同频异位式复合冲击器的研究开发与现场试验

Development and Field Test of the Same-Frequency Different-Phase Compound Impact Tool

为了提高PDC钻头在硬地层中的破岩效率,增加切削齿吃深,同时消除井底钻头的“黏滑”现象,研制出同频异位式复合冲击器。该复合冲击器具有轴向冲击和扭向冲击2种功能,且2种冲击频率相同、但相位不同。基于同频异位式复合冲击器的结构特点和工作原理,确定了轴扭冲击相位角θ2为20°,建立了PDC切削齿轴向冲击力和扭向冲击力的数学模型,明确工具扭冲系统与轴冲系统消耗水力能量比值的合适范围为2.0~3.0。现场试验结果表明,带有复合冲击器钻进时,井底钻柱扭矩平稳,与邻井扭力冲击器+PDC钻头的钻具组合相比,其进尺和机械钻速分别提高111.36%和46.83%,节省1趟钻,且出井PDC钻头复合片磨损轻微。该工具使用效果良好,可为复杂难钻地层提速增效提供一种有效手段。

A same-frequency different-phase compound impact tool was developed to improve the rock-breaking efficiency of PDC bits in hard formations,increase the penetration depth of cutters,and eliminate the“stick-slip”phenomenon of the downhole bit.The compound impact tool has two functions:axial impact and torsional impact,which have the same frequency but different phases.Based on the structural features and working principles of the compound impact tool,the phase angle of axial/torsional impactθ2 is determined to be 20°.The mathematical model of the axial and torsional impact forces of the PDC cutter was established,and the suitable range of hydraulic energy consumption ratio of the torsional impact system and axial impact system was determined to be 2.0~3.0.The field test results show that,when drilling with the compound impact tool,the drill string torque is stable.Compared to the BHA with a torsional impact tool and PDC bit used in the adjacent well,the BHA with the compound impact tool demonstrates the drilling footage and rate of penetration rate(ROP)increased by 111.36%and 46.83%,respectively,corresponding to a reduction of one stripping.Moreover,the PDC bit is found with slight wear after tripping out.The compound impact tool presents a good performance and provides an effective tool for enhancing ROP and drilling efficiency in complex and hard-to-drill formations.