Abstract:

A model based on lattice Boltzmann method (LBM) is developed to solve the heat transfer problems in the wellbore, which can simultaneously solve the controlling equations of temperature-pressure coupled flow of fluid in the wellbore, forced thermal convection in fluid flow and fluid-solid heat exchange between the wellbore and the formation, so it can realize the coupling solution of fluid flow field, fluid temperature field and wellbore temperature field, and compared with the traditional model, it not only overcomes the defect that the velocity is constant in wellbore, but also has a wider scope of application and higher computational efficiency. The reliability and accuracy of the model have been verified by comparative analysis with previous studies. The results show that the change of fluid velocity in the wellbore affects the temperature distribution of the fluid in the wellbore. Under the production condition, the temperature distribution at the center of the fluid is high and the temperature at the boundary of the fluid is low at the same depth. The downward trend of fluid temperature along the shaft axis will go through three stages: slow, steady and slow, and these three stages are affected by flow Reynolds number or fluid Prandtl number.

Key words: wellbore temperature, wellbore pressure, lattice Boltzmann, Prandtl number, coupling simulation