Calculation of the flow characteristics of the heat carrier in the well considering the flow modes
Currently, the problem of depletion of easily recoverable oil reserves is urgent. Such a problem can be solved by involving in the development of fields with hard-to-recover reserves, which include high-viscosity oils. For the development of such deposits, thermal enhanced oil recovery methods are used to reduce the viscosity of oil, increase the inflow into producers. Among such methods, the cyclic steam stimulation is fully used the injected heat into the reservoir. One of the main problems of this method is the need to supply steam to the bottom of the well. This problem is relevant, since production with high water cut is formed in a number of fields as a result of cyclic steam stimulation, which indicates steam condensation even in the borehole. The article describes the construction of a physical and mathematical model of the injection of a heat carrier (steam - water) into the reservoir, considering the movement of it along the wellbore, heat loss through the walls of the well and flow modes for the first time. The aim of the work is to determine the influence of technological parameters on the characteristics of the heat carrier in the well, considering the flow modes. The mathematical model developed in the article is based on the laws of conservation of mass, momentum and energy, the friction pressure losses are calculated using empirical formulas for various flow regimes. The distribution of steam quality over the depth of the well, the influence of technological parameters on the wellhead (steam quality, pressure, heat carrier flow rate at the wellhead and thermal conductivity of thermal insulation) on the parameters of the coolant at the bottom of the well (steam condensation depth and heat carrier flow rate at the bottom) are obtained and analyzed. It is shown that with an increase in the thermal conductivity coefficient of thermal insulation, steam condenses higher along the borehole. It is determined that the higher the flow rate of the heat coolant at the wellhead, the deeper the steam penetrates through the well.