钻铤螺纹粘扣失效有限元分析

钻铤在井眼中受力复杂,在正常的旋转钻井过程中要承受预紧、拉压、扭转、弯曲、内外压力等多种静载荷或动载荷,此外,还要受到钻井液和地层介质的腐蚀作用。因此钻铤失效事故频繁发生,严重地影响了钻井工程的正常进行。钻铤螺纹粘扣是主要失效形式之一,本文建立了普通API钻铤螺纹连接部位的有限元模型,并用有限元方法分析了在不同钻压条件下的应力分布情况,确定了引起这种失效形式的主要因素是由于井深加大产生的压载不断增大。在钻铤材料确定的情况下,只能通过提高钻铤本身抗粘扣性能来避免发生这种失效。

Failure Finite Element Analysis of Thread Gluing on Drill Collar

The force of the drill collar in the drill hole is complex. During the normal rotary drilling process, there are various static and dynamic loads on the drill collars, such as precompact force, tensile and compression force, torsion, bending, internal and external pressures, and so on. In addition, the drill collars will suffer corrosive action from drilling fluid and stratum medium and so on. Therefore, the failure accidents on drill collar are often occurred, these accidents affect the normal drilling working order. The thread gluing accident on drill collar is one of the main failure modes. In this article, built a finite element analysis model for the screw connecting position of common API drill collars was built, and then the stress distribution under different drilling pressures was analyzed by finite element analysis. After that this paper found the main reason of the failure, it is the ballast increasing with the rising of well depth. While the material of the drill collars is certain, the failure accident can be avoided only by improving the anti-galling properties of the drill collars.