As we discussed in the System Dynamics and Energy Modeling section, one of the system dynamics analyses conducted in support of the world modeling efforts was a natural gas discovery and production model created by MIT Master's student Roger Naill. Naill based his model on the life cycle theory of oil and gas discovery and production put forth by petroleum geologist M. King Hubbert. Like Hubbert, Naill assumed for his analysis that the total amount of oil and gas in the United States (i.e., the amount of oil and gas "in place"), and hence the "ultimately recoverable" amount of oil and gas in the United States, is finite.

In this chapter, we recreate Naill's original Natural Gas Discovery Model as a case study in how to construct and experiment with system dynamics models. To make the explanation of the model more manageable, we present a series of model versions, each version incrementally more complex with the addition of new structure. In each case, the reader is encouraged to run the model to see how the additional structure affects its behavior. In the final section of this chapter, we present a "flight simulator" version of the completed model. The reader is encouraged to conduct policy experiments by changing decision variables or model uncertainty variables to see how the behavior of the system changes in response.