Femiak Y. Theory and practice of using cavitation processes during well drilling

The thesis is devoted to solution of the important scientific and technical problem of intensification of rocks destruction during well drilling due to the effective use of energy of cavitation fluctuations of flushing fluid. The dissertation developed the mechanisms of rocks destruction and the theory of cavitation processes generated on the well hole and solved an important problem of intensifying the destruction of rocks during drilling due to the modernization of the cavitation chambers of the drill bit. Intensification of the destruction process is achieved by transferring the washing regime to the cavitation-pulsation regime, which allows reducing the energy intensity of the rock destruction process and provides for increasing the mechanical speed of drilling and drilling on the bit. It is shown that one of the most promising methods of destruction of rocks is the method of cavitation-pulsating influence on the rock. Realization of such influence is possible during rotary drilling at the expense of transfer of well washing into cavitation mode. It was investigated that due to the use of cavitational pulsation of the flushing fluid during drilling compared to the hydro-monitors of continuous flushing mode, the energy intensity of the rock destruction process is reduced. Analytical dependencies are proposed for prediction of the frequency division of energy, which is released when scaling cavitation bubbles on the well hole. The drilling practice is developed and introduced in the practice of practical calculation of optimization of cavitation-pulsation action on rocks during well drilling, which allows to determine the effective parameters of the drilling process with cavitation-pulsating washer for intensification of the destruction of rocks while maintaining the durability of the tool.