Transient nitrogen injection in a cylindrical porous cap initially filled with natural gas

In this work, an analysis is done on the sudden injection of gaseous nitrogen in a porous cap filled initially with natural gas. A cylindrical geometry has been selected to derive the mathematical model. The resulting nondimensional governing equations for the pressure of the binary mixture and the corresponding nitrogen concentration are solved numerically using conventional finite difference techniques. The numerical results show that the injection process is sensibly controlled by several nondimensional parameters, which have a clear influence in order to define the corresponding nitrogen distribution throughout the cap.