“…Procedures of this type entail the application of optimal control theory and have their roots in the calculus of variations [6,35]. Adjoint-based optimization techniques have been used in a reservoir simulation setting both for history matching (see, e.g., [8,10,23,31,34]) and for production optimization. Much of the early work on their use for optimization of oil recovery was performed by Ramirez and coworkers, who considered the optimization of several different enhanced oil recovery (EOR) processes [25,26,32].…”