The boundaries illustrated by these Assessment Units are the result of geologic studies conducted by the World Petroleum Resources Project, 2009-2011 (Project). The boundaries were used to assess the oil and gas resources within the unit. An assessment unit, as defined by the Project, is a mapped volume of rock within the Total Petroleum System (TPS), sufficiently homogeneous in terms of geology, exploration strategy and risk characteristics to constitute a single population of discovered and undiscovered fields with respect to criteria used for resource assessment. Relatedly, the TPS is the essential elements and processes, as well as all genetically related hydrocarbons that occur in petroleum shows, seeps and accumulations (discovered and undiscovered), whose source is a pod or closely related pods of active source rock.