基于可控弯接头指向角的PDC钻头破岩效率分析

Rock Breaking Efficiency Analysis of PDC Bit Based on Pointing Angle of Controllable Bent Sub

为了提高指向式井下闭环可控弯接头的破岩效率,利用ABAQUS软件对PDC钻头在加压回转载荷作用下,连续破碎砂岩进行动力学仿真分析,并利用Python语言对ABAQUS软件进行二次开发,生成参数化定义插件,以达到优化仿真流程的目的。研究旋转导向钻进过程中不同指向角大小对PDC钻头破岩效率的影响,得到了指向角分别为0.0°、2.5°和5.0°对破岩体积、钻头进尺、破岩速度及钻头扭矩的影响规律。研究结果表明:可控弯接头在导向钻进整个过程中,不同指向角变化对钻头扭矩作用并不明显;但当指向角为0.0°时,PDC钻头破岩效率最高,钻头进尺深度最大;指向角为5.0°的破岩效率明显比2.5°的破岩效率要高;指向角越大,其钻头轴向钻进速度波动越大。研究结果对于井下闭环可控弯接头的实际操作以及钻头破岩效率的提高具有一定的理论指导意义。

In order to improve the rock breaking efficiency of the directional downhole closed-loop controllable bent sub,the ABAQUS software was used to conduct dynamic simulation analysis on the continuous sandstone breaking by the PDC bit under the pressurized rotary load,and the Python language was used to conduct secondary development on the ABAQUS software to generate the parameterized definition plug-in,so as to achieve the objective of optimizing the simulation process.The effect of different pointing angles on rock breaking efficiency in rotary navigation drilling was studied,obtaining the effect of 0.0°,2.5°and 5.0°pointing angles on rock breaking volume,bit footage,rock breaking speed and bit torque respectively.The study results show that in the whole process of navigation drilling by controllable bent sub,the effect of different pointing angles on bit torque is not obvious;however,when the pointing angle is 0.0°,the PDC bit has the highest rock breaking efficiency and the largest footage depth;the rock breaking efficiency of 5.0°pointing angle is obviously higher than that of 2.5°pointing angle;and the greater the pointing angle,the greater the axial drilling speed fluctuation of the bit is.The study results have certain theoretical guiding significance for the actual operation of downhole closed-loop controllable bent sub and the improvement of rock breaking efficiency of drill bit.