Thermal short-circuit mitigation in enhanced geothermal systems: a novel dynamic flow regulation technology using temperature-sensitive viscosity modifiers

Thermal short-circuiting in enhanced geothermal systems, caused by dominant flow paths, significantly compromises heat extraction efficiency and system longevity. This study introduces a dynamic flow regulation technology that employs carefully selected temperature-sensitive viscosity modifiers to autonomously optimize fluid distribution within fractures based on local temperature. Numerical simulations show that the proposed technology, which uses glycerol as a viscosity modifier, delays thermal breakthrough from 2.8 to 6.0 years and increases production temperature by 32.6 °C after 100 years. Flow velocity in dominant fractures is reduced by up to 44.07 %, while it increases by 41.22 % in high-temperature natural fractures, resulting in more uniform fluid distribution. This flow redistribution leads to enhanced thermal sweep, increasing the effective heat exchange volume by 26.04 %. The net electricity generation can be increased by 7.7 × 10⁵ MWh, representing a 56.06 % improvement over the baseline case. This study presents a novel, reversible, and field-practical strategy for flow regulation in enhanced geothermal systems, offering a robust solution to mitigate thermal short-circuiting and improve long-term system performance.