井下动力驱动的旋冲钻井工具设计计算与试验

Design Calculation and Experimental Study on Downhole Motor Driven Rotary Percussion Drilling Tool

设计了一种基于井下动力驱动的旋冲钻井工具,实现两种破岩机理相结合,提高整体破岩效果。采用螺杆或涡轮钻具作为旋转动力源,利用由一对空间凸轮机构组成的冲击发生机构带动上凸轮及其他从动件上行,下行的过程中,从动件冲击下凸轮,下凸轮将冲击能传递给钻头,实现对岩石的体积破碎。利用Solidworks Premium 2012软件计算了空间凸轮机构在不同载荷作用下的应力分布情况,上凸轮和下凸轮在承受最大设计载荷时的安全系数分别为3.69和2.36,均大于需用安全系数,设计安全可靠。工具冲击性能测试得到了冲击力、冲击频率与钻压、排量之前的关系,试验结果表明,其动力特性参数满足现场复合钻进工况要求。进行了现场试验,该工具具有较好的提速效果,同比提速40%以上。

A type of rotary percussion drilling tool based on downhole motor drive is designed to realize the combined action of the two types of rock breaking mechanism,and to improve the overall rock breaking effect.Using displacement motor or turbo drill tool as the rotation power source,the upper cam and its followers are driven upward by an impact mechanism consisting of a couple of spatial cams,impacting the lower cam during the downward process.The impact energy is transmitted to the drill bit by the lower cam to realize volume fragmentation of the rock.Stress distribution under different loads is analyzed for the mating cam mechanism.Safety coefficients of upper and lower cams under maximum load are 3.69 and 2.36 respectively.Both are greater than the allowable safety coefficients,which proved the design safety and reliability.Relation of impact force and impact frequency versus WOB and flow rate is obtained from tool impact parameter test.Test result shows that tool's power output performance parameters meet requirements of field work condition of compound drilling.Field trials are also carried out,which show preferable ROP raising effect,improved by over 40%comparatively.