An explicit finite difference model for prediction of wellbore pressure and temperature distribution in CO2 geological sequestration

Abstract

AbstractTo conveniently realize the coupling calculation between wellbore pressure and temperature and consider the friction loss in the process of wellbore flow and heat transfer, this work takes the one‐dimensional steady flow with homogeneous fluid in wellbores as the analysis object and divides the wellbore into finite micro‐segments. Then we derive the explicit finite difference model (EFDM) about pressure in a certain micro‐segment of wellbore, based on the mass and momentum equations. Next we deduce the EFDM about temperature reflecting the wellbore heat transfer in the same micro‐segment according to the energy balance equation. After that, a coupling calculation method for the EFDM about pressure and temperature is presented. Finally, a comparison of the simulation results of the EFDM, other models, and the log data from engineering is implemented, which demonstrates that the prediction results of the EFDM are more consistent with the log data than the results of other models. Therefore, the reliability of the EFDM about pressure and temperature and their coupling calculation method is verified. Discussion of the friction loss in the energy balance equation and the isobaric specific heat capacity showed that both have a great impact on wellbore temperature distribution, which means the friction loss should not be ignored and the isobaric specific heat capacity should not be assumed as a constant in applications. Generally, the prediction of wellbore pressure and temperature distribution and the comprehension of the internal essence of wellbore flow and heat transfer will be effectively promoted by this work. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd.