Interpretation of In-Situ Injection Measurements at the FORGE Site

Abstract

During April and early May 2019, injection testing was carried out in three zones in a vertical well in granitic rock at the FORGE site near Milford Utah. One zone was in the uncased barefoot section in the well. Two other zones tested were cased and perforated, further uphole. One of these zones was intentionally selected because of the abundance of favorably oriented (near-critically stressed) whereas the zone above it was relatively devoid of fractures. The results of injection-falloff and injection-flowback in each of these three zones are reported, and the implications of the measurements are described. Of particular interest are the preliminary interpretations of flowback data. Flowback offers an advantage over shut-in because of the reduced time to closure. These pressure transient data are reported in conjunction with the local discrete fracture networks, in conjunction with measured microseismicity and together with specific numerical simulations and history matching.