近几年来 ,连续油管 (CT)钻井技术迅速发展 ,但是连续油管钻井作业中仍然面临着一个严峻的挑战 ,即钻屑的有效携带问题 ,尤其是在水平井中。本文概述了连续油管钻井过程中钻屑的携带问题以及目前的解决方法 (包括钻井液的选择、流速及作业技术 ,如短距离起下钻和泵送粘稠钻井液段塞 )。结果表明 :在很多情况下 ,紊流下泵送低粘度钻井液时井眼的清洗能力比在层流下泵送高粘度钻井液时井眼的清洗能力要强。在层流下依靠粘稠钻井液清洗井眼已经证明是一种无效的方法 ,因为CT管柱不能旋转不足以搅起成层的钻屑。相比较而言 ,在紊流高流速下钻井液的井眼清洗能力更有效 ,但由于连续油管内摩擦压力较高 ,难以获得这种流态 ,因此 ,在连续油管钻井过程中钻屑层几乎总是存在。这是导致弥补作业、增加卡钻风险及不能达到所要求进尺的主要原因。本文介绍了两种了解井眼清洗能力的新方法 :第一种方法是 ,对层流 ,钻屑颗粒在环空中沉降前移动的距离用Stoke定律和流动时的区域粘度计算。这种分析方法用于优选泥浆和进行通井。将该模型应用于高强度 -低剪切速度 -低粘度 (LSRV)凝胶 ,结果表明凝胶在套管内携带钻屑能力良好 ,但在狭窄的水平井眼环空中的井眼清洗能力极差。第二种方法是 ,引入了一个更全面的概念———AV In recent years, coiled tubing (CT) drilling technology has been rapidly developed, but coiled tubing drilling operations still face a serious challenge, namely the effective carrying of cuttings, especially in horizontal wells. This article provides an overview of drill cuttings carryover and current solutions (including drilling fluid selection, flow rates, and operating techniques such as short distance drilling and pumped viscous drilling fluid slugs) for coiled tubing drilling. The results show that in many cases, wellbore cleaning capability is better when pumping low viscosity drilling fluid under turbulent flow than when pumping high viscosity drilling fluid under laminar flow. Relying on viscous drilling fluids to clean boreholes in laminar flow has proven to be an ineffective method because the CT columns can not be rotated enough to stir stratified drill cuttings. In comparison, the wellbore cleaning capability of drilling fluid is more effective at turbulent high flow rates, but it is difficult to obtain this flow regime due to the high frictional pressure within the coiled tubing. Therefore, during the coiled tubing drilling process, Always exist. This is the main reason that leads to job recovery, increased risk of stuck pipes and inability to achieve the required footage. This article presents two new ways to understand wellbore cleaning capabilities: The first is to calculate the distance traveled by laminar flow and drill cuttings before they settle in the annulus using Stoke’s law and the area viscosity at flow. This method of analysis is used to optimize slurries and pass through wells. Applying this model to High Strength - Low Shear Rate - Low Viscosity (LSRV) gels, the results show that the gel has good ability to carry drill cuttings within the casing, but poor borehole cleaning capability in narrow horizontal well annuli . The second method is to introduce a more comprehensive concept --- AV