Panevnyk D. Improving the efficiency of using above-bit jet pumps

The dissertation is devoted to the problem of modeling and improvement of hydraulic connections of elements of the ejection system intended for drilling wells. The dissertation developed a mathematical model of velocity distribution in the mixing chamber of the jet pump in the form of a sliding flow with a potential core limited area with a uniform velocity profile. The adopted model provides for a variable structure of mixed flows: three-layer for subcritical and two-layer for closed distances between the working nozzle and the mixing chamber. Using updated equations of jet pump characteristics scientific-methodical bases of selection of area of existence of dimensionless geometrical and mode parameters at which limit energy indices of well ejection system are achieved are improved. In the process of experimental studies, the dependence of the hydraulic resistance of the element placed on the mixed stream section on the flow rate of the working stream and its invariability with respect to the flow rate of the injected stream was established. In the future, this made it possible to clarify the structure of the equations of the characteristics of the hydraulic system of the jet pump. For the first time, the relationship between the hydrodynamic and strength characteristics of individual elements of the downhole jet pump was established, which made it possible to formulate principles for estimating the stress state of components of the ejection system. An ejection system is proposed by improving hydraulic connections, which allows increasing the mechanical drilling speed by 24.4%, and the passage on the bit - by 27.6%.