Mathematical Modeling of the Hot Steam-Water Mixture Flow in an Injection Well

摘要

In this paper, for the problem of pumping heat-transfer agent into an oil reservoir, a mathematical model of the processes occurring during the movement of a hot steam-water mixture in an injection well has been proposed. This model takes into account phase transitions occurring in a two-phase mixture "water-steam", and external heat exchange of the well with surrounding rock (including permafrost). Algorithm has been constructed that allows calculating for different time moments of the well operation: the heat-transfer agent parameters, the temperature distribution in the surrounding rock and the thawing radius of permafrost along the depth of the injection well. According to the proposed algorithm, a computer code was developed and numerical experiments were carried out to find the parameters of the downward flow of a hot steam-water mixture in an injection well. By calculation it is shown that using of heat-insulated pipes leads to a lesser heat loses of a heat-transfer agent along the depth of an injection well. Also, using of heat-isolating materials on the outer surface of the well lifting column allows to increase the depth and quantity of steam (compared with non-heat-insulated lifting column). It is shown that with an increase in the heat insulating layer, the thawing radius of permafrost decreases, which is caused by a decrease in heat transfer from the well product to surrounding rocks.