Quillinan received a B.S. and M.S. in Geology from the University of Wyoming focusing in isotope geochemistry. Currently, he is a licensed professional geologist and research scientist at the University of Wyoming, Carbon Management Institute. Before coming to the University, Quillinan spent seven years as a project geologist with the Wyoming State Geological Survey. His recent research focuses on the intersection of energy resource production and groundwater resources. Quillinan has worked on groundwater challenges associated with the production of coal, coalbed methane, oil and gas (hydraulic fracturing), and CO2 sequestration; including estimating and identifying water/rock geochemical reactions, groundwater tracing, confined and unconfined aquifers, efficient reservoir dewatering techniques, and potential beneficial use for produced waters.