This presentation focuses on issues, unique to deepwater completions, that impact the selection and appropriate application of completion fluids. Some fluid engineering and selection issues such as density prediction, displacements, and brine composition, considered almost routine when working on shelf wells, are far from routine for deepwater wells. Deepwater environments present the unique combination of high pressure and low temperature. This combination requires chemical solutions for completion fluids specific to this challenging environment. Issues such as pressure-induced crystallization, hydrate control, fluid expansion and compression, thermal insulation, and fluid compatibility are some of the chemical considerations that must be planned for and solutions provided. In addition to the normal completion fluid compatibility issues such as compatibility with crude oil, formation water and formation rock, the various control line fluids, hydrate inhibitors and other production chemicals used in the deepwater wellbores require special considerations.