一种防卡钻头的研究和应用

钻井过程中发生的卡钻事故，卡点多数在钻具串中直径较大、环空间隙较小的位置，特别是在复杂地层的钻井中，钻头位置是存在卡钻风险最大的一个地方。常规的三牙轮钻头在易坍塌地层中使用时卡钻严重。对常规三牙轮钻头进行了分析改进，通过改变喷嘴位置、增大钻头的过流面积、增加钻头的破岩能力3个方面，实现了防卡的功能。柯21-3井的初期应用以及改进后在柯30P井的应用效果表明，改进后的牙轮钻头在易坍塌地层和煤层中防卡效果较好。

Research and application of an anti-stick bit

Sticking point of sticking accident during well drilling process mostly lies in the place where the drilling string has larger diameter, so the annular is smaller. Especially in the drilling of complex formation, the position with the bit is where the pipe sticking most easily happens. The use of conventional three-cone bit in sloughing formation has some problems. Based on the analysis and improvement for conventional three-cone bits, we mainly achieve the function of anti-stick by changing the nozzle position, increasing the bit open area, and increasing bit rock breaking capacity. According to the application on Well K21-3 and Well K30P, the anticipated objective has been realized. The improved cone bit has good effect on sloughing formation and coalbed formation.