Fedun V. Excitation by plasma formations of hydroacoustic waveguides

The purpose of the study - establishing mechanisms and patterns of formation and the interaction of high-power pulsed plasma streams with fluid, excitation of elastic waves by plasma streams and their propagation in the waveguide and the influence of these waves on hydrocarbon production processes. The object of the research the physical processes and phenomena that occur during the formation of high-power plasma streams and the generation of acoustic fields caused by the interaction of these f streams with a liquid. The subject of research is the physical characteristics of plasma and the parameters of elastic waves in a hydroacoustic waveguide, as well as the results of the interaction of elastic pulses with oil-bearing rocks. In the work the new design of pulse electrothermic accelerator that maximizes energy transfer from the capacitive storage to the plasma formation. The optimization of configuration of structural elements of accelerator allows to control its amplitude-time characteristics. A method of switching of current-impulse circuits using a magnetic key is developed. It was found by experiment and analytically, that the accelerator generates a plasma having a temperature in the range of 1-1.5 eV at a pressure that reaches a hundred atmospheres. It was shown that the generation of plasma-forming gas in the accelerator is mainly due to ablation of the material of the capillary wall. It is shown that there is a critical value of the energy introduced through the discharge channel to the gas-vapor cavity, above which the solitary elastic pulse is always excited in the waveguide and the cavity expansion is piston-driven. The mathematical model of the plasma accelerator generating hydroacoustic impulses in a fluid medium with cylindrical geometry is developed and the parameters of emitted impulses are investigated. A method for calculating the solitary elastic pulse attenuation in hydroacoustic waveguides (wells up to 4200 meters deep) has been proposed and experimentally tested. The technique and equipment for generation of acoustic fields employing the plasma accelerator are developed. Their use allowed to increase the productivity of oil wells up to 50 times. The results of the dissertation can be used in studies of the interaction of plasma flows with condensed media, the development of pulsed high-current high-voltage devices, geophysical studies, as well as to improve the filtration properties of productive layers.