Dynamic replication can be used to reduce bandwidth consumption and access latency in high performance "data grids" where users require remote access to files that are large: on average, around two Gigabytes. Different replication strategies are defined depending on when, where, and how the replicas are created and destroyed. We describe a simulation framework that we have developed to enable comparative studies of alternative dynamic replication strategies. We present preliminary results obtained with this simulator, in which we evaluate the performance of five different replication strategies for three different kinds of access patterns. The data in this scenario is read-only and so there are no consistency issues involved. The simulation results show that the best strategies have significant savings in latency and bandwidth if the access patterns contain a small degree of geographical locality.