Testing of Two Exploration Wells at NAS Fallon, Nevada

Abstract

Two wells at the United States Naval Air Station in Fallon, Nevada (NAS Fallon) were tested to evaluate the resource potential in the vicinity of the two sites. GeothermEx, in coordination with the US Navy Geothermal Program Office (GPO), developed individual well test programs suited for the wellbore completions and expected characteristics of each of the two wells. A flow test was conducted on well 88-24 over the period March 20 to March 26, 2013 and an injection test was performed on well FDU-2D from March 22 to March 23, 2013. The flow test on well 88-24 indicated that the fluid originates from a shallow zone in the well at a temperature of only 170°F. The well has a Productivity Index of 9.5 gpm/psi, and wellbore simulations for a conventionally-sized, pumped well indicate that the well could produce 3,000 gpm with a pump set at 1,000 ft depth. The 170°F fluid is not hot enough for conventional electrical production, but may have some benefit for direct use. A maximum temperature of 284°F was measured near the bottom of the well, but there does not appear to be permeability in the bottom portion of the well. Geothermometer results from water samples collected during the flow test confirm the presence of higher temperature source fluids (295-300°F) and are consistent with the measured bottomhole temperatures. The injection test on FDU-2D indicated that this well has low permeability. The permeable zone could potentially produce 235°F fluid; however with a measured Injectivity Index of 0.02 gpm/psi the productive potential of the formation in the vicinity of FDU-2D appears very limited.