Details of the abstract
| Title of paper |
Time-lapse resistivity imaging : CSEM-data 3D double-difference inversion and application to the Reykjanes geothermal field |
| List of authors | Frédéric Dubois, François Bretaudeau |
| Affiliation(s) | BRGM, 3 avenue Claude Guillemin, 45060 Orléans, France |
| Summary | Time-lapse resistivity tomography bring valuable information on the physical changes occurring inside a geological reservoir. In this study, resistivity monitoring from CSEM data is investigated through synthetic and real data. We present three different schemes currently used to perform time-lapse inversions and compare these three methods: parallel, sequential and double difference. We demonstrate on synthetic tests that double difference scheme is the best way to perform time-lapse inversion when the survey parameters are fixed between the different time-lapse acquisitions. We show that double difference inversion allows to remove the imprint of correlated noise distortions, static shifts, and most of the non-linearity of the inversion process including numerical noise and acquisition footprint. It also appears that this approach is robust against the baseline resistivity model quality, and even a rough starting resistivity model built from borehole logs or basic geological knowledge can be sufficient to map the time-lapse changes at their right positions. We perform these comparisons with real land time-lapse CSEM data acquired one year apart over the Reykjanes geothermal field. |
| Session Keyword | 2.0 Theory, Modelling and Inversion |
| File upload |
2.0_time-lapse_resistivity_im_dubois.pdf
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