EGS Collab/SIGMA-V Testbed-1 well locations and orientations.

Abstract

The EGS Collab is conducting experiments in hydraulic fracturing at a depth of 1.5 km in the Sanford Underground Research Facility (SURF) on the 4850 Level. A total of eight ~60m-long subhorizontal boreholes were drilled at that depth on the western rib of the West Access Drift. Six of these holes are used for geophysical monitoring, one is used for hydraulic fracturing and the remaining hole was designed as a production borehole. In addition to these eight boreholes, 4 5-m Jack leg boreholes were drilled for housing geophones. This submission package includes well head locations, total lengths of boreholes, their orientations (gyro data). The reported boreholes orientation data were primarily obtained with REFLEX GYRO (TM) survey right after the completion of each hole. Gyro based orientations were later verified and refined with the results of magnetic orientation survey. Well head locations were ascertained by Laser/Lider survey of the drift around the Testbed.