复杂结构井钻柱解卡参数分析

Parametric Analysis of Drill String Unfreezing in Complex Structure Well

在复杂结构井解卡过程中,为了优化旋转上提和旋转下放的解卡参数,确保载荷能够最大限度地传递至卡点,分析了遇卡钻柱与正常钻柱在摩阻扭矩计算方面的差异,探讨了旋转、减阻器和卡点深度对遇卡钻柱轴向力传递效率的影响。实例计算和分析结果表明,遇卡钻柱的摩阻系数与变形量存在耦合关系,且随载荷分布、卡点深度等参数的变化而变化;钻柱旋转可以提高载荷传递效率,下放解卡时旋转降阻作用更加明显;旋转上提解卡时卡点拉力随井口拉力的增加而增加,旋转下放解卡时最大卡点压力可能不是悬重放空时,通过优化解卡参数可以最大程度地增加解卡载荷;旋转上提和旋转下放解卡过程中,减阻器会降低最优解卡参数下的最大卡点载荷,减阻器轴向摩阻系数越大越不利于解卡作业。

In the process of complex structure well unfl＇eezing, the freeing parameters for rotating pulling and lowering should be optimized and the transmission of load to tire sticking point in the greatest possible degree shouhl be ensured. Therefore, the difference between stuck drill string and normal drill string in friction torque calculation was analyzed; the eitect of rotation and drag reducer＇ s sticking point depth on the axial three transmission efficien- cy of stuck string was discussed. The example calculalion and analysis show that there is a coupling relation between the t）＇ietion coefficient and defurmation of stuck string and it changes with the parameters such as load distribution and slicking point depth. Drill string rotation can improve load transmission efficiency. The rotating resistance reduc- tion is more noticeahle in lowering and unfreezing. The maximum sticking point pressure may not be in string sus- pending weight relief in unfreezing by rotating lowering. Optimizalion of unfreezing parameters can increase freeing load to a maximum. In the process of rotating pulling and lowering, the drag reducer will reduce the maximum stick- ing point load under the optimal unfreezing parameter. The larger the axial friction coefficient of the reducer, the more unfhwrahle to unfreezing.