A Method of Vibration Measurement with the Triboelectric Sensor during Geo-Energy Drilling

In the process of geo-energy drilling, the real-time vibration measurement of drill pipes is of significance for an understanding of the downhole conditions and the properties of rock. However, the vibration sensors used in downhole areas at present require additional power sources, such as batteries, and replacing the batteries would significantly reduce production efficiency and increase costs. In our work, a new vibration measurement method using a triboelectric nanogenerator is proposed which will synchronously achieve axial and lateral vibration, and also simultaneously be self-powered. The triboelectric nanogenerator is mainly made of nanomaterials, such as polyimide film and polytetrafluoroethylene (PTFE), and depends on the pulse signal generated by the contact of the two friction layers to measure the vibration frequency. Axial vibration tests show that the output voltage signal amplitude is approximately 3 V, the measurement range is from 0 to 9 Hz, the measurement error is less than 4%, and the maximum output power is 5.63 uW. Additionally, the lateral vibration tests show that the output voltage signal amplitude is approximately 2.5 V, the measurement range is from 0 to 6.8 Hz, the measurement error is less than 6%, and the maximum output power is 4.01 uW. The nanogenerator can typically work in an environment where the temperature is less than 145 °C and the relative humidity is less than 90%.