Geothermal Drilling Success at Blue Mountain, Nevada

Abstract

Exploration in a blind prospect has led to the confirmation of a geothermal resource at Blue Mt. Nevada. The latest results include drilling of three production wells into Piedmont faults. These wells produce from a 185 to 190ºC dilute benign brine reservoir. Short flow tests have shown prolific flow rates and indications of reservoir continuity.

Well entries have shown that system permeability is fault-dominated. This is confirmed by the results of seismic reflection imaging. Young faulting in the area includes intersecting range front faults that strike NW, NS, and NE. Exposure of basement rock outboard from the segmented range front reveals a long history of hydrothermal activity in this complex fault intersection zone.

The current conceptual model suggests that geothermal fluids equilibrate at up to 250ºC at depth in NE-trending Piedmont faults off the range front. Upflow feeds an artesian reservoir at 190ºC in the fault zone and then rises into a widespread shallow warm aquifer. Warm outflow mixes with meteoric water during flow into the basin. This shallow aquifer provided the initial evidence of the commercial temperature system.