Determining Flow Conditions in Crystalline Bedrock Wells Using Dissolved Oxygen as a Tracer

Chlebica, Dariusz

Determining Flow Conditions in Crystalline Bedrock Wells Using Dissolved Oxygen as a Tracer

Tuesday, September 24, 2013: 9:30 a.m.

Gary Robbins , Natural Resources and the Environment, University of Connecticut, Storrs, CT

Dariusz Chlebica , Center for Integrative Geosciences, U. Connecticut, Storrs, CT

A novel approach to locate transmissive fractures and ascertain borehole flow conditions in fractured bedrock wells is presented that uses dissolved oxygen (DO) as a tracer. The low background DO level in a wellbore is elevated by circulating water through showerheads or injection of compressed air. Subsequently, the DO levels are monitored with time to ascertain ambient flow conditions or a slug test is performed to simulate pumping conditions. Downhole DO profiling is used to locate inflowing fractures, stagnant zones and ascertain wellbore flow rates. The method was tested in two 94.5 m deep wells in fractured crystalline bedrock (Hebron Gneiss) on the campus of the University of Connecticut, Storrs, CT. The transmissive fractures identified corresponded to fractures observed in televiewer logs and were comparable to flow meter results. The relative benign nature of dissolved oxygen along with the low-cost and limit logistics of deployment make this method advantageous in drinking water wells or where such wells are nearby.

Gary Robbins, Natural Resources and the Environment, University of Connecticut, Storrs, CT

Gary Robbins is a Professor of Hydrogeology at the University of Connecticut within the Department of Natural Resources and the Environment. His research interests are in the fate and transport of groundwater contamination and groundwater sustainability of fractured rock aquifers.

Dariusz Chlebica, Center for Integrative Geosciences, U. Connecticut, Storrs, CT

Dariusz Chlebica completed his M.S. in Geosciences at the University of Connecticut in the Spring 2013. He specializes in hydrogeology and has a wide range of experience in field testing and computer modeling, especially as it relates to understanding fracture flow conditions in crystalline bedrock.