Abstract: In recent years，the large-scale development of unconventional oil and gas resources in China has led to a sharp increase in the number of horizontal wells. Due to the lack of scientific and systematic understanding on horizontal well bore cleaning，drilling process in horizontal section often appears stuck，completion ahead of schedule，disability of running casing to the predetermined well depth. In addition，poor wellbore cleaning can also cause very high implicit costs，including ROP controlling，increasing time consumption of reaming，circulation，and tripping. In this paper，by clarifying the mechanism of cutting migration in different sections of horizontal wells，analyzing the key elements of wellbore cleaning and proposing a method to evaluate wellbore cleaning by monitoring actual drilling friction，a set of efficient horizontal wellbore cleaning technology has been formed. Field practice in Mahu and Jimsar shale oil has verified the technical theory based on field data，which can guarantee the cleanness of horizontal section under the conditions of existing domestic equipments and instruments，and greatly ruduce inefficient production time consumption such as mud circulation and wiper tripping to increase speed and efficiency.

Key words: horizontal well, wellbore cleaning, cutting migration, friction, inefficient production time

摘要： 近年来，国内大规模开发非常规油气资源，水平井部署数量急剧增加，由于对水平井井眼清洁缺乏科学、系统地认识，水平段钻进过程中经常出现卡钻、提前完钻、套管无法下至预定井深等问题；另外，不良的井眼清洁也会导致非常高的隐性成本，包括控制机械钻速、增加划眼、循环、起钻时间等。通过明确水平井不同井段岩屑运移机理，分析井眼清洁的关键要素，提出一种通过监测实钻摩阻评价井眼清洁的方法，形成一套高效的水平井井眼清洁技术。在玛湖及吉木萨尔页岩油等区域现场实践，根据现场实测数据验证了该套技术理论的正确性，可以在国内现有设备及仪器的条件下，保障水平段井眼清洁，大幅缩短循环、通井等低效生产时间，协助现场水平井提速提效。

关键词: 水平井, 井眼清洁, 岩屑运移, 摩阻, 低效生产时间