Transport of a Temperature-Responsive Microgel in a Hele-Shaw Cell: Jamming at Low Temperatures for Geothermal Applications*

Commercially-successful geothermal systems require balance between thermal and hydraulic performance. An injector-producer well pair with exceptional hydraulic performance, for instance, may have inadequate thermal performance if the effective heat transfer surface area is insufficient. In such a circumstance the current state-of-the-art is to abandon such well pairs once production well temperatures fall below design/operating criteria. Here, a temperature-responsive microgel is introduced as a novel solution that enables cooled “short circuits” to be sealed off and circulating fluids to be redirected to hotter flow paths. By employing a counter-intuitive volume-phase transition, this treatment increases the effective heat transfer area and subsequently improves heat transfer efficiency by increasing production well temperatures. Bench-scale laboratory experiments are presented and the anticipated improvement to thermal performance is determined from a hypothetical case.