Quantifying How Errors in Thermal Conductivity Estimates Affect Geothermal Production Models

摘要

Thermal conductivity can vary significantly within a rock type, sometimes by as much as +/- 50% of published values. The large range for thermal conductivities can be caused by variations in composition, laminations, impurities, fractures, compaction, grain orientations, temperature, fluid content, and other factors. If published values for thermal conductivity are used in geothermal production models, rather than actual measurements, it is easy to overestimate or under estimate production temperatures over the life of a geothermal well. In a low temperature 3D model of paired geothermal injection and production wells, altering the thermal properties of only one rock layer resulted in production well temperature changes of over 5°C, ranging from +3% to -5% from the baseline production temperature.