Biot's equations are a popular model for geomechanical simulations of fluid flow in elastic porous media. These simulations are run on a very large scale, resulting in a large number of unknowns. Further complicating matters is that the domains have complex geometry and a vast range of material parameters. The linear systems that arise after discretization of Biot's equations are large enough that iterative methods are preferred. They are also badly conditioned, making effective preconditioners essential. In this work we investigate the effectiveness of several different preconditioners over a wide range of material parameters.