A Bio-Inspired Downhole Power Supply using Vibration Energy

Abstract With the rapid development of the petroleum industry, downhole tools in used in are gradually developing from mechanization towards automation and intelligence. Now most of the electrical devices used in the downhole tools utlizize the wellbore control technolgy to work in differenl situation. These devices usually adopt traditional battery technology as the solution of power supply. It is unavoidable to fish up the devices using disposable batteries or to put the charger into the accurate downhole position to charge the rechargeable batteries if the the batteries run out. As a result of these situaion, the normal working process is interrupted, which leads to a significant decline in productivity. Facing the delimma, this paper proposes a bionics piezoelectric energy harvester based on vortex-shedding vibration to solve the existing problem of traditional battery technology in the fluid environment. The harvester mainly consists of bluff body, piezoelectric energy transducer, and the rectifying circuit. PZT and PVDF are used as functioanl materials in the key component of the piezoelectric energy transducer. Finally PZT shows the superior performance than the one of PVDF considering the experimental results about the working condition, service life and awful operating process. Testing results also showed that the voltage of the harvester can achieve 4.88V under the condition of 0.8m/s flow velocity and 25mm pipeline diameter and the power can reach 1600mW when the load resistance is about 360 kΩ. The bionic vibration energy harvester offers an intriguing alternative to collect ambient energy from liquid environment for long-term use of power.