Abstract: An anti-whirl technology keeping the lateral forces and cutters balanced on PDC bit for slim-hole drilling is proposed.The basic principle of the conclusion is discussed,and a method of balanced bit design is introduced.A new kind of 114mm anti-whirl polycrystalline diamond bit for drilling slim holes is successfully developed.The excellent performances of the bit are confirmed by drilling tests in Dagang Oil Field of China.The analysis on abrasion of the bit indicates that there is no obvious fracture damage during drilling period,which shows that the self-balanced design has better anti-whirl property than the conventional design.

Key words: PDC bit, slim hole, balanced design, cutter, mechanical balance, whirl

摘要： 针对小井眼PDC钻头的实际工作条件,提出了在小井眼钻井中具有普遍意义的PDC钻头的横向力自平衡抗回旋技术.分析了钻头的受力状态与钻头回旋运动之间的关系,并对自平衡抗回旋技术的基本原理、设计方法和技术准则作了阐述.将该技术应用到小尺寸PDC钻头设计中,开发出可在直井、定向井以及水平井等各种小井眼钻井中使用的新型直径为114mmPDC钻头.简要介绍了该钻头的设计原理、结构特点和重要的技术参数.小井眼PDC钻头在大港油田直径为140mm套管开窗侧钻井的钻井工程中取得了良好的技术效益和经济效益.磨损分析结果表明,切削齿磨损速率低,磨损量均衡,聚晶金刚石层未见明显的脆性崩裂,具有良好的抗回旋性能.

关键词: PDC钻头, 小井眼, 平衡设计, 切削齿, 力平衡, 回旋