Phenomenological model of an open-type geothermal system on the basis of oil-and-gas well

Abstract

This paper relates to mining-well technologies. A theoretical and methodological approach is proposed to modeling geothermal well systems, which includes the development of: principal technological scheme of a geothermal system; schemes of transformation and movement of energy and a heat-transfer medium; the geothermal system phenomenological model; analysis of subprocesses and obtaining their mathematical models and, on this basis, the mathematical model of the geothermal model as a whole. An example of an advanced open-type geothermal well system is studied, which is based on the oil-and-gas well with one loop of circulation and the parallel connection of heat pumps at characteristic points of the system. The subprocesses of the developed phenomenological model are analysed and the characteristic features of their mathematical description are revealed; in particular, it is substantiated that the redistribution of heat power entering from a fluid-saturated bed is substantially dependent on the lateral wellbore geometry. Another important feature is to model the downhole heat pump and the modes in the scheme as a whole, which is based on the mass flow rate of a heat-transfer medium in its circulation loop. A generalized formula is presented for the heat power of the analysed advanced geothermal well system.