The simulated annealing method is introduced into genetic algorithm to form a hybrid algorithm, which can overcome the defects of genetic algorithm in optimization and avoid the premature phenomenon. According to the approximate formula of reflection coefficient of P-SV wave, the objective function of anisotropy parameter inversion is established. The anisotropy parameter inversion of TTI medium is achieved by using single algorithm and mixed algorithm respectively. The results show that the mixed algorithm inversion accuracy is higher and the process is more stable. Furthermore, Gaussian white noise with a signal-to-noise ratio of 5 is added to the data of the theoretical model to test the anti-noise property. The error of the inversion results is small and the anti-noise ability is good. Finally, the anisotropic parameter inversion of the modified Hess model is carried out, and the inversion profile is obtained, which is in good agreement with the original profile, and the effectiveness of the hybrid algorithm is verified. In addition, the research area is selected to perform inversion test on the actual data. The inversion results are good and the accuracy is high, which verifies the effectiveness of the hybrid algorithm in practical application.

Accurate understanding of the microscopic occurrence state of water flooding residual oil in porous media is of great significance for improving the development effect of water flooding and enhancing the recovery factor of water flooding in high water cut oil fields. Based on the verification of the Volume of Fluid (VOF) method, influence of physical property conditions and displacement modes on the microscopic occurrence characteristics and recovery factor of remaining oil in ultra-high water cut sandstone reservoir was studied by making full use of its advantages of tracking the dynamic change of two-phase interface and reproducing the physical process of microscopic seepage. By analyzing the microscopic seepage characteristics of typical pore structures and the stress of remaining oil, mechanism and law of different types of microscopic remaining oil are revealed: The increase of displacement velocity and the change of displacement direction make the distribution of microscopic remaining oil dispersed and the recovery efficiency is improved in different degrees under the condition of water and humidity; As the oil is wet and the viscosity ratio is high, the capillary resistance and viscosity are great, the remaining oil is mostly clustered and porous, and the recovery degree is relatively low.