Deeply buried reservoir porosity inversion method and device

The invention provides a deeply buried reservoir porosity inversion method and device. The method comprises the steps of carrying out the linear approximation on a rock physical model of a to-be-measured deeply buried reservoir based on Taylor series expansion; according to the rock physical model of the to-be-measured deeply-buried reservoir after linear approximation, determining the linear relationship between the longitudinal wave velocity and the transverse wave velocity and the porosity and the shale content; constructing a porosity inversion objective function according to the linear relationship between the longitudinal wave velocity and the transverse wave velocity and the porosity and the shale content; and solving the porosity inversion objective function, and determining the porosity of the to-be-measured deeply buried reservoir. According to the invention, the linear relationship between the longitudinal wave velocity and the transverse wave velocity and the porosity and the shale content is dete