脉冲射流式岩屑床清理工具的研究

针对大斜度及水平井段，岩屑极易沉积在井筒底部形成一定高度的岩屑床，使得钻杆被埋没，造成钻杆摩阻增大、钻具断裂等问题，设计一种射流式岩屑床清洁工具，基于液固两相流理论，建立三维射流式清洁工具与普通携岩钻杆的仿真模型，并利用Fluent分析射流式清理工具的喷嘴喷射角度、喷嘴流速、岩屑粒径、钻井液排量等参数变化对环空井筒内岩屑体积分数及岩屑质量的影响规律。结果表明：增加脉冲射流式工具后，环空内的岩屑沉积量明显减少，在钻杆转速为80 r/min时，最佳的喷嘴角度为90°；增加喷嘴流速及钻井液排量都可以降低环空内的岩屑量；随着岩屑粒径的增加，环空内岩屑沉积更多。该工具能够降低沉积在环空内的岩屑质量，提高岩屑的运移能力。

Research on the Cleaning Tool of Pulse Jet Cuttings Bed

For large incline and horizontal section, cuttings are easy to deposit at the bottom of wellbore and form cuttings bed with a certain height, which makes drill pipe buried, resulting in increasing friction resistance of drill pipe and fracture of drill pipe.A jet cuttings bed cleaning tool was designed based on the liquid-solid two-phase flow theory. The simulation model of 3D jet cuttings cleaning tool and ordinary rock-carrying drill pipe was established. Fluent was used to analyze the influence of parameters such as nozzle injection angle, nozzle velocity, cuttings particle size and drilling fluid displacement on cuttings volume fraction and cuttings quality in annulus wellbore. The results show that the cuttings deposition in the annulus decreases significantly with the addition of the pulsed jet tool, and the optimal nozzle angle is 90° at the drill pipe speed of 80 r/min. Cuttings quality in annulus can be reduced by increasing nozzle velocity and drilling fluid displacement. As the cuttings particle size increases, more cuttings are deposited in the annulus. This tool can be used to reduce the cuttings deposited in the annulus and improve the cuttings migration ability.