A method can include receiving information that includes data that correspond to a range of a fluid production network variable; based at least in part on a portion of the data, determining optimal parameter values of a multi-parameter proxy model for at least a portion of the range of the fluid production network variable; based at least in part on a portion of the optimal parameter values, deriving functions for the parameters of the multi-parameter proxy model; and based at least in part on the functions, determining a value of the fluid production network variable for a fluid production network.