水平井PDC钻头黏滑振动规律试验研究

Test on Stick-Slip Vibration of PDC Bit in Horizontal Wells

黏滑振动会造成PDC钻头损伤和井下仪器失效,试验是研究水平井钻柱系统黏滑振动的常用手段。设计了一种微型PDC钻头,基于水平井试验台架进行破岩试验,分析了钻进砂岩和灰岩时钻头端黏滑振动的影响规律。试验结果显示:在相同的进尺和转速下,钻进灰岩时所需的钻压和扭矩比钻进砂岩时所需的钻压和扭矩大约5倍;在0.36 m/h的进尺和15 r/min的转速下,钻进灰岩的黏滑振动强度和黏滑振动倍率是钻进砂岩的5倍,随着转速提高到39 r/min,钻进灰岩的黏滑振动强度和黏滑振动倍率是钻进砂岩的3倍;当转速在30 r/min,随着钻速从0.05 mm/s增加到0.25 mm/s,钻进灰岩的黏滑振动强度增加到了原来的7倍,黏滑振动倍率增加到原来的约9倍,钻进砂岩的黏滑振动强度增加到了原来的约2倍,黏滑振动倍率增加到原来的约1.5倍。试验结果帮助了解钻进不同岩石时的黏滑振动现象,可为今后钻进不同岩石时减轻黏滑振动对井下工具的损伤提供依据。

Stick-slip vibration can lead to PDC bit damage and downhole instrument failure,while testing is a method commonly used to study the stick-slip vibration of drill string system in horizontal wells.In the paper,a micro PDC bit was designed to conduct rock breaking tests on a horizontal well test bench,and the stick-slip vibration influence law at the bit during drilling sandstone and limestone was analyzed.The test results show that at the same footage and rotational speed,the WOB and torque required for drilling limestone are approximately 5 times higher than those required for drilling sandstone;at a footage of 0.36 m/h and a rotational speed of 15 r/min,the stick-slip vibration intensity and stick-slip vibration rate of drilling limestone are 5 times higher than those of drilling sandstone;as the rotational speed increases to 39 r/min,the stick-slip vibration intensity and stick-slip vibration rate of drilling limestone are 3 times higher than those of drilling sandstone;when the rotational speed is 30 r/min,as the ROP increases from 0.05 mm/s to 0.25 mm/s,the stick-slip vibration intensity of drilling limestone increases to 7 times the original,the stick-slip vibration rate increases to about 9 times the original,the stick-slip vibration intensity of drilling sandstone increases to about 2 times the original,and the stick-slip vibration rate increases to about 1.5 times the original.The test results help to understand the phenomenon of stick-slip vibration when drilling different rocks,providing a foundation for reducing the damage of stick-slip vibration to downhole tools when drilling different rocks in the future.