PROJECT TITLE :

Electroacoustic Process Study of Plasma Sparker Under Different Water Depth

ABSTRACT:

The plasma sparker has been applied in oceanic high-resolution seismic exploration for decades. Normally it is towed on the water surface. This can be suitable for shallow water, but if the water depth is nice, the resolution will decrease dramatically, particularly within the horizontal direction. This paper proposes the concept of a deep-towed plasma sparker and presents an experimental study of plasma sparker performance in terms of electrical parameters, bubble behavior, and acoustic characteristics. The results show that hydrostatic pressure at a supply depth starting from 1 to 2000 m features a negligible influence on the electric parameters however a sturdy influence on bubble behavior, whereby both the maximum bubble radius and oscillation amount are decreased. The collapse pulse vanishes when the source depth reaches a thousand m or deeper, and no bubble oscillation will be distinguished. The supply level (evaluated by the growth pulse) is additionally decreased because the source depth increases; moreover, the greater the discharge energy, the smaller the source level loss. The discharge energy per electrode ought to be bigger than 20 J for the deep-towed plasma sparker, that can make the supply level loss induced by hydrostatic pressure smaller than the transmission loss. The fast Fourier rework (FFT) results show that the dominant energy is around 20 kHz, which is especially induced by the expansion pulse and its oscillation. According to the simulation results, the fundamental frequency of the acoustic waveform will increase with supply depth in accord with a log linear trend, and additionally reaches tens of kilohertz in deep water. So, before the event of deep-towed plasma sparker, a brand new technical resolution can would like to be developed to resolve this drawback.