Two categories of ﬁelds can be deﬁned for the application of ﬂow modeling workﬂows: green ﬁelds, and brown ﬁelds. In its most fundamental form, a green ﬁeld is an undeveloped ﬁeld, while a brown ﬁeld is a de- veloped ﬁeld. The main difference between a green ﬁeld and a brown ﬁeld is the availability of applicable his- torical production and/or injection data for the brown ﬁeld. This difference has a signiﬁcant impact on reservoir ﬂow modeling workﬂows. A workﬂow for green ﬁelds is presented in this paper, and workﬂows for brown ﬁelds are presented in the companion paper .