Basement and magmatic resources

basement rocks

Basement (and crystalline) rocks are typically characterized by neglegible primary porosity and permeability,

Primary permeability is typically less than 1 mD, and often less than 0.1 mD, which means that they are not suitable for geothermal energy production based on natural flow.

However faults and fracture (networks and zones) can provide permeable path-ways for geothermal fluids, and can be exploited for geothermal energy production.

It appears that the fracture density and aperture size are the most important parameters for geothermal energy production in basement rocks. The fracture density is typically defined as the number of fractures per unit volume, and the aperture size is the width of the fractures. The fracture density and aperture size can vary significantly depending on the geological history and tectonic setting of the area.

magmatic rocks

Magmatic rocks can also be considered as basement rocks, albeit with a different origin and mineralogy. In the context of geothermal energy production, magmatic rocks are often characterized by high temperatures and can have significant (tectonically active) fracture and fault networks.