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Документ Improving the geometric topology of geothermal heat exchangers in oil bore-holes(2019) Fyk, M. I.; Biletskyi, V. S.; Ryshchenko, Ihor; Abbood, MohammedA review has been conducted of key trends in the development of geometric topology of geothermal heat exchangers. Authors proposed approaches to improving the designs and network structures for heattransfer media circulation in the bottom-hole space of oil-and-gas reservoirs. Four geometric topologies of geothermal heat exchangers have been analysed: І – ІІ – rectilinear vertical smooth and finned pipelines; ІІІ – IV – a cluster in the form of a set of smooth and finned single-pipe elements, representing a figure of "squirrel wheel" or "meridian sphere" type. It is shown that the most effective technical solution, which ensures the increase in the coefficient of performance (COP) of bore-hole geothermal systems is finning the heat exchanging pipes. For the heat exchangers of І – ІІ type, the calculated increase in COP in comparison with smooth pipes is 40%, and for ІІІ – IV type – 95%. The key parameters influencing the COP of a geothermal heat exchanger are: the radius of fluids draining out during the heat exchange process, the radius of pipelines with circulating heat-transfer medium, the diameter of a cluster heat exchanger, the heat exchange area, the parameters of rocks thermal resistance in the bottom-hole zone of heat-receiving.Документ Modeling of the lifting of a heat transfer agent in a geothermal well of a gas condensate deposit(Національний технічний університет "Дніпровська політехніка", 2020) Fyk, M. I.; Biletskyi, V. S.; Abbood, Mohammed; Al-Sultan, Mohammed; Abbood, Majid; Abdullatif, Haval; Shapchenko, YevhenPurpose is to develop mathematical model of nonisothermal inflow and lifting of the recovered gaseous mixture (i.e. geothermal fluid) of a well taking into consideration dynamic coefficient of heat transfer and thermal diffusion coefficient; fluid expansion coefficient in terms of nonadiabatic process; effect of average integral environmental temperature on the heat transfer coefficient; changes in molar mass of the fluid during the well operation; and a process of the productive seam cooling during initial development stages (i.e. months-years). Methods of material and energy balance of fluid-heat flows within a productive formation and within a well as well as forecasting of geothermal fluid production; numerical methods of fluid thermal gas dynamics; Runge-Kutta 4th order method; and Quazi-Newton method to solve nonlinear equations have been applied. Findings. It has been demonstrated that thermal gradient of rocks and thermal carrier-rock heat exchange vary depending upon operation modes of the formation and the well in terms of temperature effect, temperature difference in humidity, viscosity, compressibility, and other rock characteristics determining efficiency of thermal diffusion as well as coefficient of heat exchange between the fluid and rocks. Originality. The specified equations of thermal energy balance in terms of radial filtration and well product lifting have been developed. The equations are more preferable to compare with the current calculation technique, where a coefficient of fluid is expanded in a seam in the context of nonadiabatic process, and consideration of effect of average integral environment temperature of the heat transfer strength (the known methods takes into account geometric mean of the formation temperature). Actual changes in molar mass of the produced geothermal fluid during the whole period of the well operation (i.e. up to 50 years) are involved. Thermal gas dynamic model well inflow-lifting has been improved owing to the consideration of a transient process of the productive formation cooling during the initial stage of the geothermal fluid production (i.e. months-years). Practical implications. The developed mathematical model helps specify calculation of a well yield by 10-15%. To compare with the standard methods, the model makes it possible to perform 20-30% specification of heat output by a gas condensate well in terms of thermobaric intensification of the fluid production as well as in terms of binary techniques of fluidgeoheat generation.