GeothermieGradient

GeothermieGradient is a term used in geothermal science to denote the vertical temperature gradient in subsurface environments, describing how rapidly temperature increases with depth. It is typically expressed in degrees Celsius per kilometer (°C/km) and serves as a key parameter for assessing heat resources as well as for planning exploration and engineering of geothermal systems. The gradient reflects conductive heat flow modulated by local geology and can be influenced by groundwater movement, magmatic activity, and rock properties.

The gradient is usually estimated from borehole temperature measurements and is combined with the rock’s thermal conductivity to infer the temperature at depth and the potential energy content of a reservoir. In continental crust, typical values are on the order of 25–30 °C/km, but gradients can be higher near volcanic or magmatic intrusions and lower in regions with strong groundwater convection or thick sedimentary coverage.

Measurement and estimation often rely on temperature logs from wells, corrected for groundwater flow and seasonal effects. GeothermieGradient is used in conjunction with heat flow calculations (q = -k dT/dz) to estimate subsurface temperatures, reservoir quality, and feasibility for direct-use heat or electric power generation. It informs decisions on well depth, spacing, and the expected production temperatures.

Limitations include substantial regional variability and the influence of advection, heterogeneity, and structural features. As a local property, the gradient should be integrated with broader geological and geophysical data for reliable resource assessment.