Wellbore flow and heat transfer during formation supercritical CO2 invasion

作者：Dou Liang Bin; Li Gen Sheng^*; Shen Zhong Hou; Huang Zhong Wei; Bi Gang; Wang Hai Zhu

来源：Journal of Engineering Thermophysics, 2013, 34(11): 2086-2092.

• Bottom-hole temperatures
• Formation fluids
• Oil and gas reservoir
• Phase transition point
• Pressure and temperature
• Supercritical CO
• Wellbore
• Wellbore pressure

With the development of oil and gas reservoirs exploration, an increasing number of carbon dioxide (CO2) gas reservoirs, especially those containing high content of CO2 are developed in the world. Considering the pressure and temperature sensitivity of CO2, there is a big error if the phase transition and heat transfer are neglected in the drilling process, and the kick or blowout is easy to occur. Considering the physical properties of CO2 and its phase transition in wellbore, a mathematical model for wellbore flow and heat transfer during formation supercritical CO2 (SC-CO2) invasion was established. Heat transfer and pressure was coupling calculated along with CO2 physical properties parameters in the paper. The results indicate that CO2 transforms from supercritical or liquid to gas state during its rising in the annulus, and the flow above the phase transition point is two-phase flow and the pressure gradient is small in the annulus, while the flow below the phase transition point is single-phase flow and the pressure gradient is large in the annulus. The distributions of pressure and temperature are both influenced by SC-CO2 invasion, the bottom-hole temperature increases with the increase of SC-CO2 influx rate, but the annular wellhead temperature is little impacted by SC-CO2 invasion; the bottom-hole pressure first decreases rapidly, and then increases as SC-CO2 influx rate increases. The backpressure greatly affects the bottom-hole pressure, but the amplitude of affecting diminishes as the backpressure increases.

• 出版日期2013
• 单位中国石油大学（华东）