双动力随钻扩眼工艺提速特性分析

Characteristic Analysis on ROP Raising of Bi-energy Reaming While Drilling

常规随钻扩眼工艺只能进行井眼简单扩大作业,功能单一,效率较低。因此,提出了一种双动力随钻扩眼方法,即扩眼钻头与领眼钻头分别由2个动力源驱动破岩,且缩小2个钻头间距。该方法既能用于扩眼作业,又能提高设计井眼钻速。根据提速机理,采用数值模拟方法分析钻压、转速和工具结构尺寸等钻井参数对机械钻速的影响规律。研究结果表明:双动力随钻扩眼工艺卸载岩石内应力效果明显,能在更短时间内使岩石达到损伤破坏;扩眼钻速随钻压增加逐渐减小,随领眼钻头转速的增加而增大,随钻头高度差的增加先增大后减小,随钻头直径比的增大而增大。研究结果可为双动力随钻扩眼装置的优化设计及参数优选提供重要依据。

Conventional reaming while drilling can only perform the simple function of hole expansion with low efficiency. In order to solve this problem, a bi-energy reaming while drilling method is proposed, that is, reaming bit and pilot bit are driven respectively by two power sources to perform rock breaking and reduce the spacing. It can be used for reaming operation and improvement of designed penetration rate. Based on ROP raising mechanism, the numerical simulation method is used to analyze the influencing pattern of WOB, rotating speed, tool structure dimensions and other drilling parameters on the ROP. Research results show that, the bi-energy reaming while drilling can significantly reduce internal stress of rocks and make rocks reach damage failure within a shorter time; reaming ROP can gradually decline with WOB increase, rise with increase of pilot bit speed, rise and then decline with increase of bit height difference, and rise with increase of bit diameter ratio. The results can provide an important basis for optimization design and parameter selection of the bi-energy reaming while drilling device.