水平井和斜井井眼清洁技术研究进展及展望

水平井钻井技术的进步有利于开发常规和非常规油气储层，然而，与水平段岩屑清除相关的井筒的不稳定性和井眼清洁困难严重制约了钻井生产。井筒岩屑清除效率低下会导致摩阻和扭矩增加、管道卡住，严重时可导致井漏等钻井事故。首先，分别从井眼清洁机理和井眼清洁主要影响因素（钻井液流变性、钻具转速、井角、岩屑尺寸、钻井液密度和流速等）分析综述了水平井和斜井岩屑沉积的成因和适用于现场生产的技术参数。其次，针对水平井和斜井井眼清洁困难分别从国内外钻井液技术和井眼清洁工具两个方面阐述了岩屑清除方法与机理。最后，对水平井和斜井井眼清洁发展方向进行了展望，为未来井眼清洁技术提供了参考。

Hole Cleaning Technology for Horizontal and Deviated Drilling: Progress Made and Prospect

Although progresses made in horizontal drilling have been very beneficial to the development of conventional and unconventional oil and gas, two factors related to the cleaning of drilled cuttings from the horizontal section of a well seriously hinder the drilling operation. One of the factors is borehole wall instability, and the other is the difficulties in wellbore cleaning. Inability to remove drilled cuttings from a wellbore in a timely manner often results in increases in friction and torque on the downhole drill string, and the frequency of pipe sticking, and the worse is the simultaneous occurrence of lost circulation. First in this paper, the causes of cuttings bed formation and technical parameters for field operation are analyzed and summarized from two aspects, which are hole cleaning mechanisms and the main factors affecting hole cleaning (mud rheology, pipe rotation, hole inclination, sizes of the drilled cuttings, mud weight and flowrate etc.). Second, the methods and mechanisms of cuttings removal were systematically elaborated from the drilling fluid technologies and hole cleaning tools available both in China and abroad to help deal with the difficulties in hole cleaning in deviated and horizontal drilling. Finally, the development direction for horizontal and deviated hole cleaning technology is prospected to provide a reference for the hole cleaning technology development in the future.