Experimental design for hydrofracturing and fluid flow at the DOE EGS collab testbed

We describe our overall objectives and approach to designing the first experimental testbed of the EGS Collab project. This first phase of the project entails site characterization, drilling, stimulating, and performing flow tests using largely horizontal wellbores in phyllite of the Precambrian Poorman Formation, at the Sanford Underground Research Facility (SURF), located at the former Homestake Gold Mine, in Lead, South Dakota. This suite of hydrofracture and flow test experiments builds upon the stress and hydrofracture experiments performed at the nearby kISMET (permeability (k) and Induced Seismicity Management for Energy Technologies) site. While this paper provides an overview of the experiment design process, separate papers will describe the characterization of the site, the monitoring system, and other aspects of the project.