PDC钻头旋转流场与非旋转流场的模拟对比研究

Comparative Study on Simulation of Rotating Flow Field and Non-rotating Flow Field of PDC Bit

在钻井过程中,当地层较软且含有大量黏度较高的物质时,如果不能及时排出岩屑,容易产生泥包,从而降低钻头钻速。对PDC钻头的旋转流场与非旋转流场进行数值模拟仿真,并通过DPM模型模拟岩屑在井底的运移。研究表明:岩屑的运移轨迹在旋转流场与非旋转流场的环空部位存在明显差异;旋转流场岩屑侵蚀刀翼背部较多,非旋转流场岩屑侵蚀齿面较多;刀翼冠部区旋转流场的速度相比非旋转流场的速度较小,刀翼内锥区旋转流场的速度相比非旋转流场的速度较大。

During the drilling process,when the local layer is soft and contains a large amount of substances with high viscosity,if the cuttings cannot be discharged in time,mud packs are easily generated,thereby reducing the drilling speed of the drill.The numerical simulation of the rotating flow field and non-rotating flow field of PDC bit was carried out,and the migration of cuttings at the bottom of the well was simulated by DPM technology.The research shows that the migration trajectory of cuttings is significantly different between the rotating flow field and the non-rotating flow ring.The rotating flow field debris erodes the blade back more while the non-rotating flow field debris erodes more on tooth surfaces.The velocity of the rotating flow field in the crown region of the blade is smaller than that of the non-rotating flow field and the velocity of the rotating flow field in the inner cone of the blade is larger than that of the non-rotating flow field.