This project has two general objectives. The first objective is to compare the effectiveness of gels in fluid diversion with those of other types of processes. Several different types of fluid-diversion processes are being compared, including those using gels, foams, emulsions, and particulates. The ultimate goals of these comparisons are to (1) establish which of these processes is most effective in a given application and (2) determine whether aspects of one process can be combined with those of other processes to improve performance. Analyses are being performed to assess where the various diverting agents will be most effective (e.g., in fractured vs. unfractured wells, in deep vs. near-wellbore applications, in reservoirs with vs. without crossflow, or in injection wells vs. production wells). Experiments are being performed to verify which materials are the most effective in entering and blocking high-permeability zones. Another objective of the project is to identify the mechanisms by which materials (particularly gels) selectively reduce permeability to water more than to oil. In addition to establishing why this occurs, this research attempts to identify materials and conditions that maximize this disproportionate permeability reduction.