新型恒扭矩工具动力学模型与降黏机理研究

Dynamic model and Sticky Slip reduction mechanism of a new constant torque tool

钻柱黏滑作为钻柱动力学中的关键问题,在深井、大位移水平井中,黏滑可能导致钻具性能下降,乃至工具失效引发井下事故。因此,降黏技术的研究,对于有效提高机械转速,缩短建井周期,保证安全作业具有重要指导意义。基于纵向与扭转振动耦合的黏滑过程动力学模型,以提出的新型恒扭矩工具为研究对象,进行其工作机理研究,利用建立的理论方法,根据生产数据进行算例分析,包括纵向与扭转动力学结果,并与现场数据进行对比分析。研究结果表明:由于新工具纵扭耦合产生的恒扭矩效果,在软硬交错的岩层区进行钻进破岩时,可有效减小钻具扭矩波动,避免出现滞动现象,使有效破岩行为持续稳定进行。所提出的新型恒扭矩工具可为降黏减摩、提速增效技术提供参考,建立的理论模型可为新型钻井条件下的钻柱动力学发展起推动作用。

As a key problem in drill string dynamics,drill pipe stick slippage in deep wells and large displacement horizontal wells may cause drilling tool performance dropping and tool failure to lead to underground accidents.Therefore,studying sticky slip reduction technology has important guiding significances for effectively improving machinery’s rotating speed,shortening well-built period and ensuring safe operation.Here,based on the dynamic model of sticky slip process with longitudinal-torsional vibration coupled,a new constant torque tool was proposed.This new tool was taken as the study object to study its working mechanism.According to production data,the theoretical method established was used to do example analysis including longitudinal and torsional dynamic results.The example results were compared with the field data.The study showed that due to the constant torque effect produced by the new tool with longitudinal-torsional coupling,the torque fluctuation of the new tool can be effectively reduced to avoid the hysteresis phenomenon and make effective rock breaking behavior be continuous and stable when drilling for rock breaking in soft and hard inter-leaving zones.The proposed new constant torque tool provided a reference for improving techniques of sticky slip reduction and increasing speed and efficiency.The established theoretical dynamic model promoted the development of drill string dynamics under new drilling conditions.