USGS National and Global Oil and Gas Assessment Project - Williston Basin, Tyler Formation Assessment Unit Boundaries and Assessment Input Data Forms

This data release contains the boundaries of assessment units and input data for the assessment of undiscovered oil and gas resources in the Tyler formation of the Williston Basin province in Montana, North Dakota and South Dakota. The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the higher-level Total Petroleum System. The Assessment Unit is shown herein as a geographic boundary interpreted, defined, and mapped by the geologist responsible for the province and incorporates a set of known or postulated oil and (or) gas accumulations sharing similar geologic, geographic, and temporal properties [...]