Abstract
Flow diagnostics are simple and controlled numerical flow experiments run to probe a reservoir model, establish connections and basic volume estimates, and measure heterogeneity in flow paths. All these quantities are quick to compute and can thus be used interactively to explore fluid communication in a geological model before or after more comprehensive multiphase flow simulations. This user guide briefly outlines the various types of flow diagnostics and the corresponding graphical user interface (GUI) you can use to postprocess black-oil type multiphase flow simulations. The GUI can be used for multiphase simulations stored in either MRST format or ECLIPSE output format.