Porosity inversion method under lithological constraint in geophysical exploration

The invention provides a porosity inversion method under lithological constraint in geophysical exploration and belongs to the field of oil geophysical exploration. A target function of porosity inversion is constructed according to seismic data and log data, and the log data includes porosity, gamma ray curves and wave impedance curves. The method includes: (1) wave impedance inversion; (2) lithological inversion; (3) acquisition of reservoir porosity by inversion of the target function under the constraint of inversed lithological data. By means of a logging-constrained seismic inversion method, resolution ratio is increased, thin reservoir recognition capability is greatly improved, and the porosity inversion method under lithological constraint is further adopted for inversion of internal porosity of sandstone to obtain high-precision three-dimensional porosity data.