Search Results (2)

The high-power drive of an impulse sound source with drilling makes the system’s life short and difficult to integrate. This report firstly establishes the pulse discharge experimental system and finite element model, and compares and verifies the typical parameters. Second, the study examines how the energy storage capacitor’s charging voltage, discharge electrode gap, and liquid environment conductivity influence the electroacoustic performance of needle series electrodes. Subsequently, the optimal electrode configuration is identified under power constraints, yielding electroacoustic parameters and curves suitable for low-power impulsive sound sources. The findings reveal that the needle–plate electrode outperforms others in pre-breakdown duration, peak impulse wave strength, highest sound pressure level, and electroacoustic conversion efficiency. However, its higher power demand can be mitigated by lowering the charging voltage and narrowing the electrode gap. The charging voltage of the power-limited needle–plate electrode is only 3.5 kV, the impulse wave intensity reaches 1.27 MPa, and the peak system power is effectively controlled within 6.66 kW. A stable 288 dB SPL output is maintained up to 1 kHz, and above 250 dB in the wide bandwidth of 1–100 kHz. Needle–plate electrodes provide broadband excitation and high intensity SPL output despite power limitations. Full article

In acoustic deep detection technology, conventional monopole, dipole, and phased-array sound sources are far inferior to impulsive sound sources in frequency and amplitude. But impulse sound sources mostly work under high-power, high-voltage, and high-current conditions, which are difficult to be applied downhole. The purpose of this paper is to reduce the power of the impulse sound source system and at the same time to stimulate excellent impulse wave characteristics. Firstly, an experimental impulse sound source system using needle-rod electrodes was constructed, and the discharge experimental results were analysed. Secondly, a finite element model of the needle-rod electrodes of the impulse sound source was established based on the experimental conditions, and the effects of the charging voltage, electrode gap, and liquid conductivity on the power and electroacoustic parameters of the needle-rod electrodes system were investigated separately. Finally, the optimised electroacoustic parameters and curves of the needle-rod electrodes of the low-power impulse sound source were obtained. The results show that the charging voltage is the most significant parameter affecting the power of the needle-rod electrode system; a larger liquid conductivity and a suitable electrode gap are required for the optimal impulse wave parameters. The optimised low-power impulse sound source system with needle-bar electrodes with a power of 20.95 kW achieves an impulse wave intensity of 4.78 MPa, with a sound pressure level above 295 dB up to 1 kHz and above 225 dB from 1 kHz to 300 kHz. Optimised needle-rod electrodes for low-power impulse sound sources have the advantages of a wide bandwidth and high energy. This makes the downhole application of low-power impulse sound sources possible, which will play an important role in oil exploration and other drilling exploration fields. Full article