Deep geothermal reservoir potential depends on the local temperature gradient and host rock permeability. In areas with low primary porosity, such as the Duke River area, large-scale permeability is primarily associated with fracture networks. Fractures in the Duke River area are described based on 36 scanlines collected across 9 rock types from 0.8 to 22 km from the Denali fault. The majority of fractures are steeply dipping but have no preferential strike. The linear fracture intensity is high, and most fractures range from open to moderately wide. These attributes vary slightly by lithology but can be grouped into distinct hydrostratigraphic units. The distance from the Denali fault has a non-linear influence on fracture intensity and aperture and a negligible effect on fracture spacing and length. The fracture analysis presented will be used to develop a discrete fracture network to evaluate permeability in the Duke River area.
