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Cyclic injection, storage, and withdrawal of heated water in a sandstone aquifer at St. Paul, Minnesota: Field observations, preliminary model analysis, and aquifer thermal efficiency

January 1, 1994

In May 1980, the University of Minnesota began a project to evaluate the feasibility of storing heated (150 °C (degree Celsius)) water in the deep (180 to 240 m (meters)) Franconia-Ironton-Galesville aquifer and later recovering it for space heating. The Aquifer Thermal-Energy Storage (ATES) system was doublet-well design in which the injection/withdrawal wells were spaced approximately 250 m apart. High-temperature water from the University's steam-generation facilities supplied heat for injection. Water was pumped from one of the wells through a heat exchanger, where heat was added or removed. Water then was injected back into the aquifer through the other well. The experimental plan for testing the ATES system consisted of a series of short-term hot-water injection, storage, and withdrawal cycles. Each cycle was 24-days long, and each injection, storage, and withdrawal step of the cycle was 8 days.

The Franconia-Ironton-Galesville aquifer is a consolidated sandstone, approximately 60 m thick, the top of which is approximately 180 m below the land surface. It is confined above by the St. Lawrence Formation--a dolomitic sandstone 8-m thick--and below by the Eau Claire Formation--a shale 30-m thick. Initial hydraulic testing with inflatable packers indicated that the aquifer has four hydraulic zones with distinctly different values of relative horizontal hydraulic conductivity. The thickness of each zone was determined by correlating data from geophysical logs, core samples, and the inflatablepacker tests.

Citation Information

Publication Year 1989
Title Cyclic injection, storage, and withdrawal of heated water in a sandstone aquifer at St. Paul, Minnesota: Field observations, preliminary model analysis, and aquifer thermal efficiency
DOI 10.3133/ofr89261
Authors Robert T. Miller
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 89-261
Index ID ofr89261
Record Source USGS Publications Warehouse
USGS Organization Minnesota Water Science Center