套管钻井中连接螺纹力学分析及设计计算

Mechanics analysis and design of connecting thread in casing drilling

在套管钻井中,套管偏梯形锥螺纹连接承受动载转矩,经常发生胀扣、黏扣失效.提出了一种新型的套管连接螺纹结构,采用内端面和锥螺纹共同产生预紧力;建立了套管钻井用连接螺纹的力学模型,以预紧力作用下连接螺纹的变形协调方程为基础,经求解得到了每一扣螺纹牙承受的轴向载荷.340 mm套管偏梯形锥螺纹连接的计算结果表明,在20 kN.m上扣转矩作用条件下,其优选结构参数:锥螺纹小端中径为328.787 mm,内螺纹体外径为350 mm.

In casing drilling,casing taper thread will appear casing gluing or expanding when it is subjected to dynamic torque.According to drill pipe and drill collar connecting thread,casing drilling connecting thread is improved and redesigned.The mechanical model of the redesigned connecting thread of casing connecting is put forward by the author.By the method,main factors that affect the distribution of the stress acting on the connecting thread are studied.On the basis of a compatibility equation of casing deformation derived from mathematical method,the axial load of each casing taper thread is calculated by solving the equations put forward by the author.A φ340 casing taper thread is designed and calculated according to the equation,and the optimizing parameters under 20 kN·m of make-up torque are obtained.