(n.) Shale Gas. A technique used to represent the history of a sedimentary basin, including the processes and components necessary to form petroleum: a petroleumsource rock, a reservoir, a trapping mechanism, a seal, and the appropriate relative timing of formation of these. Using geologic, geophysical, and engineering data, scientists create a 3D model of the subsurface that can be used to understand whether petroleum is present and how much might exist in potential traps. Petroleum systems models can be used to help predict pore pressure and plan well construction and field development. A useful petroleum systems model can be used to identify and explain inconsistencies in the data. The resulting models are valuable duringexploration for identifying resource richness, such as sweet spots in unconventional plays such as shale gas, and during field development andproduction for improving completion efficiency. Petroleum systemsmodeling is distinct from reservoir simulation in that it covers a larger scalethat might include multiple oil and gas fields and considers a geologic time frame of millions of years rather than a production time frame of years or decades. More Details: Basin and Petroleum System Modeling