摘要
过激的振动频率将损坏钻具、影响效率、甚至造成井下事故,因此有必要对井下钻具的振动频率进行实时测量。本文基于摩擦纳米发电机提出了一种耐高温的井下振动传感器,该传感器不仅具有振动测量功能,也具有发电功能。当该传感器测量振动频率时,试验显示其测量范围为0~8 Hz,测量误差<4%,信噪比高,抗干扰能力强,且输出信号幅值与传感器和振动源的距离成反比。当该传感器用于发电时,试验显示振动频率越高其发电量越大,其在8 Hz工况下的输出电压、输出电流和输出功率分别为70 V、12 ×1
钻探是固体矿产及深部能源勘探开发等的重要技术手段,在钻进过程中,井下钻具组合受多种激励作用而发生振动,包括轴向振动、横向振动及扭转振动。过激的振动将损坏钻具、影响效率、甚至造成井下事故,因此有必要对井下钻具的振动情况进行实时测
国内外学者在钻柱振动测量方面取得了一些成果,譬如Kim
综上可见,目前现有的振动测量方法可满足多数的井下测量需求,但对于高温井或深井而言,现阶段多采取隔热装置减缓热传播速度来满足常温传感器在高温井下的使用,但当工作时间较长时,现有的隔热装置亦无法发挥作用,因此,能够耐高温的振动传感器无疑将更加适宜实际工况。与此同时,井下传感器或仪器的供电方式也是随钻测量领域的痛点之一,而摩擦纳米发电机技术为解决耐高温传感器及供电问题带来了曙光。
摩擦纳米发电机来源于纳米材料的摩擦起电和静电感应现象,在分布式发电及传感器领域得到了广泛的应
在工作温度方面,由于温度梯度的存在,井下温度会随着钻进深度的增加而升高,因此将工作温度设置为大于175 ℃以满足一般高温井的需求。对于工作湿度,由于传感器必须密封在单独设计的测量仪器中使用,而密闭的测量短节内空气湿度较低,因此传感器对空气湿度没有具体要求,但湿度适应范围越宽越好。对于输出信号幅值,根据晶体管-晶体管逻辑(TTL-transistor Logic)输入高电平的检测标准,输出电压幅值应大于2 V。目前井下低功耗供电仪器的功率约mW级别,因此传感器具备为其他随钻测量低功率仪器供电的潜力,以期将来解决井下供电问题,即传感器具有发电功能,因此输出功率越多越好。此外,传感器的设计尺寸应尽可能小,以尽可能满足小尺寸钻探需求。根据以上详细介绍,设计指标如
由于实际使用时传感器是安装于特殊设计的密封短节内,因此传感器设计时仅需进行简单密封即可。如

图1 传感器结构组成
Fig.1 Sensor components
传感器通过支撑台固定在测量短节内,当发生轴向振动时,活动球相对于固定球上下运动,并由于摩擦起电和静电感应产生同频率的摩擦电信号,随后便可通过统计摩擦电信号的振动频率,以实现对井底钻具振动频率的测量。

图2 传感器工作原理示意
Fig.2 Working principle of the sensor
当传感器至少工作一次时,由于摩擦起电作用,可对活动球进行预充电,
试验测试分为3部分,一是测量振动频率的传感测试,二是测量振动发电性能,三是测量对环境的适应性。测试平台的搭建如

图3 测试设备
Fig.3 Test devices
通过对传感器的传感特性进行测试,得到以下结论。
(1)如

图4 传感性能测试结果
Fig.4 Performance test results of the sensor
(2)如
(3)
该传感器利用摩擦起电原理研发,其测量过程也是发电过程,因此可将井下钻具振动能量转化为电能,为此,我们对传感器的发电性能进行了测试。如

图5 传感器发电性能测试结果
Fig.5 Power generation performance test results of the sensor
当用于高温井或深井时,由于地温梯度的存在,井下温度随钻深逐渐增加,为此测试了传感器在高温下的输出性能,结果如

图6 外部环境测试
Fig.6 External environment test
所研制的振动传感器具有振动测量和发电的双重功能,预期将在钻探领域取得以下几方面的应用。一是所研制的传感器具有发电功能,未来可考虑在井下钻具组合不同位置处安装该传感器,从而形成井下分布式的储能,为井下低功耗随钻测量仪器提供间歇式或实时供电;二是所研制的传感器为自供电式的振动传感器,当环境温度达到180 ℃时仍可正常工作,且工作温度范围还具有进一步提升的空间,因此未来可用于高温或超深井下的振动测量;三是基于此原理所研制的传感器除可测量振动外,理论上还可测量转速、压力及流量等参数的测量,因此未来可考虑基于此原理设计完全密封的随钻测量仪器,无需安装任何传感器和电源便可实现随钻测量功能,形成具有自供电及自传感功能的新型随钻测量仪器;四是基于此原理可设计具有自发电功能的智能钻杆,并在智能钻杆上增加信号中继站,利用智能钻杆的自发电为信号中继站供电,从而形成高速的井下信号传输网络。
本研究基于摩擦纳米发电机设计了一种井下耐高温的振动频率传感器,该传感器同时具有振动测量与发电的功能,可在温度<180 ℃及湿度<90%的环境下正常使用,具有较强的环境适应性。当该传感器用于测量振动时,其测量范围为0~8 Hz,测量误差<4%,信噪比高,抗干扰能力强,且输出信号幅值与传感器和振动源的距离成反比。当该传感器用于发电时,其在8 Hz工况下的输出电压、输出电流和输出功率均达到最大值,分别为70 V、12×1
但该传感器仍然存在两点需进一步改进,一是振动频率测量范围较小,无法满足高频振动测量需求。解决该问题的关键是从传感器结构及回复力方式入手,比如可采用磁悬浮方式对活动球进行悬浮以增加回复速度,从而提高频率测量范围。二是若作为发电机使用时电量较小,其发电量无法带动井下使随钻测量仪器工作,因此可从提升摩擦材料发电性能或联合多种井下发电方式,从而提高发电量。
参考文献(References)
Kapitaniak M, Hamaneh V V, Chávez J P, et al. Unveiling complexity of drill‑string vibrations: Experiments and modelling[J]. International Journal of Mechanical Sciences, 2015,101:324-337. [百度学术]
Kim Y Y, Simons L H. Drilling vibration measurements on a BOP stack[C]//Offshore Technology Conference, 1976.doi:10.4043/2620-MS. [百度学术]
刘伟,周英操,王瑛,等.井下振动测量、分析原理研究[J].石油钻采工艺,2012,34(1):14-18. [百度学术]
LIU Wei, ZHOU Yingcao, WANG Ying, et al. Study on downhole vibration measurement and analysis theory[J]. Oil Drilling & Production Technology, 2012,34(1):14-18. [百度学术]
Kalista Karel, Liska Jindrich, Jakl Jan. A vibration sensor‑based method for generating the precise rotor orbit shape with general notch filter method for new rotor seal design testing and diagnostics[J]. Sensors, 2021,21(15):5249. [百度学术]
陈波.井下钻柱振动测试方法研究[D].成都:西南石油大学,2015. [百度学术]
CHEN Bo. Research on downhole drilling string vibration testing method[D]. Chengdu: Southwest Petroleum University, 2015. [百度学术]
Emmanuel Schen, A.D.Snell, B.H.Stanes. Optimization of bit drilling performance using a new small vibration logging tool[C]//SPE/IADC Drilling Conference. Amsterdam: 2005. [百度学术]
翟小强,王瑛,刘伟.存储式井下振动测量工具的设计与室内试验[J].石油钻探技术,2011,39(4):111-114. [百度学术]
ZHAI Xiaoqiang, WANG Ying, LIU Wei. Design and laboratory test of memory downhole vibration measurement tool[J]. Petroleum Drilling Techniques, 2011,39(4):111-114. [百度学术]
吴蔚娓,沈雪峰.存储式井下振动测量仪的应用研究[J].石化技术,2019,26(2):79-80. [百度学术]
WU Weiwei, SHEN Xuefeng. Research on the application of stored underground vibration survey[J]. Petrochemical Industry Technology, 2019,26(2):79-80. [百度学术]
Lines L A, Mauldin C L, Hill J W, et al. Advanced drilling dynamics sensor allows real‑time drilling optimization, damage prevention and condition monitoring of RSS and LWD BHAs[C]//SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers, 2014. doi:10.2118/170586-MS. [百度学术]
Millan E, Ringer M, Boualleg R, et al. Real‑time drillstring vibration characterization using machine learning[C]//SPE/IADC International Drilling Conference and Exhibition. Society of Petroleum Engineers, 2019. doi:10.2118/194061-MS. [百度学术]
Fan F R, Tian Z Q, Wang Z L. Flexible triboelectric nanogenerator[J]. Nano Energy, 2012,1(2):328-334. [百度学术]
Qin K, Chen C, Pu X, et al. Magnetic array assisted triboelectric nanogenerator sensor for real‑time gesture interaction[J]. Nano‑micro Letters, 2021,13(1):1-9. [百度学术]
Vivekananthan V, Chandrasekhar A, Alluri N R, et al. A highly reliable, impervious and sustainable triboelectric nanogenerator as a zero‑power consuming active pressure sensor[J]. Nanoscale Advances, 2020,2(2):746-754. [百度学术]
Liu C, Wang Y, Zhang N, et al. A self‑powered and high sensitivity acceleration sensor with VQa model based on triboelectric nanogenerators (TENGs)[J]. Nano Energy, 2020,67:104228. [百度学术]
Zhou Q, Huang H, Wu C, et al. A self‑powered sensor for drill pipe capable of monitoring rotation speed and direction based on triboelectric nanogenerator[J]. Review of Scientific Instruments, 2021,92(5):055006. [百度学术]
吴川,杨朔,樊辰星,等.具有井下自发电及自传感功能的随钻测量新方法研究——以用于振动测量的井下摩擦纳米发电机为例[J].钻探工程,2021,48(4):47-53. [百度学术]
WU Chuan, YANG Shuo, FAN Chenxing, et al. Research on a new measurement while drilling method with downhole self‑powered and self‑sensing function—An example of triboelectric nanogenerator used in downhole vibration measurement[J]. Drilling Engineering, 2021,48(4):47-53. [百度学术]
Yi F, Zhang Z, Kang Z, et al. Recent advances in triboelectric nanogenerator-based health monitoring[J]. Advanced Functional Materials, 2019,29(41):1808849. [百度学术]
Wang S, Tai H, Liu B, et al. A facile respiration‑driven triboelectric nanogenerator for multifunctional respiratory monitoring[J]. Nano Energy, 2019,58:312-321. [百度学术]
Luo J, Gao W, Wang Z L. The triboelectric nanogenerator as an innovative technology toward intelligent sports[J]. Advanced Materials, 2021,33(17):2004178. [百度学术]
Zhang D, Shi J, Si Y, et al. Multi‑grating triboelectric nanogenerator for harvesting low‑frequency ocean wave energy[J]. Nano Energy, 2019,61:132-140. [百度学术]
Lin Z, Zhang B, Guo H, et al. Super‑robust and frequency‑multiplied triboelectric nanogenerator for efficient harvesting water and wind energy[J]. Nano Energy, 2019,64:103908. [百度学术]
Rahman M T, Rana S M S, Salauddin M, et al. A highly miniaturized freestanding kinetic‑impact‑based non‑resonant hybridized electromagnetic‑triboelectric nanogenerator for human induced vibrations harvesting[J]. Applied Energy, 2020,279:115799. [百度学术]
Zhang Q, Jiang C, Li X, et al. Highly efficient raindrop energy‑based triboelectric nanogenerator for self‑powered intelligent greenhouse[J]. ACS Nano, 2021. [百度学术]
Xiong J, Cui P, Chen X, et al. Skin‑touch‑actuated textile‑based triboelectric nanogenerator with black phosphorus for durable biomechanical energy harvesting[J]. Nature Communications, 2018,9(1):1-9. [百度学术]
Wu C, Huang H, Li R, et al. Research on the potential of spherical triboelectric nanogenerator for collecting vibration energy and measuring vibration[J]. Sensors, 2020,20(4):1063. [百度学术]
Wu Chuan, Zhou Qing, Wen Guojun. Research on self‑powered rotation speed sensor for drill pipe based on triboelectric‑electromagnetic hybrid nanogenerator[J]. Sensors and Actuators A: Physical, 2021,326: 112723. [百度学术]