A compressible two-fluid multiphase model for CO2 leakage through a wellbore

This paper introduces an effectively mesh-independent and computationally efficient model for CO2 leakage through wellbores. A one-dimensional compressible two-fluid domain, representing a homogeneous air gas and a multiphase CO2 with a jump at the interface between them, is modeled. The physical domain is modeled using the drift-flux model, and the governing equations are solved using a mixed finite-element discretization scheme. The standard Galerkin FEM, the partition of unity method, and the level-set method are integrated to solve the problem. All important physical phenomena and processes occurring along the wellbore path, including fluid dynamics, buoyancy, phase change, compressibility, thermal interaction, wall friction, and slip between phases, together with the jump in density and enthalpy between air and CO2, are considered. Two numerical examples illustrating the computational capability and efficiency of the model are presented. Copyright (c) 2015 John Wiley & Sons, Ltd.