| Title | Reservoir Testing and Modeling of the Patua Geothermal Field, Nevada, USA |
|---|---|
| Authors | Sabodh K. GARG, Colin GORANSON, Stuart JOHNSON, John CASTEEL |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | Patua, Nevada, reservoir simulation, pressure interference testing |
| Abstract | To define the geothermal reservoir underlying the Gradient Resources Inc. (GRI) leases at the Patua Federal Geothermal Unit, GRI carried out an extensive exploration program consisting of geological, geochemical, and geophysical surveys, core hole drilling, well drilling, and pressure transient testing. Based on the data obtained from the well drilling and testing, a conceptual model of the Patua Geothermal Reservoir has been developed. The subsurface stratigraphy consists of a sequence of volcanic rocks overlying naturally-fractured granitic basement rockst. The geothermal reservoir is hosted by naturally-fractured granitic rocks with high-permeability fractures striking along northeastern and orthogonal northwestern trends. Pressure interference data recorded by monitoring coreholes and wells during discharge testing supports the concept of the lack of interconnection between coreholes completed in the volcanic rocks and production wells completed in the underlying granitic geothermal reservoir. Based on pressure interference data, the geothermal reservoir extends over at least ten (10) square miles. The conceptual model formed the basis of a detailed 3-D numerical model of the geothermal field. The numerical model was developed using STAR, a general-purpose geothermal reservoir engineering simulator. Temperature and pressure profiles recorded in shut-in wells, and pressure interference data obtained during reservoir/well testing operations were used to condition the numerical model. The latter model is used to assess the capability of the reservoir to supply geothermal fluid for the Phase I 30 MWe (net) geothermal power plant. |