PDC钻头在砾岩层中的磨损规律研究

针对PDC钻头在钻进致密砾岩层中磨损严重的问题,建立了双切削齿PDC钻头简化模型,采用Archard磨损模型并通过有限元软件对PDC钻头切削齿的破岩过程进行模拟,研究了PDC钻头切削齿的后倾角、温度、线速度和钻压对切削齿磨损量的影响规律。研究结果表明:切削齿磨损量在后倾角为15°~20°之间时增长速度平缓,在20°时达到最大值;切削齿磨损量在温度达到300℃后增长速度迅速加快;线速度和钻压与钻头切削齿的磨损量成正比关系。最后采用正交试验法进行敏感度分析,发现对钻头磨损量影响程度由大到小依次为线速度、切削齿后倾角、温度和钻压。该研究对PDC钻头在砾岩层中钻进时合理调节钻井参数以及延长钻头使用寿命具有一定的指导意义。

Study on the Wear Law of PDC Bits in Conglomerate

A simplified model of dual-cutter PDC bits was established to model how the PDC bit is being worn when drilling into dense conglomerate. Then the rock breaking process was investigated using an Archard wear model and finite element software,and how the backward inclination,temperature,linear speed and WOB of the PDC bit influence the bit wear was analyzed. The results show that,the wear rate of cutter increases slowly when the backward inclination is between 15° and 20°,and reaches the maximum value at 20°;the wear rate increases rapidly after the temperature reaches 300 ℃;the linear speed and the WOB are proportional to the wear. Finally,sensitivity analysis by orthogonal tests shows that the influence on the bit wear is linear speed,backward inclination,temperature,and WOB in turn. This study is helpful to how to update drilling parameters and extend the service life of a PDC bit when drilling conglomerate layers.