μm)下，绕丝筛管冲蚀率随流体流速增加呈指数增大，随含砂质量分数及砂粒直径的增加呈线性增大。拟合出的计算公式与数值模拟数据基本一致。因此，基于冲蚀-动网格耦合的冲蚀数值计算结果对绕丝筛管的寿命预测具有参考意义。

Sand erodes the wire wrapped screen again and again and results in its local damage (e.g. the deformation of screen mesh size), which is main cause leading to the sand control failure of wire wrapped screen ultimately. At present, the theoretical studies on the erosion destroy of wire wrapped screen generally consider the mass loss of the wire wrapped screen only, but not the influences of screen mesh deformation on the sand control effect of wire wrapped screen. In this paper, the CFD finite element model was established based on the theory of erosion-dynamic mesh coupling, and the liquid-solid two-phase flow model of wire wrapped screen was established by means of Mclaury abrasion forecast model and Realizable - turbulent model. Then, the influence of sand on the erosion evolution of wire wrapped screen in the process of sand control and the influential laws of flow velocity, sand particle diameter and sand mass fraction on the erosion and abrasion of wire wrapped screen were analyzed. Finally, the erosion forecast model of working condition without sand blockage was established by using numerical simulation results and curve fitting method. It is indicated that the erosion deformation zones of wire wrapped screen are mainly distributed at the downstream side of wrapping wire, right above the wrapping wire and around the hole of base pipe, and extends outward over time, which directly shows the starting position of the erosion destroy of wire wrapped screen. During the erosion evolution of the wrapping wire, the erosion deformation is the maximum and negatively correlated with the specific erosion rate over time and its average error from the experimental results is less than 2%. Under the working conditions without sand blockage (particle diameter ＜123 μm), the erosion rate of wire wrapped screen increases exponentially with the increase of fluid flow velocity and linearly with the increase of sand mass fraction and sand particle diameter. The fitted calculation formula and the numerical simulation data are basically consistent. In conclusion, the numerical calculation results based on erosion-dynamic mesh coupling are of reference significance to the life forecast of wire wrapped screen.

10.13639/j.odpt.2021.02.005