A Comprehensive Model for Simulating Supercritical-Water Flow in a Vertical Heavy-Oil Well

Summary Supercritical water has been proved effective in heavy-oil recovery. However, understanding the flow characteristics of supercritical water in the wellbore is still in the early stages. In this paper, using the theory of heat transfer and fluid mechanics and combining that with the physical properties of supercritical water, a heat-transfer model for vertical wellbore injection with supercritical water is established. The influence of heat transfer and the Joule-Thomson effect on the temperature of supercritical water are considered. Results show the following: The predicted values of pressure and temperature are in good agreement with the test values. The apparent pressure of supercritical water at the upper end of the wellbore is lower than the apparent pressure at the lower end. However, the equivalent pressure of supercritical water at the upper end of the wellbore is higher than the equivalent pressure at the lower end. The apparent pressure of supercritical water is affected by three factors: flow direction, overlying pressure, and Joule-Thomson effect. The closer to the bottom of the well, the greater the overlying pressure of the supercritical water, resulting in an increase in apparent pressure and the density of the supercritical water. As the injection time for supercritical water increases, the temperature around the upper horizontal wellbore increases.