Methods for injecting a fluid into a subsurface formation are provided. Each of the methods includes the obtaining data, including formation parameters and operational variables, related to an injection well. A regime of operation for the injection well is determined. The regime of operation is determined using a heuristic model. In one aspect, one or more operational variables, including completion design, reservoir development procedures, and/or injection procedures, is designed based at least in part on the determined regime of operation. Water or other fluid may then be injected into the subsurface formation. The step of determining the regime of operation for the injection well may use a full physics computational simulation to construct a mathematical model that can estimate the operating regime for the water injection well. Alternatively or in addition, field data may be used.