Deep TVZ Resource Delineation
Combined MT, seismic, gravity and magnetics to identify heat sources, areas of possible deep-seated permeability and fluid flow, and potential targets for future deep drilling, and to understand time-spatial changes to geothermal fields.
Project Leader: Grant Caldwell
Task 1: Seismology (Task Leader: Stephen Bannister)
- Earthquake seismic waveforms from geothermal reservoirs analysed to give high-resolution micro-earthquake locations, and to characterise the nature of the seismic sources
- Shear-wave velocity image volume extended in the vicinity of potential deep drilling targets or other regions of interest
- New seismic measurements acquired
Task 2: Magnetotellurics (Task Leader: Ted Bertrand)
- Aquisition of MT data and determination of the resistivity structure at Ohaaki
- 3D inverse modelling for deep geothermal study area
- Development of a joint MT-seismic rock property model at 3-7 km depth
- Heterogeneities in 3D MT and seismic data interpreted with respect to deep drilling targets, and interpolation and qualitative comparison schemes developed
- MT experiments to assess deep resistivity changes resulting from re-injection or production
- Algorithms for improved 3D inversion of MT data
- New MT measurements to expand coverage in the southern-central TVZ
- Advanced geophysical techniques and combinations of geophysical techniques for identification of deep geothermal resources
Task 3: Aeromagnetics & Gravity (Task Leader: Supri Soengkono)
- Reinterpretation of TVZ basement structure using regional gravity and down-hole density data
- Additional geophysical data obtained to help interpret structures identified in the MT and seismological surveys
- Implications for deep geothermal resource prospectively in the southern-central TVZ