连续管钻塞水平段铁屑运移机理研究

针对水平井段连续管钻磨桥塞时铁屑运移规律尚认识不清，沉积的铁屑堆积在井下工具周围而导致卡钻的问题，在欧拉坐标系下考虑相间滑移速度以及铁屑流参数，建立了三维井眼环空铁屑运移模型，采用Standard κ－ε湍流模型及SIMPLEC算法进行数值计算，研究了环空偏心度、钻塞液排量、铁屑直径、钻塞液粘度和铁屑体积分数对水平段铁屑运移的影响，得到了环空铁屑体积分数和固定铁屑床高度的分布规律。研究表明:增大钻塞液排量、减小铁屑直径、减小环空偏心度、增大钻塞液粘度和减小铁屑体积分数，可提高连续管钻塞水平段铁屑运移效率。水平段铁屑运移机理研究可为连续管钻磨桥塞卡钻问题的解决提供技术支持。

Study on migration mechanism of iron filings in horizontal section during drilling plug with coiled tubing

Aiming at the problems that the migration laws of iron filings in horizontal well section during drilling and milling the bridge plug with coiled tubing (CT) have not been understood clearly, and the accumulated iron filings around the downhole tools will lead to the sticking, a three dimensional model on migration of iron filings in annulus space was established considering the interphase slip velocity and the parameters of iron filings flow under the Euler coordinate system. The numerical calculation was carried out by using the Standard κ－ε turbulence model and the SIMPLEC algorithm, then the influence of the eccentricity of annulus, the flow rate of drilling plug fluid, the diameter of iron filings, the viscosity of drilling plug fluid and the volume fraction of iron filings on the migration of iron filings in horizontal section was studied, and the distribution laws of the volume fraction of iron filings in annulus and the height of fixed iron filings bed were obtained. The results showed that the migration efficiency of iron filings in horizontal section during drilling plug with coiled tubing can be improved when increasing the flow rate of drilling plug fluid, decreasing the diameter of iron filings, decreasing the eccentricity of annulus, increasing the viscosity of drilling plug fluid and decreasing the volume fraction of iron filings. It can provide technical support for solving the problem of sticking when drilling and milling the bridge plug with CT.