A study on inversion of reservoir parameters under coupling interaction of multiple physical mechanisms

The viscoelasticity, Biot-flow mechanism and the Squirt-flow mechanism are the most important mechanisms affecting wave propagation in the porous medium. Based on the viscoelastic BISQ model and elastic BISQ model respectively, we use Self-adaptive Hybrid Genetic Algorithm to perform the inversions of reservoir parameters under the coupling interaction of these three mechanisms. First, in order to test the effectiveness of the algorithm, we invert the theoretical data with different noises by use of self-adaptive Hybrid Generic Algorithm and Traditional real code generic algorithm respectively. Theoretical results show that Self-adaptive Hybrid Genetic Algorithm has the properties of strong immunity of noise and fast convergence of objective function, thus it is an effective inversion method for the reservoir parameters. Finally, based on viscoelastic BISQ model and elastic BISQ model, we apply the Self-adaptive Hybrid Genetic algorithm to perform the joint-inversion of the observed multi-scale frequency data of P- and S- wave. Comparing the inversion results on basis of these two models, we discover that the viscoelastic BISQ model explains well the dispersion of the observed data, it fits very well not only the P-wave but also the S-wave. This confirms the validity in low frequencies of the viscoelastic BISQ model.