Chemically modified hydrogels to improve geothermal reservoir performance by enabling flow control via size-shifting microspheres
Year: 2026
Type: preprint
Abstract: Thermal short circuits, where fluids preferentially connect injection and production wells, are a leading cause of premature enthalpy decline in geothermal reservoirs. These pathways accelerate cooling, reduce effective heat transfer area, and limit reservoir lifetime. We propose a temperature-responsive hydrogel microsphere suspension as an “active tracer” that dynamically redirects flow away from cooled short-circuit channels while also tracing fluid flow via fluorescence spectroscopy. Highly idealized reservoir simulations with field-informed permeability distributions indicate that a yieldstress fluid with temperature-responsive behaviors may improve reservoir thermal lifetime by a factor of at least 24 to 59x while maintaining acceptable hydraulic performance. To develop a candidate “active” tracer intended to satisfy the assumptions of the idealized simulations, we synthesized poly(N-isopropylacrylamide) (pNIPA) microgels, characterized their swelling and rheological behavior, and conducted a large-scale laboratory experiment in an analog parallel-plate that demonstrates short-circuited flow behavior. These lab-scale results demonstrate that injected microgels clog cooled short circuits via swelling and diverted flow into hotter regions. This proof-of-concept establishes an attractive pathway for employing engineered materials to actively manage flow and extend geothermal reservoir lifetimes.
Source: ChemRxiv
Institutions: Cornell University, Clemson University
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221194450