水平井修井管柱屈曲影响因素仿真研究

SIMULATION STUDY ON AFFECT FACTORS OF WORKOVER STRING BUCKLING IN HORIZONTAL WELL

准确了解修井作业过程中井底钻压及管柱屈曲变化规律对于高效、安全修井作业具有重要的意义。根据数值仿真原理及修井管柱受力特性,建立了修井作业管柱有限元模型,分析了管柱在井筒中的受力情况,模型计算结果与现场实验数据吻合较好。通过了水平作业管柱有限元模型,对影响水平井管柱屈曲临界载荷的摩擦因数和环空间隙等因素进行了分析。研究结果表明:摩擦因数越大其正弦和螺旋屈曲临界载荷都随着增大,且螺旋屈曲临界载荷对摩擦因数更敏感;环空间隙变大,会导致管柱的屈曲载荷减小,且当环空间隙大于35 mm时,管柱的螺旋屈曲临界载荷小于正弦屈曲临界载荷。

Understanding the WOB and the law of tubular buckling is significant to handle workover operation efficiently and safely. Based on the simulation theory and the characteristics of workover string dynamics,a finite element model is established for the workover string. Then,the tubular in the wellbore is simulated by the model,and the simulation result is highly coincide with the experiment result. The strings in horizontal well is built,and the critical buckling load is analyzed in different friction coefficient and different annular clearance. The results show that： the sinusoidal buckling load and helical buckling load will increase with the friction coefficient,and the helical buckling load increase more rapidly; while with the increase of annular clearance,the buckling load will decrease. When the annular is larger than 35 mm,the helical buckling load is even smaller than sinusoidal buckling load.