超短半径转向滑道的阻力建模及布轮设计

超短半径的转向过程是带有初始应力的弹塑性弯曲过程,由于塑性弯曲的非保守性,钻杆最终的形态及施加在其上的载荷与加载顺序有关,实际计算超短半径钻杆转向阻力时要考虑载荷施加顺序的影响。通过对超短半径钻杆转向过程的受力分析,建立了滑道的分段阻力模型,提出用滑道阻力系数评定滑道设计的优劣。结果认为,副弯曲段的阻力特性模数并不因为转向角度小而有明显降低,要重视其结构设计;降低系统摩擦因数μ值及保证钻进中μ值的稳定,是保证转向器工作可靠的要点。

Resistance modeling and wheel-distribution design for ultra-short radius diverting slide

The diverting process of ultra-short radius is an elastic-plastic bending process with initial stress. The final configuration of drill pipe and the load applied on it are related to the sequence of loading due to non-conservativeness of plastic bending. The influence of loading sequence should be considered when calculating the diverting resistance of ultra-short radius drill pipe. By performing the force analysis of the diverting process of ultra-short radius drill pipe, the stepwise resistance model for the slide is established, and it is put forward that the resistance factor of slide should be used to evaluate the design level of slide. The result considers that the resistance feature module of the sub bending section would not be decreased significantly due to the small diverting angle. The structure design should be emphasized. And decreasing system μ value and maintaining a stable μ value during the drilling are the key points for ensuring the reliable work of whipstock.