Resource plays present unique challenges. These large, continuous accumulations need to be assessed by mapping out variations in risks and prospectivity that divide the resource play fairway into discrete, contiguous segments. For resources such as shale gas, shale oil, and coal-bed methane, the challenge is economic recovery. The assessment challenge is the same: Modeling how the resource play should be explored and exploited. Given the current focus on liquid hydrocarbons, the challenge for shale-based resource plays is assessing the potential for oil in rocks that typically hold both gas and oil. This paper extends earlier work by applying an activity-based model to the exploration and exploitation of a shale play. The model segments the play into three types of areas: shale oil, shale gas, and transition areas with uncertain proportions of both shale oil and shale gas. The assessment model also promotes understanding of both the areas and the relative impact of alternative completion solutions. The model generates stochastic performance metrics that capture alternative outcome scenarios, economic returns, and the production and reserve delivery schedule. The performance metrics support both project- and portfolio-level decisions regarding resource plays. Project-level application is illustrated using data from an Eagle Ford– type resource play.