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Global Inversion of Pressure Dependent Acoustic Velocity Data Based on a New Double Relaxation Model
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 25th European Meeting of Environmental and Engineering Geophysics, Sep 2019, Volume 2019, p.1 - 5
Abstract
In this paper with the further development of our previously published single relaxation model (SRM), a new petrophysical model (the double relaxation model - DRM) describing the hysteretic pressure dependence of acoustic P wave velocity is presented. Since it is likely that several relaxation mechanism occur in the rock at the same time, the new model considers two or more physical mechanisms (e.g. the closure of pore volume or microcracks or friction on grain boundaries etc.) responsible for the pressure dependence of propagation velocity. Using the model equation as forward modeling formula, a global optimization algorithm (Simulated Annealing) was applied to solve the inversion problem and to determine the petrophysical parameters of the model. Inversion results proved that the calculated data matched accurately with measured data, so the new model was tested with success on laboratory measured data. On the other hand one can see that the new DRM model resulted in a more accurate fit compared to the SRM model.