连续管外壁冲蚀磨损规律

Erosion wear law of coiled tubing outer wall

基于液-固两相流和冲蚀理论,建立环空携砂压裂液冲蚀磨损连续管外壁模型,采用Grant和Tabakoff模型求解砂砾冲蚀速率,并借助实验数据验证CFD数值模型;利用该模型研究弯曲连续管与直连续管、质量流量、砂砾粒度、压裂液注入排量及压裂液黏度对连续管外壁冲蚀磨损规律影响。数值计算结果表明:弯曲连续管冲蚀磨损严重,且最大冲蚀磨损发生在弯曲连续管与套管形成的小间隙处;随质量流量的增加,连续管冲蚀磨损愈加严重;砂砾粒度对连续管外壁冲蚀磨损影响敏感;随着注入流量的增加,连续管外壁冲蚀磨损呈快速增长趋势;压裂液黏度的增加,最大冲蚀率呈现下降趋势。

Based on the fluid and solid two-phase flow dynamics and erosion theory, sand-carrying erosion model was established for outer wall of coiled tubing （CT） in horizontal section. The erosion rate of sand particle was calculated through Grand and Tabakoff formula. The calculation result was verified with the experimental data for the computational fluid dynamics （CFD） numerical model. Then, this model was applied to study the erosion law of outer wall of CT, such as curved tube and straight tube, the mass flow, the size of sand particle, the inject pressure, the volume of fracturing fluid injection and the viscosity of fracturing fluid. The result shows that the erosion of curving CT is more serious than that of straight CT, and also the erosive wear is the most serious in the small gap between the CT and the casing. With the increase of mass flow, erosion rate of outer wall of CT increased dramatically. The size of sand particle has great effect on the erosion of outer wall of CT. The erosion rate of the CT rapidly grows with the increase of fluid injection volume.