| Title | Analysis of a Long-Term Test by Inverse Modeling Surface Deformation as Measured by InSAR |
|---|---|
| Authors | John AKERLEY, Kurt L. FEIGL, Michael A. CARDIFF, Patrick WALSH, Sam BATZLI |
| Year | 2018 |
| Conference | Stanford Geothermal Workshop |
| Keywords | InSAR data, subsurface characterization |
| Abstract | Following the completion of a production well and an injection well at an undeveloped geothermal field in Nevada, a long-term flow test was conducted to measure and understand reservoir characteristics. Measurements were made several times daily of variables including: volumetric flow rate of injection, volumetric flow rate of production, downhole pressure in production wells and wellhead pressure in the injection well. To better understand reservoir flow paths, a chemical tracer was also injected in the injection well. To measure the deformation, we use Interferometric Synthetic Aperture Radar (InSAR). Interferometric pairs of SAR images acquired every 11 days during the test show uplift around the injection well. To interpret the deformation field, we perform inverse modeling using the General Inversion of Phase Technique (GIPhT). This study demonstrates the value of combining InSAR data with conventional data to constrain models of reservoir characteristics and rock properties. For example, the modeled volume change estimated from the InSAR data is comparable to the value measured at the wellhead. Similarly, by matching the modeled pressure value to the measured value, we expect to be able to constrain the bulk modulus at the field scale. |