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

Abstract

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-Thomsoneffect. 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.

Study on Hydrothermal Cracking of Heavy Oil under the Coexisting Conditions of Supercritical Water and Non-condensate Gas

“…The boundary between the supersaturated water region and the superheated steam region is the saturation line (red line), which begins at the triple point (0 °C and 0.101 MPa) and ends at the critical point (371.15 °C and 22.12 MPa). When the temperature and pressure exceed the critical point, water will be in a supercritical state. − Under supercritical conditions, the unique hydrogen bonds of water are almost completely destroyed (as shown in Figure ), resulting in a very low polarity of SCW. , It can easily dissolve in organic liquids, allowing reactions to occur in a homogeneous phase. − Due to its high density, low viscosity, and good solubility in heavy oil, SCW has been widely studied as a potential heavy oil recovery method. In particular, research has been conducted on the effective use of heavy oil, thermal cracking for upgrading, and synergies with other technologies. − For example, Morimoto et al found that under the solvent effect of SCW, the formation of coke during heavy oil production was effectively inhibited.…”

Production Step-Up of an Oil Well through Nodal Analysis

“…Petroleum production engineering is a part of petroleum engineering that attempts to maximize and optimize oil and gas production in a cost-e ective manner [1][2][3][4][5]. Every producing well is drilled and completed in order to move the oil and/or gas from the reservoir (which is their natural location) up to the surface into stock tanks or sales lines [6][7][8][9][10]. But during this particular phase of oil and gas production, several problems which tend to decrease the amount of produced hydrocarbons may occur.…”