摘要：Flexible tool drilling (FTD) technology is an efficient and cost-effective method with a short construction period for sidetracking operations. Unlike conventional drilling pipes, flexible drilling tools consist of a series of short pipes connected by universal joints. The buildup radius ranges between 3 m and 5 m. A more accurate prediction of the buildup rate is necessary to reduce uncertainties in tool design and drilling process set. In this paper, we investigate the influence of structural and mechanical parameters on the buildup rate (BUR) of flexible drilling tools. A semi-analytical model was developed, achieving an accuracy of ±0.3 m after field validation with six FTD branches. The model clarified key relationships among the BUR, load transfer, and trajectory characteristics and analyzed the effects of parameters such as maximum bending angle, pipe length, bit anisotropy, friction, and axial force on the top flexible pipe. The study demonstrates that higher bit anisotropy improves directional control and increases the BUR, although it also raises mechanical loads, particularly side forces. The optimal bit anisotropy index should not be lower than 0.7. Shorter pipe lengths enable sharper directional changes but increase mechanical losses. The optimal parameters are recommended as a bit anisotropy above 0.8, a pipe length of 0.15–0.2 m, an axial force of 4–6 tons, a maximum bending angle of 3°, and a minimized friction factor. Our research also concludes that axial force should be greater than 4 tons to ensure sufficient weight on bit (WOB) and pipe string stability. Furthermore, the friction factor primarily affects mechanical load distribution along the pipes rather than trajectory. This research provides theoretical support for the trajectory control of flexible drilling tools and enables their adaptation to various application scenarios. Copyright ? 2025 Society of Petroleum Engineers.

ISSN号：1086-055X

卷、期、页：卷30期4：1789-1805

发表日期：2025-04-01

影响因子：0.000000

期刊分区（SCI为中科院分区）：三区

收录情况：SCI（科学引文索引印刷版）,EI（工程索引）,SCIE（科学引文索引网络版）

发表期刊名称：SPE Journal

通讯作者：刘鑫,陈晗,彭榆烜,彭榆烜

第一作者：黄中伟,武晓光,李根生,史怀忠

论文类型：期刊论文

论文概要：刘鑫,黄中伟,武晓光,李根生,史怀忠,陈晗,彭榆烜,彭榆烜，Prediction of Buildup Rate for an Ultrashort-Radius Well Trajectory Drilled with a Flexible Drilling System: A Semi-Analytical Solution，SPE Journal，2025，卷30期4：1789-1805

论文题目：Prediction of Buildup Rate for an Ultrashort-Radius Well Trajectory Drilled with a Flexible Drilling System: A Semi-Analytical Solution