Towards non-linear inversion for characterization of time-lapse phenomena through numerical modelling |
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Authors: | A Abubakar PM van den Berg JT Fokkema |
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Institution: | Schlumberger-Doll Research, 36 Old Quarry Road, Ridgefield, CT 06877, USA;, Laboratory of Electromagnetic Research, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands;, and Section of Applied Geophysics, Delft University of Technology, Mijnbouwstraat 120, 2628 RX Delft, The Netherlands |
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Abstract: | We compare two geophysical survey measurements of the same type made at different times in order to characterize the change in the geological medium during the elapsed time. The aim of this study is to develop a strategy using a full non-linear inversion algorithm as the interpretation tool. In this way, not only the location and the form of the changes are recovered, but also the changes in the material parameters of the geological medium can be estimated. In order to solve this fully non-linear problem, the so-called ‘multiplicative regularized contrast source inversion’ (MR-CSI) method is employed. The unique property of this iterative method is that it does not solve the forward problem at each iterative step. This makes it possible to use the non-linear inversion algorithm for large-scale computation problems. The numerical results show that by taking into account the non-linear nature of the problem, interpretation of the time-lapse data can be significantly improved, compared with that obtained using linear inversion. |
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