双台肩技术在小尺寸钻铤上的应用研究

Application and Research of Double Shoulder Connection on the Small Size Drill Collar

对塔里木油田120.65 mm(43/4英寸)钻铤断裂频繁的米兰1井和哈6井进行了分析,认为在超深井小井眼钻进中提高钻铤螺纹抗扭强度是预防钻铤失效的关键。对120.65 mm(43/4英寸)钻铤NC35螺纹加工LE螺纹、应力槽、双台肩后进行了实物抗扭性能试验,证实双台肩钻铤具有很好的抗扭性能。有限元计算表明,双台肩螺纹具有较低应力水平。根据现场使用效果分析,双台肩技术的使用有效地降低了钻铤断裂失效数,值得在小尺寸钻具上推广应用。

Based on frequent fracture of Drill Collar in 4 3/4 inch at Tarim Oilfield and analysis of the accident-prone Wells in Milan land Ha 6 wells, it is confirmed that raising torsional strength of Drill Collar in 4 3/4 inch at slim-hole and ultra deep drillings of Tarim Oilfield is the key to prevention of thread failure. After processing LET thread, stress groove and double shoulder connection for the NC35 thread of Drill Collar in 4 3/44 inch, torsion tests were done. It is concluded that double shoulder connection has best torsional performance. Through FEM calculation, double shoulder connection has lower stress level. According to analysis of the application from the site, double shoulder connection reduces failure effectively. It is worth popularizing in the small size drilling tool.