The gas drift velocity in an elongated bubble can be measured as the bubble velocity moving through stagnant liquid in a pipe. In this study, Computational Fluid Dynamics (CFD) is used to numerically simulate the motion of elongated gas bubbles into liquidfilled channels and pipes. The steady, inviscid flow CFD solution agrees with the analytical solution. Furthermore, the CFD solution for viscous flow agrees with new experimental data. Two flow regimes were predicted by the viscous flow simulations: one of constant bubble velocity and another with decreasing bubble velocity over time. A change in flow regime is observed both in terms of the bubble shape and the gas drift velocity. Correlations are derived from the CFD results that describe the time dependent drift velocity as a function of the liquid viscosity.