| Title | Magnetotelluric Characterization of the Habanero Geothermal EGS Project: Initial Results on Fluid Injection Monitoring |
|---|---|
| Authors | DIDANA Y.L, Stephan THIEL and Graham HEINSON |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | magnetotellurics, geothermal,EGS, fluid injection, resistivity |
| Abstract | Magnetotelluric (MT) data was collected across the Habanero enhanced geothermal system (EGS) project site in the Cooper Basin , South Australia in view of delineating the crustal conductivity structure of the geothermal area and to monitor fluid injection of Habanero 4 geothermal borehole. Two MT surveys have been carried out. The first MT survey consists of two perpendicular profiles, each about 20 km long. 2D inversion of MT data of the two profiles shows three main resistivity structures to a depth of 10 km: 2 km thick good conducting ( less than 10Ωm) surface layer is underlain by relatively high resistivity( less than 100Ωm) followed by high resistivity( more than 100Ωm). The low resistivity surface layer shows areas with poorly consolidated sands, siltstones and clay stones. Below the conductive layer, is a relatively high resistivity zone that can be correlated to consolidated sandstones, siltstones and shale. The high resistivity structure is associated with basement granitic formation. The second MT survey was conducted during fluid injection of Habanero 4 well in November 2012 which lasted for two weeks. Initial results from MT residual phase tensor analysis of the fluid injection at depth of about 4 km show fractures opening in NNE direction. This result is in good agreement with seismic cloud observed in the Habanero area during fluid injection. |